Both A and B are moving in opposite directions at the speed of light, is their relative speed faster

Relativistic velocity superposition formula: w=(u+v) (1+uv c 2)

To calculate the velocity w of A with respect to B, it is necessary to know:

1.(see this where A and B move at opposite speeds of light) The velocity of motion of the coordinate system relative to B is u c;

2.The velocity v c of motion of A relative to the coordinate system.

So, the velocity of A relative to B is: w=(c+c) (1+c*c c 2)=c.

Therefore the relative velocity of A and B is still c.

The relative velocity is still the speed of light.

The point is that time is different in these two frames of reference (two beams of light).

The Galileo transform (velocity superposition) is not suitable for high-speed motion.

If you choose each other as references, it is faster-than-light, but not necessarily if you choose other references.

The speed is still the speed of light, because the speed of light in the theory of relativity is that in any frame of reference, the speed of light is always constant.

It cannot be faster than light, because as long as the speed of an object reaches the speed of light, its relative time will stop. He will stop moving in the universe. And the light continues to move, in this case; It was proved impossible for this object to reach the speed of light.

Both A and B are moving in opposite directions at close to the speed of light, and their relative velocity is still less than the speed of light.

False, space-time is inconsistent, there is no relative velocity.

False, within the scope of the current theory, is to think that the speed of light is absolute, that is, the speed of light is unsurpassable. So their relative velocity is still the speed of light.

Because there is no inertial frame that is more complete than the current theory.

Why the speed of light is absolute, this is explained in the special theory of relativity. It is advisable to refer to the special theory of relativity.

Their relative velocity is still the speed of light. Because the frame of reference changes, the velocity is not cumulative.

According to ordinary people's thinking, it should be faster than light, but asking Einstein will be different

The speed has not changed, it is still the speed of light. It's just that time has changed.

In fact, we all actually know that no matter how the speed is superimposed, it is impossible to exceed the speed of light, otherwise, Einstein's theory of relativity would have been overturned long ago, even elementary school students know how to calculate relative velocity in the way of superimposed speed, Einstein certainly would not know, therefore, it is impossible to rely in any form on the assumption that the speed superposition exceeds the speed of light, so why do people always ask such a question, the reason is that they are completely unclear, or do not know that it is impossible to exceed the speed of light.

In fact, it is also quite normal to dwell on this problem, after all, in our school days, at least until our high school years, we used velocity superposition to calculate relative velocity, physics is called the Galilean transform, which is expressed mathematically as v v1 v2. However, the Galilean transform is only applicable to the calculation of the relative velocity of a low-speed world, and behind the Galilean transform is an absolute view of time and space, that is, the time and space in which we live are absolute.

For example, the 1 kilometer in your eyes is exactly the same as the 1 kilometer in my eyes, in the same way, the second in your eyes is the same as the second in my eyes, and because the absolute view of time and space is well suited to our perception of the world around us, we are almost always dominated by the absolute view of time and space. For example, what time we spend each day is the same concept for everyone.

Another example is that the distance from Beijing to Shanghai is about 800 kilometers, and everyone's eyes are 800 kilometers, but all because we live in a low-speed world. If you come to a sub-light world, everything will be very different, the concept of time and space will become very vague and uncertain, the concept of time and space will be different in everyone's eyes, and there will be a lot of differences.

On the question of can two objects move in the opposite direction of the speed of light with relative velocity exceeding the speed of light, here is the explanation for today.

OK. Because if two objects move in the opposite direction of the speed of light, then the relative velocity will be twice the speed of light, so the speed of light can be exceeded.

No, no matter how the speeds are superimposed, it is impossible to exceed the speed of light, otherwise, Einstein's theory of relativity would have been overturned long ago.

It has not been clear from which frame of reference to look at. From the relatively stationary frame of reference, the speed at which these two objects are approaching can of course exceed the speed of light, but if you look at the speed of another object relative to it from the motion frame of one of the moving objects, then you need to use the Lorentz transformation, which will not exceed the speed of light.

No, when the velocity of the object is much less than the speed of light, v=v1+v2, but when the velocity is much less than the speed of light, v=(v1+v2) (1+v1v2 c2).

The relative velocity is superimposed to calculate the relative velocity v=v1+v2, which is called the "Galilean transform" in physics, and then you will immediately think of Einstein's special theory of relativity in advanced physics at the university - objects can only approach the speed of light infinitely, but cannot exceed or equal the speed of light!

Relativistic superposition formula for speed retardation: w=(u+v) (1+uv c 2).

To calculate the speed of A relative to B, you need to know:

See that A and B are moving opposite at the speed of light) coordinate system relative to B.

Speed of movement. is u c;

Armor. Relative coordinate system.

The speed of movement v c.

So, the velocity of A relative to B is: w=(c+c) (1+c*c c 2)=c.

Therefore the relative velocity of A and B is still c.

The speed of light is a very important physical quantity in physics, and human understanding and research on the speed of light have promoted the rapid development of physics. In 1905, Einstein gave the special theory of relativity, and mankind recognized that the speed of light is the limit of the speed of matter movement or energy transfer, and also the limit of the speed of information transmission.

It is important to realize here that the theory of relativity does not limit the velocity, but the speed of the movement of matter. Many faster-than-light phenomena have been discovered, such as the well-known faster-than-light with phase speed, the faster-than-luminal velocity in anomalous dispersion, the faster-than-luminal velocity in quantum entanglement, and the faster-than-luminal velocity in the expansion of the universe. All the faster-than-light discoveries by humans do not violate the theory of relativity, because none of these superluminal speeds can make matter move faster than the speed of light, nor can they transmit information with such superluminal speeds.

Here I can introduce you to a simple faster-than-light experiment, which can be completed with a laser pointer or flashlight, or even directly with a thought experiment to illustrate the problem.

