Chapter 405: A day recorded in the history of human science (Part 2)
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In the laboratory.
Looking at Lu Chaoyang with a solemn expression.
Xu Yun swallowed hard and turned to look at everyone in the room.
Zhang Han, Tang Fei, Guo Ping, and even Ye Zhi, the tool man in charge of ordering takeout, had solemn expressions mixed with shock.
Then he looked at Lu Chaoyang again, with a hint of hoarseness in his voice:
"Professor Lu, are you telling the truth?"
Lu Chaoyang smiled bitterly when he heard this and handed the document to Xu Yun:
"See for yourself."
Xu Yun lifted off the blanket on his body, took the document, sat up straight and started reading.
"Quadratic divergence parameter 3.445"
"The column diagram orientation is at right angles to the electron parallel orientation"
"The parity difference is 226.5 points/billion."
at last.
Xu Yun's eyes paused on an item labeled U Group.
This project is divided into four columns: U1, SU2, SU3 and SL (2, C).
Among them, SL(2, C) displays [+], and below the U1, SU2 and SU3 columns is
【X】.
See this situation.
Xu Yun's breath suddenly stopped.
Introduced a long time ago.
In the current particle theory, the particles that transmit "force" are all bosons with spins of one or two.
So what boson is transferred is called force.
There are several types of these bosons, so they need to be classified.
The criterion for classification is symmetry, which is expressed mathematically as a group.
Since the theory describing the forces is called a "gauge field theory", these groups are called gauge groups.
Generally speaking.
The bosons discovered so far can be divided into four groups, which correspond to the four basic forces mentioned before.
The U1 group corresponds to electromagnetic force and photon respectively.
The SU2 group corresponds to the weak force, corresponding to W and Z bosons,
The transmission strong interaction corresponding to SU3 corresponds to gluons.
And the SL(2,C) group corresponds to the transfer of gravitational interaction, which corresponds to the graviton.
In addition to gravitons, three other particles have been discovered.
See here.
There may be children's boots who will say that I understand. What Xu Yun and the others discovered was gravitons.
Unfortunately, not really.
Because the graviton will theoretically participate in electromagnetic interactions, and because its spin is 2, the field theory involves a limit energy scale, which is obviously not in line with today's experimental conditions.
So what does this report mean?
The first point to emphasize is
These four groups can coexist in actual situations, that is, a particle can participate in multiple functions at the same time.
Give an example that is not appropriate but easier to understand:
An author is hung up by a reader. The rope has electromagnetic interaction with him, the gravity of the earth has gravitational interaction with him, and the small universe in his body also has weak interaction.
Therefore, when these four groups detect certain particle characteristics, the reports generally show that the effect of a certain column is strong or weak, not 0.
For example, if a particle is in the U1 group, that is, the degree of electromagnetic interaction is relatively weak, it will be represented by [-].
Strong is [+].
If the corresponding behavior does not occur, then it is [X].
All current particles will participate in gravitational interaction, so under the gravitational interaction, that is, under the SL(2, C) group, there will only be [-] or [+].
As for strong and weak forces, you can occasionally see [X].
For example, lepton.
As for the U1 group, which is the column of electromagnetic interaction, only one particle will appear [X].
That's the neutrino.
And just today.
In front of Xu Yun and the others, another brand new U1 group [X] particle appeared.
More importantly.
A solitary point particle, its movement mode is "flickering".
In other words, its kinetic energy is much smaller than the corresponding static energy - this sentence was once explained by a fat man running 100 meters.
On this basis.
Solitary point particles also have the characteristics of electrical neutrality and no static mass definition. In other words, they have no entity in the microscopic world, so they only participate in gravitational interactions.
In the current scientific community, this kind of particle or substance has a special and exclusive name.
Think of this.
Gulu——
Xu Yun swallowed and looked at Lu Chaoyang in shock:
"So, Professor Lu, we discovered a kind of dark matter?"
Lu Chaoyang took a deep breath and nodded vigorously:
"Yes, according to the teacher's results, the probability is infinitely close to 100%."
