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Researchers are claiming that time travel is theoretically possible but cannot change past events.
According to theoretical physics, if a person traveled to a time in the past and tried to change things, subsequent events would correct any efforts to change the past.
To explain their findings, the researchers used the “billiard-ball model,” which visualizes the idea of “cause and effect” as a series of colliding billiard balls, and a round billiard table as a closed time-like curve. In this model, one can imagine a set of billiard balls placed on the table. If one ball is pushed from a particular position, it moves around the table, colliding with other balls in a certain pattern.
Theoretical Physicist Yasunori Nomura explained that even if the ball’s course is disrupted, its collision with other balls will enable it to return to its original path as if the disruption did not happen at all.
Citing a recent event as an example, scientist Fabio Costa said that if anyone traveled in time and tried to stop Covid-19’s first patient from getting the virus, that person would fail. He explained that preventing someone from getting the virus would create a paradox because interfering with that past event might also eliminate the reason to go back in time and stop the spread of the virus. While the person who went back in time might successfully prevent the actual first patient from being infected, he might get the virus himself and become the first patient, or cause someone else to become that patient.