Andrey Armyagov/Alamy
If time changes as a result of the speed of space travel, do the cells in an astronaut’s body still multiply at the same rate?
Ron Dippold
San Diego, California, US
It is all relative. The simple answer is yes for the astronaut, no for someone (relatively) stationary watching them. To the astronaut and anyone with them, their cells are still growing at the usual rate. Their hair and nails need to be cut just as often.
To an observer just sitting in a chair on Earth, though, the astronaut’s cells will appear to be growing slower. The International Space…