Xu Yun stared blankly at the document in his hand. After a long time, he sat back down.
Yes
I should have thought of it a long time ago.
Doesn't an undetectable particle meet the definition of dark matter?
Dark matter.
This is something that is widely spread, but many people know little about it.
The prototype of dark matter can be traced back to 1922.
At that time, astronomer Kaptan indirectly inferred that there might be invisible matter surrounding stars through the movement of star systems.
Then in 1933.
Astrophysicist Zwicky used the spectral redshift method to measure the motion speed and state of each star cluster in the Coma galaxy cluster.
It was found that the velocity dispersion of galaxies is too high. If the gravity generated by the visible mass of galaxies alone cannot bind these galaxies into galaxy clusters, these galaxy clusters will fall apart.
However, the real ‘battle for fame’ of dark matter took place in 1970.
At that time, a female professor named Vera Rubin, who had the same name as a well-known rich woman from Qidian, conducted a measurement of the rotation curve of the Andromeda Galaxy, the neighbor of the Milky Way, which is the M31 galaxy.
The so-called galaxy rotation curve refers to the function curve of the rotation speed of stars at a certain distance from the galaxy around the center of the galaxy.
In human terms, it is the revolution speed.
If the gravity of the galaxy is provided only by visible matter, then it can be calculated that the rotation curve should show such an effect:
The farther away the stars are from the center of the galaxy, the slower they should rotate.
However, Vera Rubin discovered when she observed the Andromeda Galaxy.
The actual rotation curve is after a certain distance.
The farther away the stars are from the center of the galaxy, the rotational speed and interior remain almost constant.
What does this mean?
Anyone who has taken high school physics should know this.
at the same distance from the center of the galaxy.
V1 (which is the theoretically slower speed) and V2 (the rotation speed observed by Vera Rubin) have completely different centrifugal forces.
The former is low and the latter is high.
So if the gravity of the galaxy is provided only by visible matter, then theoretically the stars rotating with V2 will be thrown out of the galaxy.
Unless
Those stars are attracted to something unseen and are thus bound to the galaxy.
That is, the actual mass of the galaxy is greater than the mass calculated from observations.
This is the root of all evil in dark matter.
By 2022, there will be a lot of evidence for dark matter.
For example, the total mass of a galaxy (or galaxy cluster) obtained through multiple independent measurement methods is much greater than the mass of ordinary matter in it.
Another example is the observation of the cosmic microwave background radiation.
Another example is the simulation of the number of galaxy clusters formed at different ages of the universe, etc.
Another thing to mention is.
The current method of calculating the mass of galaxies is very mature and does not cause too much error. (See Chapter 281 for specific methods)
so what.
The above situations are real. To explain these anomalies, people have two ways:
One is to adhere to the correctness of the known theory of gravity, that is, the general theory of relativity, but introduce some kind of electrically neutral material to provide an additional source of gravity.
This kind of particle only participates in gravity but does not participate in electromagnetic interaction. It cannot be detected by electromagnetic means, so it is called "dark matter".
The second is not to introduce the concept of dark matter, but to modify the gravity theory so that the revised theory is consistent with astronomical measurement results on the large-scale structure of the universe.
Particle physicists choose option one.
Because after all, introducing new particles is a more economical and tried-and-tested method, and many earlier models introduced were later proven correct, such as the Higgs particle.
But general relativity theorists mostly like option two.
Because I can eat and grow happily again.
Currently, the number of scientists who hold the first view, that is, the existence of dark matter, is much higher than the latter.
For example, our country has launched the Wukong dark matter detection satellite into the sky for exploration. There are also many related projects abroad.
The more accurate statement in the scientific community now is this:
Of the total mass and energy in the universe, only 4.9% is visible matter.
That is to say, the galaxies, nebulae, dust, stars, planets, etc. that we can see only account for 4.9% of the total mass and energy of the universe, and the remaining 95.1% is 26.8% dark matter and 68.3% dark energy - this is not Minkoha, This is a relatively unified view in cosmology today. (For example, this article 10.1126/science.1146676 in "Science" and this article org/10.1093/mnras/staa3016)
But it needs to be clear.
