Space! The final frontier, as they say.

But did you realize that space itself has a frontier? A border, if you may.

No, silly, as you travel into space, you're not gonna hit a brick wall. (Unless the Rigelians built one around their planet.) It has a border on this, Earth's sides of things.

That border is called the Karman line, after Hungarian Jewish mathematician and aerospace engineer Theodore von Karman. He was the first director of the Jet Propulsion Laboratory (JPL).

So where is this line? It's at a radius of 100 kilometers above the Earth's surface, where, according to Karman, "aerodynamics stops and astronautics begins". The line is determined by the denseness of air needed to support flight; the 100 km is not precise, as it varies on a number of parameters.

Now, even though we joke about the Rigelians, theoretically, any other planet would have its own space frontier... Potentially named after its own aerospace engineer?

We wouldn't bet on any Rigelian scientist being Jewish...