When you look up at the night sky, you are looking at stars. We call them stars but they are really just suns that are very far away from us. Just like our sun, they shine on the planets that orbit them. But not all stars are like our sun. Some stars are blue, some are red. Our sun is yellow. Because they all shine differently, their light refracts differently. We can use their refraction to help us identify what these stars are made out of.