Small spiral galaxies found in recent years violate the postulates of the Standard Model of physics, since dark matter in them must not only attract visible matter, but also hold it in place in other ways, according to an article published in the journal MNRAS.
“These mini-spiral galaxies could be a portal that leads us into a world of new physics that transcends the Standard Model and its explanations for dark matter and dark energy. We studied 36 of these galaxies, which is enough to draw statistical conclusions, and found a connection between the structure of ordinary matter that composes stars and gas, and a similar property of its dark "sister", - said Paolo Salucci of the SISSA Institute in Trieste (Italy).
For a long time, scientists believed that the universe consists of the matter that we see, and which forms the basis of all stars, black holes, nebulae, dust clusters and planets. But the first observations of the speed of movement of stars in nearby galaxies showed that the stars on their outskirts move at an impossibly high speed, about 10 times higher than the calculations showed.
The reason for this, according to scientists today, was the so-called dark matter - a mysterious substance, which accounts for about 75% of the mass of matter in the Universe. Typically, each galaxy has about 8-10 times more dark matter than its visible "cousin", and this dark matter holds the stars in place and prevents them from "scattering".
Today, as Salucci says, almost all scientists are convinced of the existence of dark matter, but its properties, in addition to its obvious gravitational influence on galaxies and galaxy clusters, remain a mystery and a subject of controversy among astrophysicists and cosmologists. Most scientists assume that particles of dark matter, the so-called "wimps", are unlikely to interact with visible matter in any other way, except through gravity.
Salucci and his colleagues found the first evidence that this is not the case by observing recently discovered dwarf galaxies in the immediate vicinity of the Milky Way. These galaxies are similar in shape and properties to the Milky Way, but they are tens and even hundreds of times smaller than our Galaxy.
Observations of the movement of stars inside and on the outskirts of three dozen such “mini-galaxies” revealed an incomprehensible phenomenon - it turned out that the shape of dark matter clumps in such stellar metropolises coincided with how the galaxies themselves looked.
For example, if visible matter in a galaxy of a certain mass is concentrated in one place, then dark matter will do the same. Likewise, if the galaxy is strongly "stretched" and the stars in it are located at a great distance from each other, dark matter will assume a similar shape. This is a very powerful effect that cannot be explained using the Standard Model of physics, "explains Salucci.
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As the scientist notes, similar effects exist in larger galaxies, but such a distribution of dark matter in them was explained earlier by astrophysical processes that can be described within the framework of the existing ideas about the structure of the Universe. Further observations of small galaxies, Salucci hopes, will help us understand exactly how the Standard Model is violated and what properties dark matter has.