We all know that Einstein’s theory of relativity permits both forward and backward time travel. But backward time travel is one of the most problematic things with a ton of problems like “grandfathers paradox”. Until now, there is no theory which could make time travel viable without any of these paradoxes.
But, recent research seems to give hope at least in the theoretical possibility of time travel. Physics student Germain Tobar, from the University of Queensland in Australia, says he has worked out how to “square the numbers” to make time travel possible without the paradoxes.
Tobar under the supervision of Professor Fabio Costa has recently published his research in Classical and Quantum Gravity. He claimed that he has mathematically proven the physical feasibility of a specific kind of time travel which used the closed time-like curves.
Though the mathematics they used is very difficult for a normal person to understand, let us break it down to an example paradox and an outcome of their proof.
Example: Let us think that backward time travel is possible for a moment. You travelled in time with an intent to stop COVID-19’s patient zero from being exposed to the virus. But if you succeed in doing that, there won’t be any COVID-19 in future thus you shouldn’t have any intent to stop it.
This is a paradox. As an answer to this paradox, the proof says that 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.
Basically, it says that if you travel into past, you will be free to do anything and no matter what you do, the events will always adjust themselves and prevent a possible paradox.
The mathematical processes discovered by the duo, show that time travel with free will is logically possible in our universe without any paradox.
Germain Tobar, Fabio Costa. Reversible dynamics with closed time-like curves and freedom of choice. Classical and Quantum Gravity (2020). DOI: 10.1088/1361-6382/aba4bc