Here's How Cold Outer Space Really Is

Hollywood tells us that space is cold. Really cold. When Khan groused about Captain Kirk and swore to take out his wrath on the Enterprise, he noted that revenge is a dish best served cold, and space is very, very cold. Touche. When Yondu sacrificed himself for Star-Lord, he froze solid within seconds of being exposed to the vacuum of space. So we get it, Hollywood. Space is super-cold. But is Hollywood telling us the truth? Is space really that cold?

Actually, no, not precisely. Because space has no temperature and technically speaking, the question itself doesn't even make any sense. "It's only when you put a thing in space, like a rock, or an astronaut, that you can measure temperature," says Universe Today. Conduction (the transfer of heat via physical contact) and convection (air moving heat around) can't happen in space, so the only process that can transfer heat in outer space is radiation. An object that loses more photons than it absorbs cools down; an object that absorbs more photons than it loses heats up. So in space, if you're in the path of the light from a star, it can get really danged hot. If you're not in the path of a star's energy, it will get really, really cold. 

Seriously, though, how cold is outer space in practice?

The farther away from the star you get, the colder you will become — but here's where it gets interesting. The coldest possible temperature no matter where you are is absolute zero, which is -459.67 degrees Fahrenheit. But it's also not possible for anything to ever be that cold in reality. Even in the farthest reaches of space, objects will never reach temperatures lower than -454.81 degrees Fahrenheit, which is the temperature of the microwave background radiation that is present throughout the entire universe. So in space, you will certainly freeze solid just like Yondu did. And objects in space will become as cold as it is possible to become. But space itself is not technically cold.