The Sun is the Power House for the entire Solar System. It is a fairly typical star that is not burning, but is fusing together Hydrogen to form Helium. In so doing, it releases energy in vast quantities. It is one of 150 billion stars in our galaxy, The Milky Way. Despite consuming 5 million tonnes of Hydrogen every second , there is enough material left for it to exist for another 5 billion years .
Heavier stars have much shorter lifetimes, since their greater gravity increases the rate of fusion.
This also makes them hotter and brighter than our Sun, whose surface temperature is about 6000K. More on stars . Fusion Perfected On Earth , humans use Nuclear Fission to produce energy for some of our electricity supply. This is somewhat inefficient, and produces very dangerous nuclear waste. Fusion of Hydrogen into Helium In studying the Sun, we humans have learned how to produce energy from Nuclear Fusion. This century, it may become our main source of energy.