If you look at the night sky, you can see millions of glowing stars that have different brightnesses. At the same time, scientists suggest that the cosmos can be filled with invisible boson stars, consisting of an exotic form of matter, which does not glow, writes Space.

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According to modern ideas about the Universe, most of the matter in it is dark matter. There is much indirect evidence that this form of matter exists. Scientists believe that dark matter is some as yet undetected particle, but there is no direct evidence of this yet.

For the past 20 years or so, scientists have believed that dark matter is a hypothetical WIMP particle, or weakly interacting massive particle.. It was assumed that this new particle would have about the same mass as the most severe particle in the universe, that is, the true quark. But the WIMP to a large extent remains an invisible particle, because it is extremely rarely interacting with ordinary matter. But a long search for the WIMP particle did not yield results..

Therefore, scientists have suggested that dark matter is a hypothetical yet undetected particle called an axion. This particle was introduced to solve a problem related to the strong interaction, one of the four main forces of nature. Observations show that strong interaction obeys two important symmetries in the universe: charge and parity. This means that if you take strong interaction, change the charges of all particles to opposite values \u200b\u200band look at the reaction in mirror reflection, you get the same result.

But nothing in theory says that the strong force must obey these symmetries. Physicists tried to fix this by adding a new parameter to the equations and setting this parameter equal to zero, but this did not solve the problem. Scientists then decided that perhaps this parameter represented a new quantum field, and interaction with this field would naturally create symmetry. This is an axion that solves the problem of symmetry.

If axions exist, then they are well suited for the role of dark matter, because there should be a lot of them, and they very rarely interact with ordinary matter, if at all. But axions have some other features.

These particles, as physicists believe, are very light. Their mass should be trillions of times less than that of the lightest particle in the Universe - the neutrino.. Therefore, the quantum-wave nature of the axions should manifest the macroscopic scale. Although a wave is also associated with each particle, they usually do not think about it, unless we are talking about subatomic quantum systems. But axions can spread their wavelength throughout the galaxy.

Physicists also believe that axions are bosons. This is a type of particle that can be in the same quantum state. That is, you can fit as many of them as you want into a compact volume.. Thus, bosons are similar to photons, but are different from other particles such as electrons, which can only fit a certain number into a compact volume.

These two properties of axions mean that they are very well compressed to incredibly high density, drawing up their own gravity. Scientists believe that they can create a kind of star. But this star is completely invisible, because it does not emit light and does not interact with anything..

Such stars are called bosonic stars, axion stars and dark stars.. It is believed that they can be the size of a regular star, but can also be so huge that they cover the entire core of the galaxies.

On the one hand, it is extremely difficult to detect a boson star only if it is not in the solar system or does not pass through the Earth so that the axions can notice earthly detectors. On the other hand, bosonic stars can do anything to be discovered.

For example, they can interfere in thermonuclear synthesis in the nuclei of ordinary stars or explode like supernova.

As Focus already wrote, the first photographed black hole in history changes. Scientists used data on a change in the accretion disc of the ultra -massive black hole M87*to draw a conclusion about its orientation and mass.

Focus also wrote that physicists again checked the special theory of relativity of Einstein. To do this, they used the most massive particle in the Universe.