The concept of parallel worlds has been around for a long. We know what many dimensions and parallel worlds look like thanks to scientist Michio Kaku’s string theory and science fiction. Taking another hypothetical idea to establish the hypothetical difficulty of time travel, on the other hand, is not fair from a scientific standpoint.
As a result, we consider the general theory of relativity as a solution. Time, according to Einstein, is related to the observer’s frame of reference. To put it simply, time is a point of reference rather than a thing that exists. So, whereas certain objects, such as mass, are constant and independent of their environment, the same cannot be said for time.
And here’s how it explains the potential of time travel. According to relativity theory, the speed of light is constant, but time is only a reference. Furthermore, the speed of light is the quickest any object in the cosmos can move (based on our present knowledge). So, a person moving at the speed of light will experience time slower than others and will be traveling in the past relative to others.
Astronaut Scott Kelly, who was born six minutes after his twin brother Mark, is a wonderful illustration of this. Scott has now spent 520 days in space on the International Space Station, which is orbiting the Earth at a speed of 28,160 kilometers per hour. As a result, the time gap between the two brothers widened. “So, where[as] I used to be simply 6 minutes older, now I am 6 minutes and 5 milliseconds older,” Mark stated during a panel discussion, according to Space.com.