Paradox-free time travel is theoretically possible

Physicist 'squares the numbers' on time travel.


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.

A unified theory that could accommodate both traditional dynamics and Einstein’s Theory of Relativity was physics’s holy grail.

But the current science says both theories cannot be true. Physicists are keen to understand the Universe’s most basic, underlying laws. For years, they have been puzzled about how the science of dynamics can square with Einstein’s predictions.

Is time travel mathematically possible?

Fourth-year Bachelor of Advanced Science (Honours) student Germain Tobar has been investigating the possibility of time travel under the supervision of UQ physicist Dr. Fabio Costa.

Their study that comes with the mathematical modeling- suggests that paradox-free time travel is theoretically possible.

Mr. Tobar said, “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 modeling how fluids flow.”

In their study, Mr. Tobar and Dr. Costa have discovered a way to “square the numbers.” Their calculations are expected to have fascinating consequences for science.

Dr. Costa said, “Say you traveled in time, in an attempt to stop COVID-19’s patient zero from being exposed to the virus. However, if you stopped that individual from becoming infected—that would eliminate the motivation for you to go back and stop the pandemic in the first place.”

“This is a paradox—an inconsistency that often leads people to think that time travel cannot occur in our universe.”

“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.”

This study has shown that neither of these conditions has to be the case. It also suggests the possibility of events to adjust themselves to be logically consistent with any action that the time traveler makes.

Mr. Tobar said, “The range of mathematical processes we discovered show that time travel with free will is logically possible in our universe without any paradox.”

Journal Reference:

  1. Germain Tobar et al., Reversible dynamics with closed time-like curves and freedom of choice, Classical and Quantum Gravity (2020). DOI: 10.1088/1361-6382/aba4bc