does the sun spin itself? if so how fast and how do you know?

Question: does the sun spin itself? if so how fast and how do you know?
- Keywords:
  spin,
  sun
Asked by simmy123 to Amy, Grant, Martin, Shawn, Usman on 15 Mar 2013.
- Grant Kennedy answered on 15 Mar 2013:
  
  The reason that the Sun spins is because it was spinning from the very start when it formed. It spun a bit faster after it formed and shrunk, kind of like a ballerina bringing her arms in to speed up. If goes around once every 25 days, we know that because we watch it going around. The radius is about 700,000km, so the surface is going around at about 2km/s!
  g
- Martin Archer answered on 15 Mar 2013:
  
  The Sun does spin, but because it’s made of a super hot gas called a plasma it’s a bit different to Earth. Earth spins at the same rate wherever you are because it’s solid, but the Sun actually spins at different rates depending on where you are. At the equator the Sun takes about 25 days to do a full rotation, but because Earth is moving around the Sun it looks like 26 days from here. We measure the solar rotation rate by tracking the motion of sunspots on the Sun’s surface.

Question: does the sun spin itself? if so how fast and how do you know?