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| We live ___ of an ___ galaxy |
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Definition
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| we can use the cepheid variable stars to get distances to nearby galaxies because.. |
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Definition
| their intrinsic luminosity is proportinoal to their variabiility period (londer the period higher the luminosity) |
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| RR lyrae variable stars are used to measure Disstance to distant objects in our galaxy becuase.. |
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Definition
| all RR lyrae stars have the same average intrinsic luminosity |
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Term
| mass of our galaxy can be most accurately dtermined from |
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Definition
| the disk rotation velocity at large distances from the galactic center |
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| we can tell that "dark matter"makes up most of the mass in our galaxy from.. |
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Definition
| the flat (constant rotation curve of the gas in the disk |
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Term
| Spiral disks are___ indicating that star formatin is____ |
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Definition
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| Sprial bulge are ___ indicating the star formation has___ |
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Definition
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Term
| The bulge of a spiral galaxy is __ the disk of the galazy |
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Definition
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Term
| One common cause of spirals in the gaseous disks of galaxies is |
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Term
| the most important thing that allows us to directly determine how the univers has evolved is__ |
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Definition
| the finite speed of light |
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Term
| when we observe the most distant galazies, they appear to us as |
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Definition
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| how do we know the univers is expanding? |
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Definition
| galaxies are movie away from us, the farther the faster |
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Term
| The 3 K background cosmic microwave background was casued by ... |
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Definition
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| The hubble law says that more distant a galaxy is from us the __- it is moving |
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Definition
| more quickly ... away from us |
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Term
| The cmbr allows us to determine |
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Definition
| how we move with respect to the universe |
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Term
| what is causeing the expansion of the universe to accelerate? |
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Definition
| were not sure but we call it Dark Energy |
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Term
| hwo has the big bang theory been modified to account for the fact that most distant galaxies on opposite side of the universe and beyond (and casual contact now) are so physicically and statistically similar? |
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Definition
| universe started off with and exponential "inflationary" expansion |
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Term
| we know that dark matter cannot be made of of "normal matterlike us becuase |
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Definition
| otherwise the relative porportion of the lightest elements made early in the big bang would be very different than they are |
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Term
| if 2 glalaxies collide.... |
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Definition
| there will be hardly any collisions between the stars in the galaxies |
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Term
| the most massive stars have a main sequence lifetimes which are ___ than the time it takes for the sun to go arund the galaxy |
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Definition
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Term
| what "standard candle" recently allowed astronomers to determine distance to very distant galaxies and discover that the expansion of the univere is expanding? |
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Definition
| exploding white dwarf supernovae |
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Term
| planets have been found _____ ___ ______ and intelligent life has been found___ |
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Definition
| around many stars ..... ONLY on earth |
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Term
| untill recent planetary discoveries with the kepler sattelite most planets found outside our solar system were: |
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Definition
| much more massive than earth but much closer to their stars than jupiter is from our sun |
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