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8 Cards in this Set
- Front
- Back
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What properties must a standard candle have?
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Must have a narrowly defined luminosity, so that the uncertainty in estimating its brightness is small and be bright enough to be seen at great distances
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What is a cepheid variable? What is the period/luminosity relationship?
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Stars whose luminosity varies in a characteristic way, with a rapid rise in brightness followed by a slower decline. A determination of this period can used to obtain an estimate of the star's distance.
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Tully-Fisher relation
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A relation used to determine the absloute luminosity of a spiral galaxy.
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Doppler effect
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Any motion-induced change in the observed wavelength of a wave.
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Redshift
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Motion-induced change in the wavelength of light emitted from a source moving awy from us.
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Cosmological Redshift
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The component of the redshift of an object that is due only to the Hubble flow of the universe.
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What is the Hubble Law?
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Law that relates the observed velocity of recession of a galaxy to its distance from us.
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Hubble's constant
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The constant of proportionality that gives the relation between recessional velocity and distance in Hubble's law.
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