Astronauts always fold their arms in space - but it's not to look cool

Scott Kelly/NASA

Scott Kelly is a cool guy. In addition to being, you know, an astronaut, he's also the first American to live in space continuously for an entire year. He just surpassed his 300th day up there.

He also looks pretty unflappable in this photo, with those crossed arms and that stern grin. In fact, many astronauts take photos like that.

But that posture isn't just for the sake of exuding vigor and resilience - it actually serves an important purpose, Kelly revealed January 23 in a Reddit AMA (ask me anything).

"Your arms don't hang by your side in space like they do on Earth because there is no gravity," Kelly said in response to user Doug_Lee's question about the deal with astronauts and folded arms.

"It feels awkward to have them floating in front of me. It is just more comfortable to have them folded," Kelly wrote (or rather, someone at NASA wrote for him as he spoke from space).

NASA

ESA astronaut Luca Parmitano and Russian cosmonaut Fyodor Yurchikhin watch the Cygnus launch in the Destiny laboratory aboard the ISS in September, 2013.

It's a simple solution to a complicated problem. Who wants to walk around the space station looking like Frankenstein?

Kelly even assumes this arm posture when he's getting some shuteye: "I don't even have them floating in my sleep," he said during the AMA. "I put them in my sleeping bag."

It's a great example of the many adjustments astronauts must make when living in the near zero gravity conditions, including the way they season their food, keep track of time, cry, and use the bathroom.

Something to think about when you're getting all brash with your gravity and your normal-hanging arms on Earth.