Hello McFly: Time Travel Is Theoretically Possible, Physicists Say They Did The Math To Prove It

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The concept of Time travel often comes up in a multitude of pop culture references, and it gets rather confusing with all the interpretations. If you begin to think about it, paradoxes and loopholes plague our understanding of how it all should work too. After all, it's science fiction is it not?  Based on the math of a University of Queensland Australia undergrad, though, “Paradox-free time travel is theoretically possible,” so suck it pop culture. Could sci-fi again someday become reality?

A fourth-year Bachelor of Advanced Science student, Gemain Tobar, decided to investigate the possibilities of time travel under the guidance of University of Queensland physicist Dr. Fabio Costa. When it comes to time travel, there are two prevailing theories, according to Tobar. “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,” he says. “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.” Based on science, both theories cannot coexist, but the math says otherwise when ultra-smart physicists dig into it. 
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Dr. Fabio Costa And Germain Tobar (Student) University of Queensland

Tobar and Dr. Costa have seemingly found a way in which they “square the numbers” to make the math for time travel check out. In their example with the COVID-19 pandemic, if you were to time travel to stop patient zero from catching COVID-19, common thinking would be that you would stop the pandemic, leading you to not travel back in time, which is a paradox. The researchers' math, however, leads to new thinking in which if you traveled back to the COVID-19 patient zero, the timeline change to end up right back where we are now, but you or someone else would be patient zero. According to Tobar:
“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.”
In the end, time travel without paradoxes is mathematically possible, according to this research report, but you cannot change the future. This sort of explanation harkens to the Hulk’s description of time travel from Avengers Endgame. Though it was confusing initially, with this context in mind, it is a bit more digestible.

This sort of research could open new windows into the possibilities of time travel and relativity, but we're not scientists of any sort here. We'll leave the heavy lifting to trained researchers of course. The concept of time travel is still very complex, but paradoxes may be better understood now, so the concept might be slightly less confusing. If you want to read the paper on the topic, you can do so in Classical and Quantum Gravity here.