Time travel which means traversing between various points in time — has been popular science fiction fodder for years. Multiple attempts have been made in Hollywood, where we have seen humanity get in a machine and travel forward or backwards in time. There are various theories about time travel. But will time travel ever be possible?
However, the reality is more complicated than the movies. Not all scientists render time travel possible. If any attempt is made, it would be deadly for the subject to experiment with it to make time travel possible.
Does Time Travel Exist?
Before we attempt to unravel this mystery, we need to decipher what time is. Most people assume that time is constant, correct in all philosophical terms, but one physicist thought otherwise. Albert Einstein displayed that time is mostly an illusion, which means it is very relative. It may vary for different independent observers who will be dependent on the speed through space. According to Albert Einstein, there is a “fourth dimension,” which is perceived as time. The three-dimensions are constrained in space. It provides a time traveller with coordinates that show the three-dimensional location. Time offers a fourth dimension that is direction — which according to conventional theorems, only moves forward. Relativity theory denotes the fluctuation of time with respect to an object. Also, according to Einstein’s general relativity theorem, gravity too can bend time. These factors do make us wonder could time travel be possible.
Let us imagine a four-dimensional piece of cloth called space-time. When anything that has mass is placed on that cloth, it causes a strain or an inward bending of the space-time. This bending would force any object which wants to move across to go on a curved path. This curvature of the course is known as gravity. So herein, some general instances of experiments with time travel have been done. Both the relativity theories have been validated with Global Positioning System satellites that carry pinpoint precise timepieces on the spaceship. Gravity and increased relative speed of the satellites make the unadjusted watches gain approximately 38 microseconds a day. So in some way, the astronauts are time travellers as they return to earth younger slightly than that of their identical twins who are on the planet. This effect is known as time dilation. This is one way we can say or consider time travel is possible.
What is a Time Traveller?
The general theorem of relativity gives us depictions that could allow a person to travel across time and be called a time traveller. However, those equations, even though theoretically possible they might be a little difficult to achieve physically. The possibility that is being talked about is if one could travel faster than the velocity of light, which is 186,282 miles per second in a vacuum, only then can the person be sent to the past or future. However, Albert Einstein’s equation also theorizes that any object that achieves light’s speed would have an infinite mass and zero length. Is that even possible practically!!! Some scientists say it can be done.
Once it is possible to make an object of infinite mass and zero-length, we can answer whether time travel will ever be possible?
We might get our best shot by starting to build a time-travelling spaceship, but the engineering hurdles, at least in 2021, are enormous. Firstly, we are not remotely adjacent to have a spacecraft that can reach the velocity of light. The fastest spacecraft that is ever made; will be set in motion this summer, the Parker Solar Probe. Guess what? It would travel only at .00067 per cent the speed of light.
There is also a requirement of enormous amounts of energy needed for highly efficient antimatter fuel. Scientists suggest that antimatter fuel which is highly efficient could be the key and would also be the missing piece to interstellar travel.
It is also necessary to ensure the human capsule’s safety on such a time-travelling mission, and it would be very tricky. First and foremost, the ship needs to carry ample supplies for survival for the entire journey and make time travel possible.
We also need to make sure the stupendous g-force wouldn’t disintegrate our hypothetical time traveller; the ship would need to accelerate moderately. The acceleration that we undergo on Earth is stable, and for an extended period, it would ultimately get the vessel to approach near the speed of light. It would also add to the trip’s length and provide constraints to how far in the future one could travel.
Alternate theorems of Time Travel
A mechanism was proposed, namely known as Infinite Cylinder. An object ten times the sun’s mass would be taken and rolled into an infinitely long dense cylinder. This, when revolved for a billion revolutions a minute, a spaceship following a precise spiral around the cylinder could get into a time-like curve. This is just a theory; it sounds outrageous!!
Another way of making time travel possible is to move a ship with an extreme velocity around a black hole or create an artificial machine like the same with a vast structure rotating. According to Stephen Hawking, they would be travelling through time. However, they have to travel at the speed of light for years to make time travel possible. Another limitation is that the movement would be centrifugal and make the machine extremely unstable to the extent that it would break down. To make time travel possible, via building a time machine, it is often suggested to use an un-naturalized form of matter having an energy density in negative. Such matter has unique properties, including moving in the contrasting direction of the ordinary matter when pushed. Such cases could have a theoretical existence, but they might be present only in too minute amounts to construct a time-travelling machine if it does have any presence. The first and foremost thing to be done is to get a circular-shaped hollow shape sheathed within a sphere of non-exotic matter. The gravitational fields come into play as they try to form a time-like curve, which remains closed.
In order to revisit the past, the traveller needs to dive inside the Eigen-shaped structure, which allows him to reconceive the past with simultaneous rotations.
Grandfather Paradox
Time travel has its unique problems, and physics is not the only one here. A paradox that generates an alternate reality when we go back in time to alter events that leads to time travel is a very tricky situation that scientists haven’t given a reason for yet.
When will Time Travel be possible?
While time travel does not appear feasible for the time being — at least, likely in the concept that humans would survive time travel — with the physics currently in use today, the field is continually changing—advances in quantum theories the future could perhaps explain how to overcome the paradoxes of time travel and physics hurdles. However, in the meantime, wanna-be time travellers can experience it through sci-fi movies, television, and books.
