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Atmospheric pressure & the vacuum of space

  1. Jul 22, 2012 #1
    I have a question I long pondered and couldnt find any explanation to exactly what I want.
    We all know that atmospheric pressure is due tu gravity acting upon everything on earth. this pressure act from all directions on all our body molecules.

    However in space there is no gravity, no air, no such pressure, right? well, how can any shuttle, let alone astronauts get in ONE piece in space in the first place! shouldnt they explode from the inside out? shouldnt their molecules go apart because of the lack of the pressure?

    There was one experiment where a steel cube-put inside a partial vacuum box- melted or detached from itsself apart internally. which makes perfect sense since without pressure matter cant hold itself.

    Im really puzzled

  2. jcsd
  3. Jul 22, 2012 #2


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    No. Because the lack of pressure - the sucking force, isn't that strong. If you notice astronauts when they're doing a space walk, their suits puff out - in normal pressure the suits are floppy. That's as strong as the vacuum gets.

    That didn't happen. And matter holds itself together in the vacuum by all the other forces.

    If the vacuum was infinitely strong it would suck all of our atmosphere out into outer space - this does not happen.

    There are vacuums all around you. Nature may abhor them, but it doesn't mean they're impossible. An ordinary light bulb, has a vacuum in it - to stop the tungsten burning. If the vacuum breaks the tungsten burns.
  4. Jul 22, 2012 #3
    Alright. let me just explain a little further, I by no means understand exactly this.

    on both sides of your hand you have tremendous pressure, if you were to remove the pressure on 1 side of your hand, your hand would be thrown out/cut off by the left opposing pressure from the other side. all this pressure is removed in vacuum, so how are there no effects, that is what I still dont understand
  5. Jul 22, 2012 #4


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    Staff: Mentor

    Spaceships are pressurized. The materials used can quite easily handle the few psi of pressure.
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