Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How High is Space?

  1. Sep 4, 2014 #1
    Look up, there’s space. Astronomically speaking, it’s right there, just outside a thin layer of atmosphere. But how far away is it? How high is space?
  2. jcsd
  3. Sep 4, 2014 #2
    As far as space goes, there is no end. Because space is relatively nothing, its infinite.
  4. Sep 4, 2014 #3


    User Avatar

    Staff: Mentor

    The Kármán line, at an altitude of 100 km, is typically used as the start of space and the end of the atmosphere, but not always.

  5. Sep 5, 2014 #4


    User Avatar
    Science Advisor
    Homework Helper

    Not always because the Karman line considers the impact the atmosphere has on aerodynamic flight, but ignores the impact the atmosphere has on orbital flight. You'd actually have to be a bit higher than 100 km to achieve at least one entire orbit.

    But at least 100 km is a nice round number.

    And it is the most common definition, in spite of its shortcomings.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook