Sushiksha

Introduction

No time travel talk would go without our geek, Einstien. In 1905, Einstein published the first part of his relativity theory known as special relativity. This shows that particles of light travel through a vacuum at a constant pace of approximately 3,000,00km/s, How insane is that? A speed that's immensely difficult to realize and impossible to surpass in that environment. Yet all across space from black holes, particles are in fact being accelerated to incredible speeds some even reaching 99.9% of the speed of light. Let me not bombard you with a lot of scientific terms and facts. Getting straight to the point, Is traveling to our future or past really possible?

 🚀 Travelling to the Past!

Imagine you magically obtain watch that let's you travel back and forth in time. One day, you get an idea to travel back to the 90's to meet your ancestors. You press a few buttons, and suddenly you're standing beside your young grandpa in his 20's under medication in a hospital. Since you've never been the biggest fan of your grandpa, you decide to take off his breathing support (let's just assume haha!). Ventilator does its thing, and a few seconds later, no more Grandpa. But wait, if you killed your grandpa before he ever met your grandma, you would not have been born to be able to return in time and kill him! Here's the problem. If you didn't exist, you couldn't have killed him. Because you didn't kill him, he's still alive. But that would mean that you yourself would be alive and now you can go back in time to kill him. And so the endless loop goes on. This is called the Grandfather Paradox. And this is one of those things that make time travel so interesting.

If, infact considering the casualities and paradoxes, then we have our answer, time travel to the past is impossible. If however, the Novikov Principle is correct, then there is still a possibility. The principle states that if an event exists that would cause a paradox, then the probability of that event is zero. It means that it will be impossible to create time paradoxes. Unfortunately, considering most of the scientists, this Principle is not widely accepted. The science behind time travel to the past, is much more complex to understand. Scientists still point out the possibilities using wormholes which are a lot more complex to understand.

 🚀 Travelling to the Future!

The grandfather paradox which we discussed in previous section deals with time travel on a significant scale. But why don't we start with something a little smaller? Remember our time travel watch? Let's assume me and you are wearing identical watches and we sync them right before I blast off into space. In the space shuttle, I'm traveling at roughly 28,000 kms/h relative to the Earth. If I make a few orbits around the Earth before I return, when we compare watches, we'll see that less time has passed for me. A very tiny amount of time, but it is there nonetheless. This is called Time Dilation. Try calculating it yourself using Time Dilation calculator.

The strangest aspect of relativity is in direction of motion, the distances shrink. When we think of traveling to a point 10 light years away at 90% of light speed,you'd expect it to take 11 years, right? thats not excatly the case. To a stationary observer, it would seem to take your shuttle 11 years. But to the people inside the shuttle, not only time, but distance would dilate and you would reach that point in only 4.4 years. Okay, that's all really cool and interesting, but is it really time travel? Actually not in the sense that we generally think of it, but it is time travel according to the nature of space-time. If you were to return home from your 90% light speed trip, you would be almost 9 years older. But everyone back on Earth would have been 22 years old. So in reality, you've traveled 13 years into the future relative to your time in space. You might have observed this on the popular movie Interstellar, 1 hour on the planet was equal to 7 years aboard the shuttle. When Cooper & team makes it back to the shuttle after a little over three of their hours, their friend had aged by 23 years. The craziest thing is that this isn't just science fiction. Those calculations all check out. That's exactly how it would happen in our real life. So in essence, cooper & the team had traveled 23 years into the future.

Conclusion

It all leaves us with just assumptions of possible realities. For now, Time travel is something which we can create theories on but feels far from reality. But who knows, maybe someone from the far future will show up in our time and give us the key to unlocking the mystery or would that create yet another paradox?