Time travel is possible, but it’s a one-way ticket

Time travel is possible, but it’s a one-way ticket

What is Time travel? 

In simple words, Time travel is the idea of going back in time to the past or forward to the future. We always travel forward, to the future. Time travel to the past is not known to be possible(till now), but it is much used in fiction.

Is Time Travel possible?

The power to travel through time, whether it is to repair a mistake in the past or increase insight into the future, has long been taken in science fiction and argued by theoretical physicists. While the discussion continues over whether travelling into the past is logical, physicists have deduced that travelling to the future most clearly is. And you don’t require a wormhole or a DeLorean to do it.

Real-life time travel exists through time dilation, a property of Einstein’s special relativity. Einstein was the first to discover that time is not constant, as lately believed, but rather slows down as you move faster through space.

As part of his theory, Einstein reimagined space itself. He originated the phrase “spacetime,” blending the three dimensions of space and one dimension of time into a single term. Instead of dealing with space as a flat and rigid place that carries all the objects in the universe, Einstein belief of it as curved and flexible, able to build gravitational dips around masses that pull other objects in, almost as a bowling ball placed in the centre of a trampoline would affect any smaller object positioned on the trampoline to slide towards the centre.

The nearer an object gets to the centre of the dip, the quickly it accelerates. The centre of the Earth’s gravitational dip is fixed at the Earth’s core, where gravitational acceleration is powerful. According to Einstein’s theory, because time motions more slowly as you run faster through space, the closer an object is to the centre of the Earth, the slower time actions for that object.

Proof of Time Travel in daily life

This impact can be observed in GPS satellites, which circle 20,200 kilometres above the Earth’s surface. These satellites have highly detailed clocks onboard that increase an average of 38 microseconds per day because of time dilation. While this time gain appears insignificant, GPS satellites rely on their onboard clocks to retain precise global positioning. Running 38 microseconds fast would conclude in a positioning error of approximately 10 kilometres, an error that would increase every day if the time difference were not constantly regulated.

Time dilation in movies

A better dramatic example of time dilation can be glimpsed in one of the best sci-fi movie Interstellar when Matthew McConaughey and his team land on a planet with a drastic gravitational field affected by a nearby black hole. 

Because of the black hole’s serious gravitational influence, time slows dramatically for the team on the planet, creating one hour on the surface equal to seven years on Earth. This is why, when the squad returns to Earth, Matthew McConaughey’s daughter is an old woman while he seems to be a similar age as when he left.

So What’s the Problem in Time Travelling?

The reason why humanity hasn’t achieved making such tough leaps forward in time appears down to velocity. For humanity to transmit traveller years into the future, we would either have to receive the benefit of the intense gravitational acceleration influenced by black holes or send the traveller rocketing into space at almost the speed of light (about 1 billion km/h). With our existing technology, leaping a few microseconds into the future is all humans can regulate.

What about Time travelling to Past?

But if technology one day enables us to transport a human into the future by travelling near to the speed of light, would there be any means for the traveller to use time dilation to return to the past and report his/her findings? “Interstellar voyage reaching near to the speed of light might be possible,” says Dr Jaymie Matthews, professor of astrophysics at the University of British Columbia, “[but] this journey is one way – into the future, not back to the past.”

If we can’t utilize time dilation to come back to the past, does this tell that the past is forever inapproachable? Possibly not.

The Time Travelling Machine

Einstein formulated that time travel into the past could be attained through an Einstein-Rosen bridge, a sort of wormhole. Wormholes are suppositional areas of spacetime that are curved in a way that binds two distant points in space.

Einstein’s equations indicated that this bridge in space could hypothetically bind two junctures in time instead of if it were strong enough. “At the period, even an Einstein-Rosen bridge cannot [be used to] go back in the past because it doesn’t exist long sufficiently – it is not stable,” Matthews explains.

“Even if it was strong, it [requires] additional physics, which we don’t have. Theoretical particles and states of matter that have “exotic” physical properties that would corrupt known laws of physics, such as a particle possessing a negative mass. That is the reason why “wormholes” are just science fiction.”

Movies questioning Paradoxes of time travelling

While it would be amusing to travel back in time to watch the dinosaurs or to meet Albert Einstein and demonstrate to him the existence of time travel, maybe it is best if the past continues untouched. Travelling to the past brings on the possibility of giving rise to a change that could demolish the future. For example, in Back to the Future, Marty McFly tours to the past and inadvertently saves his parents from meeting each other, almost preventing his presence. But if he had undone his reality, how could he have gone back in time in the first place?

Marty’s adventures are an alternative to the grandfather paradox: what occurs if you go past in time and murder your grandfather before your father is born? If you are successful, how is it reasonable that you’re existing to kill your grandfather in the first place?

More movies that show time travel in various ways and their paradoxes can be observed in movies like Source Code, Predestination, Stein’s Gate(web series), Looper, Edge of tomorrow or Avengers: Endgame and many more.

The Ultimate Solution

A new study at the University of Queensland may have the explanation for this baffling contradiction. In this research, the researchers prove mathematically that paradox-free time travel is practical, indicating that the universe will self-correct to resist inconsistencies. If this is true, then even if we could roam back in time, we would never be eligible to distort events to establish a different future.

While these new outcomes are enlightening, there seems to be more indication that, although time dilation can enable us to peek into the future, we will never be skilled to visit the past. As the late Stephen Hawking said in his book Black Holes and Baby Universes, “The best proof we have that time travel [into the past] is not possible, and never will be, is that we have not been invaded by hordes of tourists from the future.”

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