If the sun is supposedly burning then what is it burning?

Gnomon

The sun isn't burning in the normal sense of the word. It is undergoing a nuclear fusion reaction, in which hydrogen combines to make helium. This is the same reaction as in a hydrogen bomb. Jul 26 06, 6:22 AM

romeomikegolf

Mainly hydrogen. http://www.enchantedlearning.com/subjects/astronomy/sun/ Jul 26 06, 6:22 AM

Arpeggionist

I thought the H-bomb was the opposite process of nuclear fission (i.e. splitting helium atoms into hydrogen). Jul 26 06, 6:31 AM

Gnomon

The original "atom bombs", the ones dropped on Japan during the 2nd World War, used fission, breaking Uranium up into smaller elements. The hydrogen bomb uses fusion, combining two "heavy Hydrogens" into a Helium. So does the sun. Jul 26 06, 6:38 AM

zbeckabee

The Sun is basically a thermonuclear bomb with a built-in thermostat. Just as in a hydrogen bomb, hydrogen atoms are fusing together to make helium atoms and this nuclear reaction produces heat (along with the light that we see). If the reactions go on too fast, the Sun expands slightly (just like a balloon expands when you heat up the air in it). This slows down the reactions and then the Sun cools and contracts. If it contracts too much, the nuclear reactions speed up, and then the Sun heats up and expands again. So the Sun stays at the same temperature, burning its nuclear fuel at a steady rate. At the rate it is going, we have about 4 billion years left until the Sun burns out. http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961107a2.html Jul 26 06, 9:27 AM