There are two main models of dark energy: cosmological constant (that is, constant energy density and uniform whole space) and essence (a change of energy density in the field of spatio-temporal dynamics). In order to distinguish these two kinds of high-precision measurements, it may be necessary to have a deeper understanding of the expansion and expansion speed of the universe over time. Because of the expansion of the universe, the equation of state of the universe describes the velocity of the measurement equation of dark matter, which is one of the most important problems in observational cosmology today.
Dark energy is invisible, it can promote the energy of motion in the universe, and all the moving stars and planets in the universe are driven by dark energy. Dark energy is so powerful in the structure of the universe because it occupies an absolute dominant position of about 73%. Dark energy is an important milestone in cosmological research in recent years. There are two main types of evidence of dark energy. The first observation of distant supernovae shows that the universe is expanding at an accelerated rate. According to Einstein's gravitational field equation, the pressure inferred from the accelerated expansion phenomenon exists in the negative "dark energy" of the universe. Another evidence comes from the study of microwave background radiation in recent years, which accurately measures the total density of matter in the universe. We know that all ordinary matter and dark matter add up to only about 1/3, so we still need about 2/3. The shortage of matter is called dark energy, and its basic characteristics and negative pressure are almost evenly distributed in space or completely condensed. Recent WMAP data show that 73% of total matter and dark energy are in the universe. It is worth mentioning that the usual energy (radiation), baryon and cold dark matter all have non-negative pressure, so it must be an unknown negative pressure problem, which dominates the universe today.
The universe moves in a vortex, so dark energy always exists in the form of vortex. Therefore, a vortex field can be formed in the rotation range of dark energy, which is called dark energy vortex field, or vortex field for short. The solar system represented by dark energy and the total kinetic energy of matter moving around the center of the solar system. When EN = EP, the solar system with eddy current field is in equilibrium, neither expanding nor contracting. However, when the economy of the solar system declines, the eddy current field will shrink, and all the planets in the solar system will be closer to the sun.
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The dark energy we want to mention is a closely related concept-dark matter, so it is called dark matter, not matter, because it is essentially different from ordinary matter. Generally speaking, ordinary matter is a tool to see the eyes, including things that can be seen and touched, small atoms, stars and galaxies as far away as the universe, and objects as close as the surrounding. Ordinary matter can always interact with light to separate waves, or under certain conditions, it will emit or reflect light, so that it can be perceived, touched or measured by instruments, but when it fades in, on the contrary, it will not happen, because it does not emit light and has no effect, so it will not reflect and fold scattered waves and light. They are 100% transparent body! Astronomy of light means that you can never see whether dark matter is electromagnetic wave, radio or infrared ray, gamma ray and X ray. Everything is useless, so people who are unconscious in Seoul don't think that the current instrument observation. So in order to distinguish it from ordinary matter and this special matter and special matter, it is called "dark matter".
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Compared with dark matter "dark energy", it is strange that there is no "dark energy", and it cannot be called "dark energy", because the basic characteristics of matter are not the only function. Seoul will call it "dark energy". Although it has never been observed, it does exist with the prediction of rational thinking.
Especially in recent years, due to the careful observation of cosmic microwave background radiation (WMAP accurate data, supernova IA data), some surprising observation results and data have been displayed:
A) The age in the universe is1372 billion years.
B) Hubble constant is 0.7 1 km/s/MPa.
C) the universe with the following structure: the total mass of the universe is (100%) ≌ baryon lepton (4.4%)+ hot dark matter (≤2%)+ cold dark matter (≈20%)+ dark energy (73%), and the total density ω 0 =1.000. (This formula means that in the whole universe, the galaxies we see are only about 4% in the whole universe, and the remaining 96% problem is what we can't understand. )
D) "dark energy" will present unprecedented new performance:
The equation of state of matter is expressed by P =Wρn (where P is pressure, ρ is density, W is constant, and N is a certain value), and the common matter W≥0, P≥0, ρ≥0, and the pressure device, the matter is positive.
Dark energy in the equation of state, W =-1. This means that the pressure of "dark energy" is negative and the negative pressure is positive. Our director said: "The concept of stress is easy to understand. The greater the density of matter, the greater the pressure, and the negative pressure is not the usual pressure, but it is usually called "suction". More importantly, the "negative pressure" is so great that ordinary people can't imagine it!
Is this why some substances show this characteristic? Could it be a new material form that humans have not discovered, let alone known? Some fables, in this new physical form, will inevitably produce new breakthroughs and new revolutionary theoretical physics! ! !
