What is dark matter? Dark matter (including dark energy) is considered the most challenging subject in universe research. It represents more than 90% of the matter content in the universe, while the matter we can see accounts for less than 10% of the total matter in the universe (about 5 %about). Dark matter cannot be directly observed, but it can interfere with the light waves or gravity emitted by stars, and its presence can be clearly felt. Scientists have proposed various hypotheses about the properties of dark matter, but until now they have not been fully proven.
Decades ago, dark matter was just a theoretical product when it was first proposed, but now we know that dark matter has become an important part of the universe. The total mass of dark matter is 6.3 times that of ordinary matter, accounting for 1/4 of the energy density of the universe. At the same time, more importantly, dark matter dominates the formation of the structure of the universe. The nature of dark matter is still a mystery, but if it is assumed to be a weakly interacting subatomic particle, the resulting large-scale structure of the universe is consistent with observations. However, recent analyzes of the structure of galaxies and sub-galaxies have shown discrepancies between this hypothesis and observations, which also provides a place for a variety of possible dark matter theories. By studying the density, distribution, evolution and environment of small-scale structures, these potential dark matter models can be distinguished, bringing new light to the study of the nature of dark matter.
About 65 years ago, the first evidence of the existence of dark matter was discovered. At that time, Fritz Zavic discovered that galaxies in large galaxy clusters have extremely high motion speeds. Unless the mass of the galaxy cluster is more than 100 times the value calculated based on the number of stars in it, the galaxy cluster cannot be bound at all. live in these galaxies. Observational analysis over the following decades confirmed this. Although nothing was known about the nature of dark matter, by the 1980s it was widely accepted that it accounts for about 20% of the energy density of the universe.
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Dark energy is an invisible energy that can drive the movement of the universe. The movement of all stars and planets in the universe is driven by dark energy. . The reason why dark energy has such great power is that it accounts for about 73% of the structure of the universe and occupies an absolutely dominant position. Dark energy is a major milestone in cosmological research in recent years. There are two main pieces of evidence supporting dark energy. First, a large number of observations of distant supernovae have shown that the expansion of the universe is accelerating. According to Einstein's gravitational field equation, the phenomenon of accelerated expansion infers that there is "dark energy" with negative pressure in the universe. Another piece of evidence comes from recent studies of the microwave background radiation that have accurately measured the total density of matter in the universe. We know that all ordinary matter and dark matter combined only account for about 1/3, so there is still a shortage of about 2/3. This shortage of matter is called dark energy, and its basic characteristic is that it has negative pressure and is almost uniformly distributed or completely unclumped in the universe. Recent WMAP data shows that dark energy accounts for 73% of the total matter in the universe. It is worth noting that for ordinary energy (radiation), baryons and cold dark matter, the pressure is non-negative, so there must be an unknown negative pressure material that dominates the universe today.
The motion of the universe is vortex, so dark energy always appears in the form of vortex motion. Therefore, a vortex field can be formed within the rotation range of dark energy, which we call the dark energy vortex field, or simply the vortex field. We use En to represent the dark energy of the solar system, and Ep to represent the total kinetic energy of matter moving around the center of the solar system. When En=Ep, the vortex field of the solar system is in equilibrium, and it neither expands nor contracts. But when En declines, the vortex field of the solar system will shrink, and all the planets in the solar system will move closer to the sun.
To mention dark energy, we have to first mention another concept closely related to it-dark matter. The reason why it is called dark matter rather than matter is because it is different from ordinary ordinary matter. There is a fundamental difference.
Ordinary matter is those things that can be seen and touched with the eyes or with the help of tools under normal circumstances, ranging from atoms as small as atoms to large stars in the universe, as close as various objects around us and as far away as various galaxies in the depths of the universe. Ordinary matter can always interact with light or partial waves, or can emit light by itself under certain conditions, or refract light, so that people can perceive, see, touch, or measure it with the help of instruments. However, dark matter is just the opposite. It does not interact with light at all, let alone emit light. Because it does not emit light and does not interact with light, it does not reflect, refract or scatter light. That is, they are 100% transparent to all kinds of waves and light! Therefore, dark matter cannot be seen using light in astronomy. Whether it is electromagnetic waves, radio, infrared rays, gamma rays, or X-rays, they are all useless. It is observed by instruments, so in order to distinguish ordinary matter from this special substance, this special substance is called "dark matter".