What is dark matter? This question is quite complicated to say. We live in water like fish, and we live in dark matter; Fish don't know what water is, and neither do we know what space is.

What is dark matter? At present, the standard explanation is that dark matter is an invisible substance that may exist in the universe. It may be the main component of cosmic matter, but it does not belong to any known matter that constitutes visible celestial bodies. The phenomenon of suspected violation of Newton's gravity found in a large number of astronomical observations can be well explained on the premise of assuming the existence of dark matter. Modern astronomy shows that dark matter may exist in a large number of galaxies, star clusters and the universe, and its mass is far greater than the sum of all visible celestial bodies in the universe through the observation of celestial movement, Newton's gravitational phenomenon, gravitational lens effect, the formation of large-scale structure of the universe and microwave background radiation. The question is, why can't the ubiquitous substances in space be sure what they are? We must start from scratch.

As early as 1922, astronomers found that according to Newton's law of universal gravitation and Kepler's law, if the mass of a galaxy is mainly concentrated on the visible stars at the core of the galaxy, then the speed of the stars outside the galaxy (using high-precision spectral measurement technology, the relationship between the rotation speed and the distance of the peripheral stars far away from the core of the galaxy can be detected. ) will decrease with distance. However, the observation results show that the rotation speed of the stars in the outer region of the galaxy is much faster than that predicted by Kepler's law, which corresponds to the large mass-light ratio of the galaxy (the mass-light ratio of the galaxy is usually in the unit of solar mass and luminosity). Through the observation of binary systems, such as galaxy clusters, the mass-light ratios of various types of galaxies can be obtained. This means that the mass of galaxies is many times larger than the total mass of "visible" luminous stars. If the gravitational force generated by the mass of the visible stars in the galaxy alone cannot bind the stars in the cluster, then at the current rotation speed of the galaxy, the galaxy will fall apart due to centrifugal force (excluding the repulsive force of dark energy).

Simply put, according to the mass (mass-light ratio estimation) of the luminous stars in the galaxy, the galaxy will be divided at the current speed, so either Newton's law of gravity is wrong, or the actual mass of the galaxy is 100 times larger than the current estimated mass. These "invisible" substances do not emit light and cannot be observed, so they are called dark matter. Excluding non-luminous stars (such as black holes, neutron stars, aging white dwarfs, brown dwarfs and planets), it is estimated that about 94% of the universe is dark matter.

What does dark matter look like? Because dark matter is not directly detected, there is only indirect evidence:

1. Galaxy rotation curve and dispersion velocity distribution, the speed of celestial bodies around the center of the galaxy should be slower than that around the center, which implies that there are huge invisible substances in these galaxies.

2. Gravitational lens effect. Light will bend when it passes through a massive galaxy cluster, similar to the lens principle in optics. People suspect that dark matter is the "substance" that constitutes this gravitational lens.

3. By carefully observing the anisotropy of microwave background radiation in the universe, the total amount of dark matter in the universe can be determined. Based on this, it is speculated that 26.8% of the total energy of the universe is contributed by dark matter, only 4.9% is composed of celestial conventional matter and interstellar gas, and the remaining 68.3% is dark energy that promotes the accelerated expansion of the universe (please note that there are different opinions).

Detection methods for finding dark matter can be divided into three categories:

1. Direct detection, which detects the direct interaction between dark matter particles and substances in the detector.

2. Indirect detection, looking for the signal that dark matter itself decays or annihilates in the universe to produce ordinary matter.

3. Accelerator detection, using particle collider to artificially generate dark matter particles.

Guess the nature of dark matter:

1 dark matter participates in gravitational interaction, but the mass of a single dark matter particle is still uncertain.

2. Dark matter should be highly stable.

3. Dark matter basically does not participate in electromagnetic interaction, nor does it participate in strong-weak interaction. The interaction with photons must be so weak that dark matter hardly emits light.

