Question: Why does the sun not run out of oxygen as it burns???

Monique Henson answered on 13 Nov 2015:

The Sun doesn’t need oxygen to burn, because it burns in a different way to the fires we’re used to. When we burn something on Earth, we usually use heat to start a chemical reaction between the fuel and oxygen in the air. The Sun doesn’t do this. Instead, the Sun fuses together elements, which gives out energy that we see as heat and light.

What do I mean by fuse? Fusing together elements means they take two elements and combines them together to make another element. This process is called nuclear fusion. In the Sun, bits of hydrogen are fused together to make helium. It’s called nuclear fusion because it’s the nuclei of the atoms that are being combined.