Which of Einstein's theories provide a theoretical basis for traveling through time and space?

Theory 1: Special Relativity -Moment Inflation Effect

The theory was put forward by Albert Einstein, on the one hand, the theory abandoned Newton's classical view of space and time, and relative to the principle of relativity, which proposed that The speed of time passing is not a layer of invariance, but with the size of the object's speed of movement in the corresponding change. That is to say, the faster the speed of movement of the object, the slower it is relative to the passing of time, if the speed of movement of the object can reach the speed of light, the relative passing of time is 0, that is, the moment will stop.

Theory 2: The use of black holes

In Einstein's theory of general relativity, there is a paragraph: space-time is one, gravity comes from the distortion of space, the formation of the distortion of space is the cause of the large mass of matter.

The combination of these three conclusions can be understood as follows: massive objects in the continuous change will form a cosmic space distortion, which develops into a strong gravitational force, and because space-time is one, space is distorted together with the moment is also distorted, so the moment around the massive object is not the same as the speed of the other localities.

Such an effect is very obvious around the black hole, join the conditions, if possible, mankind has developed the ability to take a spaceship circling the black hole for a few weeks (outside the field of view), when you take the spaceship back to find that the Earth has been many years, in other words, that is, you flew into the future.

Without Einstein's theory of relativity, the topics we talk about today, including time travel, would all be empty words, and the exploration of space and time would be a constant source of debate for mankind. According to Einstein, high-speed, long-distance movement of the object can be completed space-time interpretation, but only into the future.

To put it another way, when an object flies from Earth to a place 500 light-years away from Earth at nearly the speed of light, it's the equivalent of it being only a few years older than it was before, but the actual Earth has already passed by centuries, if not millennia. It wouldn't be the equivalent of going straight from 2019 to 4634, which would presumably be long gone.

The theoretical way to travel through the future is to move at high speeds and long distances, but it's simply not possible for humans to do that right now, and it also has a lot of uncontrollable factors that limit the human race's ability to get out of the confines of time in every way.