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Why won't objects fall out of orbit

  1. Feb 16, 2016 #1
    I kind of understand how orbit works. So an object falls 10 feet then the earths curve counteracts the 10 feet, so it's prevents the object from just crashing down to earth. But wouldn't the object slowly either come closer to earth or go away from earth. As in like millimeter by milimeter.
     
  2. jcsd
  3. Feb 16, 2016 #2

    A.T.

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    That happens in elliptic orbits.
     
  4. Feb 16, 2016 #3
    Energy is conserved. You would need some mechanism for energy loss, such as friction, for objects in orbit to collapse and fall to Earth. Friction does exist, but the atmosphere is so thin in space that orbits can last for a very, very long time (depending on how high up it is).
     
  5. Feb 16, 2016 #4
    Both of those things happen.
    The moon is getting farther from us at about 38mm/yr. The tertiary sources I browsed (BBC, Universe Today) state this is due to tidal effects.
    The ISS experiences an orbital decay of about 2 km/month. This is caused by atmospheric drag, iirc.
     
  6. Feb 16, 2016 #5
    being in orbit is falling !!! look up newtons explanation of orbits
     
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