This is nuclear fusion and it produces incredible energy. However, as its hydrogen reserves dwindle that process will speed-up, making the Sun shrink yet shine more brightly. Earth will be scolded and become bone-dry. In about 5.5 billion years the Sun will run out of hydrogen and begin expanding as it burns helium.

Will the Sun eventually burn itself out?

For about a billion years, the sun will burn as a red giant. Then, the hydrogen in that outer core will deplete, leaving an abundance of helium. ... Astronomers estimate that the sun has about 7 billion to 8 billion years left before it sputters out and dies.

What keeps the Sun from burning out?

The sun does not run out of oxygen for the simple fact that it does not use oxygen to burn. The burning of the sun is not chemical combustion. It is nuclear fusion. ... At the same time, hydrogen atoms in the fuel bond with oxygen atoms to make water molecules.