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define cosmolgy or astronomy
the study of the universe
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what dose human experience refer to in the universe
it includes all known matter,energy,time, and space
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what % of the universe is believed to be space
99%
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how do we measure space
a light year
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define light year and its speeds
is the distaces light travels at a speed of (186,000 miles/sec or 300,000 km/sec) in one year
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how many miles is a light year
5.8 trillion miles
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define doppler effect
refers to the change in radiation emitted from an object as it moves( towards or away)
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what color and length will light be if it is moveing towards you
blue and short
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what color and length will light be if it is moveing away
red and long
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if light has sound and is moveing towards you what sound and length will it be
short and have a very high pitch
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if light has sound and it is moveing away what sound and lenght will it be
long and a very low pitch
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define hubbles law and what year it was
1929- states that the galaxies are recedine at a rate that is proportional to their distance
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if a star or galaxy is faint or dim what can you say about it
faraway,fast,large,red shift
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if a star or galaxy is bright what can you say about it
close,slow,small,red shift
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define background radiation
is a form of energy associated w/ blasts or explosions and is observed at the outermost limits of the universe
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define big bang theory
a concept that our universe originated from an immensly hot dense source that is the site of a cataclysmic explosion 14-15b billion years ago
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define open universe
expand forever
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define big crunch
galaxy wouls stop and collaspe in on itself
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define critical density
1 atom per cubic meter to make big crunch
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do we have enough critical density to make big crunch
no
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our known theory of the universe is it big crunch or open universe
open universe
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define dark matter
is a form of matter that dose not emit or reflect any know form of radiation
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dark matter is part of what theory
big crunch
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E=mc2
- Energy
- Mass
- C= Speed of light
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define a nebula
concentrations of interstellur matter (there are 3)
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what is a dark nebula
- interstellur=IN
- IN matter- very dense clouds of hydrogen gas and dust located far from a source of light postioned between earth and a bright region of space
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what is a reflection nebula
IN matter very dense clouds of hydrogen gas and dust having a significate source of light will bend this light back and appear as a source of light
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what is an emmission nebula
IN matter low density hydrogen gas under low pressure will absorb UV radiaition and transmitte the radiation as visible light
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what is the process fo taking raditation you cant see and transmitting it as visible light
fluroescence
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define incandescence
a substance is heated to the point it becomes hot enough to radiate visible light
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define galaxy
contraction of stars (billions)
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how is a galaxy named and why
by symmerty-shape
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define irregular galaxy
mostly hygrogen gas w/ a significate amount of young stars having little or no symmerty (rarest)
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defien elliptical galaxy
most abandant -mostly old mature stars with little hydrogen gas- having a spherical to oval shape
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milky way is what type of galaxy
sprial
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define barred spiral galaxy
 stars in arm rotate faster than the stars in the core giving a rigid solid shape a bar shape
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define spiral galaxy
a centeral core made up of relativly mature stars -arms are made up of relativly young stars and hydrogen gas extends from the core. stars in the arm rotate slower than the stars in the core giving it a pinnwheel shape
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is the milky way one of the biggest galaxies having billions of stars
yes
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how many light years is the milky way galaxy from one end to the other and at its core (on its side)
- 100,000 light years
- 10,000 at the core
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milky way has how many major arms
3
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where are we located
2/3 from the core out in an arm
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what is H-R star diagram
it plots star brightness blue being high- yellow being middle-red being low
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what can you say about a blue star
bright has high or hot temps
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what can you say about a yellow star
it has an average temp and brightness
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what can you say about a red star
it is dim and has low or cool temps
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whats % of a stars life is spent in main sequence(being in the middle)
90%
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define luminosity and magnatude
refers to the brightness of a star
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if you plot a star for its temps and brightness what are they found mostly to be
main sequence stars
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what is the lifespan of a red-cool star
100's of billions of years
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what is the lifespan of a blue-hot star
few million years
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what is the lifespan of a yellow average temp star
5-15 billion years
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