Science.- Are black holes and dark matter the same?

MADRID, 21 (EUROPA PRESS)

By proposing an alternative model for how the universe came to be, a team of astrophysicists suggests that all black holes were created just after the Big Bang and represent all dark matter.

That’s the implication of a study by astrophysicists at the University of Miami, Yale and ESA suggesting that black holes have been around since the beginning of the universe and that these primordial black holes could constitute the still inexplicable dark matter.

If proven to be true with data collected by the James Webb Space Telescope, the discovery may transform scientific understanding of the origins and nature of two cosmic mysteries: dark matter and black holes.

“Our study predicts what the early universe would look like if, instead of unknown particles, dark matter were made up of black holes formed during the Big Bang, as suggested by Stephen Hawking in the 1970s,” Nico Cappelluti said in a statement, assistant professor of physics at the University of Miami and first author of the study published in The Astrophysical Journal.

“This would have several important implications. First, we would not need ‘new physics’ to explain dark matter. Furthermore, this would help us answer one of the most compelling questions in modern astrophysics: How could supermassive black holes in the early universe have grown so fast? Given the mechanisms we observe today in the modern universe, they would not have had enough time to form. This would also solve the ancient mystery of why the mass of a galaxy is always proportional to the mass of the supermassive black hole in its center “, he exposes.

Dark matter, which has never been directly observed, is believed to be most of the matter in the universe and acts as the scaffolding on which galaxies form and develop. On the other hand, black holes have been observed, which can be found at the centers of most galaxies. A point in space where matter is so tightly packed that it creates intense gravity.

Co-authored by Priyamvada Natarajan, professor of astronomy and physics at Yale, and Günther Hasinger, director of science at the European Space Agency (ESA), the new study suggests that so-called primordial black holes of all sizes represent all dark matter in the universe.

“Black holes of different sizes remain a mystery,” Hasinger explained. “We don’t understand how supermassive black holes could have grown so large in the relatively short time available since the universe existed.”

His model modifies the theory first proposed by Hawking and his fellow physicist Bernard Carr, who argued that in the first fraction of a second after the Big Bang, small fluctuations in the density of the universe may have created an undulating landscape with “bulging” regions. it had extra dough. These bulging areas would collapse into black holes.

That theory did not gain scientific force, but Cappelluti, Natarajan, and Hasinger suggest that it could be valid with a few minor modifications. His model shows that the first stars and galaxies would have formed around black holes in the early universe. They also propose that primordial black holes would have had the ability to become supermassive black holes by feasting on gas and stars in their vicinity, or by merging with other black holes.

“Primordial black holes, if they exist, could well be the seeds from which all supermassive black holes are formed, including the one at the center of the Milky Way,” Natarajan said. “What I personally find very exciting about this idea is how it elegantly unifies the two really challenging problems I work on, that of probing the nature of dark matter and the formation and growth of black holes, and solves them in one go. time”.

Primordial black holes can also solve another cosmological puzzle: excess infrared radiation, synchronized with X-ray radiation, which has been detected from faint, distant sources scattered throughout the universe. The study authors said that growing primordial black holes would exhibit “exactly” the same radiation signature.