It seemed to exist only in theory and science fiction stories, but it turns out that someone has experienced the sensation of time travel.
Science has previously demonstrated that time travel is possible—at least in theory. According to Albert Einstein’s theory, if we reach or approach the speed of light (300,000 km/s), we can travel to the future.
We can perform time travel – at least theoretically.
According to Professor Brian Greene, a theoretical physicist at Columbia University: “You can create a spaceship, go out into space, and travel at the speed of light, then turn around and come back to Earth.”
“Imagine, you take six months to travel, then return in another six months.”
During that time, your personal time will pass more quickly while those on Earth remain unchanged. This means you have traveled very fast while real time remains slow.
Reaching the speed of light is impossible, or at least not achievable at this time.
“When you step out of the spaceship, you will have aged one year, but Earth will have passed many, many years. You could go to the future 10,000 years, 100,000 years, or even a million years, depending on how close to the speed of light you travel.”
Of course, reaching the speed of light is impossible, or at least not achievable at this time. To reach that speed would require an energy source so vast that it is “unimaginable”—in Greene’s words. Moreover, the centrifugal force generated at such speeds would surely turn your body into mush.
Additionally, there is another way to time travel: by positioning oneself at the edge of a black hole. The immense gravitational force of a black hole is enough to warp spacetime, causing time to slow down. The outcome is the same—you move towards the future, but this method is also not feasible at this moment.
The immense gravitational force of a black hole is sufficient to warp spacetime.
But time travel has actually occurred
The person who experienced it is Sergei Krikalev, a Russian astronaut who currently holds the record for the longest time spent in space: 803 days, 9 hours, and 39 minutes.
Specifically, Krikalev spent this time aboard the International Space Station (ISS) over six missions. The record was set on October 11, 2005.
The ISS moves at a speed of 7,660 m/s in orbit around Earth. This speed is sufficient to exceed Earth’s time rate through a process known as “time dilation”, allowing Krikalev to travel into the future.
Sergei Krikalev – the astronaut with the longest time in space in history.
However, the future that Krikalev experienced was a mere… 0.02 seconds.
According to Colin Stuart, a physicist and prominent TED speaker, this negligible time dilation occurs because “Earth’s gravitational force is too weak, so the time dilation caused by the ISS’s speed is very small, and the astronaut only really travels into the immediate future for a very brief moment.”
Stuart argues that this proves time travel to the future is indeed possible. However, traveling back into the past presents a different challenge.
Even if it is only 0.02 seconds, Krikalev has truly reached the future.
“No one has truly proven that we cannot travel back in time”—quoting Professor Greene.
“But whenever there is a suggestion about time travel to the past, it exceeds our understanding within current physical theories.”
“Moreover, most experts feel that even as physics advances, time travel to the past will likely never occur.”
