"Reliable time travel might take a while".
April 28, 2023
"Reliable time travel might take a while".
Says the new, but the journey to a reliable future must start today.
Now that the topics that talk about spacetime, the present and the uncertain future are back in fashion...
Time, you slippery bastard -- the immutable aspect of reality cannot be controlled any more closely than one can stifle the flow of sand through a tightly gripped fist. Time can only be observed, and even then, only indirectly based on the entropy generated by its passage. But that hasn’t stopped humanity from wishing for and working towards a feasible means of going back in time since our earliest ancestor smacked their palm against their forehead and muttered to themselves, “Aw cripes you idiot, why did you say that, what were you even thinking?”
“There is definitely something funny going on with time travel,” Dr. Paul M. Sutter, research professor in astrophysics at the Institute for Advanced Computational Science at Stony Brook University, told Engadget. “We have one theory of physics which is general relativity -- our story of gravity -- which is perfectly cool with time travel. You can construct special situations that allow you to travel back in time but, every other area of physics says, no, you can't travel back in time. So, which one is right?”
On Monday, a research team from the University of Queensland, Australia reported that they had potentially, mathematically devised a solution to one of the primary roadblocks against time travel. The Grandfather paradox, as depicted in Back to the Future, is a veritable brick wall of theoretical physics nuh-uhs. Essentially, the grandfather paradox argues that if you went back in time to kill your own grandfather, then you wouldn’t ever have been born to go back in time to kill your grandfather because he would already be dead and you wouldn’t exist on account of the lack of necessary reproduction.
However, the Queensland University study suggests that the universe is slightly more flexible than that. Their work argues that even if one were to go back in time and off their grandpappy, the universe would reorganize itself around the event in such a way that the existing timeline remains valid, regardless of whatever action the time traveller took.
“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,” University of Queensla physicist Dr Fabio Costa said in a statement. “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 to 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.”
That is, imagine if Marty McFly had let Biff beat the heck out of his dad. The universe automatically would have found a way to ensure that Marty still existed, somehow, to go back and change history this way. He and his siblings wouldn’t have disappeared from the photograph, because, well, we don’t want to imagine how.
