Why astronauts age slower while they’re in space

  • Astronauts age slower in space than they do on Earth
  • The reason why links back to Albert Einstein’s Theory of Relativity
  • This could have implications for space travel in the future

Published on Jun 28, 2024 at 7:31 PM (UTC+4)
by Ben Thompson

Last updated on Jun 29, 2024 at 4:09 PM (UTC+4)
Edited by Tom Wood

With many people on the lookout for anti-ageing treatments, who knew that astronauts had the secret?

Spending time in space will do more to diminish wrinkles than any moisturizer down on Earth.

Not that you can book a trip to space at your local chemist, of course.

READ MORE: Three astronauts miraculously managed to survive getting lost in space 50 years ago

Why do astronauts age slower in space?

The reason why astronauts age slower in space than on Earth links back to Albert Einstein.

Einstein’s theory of relativity, to be exact.

The theory goes like this – time is not a constant but rather a variable that is influenced by speed and gravity.

Hence why astronauts age slowly when they’re in orbit, as they’re experiencing time differently from the rest of us down on Earth.

Gravitational time dilation means that the presence of mass changes the fabric of spacetime.

As a result, time passes differently depending on the strength of the gravitational field.

Those in space, away from Earth’s gravitational pull, experience time at a slighter faster rate.

There’s also relative velocity time dilation to consider, in which speed impacts the passage of time.

The faster an object is moving, time appears to slow down for that object from an observer’s perspective.

Astronauts traveling through space experience this dilation.

Is there any proof for the ageing process slowing down in space?

The ‘Twin Paradox’ is often cited as proof of this phenomena.

If one twin goes into space and the other stays on Earth, the Earth-bound twin will appear to have aged more than his space-exploring counterpart.

What does this mean for astronauts who spend months at a time out in space?

According to the European Space Agency, astronauts on the International Space Station age less than those on Earth by 0.005 seconds.

That may sound like nothing, but it’s significant in proving Einstein’s theory to be correct.

As we look to expand space travel further and further, the implications of his theories will be increasingly significant.

If an astronaut were to go to a far-off planet, they could return significantly younger than their fellow Earth dwellers.

# Tags - Science, Space


Ben Thompson

Ben got his start in journalism at Kennedy News and Media, writing stories for national newspapers, websites and magazines. Now working as a freelancer, he divides his time between teaching at News Associates and writing for news sites on all subjects.