Astronomy 100g Midterm 2 & 3/ Final Flashcards (Lectures 12- 40)

Michelson Doppler Imager

3rd instrument on SOHO mission, obtains solar images that are nearly identical in size to those we have been obtaining at 60 foot tower, Rhodes served as an MDI co investigator,

nitrogen (N2)

3rd most important gas to be outgassed, largest single component in out current atm,

Henry Norris Russell

American astronomer, studied absolute magnitudes and spectral classes of the stars whose distances were known then in 1913, theories of star birth began with (blank) early in the 20th cent

George Gamow

American physicist who was 1st to suggest that the universe began as fundamental particles which were then fused together into heavier elements during the Big Bang

Kamiokande and Superkamiokande

Japanese neutrino detectors made by Koshiba

Jupiter's motions

Jupiter is fastest rotating planet (under 10 hrs), cloud bands near equator rotate slightly faster than bands near poles (true for all gas giants bc they don't have crusts)

photochemical reactions

Jupiter is very colorful, photo-photos= Greek for light, chemical= reactions, enough sunlight produces diff colors in atm

Apollo asteroids

approx 50 asteroids with diameters larger than 1 km w/ eccentric orbits that cross Earth's orbit, (could crash into them but prob not)

BL Lac objects (blazers)

are especially luminous active galactic nuclei that vary in luminosity by a factor of up to 100 in just a few months,

Kuiper belt

band of comets and dwarf planets that exist closer to the solar system than the oort cloud, Trans Neptunian Objects ( almost all are near orbit of Neptune)

CNO Cycle

carbon or (blank) is a series of nuclear reactions that results in the fusion of hydrogen into helium, using carbon-12 in the process, carbon acts as a catalyst in the (blank),

volatile

easily vaporized, moon has less (blank) substances than Earth,

solar limb

edge of solar disk

length compression

einstein also said that the two observers would disagree on the lengths each would measure, but only along the line of sight connecting them, he said that each would perceive the other's lengths as being shorter than the other would measure

normal galaxies

elliptical, spiral, barred-spiral, and irregular are types of (blank) by Hubble's classifications, most galaxies have (blank) shape

interstellar neutral hydrogen

emits radiation at wavelength of 21 cm, (blank) was measured by Purcell and Ewen in 1951 with a specially built radio telescope

Hubble Time

Tsub0= (blank)= maximum possible age of the universe

George Ellery Hale

born in chicago, US Astronomer, in 1908 he was the 1st person to detect magnetic fields on Sun, used Zeeman Effect at 60 foot solar tower of the Mt. Wilson observatory, first scientist to measure a magnetic field that isn't Earth's,

debris

an accumulation of rock fragments that aren't the Sun (large object) and planets and larger moons (medium sized objects), can be asteroids, meteoroids, comets, and dust

Mariner 9

orbited Mars took many photos

Moon

orbits Earth, was formed about 4.6 billion years ago, Most craters formed between 4.2 and 3.9 billion years ago, was dated using radioactive dating techniques from rocks from Apollo mission, after the cratering ended, the Moon's interior became hot for a second time due to radioactive decay and molten lava flowed. These flows ended about 3.1 billion years ago, (blank) has remained unchanged since then, avg. density is 3.36 g/cm^3 (62% of Earth's density due to smaller lunar mass, has less volatile substances than Earth (could be caused by smaller mean density), Moon's relative size is .27 of Earth's diameter, Moon isn't oblate but spherical (centrifugal force and rotational speed made Earth oblate), primitive Moon was roughly made of same material as Earth's seafloors (basalt) , atm is called temporary bc same particles aren't there always bc of solar winds, a weak magnetic field indicates a small iron core, moonquakes occur when micrometeorites bombard moon or when it is at perigee

shepherd moons

pairs of orbiting moons, small, cause ring features, example of resonance, relationship w/ belts

coma

part of a coma's head made up of a diffuse cloud of gas and dust

protons

part of atom's nucleus, massive and positively charged particles in nucleus

total space velocity

pythagorean theorem, a star's actual motion relative to the sun and combines both its radial and tangential velocity components, can be calculated from radial velocity and tangential velocity components (V total)^2= (V radial)^2 + (V tangential)^2

equation of state

relates pressure, density, and temp in gaseous solar matter, Prof. Dappen is expert in equation of state,

Mid-Atlantic Ridge

rift zone running down spine of undersea mountain range located 1/2 way between Europe and US and 1/2 way between Africa and South America, observations associated with (blank) that lead geophysicists to believe Wegener was correct due to heat, age of rocks, and earthquakes that occurred there

Neptune's Rings

rings exhibit lumpiness

Micro-meteorites

smallest meteoroids are slowed down at the top of Earth's atm and are not evaporated during their passage, land on Earth's surface constantly

blue shift (violet shift)

source of sound/light that moves toward the observer results in (blank) with a higher frequency and shorter wavelength

density

the (blank) of Earth's atmosphere decreases with increasing height from within, the core is most dense because the materials around it (mantle/crust) compress it

inclination

the (blank) of a planet's orbit is the angle between the plane of a planet's orbit and the ecliptic plane, how close to the ecliptic is each planet's orbit, mercury and pluto have highest (blank),

temperature

the (blank) of the Earth's atmosphere generally decreases with increasing height except for in inversion layers (where temperature temporarily increases with increasing height)

radioactive dating techniques

use of minerals to date the origins of planets/moons, was used on 840 lbs of Moon rocks brought back to Earth by Apollo,

Cassini mission

went into orbit around Saturn in July 2004, sent the Huygens probe toward the atm of moon Titan in December 2004 and entered atm of Titan in 2005, Cassini still in orbit around saturn, and discovered radiation belt, discovered moons around Saturn,

occultation

what happens when solar system object passes between us and a star (temporarily interrupts light from star)

neutron star

what is left of core of a middleweight star (after explosion) that has collapsed to the point at which it is supported by neutron degeneracy, the diameter of a (blank) is only .2% of the diameter of a white dwarf and the (blank) is a billion times more dense, have masses of less than 3 solar masses, a typical (blank) has 1.5 solar masses, 20 km diameter, 10^15 g/cm^3 density, and temp of 10,000,000 K, possibly have solid surfaces and experience star quakes, discovery of pulsars gave us idea that (blank) exist, Baade and Zwicky of Caltech in 1930s discussed (blank), a (blank) has super conducting protons and superfluids neutrons at core, then superfluids neutrons layer, then crust,

solar maximum

when most sunspots are visible on solar surface, after this the number of sunspots decreases, last (blank) was in 2012,

blue moon

when two full moons occur within one calendar month, the second of the two full moons is called a (blank)

Homestake Mine

where Ray Davis developed original Solar Neutrino detector, in South Dakota,

pressure

force per unit area, is determined by molecular speed and density,

waxing (growing) crescent

amount of moon that appears to be illuminated in growing through out the month

granulation

division of the Sun's surface into small convection cells

tectonic plates

12 pieces of the lithosphere (shell) which knit together but have been cracked and fractured, the places where it is cracked are rift zones

Neptune's Moons

13 of them, Voyager 2 discovered many of them, moon Nereid shows most eccentric orbit of any moon in solar system,

average density

ratio of mass to volume, the (blank) of the Earth is 5.52 g/cm^3,

Saturn's Moons

62 moons, most of which consist of dirty ice, Major moons include Titan (has an atm), Mimas, Enceladus (has water geysers shooting water into space, Dione,

fireballs

very bright meteors, some are large enough that solid chunks survive and hit the Earth

Samuel Schwabe

1831, first noted Great Red Spot, pointed out sunspot cycle as well (wasn't astronomer), in 1851 he discovered the sunspot cycle cycle lasts about 11 years on average

meteorites

(blank) cause craters on the moon, interplanetary chunk of matter that has struck a planet or moon, craters remain intact on the moon bc there is no atmosphere to keep (blank) out, classified into 3 categories: Irons, Stones, Stony Irons, about 90% of all meteorites are stones,

flat universe spacetime model

(blank) is one in which two parallel straight lines will always remain parallel, it is based upon Eucidean plane geometry, such a universe will continue to expand in the future, but it will slow down the rate of expansion until it almost stops, the sum of three angles in a triangle is exactly 180 degrees in the (blank), one of Friedmann's models of spacetime

star clusters

(blank) are important for three reasons 1. all of the stars in a given cluster are at about the same distance from us, so their relative apparent magnitudes are direct measures of their relative absolute magnitudes 2. all of the stars within a cluster formed at about the same time 3. all of the star within a given cluster have the same chemical composition, two examples of (blank) are subaru and peiotes, globular and open (blanks)

neutron degeneracy

(blank) cannot support a neutron star whose mass is greater than about 3 solar masses, (blank) like electron degeneracy is a force outward which can be maintained if the star's mass stays within a certain boundary if the star's mass exceeds this boundary the star will implode

Eratosthenes

(276-195 BC) devised a way to measure Earth's size, he observed when the Sun was at the zenith at Syene it was about 7 degrees from overhead at Alexandria. 7 degrees is about 1/50 of a full circle so the circumference of the Earth should be 50x the distance from Syene to Alexandria or (50 x 5,000 stadia= 250,000 stadia), syene's altitude is 23.5 degrees on Tropic of Cancer (same as obliquity of ecliptic), Ptolemy used geocentric parallax to measure relative distance from Earth to Moon,

elliptical galaxy

(blank) is one of class of normal galaxies that have smooth spheroidal shapes, no patchy things or spiral arms, classified from round (E0) to (E7) very elongated, most of galaxies in existence are (blank), but most of these are smaller than spiral galaxies, a few giant (blank) have 10^13 stars and are thus larger than any spiral galaxy, (blank) contain primarily old, in clusters where galaxies are packed close together, (blank) dominate, supporting the notion of frequent mergers, in loosely packed clusters of galaxies (blank) are fairly rare, Population II stars, appear to have relatively little gas or dust in them, it appears little star formation is still going on in most (blank), largest known galaxies are cD (supergiant) ellipticals, the cD- central, dominant, smallest (blank) are dwarf (blank),

radiant

(blank) of a meteor shower is the point in the sky from which the meteors of a shower appear to radiate (the vanishing point)

Comets

(blank) orbit the Sun according to laws of gravitation (proved by Newton), orbits are eccentric bc they're only visible for short amount of time, can have either prograde or retrograde orbits depending on where they passed Saturn/Jupiter, not limited to ecliptic but are randomly oriented, have pristine material at center, water-ice mantle, some also have tarry crust, (blank) die through gradual evaporation of their nuclei, through evaporation of their volatile materials leaving chunks of rock, by falling into the Sun (as Comet ISON did), (blank) are thought to be material that formed in outer solar system from the remnants of small eddies, NASA has sent 3 spacecrafts to 3 diff comets,

Crust of the Moon

(blank) ranges in depth from 60-100 km and is thinner on the side facing Earth, density of rocks on lunar surface is similar to density of Earth's surface, but Earth has more overlying material which makes it's density increase as we go inward,

Type II Supernovae

(blank) result from massive stars, reveal prominent hydrogen lines, the process by which (blank) occur is not well known but is thought to begin with the conversion of silicon to iron, the fusing of silicon to iron in a supergiant star will take only a few days which is remarkably short period of time, because the iron fusion reaction absorbs more energy than it releases, the core shrinks, heats up, but produces no new more massive elements, once its mass reaches the Chandrasekhar limit, the core collapses violently, after reaching its minimum size, the core rebounds, colliding violently with infalling material, the collision between the infalling material and the rebounding core produces two effects: 1) enough energy is produced to fuse iron into heavier elements 2) shock waves are sent outward that throw off the outer layers of the supergiant, these shock waves may be further heated by neutrinos escaping the collapsed core, elements heavier than iron cannot be formed without some source of energy, heavy elements found here on Earth are thus the product of supernovae explosions in the distant past that ultimately became part of the interstellar material from which the Earth was formed, the process by which the nuclei of heavy atoms are created inside the cores of (blank) is called nucleogenesis, (blank) contains prominent hydrogen lines; results from explosion of a single star, (blank) have hydrogen and helium layers have not been lost and still have portions of outer atms which haven't been lost unlike Type I, bc (blank) are thought to occur in such massive stars, they are also only found in regions where recent star formation has occurred, Fusing iron takes energy unlike every other nuclei fusing(hydrogen, helium, berillium is exothermic) while iron is endothermic and sucks energy out of core--> begins to implode and gets past point of electron degeneracy that neutrons become degenerate and implosion turns around resulting in reverse and it explodes after reaching Chandrasekhar limit-->(blank) (neutron star if its middleweight) or (black hole if superweight)

binary pulsar

(blank) was 1st discovered in 1974 by Joseph Taylor and Russell Hulse, because the system has a short period of revolution (< 8 hrs) it could be determind that the (blank)'s orbit precesses at the rate of 4 degrees per century, the (blank) has a mass of 1.441 solar masses and its companion mass is 1.3874 solar masses, (blank) is important bc it confirms predictions made by general relativity, was 1st instance of use of general relativity to calculate a stellar property, & 1st precise determination of mass of a neutron star, as 2 (blank) orbit each other gravitational waves are given off which take energy from the orbital motion of the stars and their orbital period shortens,

Recombination Era

(blue squiggle photons (shorter wavelength higher energy) freed electrons + positively charged nuclei= neutral atoms (and decreased wavelength and energy red long photons)) beginning with the end of the Opaque Era, some of the neutral atoms remained intact, from 379,000 to 1,300,000 years after the Big Bang additional electrons re-combined with nuclei to create even more neutral atoms, photons lost enough energy that we ended up not being able to ionize neutral atoms any longer,

Hipparchus

(greatest pre Christian astronomer) had the 1st star catalog w/ corresponding brightness (apparent magnitudes) which he made in 2nd century B.C., bc babylonians didn't note this, he introduced idea of magnitude,

G stars

(like the Sun) spend about 30 million years in protostar phase,

Middleweights

(moderately massive stars) are stars containing between 4 and 12 solar masses, stages of a (blank) star: 1) protostar 2) main sequence star with a mass of 4-12 solar masses and a core mass up to 3, 3) red giant, 4) supernova 5) supernova remnant nebula and a Pulsar, after reaching the Chandrasekhar limit a (blank) becomes a type II supernovae--> neutron star

Mar's motions

(planet) orbits Sun at an avg of 1.524 AU (228 million km), planet's orbit is more eccentric than Earth's-> (planet)'s distance from sun varies from 210-250 million km & Earth-Mars distance at opposition varies from 55million km to 10million km, (planet) takes 1.88 Earth years to complete orbit around sun, obliquity is almost identical to Earth's

Mar's sidereal rotational period

(planet)'s (blank) is 24hr 37 min, its day is 24 hr 40 min long (similar to Earth's)

Sequence of Particles

(quarks/leptons/photons of energy--> protons and neutrons create nuclei --> electrons create atoms w/nuclei)

interstellar gas

, can cause absorption lines in stellar spectra, absorption lines due to (blank) tend to be narrower than those produced by a star's atm bc its colder, (blank) will generally be much cooler than the gas of the stellar atmosphere, emission nebula is (blank) that flouresces due to UV light from a star near or within the nebula

Astronomical Unit (AU)

1 unit = avg distance from earth to sun, also = to 1 semi major axis of Earth's orbit around sun, Copernicus used (blank) as a roadmap scale but didn't know exactly how big the AU was, 93,000,000 miles

Experimental Tests of General Relativity

1) Deflection of starlight by the Sun, if the principle of equivalence is valid then a beam of light should bend in the presence of a massive object, this bending of light was confirmed during the 1919 Total Solar Eclipse Expedition led by Sir Arthur Eddington--his British team catapulted Einstein to worldwide fame, the stronger the gravity is the more a beam of light will bend toward a massive object 2) Perihelion advance of planet Mercury, this direction is observed to advance by a larger amount each orbit than was predicted by perturbation theory which used only Newtonian physics 3) the gravitational redshift of photons leaving a star, the (blank) says that the curvature of spacetime around a star will cause the photons which leave that star to lose energy but the special theory says that the light cannot slow down as it leaves the star so photons must by redshifted to lower frequencies or longer wavelengths, this was first measured by American Astronomer Daniel Popper in 1954 for a white dwarf star, it was only measured later for the Sun bc it doesn't curve spacetime as much as a white dwarf and hence redshift is smaller and harder to measure, 4) the time delays of Viking radio signals, since Einstein 1st proposed his theory of (blank) other competing theories have been proposed, the time delays of 2 Viking spacecraft which are in orbit around Mars have been carefully measured and appear to best match predictions of Einstein's theory, 5) binary pulsars-- was 1st instance of use of (blank) to calculate a stellar property & 1st precise determination of mass of a neutron star

20th century cosmological ideas

1) Special Theory of Relativity in 1905 2) General theory of relativity in 1915 3) Alexander Friedmann's expanding relativistic solutions of Einstein's equations 1922 4) Edwin Hubble's demonstration of the existence of other galaxies 1924 5) Hubble's demonstration that the entire universe is expanding 1929 6) the development of modern quantum mechanics 1920s/30s 7) development of the big bang theory 1940s/50s 8) development of the quark theory of matter 1963 9) the observational detection of cosmic microwave background radiation 1965 10) development of the Grand Unified Field Theories of High-Energy Physics 1970s/90s 11) Introduction of the Inflationary Scenario of the Big Bang Model (1981) 12) discovery of the Cosmic Background Explorer Satellite of Large-Scale Temperature Fluctuations in the Microwave Background

Formation of the Solar System

1) all planets revolve around sun in same direction and all their orbits are nearly circular except Mercury and Pluto 2) All planets lie in nearly same plane of revolution except Mercury and Pluto 3) Most planets rotate in the same direction except Venus, Uranus, and Pluto (retrograde) 4) majority of planetary satellites revolve around their parent planet in the same direction as planets around sun (RHR) 5)Titius and Bode's law used to explain pattern of planet spacing but it has no known physical cause 6) outer planets contain more volatile elements and are less dense than inner 7) all of the planets and moon that have a solid surface show evidence of craters 8) all jovian planets have at least one ring system 9) asteroids, comets, and meteoroids populate the system along with the planets and each category of objects has its own pattern of motion and location 10) planets have more total angular momentum than does the sun, even though sun has most of the mass 11) recent evidence shows planetary systems in various stages of development may exist around other stars

Properties of gases

1) as molecules interact, diff molecules have diff speeds 2) Avg speed of molecules depends on the temp of it 3) at a given temp the less massive molecules have greater speeds than do the heavier ones, the formula for kinetic energy= .5(mass)(velocity^2), the temperature of a substance is defined by the average kinetic energy of its molecules, there is minimal free hydrogen in Earth's atm because low-mass hydrogen molecules can achieve escape velocity at temps of the upper atm, if a planet retains atm depends on the (blank) --> thermal speed of primitive atm as well as escape velocity

galactic disk

1/5 galaxy components, flat dense portion of a spiral galaxy that rotates in a plane around the nucleus, contains stars and most of the gas and dust in the galaxy, it is about 1,000 parsecs thick, almost all O-type (young/massive) stars lie within about 100 parsecs of the galactic plane,

galactic corona

1/5 galaxy components, hot ionized gas in the outer part of the halo is called the (blank), primarily invisible bc it doesn't flouresce,

galactic halo

1/5 galaxy components, the part of a spiral galaxy on both sides of its disk; fairly spherical in shape, it is comprised of stars, star clusters, and gas, may sometimes contain large amounts of dark matter, flat disk of dust, halo is thought to extend well beyond visible portion of galaxy, stars in the halo are older than those in the disk,

galactic nucleus

1/5 galaxy components,is the very tiny central part of the nuclear bulge which is thought to contain a super-massive black hole, center of the galaxy lies in the direction of Sagittarius, it wasn't until the development of radio astronomy that we could "look" at the galactic nucleus, satellites have revealed that the galactic nucleus is a very bright infrared source, an even smaller source in the nucleus emits tremendous amounts of energy in the form of gamma rays, suggesting that at the center of the Galaxy is a gigantic or supermassive black hole, many galaxies have these, recent discoveries of fast-moving stars and gas near the center of the Galaxy support the black hole hypothesis, stars are concentrated here, is source of radio and other rays

nuclear bulge

1/5 galaxy components,the central region of a spiral galaxy, the the Milky Way it is less than 10,000 parsecs in diameter, our galaxy is round and flat, thin except for bulge (similar to Star Ship Enterprise), (blank) is thought to be very old, metal-rich long-lived K- and M-type stars predominate here, the center portion of the milky way was 1st to become dense enough for stars to form, dense pockets in orbit around center became globular clusters

Uranus' ring system and moons

10 thin rings that contain very little material, were discovered using ground based stellar occultation and was confirmed later by Voyager 2 along with more moons,only reflect 5% of sunlight that hits them so they can't be seen from Earth, while Saturn's rings reflect 80%, innermost moon Miranda appears to have been torn apart then reassembled, has two shepherd moons, all 27 moons are low density, icy worlds,

Antonia Maury

1880s astronomer who discovered smearing effect in absorption lines which is due to diff density of star's atm, developed luminosity classes to account for this, temp is most important thing to determine differences in star's atm but density is second,

Giovanni Schiaparelli

1887, artist who drew Mars's canali-channels, was misinterpreted by public to mean canals which were physically dug out by intelligent life,

The Expanding Universe

1929: Hubble announces that pattern of redshifts of distant galaxies indicates that they are moving away from us and that the more distant the galaxy, the faster it is moving away 1931: Hubble & colleague Milton Humason extended the Hubble Law to even larger velocities and distances, the entire universe of galaxies is expanding and no one galaxy is in any central position, that the universe is expanding is a conclusion based on the observations of redshifts of distant galaxies, it is these clusters of galaxies that are moving away from us, in certain cases individual galaxies within the Local Group are moving toward us, expansion of universe is an increasing separation of clusters, prior to 1998, most data showed galaxies moving slower now than in past and data hinted that slowdown is not enough to stop the expansion but data weren't accurate enough to confirm whether the universe is open or flat, then in 1998 data suggested that the expansion is accelerating/ speeding up rather than slowing down, the two teams that made the competing announcements that they had discovered that the expansion was accelerating rather than decelerating were the Supernova Cosmology Project and the High-Z Supernova Search Team, the leaders of these two teams shared the 2011 Nobel Prize in Physics since their results have become accepted by most other cosmologists, now that more recent studies appear to be correct their observations of an accelerating expansion lend support for the previously discarded Positive Cosmological Constant model, but we still need to discover the source of the extra energy which causes the acceleration,

Mariner 2

1962, flew past venus

Mariner 4

1965, flew past Mars and took 1st 22 photos,

Mariner 5

1967, flew past venus,

Mariners 6 & 7

1969, flew past Mars (took 100 photos--> ended speculation about canali)

Apollo 11

1969, landed 1st men on moon

Pioneer 10

1973, flew within 130,000 km of Jupiter

Pioneer 11

1974, flew within 50,000 km of Jupiter, Pioneer 10 was successful so they tried again, measured magnetic field and magnetosphere, passed saturn in 1979,

