When you see a falling star,and it comes down toward earth,is there anything left of it,or does it burn up?
488119
depends on how big it is when it enters the atmosphere
1102869
A partial answer is that nothing is really stable in space; everything is moving. Some stars are moving toward us, others away. We don't notice these movements because of the large distances involved, but you would be able to if you could live long enough. For example, within 100,000 years, the Big Dipper will no longer look like a dipper, because the stars will be in different positions in the sky.\n\nAnother partial answer is that there is no objective "up" or "down" in space. Those are concepts that we have developed because of our own experience on Earth. For example, if you were to point straight up, and a person on the other side of the world from you were to point straight down, you would both be pointing in the same direction. And as the Earth turns, that direction would change for both of you. We are very small and near compared to Earth, so its gravity has a strong effect on us. But stars are smaller and far away relative to our solar system, so their gravity has less of an effect, sometimes even essentially zero (individually).\n\nAnother partial answer is that it is believed that if the universe has enough mass within it, it will indeed eventually (billions of years from now) begin contracting until it again becomes a single point (and then likely go through another "Big Bang"). For the most part, the stars and galaxies are moving away from one another at increasing speed, so the combined effect of gravity is decreasing. But if there is enough mass, the galaxies should eventually slow, then stop, then start moving back toward each other. This is what the questions over "dark matter" are about -- whether the universe will contract, or keep expanding forever.
905154
I think if nothing unbelievable happens (EG: Mass nuclear war, a new deadly air-borne virus, etc) I think the world will end when the sun goes supernova. All stars (I think ) go supernova, basically imploding in on itself but releasing a massive amount of energy. The world will get toasted and even though this will supposedly happen thousands upon thousands of years ahead of today, I doubt technology will be so good as to prevent this.\n\nWikipedia says this isn't possible because the Sun is too small but some notable sources disagree. Well, I'll be long dead so I'm not too bothered.
786267
It depends on the mass of the star in question. For example, a star is born, it grows old, it gets larger (Red giant stage) and it dies. Depending on its mass and newly discovered turbulence inside a star before collapse, it will either go supernova and create a planetary nebula and reduce to a white dwarf, or go supernova, continue to collapse and turn into a black hole. It all depends on the mass of the star, and the amount and directionality of the turbulence inside the star's core.
579859
I assume you mean "star" and not "sun", as in OUR sun, in the first question.  In that case, a supernova is essentially the spectacular explosion that occurs when a star of a significant sized mass ends its life.  IN that case, all the elements with a periodic table number higher than oxygen are created.  In addition, the remaining core of the dead star becomes so dense, that it creates an object that even light can't escape.  This object is now a black hole.\n\nOur sun is not big enough to supernova, therefore it will just die out and become a black dwarf when it is dead.\n\nDefinition from the Big Wiki...\n\nhttp://en.wikipedia.org/wiki/Supernova
3582
No, the Earth will continue in its orbit around the sun. But as the sun runs out of hydrogen fuel and balloons into a red giant, it will become so huge that Earth will be completely incinerated. Sorry to break it to you.
902366
Heres a web site that discusses the fate of stars of 20 solar masses and up:\n\nhttp://observe.arc.nasa.gov/nasa/space/stellardeath/stellardeath_3.html
202943
A huge, old star implodes and becomes extremely dense, such that even light cannot escape its gravity. See more through the link below.
732762
Their materials collect together (via gravity) and make new stars.  Granted, they tend to be made of heavier materials and burn cooler (often red).\n\nStars collapse when they run out of material.  A star begins by fusing hydrogen into helium.  Eventually, the hydrogen runs out and the star begins to collapse until it is able to fuse helium into carbon.  This continues through various elements until it is largely iron.  A star is simply not able to fuse iron into anything else (their not massive enough), so it eventually has a final collapse, sometimes into a supernova.\n\nThis final collapse can leave three possible "leftovers":\n1.  A white dwarf - if the star is less than 3 x the mass of our sun, then the core will be left as a burning ember.  Eventually it will burn out to become something known as a brown dwarf, a dead star.\n\n2.  A neutron star - if the star is between 3 and 10 (I think) x the mass of our sun, the explosion compresses the core down enough that protons and electrons are crammed together to form a neutron star.  It's a bunch of neutrons so dense a teaspoonful would weigh, well, tons on the earth.\n\n3.  A black hole - if the star is especially massive, the collapse never ends.  The core itself cannot overcome the massive gravity that is created by a now extremely dense remnant, forming a black hole.
