The constant c does not simply refer to the speed of light, but is a more fundamental geometric prop

The constant c, often thought of as the speed of light, does not simply refer to the speed at which light travels.

You may have heard that the speed of light c in a vacuum is the fastest speed that anything can reach. This is not always true.

This is especially true in some cases where there are so-called "metachronal processes". Asynchronous processes are those that are carefully arranged or orchestrated, in which the causal relationships between the sub-processes occur in their respective pasts. In this case, the information or influence appears to be "faster-than-light" travel, but in fact does not violate the relativistic speed of light limit, since there is no real immediate causal connection between these sub-processes, they are pre-arranged.

It is a misconception to think of the constant c as merely the speed of light. In fact, c represents a more fundamental geometric property of the universe. While we generally think of c as the speed of light, this is only because the physical properties of light make it exactly equal to the speed defined by this geometric property.

Imagine a model train traveling at a certain speed on the tracks, and at the same time, there is a child dragging a toy car with a rope that happens to be moving at the same speed as the model train. This same speed is not because of the characteristics of the toy car itself, but because it is tied to the model train by a rope. Therefore, the speed of a toy car is determined by its relationship to the model train, rather than standing on its own. The same is true for the speed of light. The speed of light is not a unique property of light, but a fundamental property of the universe.

Einstein and light

Albert Einstein is considered the founder of the theory of relativity for his famous 1905 book "On the Electrodynamics of Moving Bodies" (Zur Elektrodynamik Bewegter K Rper).

In analyzing the important findings of the Michelson-Morey experiment, this experiment presents a result that contradicts conventional physics: the speed of light is constant in different frames of reference, which conflicts with the intuitive idea of the addition of velocities in Galileo's theory. Galileo's theory implies that if light is emitted on a moving object, then the speed of light should be the sum of that object's speed and the speed of lightHowever, the experimental results show that the speed of light is actually a fixed value, which is not affected by the motion state of the reference frame.

Before Einstein, physicists such as Hendrik Lorenz and Henri Poincaré had studied this phenomenon. They are theoretically proposed,In order for the speed of light to remain constant across different frames of reference, Maxwell's equations – a set of equations describing the propagation of light waves – need to be converted in a specific way between frames of reference in relative motion。In Maxwell's theory, the speed of light is defined as a constant based on electrostatics and magnetostatics, suggesting that if Maxwell's equations are consistent across different reference frames, then the speed of light should also be constant.

On the question of time and relative motion, Lorentz and Poincaré do not explicitly indicate whether the time coordinate t represents the actual clock time in different reference frames. They came up with a concept of "effective time" to explain their findings, which is different from clock time in the traditional sense.

Although their theory seemed plausible at the time, they did not directly ** an important question: whether clocks in different frames of reference would record different time changes in the case of relative motion. At the heart of the problem is that time may not be absolutely constant, but may vary depending on the state of motion of the observer.

Albert Einstein was the first scientist to fully accept and publicly express this view. He made it clear that in relative motion, the clocks of different observers actually run at different rates. This view became an important part of his theory of relativity, which completely overturned the traditional understanding of time and space. In a nutshell, Einstein's view states that time is relative and can change depending on the relative velocity of the observer.

Physicist Vladimir Ignatowski studied the Lorentz transform in more depth a few years after Einstein published his famous **. The Lorentz transform is a set of mathematical equations that describe how time and space change between observers at different velocities. Ignatowski focused on what the most basic assumptions were that could be derived from these transformations.

His findings show that Galileo's principle of relativity is sufficient to derive the Lorentz transform in itself. Galileo's principle of relativity led to the emergence of a series of Lorentz transforms that are parameterized by an unknown constant c. This suggests that Ignatowski found the exact form of the Lorentz transform, but this constant c needs to be determined experimentally.

If, according to Galileo's line of thought, time is measured in the same way in all frames of reference, then a limit form of the Lorentz transform is obtained if the constant c takes an infinite value. This means that in cases where the speed of light is much greater than the speed of an object, the Lorentz transform can be reduced to a Galilean transform.

The Michelson-Morey experiment played a key role in physics, particularly in revealing the unknown constant c in Ignatowsky's theory. This experiment, which was originally intended to detect "etheric winds", unexpectedly confirmed an important fact:The speed of light is constant across different frames of reference。This finding coincides with the theory proposed by Ignatowsky.

