Exam-style question
Try this first
Explain how redshift in astronomical spectra provides evidence for the expansion of the Universe.
Model answer
What a good answer should say
- Redshift occurs when light from an object moving away from us is stretched to longer wavelengths.
- This shift towards the red end of the spectrum indicates that galaxies are receding, supporting the theory that the Universe is expanding.
Explanation
Why this works
This answer is strong because it clearly connects the concept of redshift to the evidence for an expanding Universe, demonstrating an understanding of the Doppler effect in a cosmological context. It tests the student's ability to apply theoretical knowledge to observational evidence.
Common mistake
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