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29 Cards in this Set
- Front
- Back
what is astronomy?
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the study of the universe and the objects in it.
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what is the difference between a rotation and a revolution?
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a rotation is when an object spins on its axis. a revolution is when one object moves around another
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what Evidence supports the big bang theary?
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the universe is expanding
left over cosmic backround radiation evenly distributed from the big bang |
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what is dark matter and energy?
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matter that does not give off light, we can only detect it by the gravity that it emits. it fills 96% of the universe. the other 4% is suns, planets, and matter between the stars
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how do scientists know the composition of distant stars?
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each element has different spectral lines when viewed through a spetrascope
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what is the speed of light?
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in a vacuum it is about 3 million meters per second.
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what is a light year?
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the distance light travels in a year
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describe the doppler effect?
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a change in the apparent frequency of waves when either the source or the observer is in motion
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what is apparent magnatude?
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the brightness a star apears to be as seen from earth
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what is absolute magnatude?
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how bright the star would apear at 32.6 ly from earth aka the true brighness of a star
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how do stars form?
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they are "born" within a spinning nebula, the could collapses into a hot dence core and begins gathering dust and gasses. gravity pulls the materials together intil the temp. is hot enough for fusion to occur.
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how do stars produce light?
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during each step of fusion energy is released int he form of light waves
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how are stars organized?
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baced on their brigness and temperature.
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what is the order of stars for coolest to hottest?
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ROY G BIV
red yellow white blue |
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wht is the life sequence of a medium mass star?
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nebula-> average star-> forms a red giant-> planetary nebula
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what is the life sequence of a large mass star?
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nebula-> massive star-> forms a red supergiant-> super nova->neutron star or ->black hole
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what is a galaxy?
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a collection of dust gass stars and black matter held together by gravity
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how big is our solar system??
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100,000 ly
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describe and elliptical galaxy
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shaped like a football,not a lot of dust and gasses mosty older stars
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describe a spiral galaxy
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most common, contains lost of dust and hydrogen gasses. younger stars
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describe an irregular galaxy
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no particular shape, none are alike.
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describe the size ranges:
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Galaxy cluster->galaxy->golbular cluster->stars
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how do the planets move around the sun?
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in an elliptical orbit
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what are the layers of the sun?
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core->radiative zone->convective zone->photoshere->chromoshere->corona
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_ _% of the sun is _____ and ________
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99% heilum and hydrogen
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what is a solar wind?
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a stream of energy particles.
1 mill mph |
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what are the EQUNOXES?
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the biggining of spring and fall.
when the sun is directly above the equator |
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the summer solstices is______
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the longest day of the year and the first day of summer. the sun is direclty over the tropic of cancer, 23.5* NL.
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the winter solstice is______
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the shortest day of the year and the first day of winter. the sn passes over the tropic of caperacorn which is 23.5* south lataude
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