When a laser beam is directed at the Moon 380,000 kilometers away, a spot of light is formed on the Moon. Then turn your arm sharply to project the laser onto the ground, and a spot of light will appear on the ground. Assuming that it takes seconds to rotate the arm, it is as if the spot has traveled 380,000 kilometers to the surface of the earth in a second time.

To understand this more clearly, imagine a bridge between the Earth and the Moon, and the laser pointer is pointed at the bridge from the Moon to the Earth.

In this simple experiment, the speed of light appeared, dividing 380,000 kilometers by seconds to get a speed of 760,000 kilometers per second. But this speed is meaningless, because the speed of energy here is not faster than the speed of light, and the speed of information transmission is not faster than the speed of light. The spots that appear on the ground are not moved from the moon at all, but are later projected on the ground by the laser pointer.

If you think about it, you can also see that the spots did not move to Earth along the bridge that connects the Earth and the Moon. It takes more than 1 second for light to travel from the Earth to the Moon, and the spot on the Moon is still on the Moon for the second you turn your arm and for some time afterward. The spots on the Moon were still there when they appeared on Earth.

Because the theory of relativity can explain any phenomenon in the world, this discovery is just a phenomenon in the universe.

Since none of these superluminal speeds can make matter move faster than the speed of light, nor can they transmit information at such superluminal speeds, it is not contrary to the conclusion of the theory of relativity.

In fact, the existence of this phenomenon does not challenge the status of fundamental physics to a certain extent, and is still included in the scope of relativity.

I'll say them one by one.

Einstein's theory is that if an object is moving faster than the speed of light, then time is stationary for it, or time goes backwards. "First of all, this is not his old man's theory!

Q1: No. The theory of relativity has two basic assumptions1

The principle of invariance of the speed of light 2The principle of special relativity (all laws of physics are equivalent in an inertial frame of reference, i.e., have the same form) The theory of relativity is so concise that everything else can be deduced from this. What length shrinks, time expands, mass expands.

Q2: Prove special relativity wrong? Hehe, just find the one that moves faster than the speed of light (note that there is information, and the substance that does not carry information is allowed to exceed the speed of light, which is not contrary to Einstein's old man), "no object will move faster than the speed of light" is just an assumption.

So far, no one has overturned it.

Q3: There are many mistakes in junior high school physics, and we should treat them critically. The meaning expressed in this sentence is correct, but it is a bit problematic.

As long as the resultant external force on an object is zero and has a certain initial velocity, it can always move in a straight line at a uniform velocity. This can never be proven exactly!

Okay, let's move on. All physical formulas are an approximate assumption, only to a different degree. It is impossible for all physical quantities to be precisely defined.

Physics is not like mathematics, physics is not rigorous and imprecise (of course, this error is very small, very small). In fact, these theories can never be proved correct, and theories can only be corrected to be wrong. There is no absolute right or wrong, only relative right and wrong.

All in all, a theory that can explain existing phenomena within a certain range, can make predictions, and can benefit mankind, hehe, this is a good theory. Don't care if it's hypothetical.

When an object exceeds the speed of light ...

Faster-than-light, special relativity will lead to a lot of troublesome jumbled conclusions. So if you want to make special relativity correct, you can't go faster than the speed of light. To the extent that the special theory of relativity allows, we can infer from the phenomena when an object approaches the speed of light that time is frozen relative to the observer on the ground when the speed of light is reached...

As for the speed of light, the special theory of relativity is completely messed up, and nothing can be done in **...

As for the hypothetical experiment of uniform linear motion, it is speculated by our "experience" ...

In fact, it is not possible to test it rigorously by experiment. Let's just say that from experience, it's very, very, very, very likely to be true.

Physical theories can be proved by mathematical formulas and operations, one by the derivation of theories and the other by extrapolation, since they are all theories, they have not been proved by practice. The three questions you raised are still in the theoretical stage, so they don't need to be proved and can't be proven, in terms of current technology.

Einstein never said this to you, and Einstein never approved of turning back time. The special theory of relativity only gives time dilation and a shortening of length. Time dilation and time rewind are not the same thing.

Nothing is faster than the speed of light, and that's because of the relationship between mass and energy. Mass and energy are two sides of the same coin, which means that if the energy of an object increases, so does the mass. Crucially, to increase the velocity of an object is to increase its energy, and the faster the velocity, the greater the mass of the object.

Theoretically, when an object's velocity reaches the speed of light, its mass will become infinite, which requires infinite energy to do, but no matter how hard you try, no one can have infinite energy, which is why no object can reach the speed of light.

So it is impossible for any object with mass to move faster than the speed of light, but the premise here is that there is mass, which is not applicable to objects without mass. Just as Newton's three laws are only suitable for classical physics, Kepler's three laws are suitable for the macroscopic world, and quantum physics is suitable for quantum motion, their scope of use is different, and there may be crossovers, but they cannot be generalized. Just as Aristotle proposed that force is the cause of maintaining the motion of objects, it can solve practical problems under the conditions and realities of the time, so people think it is correct, but now we all know that it is not true.

Another example is Newton's classical physics, which cannot explain macroscopic high-speed motion and microscopic, so it is not completely correct, but we are still applying it in daily life, because the range of use meets our current needs, and we can ignore some factors that have little impact on the result, such as mass will change with the change of velocity, because the influence of velocity on the result under classical physics is too small. But when the velocity is high, this result becomes impossible to ignore, because it is no longer the thousandth in classical physics.

1. 1 in 10,000, and it may have reached a few percent, a few tenths. Under our current physical framework, these are all true, but in countless years, new theories may emerge to overturn existing theories, and it can only be said that the current theories are valid under the current view of time and space.