1. The speed of light remains unchanged.
Suppose a train runs north at a speed of 300 kilometers per hour and a car runs north at a speed of 150 kilometers per hour, people in the car will find that the speed of the train is 150 kilometers per hour. The conclusion is that the speed of an object's motion depends not only on its own speed, but also on the speed of the observer's movement.
This conclusion only applies to objects moving at low speeds (such as trains, such as the motion of the earth). Once the speed accelerates to the speed of light (300,000 kilometers per second) or is close to the speed of light, this daily experience fails, because a large number of accurate experiments have proved that the speed of light is unchanged. That is to say, the speed of light is a fixed value and a constant, which does not change with the observer's motion.
Another example: Suppose a beam of light moves north at 300,000 kilometers per second and a spaceship moves north at 150,000 kilometers per second. How fast will the light be found in the spaceship? According to our daily experience, the speed of this beam of light should be 150,000 kilometers per second. Wrong! People in the spaceship will find that the speed of this beam of light is still 300,000 kilometers per second.
2.Equivalence principle.
Suppose we are sitting in a boat, when the boat is running at a uniform speed, we won't feel the boat moving. Similarly, the earth orbits the sun at 30 kilometers per second and rotates at 500 meters per second. We can't feel the earth moving.
Now suppose that we are in an elevator, when the elevator accelerates evenly up, we won't feel the elevator moving. We will only feel a force pulling us down, just as the mass of the earth fixes us to the surface so that we do not leave the earth.
Einstein infers that speed and mass are equivalent, and they play the same role in slowing time. Of course, there is a classic logical reasoning process in this regard, and I won't elaborate on it.)
Conclusion: Not only the speed can change space-time, but also the quality can change space-time.
Comments