free space

Discussion in 'General Science' started by samjesse, May 27, 2014.

  1. samjesse

    Thread Starter Active Member

    Sep 14, 2008
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    0
    Hi

    Please help me understand this or correct my understanding.
    Vacuum is the absence of air from a given space.
    Outer space has no air, so it is vacuum. "how much" reading in-Hg?
    Then why air does not move off to space since it is all vacuum. Does not air under pressure move to area of less pressure "vacuum"?

    Thank you
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Gravity is the Great Compressor. Lighter gases, the ones that float to the top, are generally lost due to solar winds on Earth.

    Jupiter is almost all gas, and hydrogen to boot, but it has no problem keeping it's atmosphere tightly bound.

    The Sun is vastly huge compared to planets, and has a continuous thermonuclear explosion to boot, but is barely shrinking. The amount of solar wind is infinitesimal compared to the total mass of the sun.

    The moon, on the other hand, does not have a deep gravity well. So it has no atmosphere to speak of, though there is a bit of one.
     
  3. bertus

    Administrator

    Apr 5, 2008
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    Last edited: May 27, 2014
  4. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
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    Dont let Kansas hear about "free space" they will find a way to tax it.
     
    studiot likes this.
  5. samjesse

    Thread Starter Active Member

    Sep 14, 2008
    202
    0
    LOL.

    Read my lips "no new taxes".:)
     
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