Although there is a lot of theoretical evidence to support the existence of dark matter, the probability of the existence of dark matter is countless times greater than that of 'gravitons' - the countless times here is not an exaggeration, but it is true.
But so far, humans have still not discovered any dark matter that is not a broad concept.
In a sense, this thing is like a black hole:
Everyone knows that black holes exist, but it was not until the Event Horizon Telescope photographed the accretion disk in 2019 that humans actually confirmed the existence of black holes for the first time.
Until then, the physics and astronomy communities could only use phenomena to show the existence of black holes.
The same goes for dark matter.
Before the discovery of neutrino oscillations, the scientific community had always believed that neutrinos were most likely dark matter.
But after the discovery of neutrino oscillations, this possibility was passed.
Because neutrino oscillation proves that neutrinos move relativistically when galaxies are formed in the universe. If they are the main component of dark matter, they will hinder the formation of large-scale structures of galaxies and even the universe, so they cannot be the main component of dark matter.
Neutrinos are now classified as thermal dark matter, which is part of the dark matter that moves at speeds close to the speed of light in a vacuum and does not participate in electromagnetic interactions.
This is just like the theory of evolution has been looking for the standard 'human ape', that is, the evolutionary intermediate between primitive people and apes.
However, no ape could be found after searching and searching, so we had no choice but to classify the chimpanzees into the concepts of "half-step ape", "peak ape perfection" and "can take a hit from the ape without dying".
In other words, it can be included in the hard calculation, but it has no real meaning.
Today, there are only five particle models that theoretically meet the conditions for dark matter:
Weakly interacting massive particles (WIMP),
Axion,
Sterile Neutrinos,
Supermassive particles,
Ultralight vector particles.
The most interesting of these are WIMPs and supermassive particles.
WIMP is also called cold dark matter. If such particles existed, they would have been produced in large quantities at the beginning of the Big Bang.
Then, after the temperature of the universe drops to the mass energy scale of the WIMP particles, they will quickly annihilate each other.
In the end, the remaining part is left to this day and becomes dark matter.
Xu Yun met an old professor at the Academy of Sciences who liked fairy novels very much. He even gave WIMP a nickname that was very fairy-like:
beacon.
This is also the model with the most researchers and the highest topic at present.
As for supermassive particles? They are also called Godzilla particles and ear root particles.
It refers to a type of particles with a mass greater than the inflation energy standard of about 10^13 GeV.
The operating mechanism of this thing is not the point, but once it is discovered, it will be a lot of fun:
Because this thing can be produced through the "freezein" mechanism of annihilation of other hot particles, it is a propagator of gravitons.
So the discovery of supermassive particles is almost a buy-one-get-one-free discovery of gravitons.
Since these five kinds of particles cannot be found so far, the industry also calls this phenomenon "Five Particles".
Of course.
In addition to these five models, primordial black holes are also candidates for celestial-type dark matter.
This kind of black hole is very different from the black hole formed by the collapse of stars. It is not formed by the evolution of astrophysical processes, but is formed directly from the density fluctuations of the very early universe.
Students who have participated in the Big Bang should know this.
In the very early days of the birth of the universe, cosmic inflation brought original density perturbations to the universe.
If the density perturbation in some space-time regions is large enough.
Then as the horizon expands, it will contain enough matter to directly collapse this space-time area into a black hole. This is the so-called primordial black hole.
As everyone knows.
The more massive a black hole is, the slower it evaporates.
It can be seen from calculations that the original black hole with a mass greater than 10^9 tons can still survive to this day after 13.8 billion years of evolution, thus acting as dark matter.
One of the purposes of future space gravitational wave detection experiments, such as LISA or my country's Tai Chi project, is to search for such black holes.
I just didn’t expect it.
Dark matter, which the entire scientific community has been eagerly anticipating, was unexpectedly discovered like this?
