Exam-style question
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How does the radial velocity method provide evidence for orbiting planets?.
- A.By measuring the light curve of the star
- B.By observing the Doppler shift in the star's spectrum
- C.By analyzing the star's luminosity
- D.By detecting changes in the star's temperature
Model answer
What a good answer should say
- By observing the Doppler shift in the star's spectrum
Explanation
Why this works
The evidence shows that the radial velocity method relies on the Doppler effect, where the spectral lines of a star shift due to its motion caused by an orbiting planet. This shift indicates the planet's gravitational pull on the star, implying that the star is moving in response to the planet's orbit.
Thus, the correct answer is the observation of the Doppler shift in the star's spectrum.
Common mistake
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