Venera 9 and 10

1975 USSR, landed on venus and gave first surface pictures,

Pioneer Venus

1978, orbited and landed on venus, made radar map of surface from orbiter, found sulfuric acid clouds from volcanic interruption,

Venera 13/14 & 15/16 &17/18

1982-1985, USSR returned color photos from surface of Venus, made best radar images of Venus prior to Magellan, landed on Venus,

Phobos

1988, USSR, orbited Mars near orbit of Phobos and went out of control before attempting to vaporize small portions of its surface for remote control analysis,

Galileo probe

1989, is orbiting Jupiter, previously found out Jupiter's composition by probing ATM,

Magellan

1989, orbited Venus and mapped surface with radar, showed evidence of landslides possibly from tectonic activity which we thought Venus's crust was too thick to have before

Ulysses

1990, flew out of the ecliptic plane to study polar poles

Freidrich Bessel

1st detected stellar parallax in 1838, used star 61 Cygni

W. Huggins

1st made stellar radial velocity measurement, in 1868, studied Sirius

Mars Global Surveyor

2006 is orbiting Mars for 1 Martian year, detected evidence of current flows of water down side of some Martian craters

sidereal day

23 hours 56 mins, amount of time that passes between successive passages of the vernal equinox across the meridian, (blank) is 4 mins less than sidereal day bc the simultaneous rotation and revolution of the Earth

solar day

24 hours, amount of time that elapses between successive passages of the sun across a location's celestial meridian, (blank) is 4 mins longer than sidereal day

Saturn

2nd Jovian planet from Sun, almost 10x greater diameter than Earth, sidereal orbital period= 29.46 Earth years, obliquity is slightly larger than Earth's, differential rotation, more oblate than jupiter (most oblate planet) bc lower surface gravity means atmosphere can be more extended around equator, clouds are less colorful than jupiter's bc there are less photochemical reactions at top of atm (poles receive less light) giving less colors bc of inverse square law of light (saturn is more far from sun), it is also less colorful because a layer of methane haze above clouds on tops of saturn further blur out color differences, experiences differential rotation, rotation rate is 10h 39mins, even more oblate than Jupiter, is a diminutive version of Jupiter in 5 ways, show aurorae

CO2 (carbon dioxide

2nd most important gas to outgas, combined with surface rocks to form carbonate materials, a lot of CO2 was trapped in oceans, Venus also had a lot of CO2 come out but this Co2 stayed in the atmosphere--> venus is hot and hellish (the same thing would have happened to Earth if CO2 stayed in our atm)

open/ hyperbolic universe spacetime model

3rd of Friedmann's models of spacetime, (blank) is based off of hyperbolic geometry, in (blank) the expansion of the universe will continue forever and will not slow down as much as in the flat model, two parallel lines will diverge in the open model--> the geometry of a saddle

argon

4th significant gas to outgas, a product of certain radioactive decays so its relative abundance has helped us date the Earth,

Pluto's Moons

5 total moons, Charon discovered by James W. Christy, Hubble Space Telescope was used to discover Hydra, Nix, Cerberus, and later Vulcan was discovered,

ozone layer

50 km above earth's surface, an efficient absorber of UV radiation from the Sun, absorption causes temp to peak at the height of (blank), has protected life on Earth for billions of years, during 20th century the release of chlorofluorocarbons has reduced the amount of ozone, idea of global warming 1st introduced by Roland and Molina,

Jupiter's Moons

67 moons, divided into several smaller groups (4 inner moons which orbit very close to Jupiter and are probably fragmented moonlets, 8 outer moons which orbit 2 groups of four that are traveling in opposite directions (means they were prob captured) which have eccentric orbits dark surfaces, 4 large satellites orbiting in nearly circular orbits which are named the Galilean moons, the smallest of 4 galilean moons is 5,000 times more massive than is the largest remaining Jovian moon (their names are Io, Europa, Ganymede, Callisto), Jupiter and its moons must resemble the formation of the solar system bc the moons close to Jupiter are denser and contain more volatile elements while moons farther out decrease in density and increase in volatile elements

Maunder Minimum

70 year interval of time from 1645 to 1715 where there were relatively few or no sunspots visible, temps dropped in the northern hemisphere--> lakes and rivers froze over, glaciers grew, (blank) is part of what is known as the Little Ice Age

evolution of the galaxy

70% of known globular clusters in the Milky Way have an average heavy-element content 1/20 that of the Sun, star clusters provide a convenient method of measuring the age of stars, since there are no white dwarfs near the Sun, this portion of the galactic disk must be no older than about 10 billion years, stars in the halo are older than those in the disk, the youngest stars in the globular clusters are about 11 billion years old and the oldest are between 12 and 13.7 billion years old, from relatively scant data it is thought that the nuclear bulge must also be very old, metal-rich, long lived K- an M type stars predominate there, the initial cloud has some rotation and as it contracted it spun faster, the rotating matter formed into a disk, density waves formed in the Galaxy's disk, creating the spiral arms where star formation continues today, this is just one of several models proposed for the creation and evolution of the galaxy,

Uranus

7th planet from sun, jovian, 4x greater diameter than Earth, barely visible to naked eye and was plotted on star charts as early as 1690, angular size is very small but was discovered by Sir William Herschel in 1781, sidereal period is 84.01 Earth years, obliquity is greater than 90 degrees ( like Venus) is actually 97.86 degrees, is 8 degrees below ecliptic plane, -->uranus rotates retrograde, rotates once in 17 hrs, 27 Moons, naked eye planet (but orbits sun slowly so it wasn't known to be a planet at first, in 1977 an improved determination of Uranus' diameter was made by observing the occultation (passing of one astro object in front of another and light from distant object is dimmed when closer passes in front) of a star by the planet, takes 64 Earths to fill Uranus once, low density of 1.2 indicates little to no rocky core, atm is similar to jupiter and saturn, mostly hydrogen and helium w/ some methane, no thick cloud layers so the methane is in its atm absorbs red light reflects blue green, isn't as deep blue as neptune, north pole of uranus is below ecliptic, rotation and moons are almost at 90 degrees to rest of planets, has aurora, has 10 thin rings containing very little material discovered with occultation on Earth but confirmed by Voyager 2, cloud bands rotate differentially, uniform surface temp of -200 degrees celsius

Neptune

8th planet from sun, blue planet, small eccentricity (very circular), diameter is almost 4x Earth's, very close tilt to ecliptic, similar to Uranus in diameter and composition (Neptune is bluer), while Uranus is featureless-- Neptune shows weather patterns and methane crystal clouds, further from sun than Uranus so methane in atm makes it absorb even more red (and reflect more blue), had a Great Dark Spot but has since disappeared, orbital period= 165 years, radiates more internal heat than it gets from sun, very windy, temps are uniform because of atm, experiences most extreme differential rotation, magnetic field rotates faster than atm, greater density indicates larger rocky core, similar obliquity to saturn,Uranus and Neptune are smaller 2 gas giants but Neptune radiates more internal heat than Uranus (bc of contraction or bc of heat from formation still being let off), Neptune has high speed winds driven by internal heat, axis is tilted by about 29 degrees to its orbit (similar obliquity to Saturn), greater density indicates large rocky core which is surrounded by a layer of water then atmosphere of H + He,

main sequence stars

90% of all stars are this type, Our sun is this type, V, .08-100 are the range of solar masses on (blank), to get a star to the (blank) line it had to go through giant molecular cloud-> portion collapses and shock wave goes through-> becomes egg-> protostar forms surrounded by cocoon nebulae-> star begins generating gamma ray photons in core ->contraction stops when outward pressure meets inward gravity force, (blank) with masses up to 4 solar masses can end up as white dwarfs only if they lose mass during the red giant and planetary nebula phases, otherwise they exceed the chandrasekhar limit,

Venus's atmosphere

96% CO2, 3.5% N2, small amounts of water/sulfuric acid/hydrochloric acid, upper atm is very windy w/ winds reaching 350 km/hr but go to 0 km/hr near surface, atm pressure on surface is about 90x that on Earth's surface, surface temps measured at about 860 degrees F, Mercury lost hydrogen and helium the same way earth did in its early formation but Venus retained everything else, atm is so thick bc its closer to sun than earth, prensence of sulfuric acid in clouds which Pioneer Venus found in 1978 were prob from volcanic interruption,

Harlow Shapley

American astronomer in 1917 worked at Mt. Wilson observatory to determine distances to what he thought were globular clusters of Cepheid variables but his work led to a period-luminosity diagram for RR Lyrae variables, used Mt. Wilson observatory, he used Henrietta Leavitt's discovery of the Cepheid variable's period-luminosity relationship, studied a total of 117 globular clusters for which he determined distances and directions relative to our solar system, showed that the globular clusters were distributed about a point located thousands of light-years from the Sun, his discovery also showed that the Galaxy is larger than Herschel/ Kapteyn imagined and (blank) moved it from the center of the universe--> considered the 20th cent equivalent modern of Copernicus (moved from geocentric to heliocentric model) ,

James W. Christy

American astronomer who in 1978 discovered that Pluto has a moon (Charon) which disproves Pluto was once a moon, dad of former USC grad,

Daniel M. Popper

American astronomer who made many of mass measurements of stars, after he knew mass he knew luminosity, made the Mass-luminosity diagram, 1st person to measure the gravitational redshift of photons for a white dwarf star in 1954-- which is an experimental test of general relativity

Bernard Burke

Guy who Wilson and Penzias told about background radiation, (blank) but these two in touch with Dicke who told them of the importance of their discovery,

stellar parallax

Aristotle and Brahe couldn't detect (blank) so they concluded Earth was stationary, first measurements of (blank) were made by Friedrich Bessel in 1838 who was 1st and used star 61 Cygni, Thomas Henderson and Freidrich Struve made them independently, used (blank) to get distance measurements in early 20th century but only know a few parallax angles correctly--> today we use absolute magnitude to infer distance,

Main Sequence Life (stellar maturity)

As a star ages on the main sequence, it becomes more luminous and cooler, the number of nuclei decrease with time due to fusion, the core shrinks (is only in core bc fusion takes place here) to sustain smaller # of particles, gravitational potential energy is liberated and heats then core, fusion rate increases, additional energy is released by the core, the star becomes more luminous bc more gamma ray photons are present so energy is transferred to the radiative zone & the outer portions of the star expand, the star's surface cools, (blank) is happening to the Sun right now bc it has been in (blank) for 4.6 billion years and is becoming more luminous and cooler, when our sun uses up the hydrogen in the core it will quickly expand and cool, it cools because as a gas expands it cools, objects having more than .08 solar masses are (blank), if we want to find life in other solar systems we should look for cooler lower mass stars than the sun,

Georges Lemaitre

Belgian cosmotologist who was 1st to propose a model for Big Bang, he wrongly thought one primeval atom fragmented into many pieces and that the cosmic rays were the radiation from the Big Bang (wrong)

Laser Interferometric Gravitational Wave Observatory (LIGO)

Caltech and M.I.T are now testing a pair of giant Michelson Interferometers which are designed to search for evidence of the gravitational waves which are predicted to exist in the theories of general relativity, these 2 are both buried in the earth (one in Washington and one in Louisiana)

Maarten Schmidt

Caltech astronomer who in 1963 showed the highly redshifted hydrogen lines in quasars 3C 273 and 3C 48, unlike these 2 most quasars aren't the sources of radio waves,

solar corona

Can only see during total solar eclipse, lies above transition zone, temps can vary from 600,000 K to about 10,000,000 K directly above solar active regions for brief periods of time, spectral line emission happens here

solar layers

Core-> radiation zone-> convection zone-> photosphere-> chromosphere-> transition zone-> corona-> solar wind

Clyde Tombaugh

Discovered Pluto at Lowell observatory in 1930, used blink comparator to compare two photos of sky taken a few days apart--> moving object will appear to jump,

Walter Baade

During WWII the outside lights in the city of LA were turned off each night and all windows covered to prevent possible attackers from seeing the inside lights, which allowed German astronomer (blank) to use the 100 in. Mt. Wilson telescope to develop the notion that there are multiple stellar populations in our Galaxy,

Planck Epoch

During the first 10^-43 second after the onset of the Big Bang something caused the spacetime filled by this scalar field to begin to expand---> expansion began a series of brief epochs in which we eventually ended up with the universe as we now know it, at the end of the Planck Epoch the force of gravity became decoupled from the other three forces of nature

Jan Oort

Dutch who in 1950 proposed that a comet cloud exists in a spherical shell between 10,000 and 100,000 AU from the planetary part of the solar system, (blank) along with Lindblad used patterns of velocities of stars to show that the center of the Galaxy is thousands of light-years away in the direction of Sagittarius,

Einstein's Static Model

Einstein couldn't understand why the universe (filled with mutually attracting matter) hadn't collapsed in upon itself--> adjusted his theory in ad hoc manner to insure that it would neither collapse on itself nor expand... did this by introducing Cosmological Constant of + value

E=MC^2

Einstein's famous equation which claims all matter and energy are equivalent, M=rest mass of particle C=speed of light E=equivalent energy, (blank) is responsible for energy source of all stars, in a paper in 1905 Einstein went on to claim that all matter and energy are equivalent, it is this equation which is responsible for the energy source of all main sequence stars

Grindstone Model of Milky Way

England had many mills with grindstones in them in 1780s, Herschel's model for milky way, looked like a gator, white dots were locations of globular star clusters,

Key Theoretical Ideas of Cosmology

Equivalence of mass and energy, notion of 4-D spacetime also from special relativity 1905, notion of curvature of spacetime by matter from the general theory of relativity (gravity is a curvature of spacetime) in 1915, existence of solutions to the equations of general relativity which are expanding, notion that an extremely high density of matter could exist in the early universe, idea that particles of matter could form spontaneously from quantum fluctuations of a pre-existing energy field, the pairs of particles are called "virtual" particles because we cannot observe them since they last for too little time to be seen, idea that quarks and leptons are the most elementary of particles, idea that the four forces of nature, which are the strong nuclear force, the electromagnetic force, the weak nuclear force, and the gravitational force, were all once unified into a single force, idea of "phase transitions,"

flat universe

Friedmann flat model, has to have just right density to be flat, is the borderline case between the open and closed models, in a (blank) gravity just balances its expansion so that it stops expanding only in an infinite amount of time in the future,

M2001

H-R diagram was done of this cluster and was originally called M007 (James Bond movie reference in 1960s begins), then was renamed after 2001 Space Odyssey movie, is an artificial cluster,

Sun

G2 star in main sequence phase of life--> G2V star, surface temp is about 5800 Kelvin on avg, 4.6 billion years old, in 5 billion years (blank) will become a red giant bc such mass main sequence as (blank) need about 10 bill years before red giant phase --> vaporize Earth and other terrestrial planets--> (blank) shrinks from red giant and becomes white dwarf of size of Earth but dense ball of very hot gas but bc its small it won't warm solar system, avg. angular diameter is about .5 degree (same as moon),larger than 95% of stars in our portion of Milky Way Galaxy, (blank)'s avg density is about 1.41 g/cm^3 which is about same as Jupiter, rotates once every 25.4 days at equator and once every 35 days near poles (differential rotation) which consists to about 30% of outer solar interior, star, contains 99.85% of mass in solar system, each planet revolves eastward around the sun, (blank) is about 10x diameter of jupiter and 109x that of Earth and could hold over 1,300,000 Earths, mass of (blank) is about 330,000 x mass of Earth, (blank) is about 73% hydrogen, 25% helium, and 2% for all other elements, when it uses up all hydrogen it will become red giant, we use x-rays to image the (blank) from earth-orbiting satellites which isn't like taking a picture but making an image of solar corona

Ganymede

Galilean moon, largest moon in solar system (larger than Mercury), less active, darker surface than Io or Europa,

Cassini's division

Gap in between Saturn's two groups of rings, Cassini spacecraft is still in orbit around Saturn, the gravity of Mimas (moon of saturn) acts synchronously on the orbital path of nearby ring particles, mimas tugged particles away from planet to outer ring outside gap (example of resonance phenomenon)

differential rotation

Gas giants exhibit diff periods of rotation at diff latitudes, the Sun also exhibits this, (poles or equator will rotate faster), because their crusts aren't solid like earth, leads to swirling at boundaries

Alfred Wegener

German meteorologist, credited with developing the idea of continental drift in 1910, studied plate tectonics but was rejected by Earth scientists at first, plate tectonics was first believed in 1960s

Hubble constant

H0, is the proportionality constant in Hubble law, it is the ratio of recessional velocities of galaxies to their distances, determining a precise value for the (blank) is difficult because accurate measurements of distant galaxies are hard to obtain

Annie Jump Cannon

Harvard astronomer, developed methods for determining a star's spectral classification from an examination of its spectrum, realized original sequence of Secchi's spectral classifications were wrong, determined spectral types for more than 500,000 stars, led Harvard College Observatory's program of using "female" computers to carry out tedious long hand computations that were necessary in astrophysics,

Hubble Classifications of Galaxy Types

Hubble divided galaxies into normal and abnormal galaxies, He found that most galaxies appeared to have a normal shape, but he found others which had strange appearances and he called them abnormal, we do not believe that galaxies evolve from one shape to a different shape except in clusters of galaxies where some spiral galaxies may be captured by large elliptical galaxies and may disappear in the process, bc of great distances galaxies exhibit no proper motion, evidence of past collisions has to come from present appearance, when galaxies collide gas and dust clouds interact but there are few collisions between individual stars, sometimes two galaxies may merge or sometimes a larger will cannibalize a smaller,

H

Hydrogen

Milankovich effect

Ice Ages were caused by small changes in the obliquity of Earth's spin axis and by small changes in the eccentricity (shape) of the Earth's orbit, there have also been other rapid climate changes which cannot be due to this effect (global warming)

Detecting Stellar Mass in Black Holes

If a black hole and red giant or supergiant form a binary system, material will be pulled from the giant and will swirl around the black hole, causing X-Rays to be released from the heated material in the disk,

Purcell and Ewen

In 1951, (blank) used a specially built radio telescope to detect radiation emitted by interstellar neutral hydrogen which emits radiation in the radio portion of the e/m spectrum,

Inflationary model/ scenario

In March of 2014 a team of astronomers based at the Harvard-Smithsonian Center for Astrophysics announced that data they had obtained from the BICEP2 microwave telescope close to the South Pole showed a pattern in the polarization of the Cosmic Microwave Background that they claimed was evidence for both the Inflationary Model of the Big Bang and also for the presence of gravitational waves that were generated during the Inflationary Epoch. If this claim turns out to be verified, it will very likely lead to another Nobel Prize in Physics.

Giovanni Dominico Cassini/Jean Dominique Cassini

Italian who discovered gap in rings of saturn and saw great red spot, discovered gap in rings of saturn

Yucatan peninsula

KT Event, 10 km diameter struck yucatan peninsula and led to extinction of many species of dinosaurs

Olympus Mons

Largest volcano on Mars, height is about 24 km (2x size of Earth's largest mountain), Mars can grow larger volcanoes than Earth because it lacks tectonic plates, volcanos can grow to huge sizes if they don't move off the hotspot, Earth's crustal motion moves a volcano before such a large volcano can form, it may lack tectonic plates because it cooled so quickly the crust became too thick and strong to be broken into pieces but striped magnetic field pattern could indicate tectonic activity

Origin of Short-Period Comets

Long period comets sometimes become short-period comets through the combined gravitational influence of Jupiter or Saturn and the Sun, most comet orbits are elliptical or parabolic,

Massive O and B type stars

May spend only 100,000 years as protostars before joining the main sequence, most massive stars reach main sequence more rapidly, blow material out at supersonic speeds during the time just before joining the main sequence, a star with a mass greater than 100 solar masses will emit radiation so intense that it will prevent more material from falling into the star, thereby limiting the star's size

Planet Summaries (Quick)

Mercury: most moonlike bc of surface and lack of atm, Mercury M for Moon, Venus: hot hellish planet, love is hot and fiery like goddess of love, Earth: just right home planet Mars: the red planet Jupiter: the colorful planet Saturn: the ring planet Uranus: the tilted planet, sitting on it's anus Neptune: blue planet, God of Sea->blue

Doppler Method

Method used to measure radial velocity of planets by measuring doppler shift in spectral lines of star light, toward observer is blue, away from observer is red, star's color doesn't change, allows us to discover extra solar planets , detected huge/ gas giant planets where terrestrial planets SHOULD be, preferentially discovered more massive planets because of the nature of the method that would more easily detect larger gas giant planets, since 1995 this (blank) has found evidence of planets orbiting wiggling stars such as 51 Pegasi, 70 Virginis, and 47 Ursae Majoris, (blank) measures blue shift and red shift

Pluto Express

NASA's spacecraft which plans to fly past Pluto and its moons in 2014/2015(should send back first info on this planet)

Dawn

NASAs spacecraft which went into orbit around Vesta in 2011, and will be orbiting Ceres after

Kepler space probe

NASA's Kepler space probe which has found over 3000 candidate planets, can't work anymore bc of telescope

Phoenix Lander

NASA's Mars Polar lander, response to previous lander that blew up due to bad measurements, discovered frozen ice and perchlorates in soil beneath--> mars could support plant life if oxygen were in atm, landed near north polar cap of Mars in May of 2008,

Curiosity

Nasa's Mars science lab, landed on Mars on August 5th, to begin search of evidence of conditions suitable for life in past, discovered water, sulfur, and chlorine compounds in Martian soil in 2012 but could have been tracked from Earth, this mission was successful--> new lander to Mars in 2020 to collect rocks

Triton

Neptune holds his (blank) under the sea, one of Neptune's moons, only large moon that revolves around central planet in retrograde direction, will crash in Neptune in future, has an atm, light surface w/ water ice mixed w/ nitrogen & methane frost, geyser type nitrogen volcanoes due to internal heating from tidal forces caused by Neptune's gravity, surface resembles cantaloupe but appears young with few craters, fault lines in frozen soil, streaks of nitrogen on surface, one of 7 largest planetary moons, experiences tidal forces from Neptune's gravity--> contraction--> heat--> active volcanos

NGC

New General Catalog

Mass of the Galaxy

Oort and Lindblad discovered in 1927 that the Galaxy in the Sun's neighborhood undergoes differential rotation--> mass of inner galaxy is estimated at 110 billion solar masses and new research indicates that the total mass of the Galaxy is about 10^12 solar masses (10 times more mass than calculated for the inner Galaxy),

The Moons of mars

Phobos and Deimos (fear and panic), shaped like potatoes bc gravity was too small/nonexistent for them to form into spheres, long, tiny, probably captured asteroids--> which are usually non spherical

dwarf planet

Pluto is was classified from a planet to a (blank),

Mt. Wilson 60-Foot Solar Tower

Rhodes' research group conducts such helioseismic search using both (blank) and a space experiment which was recently flying on the NASA/ ESA solar and heliospheric observatory (SOHO) spacecraft,

