Good news if you don’t know where to travel next summer: a mathematician has proven that time travel would be physically feasible, without messing up the present and risking triggering a chain reaction that you wouldn’t be able to control. Admit that you are reassured.
Germain Tobar and Fabio Costa were both working at the University of Queensland when their results were published in the journal Classical and Quantum Gravity. They declare that they have found a mathematical compromise resolving a major logical paradox in a model of time travel, a paradox that we will try to summarize for you taking into account the fact that you have two New Year’s Eves in your legs, and that it surely plays a role. on your comprehension skills. While the math employed here is complex, it can be reduced to relatively simple logic, says an article in Popular Mechanics, and that’s a good thing.
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When we talk about time travel, we often talk about closed time-like curves (CTC), a concept introduced by Albert Einstein. Tobar and Costa support the following theory: «TAs long as two elements of a scenario in a CTC remain in “causal order” when you leave, the rest is subject to free local will.e.»
Hitler or the patient 0
Let’s take a concrete example, that of Covid-19. «Imagine traveling back in time to try to stop Patient Zero from covid-19 of being exposed to the virusexplains Costa. However, if you prevent that individual from becoming infected, it eliminates the motivation that caused you to go back to the past to stop the pandemic. It’s a paradox, an inconsistency that often leads people to think that time travel is impossible in our universe. Logically, this seems difficult to accept, because it would limit our freedom to take arbitrary actions. This means you can travel through time, but you can’t do anything that would cause a paradocar.”
He is referring here to the chain reaction that we mentioned earlier, or the famous “butterfly effect”. Your small action would unintentionally lead to big consequences. Except that a priori it won’t happen like that, and reality would always have a way of falling back on its feet, to achieve the same result. Tobar specifies:
«In the coronavirus patient zero example, you could try to prevent patient zero from becoming infected, but in doing so you could catch the virus and become patient zero yourself, or someone else would become. Whatever you did, the momentous events would recalibrate around you. No matter how hard you try to create a paradox, events will always adjust to avoid any inconsistency.tance.»
So bad news if you wanted to get rid of Hitler or prevent the Covid pandemic. For mathematicians, on the other hand, this is significant progress allowing us to refine our representations of temporality and time travel while reassuring us: the first person to develop such a technology will be able to launch adventure without fear of changing the course of history and disrupting life as we know it.
