The original question is why can I run on a light-speed spacecraft super-light-speed ? Since the spacecraft is weighed on the scale, its mass cannot be zero, and an object with a stationary mass of non-zero cannot reach the speed of light, so the spacecraft cannot fly at the speed of light. Let's set it to be 0.01m/s different from the speed of light. Let's talk about it below.
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Let me talk about the point: Running on a spacecraft, even if you run very fast, you cannot surpass the speed of light, because speed is relative. If you are not fast in the eyes of others, no matter how fast you run, no matter how fast the spacecraft is, it is not fast.
To give the simplest example, runs on the earth. Can you say the speed exceeds the speed of Earth's revolution ? You are running on the high-speed rail. Can you say my speed is (350+10) m/s?
The reference system must be tested first. In the eyes of aliens in space, your relative speed may exceed the speed of the earth's revolution, and in the eyes of people on the platform, your speed may reach 360m/s, but this is not accurate.
How the absolute view of time subtly influences you
The principle of relativity that everyone is currently familiar with is the masterpiece of Galileo in the 17th century. If we follow this earlier version, then this problem is very simple to calculate. A person runs on the spacecraft at a speed of 10m/s. In the eyes of people outside the spacecraft, he does exceed the speed of light, exceeding 10-0.01=9.99m/s.
We want to know that people need to do two things relative to our speed, measure the time when the human spatial displacement and the displacement is applied, and then divide it to obtain the speed. You will find that when we use Galileo's theory of relativity to perform speed superposition calculations, we subtly set a prerequisite: time is absolute, and the time of the spacecraft and the observer are synchronized. If the time between them is not synchronized, it means that Galileo's theory of relativity is wrong.
The principle of the constant speed of light
What is time synchronization? It means that we were on the playground. At 12 o'clock, I saw someone throwing a goal, and you also saw it. This incident happened at the same time for us.
Originally, the earthlings, like Newton and Galileo, believed that time was like an arrow that never looked back. The speed of the arrow passing through each of us was the same. Until the emergence of electromagnetics in the 19th century, scientists found that the original understanding could not explain electromagnetics.
Maxwell unified electromagnetics and deduced the speed of electromagnetic waves propagation, that is, the speed of light is a constant, which means that light will only run at a constant speed in a vacuum.
waves will be linked to the medium in our understanding. For example, water waves spread in water, fluctuate water does not move, sounds spread in the air, sound waves, air will not move in the direction of propagation with sound waves .
What is the medium for light waves? In electromagnetics, the changing electric field produces a magnetic field, and the changing magnetic field will produce an electric field. According to Maxwell's equation wave speed is only related to the dielectric constant and magnetic permeability constant in space . These two constants only involve space and do not reflect the medium to which the light wave belongs and the corresponding inertia system. If the speed of light is only relative to the absolute space, then the speed of light is absolute. This possibility is too abstract and subverts classical physics, so a large number of scientists have devoted themselves to the wave of finding mediums at speed of light, and they firmly believe that there must be some medium in space.
It is actually not difficult to find evidence of media. You can compare light to a car with a constant speed of C and medium to a road. If the medium does exist, then car C moves relative to the road, but the road is on the earth, and the earth has a revolution speed and also moves in the medium, which is equivalent to the earth carrying the road, and the road carrying the car moving in the medium. Therefore, the speed of light (car C) parallel to earth orbit relative to the medium is not C. If the same direction as the earth's revolution is (C+V), V is the earth's revolution speed, and the reverse direction is (C-V), it is easy to know this.
We emit a beam of light in the direction of the earth's revolution and the direction perpendicular to the rotational speed. The light in the horizontal direction will be "driven" by the earth's revolution, so the "speed change" in the horizontal direction is no longer constant to C, while the light perpendicular to the rotational speed will not be affected by the earth's revolution in the vertical direction.
Figure: Principle of experimental instruments
In order to find the medium, Michaelson and Morey designed an experimental instrument through the above principles, so that the two beams of light travel at the same distance. As a result, it was found that no matter how many experiments were adjusted, it was found that the light reached the end point at the same time. This means that there is no relativity at all at the speed of light in . Whether it is the static and the light source or the wireless movement of the light close to the speed of light, the light they see propagation speed in the vacuum is C, not relative, not superimposed, that is, the absolute speed. The concept of absolute time is broken by
The emergence of absolute speed of
means that absolute time will expire. There is a light in the center of a bus. When the light is turned on and shot towards the front and rear of the car at an absolute speed, it seems that the people on the car will not move relative to the car and themselves, so the light reaches the front and rear of the car at the same time.
For you on the roadside, the speed of light will not overlap with the speed of the car, but the car is moving relative to you, so you will see that the light first reaches the rear of the car and then to the front of the car.
Because you and the car have relative movement , and the simultaneous nature is broken, so the time is not synchronized with , and the time between you and the passenger is relative.
speed time expansion
Back to the problem itself, you and the high-speed spacecraft are relative, traveling the same distance, the astronauts in the spacecraft spend 1 hour, and the time you come to you has passed. Because your measurement time is slow, no matter how fast the people on the spacecraft run, they will lower the speed because the time you measured is too slow. The result of this speed is to do the relative speed in special relativity .
Everything comes from Einstein's inference based on the invariance of the speed of light, that is, the moving clock slows down, the speed and time expands. If you are interested, you can give yourself a few application questions that are suspected to be super-light speed, substitute them into the formula of the special theory of relativity below to calculate, and you will find that even if a person runs 0.01m/s slower than the speed of light on a spacecraft, the relative speed cannot exceed the speed of light.
