You may have heard people refer to the “edge of space” – 100km – as the Kármán line. But what does that mean, and what’s so significant about it?

Simply put, the Kármán line is loosely defined as the altitude at which a fixed-wing aircraft would need to travel faster than orbital velocities to produce enough lift. This is a bit of a complex concept to understand, so I’ll break it down.

What is space?

Let’s fall back to a question that’s easier to answer. Or is it? “Space” typically means “outside of the atmosphere”; for example, we consider the ISS, at