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Dark matter exists: Observations refute alternative explanations



  Dark Matter Exists: The observations that question their presence in galaxies refuted
acceleration as a function of radius in NGC 4455, one of the galaxies studied. Picture credits: Di Paolo et al. changed from the survey SDSS9.

As intriguing as it is mysterious, dark matter is one of the greatest mysteries of astrophysics and cosmology. It is believed to make up 90 percent of the matter in the universe, but its existence has been shown only indirectly and has recently been called into question. New research by SISSA eliminates the recent doubts about the presence of dark matter in galaxies and refutes the empirical relationships in support of alternative theories. The study, published in the Astrophysical Journal also provides new insights into the understanding of the nature of dark matter and its relation to ordinary matter.

From the expansion of the universe to the motion of stars in galaxies, there are many phenomena that can not be explained by the presence of baryon matter alone. The force of matter created by matter is not enough to explain the observable effects of gravity. This had led to the theory of the existence of undetectable dark matter and the idea that galaxies are embedded in their spherical halo.

"Three years ago, some colleagues at Case Western Reserve University questioned our understanding of the universe and the universe of the in-depth work of many researchers who raise doubts about the existence of dark matter in galaxies," explains Chiara Di Paolo, Ph.D. Astrophysics at SISSA. "By analyzing the rotation curves of 1

53 galaxies, mainly the" classical "type of spiral, an empirical relationship was established between the total gravitational acceleration of the stars (observed) and the component we would observe in classical Newton in the presence of just ordinary matter Empirical relationship, which seemed valid in all the galaxies analyzed and in each galactic radius, motivated the explanation of gravitational acceleration, without necessarily questioning dark matter, but, for example, theories of modified gravitation, such as modified Newtonian dynamics (MOND). "

Di Paolo and her co-workers wanted to examine this relationship and analyze the rotation curves of galaxies other than the classic spiral type – 72 low-surface-brightness (LSB) galaxies and 34 dwarf-disk galaxies. They yielded expanded results and found a relationship that included the galactic radius and the morphology of the galaxies in addition to the overall acceleration and its ordinary component.

"We have studied the relationship between total acceleration and its ordinary component in 106 galaxies whose results differ from those previously observed," explains Paolo Salucci, Professor of Astrophysics at SISSA and one of the research authors. "This not only demonstrates the inaccuracy of the previously described empirical relationship, but also eliminates doubts about the existence of dark matter in galaxies, and the new relationship could provide crucial information for understanding the nature of this indeterminate component."


A galactic test to clarify the existence of dark matter


Further information:
C. Di Paolo et al. Radial Acceleration Relation (RAR): Important Cases of Dwarf Slices and Low-Brightness Galaxies (19459010), The Astrophysical Journal (2019). DOI: 10.3847 / 1538-4357 / aaffd6

Provided by
International School for Advanced Studies (SISSA)




Quote :
Dark Matter Exists: Observations refute alternative explanations (2019, April 30)
retrieved on April 30, 2019
from https://phys.org/news/2019-04-dark-alternate-explanations.html

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