I was walking through the parking lot to my car after work when I started daydreaming about all the people who had been there before me; earlier the same day, or perhaps a month or a year ago, meandering to their cars, stopping to check messages, and standing, talking to coworkers. Science fiction writers love to explore this “space” when they write about time travel. Michael Crichton, for one, tended to incorporate more science in his sci-fi than others, introducing the idea that while time travel is not possible, travel to other dimensions might be. In H.G. Wells’ The Time Machine, the notion of being able to journey to another time in the future or the past was first popularized. In his story, the Time Traveler was able to travel to a very distant future version of earth, while staying in the same geographical location. Aside from Doctor Who, most other time-travelling narratives stick to this point. And so, as I perambulated and wondered about the past lives that, if only on the same timeline, would have crossed my path, or bumped into me if I weren’t looking.
But while it’s proper to consider that time travel, if it were possible at all, would limit the voyage moving in time, it is not reasonable to assume the traveller would also change position, geographically. Or is it? As my daydream began to mutate (as they often do), it dawned on me that if I were to travel backward one year, I might end up somewhere else. You see, 365 days ago was not 19 September, but instead 20 September 2015. But ignoring the very predictable results of Daylight Savings changes in the Gregorian calendar, we must shift our attention to the fact that where you are, right now, in space is unknown.
The earth is currently orbiting the sun at a speed of 108,000 km/h, or about 30 km/s. Therefore, if you travelled instantaneously to 1 second in the future, and you didn’t change your location, you would be 30 kilometers away from your current position. You would have teleported on top of travelling in time. Also, consider that the sun is moving around the center of the Milky Way, around 800 km/h. So, if you wanted to travel in time, but you didn’t want to move, you would have to predict where the earth would be at that time. Since the earth and the sun and the galaxy are all moving at the same time, this would require some awesome math. Now, considering that we are already in the possession of some awesome mathematical principles, created by some equally awesome mathematical geniuses, we could extrapolate and get a pretty accurate calculation of where you might end up. But it wouldn’t be perfect, and so you could still end up in the middle of a mountain or floating in space, but within tolerance (inside the orbit of most satellites.) This is assuming we have a good idea of what a fixed point in space looks like.
If you wanted to travel forward in time to 2150, you would need to know just where the earth and the sun would be at that time, that second. But assuming we could overcome this obstacle, there are other problems to consider, like exposure to pathogens that do not exist in our time, or the increase in pollution, or incomprehensible dialects. Naturally, not having nearly enough money to get around would pose a serious problem (someone from the late 1800’s would be absolutely shocked at the idea of spending $40 on a meal). No doubt, the increase in population and significant lack of privacy would be disturbing to our time traveller, not to mention being completely ignorant of 130 years of history. In the Back to the Future series of films, several characters move backward and forward through time with very little difficulty, aside from having to fuel the time machine, but it would most likely be traumatic.
Of course, time travel is not a reality, except for the slow, day-to-day type with which we are all familiar. That’s alright with me. Gradual change is much easier to accept. The changes we face now are quite dramatic enough, and most of us are barely able to keep up. History reveals that civilizations have embraced change, and then violently rejected it. Swings in public opinion seem to come back to their starting point after a generation or two, or a millennium. But before we presume we have come so far in our modern civilization, we should look at our current form of entertainment and make sure it is not worse than gladiators fighting to the death. It may look truly bizarre to future historians, our taste for pugilism might be horrifying, or charming, whichever the case may be.
I guess we’re fortunate that there are things that are beyond our ability to comprehend. Otherwise, we would have very little in the way of fantasy. Science fiction would be nonexistent, and our daydreams would be pretty dull.