| Question |
Answer |
| Constellations |
groups if stars named by ancient cultures to honor gods, animals, legends, etc. |
| How many constellations are in whole sky? |
88 |
| The stars appear to rotate around _____. |
Polaris |
| What causes the stars in the night sky to rotate? |
The rotation of the Earth. |
| What do you call stars and constellations that never set? |
circumpolar (the rotate around the pole. Circumpolar stars rotate around Polaris in the Northern Hemisphere. |
| How do the stars move at the North and South pole? |
horizontally |
| How do that stars move at the equator? |
Vertically. |
| How do stars move at mid-latitudes? |
Diagonally,on an arc across the sky. |
| Will the sun appear to move with respect to the constellations? |
Not in a day, but it will appear to have moved over the course of months or a year. |
| What are the 12 constellations the sun moves through in a year called? What is this path called? |
The zodiac. Ecliptic. |
| Precession |
Why your sign is wrong. Rotation of the Earth's axis itself; makes one complete circle in about 26,000 years. |
| Sidereal year |
Time for Earth to orbit once around the Sun, relative to fixed stars. It follows constellations. |
| Tropical year |
Time it takes for the Earth to be in the same configuration with respect to the Sun again (as opposed to distant stars). It follows seasons. |
| What will happen to the "summer triangle" in 13,000 years? |
It will be a winter constellation |
| Asterism |
Pattern of stars seen in Earth's sky which is not an official constellation. |
| Alpha Orionis |
Second brightest star in Orion |
| Messier Catalog |
An early listing of nebulae, star clusters, and deep sky objects that might have been confused with comets by users of small telescopes |
| Why don't many professional astronomers know the constellations? |
Because big telescopes can only look at small portions of the sky. |
| The pattern of rotation that stars make in the sky depends on your _____. |
Position. |
| What causes night and day? |
The earth's rotation on its axis. |
| Solar day |
Average time between consecutive "noontimes" |
| What defines a year? |
The revolution of the Earth around the Sun. |
| Ecliptic |
Path the Earth's motion around the Sun traces on the Celestial Sphere |
| T/F The sun is lower in the sky in the winter. |
True |
| Equinoxes |
Sun crosses the celestial equator (twice-- Spring & Fall) |
| Solstices |
Sun's farthest northernly or southernly position. (summer or winter) |
| Ecliptic |
Path that the sun follows in the sky. 23.5 degrees to the celestial equator |
| Northernmost point above the celestial equator |
Summer solace |
| Southernmost point below the celestial equator |
Winter solace |
| Points where paths cross celestial equator |
Vernal & autumnal equinoxes |
| Time from one vernal equinox to the next |
Tropical year |
| Season |
combination of day length and sunlight angle |
| Moon's revolution around the earth causes: |
Lunar phases, eclipses, tides |
| Synodic month |
moon takes about 29.5 days to go through whole cycle of phases |
| Phases are due to |
different amounts of sunlit portion being wisible from Earth |
| Lunar Eclipse |
moon disapears |
| Solar Eclipse |
sun disappears |
| Lunar eclipses occur when |
the moon enters the shadow of the earth |
| Umbra |
all sunlight blocked |
| penumbra |
only some sunlight blocked |
| total eclipse |
all of moon in umbra |
| partial eclipse |
only part of moon in umbra |
| penumbral eclipse |
moon only in penumbra |
| Solar eclipses occur when |
the Earth enters the shadow of the moon (moon blocks the sun" |
| Annular eclipse |
moon doesnt cover the whole sun |
| Why arent eclipses more frequent? |
The moon's orbit around the Earth is tilted so the Earth's orbits and the Moon's orbits are not in the same plane. |
| # solar eclipses per year |
at least 2, no more than 5 |
| #Lunar eclipses per year |
maximum is 3 |
| # combined eclipses per year |
maximum is 7 |
| maximum duration of Solar eclipse |
7 1/2 minutes |
| maximum duration of lunar eclipse |
1 hour 47 minutes |
| Spring tide |
when tides from the sun and moon combine |
| Neap tide |
when the tides from the Sun and Moon counteract eachother |
| How many high tides are there per day? |
2 |
| Lunar phases during which tides are particularly strong |
New Moon & Full Moon |
| Region between Mars and Jupiter |
Asteroid belt |
| Asteroids |
large chunks of rock and metal left over from the formation of the solar system |
| Meteroids |
small asteroids. most are less than 1mm in diameter |
| Meteors |
flash you see when a meteoroid hits the Earth's atmosphere and gets burned up. |
| Meteorites |
pieces of meteoroids that make it thought the Earth's atmosphere without burning up |
| Comets |
Dirty snowballs. Ice and rock mixed together |
