Why doesn't the Sun just burn up?
956140
If the sun produced its energy by burning(like a wood fire, chemically changing atoms or molecules to other types of molecules by transferring or shifting pair bonds of small outer atom particles called electrons), the sun would indeed "burn up". In exothermic(producing heat) chemical reactions only these very light electrons give up energy. However, the sun produces its energy by the much more powerful & efficient nuclear fusion(nuclear bombs) process(hydrogen atoms are slammed together to form helium). In the sun 700 million TONS of hydrogen produces 695 million TONS of helium PER SECOND. The excess 5 million TONS PER SECOND of hydrogen-helium material is converted to pure radiant energy by Einstein's famous equation:\nE=MCsquared =M times C times C; \nwhere E= energy,\nM=mass,\nC =the speed of light=984million feet per second.\n\nAs you can see, energy is very very much when 5 million TONS OF MASS is multiplied by the speed of light(almost 1 billion feet per second), not just once, but TWICE. That is why a nuclear fusion bomb is millions of times more powerful than a chemical bomb. But the sun's energy per second isn't just one nuclear bomb...it is the very same energy as 10 BILLION NUCLEAR BOMBS PER SECOND. You may get an inkling of an idea how much power this is, if you imagine 1 square mile of terrain on the earth. In that square mile imagine 50 nuclear bombs blowing up...then one second later, 50 more nuclear bombs...then one second later, 50 more nuclear bombs...& on & on & on & on. However, that is just in one square mile on the earth. Now image that EVERY SQUARE MILE ALL OVER THE EARTH, FROM THE EQUATOR TO THE NORTH & SOUTH POLES ALSO HAVE 50 NUCLEAR BOMBS PER SECOND BLOWING UP. \n\nThat is the power of the sun.\n\nHowever, you say....fusing 700 million tons hydrogen per second must still burn the sun up in short order.\n\nBut the sun is huge...108 times the diameter & 300, 000 times the mass of the earth...for a grand total of 2200 million million million million tons of mostly hydrogen fuel. At its present rate, it would take 3.1 million million million seconds or 100 billion years to fuse its hydrogen. Towards the end of the sun's life, the sun will fuse quicker. But still the sun will fuse for 5 billion more years.
592132
There's no oxygen in space but we all breathe. The sun has enough gravity to keep the oxygen inside it just like Earth but even more so. However this oxygen isn't for burning like we would burn wood. It is part of the cycle of nuclear reactions going on in the sun. The gravity of the sun is large enough to keep the mass of gas concentrated enough to be able to sustain such nuclear reactions.
1054994
The Sun won't. The Sun is not large enough to become a super nova.
170430
I think - not sure just think- the sun is much bigger?!!!!\n\nand it is made of gas, helium! \nandddd it's so hot!
981269
It's from radioctivity and friction.  The gas giants also create more heat than they recieve from the sun.  The sun is nowhere the near the only source of energy in the solar system.
319086
First, our sun has a long time to go before it could possibly become a supernova, not for billions and billions of years, so don't worry about it, if you were worrying. OK?\n\nNow, the way a star burns is by fusion, which is building up heavier elements by fusing atoms of lighter elements together. The typical start starts out as hydrogen, and it fuses the hydrogens together into helium. \n\nWhat happens when a star runs out of hydrogen? It starts fusing the heliums together into heavier elements. In order to begin this process, the star has to contract, to squeeze everything together to make the core temperature hotter. \n\nNotice that when the star began to run out of hydrogen, it cooled off a little. So the temperature of the star fluctuates. Its size fluctuates too, since the heat energy partly counteracts the gravity that holds it together.\n\nSo, the star cools off a little, it contracts, and we call this a pulsating or variable star. (This is somewhat of an oversimplification; there are different types of variable stars. But I am ignoring them for purposes of this illustration.) Then the star begins fusing helium, and heats up again. The star expands. \n\nThe outer surface of the star explodes away in what we call a nova-- not a supernova, yet. Some of the gas rushes away and may form what is called a nebula, a cloud. some of thee nebulas give off pretty colors, because, just like a neon sign, the gas in them is excited by the energy of the star and glows.\n\nSo, after repeated cycles of this, and bazillions of years, the star is exhausted. When the star gets iron in its core, there is no turning back. You can't fuse iron into anything. \n\nBut, you say, what about those elements that are heavier than iron, like gold and mercury and uranium? Ah, I'm so glad you asked about that. That is where the supernova comes in. \n\nA supernova is the death of a star. A nova flares up and puts out lots of energy, but the supernova puts out as much energy as the star might have put out over its entire lifetime! The last time there was a supernova in our galaxy (the Crab Nebula was formed) in 1054 AD. The Chinese were the only ones whe were doing much astronomical observation then. \n\nBut it was visible in broad daylight! From LIGHT YEARS away!\n\nWhat happens is this: the star begins to contract one final time. Most of the star blows away, making a really, really impressive nebula. All the elements that were built up in the final explosion-- all the heavy elements beyond iron-- get flung out into space, where they might meet with other elements and form planets and things.\n\nWhat happens to the rest of the star? One of three things, depending on how big it is. If it is little, it may form a white dwarf, a little star that is not so big but is now mostly hydrogen and helium and will last a long time. I think they are supposed to expand into red giants when they are about to burn out, but I don't remember for sure. \n\nIf the star is medium sized, it may become a neutron star. It is no longer buring with fusion like a regular star. The nuclear particles in its core are squeezed together so that protons and electrons have lost their identities and everything is neutrons. This is as solid and dense as matter can get, neutronium. It has an incredibly strong magnetic field, bazillions of times anything on earth.\n\nThe star's axis of rotation may not line up with the magnetic poles (just the way Earth's magnetic poles are not right at the true north and true south poles.) If this hapens, and the magnetic poles are pointed in the right direction, then every time it points our way, we see a little 'flash' of magnetic energy, and we call these 'pulsars'. The first time anybody detected them, they thought they were radio signals from people in space, because they were so regularly-spaced. It is a good thing there are no pulsars near Earth, because the flashes of intense magnetic fields would fry us lik
55579
The sun is a giant ball of plasma constantly fusing hydrogen into helium.  It is not 'on fire', so to speak, so the lack of oxygen and the coldness of space don't effect it like a match or something.
