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    The Edge of Everything: Defining Space

    12 min
    |
    18 sources
    |
    Jan 13, 2026
    ScienceTechnologyNature

    Explore where Earth's atmosphere truly ends and space begins, from the conventional Kármán line to the surprising reality that 'perfect vacuum' is a myth even in the cosmos.

    The Edge of Everything: Defining Space

    This audio lesson was created by a BeFreed community member

    Input question

    Space

    Host voices
    Lenaplay
    Milesplay
    Learning style
    Quick
    Knowledge sources
    The Future of Humanity
    A City on Mars
    Future Stories
    Exodus
    Moon
    A Brief History of Time

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    "Reading used to feel like a chore. Now it’s just part of my lifestyle."

    @Erin, Investment Banking Associate , NYC
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    "Feels effortless compared to reading. I’ve finished 6 books this month already."

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    Key Takeaways

    1

    Where Space Actually Begins

    0:00

    Lena: Hey there, space enthusiasts! Welcome to another mind-expanding episode. Miles, I was thinking about this the other day—when we say "outer space," what exactly are we talking about? Where does Earth's atmosphere end and space actually begin?

    0:15

    Miles: That's such a great question, Lena. You know, it's not as clear-cut as you might think. Most people recognize something called the Kármán line, which sits about 100 kilometers or 62 miles above sea level, as the boundary where space begins.

    0:30

    Lena: Wait, so there's an actual defined line? Like, you cross it and suddenly you're officially an astronaut?

    0:36

    Miles: Well, yes and no. The Kármán line is what's conventionally used in space treaties and record-keeping, but it's more of a human construct than a natural boundary. The atmosphere actually doesn't just stop—it gradually thins out. In fact, did you know that the International Space Station orbits in what's technically still considered a region with some atmospheric drag?

    0:57

    Lena: That's fascinating! I had no idea. So space isn't actually the perfect vacuum most of us imagine?

    1:04

    Miles: Exactly! Even in what we call "outer space," there's still matter—mostly hydrogen and helium plasma, along with cosmic rays, dust, and dozens of organic molecules. Let's explore what makes space such an extreme environment and how humans have managed to venture into this challenging frontier.

    2

    The New Golden Age of Space Exploration

    3

    The Race to Become a Multi-Planetary Species

    4

    The Technology Revolution Enabling Our Cosmic Future

    5

    The Search for Life Beyond Earth

    6

    Your Personal Space Age Action Plan

    7

    Looking Up at Tomorrow's Infinite Possibilities

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