Astronomy
Halley's Comet was given that name because Edmond Halley was
the scientist who predicted that the comet would return every 76 years
aperture
the size of the opening of an optical instrument, for your eyeball about 15mm
Which of the following is not a type of electromagnetic wave with lower energy than visible light waves?
the sound waves coming from your transistor radio
The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:
the zodiac
Edwin Hubble developed a classification scheme for galaxies that looked like a tuning fork. By what characteristic did he classify galaxies?
their shape, elliptical or spiral
Why do satellites launched into low-Earth orbits not remain there indefinitely
they lose speed due to friction with the upper layers of the Earth's atmosphere
Your sweetheart gives you a piece of gold jewelry as a present to celebrate your passing your astronomy class. Where did the gold atoms in that gift originally come from (where were they most likely made)?
they were built up from smaller nuclei during a supernova explosion
interstellar dust
tiny particles that float between the stars and make up a large portion of the mass of the galaxies
when one astronomical object moves in front of another
transit
a supernova formed when a white dwarf exceeds 1.4 solar masses and has causes standard sized explosion. This is useful as a standard candle to determine distance.
type Ia (one-Aye) supernova
a binary star that can be seen in a telescope
visual binary
Astronomers identify the "birth" of a real star (as opposed to the activities of a protostar) with what activity in the star?
when nuclear fusion reactions begin inside its core
From a scientific perspective, which of the following statements about life elsewhere in the universe is best supported by current evidence?
while we have evidence of the building blocks of life elsewhere in the universe, we have no definite evidence about life around other stars at this time
the leftover dense hot core of a star
white dwarf
In 2013, a small stony asteroid collided with the Earth above the Russian city of Chelyabinsk. What was the result?
A fireball briefly brighter than the Sun could be seen in the sky and smaller pieces rained down in the region
Credit for the purely mathmatical discovery of Neptune is shared by two astronomers. They are
Adams and Leverrier
The astronomer who, at the turn of the century, measured the spectra of hundreds of thousands of stars, leaving a catalog that astronomers used for the rest of the century, was
Annie Cannon
Which ancient Greek thinker suggested (long before Copernicus) that the Earth is moving around the Sun?
Aristarchus
1.4 solar masses, beyond which a star's core can not support its own mass with degeneracy pressure
Chandrasekhar Limit
The comet-hunting astronomer who made a list of over 100 nebulae and galaxies that could be mistaken for comets was
Charles Messier
The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was:
Copernicus
A progressive series of techniques that allow astronomers to stretch the maximum distances from Earth that can be measured
Cosmic Distance Ladder
A star's lines ALL appear to be moved toward the red side or blue side of the rainbow
Doppler Shift due to a star moving through space
A star's lines appear to be fatter like a bell curve and reduced in intensity
Doppler Shift due to a star's rotation
The telescope maker and astronomer whose craftsmanship was considered the highest in his era
Fraunhofer
The astronomer whose measurement of a star's actual distance from the Sun was accepted as the first accurate parallax
Fredrich Willhelm Bessel
The first person who regularly turned a telescope to astronomical observations (and published his observations) was
Galileo Galilei
The scientist who made the first telescopic survey of the Milky Way and discovered that it is composed of a huge number of individual stars was
Galileo Galilei
The four large moons of Jupiter were first discovered by
Galileo with his early telescope
Why do many people consider Isaac Newton one of the greatest scientists who ever lived
He formulated the laws that govern all motion in the universe, He combined the work of Galileo, Brahe, and Kepler into one framework, He figured out the mathematical form of a law of universal gravity, he invented a new mathmematics called calculus in order to model his laws of motion
Who was the astronomer who is the "H" in H-R diagram?
Hertzsprung
a constant in the Hubble Law that relates the velocity (red shift) of remote galaxies to their distance
Hubble constant
a rule that the radial velocity of remote galaxies are proportional to their distance from Earth
Hubble's Law
A star spectral lines appears to be very strong in the red but the blue lines seem fainter that you would expect
Interstellar Reddening
The change in color of a star because its view is blocked by grains of dust
Interstellar Reddening
the last element that can fuse in the core of a star because the reaction sucks heat away, causing the star to collapse
Iron
Why is an absorption spectrum especially useful for astronomers?
