Exam-style question
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Why is redshift an important factor in cosmology?.
- A.It helps determine the temperature of celestial bodies.
- B.It provides evidence for the expansion of the universe.
- C.It indicates the chemical composition of stars.
- D.It measures the gravitational pull of galaxies.
Model answer
What a good answer should say
- It provides evidence for the expansion of the universe.
Explanation
Why this works
The cause of redshift is the movement of galaxies and quasars away from us due to the expansion of the universe. The mechanism involves the Doppler effect, which stretches the wavelengths of light emitted from these objects.
The effect is that we observe a shift towards the red end of the spectrum, leading to the consequence that redshift serves as critical evidence supporting the theory of an expanding universe.
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