4. The motion speed of dark matter should be much lower than the speed of light, that is, "cold dark matter".

According to the viewpoint of quantum mechanics, dark matter candidates include weakly interacting mass particles (WIMP), including neutral partners, Kaluza-Klein excited state particles, T-odd particles, inert neutrinos and axions.

All right, it's time to wrap it up.

According to the current mainstream view, the universe is mainly composed of dark matter! Hey ~? Don't be surprised, it's a fact. Dark matter accounts for 85%~90% of the total mass of the universe (opinions vary), and visible matter only accounts for a small part, so the conclusion is that the main body of the universe is composed of "invisible dark matter". Do you find it ironic? What is even more surprising is that the matter that should be ubiquitous in the universe (and gravitons, neutrinos, etc.). ) I can't find it anywhere. What's the matter?

The situation is very strange now. On the one hand, it is contradictory to think that space is full of ubiquitous dark matter. In fact, the current mainstream physical theories are all particle theories, in other words, the current mainstream theories all think that space is an empty vacuum (at least, these theories all think that space is a vacuum at the beginning of their establishment).

The problem is that dark matter is there. Believe it or not, it is there, neither running nor hiding.

Can we change our minds? Is there a theory based on non-vacuum? Of course, this theory is the classical physics on which modern science and technology still depend.

180 1 year, Thomas Young's double-slit interference experiment laid the foundation of wave theory. After the victory of the second wave-particle battle, ether exists as an absolute frame of reference (absolute space), matter moves absolutely relative to ether space, electromagnetic wave is the transverse vibration of ether, and classical electrodynamics is based on ether. Please note that the space of classical physics is three-dimensional absolute space plus one-dimensional independent time, that is, trinity time and space. Absolute space (ether), absolute motion and absolute time constitute the logical basis of classical physics.

1887 Michelson-Morey experiment shows that the speed of light and the propagation direction of two beams of light in vertical and horizontal directions have not changed, which now means that space is not absolutely static. But before the theory of relativity was put forward, ether was not abandoned because of this experiment, because apart from the imperfect experimental design, it was important that there were three different ether hypotheses at that time, and the absolutely static ether hypothesis was only one of them.

1. "Ether drag hypothesis", also known as "Ether drift hypothesis". Ether exists as an absolute frame of reference. Ether is everywhere, weightless and absolutely static. The etheric space will have relative motion with the moving stars. Therefore, the "etheric wind" of 30 kilometers per second should be measured on the earth.

2. "Ethernet partial traction hypothesis". Fresnel thinks that the ether is absolutely stationary, but when an object moves relative to the reference frame of the ether, only the part of the ether inside it that is beyond the vacuum is driven by the object.

3. The "ether complete drag hypothesis". George Stokes, a British physicist, believes that instead of assuming that the star can completely drag a part of the ether, the ether near the surface of the object has a gradual deceleration region, and the star drags the surrounding part of the ether to move together, while the ether in the space far away from the star is completely static, it is better to divide it into two parts: fixed (ether drift hypothesis) and movable (ether partial traction hypothesis). That is, on the surface of the earth, the speed of ether is the same as that of the earth, that is, the earth pulls this part of ether completely. Only at a certain height from the earth's surface can the ether be considered static. [Introduction to Einstein's Special and General Relativity, page 17] Therefore, there is no relative motion between the etheric space near the surface of the earth and the earth (please note! )。

The question is, why does Michelson-Morey experiment falsify the ether in the current textbook?

