week 9 review
galaxy
(astronomy) a collection of star systems
Core
(sun's interior) central region, produces enormous amounts of energy, in the process of nuclear fusion (hydrogen joining to form helium). High temperatures & pressure.
Radiation Zone
(sun's interior) next up from the core; middle layer; region of tightly packed gas; energy is transferred in form of electromagnetic radiation. Very dense region
Convection Zone
(sun's interior)top or outermost layer. Gases rise and cool; then sink, forming loops of gas that move energy towards sun's surface. Generates sun's magnetic field.
Hertzsprung-Russel Diagram
A graph relating the temperature and brightness of stars
constellation
A group of stars that form a pattern in the sky
craters
A large round pit caused by the impact of a meteoroid.
continuous spectrum
A spectrum of light in which there are no gaps, so that each region blends directly into the next
red giant
A star that expands and cools once it runs out of hydrogen fuel
cepheid variable
A variable star that brightens and dims regularly, or pulses, and whose distance can be determined from its period of pulsation
red dwarf
A very small star with low temperature, reddish in color
electromagnetic spectrum
All of the frequencies or wavelengths of electromagnetic radiation
Scientific Method
Approach to researching questions and problems through objective and accurate observation, collection and analysis of data, direct experimentation, and replication of procedures.
Aristotle
Believed the Sun moved around the earth and a stationary Earth.
F-type star
Color: White Temp: 6900°C or 12500° F
O-type star
Color: blue Temp: 9400-205040°C or 17000-37000° F
G-type star
Color: light orange Temp: 5540°C or 10000° F
Isaac Newton
Deducing a law of gravity and three general laws of motion that apply to all objects.
H-R Diagram
Hertzsprung-Russell Diagram; used to classify stars and to understand how stars change over time. Shows brightness and temperature
galilean moons
Io, Europa, Callisto, Ganymede
Galilean satellites
Io, Europa, Callisto, and Ganymede the moons around Jupiter.
Neptune
Last planet in the solar system and the fourth gas giant. Windiest planet in the solar system.
Magnitudes
Levels of brightness of stars. Perceived as brightness ratios.
crescent moon
Moon phase in which less than half of the Moon appears to be illuminated
Polaris
North star, star that the stars roatate around
summer solstice
Occurs when the Sun is directly overhead at 23.5° north latitude, around June 21, and results in the maximum number of daylight hours for the northern hemisphere and the minimum number for the southern hemisphere.
winter solstice
Occurs when the Sun is directly overhead at 23.5° south latitude, around December 21, and results in the minimum number of daylight hours for the northern hemisphere and the maximum number for the southern hemisphere.
vernal equinox
Occurs when the Sun is directly overhead at the equator and results in day and night of equal length for both northern and southern hemispheres
celestial pole
One of two points of intersection of the Earth's axis and the celestial sphere
Copernicus
Postulated a heliocentric solar system.
Mars
Red planet with rust on the surface causing the red glow. Fourth planet from the Sun.
protoplanets
Regions of condensed matter that serve as a starting point for the formation of a planet.
protoplanetary nebula
Regions with dense elements collaps due to shockwaves from nearby supernovas. May form planets and stars.
Venus
Second planet from the Sun, but is the hottest because it has a thick atmosphere which traps heat.
Uranus
Seventh planet from the Sun third gas giant. Has strange rotation which is top to bottom.
Saturn
Sixth planet from the Sun. Second of the gas giants with seven large shining rings.
Red Giants
Small & medium-mass stars run out of fuel; their outer layer expands
wavelength
The distance between crests of waves, such as those of the electromagnetic spectrum
magnetic field
The energy field created by the spinning of the inner and outer cores.
Jupiter
The first of the gas giants and fifth planet from the Sun. Largest planet in the solar system. Has great red spot which is a storm.
weight
The force of gravity on an object
penumbra
The lighter outer portion of a shadow cast by a planet or moon, where an observer in the shadow would see a partial solar eclipse
milky way
The name of our galaxy, a spiral galaxy that contains about 400 billion stars
thermosphere
The outermost layer of Earth's atmosphere.
eclipse
The partial or total blocking of one object in space by another
law of universal gravitation
The scientific law that states that every object in the universe attracts every other object.
solstice
The two days of the year on which the sun reaches its greatest distance north or south of the equator
Earth
Third planet from the Sun. Has atmosphere which sustains life.
