Travelling Through Time

Star trails captured by Samar

From an infant to a scientist, everyone has thought about the possibility of time travel. To go back into the past and change the things done to face different consequences or travel into the future to see how it looks.

Time travel means to move between different points in time.

Hypothetically, say you could see the future. Hence, you would want to change it if you are not content with it. But here is the catch- what if-“Every time you look at the future, it changes; because you looked at it”?

What if it is not the same anymore, because you looked at it. What if nature never allows for this to happen? What if you see something, you are not supposed to see — the future, your future, our future. Is it true that some things which are beyond our imagination are to be kept secret and to be open only when the time comes?

Here’s an interesting term- time. What is time, anyway?

When someone asks you the time, you might say, its 8’ o clock or 5 minutes past noon, but how do we actually describe time? And even if we do, is that the real meaning of time? Because ‘time’, is a word we made up on our own to describe but is time even real?

While most people think of time as a constant, physicist Albert Einstein showed that time is an illusion; it is relative — it can vary for different observers depending on their speed through space. To locate anything in space, we use 3-Dimensions (length, breadth, height). And we call an illusion as the fourth dimension that is time. This fourth dimension provides the direction, although conventionally it only moves forward.

But if it moves, and it moves forward, then can we oppose its direction to go backwards, back in time? Back in an illusion? To the past?

The grandfather paradox is a potential logical problem that would arise if a person were to travel to the past time. The name comes from the idea that if a person travels to a time before their grandfather had children, and kill him, it would make their own birth impossible. So, if time travel is possible, it somehow must avoid such a contradiction. The thing is that contradictions such as the grandfather paradox don’t necessarily mean that time travel is impossible. An extraordinary thing like time would require more than just logically consistent arguments and paradoxes to rule out the possibility of time travel.

Technically, we are travelling back in time. Every time you look at the stars, you are looking back into the past; the apparent position of the stars would have changed as it takes time for the light from the stars to reach our eyes. But this isn’t the time travel we want to experience. We want time travel like in ‘Back to the future’ or ‘Star Trek’ or ‘Doctor Who’ or ‘Harry Potter’ or ‘Chilling Adventures of Sabrina’.

Researchers and scientists say that we know just about 5% of the universe and 95% is still unknown. With this little amount of knowledge, have we figured out ways that could be theoretically possible to achieve? So that we could time travel?

Astronomer Frank Tipler proposed a mechanism known as a Tipler Cylinder, where one would take a matter which is ten times the mass of the Sun, then roll it into a very long and dense cylinder. After spinning this up a few billion revolutions per minute, a spaceship nearby that follows a very precise spiral around this cylinder could get itself on a “closed, time-like curve”. The cylinder needs to be infinitely long for this to work. Another possible method would be to move a ship rapidly around a black hole or, artificially create that condition with a large, rotating structure. The crew would need to travel around the speed of light for this to work. Around and around they would go, experiencing just half the time of everyone far away from the black hole. The ship and its crew would be travelling through time, as suggested by Stephen Hawking.

Another theory for potential time travellers involves something called cosmic strings — narrow tubes of energy stretched across the entire length of the ever-expanding universe. These thin regions- leftover from the early cosmos, are predicted to contain a huge amount of mass and therefore could warp the space-time around them. Cosmic strings are either infinite or, they are in loops with no ends, scientists say. The approach of two such strings, parallel to each other, would bend space-time so vigorously and in such a particular configuration that might make time travel possible, in theory.

Some things might indeed seem impossible, but even ‘impossible’ says ‘I m possible’, right?

There is so much more to what we know. There are things and strings we cannot see. There exist reality and illusions that are so hard to differentiate. Perhaps, what we know is not the truth, and maybe it’s not false either. Maybe, it’s just a part of something huge; something we cannot quite understand yet, hence it is incomplete. What makes the universe more interesting is that it is so vast, and there are still so many things longing to be discovered. Life on Earth is 4.5 billion years old, and we have estimated to know just about 5% of the cosmos. Maybe even less! Hopefully, one day we will satisfy our existence when we fully comprehend what the universe is all about. Maybe one day someone will ask us “What’s the time?”, and we will reply without looking at the watch.

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