ExploraTour - How to Build a Star
However, the sun is slowly changing. Its starting to have more and more helium in it. Helium is the gas that makes balloons float in the air.
If you look at the sky on a clear night, what do you see? The whole sky is covered with stars. Each of these stars is changing its mass into energy. So why don't we see things getting smaller as they change their mass into energy here on Earth?