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.
Journal Reference:
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
This is essentially the theory of narrative causality espoused by Terry Pratchett’s Discworld series. The history monks are in charge of ensuring that the sequence of events follow the timeline in their proper order. What this seems to say is that, while events aren’t necessarily predestined, once they occur, their presence in the timeline is unalterable even though the means by which they occur is. So even if Gavrilo Princip hadn’t shot the archduke, someone else would have. But there would be no way to get the archduke to fall down the stairs that morning and avoid him getting in the car at all. Or if there were, there would be no way to prevent the same sequence of events from occurring at some other equally critical point in time leading to the same chain of results. The dominoes are set up and it doesn’t matter which one you trigger to set the other ones off. This is essentially predestination.
Where this is problematic is when you consider the idea of multiverses. This discovery means that time travel is stuck on the rails of whatever universe you are in at the time and that Universe is rigidly predestined. To avoid the events you would actually have to travel sideways to a different narrative (universe) entirely rather than back and forth on the same rail. But you can’t create your own shunting station by altering events in this universe. You have to exit the universe entirely and go to another one which fits your desired outcome. Less Back to the Future, more Michael Crichton’s Timeline.
This article says very little. How about explaining in layman’s term what this breakthrough actually involves?
But this theory of, you can not change the past; this actually existed before. I knew an example of this sort.
Like if I travel back in time and replace Hitler with another baby, that replaced kid will grow up to be Hitler. So you can’t change the past. So I don’t understand what this new discovery is. But also I am no genius to understand the math.