I’ve always been fascinated with time travel. Or time in general. When I was about 11 or 12, I wrote a series of three short stories that centered around time travel (one involved dinosaurs, very vaguely reminiscent of “Thunder of Erebus”; another was called “Lüp” and was a lot like the “Cause and Effect” episode of Star Trek: TNG, even though I hadn’t ever seen that episode), which was conceptually brilliant (my lack of writing skills notwithstanding) despite my more or less complete lack of understanding about such things. I struggled for weeks with causality paradox inherent to the Terminator films. I almost went insane trying to figure out Primer. Time travel is one of those things for which fascination isn’t at all tempered by a lack of understanding.
When I saw Toomey’s The New Time Travelers on the library shelf, a lifetime of latent interest couldn’t be ignored. It promised to be a book of the sort which manages to make hard science accessible (see also Stephen Hawking’s books). Time travel is, if nothing else, a boatload of math, which is my archnemesis. Toomey is an English teacher, if that gives you any indication of the context in which it was written. Don’t let that fool you, though: David Foster Wallace, for instance, wrote a book on the concept of infinity which was obstreperously dense. I found out only later that his undergrad degree was in math.
Toomey, though, has no such surprised. Granted, the concepts of time travel are still extraordinarily difficult to wrap one’s mind around, aided only slightly by the book’s multitude of graphs and diagrams, but Toomey is clearly trying his best to not only explain the complicated mathematics behind advanced physics, but also give historical and cultural context to the idea. The book doesn’t even broach time travel for a while: Toomey begins with H.G. Well’s The Time machine and then starts by laying a working foundation for modern physics: relatively, quantum theory, &c. are all necessary to explain the vagaries of time travel.
Of course, we’re not talking about a wild-eyed Doc Brown roaring up in the DeLorean. We’re talking about the peculiar qualities of light, and the theoretical behavior of regular matter at relativistic speeds; that is, no hopping in a machine and killing a butterfly in the Jurassic, and no blasting forward and meeting the Morlocks. The best you could do would travel in a very fast spaceship for a few years and then come back to earth to find that hundreds or thousands of years had passed (depending on how close to the speed of light you got) because of the different reference frames. For the last century, physicists have played on and off with the idea, passing thought experiments around like a doobie.
Despite being mostly theory and guesswork (time travel is the sudoku of modern physics), the idea still remains fascinating. I was impressed at the thorough but approachable treatment that Toomey gave it. if you want more than Wikipedia can provide on the subject, give the book a try.