It has dark lines in it that allow astronomers to determine what elements are in the star
The scientist who formulated the three laws of planetary motion by analyzing the data on the precise location of planets in the sky was
Johannes Kepler
The largest planet in the solar system (by mass) is
Jupiter
Sunspot
Large features seen on the surface of the Sun caused by increased magnetic activity
Doppler Effect
Light and Sound waves shift depending on if the source is moving toward or away from the observer
The total power output of a star
Luminosity
A Star's mass goes up, so does its power output
Mass Luminosity Relationship
the band of light encircling the sky
Milky Way Galaxy
The astronomer who assisted Edwin Hubble at the Mount Wilson Observatory and helped him establish the expansion of the universe was
Milton Humason
The first human being to step out onto the surface of another world was
Neil Armstrong
a type of star explosion that happens in a binary star that is repeatable and does not destroy the white dwarf or its companion
Nova
the hottest burning, largest, and quickest stars to die
O type stars
Your weird cousin, who is really into astronomy, decides that the return address he uses on his letters is incomplete! To his city, state, and country, he begins to add: "North America, Earth, Solar System..." If he now wants to include the name of the Galaxy s spiral-structure feature in which the Earth is located, how should his address end?
Orion Spur
The relationship found in Cephid Variables that allows astronomers to determine their distance from Earth
Period Luminosity
The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is:
Ptolemy
The astrophysicist who first calculated the highest mass that a dying star can have and still be a white dwarf was
S. Chandrasekhar
The comet that broke into more than 20 pieces and then collided with Jupiter in 1994 was
Shoemaker-Levy 9
A way to group stars by the lines that appear in their spectrum
Spectral Class
A star's Hydrogen and Helium lines appear thicker that all the rest
Stark Effect
Which part of the Sun has the greatest density?
The core
Astronomers have concluded that the Sun's activity varies in an 11-year cycle. Which of the following statements about this cycle is TRUE:
The number of sunspots gets larger and smaller over the course of 11 years
local bubble
The skin of the balloon of dust around the solar system caused by outgoing solar winds
The 17th century astronomer who kept a roughly 20 year continuous record of the positions of the Sun, Moon, and planets was
Tycho Brahe
What specific event really made it possible for the three laws of planetary motion to be discovered
Tycho Brahe died and his assistant was able to get full access to his data
a type of star explosion that happens after a massive star core begins to produce iron
Type II supernova
a type of star explosion that turns a white dwarf into a neutron star and likely destroys its binary companion
Type la Supernova
Which of these worlds is the most active geologically?
Venus
A star's spectral lines appead to have oval 'wings' around the line
Zeeman Effect
An idealized object that does not reflect or scatter any radiation that hits it, but simply absorbs every bit of radiation that falls on it is called
a blackbody
When a chunk of cosmic material the size of a golf ball or a baseball hits the Earth s atmosphere it makes a
a fireball that we call a meteor or a shooting star
solar wind
a flow of charged particles leaving the Sun
A type of star cluster that contains mostly very old stars is
a globular star cluster
Plasma
a hot ionized gas (meaning the atoms have fewer or no electrons bout to them)
The Orion Nebula is
a large cloud of gas and dust illuminated by the light of newly formed stars within it
In a radio telescope, the role that the mirror plays in visible-light telescopes is played by
a large metal dish (antenna)
Prominence
a large, bright, gaseous feature that appears above the surface of the Sun and extends into space
telescope
a light bucket designed to direct as many photons as possible at a detector
According to the formula E=mc2
a little bit of mass can be converted into a substantial amount of energy
Who pays the bill for the energy generated by nuclear fusion in the Sun? In other words, where does the energy pouring out of the Sun come from ultimately?
a little bit of mass is lost in each fusion reaction and is turned into energy (the Sun is losing mass)
The largest visible-light telescopes in the world use what device to collect as much light as possible before the light is brought to a focus (to act as the light bucket )?
a mirror
What happens as an electron falls from a higher level to a lower level in an atom?
a photon is given off
coronal hole
a region in the Sun's outer atmosphere that appears darker because there is less hot gas there
The Local Bubble is
a region of low density interstellar gas extending several hundred LY around the Sun
This chapter discusses that light sometimes acts like a photon. What is a photon?
