Time travel may be possible, but it’s just sad
Time travel is just sad
I’ve always liked the Back to the Future (BTTF) movies - the story lines, the goofy acting, the whole lot. Even the oxymoronic names, like the BTTF title itself; Hill Valley, the fictional town in the series; and “flux capacitor”, the core component in Doc Brown’s time-traveling DeLorean.
While it makes for a great movie idea (see: Twelve Monkeys, The Time Traveler’s Wife, The Lake House, The Terminator, and perhaps hundreds more), time travel is impossible.
Okay, at least not today.
Let's talk theory first. You see, if you managed to get into a super-fast vehicle that's moving near the speed of light, according to the theory of special relativity (and time dilation and whatnot), you’ll be able to travel into the future while aging very little. If you’ve a clock in said vehicle, you'll notice that less time has passed compared to clocks outside the vehicle.
In theory, this means you could, say, enter the vehicle while your child is just born, spend some time in it, and then come out in time to see your grandchildren. (Come to think of it, that’s a terrible idea.)
To take it further, when applied to interstellar space flight, this means that it’s possible to take just a few years to reach a distant planet, though like the previous scenario, it also means that tens, if not hundreds, of years would have already passed on Earth.
(Protip: Make sure you bring your loved ones along for the time travel. Else, you'll be a sad soul when you return.)
While the science behind it sounds solid, we are still a long way off from achieving this. To put things into perspective, in order for space-time travel to be worthwhile (that is, what’s the point of traveling just one second into the future?), an advanced propulsion system is required and that is unlikely to be invented anytime soon.
There are also practical hurdles to overcome. For example, as our vehicle approaches the speed of light, how do we prevent it from colliding with other things, like buildings or space debris?
Some scientists have suggested things like distortions in space-time and worm holes as shortcuts to do time travel, but all these are, again, theories at this stage. In short, we need breakthroughs in many, many, many disciplines before we can start talking about building a time machine.
While it’s still possible to wrap one’s head around the concept of traveling into the future; it’s so much harder to understand how traveling to the past would work. And for so long, physicists and philosophers alike have difficulties resolving the ‘grandfather paradox’.
It basically goes something like this: If you went back to the past to stop your grandparents from meeting, your parents wouldn’t be born, and neither would you. Then how are you able to go back to the past in the first place?
Research conducted by scientists at the University of Queensland recently suggests that time travel, including traveling back in time, isn’t entirely impossible. The caveat? As of now, it’s only possible at a quantum level.
For me, I strongly believe time travel is possible. But as a realist, I also believe it'll take many more generations for it to happen. Since life is short, and tomorrow isn't promised, let's just live in the moment. That’s the happiest way to travel through time, don’t you think?