Have you ever noticed in science fiction stories involving time machines, that the machines in question seem to defy all logical explanation? And I don’t just mean the physics of time travel, though that’s an interesting topic by itself. No, what I mean is how the machine seems to ignore physical location when travelling through time. You might call this the trouble with time travel, because alliteration is fun.
In any story, a degree of narrative convenience is necessary simply for the sake of having the story happen. But one convenience – or more accurately, contrivance – time travel stories too often suffer from is failing to take into account the fact that Earth is a celestial body travelling at some 67,000 MPH. It wouldn’t be in the same place when travelling through time!
Let’s say you build your time machine in your London flat’s basement. You climb in, start the machine up, and decide that as a simple test you’ll go back in time by precisely 24 hours. So where was the Earth 24 hours ago? If it travels 67,000 miles every single hour, that gives us a rough figure of 1,608,000 miles travelled.
Our scientist, who probably isn’t very bright if he’s not thought about this issue, sits in his machine. He prods the buttons, sets the Flux Capacitor just so, and hits the big red GO button. He travels back 24 hours to the exact same spot he’s in right now. Unfortunately, the spot he’s in right now is based on the position of Earth right now as well, not the Earth of 24 hours ago. (more…)