The study says that time travel is possible but not to change the past


  • According to new calculations by researchers at the University of Queensland, time travel is possible based on the laws of physics.
  • But time-travelers will not be able to change the past in a mediocre way, he says – the future will remain the same.
  • For more stories visit the Business Insider homepage.

Imagine that you could press a button in the time machine, and travel back in 2019, before the new coronovirus made the leap from animals to humans.

What if you could find and separate the patient from zero? Theoretically, there won’t be an epidemic, right?

Absolutely not, because then the future — you might not have decided to travel for the first time.

For decades, physicists have been studying and debating versions of this paradox: If we can travel back in time and change the past, what will happen to the future?

A new study provides a possible answer: nothing.

Jermaine Tobar, the study’s author and a student at the University of Queensland, quoted IFLScience as saying, “Anything can happen that events can cause a contradiction, so there is no contradiction.”

His work, published in the journal Classical and Quantum Gravity last week, suggests that according to the laws of theoretical physics, anything you tried to change in the past will be corrected by subsequent events.

Simply put: It is theoretically possible to go back in time, but you cannot change history.

China Wuhan Travel Silent

People in Beijing pay tribute to China’s coronavirus victims on April 4, 2020, during a national moment of silence.

Thomas Peter / Reuters


Dada Paradox

Physicists have considered time travel as theoretically possible since Einstein came up with his theory of relativity. Einstein’s calculations suggest that it is possible for an object in our universe to travel in a circular direction through space and time, ultimately ending at a point on its journey where it has been before – a path that has been closed The time curve is called.

Nevertheless, physicists continue to struggle with scenarios such as the coronovirus example above, in which time-travelers replace events that have occurred before. The most famous example is known as the Dada Paradox: Says a time-traveler goes back to the past and kills a younger version of his grandfather. Grandpa would have no children, erasing time-traveling parents and of course, time-travelers, too. But then who will kill Grandpa?

A film on this paradox appears in “Back to the Future”, when Marty McFly stops his parents from visiting in the past – possibly disappearing themselves.

Time travel dog

A dog dressed as Marty McFly from “Back to the Future” participates in the annual Tomkins Square Halloween Dog Parade on October 24, 2015 in New York City.

Timothy A. Cleary / Getty Images


To address the contradiction, Tobar and his supervisor, Drs. Fabio Costa, then, used the “billiard-ball model”, which imagines cause and effect as a series of colliding billiard balls, and a circular pool table in the form of a closed time-like curve.

Imagine a bunch of billiard balls placed across that circular table. If you push a ball from position X, it collides around the table, hitting others in a particular pattern.

Researchers calculated that even if you mess with the pattern of the ball at some point in your journey, future interactions with other balls may correct its path, which will cause it to return to the same position and speed, which You did not interfere.

“Regardless of choice, the ball will fall in the same place,” said Dr. Berkeley, a theoretical physicist at UC Berkeley. Yasunori Nomura told Business Insider.

Scientists travel time

Fabio Costa (left) with Jermaine Tobar (right). Tobar’s calculations, supervised by Cobra, suggest that time travel is possible without contradictions.

University of Queensland



Tobar’s model, in other words, says that you can travel back in time, but you cannot change how events are revealed to change the future. Applied to the grandfather’s paradox, then, it would mean that something would always be found in an attempt to kill your grandfather. Or at least by the time he died, your grandmother would already be pregnant with him.

Back to the coronavirus example. Suppose you were to travel back in 2019 and interfere with the patient’s life. According to Tobar’s line of thinking, the epidemic will still happen somehow.

“You can try and prevent Patient Void from getting infected, but in doing so you will catch the virus and Patient Void, or someone else will,” Tobar told the University of Queensland.

Nomura stated that although the model is too simple to represent the full range of cause and effect in our universe, it is a good starting point for future practitioners.

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