GK
THE UNIVERSE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Astronomers examine the spectra of a distant galaxy and see that it displays a red shift. What does this mean about the motion of the galaxy?
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The galaxy is not moving.
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The galaxy contains mostly red giant stars.
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The galaxy is moving towards Earth.
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The galaxy is moving away from Earth.
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Explanation:
Detailed explanation-1: -Astronomers have found that the further from us a star is, the more its light is red-shifted. This tells us that distant galaxies are moving away from us, and that the further away a galaxy is, the faster it’s moving away.
Detailed explanation-2: -For very distant galaxies, the effects of curved space causes the wavelengths of light to be increasingly red-shifted as the distance to Earth increases. This is a Doppler-like effect, but it has nothing to do with the speed of the galaxy or star, but on the c hanging geometry of space over cosmological distances.
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