The attempt to confirm the existence of dark matter with a galactic test

The attempt to confirm the existence of dark matter with a galactic test

June 28, 2018 0 By Michael

Together with colleagues from the United States, scientists Bonn University(Germany) applied high-quality complex modeling to create a special test, with the help of which they are going to clarify the question of the existence of so-called dark matter. And if the confirmation of dark matter fails, researchers believe, it will be necessary to make changes to the NewtonianThe law of universal gravitation.(existence of dark matter)

existence of dark matter

Modeling: This image shows the distribution of dark matter (top) and visible stars (bottom). Photo by E. Garaldi, C. Porciani, E. Romano-Díaz / Universität Bonn für die ZOMG Kollaboration

The research team of Professor Cristiano Porciani of the Rhineland-Friedrich-Wilhelm Institute in Bonn and Marcel S. Pavlovski from University of California, Irvinein a recent issue of the scientific journal Physical Review Letters described how a simulation of the distribution of matter in the so-called satellite galaxies was conducted on a supercomputer. In this case we are talking about small galactic dwarfs located nearbyThe Milky Way or The Andromeda Nebula.(existence of dark matter)

Background

The question of the existence of dark matter is one of the most acute problems of modern cosmology. That the so-called dark matter exists, more than 80 years ago the Swiss astronomer Fritz Zwicky suggested. Zwicky determined that galaxies and galactic clusters move so fast that they should be scattered and scattered in different directions. Therefore, he postulated the presence of invisible matter, which due to its mass creates sufficient gravity to prevent the structural destruction of galaxies and galactic clusters. His American colleagueVera Rubin in the 1970s discovered a similar phenomenon in spiral galaxies of the type The Milky Way: they rotate at such a speed that, according to all physical laws, they should have been torn apart by centrifugal force.(existence of dark matter)

Today, most physicists are convinced that mysterious dark matter does not just exist, and even makes up about 80 percent of the mass of the universe. Since it does not interact with light, it can not be seen through telescopes. True, its existence admirably fits into a number of other observations – for example, in the distribution of background radiation, with the help of which the “afterglow” of the Big Bang becomes noticeable. Also, the existence of dark matter explains the location and speed of the origin of galaxies in the universe.

But direct confirmation that such dark matter exists, despite numerous experimental attempts, has so far failed to secure. This gave rise to a hypothesis among astronomers that gravitational forces could probably behave differently than previously thought. Such a theory is abbreviated as MOND (Modified Newton Dynamics). In accordance with it, the attraction between the two masses is only limitedly subordinated to the Newtonian laws. But at very low accelerations, which dominate in galaxies, gravitation becomes much stronger. It is for this reason that galaxies, under the action of their speed of rotation, are not ruptured. Thus, the theory of MOND implies the rejection of such a “galactic glue” in the form of dark matter. A new study provides astronomers the opportunity to test two hypotheses.(existence of dark matter)

During their modeling, the researchers focused on the relationship with the definition of “radial acceleration relation” (RAR), that is, “the dependence of radial acceleration.” “In galaxies, stars move in circular orbits around their center,” reads the press releaseBonn University. “This means that they are subject to acceleration, which forces them to constantly change direction. This is due to the force of gravity of matter in the galaxy. If we take into account only visible matter, the acceleration should be much smaller. The RAR dependence describes the relationship between this value and the actually observed acceleration. And this allows us to look into the structure of the galaxy. “(existence of dark matter)

attempt to confirm

The heavenly sphere shot by the Gaia probe in color. Photo by ESA / Gaia / DPAC

For the first time, scientists modeled the RAR of dwarf galaxies, laying down in conditions that dark matter exists. “The model showed that they, in principle, behave like large galaxies, only much smaller in size,” says Porciani. “But what if there is no dark matter, but does gravity” function “differently than Newton suggested?” Even before that, the working groups had managed to show that the RAR of dwarf galaxies depends to a large extent on removing them from their mother galaxies, while in the presence of dark matter, as follows from the model, such a difference should not be observed. “Therefore, the results of this experiment can be considered as a test for whether dark matter actually exists or not.”(existence of dark matter)

The answer should be given by the space probe ESA Gaia, which from 2013 engaged in a detailed study of the galaxy-satellite and the stars of the Milky Way. But, given the constantly updated data of the Gaia probe, the answer to this question will have to wait at least several years. “With separate disparate measurements, small differences, which we determined by the model, will not be found in practice. For this, the satellite instruments are not accurate enough, “the researchers believe. – “Repeated shooting and recording of the same stars will eventually make more accurate conclusions. And, in the end, this way it will be possible to determine whether dwarf galaxies behave in accordance with the presence of dark matter in them. “

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