There are several hypotheses about this.
According to theoretical physicist Peter Watson of Carleton University, the possibility of time travel is not yet clear. There are several options for how this would all work.
The simplest answer to the question of whether time travel is possible, according to physicist Peter Watson, is that it is not possible. If it were possible, then humanity would already be able to move in this way. In addition, time travel is against the laws of physics (the second law of thermodynamics, the theory of relativity).
Even if we assume that time travel is quite possible, today it requires too much energy.
There are also time paradoxes. Perhaps it is impossible to travel in time precisely because time must flow linearly and people cannot control it. There is also an opinion that time is just an illusion.
In reality, humanity is capable of creating a time machine. However, most of these developments will require negative energy or negative mass. Such elements simply do not exist in our universe. The thing is that if you drop a ball that has a negative mass, it will have to fall up.
Also physicist and mathematician Frank Tipler created the concept of a time machine that does not require negative mass to operate. However, the machine needs more energy than exists in our universe.
Therefore, the specialist concludes, time travel is most likely impossible. However, people still do not know this for sure.