Time travel used to be the thought of science fiction movies and TV shows like the popular show Dr. Who. Real scientists however have something different to say and it goes back to the days of Albert Einstein.

Einstein’s Theory of Time Dilation

Einstein was a brilliant man in the nineteenth and twentieth centuries, well beyond his time in science. He published many famous theories including one that is known as time dilation. The basic definition of Time dilation is simply:

“An actual difference of elapsed time between two events as measured by observers either moving relative to each other or differently situated from gravitational masses.”

With our recent start into low orbit space travel and deep space exploration, scientists have observed a few examples of this exact definition, proving that at least one type of time travel is actually possible. Travelling into the future.

Though, this isn’t the type of time travel where people jump into a DeLorean or other type of time machine and can travel back and forth at will in seconds. Nor is it proof that people from the future are visiting us right now like this. It takes time, and you need to leave the planet.

t = t₀/(1-v²/c²)^1/2

Occurrences of Time Dilation

Clocks on the International Space Station (ISS) run slightly slower than the clocks here on Earth. In fact, astronauts that spend six months on the ISS are 0.007 seconds younger than their counterparts on Earth. This may not seem like a big difference, but it depends on the speed in which you are travelling. If, instead of travelling at 4.791 miles/s the speed of the ISS, you were travelling closer to the speed of light, you could age just a few weeks and when you returned from  space people on Earth would be years older. Essentially travelling through time into the future.

Russian engineer and cosmonaut Sergei Avdeyev held the record for time travel at travelling 0.02 seconds into the future by spending 747 days aboard Mir travelling at a speed of 27,360 km/h. We now know that travelling into the future is possible and has been proven.

While this may seem like an amazing feet, it has its down sides as well. Picture a group of men head out to a distant planet at great speeds for scientific study as we do with probes now. When the group returns, depending the time and speed they travelled at, there friends and family may be gone or greatly aged.