Russian cosmonaut Sergei Krikalev has spent more time in orbit around the Earth than anyone - 803 days, 9 hours and 39 minutes.
And thanks to Universe Today, we now know another interesting fact about the retired Russian space adventurer…
He's also the world's most prolific time traveller.
Universe Today points out that due to the effects of time dilation, Krikalev has actually lived for 0.02 seconds less than everyone else on Earth - effectively, he's travelled 0.02 seconds into his own future.
The calculation relies on Einstein's theories of relativity, which state that the passage of time is relative, and different, for two objects moving at different speeds or experiencing different levels of gravity.
But don't let the word 'theory' fool you - dilation is a real effect, and has been demonstrated in experiments conducted first by flying highly accurate atomic clocks around the world on jet aircraft, and later by GPS satellites which have to be reprogrammed daily to counter the effect.
Every astronaut in orbit around the Earth will undergo some level of dilation, since they are travelling at such great speed (7.71 km/s in the International Space Station) for long periods.
Still the amount of dilation is very small - just fractions of a second. But if you work out the maths, Krikalev has gone further than anyone else for a combined 0.02 seconds of time travel. A small step, perhaps. But in some ways a pretty amazing one.
Check out the full story over at Universe Today.