Question: @all scientists-When Astronauts travel into space do their spines expand and why?

Jason King answered on 19 Mar 2013:

Here on earth, the gravity we feel is constantly squashing us down, so we get compressed and our spines get shorter. In space however, because there is no gravity, our spines don’t have to cope with our body weight, so stay a bit longer and we get taller. Unfortunately, as soon as we come back to earth, they soon go back to their normal size!