Physicists at the University of Queensland (UQ) claim to have come up with mathematical modelling that states that it is theoretically possible to go back in time without a paradox.

Prodigious UQ student Germain Tobar has been researching the possibility of time travel, under the supervision of physicist Dr Fabio Costa, according to an official release by UQ.

Tobar and Costa claim to have found a way to “square the numbers” to prove if such time travel is theoretically plausible.

“The math checks out – and the results are the stuff of science fiction,” Dr Costa said.

He further explained an example of a person time travelling to find patient zero of Covid-19 and stop them from getting infected to stop the pandemic. However, this would then eliminate the reason for the person to time travel entirely, creating a paradox.

“This is a paradox – an inconsistency that often leads people to think that time travel cannot occur in our universe,” Dr Costa said.

“Some physicists say it is possible, but logically it’s hard to accept because that would affect our freedom to make any arbitrary action. It would mean you can time travel, but you cannot do anything that would cause a paradox to occur.”

Research findings

However, according to the research, neither of these conditions might be the case. Events are likely to adjust themselves to be logically consistent with any action that the time traveller makes.

“In the coronavirus patient zero example, you might try and stop patient zero from becoming infected, but in doing so you would catch the virus and become patient zero, or someone else would,” Tobar said.

“No matter what you did, the salient events would just recalibrate around you,” he added.

“This would mean that – no matter your actions - the pandemic would occur, giving your younger self the motivation to go back and stop it,” he said.

Tobar has been focusing on whether there can be a unified theory that combines classical dynamics and Einstein’s theory of relativity.

“Classical dynamics says if you know the state of a system at a particular time, this can tell us the entire history of the system. This has a wide range of applications, from allowing us to send rockets to other planets and modelling how fluids flow,” Tobar said.

“However, Einstein's theory of general relativity predicts the existence of time loops or time travel – where an event can be both in the past and future of itself – theoretically turning the study of dynamics on its head,” he said.

Adding that current consensus suggests that both these theories cannot be true, Tobar said, “As physicists, we want to understand the Universe’s most basic, underlying laws and for years I’ve puzzled on how the science of dynamics can square with Einstein’s predictions.”

According to their model, events will align themselves logically to stop any inconsistency in the universe making time travel at free will possible. The research is published in Classical and Quantum Gravity .

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