Alexander Friedmann

Russian mathematician who first made use of general relativity in cosmology, didn't care that no one had observed that the universe was expanding and he created models that did expand , in (blank)'s models there were three possible geometries that spacetime could have: closed, flat, and open, all 3 of the Friedmann models are < Hubble Time (Tsub0= Hubble time= maximum possible age of the universe), the models are used to plot past and future changes in the size of the Universe

Milutin Milankovich

Serbian scientist argued the Milankovich Effect that Ice Ages were caused by small changes in the obliquity of Earth's spin axis and by small changes in the eccentricity (shape) of the Earth's orbit

Exploration of Mars

Spirit, Opportunity, Phoenix Lander, Curiosity, studying mars may tell us more about Earth's history and what awaits us, Mars pathfinder w/ sojourner landed in 1997 and began exploring surface,

Solar Oscillations

Sun constantly oscillates/ vibrates, is filled w/ waves which are trapped sound waves, acoustic waves are similar to waves that occur in organ pipes, (blank) were discovered in early 1960s using MWO 60 ft solar tower, their predominant period is 5 mins, by making comparisons between predicted and observed oscillation frequencies we can probe the internal structure of Sun, Rhodes found that solar convection zone is much deeper than people used to think it was, frequencies of (blank) change during each solar cycle as level of solar activity changes, Rhodes found that it is possible to measure rotation rate of sun by comparing frequencies of waves that are traveling in opposite directions around solar surface, we are able to probe how rapidly the diff parts of solar interior rotate, (blank) occur constantly bc of convection zone,

perigee

The largest apparent size of the Moon, bc Moon is closest to Earth in it's orbit at this time

magnetosphere

The region of interplanetary space surrounding the Earth in which the geomagnetic field dominates the interplanetary magnetic field (which in turn originates in the solar corona) is called the earth's (blank), we think the magnetic field originates beneath our feet in the Earth's molten outer core, this field extends into interplanetary space, is approximately spherical on one side of the earth but is stretched on the other, most other planets have magnetosphere, contains Van Allen belts--> 2 donut shaped regions of charged protons and electrons emitted by Sun and captured by Earth's (blank), discovered by James Van Allen in 1958

apogee

The smallest apparent size of the moon bc Moon is farthest from Earth in it's orbit at this time, one sidereal period is about 1 month (27.3 days),

Spirit and Opportunity

Two Mars Exploration Rovers, were only supposed to last 90 days, landed in January of 2004, one stopped in 2012 the other still works, detected evidence of standing and flowing water in past

Karl Schwarzschild

U.S. astrophysicist who was 1st to point out that there was a solution to one of Einstein's field Equations in his Theory of Gen Relativity which has a singularity as one possible solution

John Wheeler

U.S. physicist 1st to employ term black hole

Fred Whipple

US astronomer who proposed in 1950 that the nucleus of a comet is essentially a dirty snowball made up of water ice, frozen carbon dioxide, small solid grains,

black holes

US physicist John Wheeler was 1st to employ the term "(blank)", (blank) are collapsed stars, can be result of Type II Supernovae of a heavyweight, bc such core has a mass greater than 3 solar masses and it swallows itself as a (blank) after supernova occurs, the U.S. astrophysicist Karl Schwarzschild was 1st to point out that there was a solution to one of Einstein's Field Equations in his Theory of General Relativity which has a singularity as one possible solution, in his honor the radius of a black hole's event horizon is now called the Schwarzschild radius, neutron degeneracy cannot support a neutron star whose mass is greater than about 3 solar masses, (blank) is an object whose escape velocity exceeds the speed of light and therefore whose radius is equal to or less than the Schwarzschild radius, the density of (blank) is inversely proportional to its mass, as long as the radius of a collapsing star is greater than the Schwarzschild radius the star is not considered to be a (blank), once its radius is equal to the Schwarzschild radius the star is said to have become a (blank) and it will remain a (blank) even when its radius shrinks to become smaller than the size of the event horizon,

Linda Morabito

USC astronomy major at JPL who discovered volcanoes on Io the Galilean moon closest to Jupiter w/ volcanic geysers that spew hot sulfur on surface, Io's heat is produced by tidal forces caused by its eccentric orbit around Jupiter

Vensra 7

USSR, 1970, first to land on planet (Venus)

T Tauri Stars

a certain class of young stars that show rapid and erratic changes in brightness in the form of enormous flares, said flares are thought to play a part in blowing away the cocoons of newly forming stars, particularly K- and M-type stars,

Volatile element

a chemical element that exists in a gaseous state at a relatively low temp

nebula

a cloud is called a (blank) if it is dense enough or bright enough to show up in a photograph, cometary knots (having nothing to do with comets) are found in some (blank)

sublimation

When polar caps (consisting of water ice base covered during the winter by Co2) shrink the Co2 (blank) into the Martian atm, it doesn't melt it goes from solid to gas, when you put dry ice in party punch is sublimes (doesn't melt just goes straight from solid to gas)

dark nebula

a cloud of interstellar dust that blocks light from stars on the other side of it

Supernovae

a (blank) attains a magnitude of -19 (10 billion Suns), there are 2 major types (Type I: no prominent lines of hydrogen seen in their spectra & Type II: contains prominent hydrogen lines; results from explosion of single star,

active galaxy (AGNs)

a (blank) is a galaxy with an unusually luminous nucleus, because the energy of an active galaxy comes from its nucleus astronomers often refer to active galactic nuclei rather than (blank), Seyfert and N galaxies are (blanks), the tremendous energy that comes from (blank) and quasars is caused by an immense black hole at the nucleus of the galaxy, the black hole is surrounded by an accretion disk heated by infalling material that in turn radiates energy mostly in the form of X-rays, current theory holds that the diff types of (blank) we see are basically the same and only appear different depending on their orientation w/ respect to us, some (blank) contain BL Lac objects (very luminous nuclei)

synodic revolution

a (blank) of the Moon takes about 29.5 days aka one lunar month/ synodic period/ lunation/

closed universe/ spacetime model

a (blank) universe is one in which parallel lines will eventually close back upon themselves, it makes use of Riemannian geometry, such a universe will eventually stop its current expansion and will eventually collapse back in upon itself, one of the three possible geometries Friedmann said spacetime could have

Properties of Black Holes

a black hole can be described by its mass, electric charge, and angular momentum, are thought to spin very rapidly, Steven Hawking claimed that black holes might disappear or evaporate when the particles inside them would meet anti-particles from the outside universe, Hawking also said that angular momentum can be removed from a spinning black hole even though no mass can escape from it, and he claimed that out entire Universe might be viewed as one gigantic black hole,

pulsar

a compact object that emits regular radio waves, doppler measurements confirm a companion orbiting a (blank), lighthouse model explains that rapidly rotating neutron star whose beam of radiation is only seen as it sweeps the Earth, neutron stars that forms when middle mass stars supernova, either a supernova doesn't destroy all planets around star or the act of exploding creates forces that ends up forming planets where there weren't any before, a (blank) is a celestial object of small angular size that emits pulses of radio waves with a regular period between about .03 and 5 seconds, objects that emit pulsing signals with a duration of .001 second cannot have a diameter any greater than .001 light-seconds, which is a few hundred km, such a small size ruled out white dwarfs (earth-sized objects), leaving the hypothesized neutron star as the explanation for pulsars, a (blanks) extremely strong magnetic field causes a beam of radiation to be emitted near each magnetic pole of the pulsar, the (blanks) rapid rotation causes the beam to sweep through space in a very short period, the narrow beam of radio frequency radiation is caused by a process of synchrotron radiation in which electrons traveling near the speed of light spiral around the pulsar's intense magnetic field lines,

Masses of Galaxies

a galaxy's mass can be determined by observing the rotation periods of some parts of it (using Doppler shift data) and then applying Kepler's law, another method is to use a pair of galaxies revolving around each other, the problem with this is that its difficult to determine the angle of the plane of revolution to our line of sight, 3rd method of measuring uses clustering of galaxies, the cluster method gives mass values for clusters that are much greater than is accounted for by the visible stars within the galaxies in the cluster for the milky way we can only account for 1/10th the total mass of the galaxy--> missing mass is the difference between the mass of clusters of galaxies as calculated from Keplerian motions and the amount of visible mass seen in photos,

light curve

a graph of the numerical measure of the light received from a star versus time

galactic rotation curve

a graph of the orbital speed of objects in the galactic disk as a function of their distance from the center, one for milky way indicates that large amounts of mass orbit the center far beyond the Sun's orbit

galactic (open) cluster

a group of a relatively small number of stars that share a common origin and which are located relatively close to one another, you can see space between the stars,

supercluster

a group of clusters of galaxies, the space between the (blanks) appears to consist of great voids which contain few or no galaxies, the galaxies lie on the surfaces of large bubbles

Lightweight stars

a group which includes the Sun, stars with masses between .4 and 2 solar masses, unlike flyweights, (blank) are not fully convective in their interiors-> they don't use up all of their hydrogen fuel supply; only the hydrogen in their cores is used up on the main sequence, about 90% of the stars in sky are in main sequence phase of their lives today, for most of these stars the next step after leaving the main sequence is to become a red giant, a typical star begins to contract (just the core) once its core is depleted of hydrogen, the gravitational contraction causes the star to heat up (just the core)--> heats shell of gas surrounding the core to high enough temps that the fusion of hydrogen can begin there, these 2 sources of energy cause the outer portions of the star to expand and cool (as per the gas laws), the star moves to the right on the H-R diagram and upward due to increasing luminosity, red giants can have a lower surface temp (less radiation per square meter) but a higher luminosity bc its diameter will have expanded 200 x or more, the core of a red giant consists of helium nuclei intermingled with electrons (similar to a regular gas), when the core temp reaches 100 million kelvin degrees,helium nuclei begin to combine, forming carbon, the helium flash is the runaway helium fusion reaction that occurs during the evolution of a red giant, following the helium flash the star forms 4 layers 1) an inner degenerate carbon core 2) a layer of helium that fuses to carbon in a conventional manner 3) an outer hydrogen-fusing shell 4) an outer layer below 10 million Kelvin in temp where no fusion can take place and the red giant star then expands further

Caloris Basin

a large "bulls-eye" impact crater visible on Mercury, suggested that the object that created (blank) was very dense and its presence under Mercury's surface caused the planet to be lopsided--> spin-orbit coupling resulted, had the object been larger mercury might not exist today,

binary star system

a pair of stars that are gravitationally linked so that they orbit one another (bc they had angular momentum when they were formed and if they stopped they would slide into each other bc of attraction) and were formed side by side, they move around a common center of mass (barycenter) and unseen planets make stars wiggle around center of mass, the method of observing the wobbles is called Astrometric method for detecting Extra-Solar Planets, a star exhibiting discernable motion toward and away from Earth can be evidence of an unseen planets, there are also triple star systems, double-double star systems and sextuple systems, the conservation of angular momentum stops gravity from working to bring the stars together, (blank) are important to us bc they allow us to measure the masses of the stars w/ Newton's version of Kepler's 3rd law, knowing the size of one of the star's ellipses (Savary proved elliptical orbits in 1827) and the period of its motion allows calculation of the total mass of the two stars, to determine how this mass is distributed among the 2 stars we need to measure the ratio of the two stars' distances to the center of mass but exact mass calculations cannot be done bc the inclination of spectroscopic (blank) orbits are usually not known but we assume an avg inclination and get info about avg masses of such (blank), a visual binary is a true (blank) while an optical binary is a false (blank) and only appears so bc of small angular separation, two stars speed up at perihelion and slow down at aphelion (because of conservation of angular momentum)---> red shift and blue shift invert so we can observe spectra and witness wavelength shifting to detect (blank) even if we can't see one of the stars, a radial velocity curve to plot radial velocity of (blank) as a function of time w/ coinciding spectral lines reveals the period and barycenter of binary-- the curve also reveals the elliptical nature of the orbits of (blank) proved by Felix Savary in 1827, a close (blank) will affect the shape of the stars bc gravity is so strong at such a strong distance and light curves will flatten out, types of binaries: fake (optical), visual, spectroscopic, double lined spectroscopic, single lined spectroscopic, eclipsing, astrometric, close --> novae,

rift zone

a place where tectonic plates are being pushed apart, normally by molten material being forced up out of the mantle, one of these (blanks) runs down the spine of undersea mountain range located 1/2 way between Europe and US and between Africa and South America --> mid atlantic ridge which is hot w/ earthquakes and proved Wegener's theory of 12 plate tectonics

singularity

a point of infinite density and zero volume

accretion disk

a rotating disk of gas orbiting a star, formed by material falling toward the star, the hydrogen build-up on the surface of the white dwarf can ignite into an explosive fusion reaction that blows off a shell of gas, though this shell contains a tiny amount of mass (.0001 Msun) it can cause the white dwarf to brighten by 10 magnitudes (10,000 times) in a few days,

Model for Sunspot Cycle

a solar maximum most spots occur about 35 degrees north or south of the equator--> cycle progresses and spots are seen closer and closer to Sun's equator--> spots reach equator and cycle is at a minimum and begins again, the (blank) ranges from 7-17 years in length and diff (blank)s have diff lengths and diff peak sunspot #s, we are currently in Cycle 24 which is much weaker than 23 and scientists predict sunspots may disappear in 2030s, frequencies of solar oscillations change during each solar cycle as the level of solar activity changes,

globular star cluster

a spherical group of up to hundreds of thousands of stars found primarily in the halo of the galaxy, could be 1/2 a lightyear apart but we can't see space through them, stars in region of the Sun avg 4-5 ly apart, are important bc they have same compositions and ages --used in H-R diagrams, could have 400-5,000 stars in them (more than galactic), think of (blank) as electrons orbiting nucleus, 70% of stars are population II with 1/20th the avg heavy-element content of the sun, provide convenient ways of measuring age, youngest stars in (blank) are about 11 billion years old and oldest are between 12 and 13.7 billion

planetary nebula

a spherical shell of gas that is expelled by a red giant near the end of its life, the material in the shell glows because UV radiation from the central hot star causes it to fluoresce, pulsations and/or stellar winds are thought to cause planetary nebulae, gas that was part of outer enevelop of star with enough kinetic energy to leave the star behind by

protostars

a star in the process of formation before it reaches the main sequence which forms from an egg, a (blank)'s energy source is gravitational potential energy, it comes from the infall of its gas toward its center, a (blank) doesn't have high enough gas pressure to offset and balance gravity which is forcing everything inside because gravity is only an attractive force, as (blank) shrinks it gets hotter emits more radiation and gradually blows away the outer portion of its cocoon, (blank) with masses of less than .08 solar masses do not have enough internal pressure to ignite hydrogen fusion to become main sequence, recent infrared observations reveal that (blank) are commonly surrounded by disks of gas and dust that fit well with the theory of formation of the solar system, streams of material have been observed flowing from the poles of (blank)--reducing the angular momentum of (blank), (blank) form in the head of stalks, the whole (blank) spins bc the cloud it formed out of was spinning and streams of material have been observed flowing from the poles of (blank) which would help reduce angular momentum,

supergiant stars

a star of very great luminosity and size and may be several hundred times larger in diameter than the sun, Betelgeuse in Orion is an example of a red (blank), because of greater core temps and pressures, (blank) produce heavier element nuclei, such as neon, silicon, and iron, the sizes of a few of (blank) have been measured using interferometry (Mt. Wilson has such an instrument), a star with a mass greater than 100 solar masses will emit radiation so intense that it will prevent more material from falling into the star, thereby limiting the star's size, (blank) expand from heavyweights,

nova

a star that suddenly and temporarily brightens, thought to be due to new material being deposited on the surface of a white dwarf, because so little mass is blown off during a (blank) the explosion does not disrupt the binary system, ignition of the infalling hydrogen can recur again with periods ranging from months to thousands of years, the chevy car named (blank) but the ford pinto actually exploded, (blank) may reach an absolute magnitude of -8 (100,000 Suns), a CLOSE binary system consisting of a white dwarf and a newly formed red giant will result in the formation of an accretion disk around the white dwarf (evolved faster bc it has more mass), a (blank) may reach an absolute magnitude of -8 (about 100,000 Suns), (any one of other kinds of binaries can also be this close kind, 2-4 times avg diameter apart), mutual gravitational attraction can effect evolution of other star, spiraling disk of gas around white dwarf (mass transfer), 4 diff types of close binaries: 1) Surfaces don't reach surface- detached 2) One surface reaches limit - semi-detached 3) Both surfaces just reach roche limit- contact 4) Both surfaces exceed limit - overcontact, we observe light curves to look at what happens with close binaries,

Titius and Bode's Law

a theory from the past that was used to explain the pattern of spacing of the planets but is now known to have no physical cause, helped to locate Ceres bc of gap,

Rene Descartes's whirlpool or vortex theory -> evolutionary theories

a theory proposed in 1644 to explain evolutionary formation of solar system, all other evolution theories have their start with this one, was modified by Immanuel Kant in 1755 with Newtonian mechanics, and Pierre Simon Laplace in 1796--> modified vortex into a rotating cloud of gas that was contracting under its own gravity into a flattened disk, the rotating contracting disk of gas should speed up according to the law of conservation of angular momentum, and the sun-the center of the former rotating cloud- should be rotating much faster than it is observed to be, the total angular momentum of planets is greater than that of the sun but this shouldn't occur according to Newton's laws--> (blank) theory lost credibility in early 20th century but Sun's slow rotation rate can now be explained by magnetic braking

lunar month

a time interval which is the length of 29.5, or one synodic revolution

N galaxies

a type of abnormal active galaxy, is an active galaxy with an unusually luminous nucleus, have even brighter nuclei than Seyfert

Seyfert galaxies

a type of abnormal active galaxy, is one of a class of spiral galaxies having active nuclei and spectra containing emisson lines, is an active galaxy w/ unusually luminous nucleus

peculiar galaxies

a type of abnormal galaxy which Hubble defined as having an abnormal shape which suggests that either explosions have occurred in them or that they are the result of a collision between two otherwise normal galaxies

Kepler's 3rd Law as Re-derived by Sir Isaac Newton

a^3/p^2=K(m1 + m2), used to measure estimates for mass of sun with several diff planets, we find the mass of these planets by calculating distances and periods of revolution of these planets' natural satellites (only 7 out of 9 planets possess satellites--Mercury and Venus do not so we had to wait for orbiting space probes to determine mass), binary stars are important bc they allow us to measure masses of stars w/ (blank) but we generally only get the TOTAL mass through knowledge of one of the star's ellipses along w/ knowledge of the period of its motion,

resonance

adding energy to an object once per period,

symbiotic binary

affect each others evolution, consists of red giant and white dwarf, nova outbursts occur bc helium is fused at the surface causing outburst bc enough matter was transferred to the surface of the white dwarf,

minor planets

aka asteroids, Ceres, Pallas, Vesta,

chromosphere

aka color sphere, rarely see it except for total solar eclipse, bright red in color seen peeking from mountains on moon, region of solar atm approx 2,000 to 3,000 km thick that lies between photosphere and corona, sun's temp reaches minimum value in (blank) at 4,200 degrees

Era of Nucleosynthesis

aka the Big Freeze-Out, time interval between 1 and 100 seconds after the initiation of the Big Bang, almost all of our current helium, deuterium, and some lithium nuclei were created in a series of nuclear reactions during (blank), by 100 seconds after the start of the Big Bang the universe had expanded so much that its temperature had dropped to the point where the photons of energy split apart the protons and neutrons which had combined to form the nuclei of helium, deuterium, and lithium, by 100 secs after all of the neutrons had gone into the formation of these nuclei,

planetary motions

all planetary orbits are ellipses but all except mercury and pluto are nearly circular, each planet revolves around Sun in same direction (eastward), all planets rotate in counterclockwise direction, except Venus/Uranus/Pluto rotate retrograde, the right hand rule tells us orbital/ revolving/rotating directions of planets, most satellites also revolve planets in counterclockwise direction but retrograde orbiting moons are probably captured asteroids, pluto and mercury have 1st and 2nd most tilted elliptical paths,

Thomas Harriott

along with Galileo, were first Europeans to report sunspots in 17th cent,

Thomas Henderson

also early detector of stellar parallax with Bessel and Struve

Friedrich Struve

also early detector of stellar parallax with Henderson

universality

an assumption in cosmology which says that the universe obeys the same physical laws everywhere

total solar eclipse

an eclipse in which light from the normally visible portion the Sun (the photosphere) is completely blocked by the Moon, most complicated path of moon through earth's shadow, happens when sun moon and earth are in one straight line (syzygy), can only be seen totally on solar eclipse paths

annular solar eclipse

an eclipse in which the Moon is located too far from the Earth for its disk to completely cover that of the Sun and the outer edge of the Sun is seen as a bright ring or annulus

lunar eclipse

an eclipse in which the Moon passes into the shadow of the Earth, a lunar eclipse doesn't occur at each full moon because the plane of revolution of the moon is tilted 5 degrees compared to the plane of the Earth's revolution around the Sun, the moon is being eclipsed and the earth is doing the eclipsing, the lunar orbit precesses so we have the moon sometimes in Earth's shadow (the line of sight where we can have new and full moon is constantly moving) the moon's orbit is constantly precessing, to have a lunar eclipse the moon must be at one end or the other of the line of nodes during new or full phase

partial lunar eclipse

an eclipse of the Moon in which only a portion of the Moon passes through the umbra of the Earth's shadow, this will be a portion of the entire eclipse, Its called partial when only a portion of the moon is in the umbra

total lunar eclipse

an eclipse of the Moon in which the Moon is completely in the umbra of the Earth's shadow for a portion of the eclipse, one occurred Feb 22nd, 2008, a total eclipse of the Moon is never totally dark because some (red) light is refracted toward the Moon by the Earth's atmosphere. most of the refracted light reaching the Moon is red; the blue portion has been scattered out of the beam by particles in the atmosphere

penumbral lunar eclipse

an eclipse of the Moon in which the Moon passes through the Earth's penumbra but not any part of its umbra, one occured Feb 9th, 2009,

solar eclipse

an eclipse of the Sun in which light from the Sun is blocked by the Moon, we can only have it when moon is in new

nonvolatile element

an element that is gaseous only at a high temp and condenses to a liquid or solid when the temp decreases

Valles Marineris

an enormous canyon on Mars that stretches nearly 4,800 km in length, 3,000 miles,

seismology

analyzing travel times of two types of waves generated by earthquakes which allows us to find out info on Earth's interior

Proper Motion

angle through which a star moves each year, its angular velocity a seen from Sun, Barnard's star, the 2nd closest star to Sun, exhibits the greatest (blank) of any star -- 10.25 arcseconds/year

spin-orbit coupling

an example of this is shown by the rotational and orbital periods of the Moon are exactly equal (because of the tidal pull of the Earth on the Moon), one orbital period for the Moon=one sidereal revolution (27.33 days), Mercury also shows example of (blank)

astrometric binary

an orbiting pair of stars in which wiggles in the proper motion of one of the stars reveals the presence of another, can't tell its a visual binary bc secondary star is too bright or too small to be seen,

spectroscopic binary

an orbiting pair of stars that can be distinguished as two due to the changing Doppler shifts (redshift and blue shift causes spectral line shifting) in their spectra, 1st such binary was discovered by E.C. Pickering in 1889, bc the inclination of (blank) orbits are usually not known, exact mass calculations cannot be done with the total mass/ knowledge of one of star's ellipses/ period, but by assuming an avg. inclination awe can get information about the avg masses of such binary stars,

visual binary

an orbiting pair of stars that can be resolved (normally with a telescope) as 2 stars, about 10% of stars in sky are visual binaries with a telescope, can be confirmed by observing over long time and looking for signs of revolution, (blank)= true binary/ binary star system