28773
Probably just as big as it is now. Its diameter is 864,938 miles (109 times the size of Earth). \n\nThe sun is over 4.5 billion years old... so a billion years ago it was doing pretty much the same thing it is now. A lot of nuclear fusion going on. \n\nIt will stay the same size until it has used up its core hydrogen fuel, the star starts to fuse helium and eventually other elements. During this time the star will expand into a red giant or super-giant, becoming tens or even hundreds of times larger. Eventually, no more fuel will be available and the star will collapse under gravity to form a white dwarf star only a few thousand kilometres in diameter.
639748
That depends on the mass and composition of the star.  For an average one like ours, it's a little under 10 billion years.  More massive stars and those with higher amounts of lighter elements tend to burn much hotter, so they normally use up their fuel and leave the main sequence earlier than smaller and more dense stars.
23431
First, there is no way they can fall. Falling of things on earth is due to its gravity. Most of the heavenly bodies out there are much much bigger than earth itself (stars, planest like jupiter, neptune, saturn) and they are very far off. \n\nSo if at all you mean to say they collide, it will be like one gigantic explosion and earth will be ripped to pieces (even if something as small as our moon falls!) \n\nThere is no question of where they will fall. The collision point can be any place depending on where the earth is and considering its rotation.\n\n:)
866476
The reason you can see them is because they are falling....\nVery quickly down through the atmosphere...\nFast enough to burn them up...\nAnd the fact that they mostly burnout in a second is testement to the fact that the vast majority of these objects are much too small to make it to the ground before they are vaporized....\nSome do however... but then they are called meteorites...\nAt if one does fall on you its probably going to hurt...
359720
throughout a stars life-cycle, it is constantly heating materials (hydrogen and iron) and pushing them to the surface to cool, and to the center to heat up and melt.\nThis is part of nuclear fission.\n\nafter a very long time, the sun starts to lose energy, and cant push the iron up from its core and gradually grows larger, turning red (hence red giant),\nEventually, the pressure from its mass, and it's failure to push it all away from its core will result in the star collapsing into itself, potentially turning into a black hole.
46639
YES, and this is so cool check it out!\nhttp://static.howstuffworks.com/gif/space-station-flame.jpg\nIt burns in a perfect sphere!
145689
*Poking lordfarhad.rahimi* Please only post a question once...\n\nFar as the universe being unsteady, yes of course it is. That is the nature of the universe, it is not a steady, static thing. It changes and is chaotic. That is part of the beauty of our universe.\n\nNow, as to stars collapsing. Yes indeed they do, that is part of the life cycle.\n\nStars are born in nebulae. Huge clouds of dust and gas collapse under gravitational forces, forming protostars. These young stars undergo further collapse, forming main sequence stars.\n\nStars expand as they grow old. As the core runs out of hydrogen and then helium, the core contacts and the outer layers expand, cool, and become less bright. This is a red giant or a red super giant (depending on the initial mass of the star). It will eventually collapse and explode. Its fate is determined by the original mass of the star; it will become either a black dwarf, neutron star, or black hole.\n\nOur own sun will become a black dwarf in a few billion years...\n\nOn a side note, the universe itself is not collapsing, never fear. It is expanding and getting larger all the time.\n\nI've added some links that have great diagrams of this fascinating topic below.
563434
a meteor is headed toward earth so it hits the atmosphere, so you never see it again. the comet orbits the sun, so it does not burn up. the reason it does not burn up when it gets to close to the sun is because it orbits it, it does not crash into it.