Inner and Outer Spacewhere does it begin, your opinion.

  1. OK, so I work for an organization that deals with "space" 24/7 and controls satellites. We had a discussion today on whether INNER/OUTER SPACE starts at 100Km above the Earth or where the atmosphere becomes a complete vacuum. NASA says 50 miles...ect...

    My opinion is that Inner Space can be defined where the gravitational pull of the Earth reaches and Outer Space is where the gravitational pull diminishes. Some argued this point with "Our Solar System is acted upon gravitational pull by the Sun, the Milky way Galaxy and even the Universe."

    So where does it begin/end? Can this even be defined? Again...this seems to be a "your opinion" answerable question so...what is it?
  2. jcsd
  3. russ_watters

    Staff: Mentor

    I've never heard of "inner space" and I'm pretty sure NASA doesn't use a term like "outer space".

    In any case, there is no strict boundary between the atmosphere and space and there is no distance at which the earth's gravitational influence drops to zero. For the purpose of putting a criteria on who can be considered an astronaut, "space" is defined to be 100 km up.
  4. Back in the day inner space referred to under the surface of the ocean.
  5. I took a orbital dynamics class last year, and our definition was 130 km because that's apparently the lowest altitude at which an object can achieve temporary orbit.
  6. russ_watters

    Staff: Mentor

    Welcome to PF....

    That's, imo, a better definition than 100km because getting up to 100km doesn't really do anything useful for you.
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