We already know that the human body cannot survive being ejected into the vacuum of space. We've seen it in the movies, and it's not pleasant. But that's where this TED-Ed lesson starts, because they want to cover all the scenarios. With a spacesuit, a body is much safer, but still not safe because we are exposed to conditions that don't occur on earth, like unshielded radiation. So astronauts travel in spaceships, to a space station that's built to keep them safe. But is it really safe? Even with strict environmental controls, astronauts must deal with microgravity in bodies that evolved to work properly in earth's gravity. It takes a while, but even that will damage the human body in surprising ways. These findings might put a damper on your desire to volunteer for interplanetary travel. Find out more in our previous posts on NASA's twin study of a year in space. -via reddit