Saturday, May 2, 2015

Paradoxes of Time Travel

While time travel can sound fun and even plausible, we might run into some serious problems. These problems stem not from equations not being satisfied, but logic being broken. In this blog post, I am going to discuss three different types of paradoxes associating with traveling back in time as well as solutions to try and resolve these issues.

The first of these paradoxes is the bootstrap paradox, a paradox that is related to original information. This paradox does not necessarily change the course of history, but it does blur out the origin of the object in question. Let’s say I was to go into the future to learn about a single equation that can explain every phenomenon in the Universe and then told someone about it after I returned from my trip. That person may end up writing a book that contains information about that equation, which is why the future knows about that equation. In the end, we end questioning who and when this equation was made. 

Continuing on with paradoxes, the predestination paradox discusses the implications of changing an event in the past because of something that happened in the present. A classic example is of a man going back in time to save his girlfriend from a car accident. As he is in the past driving quickly to the eventual accident location, he hits his girlfriend, and kills her. He caused the death that made him travel back to the past in the first place.

The last paradox we are going to observe is the grandfather paradox, one of most well known paradoxes of time travel. It’s a pretty simple scenario; you go back in time to kill your grandfather. The problem to this is that if your grandfather is dead, then he wouldn’t be able to give birth to your parents. Without your parents existing, then you can’t exist. Yet you were able to travel back in time to kill your grandfather.

But we also have theories to put down these paradoxes. The Novikov self-consistency principle says that anything a time traveler does in the past, is already represented in the present time. This principle believes the Universe “prohibits” inconsistency, that free-will of a time traveler is limited when he/she travels. Another possibility is that maybe one does can do anything they want in the past. But changing anything in the past will lead to a different parallel Universe. By changing what you do in the past, you essentially split the universe into two scenarios. The future you are from will stay the same because that was already determined from the past. But your new change in the past, will create another world where the future will be different because of that change. So if you were to go back and somehow save the dinosaur species from extinction, there would still be no dinosaurs in the present day. This is because the instant you save the dinosaurs, you have essentially split the Universe to go on two alternative paths; one path with a world of dinos; another with just humans.

All in all, these paradoxes clash with the idea of traveling back in time. If we want to resolve these issues, we need to think outside the box, such as with Novikov self-consistency principle. Or we need to start finding evidence for parallel universes. These paradoxes pose more questions that physicists and astronomers need to answer. It creates more opportunities to learn and discover about new things.


"3 Time Travel Paradoxes!!" YouTube. YouTube. Web. 25 Apr. 2015.
"Time Travel Simulation Resolves." Scientific American Global RSS. Web. 25 Apr. 2015.
- Eric Lee