This is no less a treasure than the Pirate King.
Now look back carefully along the timeline.
There is no static mass definition, no entity, and no interaction with any particles in non-ground states.
Even during the ground state treatment not long ago.
Xu Yun and others also found that the results of high-energy photons were not obvious and the constant mass distribution was irregular.
There is also one of the important characteristics of dark matter. The kinetic energy is much smaller than the corresponding static energy.
It can be said that.
Except that it has not been determined whether the solitary point particle has been left to this day after 13.8 billion years of evolution.
All the properties previously exhibited by solitary point particles are all standard dark matter characteristics that cannot be more standard!
Should this be said that people have been searching for him for thousands of times, or should it be said that he was unintentionally inserted?
Think of this.
Xu Yun's mind came back to the original formula that originally discovered the solitary point particle and deduced the motion orbit:
4D/B2=4(√(D1D2))2/[2D0]2=√(D1D2)/[D0]=(1-η2)≤1
{qjik}K(Z/t)=∑(jik=S)∏(jik=q)(Xi)(ωj)(rk); (j=0, 1, 2, 3...; i=0, 1, 2, 3…;k=0, 1, 2, 3…)
{qjik}K(Z/t)=[xaK(Z±S±N±p),xbK(Z±S±N±p),…,xpK(Z±S±N±p),…}∈{ DH}K(Z±S±N±p)
(1-ηf2)(Z±3)=[{K(Z±3)√D}/{R}]K(Z±M±N±3)=∑(ji=3)(ηa+ηb+ηc )K(Z±N±3);
(1-η2)(Z±(N=5)±3): (K(Z±3)√120)K/[(1/3)K(8+5+3)]K(Z±1) ≤1(Z±(N=5)±3);
W(x)=(1-η[xy]2)K(Z±S±N±p)/t{0,2}K(Z±S±N±p)/t{W(x0)}K (Z±S±N±p)/t
The original formula can be divided into three parts, or deciphered in stages.
Among them, the orbits of isolated point particles are only the first one-third of the deciphered results, and there are still two-thirds of them that Xu Yun still has no clue about.
It seems so.
The value of that original formula far exceeded Xu Yun's expectations.
In fact, after the 1850 copy ended, Xu Yun had always had a vague confusion in his heart:
Compared with 1850, what I did in 1100 should have a greater impact.
Let alone history.
It changed the demise of the Northern Song Dynasty, expanded China's territory all the way to Europe, and nearly conquered the world.
In terms of science and technology, microscopes and telescopes were invented, unlocking the microscopic realm a thousand years in advance.
But in terms of rewards, the 1100 copy seems to be much inferior to the 1850 copy.
Although the 1100 copy rewards a national fortune, 1850 also rewards the Yongle Grand Ceremony - this thing is not like the Jade Seal, which requires a specific task to be activated, but can be dug out and eaten immediately.
So the two are barely equivalent.
Except for national luck.
The gravity gradient meter, MR technology, hemostatic gelatin, computing power module and microbial battery rewarded in the 1850 copy will undoubtedly exceed the technology rewards in the 1100 copy.
It's just that Xu Yun has never been very clear about the specific judgment logic of halo, so he can only bury this doubt in his heart.
It seems now
Perhaps the most valuable reward of 1100 copies is not technology, but
That original formula was so complex that it was difficult to understand.
Dark matter has been discovered in one-third of it, but what about the remaining two-thirds?
At least from a mathematical perspective.
The difficulty of the last two-thirds is dozens of times higher than that of the first third.
I'm afraid that's the real treasure
It's unclear whether it's possible or even possible to guess that once all the deciphering is completed, gravitons can really be produced?
Of course.
These are Xu Yun's conjectures, without any actual evidence to support them.
Compared to the original formula.
What Xu Yun needs to pay attention to at this time is this lone particle.
If their previous results can be divided into ordinary area one and CNS.
So the discovery of dark matter
I'm afraid it's not as simple as a certain main magazine.
"It breaks the sky" (End of this chapter)