Some physicists actually liken time to a river, says Kaku, which meanders at different speeds through the universe. “There are two ways to resolve the time-travel paradox,” Kaku explains. “One way is, the river of time [forks] into two rivers, so you change a parallel universe’s path, not your own path.” This theory, which asserts that our universe may be just one of an infinite number of universes, is known as the Multiverse Theory, and it’s what Kaku personally believes. The creators of Lost, however, have taken a different approach, one pushed by some Russian physicists, according to Kaku. “They have whirlpools in the river of time, so you leave the timeline and go back into the past,” Kaku says. “They believe that when you go back on a different path, there’s some kind of physical principle preventing you from changing the past to make the future impossible.”
Gracias a Edu.