Supermassive Black Holes

another class of black hole which contains the mass of several hundred thousand or a few million stars, such black holes are known as (blank) they are thought to exist in the nuclear regions of many galaxies including our own, in addition to a black hole which contain the mass of a single large star, In June of 2012 NASA launched the Nuclear Spectroscopic Telescope Array (NuSTAR) Mission which is designed to search for signs of (blank) in the centers of other galaxies, in Feb 2013, NASA announced that NuSTAR had obtained the first ever measurements of the rotation rate of a (blank)

The maria (singular= mare)

any of the lowlands of the moon or mars that resemble a sea when viewed from Earth, named by Galileo who was first to saw moon wasn't a smooth pure surface, most craters are results of impact by meteorites and (blank) formed as heated lava escaped from lunar interior, Man first stepped foot on Sea of Tranquility on Moon, craters remain intact for billions of years on moon, mercury, and places without atmospheres or tectonic activity because there is nothing stopping it, (blank) are much darker in color while highlands are lighter,

Meteoroids

any piece of interplanetary matter that is smaller than an asteroid, 3 diff sizes--> (small micrometeorites which land on Earth's surface constantly, meteors whose trails can be seen from Earth when it heats up through passage into Earth'a atm some are known as fireballs which are very bright and sometimes survive to hit Earth, diff objects as they pass through atm, many small meteoroids are debris from asteroid collisions, unlike most asteroids (blank) may orbit Sun in any direction unlike most asteroids, only 1 in 1 million (blank) that hit the atm survive to reach the surface, many other meteors come from material evaporated from a comet's nucleus

Type .Ia

are thought to be carbon-oxygen rich white dwarfs that have had helium dumped onto them from an orbiting companion helium rich white dwarf, they are called (blank) because they only reach 1/10th the peak brightness of the Type Ia, (blank) are found in regions of recent star formation and also in regions where no star formation has occurred recently, has 1/10 nickel, lasts 1/10th as long, no prominent lines of hydrogen seen in their spectra, were discovered by Caltech,

inversion layers

areas in Earth's atm where temperature temporarily increases with increasing height, two or 3 places in Earth's atm, one such (blank) is the ionosphere where the upper atm is being ionized by solar UV radiation, LA basin has a low altitude (blank) which results in heat waves and traps pollution beneath

granules

areas where hot material in photosphere (light areas) is rising from below and then descending (dark surroundings), (blank) is gas that is heated from below so portions are rising with heat from convection then drop (constant motion)

The Helium Flash

as a red giant evolves and hydrogen burning takes place in outer layers of the star, the helium "ashes" are dumped back onto the degenerate core, raising the temperature of the core, (blank) is the runaway helium fusion reaction that occurs during the evolution of a red giant, in some stars (blank) can consume the star's helium in a matter of seconds, (blank) happens in a matter of minutes, this reaction is called the Triple-Alpha Process bc it takes 3 alphas (helium 4) to create a Carbon 12, when the core temp reaches 100 million Kelvin the helium nuclei combine and form carbon, following the (blank) the star forms four layers 1)an inner degenerate carbon core which can't contract 2)a layer of helium that fuses to carbon in a conventional manner, 3) an outer hydrogen-fusing shell, and 4) an outer layer below 10 million Kelvin in temperature where no fusion can take place & the red giant star then expands further,

Vesta

asteroid with diameter greater than 300 km (but not the largest)

Kirkwood's Gaps

asteroids not evenly distributed across asteroid belt, at certain distances such as 2.5 and 3.28 gaps appear which are related to 1/3 and 1/2 of Jupiter's orbital period, second example of resonance phenomenon bc synchronous tugs from Jupiter on the asteroids which used to be located in the original orbits, also correspond to 2/5 and 3/5 of Jupiter's orbital period

adrian van maanen

astronomer who mistakenly concluded that he could detect the rotation of nebulae which were in fact galaxies, some of (blank)'s erroneous observations are shown (pic), only taught what he did wrong, Arrows are what he thought was proper motion of individual stars but would have had to be traveling faster than speed of light -also,galaxy actually spins in opposite direction

Stellar occultation

astronomers know ahead of time from computing locations of celestial objects so that they can observe it in front of a star (how they discovered rings of uranus), tried to do this with neptune and found ring arcs which we later found out were rings, used to identify Uranus' ring system and Pluto's atm,

liquid metallic hydrogen

at 15,000 km below the clouds, it is theorized that the pressure and temp create a state of (blank), as one goes deeper into Jupiter's atm, the gaseous hydrogen turns into (blank)as one goes deeper into Jupiter's atm, the gaseous hydrogen turns into (blank)

galaxy collisions

because of distances galaxies exhibit no proper motion, evidence of past collisions has to come from present appearance, when galaxies collide gas and dust clouds interact but there are few collisions between stars, sometimes 2 galaxies may merge or sometimes a large galaxy may cannibalize a smaller one, one competing theory suggests that active galaxies are the result of galactic collisions

asthenosphere

below lithosphere composed of about 40 miles of the mantle, lithosphere floats over zone of weakness above asthenosphere and plates can move horizontally from side to side

helioseismology

beneath photosphere can't see into sun, we "image" inside by analyzing rates of solar rotation inside Sun, in (blank) we measure the frequencies of these solar oscillations and compare these measurements with the predictions of our computer models of the sun, we can show that surface differential rotation rate persists throughout the solar convection zone but the solar interior beneath the convection zone appears to rotate more like a solid body rather than differentially, comparisons of predicted and observed oscillations can probe internal structure of sun, during Rhodes' PhD research he found the solar convection zone is much deeper than ppl used to think it was, also discovered it is possible to measure rotation rate of the Sun by comparing frequencies of waves that are traveling in opposite directions around the solar surface and extending this idea we can probe how rapidly the different parts of the solar interior rotate,

Mars

better fit as Earth's twin although it is only half of Earth's diameter, (blank)'s surface is populated with craters, large volcanoes like Olympus Mons, and canyons like Valles Marineris (can't all be seen with just eye but both polar caps of frozen C02 can be --only planet with surface features that can be seen from Earth and is best seen at opposition--> the configuration of a planet when it is opposite the Sun in our sky which is every 2.2 yrs for mars), markings have been observed since 1660 and were used to determine rotation rate, the Mariner spacecraft of late '60s/ 70's returned images that ended speculation about canali, dark markings would change and people thought it was due to changing vegetation patterns (were actually changes in soil and carbon dioxide frost (white))but we could see this because atm isn't opaque, crust is prob too thick for tectonic activity but could have it, polar caps consist of water ice base covered during winter by C02 and when caps shrink the C02 sublimes into martian atm (goes from solid to gas), is most oblate of all terrestrial planets but still very spherical,

asteroid belt

between orbits of Jupiter and Mars, most orbit sun at distances from 2.2- 3.3 AU

plages

bright regions of hotter gas than surrounding photosphere, surround many sunspots, areas of elevated gas temp,

infrared companion

can be evidence of possible planetary bodies, such as seen with star T Tauri

Messier Catalog

catalog made my Messier to keep celestial objects straight, had 110 objects in it,

planets

celestial objects with masses from 0-.0136 solar masses, in an H-R diagram their track will never touch the main sequence

barycenter

center of mass

canali

channels (naturally cut), On Mars, these were confused to be made by advanced race of beings after the public saw Giovanni Schiaparelli's drawing of (blank)

Prominences

channels of solar material above the disk of the sun, viewed from side, looks bright bc density of gas is much higher than density of surrounding corona even though corona is much hotter, may reach heights from a few thousand to even a million km above photosphere, stable (blank) can last for several days while explosive ones can reach speeds of 1,500 km/s, gas that is spewed out when a (blank) erupts is a coronal mass ejection

filaments

channels of solar material, viewed from in front of photosphere (high density) where it looks lighter bc photosphere has higher density than the (blank)

differentiation

chemical separation, the denser materials sank to center of early Earth (which began as entirely molten), explains why Earth is more dense at center

Steven Hawking

claimed that black holes might disappear or evaporate when the particles inside them would meed anti-particles from the outside universe, said angular momentum can be removed from a spinning black hole even though no mass can escape from it, claimed out entire universe might be viewed as one gigantic black hole, theory of everything,

Jupiter

closest Jovian planet to Sun, 318x more massive than Earth, but only 1/4 of mean density--> composed of higher percentage of light elements (hydrogen/helium), 12 years to complete 1 orbit around sun but rotates every 9 hr 50 min--> is very oblate (jovian rotate much faster) but poles rotate a few mins slower than equator --> swirling at boundaries (differential rotation just like other Jovian and Sun), pioneer 10 (1973) and pioneer 11 (1974) flew very close and measured magnetic field and magnetosphere, later in 1979 Voyager 1& 2 flew past and took photos, unlike terrestrial, surface features have little effect on upper atm--> long lasting weather patterns, Great Red Spot-> red oval in atm, Galileo probe tells us Jupiter is about 86% hydrogen, 14% helium, small amounts of water, CH3 and highest clouds have ammonia crystals with varying temps w/ highest clouds hottest and lower clouds colder in gaps, composition is closer to stars than it is Earth but would have to be 80x more massive to support nuclear fusion so it can't act as mini star, some areas in atm at depth of 60-80 km have temps like Earth but pressure is 10x greater--> high pressure makes hydrogen into liquid metal, colors seen in Jupiter's upper atm indicate photochemical reactions induced by sunlight/atm lighting, the light areas (zones) are high pressure regions of rising gas and dark areas (belts) are low pressure regions of falling gas, emits about 2x more energy itself than it receives from sun bc this excess energy is left over from its formation and bc of great size its cooling very slowly and may be contracting, has 4 known rings and largest (galilean) moons in solar system, poles show aurorae

interstellar medium

clouds, nebulae, within a radius of a thousand parsecs from Earth, astronomers estimate that (blank) contributes about 15-30% of the total mass of dust, gas, stars, absorption lines due to interstellar gas tend to be narrower than those produced by a star's atmosphere, lines caused by stellar atmospheres will have a different Doppler shift than those caused by stellar atmosphere gas, light from distant stars is reddened by the dust through which it passes because dust grains scatter blue light more than red but this has nothing to do with the doppler effect, interstellar dust grains are smaller than the wavelength of light, spectral analysis indicates that interstellar dust contains carbon in the form of graphite, gas will generally be much cooler than the gas of the stellar atm, stars form out of (blank), dust in space accounts for 10% of the total mass of (blank), and remaining 90% is in form of interstellar gas,

giant molecular clouds (GMCs)

cold (10k) (blank) are found in the galaxy and this is where stars are born, galaxy contains around 5,000 GMCs but not 5,000 shock waves as of now but could have star formation in them later, avg density of a (blank) is about 2,000 molecules/cm^3, may contain as much as a million solar masses of material, strong UV radiation may evaporate (blank) but particularly dense regions called EGGs are left behind,

coupled partial differential equations

combine Newton's equations of motion w/ knowledge of how gases and radiation interact w/ knowledge of solar equation of state w/ knowledge of nuclear reactions into a set of (blank) which are solved on computers to form computer model of sun,

Comet Hale-Bopp

comet -->spinning (once every 12 hrs) solid thing with material spiraling around off of it because as nucleus spun the material was ejected through geysers and spiraled away, nucleus is about 15 km across and spins once every 12 hours,

gluons

compose the quarks which comprise hadrons

Oort Cloud

composed of billions of comet nuclei, proposed in 1950 by Jan Oort,

baryons

composed of tinier particles known as quarks

lithosphere

comprised by Earth's the outer 40 miles of it's mantle (2200 miles in total) and it's crust (60 miles total), a new way of dividing earth, spherically shaped shell this is broken into 12 tectonic plates, (hard boiled egg analogy) lithosphere floats over zone of weakness above asthenosphere and plates can move horizontally from side to side

conjunction

configuration of a planet which isn't Opposition, occurs when two astronomical objects have either the same right ascension or the same ecliptical longitude, normally when observed from the Earth, at (blank) Mars is about 250 million km further from Earth

head of a comet

consists of coma and nucleus (solid chunk that starts somewhere in universe), the (blank) also sometimes has a hydrogen envelope

Conditions in Solar Interior

consists of free nuclei and free electrons bc high temps strip electrons away from nuclei, this behavior is similar to that of a simple gas,

Callisto

contains Valhalla- largest known impact crater, outermost Galilean moon, shows more cratering, has least active surface, experiences little tidal heating, bright ice & dark dust,

Local Supercluster

contains the Local Group and the Virgo cluster, 60% of members of (blank) are contained in a disklike structure

ratio of 100

corresponds to 5 magnitude difference

present evolutionary theories

current theory: object shrinking under force of gravity heats up, high temps near protosun would have prevented the condensation of more volatile elements & planets forming near the Sun would thus be made mainly of nonvolatile, dense material, farther out the eddies would be larger and temps cooler so that larger planets could form that were composed of volatile elements (light gases) which don't condense bc of high temp of Sun, as young sun heated up it ionized the gas of the inner solar system and it's magnetic field swept through the ions in the inner solar system causing ions to speed up, and this transfer of energy to the ions caused the Sun to slow its rate of rotation (per Newton's 3rd law of Action and Reaction)which is aka magnetic braking,

plutino

currently, pluto is classified as a (blank) and Charon as a moon,

Ejnar Hertzsprung

danish astronomer, worked in early 20th century, looked at apparent magnitudes and spectral classes of stars in diff star clusters (Subaru and Pleiotes (M45) are 2 examples)

belts

dark areas are low pressure regions of falling gas, caused by convection

Sunspots

dark spots on Sun first reported by Chinese in 5th cent BC, regions that are about 1500 degrees cooler than the surrounding photosphere, energy given off by black body (stefan-boltzmann law), temp phenomena lasting a couple hours/ few months, were first observed by Europeans Galileo and Thomas Harriott in 17th cent, (blank) are locations where Sun's magnetic field passes from its interior through the photosphere into its atm, bc of the dynamo effect the magnetic field varies across Sun, magnetic field in a sunspot is up to several thousand Gauss in strength (much stronger than what we're used to, often come in pairs in roughly east west direction, current model has patterns of magnetic field lines within the Sun's interior forming tubes that gradually become twisted from the Sun's differential rotation. Forced to the surface, these magnetic tubes become visible as sunspots--> breaking the surface weakens the field lines and the sunspots eventually all die out, (blank) blocking reduces energy output,as new lines form deep within sun sun's overall magnetic polarity reverses every 11 years and thus one complete magnetic cycle is 22 years long after which the magnetic field will reverse direction, (blank) blocking reduces the energy output,

oceanic trenches

deepest portion of ocean floor, sea floor is burrowing downward,

Chandrasekhar Limit

degenerate electrons can withstand pressures created by up to 1.4 solar masses, beyond that point--known as the Chandrasekhar Limit-- white dwarf stars cannot exist as white dwarfs, main sequence stars with masses up to 4 solar masses can end up as white dwarfs only if they lose mass during the red giant and planetary nebula phases, for otherwise they would exceed the above mass limit, if accretion brings the mass of a white dwarf above the (blank), electron degeneracy can no longer support the star and it collapses, the collapse raises the core temperature and runaway carbon fusion begins, which ultimately leads to an explosion of the star, (blank) is upper mass that a star in white dwarf status can attain, stars within this limit can experience recurrent nova until the other paired star runs out of material to give the white dwarf, it can't have more than 4 x mass of sun and still be degenerate--> gravity won't allow it to exist as a degenerate ball of gas when it exceeds mass limit --> explosion of entire star (Type Ia supernova) which can only happen in close binary systems,

Cepheid variable

dela cephei is 1st discovered (blank) by John Goodricke in 1784, is a variable star (grows in size temp and brightness)--> life on surrounding planets would fry and freeze, our sun will be a variable star, other stars were then seen to show same characteristic light curve of rapid brightening and slower dimming, doppler effect data showed that these stars are pulsating in rhythm with their changes in luminosity, each (blank) has a constant period of about 1 day to 3 months--> allows absolute magnitude to be determined, cepheid variables with similar light curves, doppler effect data showed that these stars are pulsating in rhythm with their changes in luminosity, brighter cepheids have longer periods and this was discovered by Henrietta Swan Leavitt in 1908, (range from 1 day to 3 months), are valuable distance indicators and none are close enough to be measured by parallax but in 1917 Harlow Shapley worked out way to determine distances to Cepheids in our own galaxy, two diff types of Cepheid variables differing from each other in luminosity by about 2 magnitudes for the same period which made it hard to determine the correct relationship between Cepheids' periods and absolute magnitudes accurately, the periods of cepheids are important because the period- easily determined, allows the absolute magnitude to be determined, in 1917 the U.S. astronomer Harlow Shapely worked out a complex statistical method to determine distances to Cepheids in our own galaxy,only about 1,000 (blanks) have been detected,

moonquakes

detected by sensors on Moon, occur when micrometeorites bombard moon or when Moon is at perigee

Masatoshi Koshiba

developed Kamiokande and Superkamiokande neutrino detectors in Japan, shared 2002 Nobel Peace Prize in Physics w/ Ray Davis,

Standard Model of the Big Bang

developed by Robert Wagoner, William Fowler, and Fred Hoyle, in this original "Big Bang" model, the universe began at t=0 in a state of infinitely high temperature and density--> called cosmological singularity, no longer believe singularity can exist,

Robert Wagoner, William Fowler, and Fred Hoyle

developed standard model of the Big Bang

Pluto

diameter is .2 of Earth, furthest "planet" from Sun, discovered by accident (pluto as planet X was too small to cause irregularities in Uranus' orbit like they observed by using the perturbation theory), at perihelion pluto is closer to sun than neptune so its gaining sunlight and getting warmer (got enough heat to create atm by vaporizing methane which will prob turn into liquid/solid at aphelion bc its so cold) which we observe through stellar occultations, most highly inclined orbit tilted 10 more degrees than 2nd largest (mercury=7 degrees pluto=17), very elliptical orbit, very small, rotates retrograde (bc obliquity is > 90 degrees),5 total moons, some think Pluto os a former moon of Neptune that was somehow ejected (Charon-moon discovered by James W. Christy kind of disproves this)--> we don't know how pluto originated,rocky core surrounded by ice, went from planet-> dwarf planet-> plutino , Pluto Express spacecraft will tell us more about Pluto,

Giuseppe Piazzi

discovered Ceres in 1801 (first asteroid), it was discovered at 2.8 AU from the Sun bc of the gap in Titius and Bode's Law

Measuring Galaxies

distance mass and motion are most important elements, Cepheid variables are excellent distance indicators but can be seen in only relatively nearby galaxies out of approx. 20 million ly, Hubble and Humason's discovery of the Hubble Law/ Law of the Redshifts showed that the universe is expanding and this is the work for foundation of cosmology, but the redshifts Humason observed are not due to the Doppler effect, determining a precise value for the Hubble Constant is difficult because accurate measurements of distant galaxies are hard to obtain

Venus

diameter is 95% that of Earths, surface is shrouded by heavy clouds which spreads heat all around planet and less of a day and night temp diff, since 1961 we have been bouncing radar signals off its surface to learn about motions and surface features, (blank) rotates backward, photos of sharp edged rocks confirm that winds at surface are fairly calm, 2/3 of surface is covered by rolling hills, highlands occupy <10% of surface, low-lying areas make up rest, has about 1,000 craters that are larger than a few km in diameter, shows past evidence of volcanic and tectonic activity: mountains large lava flows, volcanoes, indirect evidence of possible recent volcanic and tectonic activity, shows retrograde rotation (bc its the planet that gets closest to Earth when it overtakes us, Venus's orbital period is shorter than Earth's so it overtakes us often and when this happens Earth exerts a tidal pull/backward tug that has made venus rotate backward, Earth can exert this tug because Venus's mass isn't exactly symmetric), crust is too thin for tectonic activity, has much more albedo than Earth and has been called morning and evening star, obliquity is almost 180 degrees--> perfectly downward--> rotates backward which we confirm through RADAR bc we can't detect surface features bc of atm, if Venus's orbit were in the ecliptic then obliquity would be 180 degrees, probably no magnetosphere so solar wind runs straight into ionosphere

Luminosity classes

diff groupings into which stars can be placed based upon differing widths of their spectral lines (Ia, Ib, II, III, IV, V, wd), 90% are in main sequence V, the smearing effect leading to (blank) was discovered by Antonia Maury in 1880s, stars at top of V live for hundred millions years while at bottom of V in H-R diagram they live for hundreds of billions, knowing a star's (blank) and temp gives its absolute magnitude from its location in the H-R diagram, a star's luminosity L can be determined from its absolute magnitude M, its luminosity is also equal to the product of energy emitted per sq cm per second times surface area,

magnetic reconnection heating

different from radioactive decay heating, due to very dynamic changes in magnetic field in photosphere and above of Sun, is somewhat localized but entire corona is hot so could be more than one mechanism

Uranus' Orientation/Motion

differential rotation (like Jupiter & Saturn), equatorial plane is tilted approx 90 degrees to plane of revolution, obliquity is 98 degrees--> North Pole located beneath ecliptic plane (and faces sun but this will flip in 42 years)--> rotates retrograde, orbital period is 84 years,

John Baptiste Riccioli

discovered 1st binary star in 1650 but wasn't recognized as being true binary then, had better quality telescope than galileo,

Edwin Hubble

discovered Andromeda with Cepheid variables, in 1924 he found Cepheids in 3 sprial nebulae proving their existence as spiral galaxies,

Sir William Herschel

discovered Uranus in 1781,first person to estimate direction in which sun is moving in 1783 by measuring the total space velocities of stars in vicinity of Sun,was able to show sun is moving toward Vega- one of the summer triangle stars visible in Summer, in 1802 he obtained first evidence that some double stars orbit one another, in 1781 he counted the # of stars in different parts of the sky and came up with Grindstone model of Milky Way, took up night sky from England and divided it into patches but couldn't see central portion of galaxy which is only visible from Southern hemisphere, did star gauging (star counting), and came up with the Grindstone Model of the Milky Way, insterstellar dust in our Galaxy prevented (blank) and Jacobus Kapteyn from getting accurate star density counts-->thought Earth was at center of galaxy

John Goodricke

discovered eclipsing binary Algol in 1783, discovered first Cepheid variable star in 1784,