a self-contained packet of electro-magnetic energy
A star moving toward the Sun will show
a shift in the spectral lines toward the blue end (as compared to the laboratory positions of these lines)
coronal mass ejection
a solar flare in which immense quantities of coronal material is ejected at high speed into space
solar flare
a sudden and temporary outburst of electromagnetic radiation from an extended region of the Sun's surface
refractor
a telescope that bends light using a glass lense
radio telescope
a telescope that focuses electromagnetic radiation that is to low of frequency to be seen by the eyes
reflector
a telescope that uses a large mirror to bend the light to a focus
According to the fossil record, how old is the oldest evidence of life forms on the surface of the Earth
about 3.5 billion years
The brightness of stars seen at a standard distance of 10 parsecs
absolute magnitude
To go from a lower level in an atom to a higher level, an electron must
absorb a photon of energy
One way in which the ozone layer is useful for life forms on the Earth's surface is that it
absorbs ultra-violet light, preventing much of it from reaching the surface
Which of the following can astronomers learn from studying the spectrum of a star?
all of these can be learned from studying the spectrum
spectrograph
an instrument attached to a telescope that divides light into its component parts or spectrum
The brightness of stars as we see them from Earth
apparent magnitude
Planets in the habitable zone of their stars
are at a temperature where water can exist as a liquid
The laws of nature as determined by science
are constructed from many observations, hypotheses, and experiments, apply both on Earth and among the stars, and are often written in the language of mathematics (all of the above)
From a city in the U.S., where in the sky would you look to see one well known star that does not appear to turn with the all the others?
at the north celestial pole
How fast do electro-magnetic waves travel?
at the speed of visible light
What happens in the process of fluorescence?
atoms absorb ultraviolet rays and convert them to visible light as their electrons cascade to lower energy levels
Why are the largest craters we find on the Moon and Mercury so much larger than the largest craters we find on the Earth?
because the largest craters were made early in each world's history before the atmosphere thickened, and geologic activity has erased most traces of this early period on the Earth's surface
Why can a star with a mass like our Sun not fuse (produce) further elements beyond carbon and oxygen?
because they just cannot get hot/close enough for the fusion of heavier nuclei because it lacks mass and stronger gravity
Two stars that are physically associated (rotate around each other in space) are called
binary stars
Fission
breaking up of heavier atomic nuclei into lighter ones
Fusion
building up of heavier atomic nuclei from lighter ones
molecular clouds
bunched up interstellar dust that can stretch for many light years across
How did Henrietta Leavitt calibrate her period-luminosity relationship for Cepheid variable stars? In other words, how did she make the general idea into a numerical rule?
by finding cepheids in star clusters whose distance was known in another way
the central part of the Milky Way in the direction of Sagittarius
central bulge
Astronomers now understand that the dark regions or rifts visible in parts of our Galaxy that are otherwise crowded with stars are caused by
clouds with a considerable amount of dust which blocks the light of the stars behind them
The most basic function or operation of an astronomical telescope is to
collect as much light as possible and bring it to a focus
A measure of how blue or red a star appears
color index
Short-period comets like Comet Halley
come back again and again at predictable intervals
The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called:
constellations
Which part of the Earth has the greatest density?
core
Which part of the Sun's atmosphere is the hottest?
corona
the mass in the Milky Way that extends well beyond the boundary of the luminous stars to a distance of at least 200,000 light years
dark matter halo
The part of your GPS location expressed in the number of degrees north or south of the Earth's equator is equal to your latitude. The equivalent coordinate for stars is called
declination
the idea that different parts of the Galaxy turn at different rates
differential galactic rotation
The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to
do experiments and observations about the predictions of the hypothesis
The fact that each type of atom has a unique pattern of electron orbits helps explain why
each type of atom shows different absorption or emission spectra
a galaxy whose shape is an ellipse and contains no observable interstellar dust
elliptical galaxy
Radiation
emission of energy as electromagnetic radiation or photons, also the name for the transmitted energy itself
In the Sun, when a positron and an electron collide, they will produce
energy in the form of a gamma ray
To leave the gravitational pull of the Earth, and explore other planets, probes must have at least
escape velocity
Of the people who stepped foot on the Moon, how many trained originally in their careers to be scientists?
exactly one
a planet orbiting a star other than the Sun
exoplanet
What method would astronomers use to find the distance to a galaxy so far away that individual stars are impossible to make out (resolve)?
finding the red¬shift and using Hubble's Law
What phase of the Moon must it be to have a lunar eclipse?
full moon
Neutrino
fundamental particle that has no charge and a mass that is tiny relative to an electron
a large cold interstellar cloud with a diameter of dozens of light years
giant molecular cloud
a cluster of stars that is old, lacks blue stars, and is found mostly above and below the disk of the Milky Way
globular cluster
round compact groups of stars
globular clusters
the outermost extent of our Galaxy, containing stars and globular clusters in a more or less spherical distribution
halo
If mid-sized stars with masses like our Sun s cannot make elements heavier than oxygen, where are heavier elements like silicon produced in the universe?
