If fire needs fuel and air in order to burn, how does the sun stay afire?

Answer 1

Ordinary fire involves carbon, hydrogen, and oxygen exchanging electrons to release energy. All the carbon atoms remain carbon atoms, all the hydrogen atoms remain hydrogen atoms, and all the oxygen atoms remain oxygen atoms.

Not so in nuclear fire. In nuclear fusion, hydrogen smashes together at such high speeds that the nucleus of the atoms is reformed, creating a new atom (helium) and releasing energy. The high-strength nature of nuclear forces (much stronger than the electrical forces governing electrons) are why nuclear weapons are so much more powerful than conventional (chemical) explosives.

Answer 2

A brief explanation of how the sun is fueled:

Although there is no oxygen in space, the Sun itself is made up of elements including hydrogen, helium, carbon, oxygen, iron and many others. The most abundant element in the Sun is hydrogen and that is infact what is fueling the Sun at this point in its life.

"Burning" hydrogen is a phrase we use to describe what is happening on the Sun, but it is not like "burning" things on Earth -- "burning hydrogen" is a fancy way of saying the Sun FUSES hydrogen atoms into helium atoms. Nuclear fusion takes the particles that make up hydrogen and sticks them together to make helium (1 helium atom is made from 4 hydrogen atoms). In order to make the protons and neutrons in the helium stick together, the atom gives off tremendous energy, which makes the center of the Sun very hot and produces the light that we see here on Earth.

You can think of it this way, the Sun is very dense in its core and the atoms there are packed very close together. In addition, it is very hot and the high temperature causes the atoms to move around very quickly. The combination of high density and fast motion forces the hydrogen atoms to slam into one another quite often. When the hydrogen atoms slam together they release energy and produce helium. Once all the hydrogen is used up the Sun will start to fuse helium in the same manner, producing carbon as a by product.

You could imagine packing a bunch of people into a small room and then having them run around very quickly. They would not be able to do that without bumping into each other. The faster they move, the harder they will slam into one another. Each slamming together releases energy and within the Sun that energy is what fuels it.

Answer 3

It's an atomic fusion reaction of Deuterium (Heavy Hydrogen) that forms Helium.
No other fuel or oxygen (air) is involved.

(Normal Hydrogen ( 1proton and 1 Electron CANNOT fuse into Helium. Helium has 2 protons, 2 neutrons and 2 electrons which are supplied by Deuterium (1 proton, 1 neutron and 1 electron). When two atoms of Deuterium fuse together, THEN Helium is formed).

Answer 4

To "burn" something you oxidize it. The energy radiated from the Sun comes from it converting approx 600 million tons of hydrogen into helium every second through nuclear fusion. the electromagnetic radiation emitted by the fusion process radiates in fequencies all across the spectrum from radio waves to gama rays, which includes what we call visible light. The amount of matter converted into energy from the reaction can be calculated by the most famous equation: E=mc^2.

Edit after reading a previous answer: splitting atomic nuclei is the process of nuclear fission; what nuclear reactors do. Fusion is the process of fusing together nuclei into another element, which is what all stars do.

Answer 5

It's not a chemical combustion, the way we normally think of fire. In other words, it's not burning. It's a thermonuclear reaction, which is going on in the nuclei of the atoms, not with the electron clouds of the atoms like in an everyday chemical reaction.

Answer 6

This was the big question of 19th century cosmologists. The answer is that the sun is not 'on fire' and is not 'burning'. It's hot because of nuclear fusion reactions which do not need air. The fuel is hyrogen, which is what the sun is made of.

Answer 7

Nuclear fission, like in a nuclear power plant,can create heat in a vacuum due to the energy released when atoms are split.
The sun creates heat by nuclear fusion, that is converting hydrogen into helium under the tremendous pressures and heat created by the suns gravity.
Anytime you split an atom (fission) you release energy, and any time you fuse atoms (fusion) you release energy-E=MC2

Answer 8

Its not fire like a campfire (boy, how many times has THIS question been asked - doesn't anyone read anymore?).
The sun fuses hydrogen to helium like a huge nuclear fusion reactor. It needs nuclear fuel (hydrogen) and it has billions of tons of it.
Nuclear reactions don't need oxygen (a fire doesn't need air by the way, it just need oxygen).

Answer 9

Nuclear fusion. You don't need air for that to work. Just lots of matter tightly packed, as in the interior of the Sun.

Answer 10

It's not on fire.

Fire is oxidizing something, that is burning in the presence of oxygen. You need fuel, air, and heat for this process.

The sun is burning mainly helium in a process called fusion. Which gives off heat and radiation...