Law of Nature
Well-confirmed summery statement of how a natural phenomenon behaves. Subject to change.
spring tide
When the Moon and the Sun pull together and create a higher than usual tide; occurs during the full moon and new moon phases
main sequence
a band of stars that includes most stars of average color, size, magnitude, and temperature
solar flare
a brief burst of energy from the sun's photosphere
aurora
a bright display of ever-changing light caused by solar radiation interacting with the upper atmosphere in the region of the poles
meteoroids
a chunk of rock or dust in space
prominence
a concentration of gases above the solar surface that appears as a bright archlike structure
protostar
a contracting cloud of gas and dust with enough mass to form a star
sunspot
a dark area of gas on the sun that is cooler than surrounding gases
sunspot
a dark region on the surface of the sun. Cooler temperatures.
telescope
a device built to observe distant objects by making them appear closer
white dwarf
a faint star of enormous density
solar wind
a fast-moving stream of particles thrown into space by solar flares
nebula
a large cloud of dust and gas that can break apart into smaller pieces and form stars
solar nebula
a large cloud of gas and dust such as the one that formed our solar system
neap tide
a less than average tide occurring at the first and third quarters of the moon
absolute magnitude
a measure of the amount of light that a star actually emits
plasma tail
a narrow, ionized comet tail pointing directly away from the Sun
photon
a particle of electromagnetic radiation having zero mass and carrying a quantum of energy
photon
a particle of light
force
a push or pull exerted on an object
pulsar
a rapidly spinning neutron star that produces radio waves
kuiper belt
a region of the solar system that is just beyond the orbit of neptune and that contains small bodies made mostly of ice
Hubble Space Telescope
a space telescope and camera named for a famous astronaut (Edward Hubble) used to study space elements
oort cloud
a spherical region of comets that surrounds the solar system
nova
a star that ejects some of its material in the form of a cloud and become more luminous in the process
main-sequence star
a star that falls into the main sequence category on the H-R diagram
solar wind
a stream of electrically charged particles produced by the sun's corona
solar nebula theory
a swirling cloud of dust and gas formed. in the center, it was hot and had high pressures where the sun formed. As the outer part of the cloud cooled solid particles condensed forming planets moon, and other solid objects
calendar
a system of organizing time that defines the beginning and length and divisions of the year
binary star
a system of two stars that revolve around each other under their mutual gravitation
reflecting telescope
a telescope that uses a curved mirror to collect and focus light
chromosphere
a thin red region of the sun's atmosphere between the corona and the photosphere; too faint to see unless there is a total solar eclipse
light gathering
ability to make faint objects appear brighter
magnifying
ability to make objects appear larger
resolving
ability to see fine detail
White Dwarf
after a star runs out of fuel, about size of Earth, but with the mass of the sun; still glows from left-over energy
supergiant
an extremely bright star of very large diameter and low density
axis
an imaginary line that passes through Earth's center and the north and south poles, about which Earth rotates
Constellations
an imaginary pattern of stars in the sky
nebula
an immense cloud of gas (mainly hydrogen) and dust in interstellar space
element
any substance that cannot be broken down into simpler substances
Parallax
apparent change in the position of an object resulting from the change in direction or position from which it is viewed.
Sunspots
areas of gas on the sun's surface; cooler than the gas around it; appear darker; helped prove sun rotates on its axis; 11 year cycle; most disappear in two weeks; form where magnetic field is strongest
radio telescope
astronomical telescope that picks up electromagnetic radiations in the radio-frequency range from extra-terrestrial sources
gravity
attractive force between two objects that depends on the masses of the objects and the distance between them
Hipparchus
began the systematic observational work with written records. Determined length of a year. Categorized stars.
heliocentric model
belief that center of solar system is a stationary sun.
geocentric model
belief that center of the solar system is a stationary earth.
astroid belt
belt of rock that orbits the sun usually between mars and jupiter
lunar eclipse
blocking of the moon that takes place when the Earth comes directly between the sun and full moon
Apparent Brightness
brightness as seen from Earth
doppler effect
change in the apparent frequency of a wave as observer and source move toward or away from each other
Characteristics
characteristics used to classify stars: color, temperature; size; composition (elements); and brightness
perihelion
closest approach of a planet to the sun
Mercury
closest planet to the Sun. Very hot rocky planet. tSmall quickly moving planet.