About the origin of the concept of dark energy, we must return to Einstein's theory of relativity. 19 15 years, he proposed a set of gravitational equations. The results of equations show that the universe is in eternal motion, which is contrary to Einstein's view that the universe is a fixed point. This result shows that the universe is a static equation. Einstein gave up and introduced a project, now called "Cosmic Constant".
Robert Kirchner is a member of the19971February redshift supernova search team. He is an astronomer at Harvard University. The change of supernova not only shows that the expansion speed of the universe will slow down under its own gravity, but also an invisible mysterious force control, which no one can explain, will promote the future faster. The problem is that no one knows this mysterious power? No one knows why it's fast or not. What is the reason? How did this happen? The carrier of this power, because no one can know, is just a guess: maybe we are living in this universe now, and no one knows. At present, we have not realized the following substances: solid, liquid, gas, and substances in another state after the field state. This substance controls the functions, all properties, existence and mechanism different from ordinary things. Because it is completely different from ordinary matter in the known state, scientists in Seoul call it "dark matter" to distinguish their time. Its functions are called "dark energy" and "dark matter" and "dark matter", which has become one of the biggest scientific mysteries in the world.
Later, people discovered the fact that the universe is expanding through the observation of Hubble Space Telescope. This observation is the "calculation of cosmological constants" before the introduction of the completely consistent gravitational equation. Einstein regretted the news that the universe was actually expanding, so he said, "Introducing the cosmological constant was my biggest mistake! After that, the corner where the cosmological constant was forgotten was followed by an astronomical exploration. The cosmological constant is not only zero, but also does not mean that it tends to infinity, which shows that there are "great" things in the universe, because the cosmological constant means "dark energy". In recent years, scientists have repeatedly confirmed through various observations and calculations that dark energy does account for about 73%, while dark matter accounts for about 23% and ordinary matter only accounts for 4%. This is an amazing number. The news shows that 96% of us now know the universe (57 Nobel Prize winners Li Zhengdao even have only 4% of things that exceed 99%) because we know it. The objective existence of dark matter and dark energy, Li Zhengdao, winner of the 57-year Nobel Prize in Physics, challenged the viewpoint of physics in his book "Space is limited, and I am not going to elaborate on this grand event".
At the beginning of the new century, the National Research Council of the United States published a research report entitled Quarks and the Universe: 1 1 Major Scientific Issues in the New Century. Scientists report that dark matter and dark energy should be the properties of "dark matter" and "dark energy" in the most important astronomical research in the next few decades. The report lists 1 1 independent.
The materials collected by NASA's orbiting Wilkinson microwave exploration satellite also prove that supernovae have the same change. The significance of these changes really makes scientists feel uneasy, because it will indicate that theorists such as Einstein and Hawking may have a wrong influence, and determine the forces of the universe as unknown forces, such as gravity and gravitation, but as "dark energy" and "dark matter" in the form of "cosmological constants".
So this is that dark energy is more like air to people in the universe or fish in the sea, so the physical background and superconductor of the Seoul universe behave more like a vacuum, so it is also called "dark energy" vacuum "vacuum" Is dark energy "vacuum energy"? If vacuum is really "dark energy", then you should have all the basic properties and characteristics of energy-force. It can be seen that the characteristics of vacuum force and the essence of "dark energy" force have become prerequisites for vacuum.
To sum up, we can see that all contradictions are concentrated in a vacuum. Do they have the attribute of power? If vacuum is proved to have the property of power, then the vacuum cleaner force becomes an independent gravitational force, electromagnetic force, a powerful fifth force in nature and a weak force, and then the "fifth force" of cosmology is abandoned in the history of vacuum physics. "Ether" is actually a vacuum with some effect. Vacuum occupies more than 96% of the market share. The whole universe and the mysterious energy that controls the whole universe-"dark energy", all powerful realities of vacuum are vertically famous. So does the attribute of Seoul vacuum have the power to become the core of this paper, so is the vacuum really or really a power attribute? If so, how to show it and reveal it?
As we all know, physics itself is a science based on experiments. From Galileo's Leaning Tower Pisa experiment Michelson-Morey experiment and various high-tech and high-energy physical particle experiments, it is shown that all experimental methods occupy a very important position and play an important role in physics. Behind every new theory, there must be a solid experiment to support a new experimental phenomenon and a new theoretical system, so experiment is the way to discover and confirm the properties of vacuum force.
