Spectral analysis can identify the elements present in a distant star because

  • A. every element has its own unique pattern of spectral lines
  • B. all stars contain the same elements
  • C. starlight is white
  • D. the star's temperature is known in advance

Explanation

The line pattern is fixed by the element's own energy levels, so it acts as a fingerprint that survives the journey across space. Helium was in fact discovered in the Sun's spectrum before it was found on Earth, which is how it got its name. Line positions also reveal motion through the Doppler shift.

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