Human nature is very interesting. People always believe what they want to believe, not the facts. This is confirmatory prejudice. Confirmatory bias refers to the phenomenon that individuals, including scholars, tend to look for information that can support their original views and ignore unfavorable or contradictory information to support their views. For example:

1. Michelson-Morey experiment is based on Fizeau experiment. The Fizeau experiment in 1859 proved that the speed of light and the speed of space medium are superimposed or decreased. Therefore, Michelson-Morey experiment will judge whether there is relative motion between the earth's surface and space by measuring the difference of light speed between two parallel and vertical beams. If the speed of light does not overlap or decrease with the speed of motion of the space medium, then Michelson-Morey experiment cannot conclude that there is no "etheric wind". However, people completely ignored the conclusion of Fizeau's experiment. The reason is that if we admit the conclusion of Fizeau's experiment, that is, prove that the speed of light will overlap or decrease with the speed of motion of space media, then we will directly falsify the principle of constant speed of light! ! ! Therefore, the Fizeau experiment is now vague, only that the Fizeau experiment verifies Fresnel's "Ether Partial Traction Hypothesis", and the conclusion does not explain whether the speed of light will overlap or decrease with the speed of motion of space media. Most people don't know what the conclusion of this experiment is.

2. Were the students surprised that the Michelson-Morey experiment was conducted in the basement of Case Institute of Technology? Unless the earth is a hollow structure, as Thomas Young thought, and the ether "passes through the hollow structure of the earth like the wind passes through the grove" and reaches the basement, it is impossible to measure whether there is "ether wind" in the basement, which is as ridiculous as measuring whether there is wind in a sealed jar. In fact, most people have no idea that the Michelson-Morey experiment was conducted in the basement, so it's hard to believe that they didn't deliberately hide the truth.

3. Michelson's Mo-ray experiment can only falsify the "Ether Traction Hypothesis", but not Fresnel's "Ether Partial Traction Hypothesis", let alone Stokes' "Ether Complete Traction Hypothesis". However, Stokes and his "Ether Total Traction Hypothesis" have been forgotten, as if "Ether Total Traction Hypothesis" never existed. In most related books, there is only the "Ether Traction Hypothesis" but not the "Ether Total Traction Hypothesis".

Why do some people think that ether must be wrong?

As we all know, particle theory and wave theory have been debated for more than 300 years. The wave of wave theory must have vibration medium, and gravity, electromagnetic force, weak nuclear force and strong nuclear force all need space medium to transmit. The theory of particle theory can only be based on empty vacuum, because it is impossible for any inertial particle to maintain a uniform speed because of resistance in non-vacuum space. Therefore, the focus of debate between particle theory and wave theory is whether space is an empty vacuum or composed of matter-ether, which is related to the right and wrong of particle theory (relativity and quantum mechanics) and wave theory (and now string theory based on vacuum), and also to the big problem of life and death theory of the two schools.

The classical electrodynamics theory of classical physics is based on ether, and electromagnetic wave is the transverse vibration of ether. At present, all human science and technology are based on classical physics, and the interpretation of objective nature by classical physics has become our scientific common sense. The galilean transformation of classical physics is that an object is equivalent to space motion, and the ether is this absolute space. Einstein thought that space is an empty vacuum, and objects (inertial systems) only move with each other as reference objects, not with (absolute) space as reference objects. This is the so-called Lorentz transformation, which is based on a vacuum (in fact, it has nothing to do with Lorenz, who is a supporter of the etheric space). If space is ether, then the relative motion can only be galilean transformation, not Lorentz transformation based on vacuum. So for the theory of particle theory, space must be empty. If space is made of any substance, then the particle theory cannot be self-consistent! All particle theories based on vacuum will fall apart.

As the saying goes, where there are people, there are rivers and lakes, and where there are rivers and lakes, there will be sects. If there are sects, the interests of sects will be higher than justice. Physics is also not exempt from customs. History is written by winners' books. With the acceptance of special relativity and general relativity by physicists and ordinary people, especially the rise of quantum mechanics based on vacuum, people gradually accepted the concept of vacuum, and particle theory gradually occupied a dominant position. Thus, Michelson-Morey experiment falsifies the ether hypothesis in textbooks, not just the "ether drag hypothesis" which is closest to the truth.