On the other hand, the decoupling of dark matter that is not coupled with radiation is magnified many times before it fluctuates slightly. Decoupling into a group of ordinary matter, dark matter begins to attract ordinary matter, and then forms the observed structure. This requires an initial fluctuation, but the amplitude is very, very small. The substance here is named because it is a kind of cold dark matter with non-thermal motion and non-relativistic particles.
Before acknowledging the effectiveness of this model, explaining the effectiveness of this model is the last important thing. For the small disturbance (fluctuation) mentioned above, in order to predict its gravitational effect at different wavelengths, the small disturbance spectrum must have a special form. Therefore, the initial density fluctuation should be independently scaled. That is, if the energy distribution is a series of sine waves with different wavelengths, then the amplitudes of all sine waves should be the same. Inflation theory provides a good dynamic mechanism for its success, forming such a small disturbance spectrum (spectral index n = 1). The observation of WMAP confirmed that the predicted and observed results were n = 0.99±0.04.
However, if we don't understand the nature of dark matter, we can't say that we want to understand the universe. Now we know two kinds of dark matter-neutrinos and black holes. But the total contribution of their dark matter is very small, and most of the dark matter is still unknown. Here, we will discuss the possible candidate dark matter, which is caused by the formation of structure, and how to integrate particle detectors and astronomical observations to reveal the properties of dark matter.
The most promising dark matter candidate
After a long time, the basic particles of the most promising dark matter hypothesis have the characteristics of long life, low temperature and no collision. Longevity means that the universe it lives in must be as old as it is today, or even longer. Low temperature refers to decoupling non-relativistic particles, only in this way can they cluster quickly under the action of gravity. The joining process takes place in a small range of the Hubble Space Telescope's field of view (the age of the universe and the speed of light of the product). The field of view is very small relative to the present universe, so the mass of the dark matter formed first may be much smaller than that of the Milky Way, and the dark matter halo of the mass is also smaller. With the expansion of the universe and the field of vision of Hubble Space Telescope, the first dark matter halo will merge to form a large structure, and will merge in the large structure to form a larger structure. The result is a system with different structures in quantity and quality, which is consistent with qualitative observation. On the contrary, for relativistic particles, such as neutrinos, in the process of gravitational aggregation of matter, because of its too fast movement, it is impossible to form the structure we observed. Therefore, the contribution of neutrino mass to dark matter density can be ignored. The results of measuring neutrino mass in solar neutrino experiment also support this point. In the absence of collision, the dark matter halo in the interaction section of dark matter particles (dark matter and ordinary matter) is too small to be ignored. These particles only rely on gravity to bind the extensive orbital motion of other laws to the orbital eccentricity of no man's land and dark matter halo.
Low temperature collision-free dark matter (CCDM) is optimistic for several reasons. Firstly, the numerical simulation results of CCDM structure formation are consistent with the observation results. Secondly, weakly interacting massive particles (WIMP), as a special subclass, can well explain its abundance in the universe. If the interaction between particles is weak, they are in thermal equilibrium in the first 1 second of the universe. Later, due to annihilation, it began to get out of balance. According to the estimation of their interaction cross section, the energy density of these substances accounts for about 20% to 30% of the total energy density of the universe. This is consistent with observation. The third reason for CCDM's optimism is that some attractive candidate particles are predicted in some theoretical models.
Which candidate is a neutral, supersymmetric model particle. The theory of overweight and superstring requires that every known fermion supersymmetry theory should have an attached boson (not yet observed), and every boson must have an attached fermion. If supersymmetry and particles are still this day, they will have the same mass. However, due to the spontaneous breaking of supersymmetry in the early universe, today's massive particles have changed. In addition, most supersymmetric particles are unstable, and supersymmetric breaking and attenuation will occur soon. However, one related particle (mass 100 GeV) avoids the lightest decay because of its symmetry. In the simplest model, these particles are electrically neutral and have weak interaction-they are ideal candidates for WIMP. If dark matter constitutes the central temper, then when the earth passes near the dark matter sun, underground detectors will be able to detect these particles. In addition, it must be noted that this detection does not indicate that it is mainly caused by WIMP dark matter. It is still uncertain whether WIMP's experiments are in the majority, and dark matter still accounts for only a small part.
Another candidate is axion, a very light neutral particle (its mass range is 1μeV), which plays an important role in the grand unified theory. Axis, through the action of tiny force, can't be in thermal balance, so it can't explain its abundance in the universe. The axion boson condensed state at low temperature in the universe has been established and the detection work is under way.
