No one has yet been able to travel through time – at least to our knowledge – but the question of whether or not such a feat would be theoretically possible continues to fascinate scientists.
Like movies like terminator, Donnie Darko, Back to the Future and many others show, the passage of time creates a lot of problems for the fundamental rules of the Universe: if you go back in time and stop your parents from meeting, for example, how can you exist to go back in time in the first place?
It’s a monumental scratch known as “Grandpa’s Paradox,” but in September last year, physics student Germain Tobar of the University of Queensland in Australia said he learned how to “square the numbers” to make a living in viable time. without paradoxes.
“Classical dynamics says that if you know the state of a system at some point, this can tell us the whole history of the system,” Tobar said in September 2020.
“However, Einstein’s theory of general relativity predicts the existence of time loops or time travel – where an event can be both in the past and in its future – theoretically turning the study of dynamics on its head.”
Calculations show that space-time can adapt to avoid paradoxes.
To use a current example, imagine a time traveler traveling in the past to stop the spread of a disease – if the mission were successful, the time traveler would have no disease to go back in time to defeat it.
Tobar’s work suggests that the disease would still escape in another way, in another way, or in another way, eliminating the paradox. Whatever time traveler did, the disease would not be stopped.
Tobar’s work is not easy to dig for non-mathematicians, but looks at the influence of deterministic processes (without any randomness) on an arbitrary number of regions in the space-time continuum and demonstrates how both closed curves resemble time (as predicted by Einstein). they can conform to the rules of free will and classical physics.
“Mathematics checks – and the results are science fiction,” said physicist Fabio Costa of the University of Queensland, who oversaw the research.
Fabio Costa (left) and Germain Tobar (right). (Ho Vu)
The new research solves the problem with another hypothesis, that time travel is possible, but that time travel would be restricted in what they did, to stop them from creating a paradox. In this model, time travelers are free to do whatever they want, but paradoxes are not possible.
While the numbers might be solved, the bending of space and time to get into the past remains elusive – the time machines that scientists have designed so far are so high that they now exist only as calculations on a page.
We might get there one day – Stephen Hawking certainly thought it was possible – and if we do, this new research suggests that we would be free to do whatever we wanted the world to do in the past: readjust Consequently.
“Try as much as you can to create a paradox, events will always be adjusted to avoid any inconsistencies,” says Costa. “The range of mathematical processes we have discovered shows that time travel with free will is logically possible in our universe, without any paradox.”
The research was published in Classical and quantum gravity.
A version of this article was first published in September 2020.