I'm going to devote my next few blog posts to the ever-popular subject of time travel. In fact, my future self will be writing these posts and emailing them back in time to me, so I won't have to do the actual work of writing them myself.
Before getting started, I wanted to mention a curious fact that most people don't know about (or at least I didn't).
I occasionally teach a seminar on science and science fiction with my colleague Jay Clayton, and the first book we assign for the course is H.G. Wells's The Time Machine. Jay claims that The Time Machine is the first true science fiction novel -- not Frankenstein or the works of Jules Verne. At the beginning of the novel, the time traveler gives a long discussion of how his time machine works -- he explains how time is really the 4th dimension, so one can move through time just as easily as travelling in the other three dimensions. I was all set to explain to my class how Einstein was the first physicist to treat time as the 4th dimension, and how this had obviously influenced Wells -- an early case of a science fiction writer incorporating new scientific discoveries into his fiction. But then I took a look at the dates -- The Time Machine came out in 1895, and Einstein published his theory of special relativity in 1905! What's going on? Maybe Wells really did have a time machine! I dug a little deeper and discovered that the idea of time as the 4th dimension didn't originate with Einstein at all -- it was a subject of discussion long before he came on the scene. (We physicists can sometimes be a little murky about the history of our own subject). On the other hand, there's no evidence that Wells actually influenced Einstein, but who knows?