A problem of CCDM
Because of the combination of CCDM, the standard model is a special kind of mathematics. Although some parameters have not been accurately determined, we can still test this theory on different scales. Now we can observe the largest China Merchants Bank (thousands of parsec). The observation of CMB shows the original distribution of matter and energy, and the observation results also show that the distribution is almost uniform. From millions of parsec to millions of parsec, the next scale galaxies are distributed to nearly 1000. These scales, theories and observations are in good agreement, which also gives astronomers confidence to extend this model to various scales.
However, on a smaller scale, the scales of the galaxy (KPC) 1Mpc are inconsistent. A few years ago, this inconsistency was obvious, which directly led to the emergence of the key question of whether the current theory is correct. To a great extent, theorists believe that the inconsistency may be due to the inappropriateness of our assumed dark matter characteristics and the inherent problems of the standard model. First of all, for large structures, gravity is dominant, and all calculations are based on Newton and Einstein's law of universal gravitation. On a smaller scale, the role of high temperature and high density materials in fluid mechanics must be included. Secondly, the fluctuation on a large scale is very small, and we have an accurate method that can be quantitatively calculated. However, on the scale of galaxies, the interaction between ordinary matter is very complicated and radiation. Several main problems in a small scale. Substructures may be less common. The number of dark matter halos predicted by CCDM numerical simulation is basically inversely proportional to its mass. Many small dark matter halos caused by dwarf galaxies and gravitational lens effects should be observed, but the viewpoint has not confirmed this. Those dark matter around the Milky Way or other galaxies, when they merge into galaxies, make the originally thin silver disk observe more thickness than it is now.
The density distribution of dark matter halo in the nuclear field is greatly increased, the distance from the center is reduced, and its density is significantly increased, but we have observed that the central regions of a large number of self-gravitation systems are obviously incompatible. It is necessary to observe the core density of gravitational lens and galaxy cluster in the study, which is lower than the calculation results obtained by a large number of dark matter halo models. The dark matter in the core region of ordinary spiral galaxies is even lower than expected, and the same situation also occurs in some galaxies with low surface brightness. For example, the theoretical density uniformity centers of companion galaxies, Milky Way, Tianlong galaxies and dwarf galaxies are in sharp contrast. The size and angular momentum of the silver disk simulated by fluid dynamics are smaller than those observed. If the rotating rod-like structures in many high surface brightness galaxies are stable, their core density needs to be lower than expected.
It is conceivable that in order to solve these increasingly serious problems, it will rely on complex but ordinary astrophysical processes. Traditional explanations have been proposed to explain the structure of the above-mentioned loss phenomenon. Generally speaking, however, the current observational evidence ranges from a huge cluster of galaxies (with a mass greater than 10 15 solar masses) to the smallest dwarf galaxy (with a mass less than 109 solar masses), and the density of contradiction between theoretical prediction and observation is high and low.
Dark energy
What is dark energy, its existence and what does it mean? Scientists are just beginning to try to answer these questions. As a whole, people gradually realize that dark energy is not only an influence on the whole universe, but also seems to manipulate the guiding principles of the evolution of stars, galaxies and galaxy clusters in the process of cosmic residents. I don't know these structures, dark energy, but astronomers have studied their development for decades.
Ironically, dark energy is everywhere, but it is hard to realize its existence. The dark energy of different substances is evenly distributed and will not gather in a certain place. Whether in your kitchen or in interstellar space, the density of dark energy is exactly the same, about 10-26 kg/m3, which is equivalent to the mass of several hydrogen atoms. All the dark energy in asteroids in our solar system has the same mass and almost no influence, which is combined with the "dance" of planets. Only on a large spatial scale and time span can the influence of dark energy be reflected.
From American astronomer Edwin Hubble to the nearest galaxy, observation astronomers all know that all galaxies have flown away at high speed and are getting farther and farther away from us. This speed is proportional to the distance: the farther the galaxy is, the greater the speed of recession (economic recession). The traditional view is that the size of the universe is fixed, but galaxies are moving away from us, but observations have overturned this view. In fact, in the expanding space structure, galaxies are just trapped farther and farther away from us. Another question follows: how does the inflation rate change with time? Scientists have been trying to answer this question for decades. They speculate that the expansion of the universe will be slower and slower, because the gravity of galaxies prevents it from expanding outward. (For the full text, see the third part of Global Science)