1185197
Our sun will not explode. It will eventually burn out in about est. 5 billion years. Then, for the next several million years it will swell to a red giant which will possibly engulf the Earth and quite possibly Mars. Then eventually the remainder will be pushed off into space and it will shrink to a white dwarf.
430311
Why don't we just fly the planet into the sun?
1097315
Neither of those, it never sets because it doesnt move through space.  The Earth turns, so it appears that the sun is setting.
619024
sun has huge amt of hydrogen atom which under the high temp. undergo nuclear fussion reaction to produce helium ion with emission of huge amount of light & heat......so becoz of this light it always shine...& bcoz of that heat the nuclear reaction keep to continue......
748786
Well the sun is forever burning,I don't think it would cool down at any point in time.\nI think thats how it is I'm not really sure,ether way they'll burn to a crisp.\nFried monkey!Thats a new one.lol
99768
Sort of!  As the sun slowly runs out of (mostly hydrogen) fuel, it will expand into a red giant and it's radius will be greater than the current position of the Earth.  However, the Earth's orbit is currently projected to move farther out while this happens so our planet will not actually be engulfed by the sun.  It will, however, experience a very large temperature increase.
300263
Our sun began forming within an immense interstellar cloud of drifting gas and dust. Inside this cloud (called a 'nebula') were regions of relatively high density where gravity began drawing together bits and pieces of the gas and dust. Over several million years, this spherical region became denser and denser which caused its central temperature to rise. Finally, some 4.5-billion years ago, the temperature was hot enough to start nuclear fusion. Our sun was born.\n\nGod should be spelled B-I-G B-A-N-G\nPBrax@netscape.com
865349
Energy in the form of photons is generated in the sun's core. Photons like to take off at the speed of light, so they do. But they move only 1micron before running into(being absorbed by) a gas molecule. That's because the gas atoms at the center of the sun has a pressure of 250 billion times the earth atmosphere's sea level pressure. That is why gas atoms are so hard for photons to miss. But the gas atom gets so excited with the extra energy it carries from that hot photon that it lets go of another photon, that promptly runs into another gas atom. This emitting & absorption occurs 100 million trillion times PER YEAR.  You'd think all this elbowing going on that it would get to the sun's surface fairly quickly. But this radiative process takes from 30,000 to 200,000 years to make it only about 55% of the way to the sun's surface. But once it makes it to this higher convective layer of the sun(like the earth atmosphere's lower convective atmosphere), then the energy is transported fairly quickly to the sun's surface.
390316
The sun is a star. When it becomes a red giant the earth will be vaporized. thats a few billion years off but it will happen. So yes it does.
376592
The sun is in a state of happy equilibrium.\n\nThere are two main forces acting on the sun....gravity and entropy.\n\nThe sun has A LOT of mass.  With all this mass, the sun has a pretty strong gravitational field, so all this mass is pulling on itself and trying to force it to fall toward the center.  In other words, the sun's own weight is trying to collapse it.  The more the sun shrinks and collapses, the more it heats up and the pressure inside increase (as would be expected).\nThe more the sun heats up and the pressure rises, the more it wants to "blow itself apart".  After a certain point, the pressure and heat at the core is high enough for nuclear fusion to take place.  Nuclear fusion releases a lot of energy...so much energy, it is capeable of hold the sun up under its own weight.\n\nAt this point in the sun's life, the forces of gravity trying to pull the sun together and the energy released by nuclear fusion acting to hold the sun up and blow it apart of pretty much balanced.  If one force were to get the upperhand, the other force would work to balance it out.  If the sun were to shrink a little, the rate of nuclear fusion would increase to compensate.  If nuclear fusion increases, the the sun would expand, cool, and nuclear fusion would slow, allowing gravity to pull it back together.\n\nAs the sun runs out of Hydrogen to fuse, the sun will have to fuse heaveier and heavier elements with increaingly less yeild.  In the end however, our sun will expand to become a Red Giant before blowing off a lot of material and become a white dwarf star.