heavier elements are made in the cores of significantly more massive stars than the Sun, which can get hotter in their core and have greater gravity
cosmic rays
high energy particles from all around the milky way that strike the Earth
solar wind
high energy particles from the Sun which strike the Earth, planets and other objects in the solar system and extends out into space in a sphere.
a Jupiter sized planet that orbits close to its star
hot Jupiter
When an astronomer rambles on and on about the luminosity of a star she is studying, she is talking about
how much energy the star gives off
By far the most abundant element in the giant (jovian) planets is
hydrogen
Studies of the spectra of stars have revealed that the element that makes up the majority of the stars (75% by mass) is
hydrogen
The most common element in the Sun is
hydrogen
A main difference between asteroids and comets is that asteroids are mostly made of rock and comets are mostly made of
ice
If you want to find stars that are just being born, where are the best places to search?
in giant molecular clouds
Where would you look for the youngest stars in the Milky Way Galaxy?
in the disk with the dust and nebula clouds
When an atom has lost one or more electrons, it is said to be
ionized
a galaxy without any clear symmetrical shape
irregular galaxy
As astronomers have learned more about the structure of the Sun, they have found that it.
is made entirely of hot gas
At the largest and most modern astronomical observatories on Earth today, which of the following regularly happens to the image formed by the telescope?
it is recorded using an electronic detector called a CCD for later analysis
How long a main sequence star remains on the main sequence in the H-R diagram depends most strongly on
its initial mass
When a star settles down to a stable existence as a main-sequence star, what characteristics determines where on the main sequence in an H-R diagram the star will fall?
its mass
Which of the following is a way that the planet Mercury is similar to the Moon?
its surface is heavily cratered
Aurora
light in the ionosphere excited by charged particles from the Sun
Astronomers now realize that active regions on the Sun are connected with
loops of magnetic field emerging from the surface of the Sun
the diagonal line on the HR diagram
main sequence
the point in the plot of a cluster of stars where some start aging into red giants
main sequence turn off
An astronomer discovers a new star and wants to measure its temperature. She would typically do this by
making a blackbody curve and finding the wavelength of the peak (maximum)
a property of binary stars determined by their period of rotation and Kepler's Laws
mass
the property of a star that determines its destiny and eventual death
mass
the ratio of total mass of a galaxy to its light output (Luminosity) which can aid in determining its distance
mass-to-light ratio
The planet Neptune was discovered by means of
mathematical calculations of how it was perturbing the motion of a neighbor planet
The lakes found in the north polar region of Titan are filled with liquid
methane
In terms of numbers, the most common life-forms on Earth today are
microscopic creatures, too small to see with our eyes
a planet of intermediate size between Earth and Neptune
mini-Neptune
According to the geocentric view, everything in the heavens had to go around the Earth, which was the center of the universe. What objects did Galileo discover with his telescope that clearly didn't go around the Earth?
moons around the planet Jupiter
Convection
movement caused within a gas or liquid by hotter less dense matter rising and colder denser matter sinking under the influence of gravity
You are on a camping trip, far away from city lights. You look up into the dark night sky, and see lots of stars, some brighter, some dimmer. All the stars you see with your unaided eye are
nearby in the Milky Way Galaxy
What phase of the Moon must it be to have a solar eclipse?
