Years ago, scientists believed that the reason of the sun shone was that it was burning. But the sun has been hot for hundreds of millions of years, and nothing could remain burning for that long.
Nowadays scientists believe that the heat of the sun is the result of a process similar what takes place in an atom bomb. The sun changes matter into energy. Twenty eight grams of matter could produce enough energy to melt more than a million tones of rock. So if science is right, the sun keep shinning because it is constantly changing matter in to energy.
More to the point....the sun fuses hydrogen atoms into helium atoms and the process releases much energy.
i think all the bunnies and kittens playing together and every sister and brother getting along keeps the sun shining :3