fire needs 3 things to exist,fuel,oxygen and heat. so if space is a vacuum how come the sun keeps burning?

Answer 1

Nuclear fusion is not a fire; it's more like an explosion.

The high enough tempatures in a stars core due to gravitational contracting enable it to generate energy (on all wavelengths) through the process of Nuclear Fusion; like others have said, the first one is the proton-proton reaction.

Through the process of Nuclear fusion, hydrogen atoms are stuck together to produce helium.
4H -> 1He/
Anyways, it releases a free neutron that immediately decays, a lot of neutrinos, and a whole lotta energy.

And, no.
The atom bomb uses nuclear fission, not fusion. Fission is the opposite of fusion.
Fission happens when a free neutron is fired into the core of the atom, breaking it to form two other atoms (I think), a free neutron, and energy. This starts a chain reaction until all the mass (or most of it) is broken down and the energy released in an explosion.
Nuclear fusion is more efficient in terms of energy production than nuclear fission, however the most efficient by far is anti-matter/matter collision.
An antimatter/matter collision causes both particles to immediately annihalate each other, releasing all the energy stored up in the particles. By the end, no particles are left.
General Relativity and Quantum Mechanics teach us that particles are just balls of energy.
This is explained by the famous equation:
E= MC^2.
E = Energy
M = Mass
C = Speed of light constant.
Hope this helps. :)

Adding stuff.
Yes, stars like the sun, having used up all the hydrogen (or most of it) undergo the CNO cycle.

More massive stars (over 1 solar mass) live shorter lifetimes, but produce most of the elements up to iron.

The most massive stars, when supernovaeing, generate so much heat that they even fuse iron.
That's how we get the elements.

In the Big Bang, the only elements that were created were hydrogen, some helium, and a very tiny bit of lithium.

After 380,000 so years, the first stars, the hypothetical "Population III" stars, with masses greater than 100+ solar masses, started to get to work and start making the other elements.
That's how stars shine.

Answer 2

The Sun is not really burning. It is extremely hot though. It puts off heat/energy through the nuclear fusion of hydrogen atoms, the first and most abundant element in the universe. Although you don't see often that you know of, heat/energy doesn't have to come from fire. Many chemical reactions also put off heat. The Sun is so hot that it's not even a gas/air but an even more chaotic and expanded state of matter known as plasma.

Answer 3

3 Things A Fire Needs

Answer 4

People really puzzled over this question until we finally discovered that the sun couldn't be powered by ordinary fire. If you work out the amount of power it puts out and figure out how long it take to burn up all its mass in an ordinary fire, it wouldn't last long at all.

Nuclear fusion puts out an astounding amount of energy for the amount of fuel it uses. That's the source of the sun's power. You might read the word "burn" when folks talk about the sun's mechanism, but they don't mean it literally.

Answer 5

The surface composition of the Sun consists of hydrogen (about 74% of its mass, or 92% of its volume), helium (about 24-25% of mass,[1] 7% of volume), and trace quantities of other elements, including Fe, Ni, O, Si, S, Mg, C, Ne, Ca, Cr.[2] The Sun has a spectral class of G2V. G2 implies that it has a surface temperature of approximately 5,780 K, giving it a white color which, because of atmospheric scattering, appears yellow as seen from the surface of the Earth. This is a subtractive effect, as the preferential scattering of blue photons (causing the sky color) removes enough blue light to leave a residual reddishness that is perceived as yellow. (When low enough in the sky, the Sun appears orange or red, due to this scattering.)

Its spectrum contains lines of ionized and neutral metals as well as very weak hydrogen lines. The V (Roman five) suffix indicates that the Sun, like most stars, is a main sequence star. This means that it generates its energy by nuclear fusion of hydrogen nuclei into helium and is in a state of hydrostatic equilibrium, neither contracting nor expanding over time. There are more than 100 million G2 class stars in our galaxy. The Sun is brighter than 85% of the stars in the galaxy, most of which are red dwarfs.[3]

Answer 6

The Sun is not burning fuel in a chemical (inter electrons) reaction as you have indicated in your question. In fact, the Sun is liberating the energy trapped in the nuclei of atoms in a process known as fusion.

The Sun is a giant gas ball, of about 71 % hydrogen and 27 % helium along with some 'metals' (astronomers call all other elements – ‘metals’), with a mass of 1.989 x 10^30 kg and a radius of 6.8 x 10^8 m and its surface temperature is 5730 K. The surface gravitational acceleration for the Sun is over 200 m/s/s. Hence, the Sun has a very strong gravitational field. This means that, the gravity of the Sun causes its core (about 25% of the inner radius) to be extremely dense (150 times the density of water) and under high pressure. This high pressure forces the atomic nuclei closer to each other. Those nuclei that approach very closely are ‘snapped’ together by the strong nuclear force (this force, at a close range is stronger than the electro-static repulsion between the nuclei's constituent protons) in a process known as fusion. This process also releases binding energy and nuclear particles. We see this released energy as Sun light. The energy is of course nuclear energy released by the fusion processes at the core.

Small stars 'burn' proton-proton fusion, in their cores, to generate helium and energy and have core temperature greater than 10^6 K. Hotter and slightly, bigger main sequence stars, such as our Sun, have a more complex fusion cycle at their cores’, known as CNO cycles (Carbon, Nitrogen, Oxygen) and core temperatures greater than 10^7 K. This answer format does not really permit me to set this cycle out - I suggest that you look it up in (say) Wikipedia. Finally, very large stars (greater than 2 solar masses) have surface temperatures over 10^5 K and core temperatures greater than 10^8 K. These massive stars burn through their main sequence life's in millions of years (our Sun will stay in the main sequence of core fusion for about 9 billion years and has so far lasted 4.5 billion years).

Hence, to answer your question - the Sun is not undergoing a chemical fire its core is liberating energy in a nuclear fusion storm! We see the light of this fusion process as Sun shine.

Answer 7

Space isnt a vacuum.
It nearly is, but it has millions of particles that are just really far apart from each other.
Plus, there's the whole nuclear fusion thing. Fusion reactions power the stars and produce all but the lightest elements in a process called nucleosynthesis.

Answer 8

It's not on fire. It's fusing hydrogen into helium. You know the bomb tests over Bikini Atoll? The sun is doing that, millions of times a second. No oxygen required.

Answer 9

The sun is not burning. Its heat is generated by the release of extra binding energy from the fusion and disintegration of the atoms making it up.

Answer 10

the sun isn't a vacuum! any heat that gets to us travels by radiation