Astronomers find that light emitted by a particular element at one edge of the Sun has a slightly higher frequency than light from that element at the opposite edge. What do these measurements tell us about the Sun’s motion?

Answer 1

It indicates the sun rotates, so the side rotating away from us is moving more slowly (relative to us) than the side rotating towards us.

Of course, a tiny part of the shift is due to our revolving around the sun, but that doesn't count much.

Answer 2

thank you, is this related to the doppler effect

Answer 3

It is exactly the Doppler effect.

Answer 4

Thank you