E.C. Pickering

discovered first spectroscopic binary in 1889

Saturn's Ring system

discovered in 1655 by Christian Huygens, Galileo did NOT bc his telescope wasn't strong enough (he thought Saturn had a very flattened disk), Cassini later discovered gaps in between 2 groups of rings, bc obliquity is similar to Earth's if we are in a certain position we can't see them bc they're so thin and don't reflect light from said positioning, there is a gap between two ring, very thin rings, made of small particles of water ice or rock coated with ice (not sheets), ring particles follow Kepler's laws of planetary motion (rings on inside orbit faster), over 1000 separate rings, the origin: major impact theory (moonlet orbits closely to saturn and then is slammed into by passing asteroid and it breaks apart), OR moon/comet gets too close and is pulled apart by saturn's tidal force on it, or material was too close to surface of saturn to ever form into moon in first place (Roche limit= minimum radius at which a satellite may orbit without being broken up by tidal forces), largest division between some of the rings is Cassini's division--> caused by gravity of Mimas acting synchronously on orbital path of nearby ring particles, small shepherd moons explain presence of other ring features

Ceres

discovered in 1801 by Giuseppe Piazzi, largest asteroid w/ 30% of all mass of asteroids--> dwarf planet, was discovered bc of gap in Titius and Bode's Law there

seasons on Mars

each Martian season is almost 6 months long,More extreme season changes in Mars and Earth in Southern hemisphere

neutrino

each of 3 families of leptons (electron muon and tau) has an associated (blank) which means little neutral one, elementary particle that was previously thought to have no rest mass and no charge but which is now thought to possess mass and which carries energy from a nuclear reaction, can change types during their trip through the solar interior and to Earth, Wolfgang Pauli originally thought they were massless,

one magnitude difference

equals a ratio of 2.512 in amount of light received, but this is premodern magnitude scale

perchlorates

evidence of (blank ) on mars mean that soil could possibly support growth of plants if an oxygen-rich atmosphere could be created

Samuel H. Schwabe

existence of Great Red Spot on Jupiter, amateur astronomer, 1851 announced discovery of sunspot cycle which lasts about 11 years but ranges 7 to 17 years, diff cycles have diff lengths and diff mins and maxs

general theory of relativity

expands special relativity to include accelerated systems and it presents an alternative way of explaining the phenomenon of gravitation

Galactic Cosmic Rays

extremely high-energy particles, mostly protons, high speed nuclei which originate outside our solar system, continually produce radioisotopes that are captured in living organisms and ice, solar wind shields Earth from (blank) but when Sun is in a low state and the wind is reduced or absent, the rate of production of the radioisotopes is enhancced

Mar's atmosphere

extremely thin atm which can't retain its infrared radiation and results in -220 F nighttime temps,though mars is colder than Earth its lower escape velocity and lack of ozone layer has allowed water vapor methane and ammonia to escape, water vapor is broken up by UV and the hydrogen escaped and oxygen reacted with iron-rich crust to form rust--> Mar's red color, surface pressure is about 1/200 of Earth's, this planet has the thinnest atm of all terrestrial planets, Mars has less mass/ gravity/escape speed than Earth maybe bc Jupiter prevented Mars from grabbing enough material, low escape speed allows atm to dissipate into space, water in Mar's atm could have frozen in soil,escape velocity is 5km/s (less than half of Earth's)

Saturn's magnetic field

field is only 5% as strong as jupiter bc it has less charged particles (liquid metallic hydrogen layer is thinner than same layer at Jupiter)--> less strong electric current, less strong magnetic field and magnetosphere (other particles are not in ring plane but are trapped in magnetosphere)

Joseph Taylor and Russell Hulse

first discovered binary pulsar in 1974

Father Angelo Secchi

first introduced spectral classifications in 1863 put spectral lines in wrong order bc he didn't know reason for diff in appearance of spectra

double planet theory

first suggested in 1800s saying earth and moon formed at same time from same rotating disk of material

mariner 10

flew past Venus and Mercury, American space probe that flew by Mercury in 1974, brought back photographs, confirmed Mercury has no permanent atm bc escape velocity is too low, detected a weak magnetic field, thin temp atm (like Earth's moon)

stellar wind

flow of nuclear particles from a star, reason the giant planets of outer solar system would have collected outflowing gases bc (blank) of early sun would have swept inner solar system of these volatile elements,

Post-Inflationary Quark Soup

following the end of the Inflationary Epoch the quarks and anti-quarks combined into the heavier particles that we call hadrons, the hadrons comprise the baryrons, anti-baryrons, mesons, and anti-mesons that we observe today, the weak nuclear force and the electromagnetic force separated during this epoch, when the universe was 10^-4 sec old, the energy density had decreased to the point where the photons that were filling the spacetime had too little energy to create additional baryron/anti-baryron pairs, the pairs which had been created previously continued to run into/annihilate each other but resulting photons had too little energy to create additional particle pairs, additional photons of energy were created at the expense of the annihilated pairs, at 10^-2 seconds the temperature had dropped to 10^11 Kelvin, by a little more than one second after the Big Bang the particles had moved far enough apart as the universe expanded that the weak nuclear force could no longer make the existing neutrinos and antineutrinos interact with the other particles--> dark drifting neutrinos may be our dark matter,

Hubble Law/ Law of the Redshifts

formed by Hubble and Humason, v=H0d, v=radial velocity, d=distance, H0= Hubble Constant, it is used to measure distances to distant galaxies,is what tells us the universe is expanding, when light from distant galaxies is redshifted it loses energy, but the redshifts Humason observed aren't due to the doppler effect, an expanding universe had to have a beginning, and as we look outward we are looking back in time, however we cannot see back to the beginning, we can only look back until we run into the opaque fog of the early universe for which we cannot penetrate, for most distant galaxies the (blank) must be used to determine their distances,

albedo

fraction of incident radiation that an object reflects, reflectivity

Edmund Halley

friend of Newton,used Newton's methods & own observations to calculate orbits of a number of comets, correctly surmised that these prior comets were the same comet and predicted return of next comet (Comet Halley), was first to recognize effect of other bodies on comets' orbits, in 1718 (blank) discovered that stars move with respect to one another,

Percival Lowell

from famous family, had observatory in Flagstaff AZ in 1894 who reportedly saw many canals and oasis with vegetation but couldn't be confirmed by others, in 1905 he initiated search for Planet x (pluto) but died before it was found by Clyde Tombaugh in 1930

Type I supernovae

gas that is hydrogen has already disappeared from star so there are no hydrogen line spectra

coronal mass ejection

gas that is spewed out when a prominence erupts, halo coronal mass ejections flow towards earth and are seen as circular around sun,

standard solar model

generally accepted theory of solar energy production, predicts that billions of neutrinos per second flow from the Sun, neutrinos react very little with ordinary matter so detecting them is difficult, original US based neutrino detector only counted 1/3 predicted number so this is a problem, there are 3 diff types of neutrino but only one is detectable through US detector,

radioisotopes

generated by Galactic Cosmic Rays and are captured by organisms and ice, 14C, 18O and 10Be, when sun is in a low state and the wind is reduced/ absent the rate of production of (blank) is enhanced,

habitable zone and Venus/Earth Differences

goldilocks zone, temperature is just right for life, shifts in distance depending on type of star, Venus's higher surface temp due to being closer to Sun created a run-away greenhouse effect where water didn't condense out of its atm into oceans that could absorb C02 (like Earth's oceans) bc most C02 remained trapped in Venus's atm and trapped much of Venus's own infrared heat --> thick clouds and high temps which baked more C02 out of surface rocks,

stellar nursery

group of forming stars where we look for solar systems forming

Jovian planets

group of outer planets far from sun, are mostly liquid and gas, have bigger diameters and larger masses than terrestrial planets but lower density, rotate quickly, have more natural satellites than terrestrial planets, 4 (blank) have 159 satellites, each have a ring system, bigger diameters and larger masses, all (blank) rotate faster than do any of terrestrial, planets but pluto rotates more like terrestrial, dense atm, all 4 gas giants radiate more energy as blackbodies w/ infrared than they receive from sun,

terrestrial planets

group of small inner planets near sun, have more density than Jovian planets, are mostly solid, have low mass, rotate slowly, 4 (blank) have 3 total satellites, no ring systems, thin atm (except for Venus), are massive enough for their gravity to have formed them into nearly perfect spheres

solar active regions

groupings of sunspots and their plages

electron degeneracy

happens in cores of red giants, electrons are so compacted they can't touch any further, high mass gets electrons to touch one another, Chandrasekhar was an expert in (blank), degenerate electrons can withstand pressures createdd by up to 1.4 solar masses, beyond that point-known as Chandrasekhar limit- white dwarf stars cannot exist as white dwarfs,

new moon

happens when moon is directly in front of sun and the illuminated side of the moon is facing away from the Earth, the sun is far enough away from the moon that it illuminates 1 hemisphere at a time, sun moon and earth are at syzygy (also happens at full moon)

Mercury

hardest planet for people on Earth to see (bc its so close to sun in sky)--> can be seen on low horizon during sunrise/sunset, exhibits phases like venus, (blank) is similar to our Moon (both are covered in impact craters but (blank)'s are less prominent because it has more gravity, also why ray patterns are less extensive on (blank), (blank) lacks the larger maria seen on Moon b/c it cooled more slowly so lava was able to flow out and fill old holes, (blank) has more scarps (long cliffs) and most are believed to have formed from the shrinking of Mercury's crust as it cooled, surface rocks look similar to Earth's --> (blank) must have relatively large iron core, astronomers suspect a large asteroid blasted away most of (blanks) rocky mantle, high temps on (blank) can reach 842 degrees F, on night-sid temps can fall to -250 degrees F, high albedo for (blank)'s polar regions suggests presence of ice on floors of craters that have never seen any sunlight, its field is very weak which could be because it rotates so slowly and could have a molten interior but it still has a small magnetosphere, in 2011 NASA sent Messenger spacecraft into orbit around Mercury--> observed ice in floor of craters around mercury's poles, size is less than 1/2 of Earth's diameter, bull's eye impact crater Caloris Basin, small magnetic field detected by Mariner 10 which suggests that part of its metallic core must be molten in order for dynamo effect to operate but in spite of large core the field is weak prob because of slow rotation rate

glueballs

has been speculated that some matter may exist which is entirely comprised of gluons--> (blank)

Jacobus Kapteyn

he and Herschel made star gauging counts which were mistaken in figuring out there distances because of interstellar dust---> thought earth was at center of galaxy (geocentric), in 1930 interstellar dust was discovered, resolving the conflict between the discoveries of Shapely, Oort, and Lindblad and the star counts of Herschel and (blank), Kapteyn cottage in Mt. Wilson

Principle of equivalence

holds that the effects of the force of gravity are indistinguishable from those of acceleration

spectral classes

hottest to coolest: OBAFGKM(RNS), O stars range in temp from 30,000 K to 60,000 K, M stars have temps less than 3,500 K, within each spectral classes they're divided into 10 subcategories (0- hottest through 9-coldest), sun is G2, Sirius is an A star, in letter order it goes hot to cooler left to right (ionized to molecule), with increasing temp ionization and excitation increases and peak wavelength shifts smaller and smaller, the stronger the absorption line the deeper the depression in the graph bc more light is absorbed

volcanic activity

interval of extensive (blank) caused by radioactive decay 900 million years ago which resulted in the origin of Earth's atmosphere through process of outgassing, heat generates (blank)

Hydrostatic Equilibrium

hydro: gas, hydrostatic: stationary fluid/gas that isn't flowing, equilibrium: balance, forces are getting balanced, the structure of a star changes when there is an imbalance of gas pressure which points outward and gravity brings particles of star together, when balance is in equilibrium the star is in (blank) which is why we exist today (our sun is in this), (blank) is the balance between pressure caused by weight of material above and upward pressure exerted by material below, we don't think sun is shrinking or growing, the pressure at the Sun's center is 1.3x 10^9 times that at the surface of the Earth, think of structure of star as blowing up a balloon,the sun is in (blank) but over long periods of time it is expanding, cooling and becoming more luminous,

spiral arms

hydrogen gas clouds detected by 21 cm radiation are located at the same place as newly forming stars, applying the principle of the Doppler shift, astronomers use the 21 cm radiation to provide further evidence for the spiral nature of the Galaxy, some recent evidence suggests that the Milky Way Galaxy may actually be what is known as a barred spiral galaxy, Individual stars move into and out of (blank), during 18 galactic orbits the stars have been changing (blank),

Deuterium

hydrogen nucleus that contains one neutron and one proton

Stellar Thermostat

hydrostatic equilibrium in a star acts as a (blank) so that nuclear fusion proceeds at a uniform rate, is a way of monitoring its own evolution,

conservation of angular momentum

ice-skater analogy,in whirlpool evolutionary theory modified by Laplace-> the rotating contracting disk of gas should speed up according to the law of (blank) and the sun-the center of the former rotating cloud- should be rotating much faster than it is observed to be,

planetesimals

idea that eddies condense to form particles that would grow over time to become (blank) which in turn would sweep up smaller particles through collision and gravitational attraction, proposed by Carl von Weizsacker in 1940s, over millions of years remaining (blank) fell onto moons and planets causing cratering we see today,

Jupiter's magnetic field

if core exists it is very small (1% of planet), field is strong nearly 20,000 times stronger than Earths, it is generated by the large mass of liquid metallic hydrogen (bc of high pressure) and its rapid rotation rate, a lot of flowing electrons to generate magnetic field,magnetic field deflects solar wind around planet and traps charged particles of the wind in belts,

local celestial meridian

imaginary great circle that runs north to south, passing through both north celestial pole and observer's zenith

Thomas Wright

in 1751 (blank) in his Theory of the Universe said that the Sun is in a disk-shaped system of stars, like a circular flat pill,

Immanuel Kant

in 1755 introduced the notion of what he called "Island Universes" (galaxies) was 1st to propose other galaxies existed, updated Descarte's whirlpool theory,

Felix Savary

in 1827 (blank) showed that the stars in a binary orbit each other in elliptical orbits,

Michelson-Morley Experiment

in 1887 showed convincingly that the speed of light cannot depend upon the motion of the observer (which was the Earth in that case), the experiment was conducted by the American physicists Albert A. Michelson (of speed of light fame) and Edward W. Morley in Cleveland, Ohio at what is now Case Western Reserve University, light was supposed to travel through Ether-- set up table to have light beam travel at direction Earth is spinning at right angles (trying to find different speed of light regardless of fact that table was spinning) --> convinced there is no Ether, Einstein used the result of this experiment as the basis for his Theory of Special Relativity published in 1905

Henrietta Swan Leavitt

in 1908 discovered that for Cepheids the brighter variables have longer periods, bc we can measure periods more easily bc of her we can determine absolute magnitude more easily

Shapley-Curtis Debate

in 1920 there was a famous debate in Washington D.C. between Harlow Shapely and Heber D. Curtis, an astronomer form the Lick Observatory which is located east of San Jose, Shapely argues that the Milky-Way was large enough to contain all of the known stars and nebulae, curtis argued that the Milky Way was not this large and that there were in face other galaxies in the universe, Shapely is said by some historians to have argued more persuasively, but we now know that he was wrong, in late 1924 Hubble found Cepheid variables in three spiral nebulae, proving that they were actually spiral galaxies, the proof that galaxies existed outside the Milky Way expanded the scope of the universe, Hubble resolved the controversy, because he demonstrated that the Milky Way Galaxy is not the only Galaxy in the universe, Hubble has been considered the equiv. of Copernicus, shapley won debate but lost war,

Ralph Alpher and Robert Herman

in 1940s the Americans (blank) were first to suggest that radiation existed, they predicted that the photons from the fireball should be seen at the Earth as radio waves having a temp only a few degrees above absolute zero,

Robert Wilson and Arno Penzias

in 1965 (blank) of the Bell labs accidentally discovered cosmic microwave background radiation while they were doing applied research on microwave transmission, their antenna picked up the low-intensity radio waves characteristic of the background radiation which they first thought was some kind of noise (as observed by COBE) , they mentioned this to Bernard Burke who realized what they had found, (blank) were awarded the 1978 Nobel prize in physics for this discovery,

Jocelyn Bell

in 1967 British graduate student (blank) discovered an unknown source of rapidly pulsating radio waves while using a student built radio telescope to discover quazars, subsequent discoveries of similar sources gave rise to the name pulsar, after (blank) made her accidental discovery the first suggested explanation for the regular pulses was the "little green men" hypothesis, the idea was suggested and then rejected by (blanks) thesis advisor, Anthony Hewish of Cambridge,

COBE (Cosmic Background Explorer)

in 1989 (blank) satellite successfully measured the background radiation at various wavelengths, all its measurements showed agreement with a black body at 2.726 K, (blank) data matched the theory to within .03% which is 100 x better than the best data before (blank), data even allow us to measure the direction of our Galaxy's motion relative to the so-called Hubble FLow of expansion, in 1992 when discovery of tiny amplitude temp fluctuations in Cosmic Microwave Background Radiation was announced in the press, the writers referred to this as the Holy Grail discovery of cosmology--> proved that large-scale spatial structure was already in existence at 379,000 years after Big Bang, in 2006 2 leaders of (blank) missions George Smoot and George Mather shared in the Nobel Prize

Solar Dynamics Observatory (SDO)

in 2002 NASA announced selection of 3 instruments for next large solar mission the (blank), one of the instruments is a follow-on to the MDI which obtains high pixel images every 45 seconds called the Helioseismic magnetic imager, earth orbiting satellite, launched in early 2010, once or 2x a year we end up in an eclipse season where satellites orbiting earth can't see sun,

Hoba meteorite

in Namibia, weighs 65 tons and is largest of its kind ever to be found

Source of Sun's Energy

in mid 1800s Helmholtz and Kelvin proposed that a slow gravitational contraction was the source of the Sun's energy but such a mechanism would power the Sun for only a few tens of millions of years at the current solar luminosity, Einstein explained this through E=MC^2, now believe fusion reactions of turning hydrogen into helium inside core is source of energy, in a series of nuclear reactions which occur within the core of the sun 4 hydrogen nuclei are fused to form 1 helium nucleus (proton-proton chain) and in the process energy in the form of gamma rays is given off, these reactions inside the Sun convert only .7% of original mass of four hydrogen nuclei into energy, to produce Sun's energy output nearly 5 million tons of matter must be converted into energy each second so 610 billion kg of hydrogen be transformed into 606 billion kg of helium,

Robert Dicke

in the 1960s (blank) a Princeton physicist made plans to search for the radiation

controversy over the nebulae

in the early part of the 20th century there was considerable disagreement about the possible existence of external galaxies,

Helioseismic Magnetic Imager

instrument on SDO which obtains 4096 x 4096 pixel solar images every 45 seconds for NASA, Rhodes's is a co-investigator on this instrument, allows both helioseismic and solar magnetic studies,

reflection nebula

interstellar dust that is visible due to reflected light from a nearby star, such (blank) are blueish in color due to the reflected light, dust clouds can contain up to 1 million molecules per cm ^3,

emission nebula

interstellar gas that flouresces (when electrons drop down from levels and gas emits photons--most of the time the lower energy state for hydrogen atom has antiparallel spins (like Venus/Uranus/Pluto) due to UV light from a star near or within the nebula, a cloud is called a (blank) if it is dense enough or bright enough to show up in a photograph, the pink color of a (blank) signifies recombining hydrogen that had been ionized by O and B stars, (blank) also known as bright line nebula,

interstellar clouds

interstellar medium, can contain less than 1,000 molecules per cubic centimeter, span huge volumes of space from parsecs to tens of parsecs across, a (blank) is called a nebula if it is dense or bright enough to show up in a photograph

infrared radiation

interstellar medium, cirrus emits (blank) because it is warmed slightly by light it absorbs,

Ice Ages

intervals of extremely cool temperatures, records show that spacings of past ice ages have periodicities of 41,000 and 100,000 years as they would have if Milankovich Effect is real

Absolute Magnitude

intrinsic luminosity of a star, is defined as apparent magnitude a star would have if it were at a distance of 10 parsecs, sirius's absolute magnitude is +1.45, (blank) of sun is +5 , today we infer distances through (blank), 3 related things are apparent magnitude (as observed from telescope on Earth) and (blank), and distance--> knowing any 2 of these can compute the 3rd , a negative (blank) corresponds to a brighter star, in the H-R diagram the Sun will often be luminosity of 1 in solar units,

H II

ionized hydrogen (glowing red in color) like chromosphere of sun which emits H alpha

composite spectrum binary

is a binary star system with stars having spectra that differ enough to distinguish them from one another, used to be called a double/multiple line spectroscopic binary where you get spectra of both stars shifting simultaneously even though you can only see one star

quasars (quasi-stellar source or QSS)

is a class of abnormal galaxy, a (blank) is a small intense celestial source of radiation with a very large redshift, are bluish-white objects and emit X-Rays, the sun and most stars aren't strong radio sources; hence the QSS or quasi-stellar, in 1960 an unusual starlike object--3C 273-- was discovered that emitted intense radio waves, this and other similar objects were named (blank), the unusual spectral lines found in 3C 273 and 3C 48 were shown by Schmidt in 1963 to be highly redshifted hydrogen lines, since the early 1960s about 7000 (blank) have been discovered, unlike 3C 273 and 3C 48, most quasars are not sources of radio waves, many (blank) vary in intensity in an irregular way, changing intensity in weeks or months, this observation confirms their small size, redshifts for (blank) range from .16 for 3C 273 up to 4.73 for one of the farthest known (blank), the latter is receding at about 94% the speed of light, the two most distant (blank) are calculated to be 11 and 18 billion ly away, but universe is 13.7 billion years so no quasar could be seen that is 18 (blank) ly away from us bc light hasn't reached earth yet, at such great distances (blank) must be more luminous than an entire galaxy but are much smaller, (blank) may be associated with the nuclei of some types of galaxies , (blank) are found at the greatest distances bc they are the brightest of the active nuclei objects and bc they may indeed be older and thus farther away than other active nuclei,

Local Group

is a cluster of 28 or so galaxies that includes Milky Way, most galaxies are part of clusters which is a gravitationally linked assemblage

spiral galaxies

is a disk-shaped galaxy with arms in a spiral pattern, Hubble divided (blank) into normal (blank/S) and barred-(blank/SB), each type of (blank) is then divided into (Sa)- largest nuclear bulges and most tightly wound arms, (Sb)- middle sized bulges and moderately wound arms, (Sc) have smallest bulges and loosely wound spiral arms, (S0) appear to have disks like spirals but have no spiral arms at all, the spiral nature of our galaxy was first hinted at by the distribution of O- and B-type stars, Confirmation came from radio telescope observations of 21 cm radiation, most (blank) are from 50,000 to 200,000 ly across and contain from 10^9 to 10^12 stars, contain both old (Pop II) and young (Pop I) stars, they contain both gas and dust and have star formation going on,

