The answer comes from a counterintuitive result of special relativity, a field of physics which is notoriously difficult to ...

Twin brothers and former NASA astronauts Mark and Scott Kelly have each flown four missions and were part of NASA's twin study to research the impact of spaceflight on the human body. Hours before ...

During a recent visit to Houston, Mark Kelly was drained of 20 tubes of blood and spent several hours in an MRI machine. He was scanned while lying down, standing up and on an incline. When he was in ...

He drew blood from his arms. He saved his urine. He played computer games to test his memory and reaction speed. He measured the shape of his eyes. Two hundred-and-forty miles below, Scott’s twin ...

Long-duration spaceflight does weird things to the human body, even at the molecular level, but so far there’s no reason to think humans couldn’t survive a two-and-a-half-year round-trip journey to ...