You Asked:
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:

How much fuel does the sun burn per second

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