A physicist who identifies himself these days as a “cyber-control scientist,” my dad (whose bio you can read here) loves to dig into the feasibility of pop culture narratives.
It’s true that time is reversible, but entropy is not. They created a disorder and they have to bring back the order in an alternative universe. I can conceive of that. But you can’t violate the second law of thermodynamics.
This is, perhaps, the best film blog post of 2011. Definitely worth a read whether you like the film or not.