Valhalla

largest known impact crater in solar system, on Jupiter's moon Callisto,

electron

is a lepton and isn't thought to be composed of smaller particles, one of 3 families of lepton with muon and tau, has associated neutrino and anti-particle

irregular galaxy

is a normal galaxy of irregular shape that cannot be classified as spiral or elliptical, fewer than 20% of all galaxies fall in the (blank) category and are all small w/ fewer than 25% of number of stars in Milky Way, collisions between galaxies are not unusual because on average galaxies are separated by distances only about 20x their diameter, some (blank) are seen to be pairs of galaxies in collision

barred-spiral galaxy

is a spiral galaxy in which the spiral arms come from the ends of a straight bar running through the nucleus rather than from the nucleus itself, SB, normal spirals have no bar, (SB0)- have a bar and disk but no apparent spiral arms, (SBa)- have bars, large bulges, and tightly wound-spiral arms, (SBb)- have bars, medium sized bulges and moderately wound spiral-arms, (SBc) have bars, small bulges, and loosely-wound spiral arms, individual stars move into and out of spiral arms

radio galaxy

is a type of abnormal galaxy having greatest luminosity at radio wavelengths, Cygnus A was 1st radio galaxy was discovered in 1951 and has a double-lobed radio source associated with the visible light image, the two radio lobes are found on opposite sides of the optical counterpart galaxy, these 2 lobes give off synchrotron radiation, as in the case of pulsars, this type of radiation comes from electrons traveling near the speed of light which then spiral around the lines of the magnetic field, so this tells us that radio galaxies have two large regions of energetic particles and large-scale magnetic fields, (blank) often exhibit unusual jets in visible light

the universe

is about 13.7 billion years old,

Uranus' magnetic field

is comparable to Saturn's magnetic field, could be convection going on inside uranus and neptune causing convection of charged particles causing (blank), something has to explain this bc there is no liquid metallic hydrogen, the magnetic field axis is tilted 55 degrees with respect to its rotation axis (largest planetary angle between two axis)

cold dark matter

is matter that is too cool to emit sufficient radiation to allow us to detect it, may be contained in galactic halos,

Total Solar Irradiance

is measured to predict global climate properties but is generally too small to alter them, there is a strong correlation between solar cycle length and sea surface temperature

giant star

is one of great luminosity and large size

21 cm radiation

is radiation from atomic neutral hydrogen with a wavelength of 21.1 centimeters, in nature both electron and neutron are spinning, lower energy (common) state is antiparallel-- collision of photons can flip electron, 21 cm radiation is absorbed by electrons spins and they are flipped but will spontaneously flip back to antiparallel (low to high- absorption) (de-excitation high energy-low emits photon), this phenomenon doesn't describe an electron move from one sized orbit to a different sized orbit but just deals with the parallel or anti-parallel aspect

cocoon nebula

is the dust and gas that surrounds a protostar and blocks much of its radiation, evidence for protostars is obtained from the infrared radiation from the (blank)

particle density

is the number of separate atomic and or nuclear particles per unit of volume

Doppler Effect

is the observed change in wavelength from a source moving toward or away from the observer, when the source is moving toward the observer, one hears/sees a higher frequency (shorter wavelength) wave-- this is called blue shift, the opposite is red shift, named for Austrian physicist Christian Doppler, he explained this effect in 1842, ex.: change in pitch (frequency of sound) when either source or listener moves, other doppler effect measurements: 1. Speeds of cars measured by police radar. 2. The rotation rate of the Sun. 3. The rotation rates of the planets and the rings of Saturn. 4. The motion of some binary stars. 5. The motions of stars within our Galaxy., 6. The motions of pairs of galaxies. The finite speed of travel of light and sound is why we have the doppler effect, doppler effect works for all EM waves (radio/ microwave/ ultraviolet etc), spectral lines in stellar spectra make (blank) powerful bc measuring amount of shift of stellar spectral lines can determine the radial velocity of the star relative to speed of Earth, lines caused by stellar atmospheres will have a different Doppler shift than those caused by stellar atmosphere gas,

the Schwarzschild radius

is the radius of a sphere (the event horizon) around a black hole from within which no light can escape, as long as the radius of a collapsing star is greater than the Schwarzschild radius the star is not considered to be a black hole, but once the radius is equal to the (blank) it is said to remain a black hole even when its radius shrinks to become smaller than the size of the event horizon, Rs (km)= 3M (M=solar mass), the size of the (blank) depends only upon the mass of the star,

lunar temporary atmosphere

is very low density, surface gravity is too low for the moon to have a substantial atm, any early atm would have long since evaporated into space, (blank) is formed when solar winds knock off small numbers of sodium atoms from lunar surface, w/out permanent atm the temperatures range from -170 degrees celsius to 130 degrees

Martian Canal Controversy

italian word canali was mistranslated by English speakers to mean the straight human made canals (not natural canali), thought water was being carried from polar caps to equatorial region by intelligently made canals,

Spectroscopic Parallax

knowing a star's absolute magnitude (H-R diagram) and its apparent magnitude (with telescope) allows us to compute its distance, the distances to stars too far away for parallax measurements can be determined using this procedure,

asteroids

known as minor planets, Ceres (discovered in 1801 by Giuseppi Piazzi) is largest asteroid and takes up 30% of all mass of all asteroids, approx 10,000 other have been discovered, astronomers originally thought asteroids were due to exploded planet but there is no known mechanism for making a planet to explode, the large gravitational attraction of Jupiter doesn't allow these asteroids to become a diff planet (Titius and Bode's Law), the mass of all asteroids wouldn't equal mass of planet anyway,

Pangea

land mass, all of current continents were combined about 250 million yrs ago into single supercontinent, has since split apart

Viking Probes (I and II)

landed on Mars in 1976, confirmed that Mars has dry riverbeds (similar to arroyos of the U.S. desert southwest) gave 1st surface pics, time delays of (blank) which orbit mars have been carefully measured and appear to best match the predictions of Einstein's theory on General Relativity

Great Red Spot

large red oval, in atm of Jupiter, 3 people given credit for seeing a spot on Jupiter in 1664 and 1665, but it is not known for certain that they saw the same spot we observe today bc Cassini didn't record color, is 40,000 km long and 15,000 km across, very large storm center, could fit 3 earths inside, high pressured storm system that rotates counterclockwise with a period of 6 days, spot has lasted for a very long time, 1831: Schwabe notes same spot we see today

solar supergranulation

larger pattern of convective motion, are 20 to 30 x larger than the granules and are regions of horizontal (reminds us of plate tectonics) gas flow, this was discovered at Mt. Wilson in 1960s,

Grand Unification Epoch

lasted only from 10^-43 to 10^-35 second, during which all matter and energy were interchangeable and in equilibrium and the remaining three of the four natural forces were combined into one force, during (blank) quarks and leptons and their corresponding anti-particles were constantly colliding with each other and in those collisions energy was liberated, during (blank) two photons of energy could collide with each other and generate a particle-anti-particle pair if their total energies exceeded Mc^2, where M is their combined rest mass, matter, anti-matter, and photons were all thought to be in equal amounts at that time, universe also cooled during this time,

Subrahmanyan Chandrasekhar

leading theorist in the study of white dwarf stars was an Indian-American astrophysicist who shared the 1983 Nobel Prize in physics with William Fowler of Caltech, worked in electron degeneracy

phase transitions

liberated energy, separated 4 natural forces (the strong nuclear force, the electromagnetic force, the weak nuclear force, and the gravitational force), one of these (blank) caused the early universe to inflate very rapidly for a very brief moment of time in the past

solar transition zone

lies directly above chromosphere, is only about 200 km thick, temp ranges from about 25,000 K at base to 600,000 K, (blank) and corona have recently been studied with NASA's Trace spacecraft, can't see (blank),

zones

light areas are high pressure regions of rising gas, caused by convection

flyweight stars

lightest weight stars, stars with a mass of less than (40%) .4 solar masses but more than .08, , convection occurs throughout most or all of the volume of the star, hydrogen from throughout the star is cycled through the core, the entire star runs on low hydrogen at the same time, will take 100 billion years to completely burn its hydrogen, will become white dwarfs through gravitational shrinkage, the hypothetical lifetime of a (blank) is more than 6 times the assumed age of the universe-> not enough time for a (blank) to become a white dwarf so the low-mass white dwarfs that are currently observed must have originated in a different manner, for a (blank) to end main sequence life it uses up all of the hydrogen fuel supply through out the interior bc it is fully convective but for the Sun it will still have unfused hydrogen, none of (blank) have had time for burning up entire supply of hydrogen because this takes 100 billion years and when this happens they become white dwarfs without going through a red giant phase and giving off a planetary nebula,

magnitude system

logarithmic, faintest stars- 6th magnitude, 1st magnitude

scarps

long cliffs in a line, on Mercury, these are believed to have been formed from the shrinking of Mercury's crust as it cooled

Epoch

longer period of time than era

Saturn's Atmosphere

low surface gravity, features similar to Jupiter's but Saturns winds are faster, radiates more heat than asorbed from sun (porb because of contraction like other gas giants)

M-Class stars

may remain protostars for hundreds of millions of years, T Tauri stars are thought to have enormous flares which play a part in blowing away the cocoon of (blank) as well as K type stars,

mountains on the Moon

lunar highlands, (blank) are the result of excessive cratering over eons on the Moon NOT from tectonic activity there, highlands are lighter in color,

Pallas

major asteroid with diameter > 300 km

neutrons

massive nuclear particles with no electric charge in nucleus

dynamo effect

mathmatical model that explains the Earth's and other planets' magnetic fields as being due to electric currents flowing within molten iron cores, part of Mercury's metallic core must be molten in order for the dynamo effect to operate but recent measurements of heat loss indicate its core is not molten

Positive Cosmological Constant

means by which Einstein adjusted his theory to insure universe neither collapsed or expanded, was of + value--> there is an as yet undetected repulsive force which is causing objects in the universe to accelerate their expansion, this force has generally not been expected to exist but some think they have found indirect evidence proving (blank)'s existence, (blank) was introduced before Hubble announced his evidence for the expansion of the universe--> Einstein heard Hubble Law and thought (blank) was biggest mistake of his life but he may have been right because new idea is that repulsive force comes from the curvature of spacetime, (blank) was in connection with the static model of the universe when Einstein proposed it as being the explanation for why the universe hadn't fallen in on itself, the 1998 magazine cover of the cartoon of einstein showed him smiling bc Einstein died in 50s and was dead by then, artist made the picture because Einstein may have been correct when he thought (blank) was positive

apparent magnitude

measure of amount of light received from a celestial object, a star that is located far from Earth will look fainter than will an identical star nearby bc of inverse-sq. law of light , Sirius's (blank) is -1.47 due to its closeness (2.7 pc) from Earth,Andromeda and Magellan clouds are two visible galaxies from Earth,

Heating mechanism

mechanism which heats chromosphere and corona of Sun but isn't full understood, was thought to be fueled by shock waves,and thought to be fueled by magnetic reconnection heating

Astrometric Method

method of observing the wobbles in the motions of stars for detecting extra-solar planets

Roche limit

minimum radius at which a satellite (held together by gravitational forces) may orbit wthout being broken apart by tidal forces, no big moons have ever been found in Roche limit, saturn's rings are inside Saturn's Roche limit so no moons can form from the particles, all ring particles would form a small moon about the mass of Janus, also pertains to the lobe around novae which becomes peanut shaped bc of the gravitational pull of its companion and rotation of the nova, if a star overflows the Roche lobe the gas flows across the lagrangian point onto the companion star,

escape velocity

minimum velocity an object must have to escape the gravitational attraction of an object such as a planet, Earth's (blank) is 11 km/s, Moon's (blank) is 2.5 km/s, what we look at to see if a planet has retained an atm, if a planet's escape speed is at least 5 to 6 times the avg speed of molecules at that planet's atm temp, the planet will retain an atm for +5billion years,

Meteor crater

misnomer, should be meteorite crater, created a 1 mi crater in desert, prob weighed about 300 million tons

The Big Bang

model for (blank) was first proposed by Georges Lemaitre, what came "before" the origin of the material universe which we now observe? maybe our current universe was created as a fluctuation within a previously-existing one,

5 magnitude difference

modern magnitude scale where (blank) equals ratio of 100 in light received, so a difference of (blank) corresponds to (2.512)^5= factor of 100 in light received at the telescope, the magnitude system is logarithmic, modern measuring allows astronomers to determine magnitudes to an accuracy of .001 or better, some stars are so bright (Sirius) that they have negative magnitudes,

outer core

molten, composed of liquid metals and is about 1800 km in thickness approx. 1100 miles), most predominant (liquid) metals are iron and nickel

Clusters of galaxies

most galaxies are part of (blank), is a gravitationally linked assemblage, in clusters where galaxies are packed close together, ellipticals dominate --supporting notion of frequent mergers, in loosely packed (blank), ellipticals are fairly rare,

The orbits of Asteroids

most orbit sun in Asteroid belt between Mars and Jupiter, asteroids aren't evenly distributed across asteroid belt, at certain distances gaps appear which are related to 1/3 and 1/2 of Jupiter's orbital period --> Kirkwood's Gaps due to synchronous tugs from Jupiter on asteroids , example of resonance, revolve around sun in counterclockwise direction like planets, most orbit in or near plane of ecliptic

spicules

narrow jets of gas which are part of chromosphere but extend through transition zone into corona, last about 10 to 20 mins each before they disappear and are replaced by new (blank) due to some sort of magnetic squeezing

triple-alpha process

need 100 million K degrees in red giant instead of 10 to have enough kinetic energy to slam together the 3 helium nuclei to form a carbon by overcoming natural electrostatic repulsion, (blank) occurs during the Helium Flash which can consume the star's helium in a matter of seconds,

H I

neutral hydrogen (transparent)

scattered disk

new claim of a 3rd source of comets with a mid-range

protosun

newly formed sun from egg, it took around 30 million years for (blank) to reach the main sequence

Opaque Era

not much happened, we went from hot to cold, temp dropped to 3000 K (temp of cold stars)--> (blank) soup becomes transparent (fog lifts and you can begin to see around you) *this didn't happen overnight*--> first neutral atoms were created during (blank), between 100 seconds and 379,000 years after the Big Bang the remaining free photons and the helium, deuterium, and lithium nuclei moved about in an opaque sea of photons, electrons, nuclei, and neutrinos, at t=180 the temp had dropped to about one billion Kelvin (point C in the diagram), by 370,000 years the temperature had dropped to 3000 K (about the surface temp of cool stars, or Point D), once the temp had dropped to 3000 K, the Opaque Soup began to clear and became transparent (much as what happens when a fog lifts and you can begin to see around yourself), during (blank) many of the nuclei which had been created captured free electrons and the first neutral atoms were created, many of these neutral atoms were then ionized by the photons of energy which were still present in large numbers, by the end of (blank) these photons lost so much energy in the expansion that they could no longer destroy those neutral atoms which had been re-created when previously-freed electrons re-combined with positively-charged nuclei,some people claim to have made observations of the (blank) portion of the universe

Mercury's atmosphere

not permanent because (as in case of Moon) solar wind knocks some atoms off of this planet but they form a thin, temporary atmosphere, high temps on mercury can reach 842 degrees while on night side they can reach -250 F

strong nuclear force

nuclear reactions involve forces between nuclear particles, one of (blank) and one of weak nuclear force

weak nuclear force

nuclear reactions involve forces between nuclear particles, one of said forces

brown dwarf

object that isn't massive enough to be called a star but are too massive to be planets, thermonuclear fusion reactions characterize stars, but brown dwarfs aren't stars because they don't have this occur bc they don't have enough internal pressure, failed/ wannabe stars , planets can orbit these, (blank) is a starlike object whose mass is too small to sustain nuclear fusion, probable limits of mass are from .0136 to .08 solar masses, objects with less than .0136 solar masses are planets, while objects having more than .08 solar masses are main sequence stars, a (blank) was not seen first until 1994, a (blank) is not a star because it cannot sustain nuclear reactions in its core (not enough high temp in core to start up reactions) , (blank) operate in niche in mass, in an H-R diagram their track will never touch the main sequence

cosmic microwave background radiation

observed by COBE spacecraft in early 1990, large (spatially) and small scale tiny (in amplitude) temperature fluctuations,

Solar Flares

occur mostly during sunspot maxima, explosive outbursts near sun's surface, according to sunspot model (blank) occur when a great number of twisted tubes of magnetic field lines release their energy at once through photosphere, light from a flare will reach the Earth 8 1/3 minutes after flare has occured, (blank) blast out large numbers of very energetic charged particles that will take about 3 days to reach Earth since the particles don't travel at speed of light, large (blank) cause spectacular aurorae and can affect earthly radio transmissions if ionosphere is disrupted by high-energy particles,

Alan Guth

of MIT, proposed the inflationary model in early 1980s

Ray Davis

of U Penn, 11 years ago developed initial solar neutrino detector in Homestake Mine in South Dakota, shared 2002 nobel peace prize in physics with koshiba

open/ galactic star cluster

once a star system has about 10 or more members it is called (blank), we negate the differences between the stars within the (blank) when discussing their distances from Earth, all the stars in a single cluster have roughly a common birthday but will evolve at diff rates bc they have diff masses (more massive protostar the more rapidly it will evolve), can see through it

parallax angle

one half of the max angle through which a star appears to be displaced in 6 months due to Earth's motion around Sun, parallax angle of nearest star besides sun is only about .76 seconds of arc and others of other stars are smaller than this angle distance to star (ly)= 3.26 ly/ parallax angle in arcsec distance to star (pc)=1/ parallax angle in arcsec, (blank) is inversely related to distance

tau

one of 3 families of leptons with electron and muon, has associated neutrino and anti-particle

muon

one of 3 families of leptons with electron and tau, has associated neutrino and anti-particle

Europa

one of Jupiter's Galilean moons, surface is ice, moderate density indicates a rocky world covered by ocean of frozen and possibly liquid water, experiences tidal heating from tidal force from Jupiter on it's eccentric orbit which squeezes and heats it, is now the subject of interest of life in its ocean, fault lines on ice indicate shifting below (liquid water is below)

Io

one of Jupiter's Galilean moons, surrounded by halo of sodium atoms, gas around it comes out of volcanoes which were discovered by Linda Morabito, Jupiter's tidal forces have squeezed and heated Io causing formation of erupting volcanic geysers causing halo of sulfer and sodium, is composed mostly of rock,

Titan

one of Saturn's major moons, 2nd largest moon in solar system besides Ganymede (Jupiter) has an atmosphere which is composed mostly of nitrogen and a trace of methane and argon (when sun strikes methane it can create some components for life) (we know of the methane bc of absorption lines), titan has a solid surface and liquid lakes of cool sluggish hydrocarbon, one of 7 largest planetary moons, Cassini mission sent Huygens Probe to Titan's atm in 2005 which returned images of Titan and showed lake of liquid hydrocarbons, atm is denser than Earth's bc low surface temp of -220C is enough to keep gas molecules (nitrogen and methane) from escaping, atm is thought of as colder version of Earth's early atm,

Charon

one of pluto's moons discovered by James W. Christy, orbit is tilted to 61 degrees to Pluto's orbit around Sun, orbits Pluto every 6.4 days (same as Pluto's rotation),

basalt

one of the Moon's minerals

leptons

one of two major classes of particles which is now thought to be most fundamental of particles instead of proton and neutron, other is hadron, electrons and neutrinos are (blank) and neither are thought to be composed of smaller particles, 3 families of leptons: electron, muon, and tau which are each known to have own anti-particles, each of 3 families of leptons has associated neutrino (little neutral one), lightweight,

hadrons

one of two major classes of particles which is now thought to be most fundamental of particles instead of proton and neutron, other is lepton, composed of tinier particles known as quarks, heavyweight,

partial solar eclipse

only a portion of the Sun's disk is covered by the Moon's disk

Wolfgang Pauli

originally believed solar neutrinos were massless,

white dwarfs

our Sun will become a (blank) after becoming a red giant, planets can orbit these, are hot but dim stars bc they're small, may be .01 sun's size, are about same size as Earth, Sirius B has about the same mass as Sirius A, but B is small and hard to see because it is a (blank), astronomers estimate that 10% of all stars are (blank), (blank) are the cores of red giants that remain after the outer parts of the original stars have blown away, lighter (blank) are composed of helium and carbon, (blank) formed from more massive stars may contain nuclei of oxygen, neon, sodium, and even iron, (blank) have observed surface temps between 4000 K and 85000 K, their masses range from perhaps .02 solar masses and up to 1.4 solar masses, a typical (blank) will have a .8 solar masses & a diameter of 10,000 km (3/4 of Earth's) & a density of 10^6 g/cm^3, a teaspoon of (blank) material would weigh two tons, to get to the (blank) stage, a star will have gone through these stages: protostar, main sequence star, red giant, planetary nebula, the leading theorist in the study of (blank) was an Indian-American astrophysicist named Subrahmanyan Chandrasekhar, he shared the 1983 Nobel Prize in physics with William Fowler of Caltech, (blank) are like standard candles, a (blank) has nearly the mass of the sun in the volume of earth (high density), (blank) originate from flyweight stars and gravity OR red giants shrinking

red giant

our Sun will evolve and become a (blank) after using up all the hydrogen in its core where its size will reach past the orbit of earth , is one of great luminosity and large size, a (blank) can have a lower surface temp (less radiation per square meter) but a higher luminosity because its diameter will have expanded 200 times or more, the core of a (blank) consists of helium nuclei intermingled with electrons (similar to a regular gas), the core of a (blank) will not continue to contract indefinetly bc of electron degeneracy (degenerate: cannot shrink further bc electrons are touching each other and can't be pulled any closer with gravity alone), temp of degenerate gas doesn't depend on pressure, the moment our future sun's core becomes degenerate we will have a helium flash when the temp and fusion rate will go up very quickly like an explosive fusion reaction bc we try to start fusing helium into hydrogen but degenerate core won't let us do so without minor explosion, (blank) are on the red cool side of the H-R diagram and will have a cooler surface temp bc of highly expanded diameter, the (blank) will have innermost core of degenerate carbon-> helium shell fusing to carbon-> hydrogen shell fusing to helium, and all but core is expanding, a horizontal move on the (blank) is a constant luminosity change while right to left is heating up,

convection zone

outermost portion of solar interior in which energy that was originally liberated in the core is transferred to the solar surface by process of convection, covers about outermost 28% of solar radius,

radioactive decay

period of 900 million years where Earth was heated by (blank) of uranium and other elements, this source of heat resulted in an interval of extensive volcanic activity, elements on periodic chart are naturally radioactive and will spontaneously fission: the process by which atomic power plants generate power, particles come out of nuclei carrying kinetic energy which is dissipated in the form of heat, wherever we have large amounts of these radioactive elements in the crust and mantle the earth will be heated, (blank) resulted in formation of volcanic activity which then formed Earth's atm through outgassing

solar minimum

period of very few sunspots on sun's surface, last (blank) was in 2008-2009 and was much longer than normal minima,

convection

phenomena which moves plates in which warm magma rises, moves horizontally, and falls back inward at subduction zones, hat happens when you heat something from below and it rises, is responsible for sea floor spreading and continental drift,

meteor shower

phenomenon of a large group of meteors seeming to come from a particular are of the celestial sphere but earth is actually passing through a swarm of small meteoroids at such a time, most major (blank) are associated with comets, some showers change intensity from year to year bc the swarm of particles that cause the shower clump together in one region of the comet's orbit

meteor

phenomenon of a streak in the sky which results when a dust-grain sized or pebble sized meteoroid is heated up by its passage through Earth's atm, the heated material heats up the atm until a trail of glowing material can be seen from the ground, some are very bright and are called fireballs, a typical (blank) begins to glow at a height of 80 miles and burns out at about 50 miles, can be seen only if its within 90-160 miles of the viewer--> 25 million meteors visible on Earth a day, 1,000 tons of meteoritic material hit Earth every day

field planets

planets that don't orbit stars but are in star zones, they escaped from stars they orbited

