If you always dreamed of building a time machine for changing some of your past mistakes, you must know that it’s not entirely impossible. If we humans perceive time flowing into a single direction, the truth is that it can also run backward.
Albert Einstein predicted about a century ago that it’s entirely possible to travel back and forward in time, at least in theory. Thanks to his genius mind and fabulous curiosity, the renowned physicist offered us at least three ways of performing time travel.
Surpassing the speed of light
Einstein said that nothing should be able to surpass the speed of light, but if it somehow does, that object can go backward in time. Once a massive object achieves the speed of light, its mass becomes infinite. This obviously means that surpassing an infinite mass is contrary to both common sense and the laws of physics themselves. But the Universe can do a pretty good job at defying the laws of physics if it wants to. Black holes are a good example for that manner.
Einstein calculated that if an object ever surpasses the speed of light, it can make time run in reverse. For the moment, nobody created a spaceship capable of flying that fast, but it’s sure worth trying in the far future. A cosmic journey close to the speed of light can also mean other unwanted scenarios that include time dilation. According to the Theory of General Relativity also postulated by Albert Einstein, time would run much slower for the one flying with a speed close to the speed of light. This means that while for the pilot the journey lasted for half an hour, he would see people older by several decades once he returns to Earth.
Jumping into a black hole
A black hole’s gravity exceeds human comprehension, which means that the odds for landing on one alive are very low. But maybe with some special kind of equipment in the far future, we’ll be able to do it. While the most probable scenario is that nothing can survive falling into a black hole, Einstein’s equations give us a glimpse of hope. The renowned physicist claims that there’s at least a theoretical and slight chance that being sucked in by a black hole can actually lead you back in time. Of course, it may not be worth taking the risk, but it’s still one of the best chances we have for time travel at this point.
Using different gravity
This one can allow us to travel to the future much faster, and it’s even far less dangerous than the other two methods. The stronger the gravity is, the slower you’ll advance through time. This means that an hour spent on a bigger planet can mean a year spent on Earth. When you’ll return home from that planet after spending many hours there, all your friends, family, and foes will be older with several years. And the best part is that you won’t feel time running slower at all. This method is also resulting from Einstein’s Theory of General Relativity. Of course, the only problem is that we have to find a way to arrive on another planet. For the moment, humanity had never done it.
However, we cannot be sure that traveling back in time might really change history as we want, or it will just make some changes for another timeline from a parallel Universe. But at least we now know the right formula for time travel and see what the outcome will be if we’ll be willing to take the risks. We’ll also have to wait for science to evolve much further. For the moment, the Universe’s laws are merciless with all of us, and they don’t seem to care about our desires.
From a slightly philosophical perspective, we’re all time travelers. We’re advancing through time and towards the future with every day, hour, second, and so on.