Physicist solved the "paradox of the murdered grandfather" and proved the possibility of time travel

A physicist at Vanderbilt University in the United States claims to have solved the "murdered grandfather paradox." This, in theory, could make time travel possible.

Time travel has been dismissed as impossible in part because of the infamous "grandfather paradox," which asks whether a person will be born who kills his or her ancestor while traveling through time. However, a new study may solve this problem, LiveScience writes.

By combining general relativity, quantum mechanics, and thermodynamics, the study demonstrates that time travel may be possible, experts say.

Physics of time loops

According to scientists, everyday understanding of time is based on Newtonian physics, where events progress linearly from the past to the future. However, Einstein's theory of relativity casts doubt on this intuitive assumption. It shows that the fabric of space-time can behave in a way that contradicts common sense, as evidenced by phenomena such as black holes.

One of the most interesting assumptions is the potential existence of closed time-like curves-pathways in space-time that go backward, theoretically allowing a traveler to return to the past, scientists say.

"In general relativity, all forms of energy and momentum are gravitationally driven, not just mass. This means that if matter rotates, it can 'pull' space-time along with it," said Lorenzo Gavassino, a physicist at Vanderbilt University and author of the study.

In a universe where all matter rotates, space-time can become so distorted that time actually bends backward, forming a loop. A spaceship traveling through such a loop could theoretically return to its starting point not only in space but also in time, the scientist suggests.

Paradoxes of time travel

One of the biggest problems with time travel is the paradoxes it creates, such as the "murdered grandfather", which is just one example, the researcher says.

"The law of increasing entropy, a thermodynamic quantity that measures the degree of disorder in a system, is the only law of physics that distinguishes between the past and the future. It is known that entropy is the only reason why we remember past events and cannot predict future ones," Gavassino said.

Quantum resolution of paradoxes

Drawing inspiration from the work of physicist Carlo Rovelli, Gavassino demonstrated in his research that the behavior of thermodynamics fundamentally changes on a closed time-like curve. In such a loop, quantum fluctuations arise that can erase entropy, a process that is fundamentally different from what we experience in everyday life.

According to the physicist, these fluctuations can have dramatic consequences for a time traveler. For example, when entropy decreases, a person's memories can disappear and aging can be reversed. "This phenomenon can even make irreversible events, like killing your grandfather, temporary in a time loop, completely negating the paradox," the researcher suggested.

"I applied the standard structure of quantum mechanics and demonstrated that the self-consistency of history naturally follows from quantum laws," Gavassino emphasized.

Theoretical and practical implications

Although Lorenzo Gavassino's findings offer a convincing theoretical basis for time travel, the question remains: do closed time-like curves actually exist in the real universe? Most physicists are skeptical about this question.

Nevertheless, experts say that Gavassino's work is valuable for expanding the boundaries of human understanding of the universe.

The paradox of the murdered grandfather, first described by science fiction writer René Barjavel in his 1943 book "Le Voyageur imprudent," is as follows: suppose a person used a time machine to travel back in time and killed his biological grandfather before the latter met the traveler's grandmother.

As a result, one of the traveler's parents (and, as a result, the traveler himself) would never have been born. This means that he would ultimately not be able to time travel, which in turn means that his grandfather would have remained alive and the traveler would have been born, allowing him to time travel and kill his grandfather. Thus, each possibility implies the negation of itself, creating a logical paradox, Wikipedia writes.

Only verified information is available on the OBOZ.UA Telegram channel and Viber. Do not fall for fakes!