Where does space begin? (NASA / Thinkstock)
Where does space begin?
Lexile

You asked us, where does space begin?

Amazingly enough, there isn't an answer to that question. At least not one that's internationally agreed upon and legally binding. Which makes sense, because our atmosphere that thin sheet of air that wraps our planet doesn't end abruptly. It gradually thins out.

Coming back down to earth, let's say you wanted to turn your astronaut wings from the U.S. Air Force. How high would you need to fly? Well, get yourself more than 50 miles above the planet's surface and you're golden.

If you're looking to set a world record, though, the International Air Sports Federation raises that bar to 62 miles, the minimum altitude necessary to be considered a space flight. That limit is named after Hungarian scientist Theodore Von Karman.

He suggested it in the 1950s, because above it, normal aircraft wings become useless. Which is just one of the many, many reasons why space flight is tricky business.

For more stories like this, check us out every day, at Smithsonian.com.

Critical thinking challenge: Where does space end?


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COMMENTS (128)
  • MCS2001softball
    4/15/2015 - 08:39 a.m.

    I think that it is pretty cool that the universe, the place we call our home, never ends. Just thinking about this makes me wonder if we really are the only life forms in the universe or if there are some other beings out there that are wondering the same thing about thaemselves.

  • D.F2001Rex
    4/15/2015 - 08:48 a.m.

    Space is amazing and i am not really surprised that scientists can not find out where space began. The universe is huge and it is constantly expanding. Did you know that the universe is expanding by 68 kilometers per second per megaparsec. That is really cool but scientists don't really know why or how galaxies are moving away from us.

  • TrevorZ-Bru
    4/15/2015 - 12:53 p.m.

    I think the main idea is that space doesn't really begin. Space gradually thins out from our atmosphere. Even if space did begin there is not an internationally agreed upon spot. So there isn't even an exact answer to the question.

  • CT14
    4/15/2015 - 12:58 p.m.

    Space doesn't have an exact answer to where it starts? Funny i always thought it started once you left earth's atmosphere. But the fact that our atmosphere doesn't end but thins out makes everything seem more strange then i originally thought.

  • cc2000ProEra
    4/15/2015 - 01:00 p.m.

    Space is never eneding and infinite so theres probably another habital planet somwhere out there. There is probably also another living thing out in space too. This article was really good.

  • AC1999jamaica
    4/15/2015 - 01:04 p.m.

    space is one of the most fasitnaing things i know. the plantes the stars black holes and glaxeys endless space. I wounder if theiris a end ot spaces.

  • KathyM122
    4/15/2015 - 02:57 p.m.

    No answer! Noooo but that question is probably never going to get answered at least not anytime soon. It would be really cool to know more about space only if it wasn't that deadly.

  • JEstrela915
    4/15/2015 - 03:13 p.m.

    Wow thats a bit crazy how know one will ever know when space ends it is just a LARGE Sheet Of Darkness And It Just Spreads In Spreads In Spreads it Could Be Spreading Right Now!

  • max_5201
    4/15/2015 - 05:30 p.m.

    I cant believe we don't know were space begins. We have so much technology these days that its almost amazing that we don't know were space starts or ends. I kinda wish we did know how far we would have to go to see the end of space and I wonder whats there.?

  • max_5201
    4/15/2015 - 05:31 p.m.

    I cant believe we don't know were space begins. We have so much technology these days that its almost amazing that we don't know were space starts or ends. I kinda wish we did know how far we would have to go to see the end of space and I wonder whats there.?

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