| 2 comet tails |
Ion tail & dust tail. Point away from the sun. |
| 2 primary reservoirs of comets |
Kuiper Belt & Oort Cloud |
| Kuiper Belt |
Flattened disk of solar system remnants out past Pluto. |
| Oort Cloud |
Spherical distribution of material even darther |
| The “Terrestrial Planets” include |
Earth, Mercury, Mars, Venus |
| Astronomers like to describe distances between planets in terms of |
AU |
| Planet that spins backwards |
Venus |
| Mercury and Venus exhibit ________________, much like our Moon. |
Craters |
| Mercury has extreme temperature differences from night to day, but is still _________than Venus, despite being closer to the Sun. |
Cooler |
| A day on Mercury takes ______ years, while undergoing _________ rotations. |
2 years 3 rotations |
| Venus is so hot because of its very strong _______________ effect. |
Greenhouse |
| Oddly, the Earth’s _______________ north is not quite at the same place as the North Pole. |
Magnetic North |
| The Earth’s ___________________ protects us from the Solar Wind. |
Magnetosphere |
| Some particles get trapped in the _________________ Belts. |
Van Allen |
| When these overflow, we see _______________. |
an Aurora |
| Craters on the Moon are made by the same sort of ________________ impacts that we find on Earth. |
Meteor |
| Largest volcano in the Solar System. |
Olympus Mons |
| While the Sun has no surface, the outer layer that we see is called the |
Photosphere |
| Chromosphere |
layer just above the photosphere. Sort of the “lower atmosphere” |
| Corona |
above the chromosphere. Sort of a hot upper atmosphere |
| Sunspots |
Dark blotches ont he surface of the sun |
| Sunspots are linked by |
Pairs of magnetic field lines |
| What causes kinks? |
the rotation of the sun drags magnetic field lines around with it |
| Number of sunspots |
varies with time. 11 year cycle |
| What happens when the sun's magnetic field prevents hot, ionized material from rising? |
Dark sunspots result |
| When does the Sun's northern magnetic pole become the southern magnetic pole? |
after 11 years |
| Solar Flares |
eruptions in the Sun's atmosphere that cause energetic particles to escape from the sun |
| Coronal mass ejection |
emits charged particles that can affect the Earth |
| How do stars shine? |
nuclear fusion |
| Nuclear fusion |
the extra mass is converted to energy according the Einsteins famous formula, E=mc2 |
| Hydrostatic Equilibrium |
Fusion keeps stars from collapsing under their own weight. Pressure from the outflowing hot gas balances the pressure of gravity |
| Stellar evolution |
big bang |
| A stars brightness is effected by |
its distance from the Earth |
| Inverse square Law |
Move 2x as far from a light and it gets 4x dimmer |
| Temperature of stars |
Color of a star is indicative of its temperature. Red- cool Blue- Hot |
| Hertzsprung-Russell (H-R) diagram |
any plot of brightness vs. color or temperature is and HR diagram |
| Percent of stars on "main sequence" |
90% |
| Percent of stars are red giants |
9% |
| Percent of stars are white dwarfs |
1% |
| Main sequence stars are also called |
dwarfs |
| Red Giants |
much bigger than the sun, coolest |
| Supergiants |
bigger and brighter then the average giants |
| White Dwarfs |
Much smaller than the sun, very hot but not very bright, remnants of dead or dying stars |
| supernova |
star blown into smithereens |
| nebula |
supernova remnant |
| Pulsars |
type of neutron star emitting regular pulses of light |
| What happens when compressed gas from stars collides? |
New stars form |
| Galactic Cannicalism |
when two unequal size galaxies collide and merge |
| Quasars |
Active galaxies |
| Most big galaxies have supermassive _______ in their centers |
black holes |
| During a merger, what happens when fuel is fed into a black hole? |
A hot disk of material that spirals into the black hole. the disk shines brighter than the galaxy itself |
| Energy source of a Quasar |
black hole surrounded by an accretion disk |
| When did the universe begin? |
about 13.7 billion years ago |
| Cosmology |
study of the origin, structure, and evolution of the universe |
| Universe |
all matter, energy, and spacetime |
| Homogeneity |
Matter is uniformly spread throughout space |
| Isotrophy |
Universe looks the same in every direction |
| cosmological principle |
any observer in any part of the universe sees the same general features |
| Olber's Paradox |
If the universe is homogeneous, isotropic, infinite, and unchanging, the entire sky should be as bright as the surface of the Sun |
| Why is it dark at night? |
The universe is homogeneous and isotropic, it must not be infinite or unchanging |
| Hubble Flow |
The universe is not unchanging, it is expanding |
| Doppler effect |
motion through space-time |
mr. charles11
