There is probably an unbelievably long list of the challenges that human astronauts would face in the event of a manned mission to Mars.

Dealing with time dilation is definitely on the list.

We all experience time dilation to some degree. Time passes at different rates for different observers, depending on their relative speeds and their proximity to (and strength of) nearby gravitational fields.

Your head and your feet technically experience time differently, making your head slightly older than your toes.

Weird, right?

Time dilation is the difference between time elapsed on two clocks depending on their special relativity and general relativity.

Because of the way gravity curves spacetime, gravity is stronger near you, and the closer you move to the mass creating gravity, the slower time moves.

The further you get away from Earth’s gravity – like, if you’re on top of a tall building – the more pronounced the effect compared to those on the ground.

Not a lot in that example; a fraction of a nanosecond a year.

It is much more pronounced for astronauts experiencing zero-gravity for long periods of time.

That said, astronomer Colin Stuart says it’s almost canceled out by the speed at which they travel through space.

“Because astronauts and satellites orbiting the Earth are slightly further away from the centre of the planet (compared to people on the ground) they actually experience less gravitational time dilation. O its own this would mean astronauts’ time would run faster. However, this effect is quite small because Earth’s gravity is quite weak and so the time dilation due to their speed wins out and astronauts really do travel a tiny amount into the future.”

When Cosmonaut Sergei Krikalev was stranded in space for 311 days, he technically traveled 0.02 seconds into the future.

A trip to Mars would take around 21 months, roundtrip. The astronauts will experience time passing normally, but it will actually be a few nanoseconds difference from how we experience life on Earth.

If they stayed on Mars for extended periods of time, the effects of gravitational time dilation could be enough to be noticeable.

For example, if you lived 80 years on Mars, you would pass away 12 seconds earlier than if you passed away after exactly 80 years on Earth.

From the point-of-view of the person experiencing either end, though, it would feel exactly the same.

Spacetime is wild, y’all.

I have a feeling we’re going to have the opportunity to study it more in depth very soon.