whats igniting the sun? when will it go out?

Question

so this sun of ours has been burning for thousands of years, do you think that it was larger in size then and that it has gotten smaller over the years from burning away? is the sun in perpetual motion?

Answer 1

The Sun has been burning for Billions of years, and has exhausted about half of its fuel. Its size has not changed much, but it is getting slightly brighter. (it would take millenia for us to notice with the naked eye...). As it approaches the end of its life (another 4-5 billion years), it will expand greatly and destroy all of the inner planets, including earth. No worries, we would have been killed off by the Sun's increased output long before then (and humanity will be gone in 4 billion years, anyway.)

The ignition source is nuclear fusion, caused by tremendous gravity at the center of the sun.

Answer 2

1. Nuclear fusion is igniting the sun.
2. About 5 billion years from now, it will use up its fuel.
3. It's been burning for 5 billion years, not thousands.
4. Larger in size? No, it's been about the same. The sun's size is determined by an equilibrium between the outward pressure of the nuclear furnace and the inward pressure of gravity. So if the outward pressure has remained constant, as astronomers assume, then the sun's size has not changed.
5. It's perpetually in orbit around the galactic center.

Answer 3

Stars form when massive amounts of dust and gas (usually Hydrogen) coalesce into fantastic disk shapes that spin. As they move faster and faster, the pressure inside becomes very high and the temperature will increase. Eventually, when it's big enough, there will be so much pressure, that the atoms at the center will fuse together making a bigger atom, a few strange subatomic particles, and an insane amount of energy.

The heat of this reaction, called a fusion reaction, creates the necessary heat and pressure for other atoms to do the same, making a ginormous chain reactions of hyper intensive nucleosynthesis, making a lot of heat, particles, and heavier atoms. That is how our sun keeps on truckin'.

Of course it has gotten somewhat smaller as it continues it's exhaust of material, but eventually it will increase in size. Our Sun will burn as it's burning now for awhile, because our sun has two billion billion quintillion quintillion quintillion quintillion kilograms of junk to fuse. However, about five billion years down the line, all those heavier atoms that the sun was making will build up. Heavier atoms are much harder to fuse, but the Sun will manage it, at first.

Of course the Sun can not be in perpetual motion, you run into issues with the second law of Thermodynamics. It will end in a glorious fashion. That extra energy will force it to swell up as it continues to fuse heavier and heavier stuff. When it can no longer fuse, it will fall in and create a super hot white dwarf.

Now, you do have some time to make travel plans, because this isn't happening for a few billion years, but in summary, it's continuous atomic fusion reaction that ignite our Sun, and it will cease fusion in about 4 billion years.

Answer 4

The Sun is not burning the way a fire burns on Earth. The Sun is a huge ball of 74% hydrogen and 26%helium. It's heat and light are the results of fusion reaction taking place deep within the Sun. The surface is not burning or on fire. The Sun is believed to be middle aged as far as the life an average star goes for it's size and will not change or run out of fuel for billions of years. Just as the Earth goes around the Sun, the Sun also is moving through space and our whole solar system orbits around the center or our gallaxy The Milky Way. It takes 250 million years for our Sun and us to orbit the gallaxy.

Answer 5

Actually the Sun is not "burning", it is fusing. The core of the Sun is hot enough and the pressure is high enough that hydrogen atoms are being fused to form helium. This releases a small amount of energy, part of which we "see". The size of the Sun has not changed much. There is enough hydrogen left to keep this hydrogen fusion reaction going for some 5 billion years, then the Sun will begin fusing the helium.

Answer 6

perpetual motion? you mean constantly moving? yes, it is. It used to be larger in volume it has gotten smaller not so much because of lost mass but because of light elements fusing into heavier ones which take up less space (which answers your first question, what is it burning. It is burning hydrogen mostly). It doesn't "burn away" like a fire does. Some of the outer layers are pushed out by pressure waves, also the solar wind carries a small amount of mass away, and a small amount is also lost by energy radiation. But by far the majority of the sun's mass stays in the sun.

Answer 7

The sun functions by fusing some million tons of hydrogen into helium every second. Since the helium weighs less than the hydrogen, energy is produced according to E = mc^2. Since the sun is very large, it will take billions of years for this process to come to a stop. When that happens, the sun will turn into a red giant star and eat the earth.

Answer 8

The sun is made mostly of helium and hydrogen. The heat is making hydrogen fuse into helium, which makes more heat, so it's like a chain reaction. It's been going on for billions of years and there's enough hydrogen to keep it going for billions more. The number I've heard is five billion more years.

As it burns it grows, not shrinks. Dying stars get bigger and bigger. Eventually the sun will grow to engulf the earth! I'm guessing life will have long since ceased to exist on earth. But don't take my word for it. Stick around and see!

Answer 9

the sun has not been burning for 4.5 to 5 billion years like all of you say. It has actually been proven that the sun has been burning for about 12 billion years. Scientists know this because remains of the asteroid that killed the dinosaurs and left the crater in the Gulf Of Mexico were found on the sun.

Answer 10

The hydrogen of the sun is not 'burning' it is fusing into helium.
The sun is actually a gigantic exploding hydrogen bomb. The large gravity keeps it all together. It will continue for another 5 billion years.

Note: Helium is not lighter than hydrogen. It is lighter than the two hydrogen atoms needed to create it