Why if a meteor of great size hit the planet  would there be a giant explosion?
604083
Obviously, it's not an actual explosion, but the effects are very large.  Let's take the one that's supposed to have killed off the dinosaurs.  The meteorite was very large - I don't have the scientific estimates in front of me, but at least a kilometer in diameter, probably more.  Now this thing is big and moving at a very high velocity; it has lots of kinetic energy.  When it hits the earth, the meterite stops moving, but according to the Law of Conservation of Energy, the energy can't just disappear.  Instead, it has to be changed into other forms such as sound, heat, and vibration.\n \n Also, there's Newton's law that says for every action there is an equal and opposite reaction.  If you throw a ball at the ground it will bounce back, but if the ball has no elasticity and can't bounce, then the ground itself (part of it, dust etc.) will bounce back instead.  That's what happened when the meteorite hit earth.  Only, of course, it was a lot bigger than a ball, and the crater it created was between 180 and 300 km across.  It's in the Yucatán Peninsula in Mexico, if you're interested.
56902
It would burn up upon reentry in the the earth's atmosphere.
709262
Don't forget that large bodies like the earth itself, and the sun, are themselves held together with gravity.\n\nProbably the first thing that we would notice is that the earth would immediately lose its atmosphere as it went flying off the planet into space, as would the oceans.  Everything on the surface of the planet would go flying off due to the centrifugal force of its spinning ... buildings would just rip off their foundations like cheese shaking off a cheese-puff.  Without an atmosphere, it's doubtful you and I would live more than 15 or 30 seconds.\n\nThe earth  would immediately break apart in a big cloud of hot liquid iron (the core of the earth) and all the stuff on the surface.\n\nThe moon would also disolve into a huge cloud of hot rocks and sand.\n\nThe sun would explode rather violently, as the pressure from the burning of the inner core would suddenly have no force counteracting it.  The same would be happening to every star and planet in the universe.  And galaxies themselves would fly apart (as they too are held together with gravity).\n\nAnd yes, what is left of the earth would fly away from what is left of the sun ... although it would be quickly overtaken by the exploding sun.\n\nBut, of course, it ain't gonna happen.  I'll bet everything I own on it.  :-)  \n\nThink of this as a great way to get back in with your girlfriend ... "Hey baby, if gravity were suddenly to disappear, we need to be holdin' each other really tight!"  (You take it from there).
169798
With only your vague description to go on and a year you arent sure of, it is very hard to ansswer your question, but I assure you, you did not see the "biggest explosion since big bang".\n\nPerhaps it was a meteor exploding in the atmosphere?
976524
From the various reading I've done on this subject, as well as the educational programming I've watched about it, I'd say that all things considered, a volcanic eruption, like that of the 1883 explosion of Krakatoa, is by far the most violent and has the most and the longest-lasting consequences not only on the area in which the volcano erupted and the area the lava reached, and not only the areas affected by the resulting tsunamis, its effect actually includes the entire planet, since such an eruption is violent enough to change the entire planet's climate!\n\nWith a volcanic eruption you have: rocks of all sizes, including those the size of houses, hurled out like torpedoes, hot lava that incinerates everything in its path, hot gasses that not only expand, creating a pressure front, not only also incinerate, but also form acids that dissolve the various objects in their path, massive earthquakes, massive tsunamis and last, but most certainly not least, a thick cloud of ash, particles and gasses that wreak utter havoc with the atmosphere and the planet's general climate, thus disrupting wind currents, ocean currents and the general climatic-atmospheric signature of the planet. Consequently, even those places that were nowhere near the volcano, nowhere near the radius of the area the lava will reach, nowhere near any coast that would be affected by the resulting tsunamis, it will still be affected by the falling rocks and debris, which were spewed up into the atmosphere, as well as by the climatic disruptions.\n\nTo my knowledge, not even earthquakes, regardless how violent, can match that level of and extent of destruction, despite the fact that they cause massive fires and potent tsunamis!\n\n\nNote: I took a very "flexible" interpretation of the word storm. I took it to mean any weather/climatic phenomenon/activity. Thus, in that sense, a volcanic eruption can be interpreted as a storm, even though it is not a current of air or water or both!  But, then again, if that type of climatic activity is not to be considered a storm, then what else can it be called? It is ludicrous to lump wind & water weather events together under the title storm, yet consider volcanic eruptions, earthquakes, tsunamis & mudslides, to name a few, categories & titles in of themselves!
85695
Meteors are constantly hitting the Earth.  Most of them are small and burn up in the atsmosphere.
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...
847308
It's a bit complicated.  The Earth's magnetic field is powerful enough to minimize charged particles from the solar wind, and the atmosphere attunates almost all other particles.  However, when a star goes nova, two jets are created at the poles.  These jets are extremely powerful with respect to the rest of the explosion.\n\nTherefore, if the Earth were not in the line of sight of the jets, the atmosphere and magnetic field would be extremely effective, and a supernova would have to be with a few 10s of light years to be dangerous.  However, if the Earth were in a line of sight of the jets, then during a few seconds the Earth could be bathed in deadly radiation, even if the source were a thousand light years away.