Nebula
cloud of gas and dust; where stars & planets are born
Color
color reveals surface temperature; from coolest: red, light orange, yellow, white and blue
M-type star
color: red Temp: 3038°C or 5500° F
interferometry
combination of multiple signals from smaller telescopes to simulate one image
velocity
constant speed and direction an object moves without external force
solar wind
continuous stream of high-energy particles released into space in all direction from the sun's corona
Sun's Interior
core, radiation zone, convection zone
Pythagoras
credited with summerizing the ideas of geometry, credited with proposing the idea of a spherical earth and moon, by studying eclipses
umbra
dark center of a typical sunspot
maria
dark, flat areas on the moon's surface formed from huge ancient lava flows
Metric System
decimal system of weights and measures in kilogram, meter and liters.
latitude
decrees north or south of the equator
right ascension
degrees east of the vernal equinox
longitude
degrees east or west of the prim meridian
declination
degrees north or south of the equator
Brightness
depends on both size and color; described in two ways: apparent brightness and absolute brightness
How long a star lives
depends on its mass
Life of stars
depends on its mass; the more mass the shorter the life span
Eratosthenes
determined the circumference of Earth from observations by noting the angle of the sun.
aperture
diameter of the lens or mirror used to gather light.
Light year
distance used to measure distance between stars; the distance light travels in one year = 9.5 million km (300,000 k/s)
Protostar
earliest stage in star's life
universe
everything that exists, including the sun, stars, all the planets, and outer space
Scientific Notation
exponential numbers used to express measurement
gas-giant planets
farthest from the sun, large, massive, not dense, mostly gaseous with solid cores, primarily hydrogen and helium chemical makeup, deep and thick atmosphere, cold exterior temperature, fast rotation, many satellites.
Sun Features
features on or just above the sun's surface include sunspots, prominences and solar flares
Angle
formation of two lines that have the same endpoint, measured in degrees.
Aphelion
greatest distance between a planet and the sun
rocky planets
group of four planets in our solar system formed when the Sun melted ice particles creating rocky dense planets.
Prominences
huge reddish loops of gas; often link sunspots; possibly due to the sun's magnetic field
2 main gases found in stars
hydrogen combining to make helium
celestial sphere
imaginary sphere drawn in space with the earth at its center
Photosphere
inner layer of sun's atmosphere; sphere that gives off visible light; gases here are thick; considered sun's surface layer (note: sun doesn't have a solid surface)
Theory
integrated set of statements that explain various phenomena.
When a star runs out of fuel
it becomes a white dwarf, a neutron star, or a black hole
outer planets
jupiter, saturn, neptune, uranus
galaxy
large group of stars, gas, and dust held together by gravity
Ptolemy
last Greek astronomer. Formulated an explanation of a geocentric model
chromosphere
layer immediately outside the photosphere, pinkish in color. The region seen during a solar eclipse where the photosphere is blocked from view.
light year
light distance travels in one year (9.5 trillion km)
light-year
light distance travels in one year (9.5 trillion km)
penumbra
lighter outer area of a typical sunspot
photosphere
lowest layer of the Sun's atmosphere and the layer that gives off light
nebulae
massive clouds of dust and gases where stars are born
Mass
measure of the quantity of material in an object
Tacho Brahe
measured accurately the positions of celestial objects
Right angle
measurement of 90 degrees
inner planets
mercury, venus, earth, mars
planets
mercury, venus, earth, mars, jupiter, saturn, uranus, neptune, pluto
Chromosphere
middle layer of sun's atmosphere; visible during a total solar eclipse; called the color sphere
new moon
moon phase that occurs when the Moon is between Earth and the Sun, at which point the Moon cannot be seen because its lighted half is facing the Sun and its dark side faces Earth
Size
most stars are med-sized; from smallest: neutron, white dwarf, star (low and high mass); red giant; super giant
redshift
motion of light away from the observer are measured longer or redder.
