Home / Science / “Big Bang of Galactic Size”: Largest Black Holes in the Observable Universe May Be a Source of Dark Matter (weekend feature)

“Big Bang of Galactic Size”: Largest Black Holes in the Observable Universe May Be a Source of Dark Matter (weekend feature)



Albert Einstein described black holes as “the most perfect macroscopic objects in the universe: the only elements in their construction are our concepts of space and time”, which has inspired astrophysicists to wonder how big these objects are. paradoxical, could these “Gates of Hell” become?

A team of scientists now suggests that these behemoths lurking in the center of galaxies could reach “stupendously large” sizes, where the greater their mass, the greater their power, “they would be like a mini Big Bang the size of a galaxy,” second to Julie Hlavacek-Larrondo, at the Université de Montréal, who holds the Canadian Research Chair in Observational Black Hole Astrophysics. These enigmatic objects, as stated by quantum theory, could be incredibly complex and concentrate an enormous amount of information within them, the largest hard drive in nature, in two dimensions.

“Beautifully large black holes” (SLAB)

The discovery of such gigantic black holes could shed light on the nature of a significant fraction of the mysterious dark matter. These “stupendously large black holes” (SLABs) in galactic nuclei exist in theory and may have been seeded by primordial black holes, suggests Florian Kuhnel who holds the chair of cosmology at the Arnold Sommerfeld Center for Theoretical Physics. The largest known black hole in the observable universe is fueling the quasar TON 618 with a mass of 66 billion solar masses, leading to conjectures that even larger ones exist inside or outside the observable universe, and question whether it exists an upper limit to their size.

Primordial black holes: source of dark matter?

Which leads to speculation that primordial black holes formed during the cosmic dark age after the Big Bang, before the formation of the first stars. “It has been speculated that there may be black holes that formed in the early universe before stars existed, “said Savvas Koushiappas, a dark matter physicist at Brown University, of the possibility that with future gravitational wave experiments, we will be able to look back to a time before the first stars formed to see if the events of black holes existed before stars formed in the cosmos, then we will know that those black holes are not of stellar origin.

“Big Bang Fireflies”: Did Primordial Black Holes Create Dark Matter?

Gravity wells at the Big Bang

These primordial black holes, gravitational wells formed moments after the Big Bang, could be an explanation for dark matter. Shortly after the Big Bang, fluctuations in quantum mechanics led to the density distribution of matter that we observe today in the expanding universe. Some of these density fluctuations may have been large enough to cause black holes scattered across the universe, suggested Koushiappas, co-author of the 2017 study with Harvard’s Avi Loeb. The study outlined how scientists could use gravitational wave experiments to test the existence of primordial black holes first proposed in the early 1970s by Stephen Hawking and collaborators but which have yet to be detected.

“Before the First Stars” – Primordial black holes, gravity wells formed moments after the Big Bang

“Either primordial black holes exist or the early universe evolved in a very different way from the standard cosmological model. Both would be very important discoveries, say Koushiappas and Loeb. Primordial black holes, Loeb and Koushiappas suggest, fall into one category. of entities known as MACHO or Massive Compact Halo Objects. Some scientists have proposed that dark matter – the invisible matter thought to comprise most of the mass of the universe – may be composed of MACHOs in the form of primordial black holes. of primordial black holes would reinforce this idea, while continued non-detection would cast doubt on it.

“The really exciting thing about primordial black holes is that there are so many mysteries that they could in principle explain,” says Stephen Hawking’s colleague, physicist Bernard Carr. “Not least the existence of dark matter and dark energy.”

“An interesting possibility is that a population of primordial black holes may have created dark matter in the early universe,” wrote Dan Hooper, head of the theoretical astrophysics group at Fermilab in response to an email from the Daily Galaxy, asking Hooper what new physics might be revealed by the discovery of these elusive relics. “If these black holes were initially lighter than a million kilograms or so,” Hooper added, “they would have evaporated in the first second after the Big Bang. In the process of this evaporation, they could have created any number of shapes. exotic matter and energy, including dark matter “.

The Daily Galaxy, Max Goldberg, via Arxiv.org, New Scientist, Bernard Carr, Primordial Black Holes as Dark Matter, Black Holes Existed Before Stars, and Primal Black Holes as Dark Matter

Image credit: Shuttertstock license




Source link