How does looking at distant galaxies allow us to look back in time ? What keeps the sun spinning ?

Question: How does looking at distant galaxies allow us to look back in time ? What keeps the sun spinning ?
- Keywords:
  distant,
  galaxy,
  spin,
  sun
Asked by bluemarshmellos to Col Op, Elie, Floris, Jenn, RocketRich on 16 Mar 2016.
- Floris Van Den Berg answered on 16 Mar 2016:
  
  When we look at distant galaxies, the light has travelled a long way, sometimes millions of years before it reachus us, this light what we see is an image of what happened millions years ago, so we look back in time.
  
  The suns keeps burning through nuclear fusion.

Question: How does looking at distant galaxies allow us to look back in time ? What keeps the sun spinning ?