Term
| three main types of galaxies |
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Definition
| spiral galaxies, elliptical galaxies, and irregular galaxies |
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Term
| spiral galaxies classifications |
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Definition
flat white disks with yellowish bulges at centers. cool gas and dust
have disk, bulge, and halo |
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Term
| elliptical galaxies classifications |
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Definition
redder, rounder, often contain very hot ionized gas
bulge and halo (no disk) |
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Term
| irregular galaxies classifications |
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Definition
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Term
| Groups and clusters of stars |
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Definition
| spiral galaxies tend to congregate in small groups while elliptical galaxies are primarily found in large clusters |
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Term
| How to measure distance of galaxies |
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Definition
| measuring the apparent brightness of an object whose luminosity we already know and applying the inverse square law for light |
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Term
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Definition
| most useful measuring the distances to galaxies that have a period-luminosity relation. 30 day intervals |
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Term
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Definition
expresses the idea that more distant galaxies move away from us faster with a
v=Ho x d |
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Term
| what Does a galaxies redshift tell us? |
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Definition
| how fast it is moving away from us, and the relationship between redraft and distance shows that the universe is expanding. |
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Term
| age of the universe? and how we know |
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Definition
| bubble's law, the rate at which the universe expands tell us it is 14 billion years old |
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Term
| What do protogalactic clouds form and how? |
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Definition
| elliptical galaxies from spinning slowly or from dense clouds |
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Term
| What can form from a collision between two spiral galaxies? |
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Definition
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Term
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Definition
| the most luminous active galactic nuclei. a trillion times the luminosity of the sun. |
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Term
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Definition
| a galaxies that emits unusually strong radio waves |
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Term
| what is a jet in relation to a radio galaxy? |
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Definition
| the jet propels particles moving at nearly the speed of light. |
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Term
| what is the power source of a quasar? |
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Definition
| matter falling into supermassive black holes. |
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