How does the sun not burn out? --- Dennis, Indio, Calif.
Marshall Brain Answered:
The sun is a gigantic fusion reactor. It fuses atoms together to generate heat and light. Each time atoms combine, a tiny bit of mass turns directly into energy.
How much mass does the sun lose each second? Here's the answer:
The answer? "The Sun is using losing 4 billion kilograms of mass a second." That seems like a gigantic loss of mass - 4 billion kilograms literally disappears every second!
But the sun is stunningly immense, and at the sun's scale, 4 billion kilograms is nothing. The sun can burn fuel at that rate for millions of years. On a percentage basis, it will have very little effect.
If you want to know more about the sun, this video provides details:
See also: How the sun works