Is a time machine viable? Is it possible to make a time machine ?

To put it simply: no way.

Physicists believe that the law of cause and effect cannot be broken, and even if, according to the general theory of relativity, there can be closed time-like worldlines (that is, moving along these worldlines, the object can return to its past), physicists also believe that such space-time does not really exist.

The general theory of relativity believes that if you can obtain **sufficient** negative energy matter, through a certain method, you can create a traversable wormhole, and the traversable wormhole can be converted into a time machine, but on the one hand, the required mass of negative energy matter is extremely large, and there is no hope that so much negative energy matter can be obtained with today's technology of human beings, on the other hand, even if a time machine is made according to this method, the particles of the future will continue to cycle through and multiply at both ends of the time machine, producing positive feedbackand eventually destroy the time machine. Therefore, even if such a time machine is manufactured, it cannot exist stably.

At least in today's mainstream physics consensus, a time machine is impossible.

Students who are trying to go back in time beyond the speed of light note that it is impossible to accelerate an object beyond the speed of light, and this is forbidden by the special and general theories of relativity.

When human civilization reaches the point where it can build light-speed aircraft, a time machine will be possible.

1. Speaking of Doraemon's classic cartoon, many people will think of many things. And all kinds of magical props in cartoons have been talked about by many people so far. Among them, inadvertently we have to talk about the time machine, which is the sports car-like thing you see in the opening **.

2. Now, the real time machine is about to appear! An important document from Google's famous Y Lab**, called Project Flux, is said to be a time travel capsule construction project.

3. Judging from the "top secret" documents of the outflow, the shape of the flux is similar to the current four-wheeled car, allowing two people to sit, as long as the timeline and the coordinate axis of the car belt are set, it can transport people to any time and place. (This news comes from Xinhuanet).

Regarding the speed of light, it is possible to move forward: "According to Einstein's theory, the closer you get to the speed of light, the slower your time will move relatively closed". In layman's terms, a person travels at the speed of light, and his two hours are longer than those of a stationary person for two hours.

That is, at the same time, the person who has the speed of light will travel a long distance longer than someone who does not have the speed of light. Therefore, the time reversal is reached, and as long as the time is long enough and continues to develop, the desired point in time can be reached.