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Moon Question (Vacuum, air, escape vel.)

  1. Sep 28, 2010 #1
    Ok, this might seem like a silly question, but I just want to get it straight. Just tell me if anything I am saying is wrong, and answer the best you can.

    Ok, the moon has no air, because it has no atmosphere correct? And the reason for no atmosphere is because the moon is biologically non-active, and the moon does not have enough mass to keep things from escaping the moon, including gases, which the moon does not give off because its biologically dead ?

    The moon is simply apart of the vacuum of space because of the atmosphere correct?

    So, the reason someone on the moon would not drift off into space if they jumped in the air is because the moon still of course has gravity, as everything with mass has gravity.

    Now its your turn :)

    Thanks guys!
  2. jcsd
  3. Sep 28, 2010 #2


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    Having an atmosphere doesn't necessarily mean having air...

    This doesn't make much sense to me either. "Apart of the vacuum of space?" Vacuum is, by crude definition, the absence of matter.

  4. Sep 28, 2010 #3


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    fss covered most of it. A few tweaks:
    Planets certainly off-gas without being biologically active. Europa is spewing sulphur clouds from its interior.

    But Europa is tectonically active; it has a liquid core. The Moon's core has long since cooled and is now dead. That's why it does not off-gas.

    Well, of course, they couldn't "jump in the air" on the Moon, could they? :wink:

    But yes, gravity is what holds things down, not atmo.
  5. Sep 29, 2010 #4
    Io is the volcanic one. It has a thin atmosphere of mostly sulfur dioxide from all the sulfur and the like. During Io's night the atmosphere freezes, then defrosts just after dawn. Europa has a very, very thin atmosphere of oxygen, from ice that has been exposed to Jupiter's radiation belt and broken into oxygen and hydrogen.

    The Moon BTW doesn't have an atmosphere because it was blown away, long ago, by the Solar Wind.
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