I’ve seen the future and I’m not going.”

That’s the title of a very popular memoir of the life of artist David McDermot. Now, on the other hand, Russian cosmonaut Sergei Krikale had no other choice but to travel into his future.

Krikalev holds the record for most time spent in orbit around the Earth at 803 days. Because he spent so much time in space away from Earth’s center of gravity, time dilation [or the slowing down of clocks] caused Krikalev to be 0.02 seconds younger than other people born at the same time as him.

He is the only man who has ever time traveled.

A Quick Explanation of How Time Travel Works

Einstein’s Theory of Special Relativity is based on two basic principles.

One is that the laws of physics don’t change, even when objects move at constant speeds to each other. In other words, the speed of light is a fundamental constant.

The other principle is that the speed of light is the same for everyone, no matter how they move in relationship to the light source.

*This guide explains more if you’re interested.

In order to time travel, engineers would have to build a space ship that could travel at the speed of light (186,000 miles-per-second), and head out into space.

Einstein once wrote: People like us who believe in physics know that the distinction between past, present, and future is only a stubbornly persistent illusion. Time, in other words, he said, is an illusion.

“If you go fast, your clock runs slow, relative to people who are still,” says physicist Bryan Cox. “As you approach the speed of light, your clock runs so slow you could come back 10,000 years in the future.”

Even when an astronaut comes back to Earth, they have gone into the future slightly and catch up with clocks on the ground.

The effect of time dilation, however, “is quite small because Earth’s gravity is quite weak,” says educator Colin Stuart in this informative instructional video from TedEd, “and so the time dilation due to their speed wins out and astronauts really do travel a tiny amount into their futures.”

Awesome! Now that you’re an expert physicist let’s get on with the rest of the story.

The Soviet Union Forgot Him in Space for 311 Days

When the Soviet Union dissolved they left Sergei Krikalev in space for 311 days. The country that sent him to space no longer existed, so he stayed in space twice as long as the mission originally called for.

Interestingly enough, that wouldn’t be enough to deter him from space travel as he wouldn’t retire from space flight until 2007.

“Space can be fun, depending on who you are with” — Sergei Krikalev

When astronauts and satellites orbit the Earth, they are slightly further away from the center of the planet, and so they actually experience less gravitational time dilation.

This means the astronauts’ time would run slightly faster, and when they return to Earth, they’d have to “come back” to the past, even if it’s only a few microseconds.

The International space station travels at around 17,130 mph when orbiting around Earth. Because Kriikalev has spent more time in space than any other human who ever existed, he returned to Earth 0.02 seconds into the future.

Is it enough to make him as cool as Bill and Ted, or Marty McFly? Only time will tell.