Time travel appears in many fictional works. Would it be understandable if we traveled in time or somehow bent time? Maybe we couldn’t see it with the naked eye, but scientists would certainly have noticed.
Physicists have been aware of time warping for nearly a hundred years. Actually, we also live in a time warp, the reason we can’t time travel is because we don’t have enough energy. Albert Einstein’s special theory of relativity was introduced in 1905. In his work a decade or so later, he revealed the theory of general relativity. According to this theory, gravity has a structure that bends space and time. So anything with mass bends time; but little but much.
Naturally bigger things bend time more. Black holes, the mass of which are millions of profits from the Sun, have enormous time-bending potential. As it approaches the black hole, the object’s mass warps time so much that everything inside happens much slower than what the outside observer sees.
The Sun and Earth can also bend time up to a certain scale. In 2007, NASA’s Gravity Probe B satellite observed how Earth bends time around it, supporting the general theory of relativity with 99% success. For example, people living on mountaintops actually age faster than people living at sea level.
According to the special theory of relativity, the time flow around us slows down as we get faster. We actually see this kind of time warping in our daily lives: in GPS systems. GPS satellites use incredibly precise clocks. The clocks on these satellites are adjusted according to the distance between them and the earth and the rotation speed of the satellites. Setting these clocks is very important for GPS to give accurate location.
These are not the first things that come to mind when it comes to bending of time. People usually think of machines in science fiction movies. Theoretically, time travel is possible, but practically impossible. The first of these theories is to use wormholes, which can be seen as gaps in spacetime. It is assumed that these structures emerged on a microscopic scale in the early stages of the universe. The problem is that these structures are pretty unstable and they collapse right away.
The second option is cosmic threads. There are energy lines in this hypothesis, and two threads accelerating each other can strangely twist time and create closed loops in space-time, making it possible to plunder time travel. Where do we get the enormous energy needed to speed up the ropes is another question.
If we’re going to find dark matter or exotic matter that could make time travel possible, it will probably be through observational cosmology. Our assumptions will fail on a large scale. At least that’s the case, according to Benjamin Shiaer of the University of Auckland.