One of the most amazing concepts, even if it’s not the most original, in Harry Potter is time traveling with the use of a time turner. In Roger Highfield’s book, The Science of Harry Potter, he delves into the likelihood of this phenomenon with theories on how it can happen in real life.
Use of Wormholes?
One explanation on how Hermione’s time turner works is the possibility of using wormholes. In theory, a wormhole functions by allowing a link between two different places in space or periods in time. While this concept does not disapprove space-time travel, Stephen Hawking (a well-renowned physicist) states that though wormholes may be created, it is likely to destabilize as soon as any particle is inserted into it thus making it the least favorable way of space-time travel.
Travel to the future but not to the past?
It is said that time travel apparatuses can only be used by going to the future. It is not possible to go back in time before the apparatus was created. This does make sense and limits the possibility of paradoxes.
We all know the warning that McGonagall told Hermione about the dangers of altering history. Highfield says that it references to the grandfather paradox in which you go back in time, kill your grandfather and ultimately making sure your mother is never born causing you to be nonexistent and unable to go back in time to actually kill your grandfather. Complicated? Well, thankfully, David Deutsch from Oxford University actually states that there is no grandfather paradox. Instead, there are different branches of reality.
This theory, as first proposed by Erwin Schrödinger, was further developed by Hugh Everett III. He declared that the universe is rooted in an infinitely larger space called the multiverse where parallel universes are relentlessly multiplying causing a numerous amount of possibilities. For example, in another reality, I’ll probably be out doing something more fruitful than writing this blog post (like marrying Ezra Miller). You, in turn, will be equally be doing something more productive than reading what I’m writing.
If we accept this theory, then we might say that Hermione doesn’t actually travel back and forth through time. Instead, she creates a different reality and as Deutsch says, “Make things happen there”. This then allows a “time traveler” to alter the past without producing the grandfather paradox.
With this in mind, we don’t actually time travel. We instead “hop universes” like Doctor Who but not really.