People on Mars will see time passing differently from Earth

When flying to Mars, astronauts will experience time dilation. This was predicted before. In fact, human feet and heads also experience time dilation right here on Earth: the head ages a little faster than the feet. But how much time dilation will Martian astronauts experience compared to Earthlings?

The rate at which time passes is different for each observer, depending on their relative speed, distance from the gravitational field, and the strength of that gravitational field. Time dilation is the difference between the passage of time on two clocks due to these causes, as described by Albert Einstein’s special and general theories of relativity.

Gravity warps space-time. As a result, the stronger the gravitational force is near the observer, and the closer he is to the mass that produces it, the slower time will flow from the perspective of another observer – the one with the second watch. From the perspective of the original observer, time passes at a normal speed.

This is why the feet are “younger” than the head. The farther you are from Earth’s gravity – for example, working on top of a skyscraper – the more pronounced the time dilation effect becomes compared to observers on the ground. However, this is not a large effect, only a tiny fraction of a nanosecond per year.

For astronauts living in a weightless environment for long periods of time, this effect is more pronounced, but is eliminated by the speed at which they move. “Because astronauts and satellites orbit the Earth a little farther from the center of the planet than people on the ground, they experience less gravitational time dilation. This causes astronaut time to elapse. astronauts should have flowed faster,” astronomer Colin Stuart explained.

“But in reality, this effect is quite small because the Earth’s gravity is quite weak. So the time dilation effect due to speed dominates,” Stuart added. This causes astronauts to age more slowly. For example, Russian astronaut Sergei Krikalev – who spent a total of 803 days, 9 hours and 39 minutes in space – is 0.02 seconds younger than people on Earth.

Reaching Mars on a 21-month round-trip flight, astronauts will experience a slight time dilation effect. From their perspective, time passes normally, but to an observer on Earth, the difference can be a few nanoseconds. Although the speed of a Martian astronaut will be faster than any human in history, compared to the speed of light, which has an extremely obvious time dilation effect, this speed is still small.

If astronauts stay on Mars for a long time, the gravitational time dilation effect will become larger. According to the Physics Van program of the University of Illinois at Urbana – Champaign, a person who lives 80 years on Mars will die about 12 seconds sooner than a person who lives 80 years on Earth. But from their perspective, they won’t feel it.