Reaching close to the speed of light Why does time slow down????

This is the special theory of relativity. No matter what your speed is, the speed of light does not change, and in a vacuum, the speed of light is always equal to c=3*10 8m s

When you fly at sub-light speed, the speed of light you emit is c, and the speed of light emitted by people on Earth at this time is also c.

You can think of it this way, you emit a beam of light in the spaceship, the direction of the speed of the light is perpendicular to the direction of flight of the spaceship, the distance of this light in the spaceship is l1, and the time you are in the spaceship is t1=l1 c.

At this time, the distance traveled by the light seen by the people on the earth is the superposition of the distance l and l1 of the spacecraft, that is, the hypotenuse l2, l2>l1, you make a diagram, then the time that the people on the earth have passed t2 = l2 c, so t2 > t1. In this way, the time is delayed.

In fact, as long as you grasp the principle that the speed of light does not change, it is easy to understand. As for why the speed of light does not change, no one has been able to explain this.

The reflection of light will spread out at the speed of light, and when it hits your eyes like this, you see the object, and when you are fast enough to catch up with or even exceed the speed of light, when you are parallel to the light, then you may see the image that happened a second ago, which is called going back in time.

You need to study the theory of relativity comprehensively to understand this, and the relevant mathematics is very difficult and cannot be explained in qualitative methods.

<>First of all, this is what many people say about Einstein's special theory of relativity.

There is a misconception that time slows down close to the speed of light, and people can live for long periods of time. The key to special relativity is "relative", and the speed of time passing needs to be compared to know, otherwise it doesn't matter how fast or slow time is. The formula for the time dilation effect of special relativity is as follows:

This formula does not mean that the faster a person moves, the slower the time he experiences and the longer his lifespan. The time dilation effect actually refers to the fact that for people who exercise at low speeds, the time experienced by people who exercise at high speeds will slip and slower and they will be able to live for a long time (the exact length depends on the speed). For example, when the relative velocity.

When the speed of light is reached, the observer is at a low speed.

will find that his time is twice as fast as that of a person who is moving at high speed - if a low-speed observer is two hours away, he will find that a person who is moving at high speed is only an hour.

However, it is not that the time of the people who are moving at high speed has slowed down, but only because of the difference in the speed of movement, in order to ensure that the speed of light is in two frames of reference.

, the rate of time lapse between frames of reference will differ, which is actually a spatiotemporal property. The time it takes for a person who moves at high speed to do anything is no different from that of a low-speed observer, and it still takes a few minutes to run a kilometer, and the time dilation effect will not affect it in any way. In short, the time dilation effect is relative to the frame of reference, and there is no concept of the rate of time passage in the frame of reference itself.

Time travel can be achieved by taking advantage of the different rates of time lapse between different frames of reference. For example, there are twins on Earth, and A rides in a spaceship.

Moving at high speed in space, B stays on Earth. Due to the different velocities, the rate of time passage is not the same between the two frames of reference, and A is slower relative to B. When A returns to Earth, he will experience less time than B, so A will be younger.

This is equivalent to A traveling to the future Earth, because what he sees is old B.