Add Yahoo as a preferred source to see more of our stories on Google. Crew members aboard the International Space Station unpack newly delivered fresh fruit and other goodies in October 2019. (NASA) ...

Space is full of mysterious sounds, some of which even have explanations. But that's far from the case when it comes to this knocking sound heard decades ago.

When astronauts come back down to Earth, it can take a moment to adjust to the return of gravity. A viral video of NASA astronaut Tom Marshburn cursing gravity as he tries to place a pen mid-air was ...