How do we know the sun rotate

Answer: One side is blue-shifted and the other side is red-shifted.

Explanation: APEX 12/31/19

From the movement of sunspots, Galileo discovered that sun rotate s on its own axis.

Explanation:

All the sunspots are traveling across the Sun's head. This movement is part of the Sun's general rotation of its axis. Observations also suggest that the Sun does not rotate like a solid body, but rotates differently because it is a gas. Actually the Sun is spinning faster at its equator than at at its poles. The Sun rotates once every 24 days at its equator, but only once every 35 days at its poles. We learn this by observing the movement of sunspots and other solar features pass through the Sun.