Where are the Time Travelers?
A constant theme within Science Fiction stories and one that’s always living in our fantasies, Time travel has shaped our imaginations for years. But while we all imagine the thought of time travelling, is it even possible?
Thanks to Einstein, we know that the answer is yes. There are no laws in physics that prevent time travel from being possible, at least to the future, as explained by Professor Brian Greene.
However, that does leave the possibility of going back unanswered. But let’s imagine that it is possible, after all it seems that every law of physics has some kind of loophole, even the speed limit of the universe, the speed of light, can be overcome if you warp space. So what if time travel is possible, then where are all the time travelers? One would imagine that people from other times would come to observe historic events. Stephen Hawking famously threw a party for time travelers and only gave out the invitations after the party as a way to test whether time travelers existed. However the question may be ignoring the limitations of time travel.
It may only be possible to travel from one time machine to another, using the time machines as a gate way, much like a train station. This would mean that time travelers from the future can only visit us after we ourselves create a time machine.
Alternatively, it may prove to be incredibly difficult to calculate the location one would appear if they traveled through time. Since time and space are connected, anyone who travels back in time will have to account for the location in space they will travel to as well. The Earth rotates at about 1,500 km/h, while orbiting the Sun at 1,800 km/h and our Solar System moves at over 800,000 km/h relative to the center of the Milky Way, which itself is moving through the cluster of Galaxies it’s a part of, at 18,000 km/h, and so on all the way to the expansion of space itself.
To put it simply, imagine throwing a basketball into a moving hoop, if you don’t account for the movement of the hoop you’ll miss your shot. This means that were one to travel back in time, without accounting for their trajectory through space, they would end up somewhere in the void of Space. We may be able to write an algorithm to account for the Earth’s position in space to correct for those issues but first we would have to know all the variables, for instance it may be that our whole Universe is moving with respect to other Universes in the Multiverse, and as such we must know the speed of its movement in order to calculate it accurately.
But even beyond the technical problems lie ethical ones. What would be the ethical concerns of travelling through time? If time travel to the past was ever made possible one would have to consider the ramifications of going back, on what kind of influence they could have on the timeline. There are a number of different theories on time travelling, some suggest that travelling back would alter the timeline, some suggest that it would create a new alternate timeline from the original, but in every case changing things in the past could have great influences on the future.
The Butterfly effect is the term used to explain how a simple action like the flapping of a Butterfly’s wings can cause a hurricane. Primarily used to explain the weather, it explains that every action, no matter how small, builds in influence over time until it creates a major outcome. So messing with the timeline, even slightly, could have significant consequences later on. For this reason if time travel is invented in the future it’s use would have to be regulated.
Additionally people would want to take advantage of time travel for personal gain, using it to win gambling bets and take advantage of their knowledge of future outcomes. Perhaps best highlighted by Biff from Back to the Future, who used the DeLorean to go back in time to make money.
As such any influence time travelers have on the past would be deemed ethically and morally wrong and would have rules to prevent misuse. For this reason it is unlikely that we will ever make contact with time travelers, even if they do visit us.
Time travelers may have technology that makes them invisible to the physical world, being intangible and invisible so as to prevent them from having any influence on the past. Alternatively, and probably more likely, it may be that the future has “Time Viewing” technology, allowing them to see into the past without having to travel to it, essentially putting history on a Television screen, which gives new meaning to the History channel. This means that Stephen Hawking’s time traveler’s party experiment was always doomed to fail.