We are all time travelers; we travel through time every millisecond of our lives. It’s just that we can only move in one direction—into the future.
Theoretically, time travel into the future and into the past are two distinct concepts. Traveling into the future could happen merely by slowing down your own time, rather than popping in and out of the future like in the television show, Primeval.
Unfortunately, at the moment, the kind of time travel we want to experience—into the past—isn’t possible. Traveling in the future is only possible if we travel more quickly or more slowly than everyone else, but then we still can’t ‘get back’ to our own time: “If you want to advance through the years a little faster than the next person, you’ll need to exploit space-time. Global positioning satellites pull this off every day, accruing an extra third-of-a-billionth of a second daily. Time passes faster in orbit, because satellites are farther away from the mass of the Earth. Down here on the surface, the planet’s mass drags on time and slows it down in small measures … According to Einstein’s theory of general relativity, gravity is a curve in space-time and astronomers regularly observe this phenomenon when they study light moving near a sufficiently massive object.
What does this have to do with time? Remember: Any event that occurs in the universe has to involve both space and time. Gravity doesn’t just pull on space; it also pulls on time.
You wouldn’t be able to notice minute changes in the flow of time, but a sufficiently massive object would make a huge difference — say, like the supermassive black hole Sagittarius A at the center of our galaxy. Here, the mass of 4 million suns exists as a single, infinitely dense point, known as a singularity. Circle this black hole for a while (without falling in) and you’d experience time at half the Earth rate. In other words, you’d round out a five-year journey to discover an entire decade had passed on Earth.” http://science.howstuffworks.com/science-vs-myth/everyday-myths/time-travel1.htm
Travel to the already lived past is another thing entirely. As David, the hero of my time travel/alternate universe After Cilmeri series, comments in Footsteps in Time, “If it were possible, why aren’t people from the future stopping by to see us?’” The esteemed Stephen Hawking says pretty much this in a long discussion on time travel to the past (holding open the idea of time travel to the future, as described above): ”Any kind of time travel to the past through wormholes or any other method is probably impossible, otherwise paradoxes would occur. So sadly, it looks like time travel to the past is never going to happen. A disappointment for dinosaur hunters and a relief for historians.” http://www.dailymail.co.uk/home/moslive/article-1269288/STEPHEN-HAWKING-How-build-time-machine.html#ixzz1pOekDSod
However, the idea of a multiverse, or a multiple parallel universes is one that holds more credence than you might think, and it is the one I have put forth in my After Cilmeri series. The existence of such a parallel universe assumes merely that space is infinite and uniformly filled with matter. This idea of parallel universes thus conveniently sidesteps one of the key complaints with time travel: the “grandfather paradox” where a time traveler goes back to kill his grandfather so that he is never born in the first place. http://www.dailygalaxy.com/my_weblog/2009/05/parallel-univer.html
So it could happen, right? Maybe not time travel to the past, per se, but traveling to an alternate universe? Regardless of whether or not we’ll accomplish it in our lifetimes, I like to think that it could, and I have based my After Cilmeri series on that idea.
Sarah Woodbury, October 7, 2013
Castaways in Time, the seventh novel in the After Cilmeri series, is available now wherever books are sold.