new moon
Astronomers first detected the presence of a wind of particles coming from the Sun by
noting the wind's effects on the tails of comets
loosely gathered stars born in nebula clouds in the galaxy
open clusters
The canals that late 19th and early 20th observers thought they saw on Mars turned out to be
optical illusions
the shift in distance of one object in comparison to a more distance object, useful to determine their actual distances away
parallax
Positron
particle with the same mass as an electron but positively charged
how fast binary stars rotate around each other
period of rotation
a dying star that is shedding its outer shell and looks like a planet when seen from Earth
planetary nebula
a star containing heavy elements, typically young and found in the disk of the galaxy
population I (one) star
a star with very low abundance of heavy elements, found throughout the galaxy
population II (two) star
Conduction
process by which heat is directly transmitted through a substance when there is a difference in temperature
A star's motion across the sky as seen from Earth
proper motion
balls of nebula gas that will soon become stars
proto-stars
a very young star still in the process of formation
protostar
A star's motion toward or away from Earth, determined by its Doppler Shift
radial velocity
the slowest burning and longest living type of star
red dwarf
When a star or galaxy is moving away from us, we observe the Doppler effect by seeing the lines in its spectrum
red-shifted (shifted toward the red end of the light spectrum)
Photosphere
region of the solar atmosphere from which continuous radiation escapes into space
When a planet temporarily moves westward in the sky over the course of several weeks or months (instead of eastward, as it typically does), we call it:
retrograde motion
In locating objects on the celestial sphere, we call the spacing east or west that something is from Greenwich, England its
right ascension
If you want to locate someone precisely on the surface of the Earth, you specify her exact latitude and longitude. If you want to locate a star precisely on the sky, you need to specify its exact
right ascension and declination
proton-proton chain
series of thermonuclear reactions by which nuclei of hydrogen are built up into nuclei of helium
According to the theory of plate tectonics
slow motions within the mantle of the Earth move large sections of the crust around
The combination of motions of a star that give its total motion relative to Earth
space velocity
Our Milky Way Galaxy is what type of galaxy?
spiral
a spiral shaped region characterized by relatively dense interstellar material and young stars
spiral arm
a galaxy whose shape is a flattened rotating disk with pinwheel like arms of interstellar material and young stars
spiral galaxy
An astronomer who is observing visible light from a glowing cloud of gas in space uses an instrument called a spectrometer which contains a grating with thousands of grooves on its surface. What will this instrument allow our astronomer to do?
spread out the light from into a spectrum
Two stars have the exact same luminosity, but star Y is four times dimmer looking that star X. This means that
star Y is twice as far away as star X
Large amounts of Electromagnetic Radiation caused by fusion
starlight
reddening
starlight that is blocked is often blue, making the stars behind a cloud appear to be red
The process of birth, life, and death of a star
stellar evolution
the energetic outflow of gas from a star
stellar wind
a planet larger than Earth found around another star
super Earth
the object in the center of most large galaxies so massive and compact that light cannot escape from it
suppermassive black hole
An H-R Diagram plots the luminosity of stars against their
surface temperature/ spectal class
What method was used to discover Pluto in 1929-1930?
take pairs of photographs several days apart and "blink" them
A type of star that has turned out to be extremely useful for measuring distances is
the Cepheid variables
If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?
the Earth's axis is tilted by about 23 degrees from the vertical
As a cluster of stars begins to age, which type of star in the cluster will move off the main sequence of the H-R diagram first?
the O and B type stars
Why does the Moon show phases in the course of a month?
the angle the Moon makes with the Sun changes and we see differing amounts of reflected sunlight
An astronomical unit is
the average distance between the Earth and the Sun
hydrostatic equilibrium
the balance between the weights of different layers, as in a star or Earth's atmosphere, and the pressures that support them
Astronomers believe that the center of our Galaxy has a black hole with enough mass inside to make almost 4 million Suns! How do astronomers think a black hole could acquire so much mass?
the center of our Galaxy is a much more crowded region than where the Sun is found due to strong gravity; we still see material falling toward the center and material has fallen in for billions of years
When a knowledgeable amateur astronomer tells you that she has a 14-inch telescope, what does the number 14 refer to?
the diameter of the primary lens or mirror
A light year is
the distance that light travels in one year
Scientists now understand that the Earth consists of layers, with the densest materials in the core. What allowed the differentiation of the Earth s layers to happen?
the early Earth was so hot it was like a liquid and heavier elements sank to the middle
Which of the following is evidence for volcanic activity on Venus?
the fact that the lava plains are only 500 million or so years old, the existence of large volcanic mountains such as Sif Mons, the discovery of thousands of small volcanic cones of the surface of Venus, the pancake domes of Venus
Edwin Hubble was able to show that (with the exception of our nearest neighbors) the farther a galaxy is from us, the
the faster it is moving away from us
The Drake Equation allows astronomers to estimate
the number of probable civilizations out among the stars with which we might communicate
Corona
the outermost (hot) atmosphere of the Sun
detector
the part of a telescope that the photons strike which builds up an image over an exposure time
The Sun's photosphere is
the part of the Sun from which the light comes that we see when we look at the Sun with our eyes
Chromosphere
the part of the solar atmosphere that lies immediately above the photosphere
Baryonic Cycle
the process sort of like the evaporation of clouds on Earth where dust becomes stars becomes dust
The process by which Venus became so much hotter than the Earth is called
the runaway greenhouse effect