How do we know the sun rotates?

a) both sides are red-shifted.
b) because the earth rotates.
c) both sides are blue-shifted.
d) one side is blue-shifted and the other side is red-shifted.

D because it could be dark in the UK and it could be light in the US and there would not be no other way for that to happen.

Wind causes waves to form

This type of galaxy is an approximately ellipsoidal shape and a smooth, nearly featureless image. they are the largest single star systems, in the universe and are built by the collisions of many smaller galaxies.