Hertzsprung-Russell diagram (H-R)

plot where one of things plotted is absolute magnitude (or luminosity) versus surface temp (or spectral class) for most stars , approx 90% of all stars fall into band running diagonally across the diagram called main sequence stars on (blank) fall into categories such as main sequence, white dwarf, red giant, and supergiant, census plot of 2 properties of stars (intrinsic brightness plus surface temp), knowing a star's luminosity class and temp gives its absolute magnitude (M) from its location in the H-R diagram, the sized of a few very large stars have been measured directly by knowing the temp of a star gives its energy emitted per square meter E=(theta)(T^4), since we also know the star's luminosity (from it's absolute magnitude) we can calculate the surface area of the star (L=(sigma)(T^4)(4piR^2), from the surface area the radius of the star can be determined, (blank) started theories of star birth in early 20th century, top left is hot and bright, top right is cool and bright, bottom left is hot and faint, bottom right is cool and fait, (hot-> cool) (faint^ bright)

Mass-Luminosity Diagram

plots mass versus luminosity of a number of stars, more massive stars are more luminous, the (blank) relationship holds only for main sequence stars because things don't change so dramatically, (blank) relationship is valuable in investigating less accessible stars and in constructing and evaluating hypothesis on life cycle of stars, the most massive stars are more luminous, if there is an enormous range of intrinsic brightness then we use the log of mass vs. the log of luminosity to fit it all on one plot --> results in straight line, plots low mass main sequence to high mass main sequence,

zenith

point directly overhead every location on Earth

ammonia

poisonous substance found in trace amounts on Jupiter, the highest clouds are composed of (blank) crystals and have a temo if 150 degrees, have a pressure at the top of the clouds of 70% the pressure found at Earth's surface

radiative zone

portion of solar interior immediately outside solar core, is portion of solar interior where gamma ray photons from core travel outward by process of radiative diffusion,

positron

positively charged electron emitted from the nucleus in some nuclear reactions

magnetic braking

present evolutionary theory explanation of sun's slow rotation rate stating as protosun heated up it ionized the gas of the inner solar system, the sun's magnetic field (which the interplanetary lines were of spirals) then swept through the ions there causing them to speed up. Newton's 3rd law shows this transfer of energy to the ions caused the Sun to slow its rate of rotation,(blank) happens to pulsars as well

radiative diffusion

process where gamma ray photons from core travel outward to radiative zone

shock waves

produced in solar interior and which dump their energy in corona, a mechanism we thought heated sun

inflationary universe model/ inflationary epoch

proposed by Alan Guth in 1980s, is a modification of the standard big bang model that holds that the early universe experienced a brief period of extremely rapid expansion, as the universe expanded during the Grand Unification Epoch it also cooled, after 10^-35 seconds the temperature had dropped to 10^27 Kelvin and the universe underwent a "phase transition" in which the strong nuclear force split off from the electromagnetic and weak nuclear forces known as symmetry breaking, the energy density of the scalar field would have added to the rate of expansion of the early universe, the (blank) holds that an "inflation" of the universe took place so quickly that any portion of it that had great curvature before the universe inflated became flat as a result of the inflation, at first, the (blank) theory had difficulty explaining how galaxies and clusters of galaxies could form relatively soon after the big bang out of a completely uniform universe (but they aren't uniform bc cold dark matter generated gravity waves which led to formation of galaxies in walls and bubble-type configurations and cold dark matter would have added to the curvature of spacetime and would have prevented the background radiation from being uniformly distributed

Kelvin-Helmholtz theory

proposed in 1800s that slow gravitational contraction fueled sun but was abandoned bc it didn't account for age of sun which they didn't know til 20th century geologists proved it

Einstein

proposed in 1905 that mass and energy were interchangeable and even claimed all matter and energy are equivalent in most famous equation E=MC^2 where M=rest mass of particle C=speed of light E is equivalent of energy, in reactions that fuel stars the mass of nucleus is lost and converted into energy, 1905 was his special year where he also proposed theory of special relativity-> any object in motion relative to an observer at a velocity close to the speed of light at constant velocity will appear larger than it does at rest

large impact theory

proposed in 1970s, Moon formed as the result of a glancing impact between a large Mars-sized object and the Earth, explains the relative compositions of Earth and Moon, Moon's orbit, and rotation rate of Earth, has been successfully modeled on super computer,

capture theory

proposed in early 20th century, says Moon was originally solar system debris that was captured by Earth's gravitational field, but a 3rd object is required for capture and chances of this happening are slim

Von Helmholtz and Kelvin

proposed that a slow gravitational contraction was the source of the Sun's energy, was abandoned in early 20th century when geologists showed showed the Earth was billions of years old-- a period 100x longer than the gravitational contraction theory could produce energy

fission hypothesis

proposed that the large basin of Pacific Ocean is place from which Moon was ejected, but (blank) cannot explain the moon's current orbit and doesn't offer rationale for why this would have occured, Pacific ocean basin hasn't always been a basin because of plate tectonics anyway

Hubble Diagram

radial velocity vs. distance, theoretical stars off as straight line then depending what model of the universe we're in it begins to curve, best way to look for evidence about expansion of universe is to compare the recession of speeds of distant galaxies (which are seen as they were far back in time) to the speeds of nearby galaxies, a theoretical (blank) for the expanding models offers choice of closed, flat, open, and steady state universe (All of Friedmann models are < Hubble Time tsub0), these are all families of different models which differ on the amount of particles in the universe, sometimes apparent magnitude replaces distance along the x-axis of the (blank) and sometimes redshift replaces radial velocity on the y-axis, sometimes the axis are reversed as well, the (blank) has fallen out of favor due to lack of data points,

brightness

refers to apparent brightness of a planet/ star/ galaxy

Anthony Hewish

rejected Jocelyn Bell's theory of pulsars and later he and his colleague Martin Ryle shared in the Nobel Prize in Physics for saying that pulsars are rapidly rotating neutron stars

aurorae

result from disturbances in the Earth's magnetic field which cause some of the particles to follow the magnetic field lines down into the atmosphere where their collisions with atoms cause the air to glow in patterns of different colors, two kinds: aurora borealis (Northern hemisphere) and aurora austrialis (Southern hemisphere), form when charged particles from solar field (solar wind) are released from Van Allen belts and slam into upper atm of Earth causing it to glow in colors, large solar flares cause (blank),

Comet Halley

retrograde comet orbit, return was predicted by Edmund Halley with Newton's laws and his own observations, has period of approx 76 years but it varies bc comet is slightly affected by gravity of planets, coma is billions of times less dense than the atm of theEarth at sea level,

Neptune's Magnetic Field

rotates more rapidly than its atmosphere (it rotates with a period of 16 h 3 min=neptune's basic rotation rate),

subduction zone

running into area where moving and denser sea floor plates dips beneath Earth after running into less dense continental plates and eventually slips underneath, this phenomena is called subduction, things come together here (unlike rift zone at the top where things break apart), when things spread and push together they create friction-> heat-> volcanic action in the rift zone, chains of volcanoes are found to lie above the subduction zones as with the Cascade Range in the Western U.S., plates are thought to be moved by convection where warm magma rises-> moves horizontally-> falls back inward at (blank)

Hipparchos

satellite which measured positions and parallaxes to an accuracy of .002 arcsecond, measured distances with an accuracy of 10% for more than 20,000 stars,

sea-floor spreading

sea-floors are spreading away from rift zones, where the warm magma that is rising within the mantle reaches Earth's surface and must stop flowing vertically and move horizontally, this horizontally motion of ocean floors =(blank) &causes Africa and South America to separate (have been for 150 million yrs) and the oldest sea floor rocks are near both continents

proton-proton chain

series of nuclear reactions that begins with 4 protons and ends with a helium nucleus, fuels the Sun,

abnormal galaxies

several classes of (blank), Hubble identified some abnormals as what he called peculiar galaxies, these galaxies have (blank) shapes which suggest that either explosions have occured in them or that they are the result of a collision between 2 otherwise normal galaxies, other classes of (blank) include radio galaxies, Seyfert, N, and quasars

William Fowler

shared 1983 Nobel Peace Prize in physics with Subrahmanyan Chandrasekhar, thermonuclear fusion astrophysicist

quarks

six flavors (up, down, strange, charmed, top, bottom) and 3 diff colors of each flavor--> total of 18 (blank) (baskin robbins caltech analogy)

Gaspra

small asteroid which was imaged by Galileo spacecraft in 1990, has reddish tint and is bright while others are dark like coal

Solar constant

solar energy strikes Earth at a rate of 1,380 watts/m^2, isn't actually a constant bc solar activity varies at each cycle, too much variation wouldn't be good for us on earth, sun emits energy in all portions of electromagnetic spectrum

solar core

solar innermost portion, Sun's (blank) must hold relatively more helium than the surface, Hydrogen--> helium in core of sun due to nuclear fusion bc of heat in core of sun acts as catalyst, region where temp exceeds 10 million K, region where nuclear reactions are taking place, it takes about 1 million yrs for the gamma ray photons emitted in the core to work their way to the solar surface,

nucleus

solid chunk of a comet located in the head that starts somewhere in universe, is buried in coma

Evaporating Gaseous Globules

sometimes become stars as their material sometimes collapses due to gravity, a region that is denser than the rest of the cloud, these form inside GMCs, (blank) warmed and pulled together by gravity but gets dimmer bc surface area is less-> temp increases enough for fusion to begin -> gamma ray photons created by fusion reactions liberate pressure & balance out gravity's inward tug, the protostars go into hydrostatic equilibrium when they're no longer collapsing and become main sequence

red shift

source of sound/light that moves away from the observer, one hears (or sees) a lower frequency (i.e., longer wavelength) wave.

Solar Neutrino Problem

standard solar model is generally accepted theory of solar energy production, predicts that billions of neutrinos per second flow from the Sun, neutrinos react very little with ordinary matter so detecting them is difficult, original US based neutrino detector only counted 1/3 predicted number so this is a problem, currently accepted explanation for deficit of solar neutrinos is that they aren't massless as was originally believed by Wolfgang Pauli, neutrinos possess mass and can therefore change types during their trip through the solar interior and to Earth,

stellar colors and temperatures

star's color is determined by its atmospheric/ surface temp of photosphere, by looking at spectral lines (absorption spectrum- OBAFGKM[RNS] (Oh Be A Fine Girl Kissed Me) hot to cool/ionized to molecule) we can figure out temp of stellar atm bc of the degree of excitation and ionization in star's atm depends solely on temp of that gas, What we measure when we look at stars we're looking at their photosphere, looking for color is looking for temp, ionized species in hot stars (like Sun/ Sirius) with primarily ionized things and hardly no molecules, temperature is most important thing to determine differences in star's atm but density is second, for example we can use a blue and visual vanpass filter on a research telescope to estimate stellar atm temp, as temp increases in blackbodies the one peak wavelength moves toward ultraviolet end of spectrum, the apparent brightness of a star in each band pass tells us which blackbody curve that star represents, the color index is different in magnitudes between b and v, knowing the (blank) of a star gives its energy emitted per square meter (E=sigmaT^4), since we also know the star's luminosity from its abs magnitude we can calculate the surface area of the star and from there the radius of the star can be determined

cosmological singularity

state at time t=0 where the universe began at infinitely high temperature and density, no longer believe such a singularity can exist,

star birth

stars are born in the cold (10k) giant molecular clouds (GMCs) found in the galaxy, the mechanism that begins the collapse of part of a GMC is not well understood, a group of theories holds that the collapse is triggered by a shock wave in the interstellar medium, shock waves could be produced by stellar winds from massive stars, supernova explosions, or from the rotation of galactic arms, for triggering the collapse--> the more material you have the more gravity wants to pull it together

Population III

stars are thought to be very 1st stars that formed just as our galaxy was forming, some claim there is at least one generation of stars younger than the SUn, (blank) are the oldest stars

Star grouping by mass

stars can be grouped by mass as planets (0-.0136), brown dwarfs (.0136-.08) flyweights (.08-.4...lightest), lightweights (.4-2...Sun is 1), super lightweights (2-4 solar masses), middleweights (4-12 solar masses, and heavyweights (12-120 solar masses)

Population I

stars contain heavier elements in their atms, they're very young, some claim there is at least one generation of stars younger than the Sun which is a (blank) star bc both it and Earth contain heavier elements than do the Population II stars, spirals contain both (blank) and Population II stars

Population II

stars contain very little material in their atms other than hydrogen and helium, they're old stars, are older than population I, elliptical galaxies contain primarily old (blank) stars, spiral galaxies contain both (blank) and population I stars

stellar nuclear fusion

stars of low mass like the Sun (<1.5 solar masses) use the proton-proton chain to generate energy, stars of mass greater than 1.5 solar masses have higher core temps that allow a different chain of nuclear reactions to predominate, this series of reactions involves hydrogen, carbon, nitrogen, and oxygen,(blank) is very sensitive to temperature so higher temp makes reactions happen quicker--> sun becomes more luminous and outer portion expands and surface cools,

Principle of Relativity

states that all observers moving at constant velocity relative to each other are equivalent, all such observers will find the same physical laws of motion and none of them can perform any experiment which will allow him to detect his own state of relative motion, there is no absolute frame of reference

water vapor

steam, the first most important gas to be outgassed, went into early atmosphere where it was eventually condensed into liquid form and rained down to become the oceans

Pluto's atmosphere

stellar occultations indicate (blank) is a methane atm, at aphelion it is prob too cold for methane to remain gaseous, (blank) limits an accurate determination of its size,

plate tectonics

study of motions of the Earth's plates across the underlying mantle, causing continental drift, mountains to be uplifted, ocean trenches to be formed, and earthquakes to occur,

symmetry breaking

such a phase transition releases enormous amounts of energy,

Type Ia Supernova

such an exploding white dwarf is called (blank), if accretion brings the mass of a white dwarf above the Chandrasekhar limit, electron degeneracy can no longer support the star and it collapses, the collapse raises the core temperature and runaway carbon fusion begins, which ultimately leads to an explosion of the star, is a subclass of Type I supernova, (blank) are thought to result from the rapid accretion of matter onto the surface of a white dwarf star from a neighboring companion star, (blank) are found in regions of recent star formation and also in regions where no star formation has occurred recently, (blank) reaches maximum brightness in a few days, fades quickly for about a month, and dissipates after a year, models indicate that the energy of a (blank) following the explosion comes from radioactive decay of nuclei produced in the explosion, (blank) will never occur to sun bc there is no close companion, Expansion of universe is not decelerating but has been accelerating for some time—info came from study of 2 diff groups of (blank)- shared in nobel prize in physics, no prominent lines of hydrogen seen in their spectra,

Dust disks

such as discovered around B Pictoris provide evidence that conditions for planet formation exist around many Sun-Like stars

Zeeman effect

sun's magnetic field can be measured indirectly through Zeeman effect which was first realized in 1880s, The remote sensing of (blank) is what makes it so important, George Ellery Hale used the (blank) at Mt. Wilson in 1908 to 1st detect magnetic fields of sun,

Solar Magnetic Field

sunspots are locations where the (blank) passes from its interior through the photosphere into its atm, (blank) can be measured using the Zeeman effect-- splitting of spectral lines by a strong (blank), when magnetic fields are strong enough they deflect the fluid flow, George Ellery Hale in 1908 was US astronomer who 1st detected (blank) and he used Zeeman effect at 60 ft solar tower at Mt. Wilson, the dynamo effect is where motions of charged particles creates planetary fields and (blank), the (blank) in a sunspot is up to several thousand Gauss in strength which is much stronger than that of surrounding photosphere, the current solar sunspot model has patterns of (blank) lines within sun's interior forming tubes which become twisted from differential rotation --> forced to surface--> magnetic tubes become visible as sunspots but breaking surface weakens (blank) field lines and sunspots eventually all die out, coriolis effect, in seconds the sun produces Flares and Coronal Mass ejections, in days the sun rotates and magnetic patterns shift gradually, in months/years the solar dynamo operates to produce the 11-year cycle, in decades the strength of the cycle evolves in ways that are poorly understood,

Sun-Weather Connection

supported by Maunder Minimum and Little Ice Age, terrestrial climate has undergone substantial changes within a few years (involving ocean circulation) and is not yet fully understood but a decline of solar activity over periods longer than the Maunder and Spörer minima provide substantial perturbation to the climate system

1 second after Big Bang

temperature drops to about 10 billion Kelvin (point A on diagram)

10 seconds after Big Bang

temperature is about 2 billion K, the positrons and electrons were annihilating one another (point B in diagram)

Little Ice Age

temps dropped on Earth around 1600/1700s, includes time period of Maunder Minimum --> leads us to believe that changes in solar activity may be able to cause changes in Earth's climate,

event horizon

the (blank) is the surface of the sphere around a black hole from which nothing can escape, its radius is the Schwarzschild radius,

lighthouse model

the (blank) is the theory that explains pulsar behavior as being due to a spinning neutron star whose beam of radiation is only seen as it sweeps by the Earth,

cosmological principle

the basic assumption of cosmology which held that on a large scale the universe is the same everywhere, we now believe this only for the largest physical scale of superclusters of galaxies

Inflationary Epoch

the brief phase during which the universe expanded exponentially, this phase transition included strong nuclear force being separated from EM and weak nuclear force--releasing huge amounts of energy, was added as a modification of the standard big bang model, at the end of (blank) the rapid inflation of the universe ceased and the scalar field oscillated around the minimum value of its energy density, between 10^-35 and 10^-32 after the big bang the universe suddenly expanded at an extremely fast rate, growing by a factor of 10^50 during that time, once the (blank) occurred these large-scale fluctuations became responsible for the perturbations in density in the early universe which would later become the superclusters and clusters of galaxies which we observe today, two parts of the universe that were originally within each other's horizons were outside those horizons, they were still at the same temperature, however, as a result of their condition before inflation--> why all parts of the today's observable universe show a uniform background radiation, it isn't random that the universe looks like this soap bubble cluster--> superclusters--> clusters

Earth's inner core

the centermost portion of this planet it ranges in density up to 13 g/cm^3 and is mainly composed of solid iron and nickel

The phases of the Moon

the changing appearance of the Moon during its cycle caused by the relative positions of the Earth, Moon, and Sun, they follow a sequence of: new, waxing crescent, first quarter, waxing gibbous, full Moon, waning gibbous, third (last) quarter, waning crescent, new, moon exhibits spin-orbit coupling bc tidal effect of Earth on Moon slowed moon's rotational angular momentum so it keeps one face toward Earth constantly, one orbital period for the Moon=one sidereal revolution (27.33 days), Anaxagoras figured out Moon was closer to Earth than Sun & that the side away from Earth would always be dark bc Moon isn't luminous & described Moon's phases, 2 full moons in 1 month= second is a blue moon,

opposition

the configuration of a planet when it is opposite the sun in our sky, can see Mars' features best at this time,

stellar maturity

the cooling of the star's outer layers occurs because as a gas expands, it cools, stars start their main sequence lives on the left side of the main sequence, then move up and to the right as they age, massive stars can use up the hydrogen in their cores in a few million years, the least massive stars can sustain hydrogen fusion for hundreds of billions of years, stars of low mass like the Sun (<1.5 solar masses) use the proton-proton chain to generate energy where hydrogen acts as a catalyst, stars of mass > 1.5 solar masses have higher core temps that allow a diff chain of nuclear reactions to predominate which involve hydrogen, carbon, nitrogen,and oxygen,the CNO cycle is a series of nuclear reactions that results in the fusion of hydrogen into helium where carbon acts as a catalyst in the cycle,

Planck Density

the density of matter can never exceed a limiting value known as the Planck Density of 10^94 gm/cm^3,

parsec (pc)

the distance that a star would have if it had a parallax angle of exactly one arcsecond, no star is located 1 (blank) away from Earth, is a unit of distance, equals 3.26 lightyears, equals 206,265 AU, only stars within 120 (blank) have parallax angles great enough to allow accurate calculations of their distances,

interstellar extinction

the effect by which starlight is absorbed completely by interstellar material,

synchroton radiation

the extremely narrow beam of radio-frequency radiation is caused by a process called (blank) in which electrons traveling near the speed of light spiral around the pulsar's intense magnetic field lines

The Galaxy's History

the galaxy began as a tremendous cloud of gas and dust bigger than the present galactic halo, mutual gravitation between the cloud's parts pulled it together, the center portion was the first to become dense enough for stars to form, dense pockets in orbit around the center became globular clusters, the initial cloud had some rotation and as it contracted it spun faster, the rotating matter formed into a disk, density waves formed in the Galaxy's disk creating the spiral arms where star formation continues today,

