A new study out of the University Of Queensland attempts to explain how paradox-free time travel may be possible.
Undergraduate student Germain Tobar, alongside physicist Dr. Fabio Costa, did the math. Their goal was to find a possible solution to the so-called “grandfather paradox” — if someone traveled back in time and murdered his or her grandfather, that would prevent the time travel from having ever taken place, thus the paradox.
However, according to their study, they may have found a hypothetical scenario in which you could time travel, and even meet yourself, without causing any kind of paradox or disturbance to the timeline.
“Some physicists say [time travel] is possible, but logically it’s hard to accept because that would affect our freedom to make any arbitrary action. It would mean you can time travel, but you cannot do anything that would cause a paradox to occur. However the researchers say their work shows that neither of these conditions have to be the case, and it is possible for events to adjust themselves to be logically consistent with any action that the time traveller makes.”
Their idea suggests that, if one variable in the timeline is changed, another variable will simply swoop in to take its place, continuing (or “recalibrating” as Tobar says) the timeline along the exact same path. The universe, in this way, is “self-correcting.”
From a science fiction standpoint, this sort of idea isn’t particularly new. But seeing the math laid out and a possible explanation for why this might (hypothetically) be the case in the real world is pretty interesting.
Just off the top of my head, the 2002 adaptation of The Time Machine shows this kind of “universal recalibration” at work. The time traveler tries desperately to save his fiance from dying. In the original timeline, she dies after a mugging. In an altered timeline, when the traveler attempts to save her, she’s run over by a carriage. “I could come back a thousand times, see her die a thousand ways,” the traveler says. The variables change to compensate for the existence of the time traveler.
At least, that’s a fantastical rendition of a similar idea.
“…when multiple local regions communicate with each other in the presence of [closed time-like curves], there is a broad range of communication scenarios which still allow freedom of choice for observers in each region without the development of a logical inconsistency such as a grandfather paradox.”
You can read the full paper, titled “Reversible dynamics with closed time-like curves and freedom of choice,” right over here. It’s much more technical than the press release lets on, which elevates it above the usual time travel speculation.
Now, dipping into ye olde John Titor file (I can’t help it), what did he have to say about paradoxes?
“…the reason there are no paradoxes is because the universe doesn’t care how we react to its handy-work. In a Universe made up of infinite worldliness (super universe), everything is possible and has a 100% probability, therefore…no paradoxes.”
The universe doesn’t care. There’s a certain elegance to that.