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.

From Columbia University alumni built in San Francisco
"Instead of endless scrolling, I just hit play on BeFreed. It saves me so much time."
"I never knew where to start with nonfiction—BeFreed’s book lists turned into podcasts gave me a clear path."
"Perfect balance between learning and entertainment. Finished ‘Thinking, Fast and Slow’ on my commute this week."
"Crazy how much I learned while walking the dog. BeFreed = small habits → big gains."
"Reading used to feel like a chore. Now it’s just part of my lifestyle."
"Feels effortless compared to reading. I’ve finished 6 books this month already."
"BeFreed turned my guilty doomscrolling into something that feels productive and inspiring."
"BeFreed turned my commute into learning time. 20-min podcasts are perfect for finishing books I never had time for."
"BeFreed replaced my podcast queue. Imagine Spotify for books — that’s it. 🙌"
"It is great for me to learn something from the book without reading it."
"The themed book list podcasts help me connect ideas across authors—like a guided audio journey."
"Makes me feel smarter every time before going to work"
From Columbia University alumni built in San Francisco

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?
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.
Lena: Wait, so there's an actual defined line? Like, you cross it and suddenly you're officially an astronaut?
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?
Lena: That's fascinating! I had no idea. So space isn't actually the perfect vacuum most of us imagine?
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.