By Juliano Oliveira
An undergraduate student of the University of Queensland (UQ) has determined that paradox-free time travel is theoretically possible.
The fourth-year Bachelor of Advanced Science (Honours) student Germain Tobar has reached this result through mathematical modelling, under the supervision of UQ physicist Dr Fabio Costa.
Both physicists affirmed to have found a way to “square the numbers” in which the calculations may bring fascinating outcomes for science.
“The maths checks out – and the results are the stuff of science fiction,” Dr Costa said.
“Say you travelled 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.”
Mr Tobar explains that classical dynamics says if we 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.
“For example, if I know the current position and velocity of an object falling under the force of gravity, I can calculate where it will be at any time.
“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.”
Named as “the holy grail of physics” by Mr Tobar, the unified theory that could reconcile both traditional dynamics and Einstein’s Theory of Relativity has been studied by scientists for decades.
“But the current science says both theories cannot both be true,” he 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.
“I wondered: “is time travel mathematically possible?”
Stopping COVID-19
“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,” Mr Tobar said.
“No matter what you did, the salient events would just recalibrate around you.
“This would mean that – no matter your actions – the pandemic would occur, giving your younger self the motivation to go back and stop it.
“Try as you might create a paradox, the events will always adjust themselves, to avoid any inconsistency.
“The range of mathematical processes we discovered show that time travel with free will is logically possible in our universe without any paradox.”
The research was published in Classical and Quantum Gravity (DOI: 10.1088/1361-6382/aba4bc).