Walking into the future is a dream. While the subject was until recently reserved only for science writers-fiction, some researchers are working on the subject today. It would seem that a one-way trip is possible without the possibility of a return. Unless you have a wormhole…
Back to the future, by Robert Zemeckis, rocked our childhood. At least mine. But is time travel only fictional? This is now a scientific reality, in theory. Let’s start with time, this notion experienced by all and yet so abstract. Time is very difficult to grasp. Nevertheless, we know that this one is not fixed. According to Einstein’s special theory of relativity, the speed of an object depends on its observation frame. General relativity assumes on the other hand that the flow of time also depends on the intensity of gravitation: it slows down in the vicinity of masses. However small the differences, time will always pass faster on the top floor of a building than on the ground floor.
So space and time are not absolute. They deform. The goal is to maintain the speed of light. In other words, with speed, lengths contract and durations expand. To travel in time, it would then be enough to use time dilation. The principle, as it is explained in particular in the film Interstellar, is that if you move away from the Earth at very high speed and decide to come back, then you will have aged less than the others. In other words, you will have traveled into the future.
In theory, travel to the future is therefore possible. But the biggest problem remains the speeds to be reached. The human body has its limits, however resistant it may be. We will therefore start on 9.81 m/2 which is equivalent to the terrestrial gravity felt every day. With such an acceleration, we could reach the center of the galaxy (30,000 light-years) in about forty years. You turn around and so you come back 80 years after you left. On Earth, 60,000 years will have passed! So you go away 80 years, for yourself, and jump 60,000 years into the future.
But you still have to be able to even « think up » a propulsion system that can allow this kind of trip, and even if you succeed, it is very likely that you can make the outward journey, but not the return. Unless you encounter a wormhole: two black holes connected to each other would indeed, at least in theory, allow you to travel into the future.
Go through an entrance and come out the other side. This is a shortcut to cover distances in record time. It’s a bit like taking the tunnel under the mountain by car rather than picking up your ropes and scrambling up the side of the mountain to come back down the other side. Even better: with wormholes, the farther apart you are between the two mouths, the two ends, the longer distances you can cover in a short time. If the entrance to the wormhole is close enough to Earth and you dock the exit to your ship, then you could take the entrance to the wormhole, come out on the other side and see the world as it will be. in 60,000 years, then go back in the opposite direction.
Well, this is all theoretical. Note that no wormholes have yet been observed in the wild. Their existence is so far only « probable », but in theory, we could travel in the future with such objects.
Source: Science Files