35245
There are an unlimited amount of craters on the Moon. In fact, the Moon continues to be hit everyday. This is especially true when we experience a meteor shower down here on Earth. A meteor shower occurs when the Earth intercepts an orbit of a comet that has debris in it. Since the Moon also intercepts this debris, those cometary particles cause impact creaters on the Moon because it has no atmosphere to stop the particles that look like shooting stars in our sky. When the Apollo crews returned with lunar samples and they were studied under a microscope, there were abundant microscopic craters in those samples. The largest craters can be several hundreds of miles wide. In fact the "Man on the Moon's" eyes are both ancient (4+ billion year ago) craters that filled up with lava.
1124844
If something was to hit us it would only be visible with the naked eye as it tears through the atmosphere, minutes before impact. The likelyhood is that an asteroid of very great size would be spotted  through telescopes years before it hits us. Scientist are studying near earth objects that might have the potentian of hitting us:\nhttp://www.spaceweather.com/ (scroll down)\nHowever, only 793 are know so far, while the total number is estimated at 2000.
1138910
No, and something from outside it would have to break Jupiter apart if it came apart, and if it did, the number and size of pieces it broke into would depend on what hit it, how big it was, and how fast it was traveling first.  And it would have to be much bigger than Earth to do any damage to Jupiter.  There are many other things to be concerned about - like bad movies.
488119
depends on how big it is when it enters the atmosphere
1001885
It would do nothing.  In 1994, a comet (Shoemaker-Levy) crashed into Jupiter.  I don't have the exact numbers on the equivalent to a nuclear bomb, but it was much more powerful than any bomb.  Jupiter kind of sat there and shrugged it off without much effect.\n\nEdit:  Found a site that says *one* fragment of the comet was the same as 225,000 megatons.  The biggest fragment was the same as 6 million megatons.\n\nhttp://www.isc.tamu.edu/~astro/sl9/cometfaq2.html
403604
it would probably cause widespread earthquakes and tsunamis, and it is possible that dust from the explosion ejected into the upper atmosphere could cause reduction in daylight . The physical effects could kill millions of people and destroy cities and towns. There could be extinctions of vulnerable plant and animal species. However in the long term, plant and animal life would recover, there would likely be a 'evolution explosion' as plants and animals move quickly to recolonise devastated areas.\n\n'Civilisation' as such would not be set back, as no knowledge would be lost, it would not be comparable to living in 1806, electricity, automobiles and so on, would not have to be discovered or reinvented, however human priorities would be altered in the short term with survival, food and shelter being most important
431791
when a meteoroid enters the atmosphere and burns up it produces a meteor.\n\nhttp://en.wikipedia.org/wiki/Meteor
375127
As a scientific mind and an individual who is curious, I would like to know. Then I could find a location to watch the impact with my family so I would know such a rare occurance and then die happily. Of course, an asteroid cannot destroy a planet unless it is planet-sized, and there are none left; an asteroid can only cause massive extinction events like the K-T impactor (aka "The Dinosaur Killer"), and probably cripple the human race. Watch "Deep Impact"; it's the most accurate movie made about such a thing thus far.
381332
The earth will not explode.  No, whoever said the sun will go supernova failed pre-k.  Ignore them.  Anyway, the earth can not explode, nor can any other planet pretty muc.  The Astroid belt would be to small to be a  destroyed planet, for it would be smaller than pluto if all the rocks were to be put together.  The only way the earth could exploide is with the colision of and object about 4x the size of earth if it was solid...and that, by almost all laws of physics, is impossible.\n\nEdit:\n\nOh, your also asking for the end of the world.  Very well.\n\nThe sun is 4.5 billion years old scientists estimate.  The sun eventually, in 4.5 billion years, swell into a red giant.  It will expand very far, and the earth will be engulped.  Plant life will die, the earth will become dry, and very few organisms will survive.  Eventually, the heat will evaporate the atmoshpere away.  The sun might swallow up the earth, and the earth will be devoured and broken apart from gravity if im correct.  Edit any posts and correct me if im wrpong.  If im not wrong and you correct me, watch how badly I flame your ***\n\nEdit2:\n\nOmfg how many people dont understand!  My god, you idiots!  Comon, a planet getting sucked into a blakc hole?!  YOu retatrds!  Your kidding me right? If your actually voted as the best answer, then the world truly will explode!  You people know nothing in life!\n\nAnyway, at the guy who says the earths core is a neuclear reactor:\n\nThe earth yes might be getting hotter, but that is no reason for it to explode.  Im not saying im with the media, Im only saying that the earths not in any real danger yet.  Im saying that I think It will last some time...but you do have a pont.  I'll do some looking into it.  Gotta show this to my buds on other forums.  Afk.\n\nPs. Good job for playgerizing the whole article but 2 words, by the way!