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Destruction of a planet

  1. Nov 5, 2004 #1
    I have been wondering that is that possible a planet to be destroyed like what happened in Star Wars?
    Is it possible to destroy a planet?
    Will a planet destruct by itself?
    What are planet's vital point?
     
  2. jcsd
  3. Nov 5, 2004 #2

    mathman

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    A planet, or at least life on it, can be destroyed by a collision with something big enough, such as a large meteorite. Also a planet can fall into a star or a black hole.
    Highly unlikely. I can't think of any mechanism, although life can be destroyed by radical climate change or loss of atmosphere.
    For life - atmosphere, temperature, oceans. For the planet itself - can't think of any.
     
  4. Nov 6, 2004 #3

    tony873004

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    Maybe a planet spiraling into it's parent star. I wonder how long Earth would last once it crossed the Sun's photosphere? It would still be a dense sphere of rock, with LOTS of momentum.
     
  5. Nov 6, 2004 #4

    mathman

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    My guess is that before it reached the sun's surface, gravity would have torn the earth apart, so on impact it would quickly vaporize.
     
  6. Nov 7, 2004 #5
    Nah, I don't believe that, I think it moreover will be like putting something cold in boiling water, it creates a low-temperature region that will slowly warm up and mix with the sun.

    I don't really see how it could spiral into our sun? It would seem to me that it would obtain an elliptical orbit around it at any time you change it's velocity (however that would happen) like kepler's laws describe.
     
  7. Nov 7, 2004 #6

    mathman

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    Baring a collision with something enormous, the earth wouldn't spiral into the sun. However, in a few billion years, the sun will have used up most of its H and will expand into a red giant, which will envelop the earth.

    As for your boiling water analogy, remember the sun's surface is 6000 deg C and gets hotter as you go in. Moreover, the sun is much bigger than the earth, so the low temperature region will heat up very quickly.
     
  8. Nov 7, 2004 #7
    There are supervolcanos like what lies beneath Yellowstone Park that erupt every 100 million years or so. The Yellowstone one is due. It should wipe out all mammal life including us when it happens. If so, I am not too concerned about the fate of the planet.
     
  9. Nov 9, 2004 #8
    How bout this question? Is there any way that we destruct a planet by ourselve?
     
  10. Nov 9, 2004 #9

    cepheid

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    Why? Did you have something in mind? :smile:
     
  11. Nov 9, 2004 #10
    HAHAHA, nope, just for knowledge ~ anyway, i think it might be better if you private message me the answer..

    ~ PREVENTION ~
     
  12. Nov 9, 2004 #11
    There's a very good article on this, written by Phil Plait, I'll quote part of it here:

    It's really hard to blow up a planet! It's possible that the alien technology did something like cause a chain reaction which totally disintegrated the atoms, or something like that.

    But that's no fun. Well, it might be fun, but really, how much energy does it take to blow up a planet? I did this calculation once before, to show that a comet impact could not destroy a planet. To blow up a planet, you have to overcome the gravity of the planet for each piece. Let's put it another way: Imagine taking a rock and throwing it up so hard it escapes from the planet entirely. For the Earth, that means you have to give it a pretty big velocity, about 11 kilometers per second. It takes a lot of energy to do that, the amount of which depends on the mass of the rock and the amount of gravity you are fighting. Now take another rock, and do it again. And again. And againandagainandagain. Repeat for a gazillion times. If you do it enough times, the planet is gone. You've destroyed it. Congratulations!

    It's possible to calculate that total energy you expended. It's called the gravitational binding energy, and is basically the amount of energy locked up in the planet's gravity. I'll spare you the math (but you can find it here if you'd like), but for the Earth that energy is roughly 1039 ergs. An erg is a tiny unit of energy, but 1,000,000,000,000,000,000,000,000,000,000,000,000,000 is a lot of them! For comparison, the Sun puts out about 4 x 1033 ergs every second, so the amount of energy needed to vaporize the Earth is about the total amount of energy the Sun emits in 3 days! That's a whole lot of energy. I doubt a single ship could generate that much. But who knows? They're aliens!


    Further details can be found on the following website http://www.badastronomy.com/bad/movies/mib2_review.html, where the author is discussing the science in the movie 'Man In Black 2'. It's a really cool website, highly recommended.
     
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