Wednesday, November 23, 2016

The Problem with Time Travel

From author Steve McEllistrem:
One theory for time travel involves wormholes, which might allow for a shortcut from one point in space to another and from one point in time to another, yet many scientists who study this subject believe it isn’t possible. Another theory is that cosmic strings might contain enough mass that they could warp space-time around them, allowing for movement from one point in time to another. Again, we have no evidence that it’s possible, only a theory. The only way we know of for traveling through time is to move at close to the speed of light. Time slows down when we do that, so if we could get inside a spaceship and travel at nearly the speed of light, much more time would elapse outside the ship than in it and we could see the future. The problem is, we couldn’t get back to the past (our former present).

However, most time travel stories, even those that involve traveling to the future, generally include either a return to the present or (traveling backwards in time) or describe traveling to the past to change some event that will then change the future (the present in the story). If such stories are well done, well written, they can be enjoyable, but it’s difficult to avoid the trap of temporal contradiction (or temporal paradox) and it’s essentially impossible to explain how time travel would work in a way that satisfies me. The best example of the paradox is probably going back in time and somehow killing your grandparents or parents so that you are not born. How then can you exist to travel back in time and kill them? As a result, time travel stories fit much more securely in the fantasy genre than in science fiction. And it takes an awfully good fantasy to appeal to me. Dune was one such story, The Lord of the Rings another. (Read more.)

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