A student and his professor from the University of Queensland in Brisbane, Australia, published a study demonstrating how time traveling without causing paradoxes is mathematically possible.
Germain Tobar, a senior advanced science major at the University of Queensland, and his professor Dr. Fabio Costa, who has a Ph.D. in theoretical physics, released this study Sept. 21 and quickly received attention from the media about it.
Costa and Tobar use an example of how this theory of time travel works by using the coronavirus in an interview released by the University of Queensland. They propose this scenario: a time traveler goes back in time to try to stop the coronavirus from ever going beyond one person.
“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,” Tobar said. “No matter what you did, the salient events would just recalibrate around you.”
Tobar went on to explain that, with this theory, a time traveler would not be able to stop the virus from spreading, because doing so would eliminate the time traveler’s motive for traveling back in time in the first place. This is called a “Grandfather Paradox” from the hypothetical situation of a time traveler going back in time and killing their own grandfather before their parent is even born, therefore preventing their own birth, which means they would never have existed to go back in time and kill their grandfather in the first place.
Jim Buchholz, professor of mathematics and physics said he feels like there are still consequences to time traveling.
“What they try to get rid of, essentially, is the Grandfather (Paradox),” Buchholz said. “The only way to get rid of this paradox is you can’t kill your (grand)father — the universe won’t allow you to — if there is only one timeline. The other option is there are multiple timelines, just like you see in the movie ‘Back to the Future.’ So what you’ve created is a universe where if you go back to your timeline, your grandfather would still be alive, but if you stay in that timeline where you killed your grandfather, your grandfather would no longer be alive and that’s OK, but in that universe you would never run into yourself.”
Buchholz said he is skeptical when physicists overuse infinity.
“Now you are saying, ‘There is an infinite number of solutions here,’ and I have a problem with infinity,” Buchholz said. “Physicists loosely use infinity, and mathematicians often warn them to be careful with infinity: It is not a real number. It is more of an idea.”
Brent Sims, junior psychology major, said he thinks time travel could still be dangerous.
“I think time is such a complex topic, let alone to try and conquer or outwit time,” Sims said. “I think even if it did change the timeline there’s too much that we don’t know when it comes to time. It’s still a gamble or a risk to put everyone through. One decision affects millions of others. (The time traveler’s) decisions are tainted now by a new outcome.”
Michael Sill, associate professor of mathematics, said that when it comes to Tobar and Fabio’s paper, people have gotten confused about how the Grandfather Paradox would work in it.
“In this paper, (Tobar) says more or less, the time travel that would be admissible would be time travel in which you could not signal to yourself,” Sill said. “That was an important sentence in his paper, that when he was describing his process function, he’s essentially saying that in order for this operation to be well-defined, you would not be able to give yourself any information (you did not already have). That would include a bullet to your grandfather, because that information would get back to you, so that is already, before things get started, thrown out as a possibility.”
Sill said this study made him wonder if it could have any implication to how God interacts with people.
“If one was to say that God is able to interact and know how things play out in our lives’ history, interact with us, that means in some ways God is able to insert himself in different points of the universe,” Sill said. “How does he accomplish that? Is it because in reality there are certain points of space-time itself that are all folded up and connected and simply he is able to traverse those types of channels? But that seems to speculative on how God interacts with the thing that he created.”
This study has not made us any closer to developing the technology to time travel, but it is a step forward in understanding time traveling without Paradoxes.