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Cards In This Set
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The universe in expanding because
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Space itself is expanding carrying the galaxies (or clusters of galaxies) with it
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What is "cosmological redshift"?
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The stretching of the wavelengths of photons as the travel through expanding space
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The Hubble Classification for a very flat elliptical galaxy is
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E7
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Synchrotron radiation is produces
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Whenever electrons move in spirals in a magnetic field
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If the universe is unbounded it will
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Expand forever
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If space is flat, what is the future of the universe?
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It will barely expand forever, reaching zero expansion speed after infinite time
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What was the COBE satellite designed to measure?
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The cosmic microwave background radiation
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The observational fact the convinces astronomers that the source of energy in a typical quasar is physically very small is
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The rapid variation of the intensity of the source
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In the 1970's, it was discovered that among spiral galaxies, the wider the 21cm radio emission line is, the brighter the galaxy. What name is given to this relation?
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Tully-Fisher relation
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Edwin Hubble first showed that recessional speeds of galaxies
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Increase with increasing distance from earth
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Elliptical galaxies contain primarily what type of stars?
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Pop II, low mass, long-lived stars
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The "central engine" of an active galaxy appears to be
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A supermassive black hole at the center of an accretion disk, with jets of material being ejected perpendicular to the disk.
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This is NOT a characteristic of elliptical galaxies
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They have a disk and central bulge, but no spiral arms
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Cosmologists study
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The origin, structure, and evolution of the universe.
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In relation to the universe, isotropic means
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The expansion is the same in all directions
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