blueshift
motion of light toward the observer when wavelengths are measured shorter or bluer
spicules
narrow jet like fountains rising out of the solar atmosphere
terrestrial planets
nearest to the sun, small size, non-massive, dense, structure solid with iron cores, chemical composition heavy elements, thin atmosphere, warm exterior temperature, slow rotation, few satellites
Aurora Borealis
northern lights; caused by solar wind
Eighty-eight
number of constellations
Six thousand
number os stars visible to unaided eye
astroid
object in orbit around the sun; in reference to size, between meteroids and planets
Black Hole
object with strong gravity that doesn't allow anything, including light, escape; a possible last stage in a high mass star
momentum
objects mass times its velocity
Solar Wind
occurs in the corona; solar flares increases this; responsible for increase in number of magnetic particles reaching Earth's atmosphere; create powerful electric currents that result in greenish, red or purple glow in Earth's sky (called auroras); can also cause magnetic storms
solar eclipse
occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth
phases
one of the different apparent shapes of the moon as seen from Earth
Galileo Galilei
one of the first people to use a telescope. Discovering craters on the moon, Jupiter's satellites, Milky Way stars.
refracting telescope
optical telescope that has a large convex lens that produces an image that is viewed through the eyepiece
Corona
outer layer of sun's atmosphere; visible during total solar eclipse; looks like a halo around the sun; extends into space for millions of km; gradually thins into think streams of electrically charged particles called solar wind.
Ellipse
path of a point that moves so that the some of its distances from two fixed points (foci) is constant.
Astronomers
people who study the universe including origins, evolution, composition, motions, positions and celestial bodies.
Sun's Atmosphere
photosphere, chromospheres, corona
Nebula into
planet, brown dwarf, low or intermediate mass star, or a massive star
gas giants
planets farther from the Sun's heat where ice particles combined with gas creating larger lighter planets.
zenith
point right above you
vernal equinox
position of the sun on the first day of spring.
background radiation
radiation left over from the beginning of the universe
Neutron Star
remains of high mass stars; smaller and denser than white dwarfs
black hole
remnant of a star that is so dense that nothing, not even light, can escape its gravity field
Pulsars
short for pulsating radio sources; spinning neutron stars
Lifecycle
shows the stages of birth and death of stars; two different paths according to original mass of star.
meteoroids
small, rocky objects that orbit the sun in both the outer and inner regions of the solar system
Aurora Australis
southern lights; caused by solar winds
comet
space object made of dust and rock particles mixed with frozen water, methane, and ammonia that forms a bright coma as it approaches the Sun
emission spectrum
spectrum of electromagnetic radiation emitted by a self-luminous source
circumpolar stars
stars that can be seen at all times of the year and all times of night.
Law of Inertia
states that an object continues moving at the same rate unless acted upon by external force.
meteorite
stony or metallic object that is the remains of a meteoroid that has reached the earth's surface
Astronomy
study of the stars involving the study of the universe and every object in the universe.
Solar Flares
sudden bursts of energy in the form of fire that erupts on the sun's surface; happens when sunspot loops connect and release huge amounts of magnetic energy
highlands
tall mountain ranges and appear as light areas on the moon
optical telescopes
telescopes used to view visible light
corona
tenuous, and hot, outer atmophere with temperatures 1-2,000,000 K. With bright light emissions
Hypothesis
testable prediction
mass
the amount of matter in an object
parallax
the apparent change in position of an object when seen from different places
solar eclipse
the blocking of sunlight to Earth that occurs when the moon is directly between the sun and Earth
lunar eclipse
the blocking of sunlight to the moon that occurs when Earth is directly between the sun and the moon
Absolute Brightness
the brightness a star would have if it were a standard distance from Earth
magnitude
the brightness of a star
apparent magnitude
the brightness of a star when viewed from Earth
supernova
the brilliant explosion of a dying supergiant star
blue shift
the decrease in wavelength of light due to an object toward the observer
Composition
the elements found in stars; most are hydrogen and helium and a small percentage of other elements (like sodium & calcium); astronomers use spectrographs to determine this.
