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Supernova shockwave

  1. May 24, 2012 #1
    I was wondering if a shockwave from a supernova is finite or reacts as energy and dissipates over distance.

    The reason I'm asking is because i'm wondering if a supernova could give solarsystems, planets and basically anything with matter a nudge. Then could the objects in space act like a ion drive. Where over millions of years all the supernova's would increase the expanding speed of the original big bang.

    ps with Ion drive I mean travelling through space with an Ion drive shooting small burst of energy. Since motion is endless in space all these tiny burst end up and in time you would be moving incredibely fast.

    Why would this not apply to any object and explosion in space? Even if the effect would be unmeasureably small over biljon of years that could add up?
  2. jcsd
  3. May 25, 2012 #2
    The energy is finite. It therefore does dissipate. I'm not clear why you would think it could be any other way.
  4. May 25, 2012 #3


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    The "shockwave" is important for the supernova remnant itself. If it is asymmetric, it can gain significant velocity. It also affects stars and planets that are very near.
    Over larger distances, the effect is unmeasurably small. Sure, it does add up, but so does gravity, which remains overwhelmingly stronger therefore.
  5. May 26, 2012 #4

    Supernova shock waves do trigger new star formation.

    Nope. Too small. Supernova shock disappear over a few hundred light years. The universe is billions of light years.

    Not really. One thing about waves is that it's possible to get hit by a wave and not move very much. Look at a water wave. The material moves back and forth, but it doesn't impart much acceleration.

    Once the shock wave goes into the interstellar medium, it get's hot and dense, but things don't move very much.

    Space is big. Really big. Stars are tiny and the energy from supernova doesn't add up to much.
  6. May 26, 2012 #5
    Depends on what you mean by "large". Supernova shock waves probably affect the interstellar medium within 100 light years or so. The effect of shock waves in the interstellar medium is quite large because the medium is not very dense.
  7. May 26, 2012 #6


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    By "large" I mean more than far, far less than a lightyear.
    But by "effect" I mean significant propulsion of stars or planets as in the OP, not compression of interstellar gas and such. Gas will sooner or later take all the energy of the shockwave, but solid bodies are (kinematically) not significantly affected except in the rare cases I mentioned.
  8. May 26, 2012 #7
    You have to be careful here. If you are close enough to the supernova, it's more likely that the planet is going to get vaporized by the shock wave than moved. Of the top of my head, I don't know what the distances are, but it would make a cool problem on an astrophysics problem set.

    The other thing is that you have thunder and lighting. The shock wave is the thunder since it moves at the speed of sound. The initial burst of radiation is the lightning and that moves at the speed of light. If you are close enough, then radiation pressure from the initial burst will push planets assuming that they don't get vaporized.

    Also there are a lot of high velocity objects


    The idea is not that they were pushed by the shock wave, but rather they were orbiting around a star that went supernova and so that when the supernova went boom, they just zipped out of the system.
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