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| Earlier astronomers thought that distant galaxies were objects within our own galaxy that were spinning gas clouds that they referred to as ________________. |
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| The two quantities Edwin Hubble plot against each other to discover the expansion of the Universe were _____________ and ____________. |
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| velocity|distance, distance|velocity |
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| A lenticular galaxy differ from a normal spiral galaxy in that it has no ___________ in its disk. |
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| spiral arms|spiral structure |
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| A lenticular galaxy is another name for an elongated elliptical galaxy. |
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| White-dwarf supernovae are good standard candles for distance measurements for all the following reasons except which? |
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| C. White-dwarf supernovae occur only among young and extremely bright stars. |
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| Based on counting the number of galaxies in a small patch of the sky and multiplying by the number of such patches needed to cover the entire sky, the total number of galaxies in the observable universe is estimated to be approximately |
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| Which types of galaxies have a clearly defined disk component? |
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| Recall that Hubble's law is written v = H0d, where v is the recession velocity of a galaxy located a distance d away from us, and H0 is Hubble's constant. Suppose H0 = 65 km/s/Mpc. How fast would a galaxy located 500 megaparsecs distant be receding from us? |
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| Dr. X believes that the Hubble constant is Ho = 55 km/s/Mpc. Dr. Y believes it is Ho = 80 km/s/Mpc. Which statement below automatically follows? |
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| Dr. X believes that the Andromeda Galaxy (a member of our Local Group) is moving away from us at a slower speed than Dr. Y believes. |
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| Elliptical galaxies are more likely to be found in clusters than are spiral galaxies. |
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