Supernova
the explosion of a supergiant star; this material may become part of a nebula
projection effect
the fact that the stars of a constellation may be located or not located at different distances from us.
red shift
the increase in wavelength of light due to an object moving away from the observer
umbra
the inner, darker part of a shadow
troposphere
the layer closest to Earth, where almost all weather occurs; the thinnest layer
mesosphere
the layer of the atmosphere between the stratosphere and the thermosphere and in which temperature decreases as altitude increases
stratosphere
the layer of the atmosphere that is above the troposphere and in which temperature increases as altitude increases
meridian
the line from north from zenith to south
coma
the luminous cloud of particles surrounding the frozen nucleus of a comet
precession
the motion of a spinning body (as a top) in which it wobbles so that the axis of rotation sweeps out a cone
revolution
the movement of an object around another object
corona
the outer layer of the sun's atmosphere
corona
the outermost region of the sun's atmosphere
orbit
the path of an object as it revolves around another object in space
tide
the periodic rise and fall of the level of water in the ocean
waning moon
the phase of the Moon when a decreasing amount of the Moon's near side is sunlit
waxing moon
the phase of the Moon when an increasing amount of the Moon's near side is sunlit
quarter moon
the phase of the Moon when half of the Moon's near side is sunlit
horizon
the plane you stand on
nuclear fusion
the process by which hydrogen atoms join together to form helium, releasing energy occurs in the core of the sun
chromatic abberation
the rainbow effect when light is dispersed through lens
convective zone
the region of the sun's interior in which energy is circulated by density differences
Newton's first law of motion
the scientific law that states that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted on by a force
neutron star
the small, dense remains of a high-mass star after a supernova
absorption spectrum
the spectrum of electromagnetic radiation that has passed through a medium that absorbed radiation of certain wavelengths
rotation
the spinning motion of a planet on its axis
Archaeoastronomy
the study of the astronomy of ancient cultures. Including ancient structures, early calendars, navigation, and mathematics EX: stone henge at the summer solstice
astronomy
the study of the moon, stars, and other objects in space
spectroscopy
the study of the spectra of stars by analyzing the spectral properties of the light they give off
solar system
the sun with the celestial bodies that revolve around it in its gravitational field
inertia
the tendency of an object to resist any change in its motion
light-year
the time light travels in a year
full moon
the time when the moon is fully illuminated
equinox
the two days of the year on which neither hemisphere is tilted toward or away from the sun
photosphere
the visible surface of the sun
luminosity
total energy emission of the sun, 2x10 to the twenty-six watts.
Johannes Kepler
used Tycho's figures to perform an analysis of planetary orbits.
Aristarchus
used a few simple observation to develop the first valid idea of the scale of the universe.
objective lens
used in refactors to collect light
primary mirror
used in reflectors to collect light
angles
used to denote the positions and apparent sizes of objects in the sky
reflecting telescope
uses a concave mirror to gather light
refracting telescope
uses a lens to ben the light to produce an image
eyepiece lens
uses light to bring the image to a focus
Constellations
well defined regions on the sky, made up of the presence or absence of bright stars in that region
focus
when light waves are coming from the same direction to a single point
meteors
when meteoroids enter Earth's atmosphere. Shooting star
prominences
when seen near the solar limb
plages
when seen superimposed on the solar disk
A star is born
when the contracting gas and dust from a nebula become so dense and hot that nuclear fusion starts
gibbous moon
when the size of the illuminated portion of the moon is greater than half but not a full moon
solstice
when the sun's apparent position from the sky reaches its northernmost and southernmost extremes.
equinox
when the tilt of the earth axis is inclined neither away nor towards the sun.
Black Dwarf
when white dwarf stops glowing
local sky
your view of the celestial sphere depending on your location