This is "pure coincidence".Maxwell's equations and light were not even considered in Ignatowsky's theory。So the Michelson-Morey experiment has now found something that moves in c. Ignatowsky's theory also suggests that there can only be such a special universal velocity c in the universe. Thus, the Michelson-Morey experiment experimentally confirms the big speculation implied by Maxwell's equations and shows us that we live in a universe with finite c, and it happens to be the speed of light!

Isn't it elegant? I think this is where Einstein began to regret that he didn't pay enough attention to mathematics. Ignatowski's method is embellished with a simple, elegant group theory that ties together several profound questions, rather than Einstein's equations that are almost impossible for modern people to understand.

At least Einstein had some mathematical guidance before he came up with the general theory of relativity, especially from his lifelong mathematician friend Marcel Grossman!

So we should now think of c as the only velocity that is always measured to the same value in all inertial frames of reference, and light is experimentally found to be moving at this speed. Another corollary of the Michelson-Morey experiment when we consider the quantum of light is that the rest mass of the photon is zero.

In physics, there is a relativistic equation.

February** Dynamic Incentive Program correlates the energy, momentum, and rest mass of particles. This equation shows that the length of a particle's four-dimensional momentum (combined with the concept of relativistic momentum in time and space) in Minkowski space (a way of measuring distances in four-dimensional space) is equivalent to the particle's energy in its stationary frame of reference. This reveals how energy, mass, and momentum are interrelated in the theory of relativity.

Photons live on cones of light, they do not have a stationary frame of reference, and their total energy is completely contained in the kinetic energy.

Light is not unique

In the last decade, it has been experimentally verified by scientific discoveries that the constant c, often thought of as the speed of light, is actually a cosmic constant that is more fundamental than light itself. This has been clearly experimentally demonstrated over the past decade, and especially since the observation of the GW 170817 gravitational wave event in 2017. This event is that gravitational waves are observed to be the same as the speed of light, verifying that gravitational waves also propagate at velocity c. This discovery is significant in the physics community, as it not only confirms ** in general relativity, but also emphasizes the status of the speed of light c as a fundamental and universal speed in the universe.

On August 17, 2017, an astronomically important event occurred. The Ligo Gravitational-Wave Detection Program in the United States and the Virgo Observatory in Europe captured a strong gravitational-wave event from the NGC 4993 galaxy, which is believed to be direct evidence of the merger of two neutron stars. In these two neutron stars there is a merger of about 1Seven seconds later, the Fermi and Integral gamma-ray telescopes in Earth orbit detected gamma-ray bursts from the same celestial region.

The signal source is 1When two neutron stars merge 4.4 billion light-years away, the gravitational wave signal is first acquired, followed by 1After 7 seconds, a gamma-ray burst of the same** was detected. This brief time difference is not in the same way as the whole of 1At a distance of 4.4 billion light-years, it provides an impressive evidence that the speed of light and the speed of gravitational waves coincide. Specifically, this 1A delay of 7 seconds is an extremely small percentage of the total distance traveled, and its accuracy can be as accurate as a quarter of 10 to the power of 16. This value shows that this delay is almost negligible on such a large scale of time and distance, demonstrating a high degree of accuracy of the observation.

But what's even more impressive is that when analyzing the merger event of the two neutron stars, astrophysicists made precise calculations to determine the time it would take for light to escape from the dense mass produced by the merger, known as the debris fog. They found that almost all of the 17 seconds delay time – more than 16 seconds – all can be interpreted in this way. This means that only about a tenth of a second of this delay between the gravitational wave signal and the subsequent detected gamma-ray burst remains unexplained.

According to the general theory of relativity, gravitational waves should propagate at the speed of light. Therefore, when the experimental results confirmed this, the global physics community did not show much surprise, because it was in line with theoretical expectations. But for the individual observer, the scientific discovery still has a profound emotional impact. Although this outcome may be foreseeable in the field of science, it has special implications for individuals.

This discovery is not just a validation of a known scientific theory, but also a confirmation of the speed of light c as a fundamental and universal principle in the universe. This understanding goes beyond the speed of light as the speed of propagation in a particular physical process, but instead reveals its importance as a fundamental property of the universe.