The Hubble Orbiting Observatory has taken unusual photographs of large clusters of galaxies whose inhabitants "tremble" as they move around a common center of mass, indicating the presence of unknown properties in the behavior of dark matter, according to an article published in the journal MNRAS.
“We found that the brightest galaxies in such clusters 'quiver', moving around the point where the dark matter has accumulated. This means that the density of dark matter at the center of the cluster is not as high as predicted by current theories, but much lower. All of this suggests that some exotic form of dark matter is present in the central part of the clusters,”said David Harvey of the Federal Polytechnic School in Lausanne, Switzerland.
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 in them at an impossibly high speed, which was about 10 times higher than calculations based on the masses of all the stars in them 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, 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. For a long time, scientists assumed that it was composed of superheavy and "cold" particles - "wimps", which do not manifest themselves in any way, except for attracting visible clusters of matter.
The unsuccessful search for "WIMPs" in the past two decades has led many theorists to believe that dark matter can actually be "light and fluffy" and consist of so-called axions - ultra-light particles similar in mass and properties to neutrinos. Other researchers, in turn, suggest that dark matter can consist of several different components, one or more of which can gradually decay.
Harvey and his colleagues found the first traces of the existence of such exotic forms of dark matter, observing with the help of the Hubble for ten largest galaxy clusters in the immediate vicinity of the Milky Way, whose mass exceeds the Sun's about 100 trillion times.
Scientists were interested in two things - how the galaxies were distributed throughout the cluster as a whole and how the brightest inhabitants of these "star families" moved when new members appeared in them. To reveal these properties of clusters, astronomers calculated the behavior of their virtual counterparts using supercomputers, and then compared how the real photographs and the simulation results matched.
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It turned out that the trajectories of movement of all large and bright galaxies in these ten clusters did not coincide with what the theoretical calculations showed - they constantly "lost their way" and "trembled", revolving around a common center of mass, and did not move strictly in a straight line. as the theory predicted.
Such a tremor, as Harvey and his colleagues now believe, was due to the fact that in the centers of these clusters there are not one, but several "nuclei" of superdense clumps of dark matter. Their existence is not predicted by classical cosmological theories describing the properties of this mysterious substance, and if the discovery of Hubble is confirmed, then for the first time scientists will be able to talk about the discovery of the first real traces of the “new physics”.