Interestingly, even Einstein, the "Jianghu tycoon", failed to make a comeback. Einstein began to reflect on the essence of space in 1920, and put forward "general relativity ether", but this "general relativity ether" was resisted by the whole physics circle. Although the devil was released by Einstein himself, from the point of view that he overthrew his own point of view and put forward "the ether of general relativity", Einstein still has the belief of seeking truth from facts in his bones, and his scientific attitude deserves respect. It's a pity that he can't stop the whole scientific trend. Many times, the interests of sects are above everything else. Therefore, the accusation that Ether must be abandoned is "unwarranted".

Did vacuum say win? Of course not! Because there are too many logical loopholes in particle theory, just like a broken coat, it has been broken to the point where it can't be broken any more.

As we know, dark matter is also matter, but matter will attract and be attracted by other matter ("dark matter halo" proves that dark matter will be attracted by the gravity of massive stars). The problem is that if space is full of dark matter, then the motion of stars and dark matter will produce relative motion. We want to measure the "dark matter wind" of 30 kilometers per second on the earth. Why didn't anyone test it? If we follow the Michelson-Morey experimental method, the experiment will also conclude that there is no dark matter. Isn't it interesting?

If space is made of dark matter or any other matter, it will produce space resistance, and the speed of stars will gradually slow down because of friction with dark matter!

If space is not an empty vacuum, then any inertial particles in this space will be unable to maintain a uniform speed because of resistance, such as photons. Particle theory is incompatible with ether! Particle theory is as incompatible as dark matter!

The trouble is that more and more evidence proves that there is something in space instead of an empty vacuum, and space is made of matter, which is a disaster for particle theory. How? There are many smart people. Quite simply, the matter that fills the space will never be characterized. Without qualitative things, there will be no definite attributes. Although it is called dark matter, few people regard it as real matter, which avoids the fact that space is made of matter (an extension of matter). What's the matter, smart or not? Just ask if you are convinced.

In fact, there is no verifiable evidence that ether does not exist except Michelson-Morey experiment, which can falsify the "Ether Drag Hypothesis". If there is other evidence, please give an example! ! ! However, Michelson-Morey experiment can't deny Stokes' hypothesis of "complete traction of ether", let alone the ether. Since there is no evidence to falsify the ether, what is the reason to abandon the ether? We should not forget Occam's razor principle: don't add entities unless necessary. Turning a blind eye to the ether that has existed for hundreds of years, but creating a new substance out of thin air will only complicate simple things and make the truth more confusing.

The weakness of human nature tells us that it is the most difficult thing in the world to make people admit their mistakes. As Planck said: "As usual, a new scientific truth cannot be achieved by persuading opponents and waiting for them to express their opinions and say that they have benefited a lot." On the contrary, it can only be implemented when the opponents gradually die and the new generation begins to be familiar with the truth. "This is Planck's law. The existence of dark matter proves that space is not empty, and the existence of dark matter can also prove that particle theory is wrong. The game of stealing clocks can only achieve the purpose of deceiving oneself and others in a short time. Time is the greatest enemy of lies, and logic is the greatest enemy of ignorance. We have to ask why quantum has wave-particle duality! When is quantum a particle and when is it a wave? The duality of wave and particle is explained, and the secret of micro-world is solved.

Yuval Harari pointed out: "It is good to respect knowledge and listen to the opinions of scholars, but it is dangerous to worship anyone, including scholars. Once a person is regarded as a prophet or authority, he may believe it, and then become arrogant or even crazy. For followers, once they believe that someone is an authority, they will set limits for themselves, stop trying, and only expect idols to tell them the answers and solutions to all problems. Even if the answer is wrong and the method is not good, they will all accept it. " Wisdom begins with doubt, and the real scientific spirit is doubt and criticism.

The ideological achievements accumulated by the sages for thousands of years have nourished our wisdom. They lit up one lighthouse after another, guiding the development direction of mankind. No one's opinion is right, and no one's opinion is useless. Some viewpoints were later proved to be wrong, that is, navigation lights were set in the wrong places to guide the correct channel. The ultimate theory will not be a brand-new theory, but hidden in the existing theory. When we use objective logic as a tool, we can find out the real background of the universe from a complex point of view.

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