The Time Traveler Cosmonaut The greatest time traveler to date is Sergei Krikalev, a cosmonaut who spent more than 803 days in low-Earth orbit, traveling at high speed, and thus has aged 1/48th of a second less than he would have if he had stayed home. When he returned to Earth, he found the Earth to be 1/48th of a second to the future of where he expected it to be. So he has time-traveled 1/48th of a second into the future. If you were to fly out to the star Betelgeuse, 500 light-years away, at 99.995 percent of the speed of light and then return at the same speed, the Earth would be 1,000 years older when you got back, but you would only have aged 10 years. Credit: Heather Wax

The Time Traveler Cosmonaut

The greatest time traveler to date is Sergei Krikalev, a cosmonaut who spent more than 803 days in low-Earth orbit, traveling at high speed, and thus has aged 1/48th of a second less than he would have if he had stayed home. When he returned to Earth, he found the Earth to be 1/48th of a second to the future of where he expected it to be. So he has time-traveled 1/48th of a second into the future. If you were to fly out to the star Betelgeuse, 500 light-years away, at 99.995 percent of the speed of light and then return at the same speed, the Earth would be 1,000 years older when you got back, but you would only have aged 10 years.

Credit: Heather Wax