In the narrow sense of the theory, using light as a frame of reference can not explain that an objec

Unswervingly choose D. Special relativity does not allow matter with mass (no matter how small the mass of an electron is, it has mass) to move faster than the speed of light, and if the speed of light is reached, the mass will be added to infinity, so it is impossible to build a speed-of-light or faster-than-light vehicle.

There is now a theory of "tachyons", which are hypothetical subatomic particles that always travel faster than the speed of light. Its mass is an imaginary number, and its velocity will increase infinitely with the dissipation of energy, and when its energy tends to zero, its velocity tends to infinity. Tachyons, once generated, have a velocity greater than the speed of light.

To reduce its speed, it must be supplied with energy. To reduce to the speed of light, it must be supplied with an infinite amount of energy, so it is impossible to reduce its speed to or below the speed of light. However, the existence of tachyns has not been experimentally confirmed so far.

The negative energy of tachyons is a complex issue. Since the appearance of negative energy will mean that any physical system, which is in an unstable state because it may release tachyns indefinitely, the system will increase its own energy indefinitely, leading to the emergence of a perpetual motion machine. What's even more surprising is that even infinitely generating tachyon pairs does not break the law of conservation of energy momentum, nor does it alter the total energy in the vacuum.

In addition, according to the Lorentz transformation, the order of time may be changed during the conversion of tachyons from one coordinate system to another, i.e., time reversal. Therefore, there are not many people who support the tachyon theory at present.

The theory of relativity cannot use light as a frame of reference, otherwise there will be a phenomenon in which matter reaches the speed of light.

Give the third floor a formula for the Lorentz transform: v=(v1-v2) (1-v1v2 c 2). The Galileo transform is approximately true in the macroscopic low-velocity weak gravitational field model, while the Lorentz transform is used in the microscopic high-speed strong gravitational field model.

The Lorentz transform is the basis of the special theory of relativity. When calculating relative velocity with Lorentz transform, we first need to unify the direction of velocity and use one object as a reference object to determine the relative direction of motion of another object. In two objects, the velocity of the object with the same direction of motion and relative motion is positive velocity, and the opposite velocity is negative velocity, the velocity of the object to be observed is v1, the velocity of the reference object is v2, and the speed of light is c.

The speed of light cannot be used as a frame of reference in the theory of relativity, and all inertial frames are below the speed of light.

Since an object with a resting mass cannot accelerate to the speed of light, let alone superluminal speed. And the speed of light is constant, so only d is the correct solution.

c .According to the Galilean transform: v=c+v

Think of a light source frame of reference as a frame of reference that moves at a constant speed to a stationary frame of reference. Then the v observed in the stationary frame of reference is the speed of light (in the positive direction) plus the velocity v (negative direction) of the light source frame relative to the stationary frame of reference, so it is less than the speed of light.

Just as you can't use a field as a frame of reference, you can't use light as a frame of reference. This is a rule, and only such theories apply.

Option d In physics, it is assumed that the mass of a stationary object is 0 and the mass is related to the magnitude of the velocity.

If the Galilean transform is satisfied, then assuming a light source moving at a uniform speed with a velocity of V, the speed of the light emitted directly in front of it is V+C, which does not satisfy the principle of invariance of the speed of light, that is, it is wrong, so the Galilean transform is not satisfied in the special theory of relativity.

According to McCoswell, the basis of electromagnetic theory, the speed of electromagnetic wave propagation (i.e., the speed of light) is only related to some fundamental physical constants, not to the frame of reference.

In order to solve the contradiction between this conclusion and classical mechanics, the Lorentz transform was introduced. It combines three-dimensional space and time into a four-dimensional vector, and different frames of reference are equivalent to translational and rotational transformations. Under this transformation, if an object moves at the speed of light in one frame of reference, then it will still move at the speed of light when transformed into another frame of reference.

Under such transformations, Maxwell's equations can be held simultaneously in different frames of reference.

Einstein's special theory of relativity provides a physical meaning to the Lorentz transform. He believed that at high speeds, the spatial scale would change, so that the velocities could not be added directly, but a factor should be introduced, which was the result of the Lorentz transformation.

At the same time, he also proposed the kinetic theory, which states that the mass of matter increases with velocity. So for an object with a non-zero mass at rest, the energy required to accelerate it to the speed of light is infinite. Whereas, a substance with zero mass at rest will have a non-zero mass when moving at the speed of light.

This is the special theory of relativity.

The constant speed of light is first and foremost experimental. But experiments can't prove that the speed of light never changes. Einstein took it as a hypothesis.

Assuming that the speed of light does not change, what would happen? He then derived the Lorenz transformation and mass-energy interchange formulas.

Other scientists then test these inferences. So far, it's all in line with the theory of relativity.

So the constant speed of light is just an assumption.

I've only read the introduction of the theory of relativity, and I don't understand the esoteric ones, so let's talk about my own understanding.

At the beginning of the introduction to the theory of relativity, a time delay and length contraction are mentioned (you can refer to the book for details).

When approaching the speed of light, time becomes very slow, and a light is a frame of reference, in which time is stationary and its length shrinks infinitely.

In the static timeline, speed is the thing So, light is still the speed of light, but there is no time interval, just like if you take a picture of the athlete who is running, you can't see that the athlete's running speed is the same from the freeze-frame **.

Purely personal understanding.

It doesn't make sense to use light as a frame of reference.

The physical basis for the invariance of the speed of light is Maxwell's equations.

First, based on the constant speed of light, the general theory of relativity is derived.

Using light as a frame of reference has the same effect as using ether as a frame of reference.

The invariance of the speed of light is the nature of the universe, the property of space-time.

If the photon is chosen as the reference frame, then according to the Lorentz inverse transformation, the laws of motion of other objects and the laws of physics can also be obtained.

The invariance of the speed of light is the basis of the theory of relativity, and all the conclusions deduced from it have been verified, for example, the speed of light that we measured, no matter which direction it is emitted, is unchanged, including the verification of macroscopic objects, which is to put a clock on a space shuttle and let him fly around the earth, and let it take it and the clock on the ground to this, and it really travels here and there a little slower. If the object has a velocity, its mass becomes larger, time slows down, its length in relation to our motion becomes shorter, but they themselves see that everything is the same as usual, and they see us as mass, time slows down, etc. If we take a photon as a frame of reference, it will see that our relative velocity is the speed of light, our mass will become larger, our time will stand still, and our world will become a line in the direction of his motion.

The speed of light propagation in a vacuum is a constant regardless of whether it is observed in any inertial frame of reference and does not change with the relative motion of the light source and the frame of reference in which the observer is located. This value is 299,792,458 meter seconds.

This is where the time delay effect ... When the speed is the speed of light, the flow of time in your own frame of reference is zero, and you are still traveling at the speed of light relative to the other beam, and the same is true relative to yourself

According to Einstein's principle of invariance of the speed of light, superluminal speed is unachievable. Principle of invariance of the speed of light: The speed of light in a vacuum is the same for any observer.

The principle of invariance of the speed of light, in the special theory of relativity, refers to the fact that the propagation speed of light in a vacuum is a constant regardless of the inertial frame (inertial frame of reference) in which it is observed, and does not change with the relative motion of the light source and the frame of reference in which the observer is located. This value is 299,792,458

Meter seconds.