For each star, determine how its light would be shifted. Not all choices may be used, and some may be used more than once.

A. A blue giant moving away from Earth at 39.9 km/s
B. A yellow dwarf moving transversely at 16.3 km/s
C. A red giant moving towards Earth at 22.7 km/s
D. A blue dwarf moving away from Earth at 37.9 km/s
E. A blue giant moving transversely at 30.1 km/s

Light from stars moving away from Earth will show a redshift, while those moving towards us will show a blueshift. Transverse movement doesn't produce any shifts in the light spectrum. Detecting these shifts is possible with the use of large telescopes and does not depend on the star's distance.

Explanation:

The question focuses on the Doppler effect on light from stars moving relative to the Earth. Light from a star exhibits a redshift when it is moving away from the Earth, shifting to longer wavelengths, and a blueshift when moving towards the Earth, shifting to shorter wavelengths. Transverse motion, although it results in proper motion, doesn't cause redshift or blueshift. For the stars listed:

Using the Doppler effect, you can detect the motion of stars and even the presence of planets. The effect is observed as a spectral change and does not depend on the distance to the star, provided the star is bright enough to have a spectrum resolved by a large telescope.