Since we recently covered the topic of time travel, first by philosophically musing a bit about it, and then by recommending a few nice movies built around the idea, perhaps it’s about time to discuss whether it would be plausible to conceive it or not. After a bit of digging online, trying to separate the hysterically romantic from the scientific, we’ve reached the conclusion that it’s all a matter closer to a philosophical debate anyway. Still, it’s more interesting to hear what scientists say about what would make time travel possible, philosophically, so we went with that. Here’s the summary and prepare to be surprised.
For a long time, physicists (which are the most entitled to have an opinion on the matter) widely affirmed that no, it’s not plausible to assume time travel as a possibility, since time doesn’t really exist, but is more of a human mental construct. Another popular common opinion shared by philosophers, this time, was that even if time travel could somehow be made possible, it would only be conceivable as travel to the past, since the past at least happened, but the future doesn’t really exist at all. Both points seem pretty legit, which is why the issue wasn’t pursued further than this, at least on a larger scale, until recently.
So, Is Time Travel Possible?
General relativity was the first kind of physics that considered the hypothesis as something worth pondering about. According to this branch, certain types of movement through space could spark up some time travel, if performed in their specific way, since, you know, time and space are so closely sewn together and all. So, to make time travel possible according to general relativity, you would need to enter a closed timeline curve (sounds pretty fancy if we put it like that). In plain English, if you were to move away from Earth’s rotations, at relativistic velocities, and then you would return, more time would have passed in the meantime on Earth than for you, thus you traveled into the future a little bit. On the other hand, backwards time travel wouldn’t be possible at all, according again to general relativity theorists, because that would open the way to too many paradoxes. For example, a minor change in the past could endanger your very existence (or the so-called grandfather paradox).
Newer Views: Stephen Hawking and Brian Cox
However, fresher takes on the matter have been made by contemporary scientists that have gone as far as to deem time travel possible, but only into the future. It seems that the old philosopher’s tale about only being plausible to travel back in time is now infirmed by the newest physics theories. Let’s see what these two prominent figures have to say. Both Stephen Hawking and Brian Cox are a bit main-stream and known as the pop culture versions of a scientist, but let’s not be judgmental since the topic itself is quite bombastic, ok?
According to Stephen Hawking, who draws upon general relativity and the theory about the spatial movements, if we were to build ships which could travel faster than the speed of light, a day onboard such a ship would be a year in Earth’s time. But the motion could only be performed forward into the future, since going back in time would violate the basic principles of cause and effect. He believes that achieving the speed and light and beyond, thus making time travel possible, could help the human race to save itself, by going into our desolate future and starting over somehow (like repopulating a desolate Earth with humans long after we have gone extinct).
Professor Brian Cox shares his colleague’s views on the matter: he too says that it could only be possible to travel into the future, but once one would arrive there, returning wouldn’t be an option any more. According to him, the only thing that could make time travel possible would be the creation of a time machine (which could travel faster than the speed of light, again) and the creation or discovery of some worm holes to travel through. Those worm holes which you may be familiar with from sci-fi movies are defined as shortcuts in the space-time fabric, but most scientists continue to doubt their existence. However, this should deter us from fantasizing: as long as we have scientists as big as these two vouching for at least the possibility of it, the issue needs further investigation.