Milky Way Galaxy

the galaxy of which the Sun is a part, From Earth, it appears as a band of light around the sky, between 200 and 400 billion stars make up the (blank) most stars in the Galaxy are arranged in a wheel-shaped disk that circles around a bulging center,the diameter of the Galaxy is about 30,000 parsecs, the Sun and solar system is a little more than halfway out from the galactic center, Insterstellar dust in our Galaxy prevented Herschel and Jacobus Kapteyn from getting accurate star density counts from their visual observations, this inaccurate data led them to the mistaken conclusion that the Earth is at the center of the Galaxy, Shapely moved the solar system away from the center of the universe, contains 1) the disk (containing the SUn) 2) the nuclear bulge 3)the nucleus 4) the halo 5) galactic corona, has 200-400 billion stars, Sun's orbital period is 250,000,000 years, there wasn't proof of other galaxies until the 1950s, we used to think we were in spiral arm, now think we're in barred spiral arm, galaxy is rotating differentially (Kepler's 3rd law) outer edge moves slower, center of (blank) lies in direction of sagittarius,

tail

the gas and/or dust that is swept away from a comet's head, straight tail always moves directly away from sun, either made from gas or ions, some are dusty enough that they also have a curved dust tail (it is curved bc particles are being forced away from comet (by solar radiation pressure) in diff ways), (blank) always points away from Sun (doesn't always follow head), after passing the Sun a comet's tail actually leads the head, solar wind flows away from the sun and pushes tail in diff direction (way in the tail is behind head, way out the tail is pushed in front of head by solar wind),at perihelion (warmest part of orbit), the tail swings and begins to decay

continental drift

the gradual motion of the continents in relation to one another, first introduced by Alfred Wegener in 1910

troposphere

the lowest level of Earth's atmosphere which has 75% of its total mass, is about 11 km/7 mi in thickness and is the layer in which our weather occurs , receives most of its heat as infrared radiation from the ground the temp of the troposphere drops with increasing height above the surface, the radiation emitted by Earth can be trapped in Earth's atm by C02 and atm concentration of c02 has risen dramatically past 60 years, such concentration of greenhouse gases could increase global temps

rest mass

the minimum mass of an object Einstein called (blank), any moving object will appear to have a mass greater than its (blank)

corona

the outer atmosphere of the Sun, only visible during a total solar eclipse

evolutionary track

the path on the H-R diagram taken by a star as both its luminosity and surface temperature change with time, it has nothing to do with a star's actual motion across the sky, the most massive stars collapse to the main sequence more quickly bc they evolve quicker, cooler and less massive stars last longer, the curved dash on pre-main sequence (blank) H-R diagram is where fusion begins, the red line is 0 age main sequence (the stars are moving down/left towards this line), the black curves are the pre-main sequence (blank) tracks of protostars of diff masses w/ massive end at top left/bright portion, and low massive end is the bottom right dim portion, the post main sequence evolutionary track of a super lightweight star (3 solar masses) will not contain the helium flash downward dip, down to left motion is pre main sequence, down to right is main sequence, up to right is post main sequence,

geodesic

the path which is the shortest possible option for light to take between 2 points in spacetime, if the (blank) is curved, then the path of light is curved, Einstein proposed in his General Relativity theory that what is called gravity is really the result of curved spacetime, according to general relativity the stronger the gravity the more spacetime is warped around a massive object,

Cosmic Microwave Background Radiation

the photons of energy which had lost enough energy that they could no longer ionize the existing neutral atoms were still filling the spacetime of the early universe, these photons continued to lose energy as the universe continued to expand, these photons are what are seen today as coming from a cold black body of less than 3 kelvin, this cold temp is due to the expansion of the universe, the redshifted photons from an apparently cold black body (but one which was once very hot as we have just seen) are the best evidence that we have today that the Big Bang actually occurred, these photons comprise (blank),

penumbra

the portion of a shadow that receives direct light from only part of the light source, if you're in the penumbra you can see a portion of the light source illuminated

umbra

the portion of a shadow that receives no direct light from the light source, surrounded by penumbra, can't see any of light source illuminated

Fission

the process by which atomic power plants generate power, particles come out of nuclei carrying kinetic energy which is dissipated in the form of heat, wherever we have large amounts of these radioactive elements in the crust and mantle the earth will be heated

nucleogenesis

the process by which the nuclei of heavy atoms are created inside the cores of Type II supernovae is called (blank), (blank) is the formation of nuclei (most of elements in periodic chart in supernovae), hydrogen and helium are the most abundant elements,

fluorescense

the process of absorbing radiation of one frequency and re-emitting it at a lower frequency, UV radiation from the central hot star which expels the nebula causes the material in the shell of planetary nebulas to (blank), Fraunhauffer lines come from electrons changing orbits, Electron doesn't like to stay in higher energy state of the H atom, when it goes from higher to lower it gives off a beam of light Smaller frequency = smaller energy of photon

The Crab Pulsar and Others

the pulsar in the Crab Nebula has a period of .033 second (blinks 30x a second), (blank) emits radiation in all parts of the spectrum, from radio to X rays, its energy output is more than 25,000 times that of the Sun, the lighthouse model of neutron stars/ pulsars: the (blank) is slowing down because of the "drag" of the electrons propelled out into the nebula surrounding the pulsar, the (blank) spins so rapidly because it formed so recently, over time it will lose rotational energy, slow down, and emit less energy, more than 440 pulsars have been discovered, most with periods between .1 and 4 seconds,

mass loss from red giants

the solar wind carries away about 10^-14 of the Sun's mass each year, over the course of 10 billion years the Sun will lose only .01% of its mass this way, in red giant stars it is thought that core instabilities and pulsations are responsible for the large mass loss, a typical red giant loses 10^-7 solar masses a year

cosmology

the study of nature and evolution as a whole, the study of the origin, past, present, and future of the entire universe, our current views were formed in 20th century, Hubble and Humason's Law of Redshifts proved that the universe is expanding and provided the framework for theories of (blank), the cosmological principle holds that the universe is the same everywhere on a large scale -- which we believe is true for superclustering galaxies, cosmologists also assume universality-- the universe obeys the same physical laws everywhere (true)

black dwarf

the theorized final state of a star with a main sequence mass less than about 6 solar masses, in which all of its energy sources have been depleted so that it emits little to almost no radiation, note that a (blank) is not the same thing as a black hole

catastrophic theory

the theory of the formation of the solar system that involves an unusual incident such as the collision of the Sun with another star, proposed by Georges Louis de Buffon in 1745 as a comet pulled material from the Sun to form other planets, we now know comets aren't massive enough to have caused the breakup of the Sun (he was a buffoon), but it was later proposed that the Sun was a part of a triple star system (if stars are very close they can pull matter from their companion) that gave birth to solar system through tidal disruption--> was discredited in 1930s when it was shown that material pulled from the Sun would have been too hot to condense to form planets and would have subsequently dissipated into space, (blank) are rare due to unusual nature if event so this theory has been abandoned while evolutionary has been picked up again, catastrophes prob played only minor role in formation of solar system

mantle

the thick (2,900 km approx. 2200 miles) solid layer between the crust and the Earth's outer core, the crust lies above the (blank), density goes from 3-9 g/cm^3, density goes up as we go towards it center because the weight of the overlying layers squeezes the center

crust

the thin (<100 km approx. 60 miles) outermost layer of the Earth, it is rocky and has a density ranging between 2.5 and 3 g/cm^3 (roughly low and similar to aluminum), is beneath sea floor

synodic period

the time interval between successive similar alignments of a celestial object with respect to the Sun, for the Moon one synodic period is the time between two successive new moons, synodic period/synodic month/lunation/lunar month of moon is 29.5 while sidereal is 27.33 bc lengths of months are variations of 29.5,

eclipse season

the time of year during which a solar or lunar eclipse is possible, only during the two or three eclipse seasons that occur each year are the Earth and Moon positioned so that the Moon will enter the Earth's shadow during a full Moon

solar luminosity

the total rate at which the Sun releases energy into space in all directions, we compute it by multiplying the solar constant by the area of an imaginary sphere radius 1AU --> 4p(1AU)^2 and we assume (blank) is constant though the solar constant isn't constant, is surface area of gigantic sphere of light, (blank) is equal to about 3.9 X 10^33 ergs per second, one erg is enough energy of a flea landing on wrist, sun is fueled by thermonuclear fusion reactions, can measure luminosity and mass, 2 ergs per second per gram= primary set of

Active galaxies and quasars

the tremendous energy that comes from (blank) is caused by an immense black hole at the nucleus of the galaxy, the black hole is surrounded by an accretion disk heated by infalling material that in turn radiates energy mostly in X-Rays, diff types of active galaxies we see are basically the same, and that they appear different depending on their orientation with respect to us, previous (blank) are the ancestors of today's galaxies, quasars are found at the greatest distances because they are the brightest of the active nuclei objects and because they may indeed be older (and thus farther away) than other active nuclei, a competing theory suggests that active galaxies are the result of galactic collisions

radial velocity

the velocity component along the line of sight, toward or away from the observer (Earth), measuring the amount of shifting of stellar spectral lines can determine the (blank) of the star relative to the Earth, measured with doppler effect, easiest measurement to make of stars rather than tangential velocity, 1st made stellar radial velocity measurement was made by W. Huggins in 1868 who studied Sirius, a (blank) curve to plot (blank) of binary stars as a function of time w/ coinciding spectral lines reveals the period and barycenter of binary,

tangential velocity

the velocity component that is perpendicular to the line of sight, the Doppler Effect does not allow us to measure the (blank) of objects, speed across our line of sight and is hard to determine for stars, can be calculated from proper motion and distance

photosphere

the visible surface of the Sun where photons are emitted, is about 400 km in thickness (thin compared to diameter of Sun) gas pressure of outer (blank) is about .01 or air on Earth's surface and Sun's is similar to Mars, density is .001 of density of air at sea level (.01 and .001 bc Sun is so much hotter than Earth), constantly moving layer (granules), by mass its 78% hydrogen 20% helium and 2% of 60 of the heavier elements found on Earth, fluxtube fields through (blank) can increase solar output, when we look at the color of the (blank) we're looking for temperature, (blank) is under chromosphere, fluxtube fields through the (blank) can increase the solar output, spectral line absorption happens here,

fusion reactions

thermonuclear fusion reactions which are constantly converting hydrogen into helium inside the cores of most stars, these (blank) occur when sub atomic particles which comprise diff nuclei interact with each other and energy is liberated when these particles interact to create heavier nuclei, when two nuclei combine to form a larger nucleus releasing energy in the process-- this is a nuclear (blank), in a series of nuclear reactions which occur within the core of the Sun 4 hydrogen nuclei fuse to form 1 helium nucleus and in the process energy in the form of gamma rays is given off, these reactions inside the sun convert only .7% of the original mass of the 4 hydrogen nuclei into energy,

largest meteoroids

these meteoroids are large enough that they are able to pass through the Earth's atm w/out being completely evaporated, solid chunk of matter which remains after the meteoroid passes through atm it is called a meteorite, they can fall on the Moon and other planets, some have landed from Mars and the Moon,

Walter Baade and Fritz Zwicky

these two of Caltech discussed the theory of neutron stars in the 1930s, A typical neutron star: •Mass = 1.5 solar masses •Diameter = 20 km (width of small city) •Density = 10^15 g/cm3 •Temperature = 10,000,000 K

coronal holes

things we saw when X ray photographing Sun to find sources of X Rays in Corona (places hot enough to produce X Rays), large dark areas but aren't holes in corona, instead are places where magnetic field of Sun opens and spurts out like a fountain--> magnetic loops which confine gas are opened up like a fountain and gas is released so temp is at minimum, (blank) occur between active regions, 600,000 Kelvin is temp in (blank), highest speed portions of solar wind originate in (blank), these are important to us bc high speed solar wind streams can impact Earth's climate,

Mercury's magnetic field

this field is only 1% as strong as is the Earth's, suggests part of its metallic core must be molten in order for the dynamo effect to operate but recent measurements of heat loss indicate its core is not molten, field is very weak which must be from the relatively slow rotation rate of this planet

inverse square law of light (and gravity and electromagnetic force)

this law states that light (or radiation) spreading from a small source decreases in intensity as the inverse square of the distance from the source,is proportional to 1/d^2 where d=distance,

Mercury's motions

this planet circles the Sun in 88 days moving at 48 km/s, along with Pluto has the most eccentric orbit (is tilted 17 degrees to ecliptic while other planets aren't tilted > 7 degrees), rotates once every 58.65 Earth days (2/3 of its orbital period)--> spin-orbit coupling, this unusual coupling of rotation and revolution is bc tidal force from sun on Mercury's mass's unbalanced nature (it wouldn't happen if mass were evenly distributed within), has one of most eccentric orbits with Pluto

Venus's motions

this planets orbit is almost circular with a sidereal orbital period of 225 days, sidereal rotation period is 243 days--> solar day is 117 Earth days long, orbital speed is nearly constant at 35 km/s, retrograde rotation (bc axis is tilted > 90degrees)

photosynthesis

this process is used by plant life and is the reason we have free oxygen in our atmosphere now, because the early atmosphere didn't have any

Outgassing

this process was the origin the Earth's atmosphere, in (blank) vents and volcanoes allowed heated gas to escape from the rock of the mantle and crust, Earth belched out its atmosphere, most important gas was water vapor bc this condensed into oceans, 2nd most important gas was C02 which combined with surface rocks to form carbonate minerals, 3rd and 4th important gases were nitrogen and argon--> helped date Earth w/ radioactive decay

special theory of relativity

this theory predicts that the observed behavior of matter is due to its speed relative to the person who makes the observation, this theory applies to two observers who are traveling at constant velocities, Einstein used the result of the Michelson-Morley Experiment as the basis for (blank) which he published in 1905, In this theory Einstein introduced the notion of four-dimensional spacetime in which we treat x,y,z and time equally , the (blank) predicts that the observed behavior of matter is due to its speed relative to the person who makes the observation, this theory applies to two observers who are traveling at constant velocities ie. who are not accelerating, the (blank) also says that all observers will measure the same speed of light regardless of their own motions, as Michelson and Morley had observed, einstein also said that the two observers would disagree on each other's mass, he said that each would perceive the other's mass as being greater than the other would measure it to be, the amount of time by which the masses would appear to increase is directly related to the relative velocity of the two observers, Einstein said that the smallest mass an object would appear to have would be its mass when it was not moving with respect to the observer who was making the measurement, this minimum mass of an object is the rest mass,

super lightweight stars

those stars having masses between 2 and 4 times the mass of the Sun, have massive enough cores that these cores never become degenerate and therefore they do not experience a helium flash, otherwise they evolve like the other lightweight stars,

slow gravitational contraction

thought by kelvin-helmholtz theory to fuel sun but didn't account for age of sun,

Types Ib and Ic

thought to originate from more massive single supergiant stars which have shed their hydrogen layers (hence Type I bc have no hydrogen line spectra), (blank) only occur in regions where recent star formation has occured because these two types of supernovae only come from very young, massive stars,

Earth's magnetic field

thought to originate in Earth's liquid outer core, Earth's magnetic poles are not located at its poles of rotation. Rather, the magnetic axis is tipped by about 11-13o (magnetic obliquity)the location of the magnetic poles changes with time, measuring direction of magnetic field in magnetized rocks tells us the direction (polarity) of (blank) has changed at least 171 times during thr past 76 million years

Detecting Supernovae

three naked eye supernovae that have been seen in our galaxy in recent times occurred in 1054 recorded by Chinese, 1572, and 1604, The supernova of 1572 was seen by Tycho Brahe and the one of 1604 was observed by Kepler, unfortunately both of these supernovae occured just before the invention of the telescope

time dilation

time runs slower near a large mass, einstein used algebra to state that each observer in relative motion at constant velocity with respect to another observer will appear to see that other observer's clock run more slowly than that observer will think his clock is running, the amount of stretching of time is governed by the relative velocity of the two

Micrometeorites

tiny meteorites which still hit the moon, cause moonquakes,

stellar luminosity

total rate at which electromagnetic energy is being emitted in all directions by that star, the total amount of power emitted by that star, measured by ergs/second (just like solar luminosity), distance affects (blank) bc of inverse sq law of light, Hipparchus (greatest pre Christian astronomer) had the 1st star catalog w/ brightness bc babylonians didn't note this (Primarily arabic star names form original middle eastern star catalogs), modern measuring allows astronomers to determine magnitudes to an accuracy of .001 or better, some stars are so bright (Sirius) that they have negative magnitudes, (blank) L can be determined from its absolute magnitude M, It's (blank) is also equal to the product of the energy emitted per square cm per second times the surface area, modern large telescopes equipped with CCD devices can image objects as dim as 25th mag or better,

Van Allen belts

two doughnut-shaped (torus) regions composed of charged particles (protons & electrons) emitted by the Sun & captured by the magnetic field of the Earth. They are located in the earth's magnetosphere, (blank) are named for their discoverer, Dr. James Van Allen of the University of Iowa, who passed away recently, lower (closer to surface of Earth) and upper van allen belts, were discovered by Explorer 1 in 1958, particles don't always stay in Van Allen belts--> sometimes particles travel to Earth's atmosphere (causing aurora)

Trojan Asteroids

two groups (trailing and leading) of asteroids which are located at Jupiter's distance from the sun, but are either 60 degrees in front of or behind Jupiter's location at the vertices of equilateral triangles, they exist there bc their locations are at two points of stability which they reached after a long amount of time, in 2011 scientists discovered 1st (blank) of Earth which they had thought Earth should have had before,

optical doubles

two stars that have a small angular separation as seen from Earth but are not gravitationally linked, the stars in such a pair are at very different distances, they are fake binaries/ optical illusions

RR Lyrae

type of start not as bright and show less variation with shorter periods than cepheids, Harlow Shapely's work led to a period-luminosity diagram for (blank) variables

lunar small iron core

unconfirmed, but has created weak magnetic field

Star Death

until stars' lives end on the main sequence the main difference between the evolution of stars of various masses is the amount of time they spend as protostars and main sequence stars

blink comparator

used by Clyde Tombaugh to compare 2 photos of the sky taken a few days apart, objects will appear to jump from one spot to another in sky, used by Lowell to predict location of pluto, Lowell initiated the search for pluto by studying perturbation theory,

Solar and Heliospheric Observatory (SOHO)

used by Rhodes' research team, one of NASA/ESA spacecrafts, solar spacecraft launched in 1995 still running today which was meant to study the Sun continuously from a point directly between Sun and Earth, one of NASA's more successful missions in terms of duration, carries 3 instruments which were designed to carry out helioseismic studies (2 look at Sun as though it were a star) and other is Michelson Doppler Imager,

Maunder butterfly diagram

used to find locations and relative numbers of sunspots

galactic motions

using the doppler effect to measure the speeds of globular clusters distributed around the center of the Galaxy is one method for determining the motion of the Sun around the galactic center, the Sun is traveling in a nearly circular path around the galactic center at a speed of about 220 km/s (takes about 250 million years to complete orbit)

scalar field

vacuum-like state of pure energy known as (blank), which we now think is beginning of universe,

the path of totality

varies from each eclipse

Heavyweights

very massive stars which are rare, have over 12 solar masses to maybe 120, a star that is 15 times as massive as the sun burns up its hydrogen in only 10 million years (sun lasts 10 billion years in main sequence) because its core temperature is much higher than the Sun's and the reactions run faster, these massive stars then expand to become supergiants with luminosities a million times that of the Sun and absolute magnitudes of -10, (blank) differ from middleweights in what happens to them when their core is compressed to a density greater than electron degeneracy can support, in a middleweight the resulting supernova leaves a neutron star, in a (blank), the core has a mass greater than 3 solar masses and it swallows itself as a black hole, a star with a mass greater than 100 solar masses will emit radiation so intense that it will prevent more material from falling into the star, thereby limiting the star's size, (blank) are like gas guzzling hummers, the core of a (blank) before it becomes a Type II supernovae has a iron core + 6 layers of fusing shells --> the most massive nuclei at the center bc temp is highest here,fusing iron takes energy unlike every other nuclei fusing(hydrogen, helium, berillium is exothermic) while iron is endothermic and sucks energy out of core-> begins to implode and gets past point of electron degeneracy that neutrons become degenerate and implosion turns around resulting in reverse and it explodes after reaching Chandrasekhar limit-> type II Supernovae (neutron star if its middleweight) or (black hole if superweight)

Naked Eye Andromeda

visible eye galaxy, M31, NGC 224, the distance to (blank) was discovered with Cepheid Variables stars by Hubble, is a normal spiral galaxy,

Voyager 1 and 2

visited Jupiter in 1979 (jupiter has had more visits of all gas giants), gave us images of jupiter, voyager 1 discovered thin ring around Jupiter 1.8 planetary radii away, 3 other have been discovered (4 total rings which are replenished by small moonlets around them), Voyager 1 passed saturn in 1980 Voyager 2 in 1981, voyager 2 passed Uranus in 1986 and confirmed 10 thin rings and discovered moons, and then Neptune in 1989 & sent back +9,000 images and photographed Great Dark Spot and 11 new moons, voyager missions taught us most of what we know about outer planets,

Jupiter's magnetosphere

volume of space in which the Jupiter has a huge magnetoshpere motion of charged particles is controlled by the magnetic field, extends 15 million km from jupiter and envelops more of its satellites , pioneer 10 confirmed this

eddies

vortices, it was proposed in 1940s by Carl von Weizsacker showed that (blank) would form a rotating gas cloud and that the (blank) nearer the center would be smaller, (blank) would condense to form particles that would grow over time to become planetesimals which in turn would sweep up smaller particles through collision and gravitational attraction, remnants of small eddies formed comets in outer solar system

Anaxagoras

was before Aristotle, (blank) thought to have explained the reasons for the moon's phases, believed the moon only shines by reflected sunlight and is not luminous (he thought the side away from the Sun would always be dark), he thought Moon was located closer to Earth than was the Sun, described moon's phases in his writings

SN1987A (Supernova 1987 A)

was discovered in the Large Magellanic Cloud (not Milky Way galaxy) in 1987 by Ian Shelton at the Las Campanas Observatory in Chile, it appears that the ejected shell of material was shed by a red supergiant with a mass of about 20 times that of the sun, the star ejected the material about 170,000 years ago, leaving the star with a hotter, bluer surface, an increase in neutrinos was observed some 3 hours before the supernova was seen, confirming an important part of the theory of supernovae

flatness problem

was the inability of the standard big bang model to account for the apparent flatness of the universe,

Gravitational Microlensing Method

watch light of stars brighten to discover extrasolar planets, not the preferred method for this

Transit Photometry method

watching light of stars dim to find extrasolar planets bc star's light is partially blocked out by planet's orbit

run-away greenhouse effect

water on venus didn't condense out of its atm to form oceans but the CO2 was trapped in atm and trapped infrared radiation-> thick clouds and high temps on Venus

first quarter

we only see a quarter of the moon, though the sun is actually illuminating half of it

eclipsing binaries

where one star moves in front of the other as viewed from Earth, such as Algol (discovered by John Goodricke) which has a light curve-- a graph of the numerical measure of the light received from a star versus time-- shows peaks and dips that indicate an unseen companion, the Stefan-Boltzmann law says we're getting diff amounts of obstruction based on dimmer and brighter star and which is in front, (blank) that are also spectroscopic binaries provide us with a way of measuring not only the masses of the two stars but also their sizes, we can derive this info by measuring Doppler shifts during each orbit, orbital plane of two stars is in our line of sight so they appear to eclipse one another from Earth (we need to know inclination of orbital plane), inclination will be approx. 0 degrees, a flat bottom on a light curve indicates total eclipses

ionosphere

where the upper atm is being ionized by solar UV radiation resulting in an inversion layer

standard candles

where we assume each one reaches max limiting brightness and when we compare their brightnesses we are comparing distance, Hubble used Cepheids as standard candles,

solar wind

wind of (electrically neutral gas) ionized gas/plasma that flows from corona of sun, it extends around other planets, as it flows out it pulls a portion of the magnetic field (called the interplanetary magnetic field), highest speed (blank) steams from coronal holes, near Earth the (blank) speeds can reach 400-1000 km/s, while density ranges from 2 -10 particles/cm^3, (blank) knocks some material off mercury to form thin temporary atm, in red giant stars its is thought that the core instabilities and pulsations are responsible for the large mass loss, (blank) is the continuous flow of nuclei and electrons from the Sun, is outermost portion of solar atm, aurorae form when charged particles form the solar wind are trapped by Earth's magnetic field and then strike upper atmic molecules causing them to glow