In a new paper in the journal Physical overview letters, an international team of theoretical physicists described a scenario for the formation of primordial black holes from vacuum bubbles in the early Universe and discussed its intriguing realization which, of course, could account for all dark matter.
‘Baby universes’ that branch off from our universe shortly after the big bang seem to us like black holes. Image Credit: Kavli Institute for Physics and Mathematics of the Universe.
Primordial black holes are hypothetical compact objects that formed in the early universe before any galaxies and stars.
They are a viable candidate for dark matter; the missing matter that, according to astrophysicists, makes up 85% of the universe.
These compact objects, first introduced a few decades ago, may play a central role in a variety of astrophysical phenomena, such as progenitors for gravitational waves and seeds for the formation of supermassive black holes.
They can also play a role in the synthesis of heavy elements when they collide with and destroy neutron stars, thus releasing neutron-rich material.
In the new paper, dr. Alexander Kusenko of the Kavli Institute for the Physics and Mathematics of the Universe and the University of California, Los Angeles and his colleagues from Japan, the United States and Taiwan described a ‘multiverse’ scenario of the original black hole. formation.
“The early universe was so dense that any positive density fluctuation of more than 50% would create a black hole,” they explained.
‘However, cosmological disturbances that cause galaxies to sow are known to be much smaller. Nevertheless, a number of processes in the early universe could have created the right conditions for the formation of black holes. ‘
‘One exciting possibility is that primordial black holes could emerge from the’ baby universe ‘that emerged during inflation, a period of rapid expansion that is believed to be responsible for sowing the structures we observe today, such as galaxies and clusters of galaxies. “
‘During inflation, baby universes can branch out from our universe. A small baby (or ‘daughter’) universe would eventually collapse, but the large amount of energy released in the small volume causes a black hole to form. ”
An even more bizarre fate awaits a larger baby universe. If it is larger than a critical size, Einstein’s theory of gravity allows the baby universe to be in a state that looks different from an observer on the inside and the outside. ”
“An internal observer sees it as an expanding universe, while an external observer sees it as a black hole.”
“In both cases, the large and the small baby universe are seen by us as primordial black holes, hiding the underlying structure of multiple universes behind their horizons.”
Dr. Kusenko and co-authors also showed that the original black holes could be detected using the Hyper Suprime-Cam (HSC) of the 8.2 m Subaru telescope.
“We demonstrate with numerical studies that future observations of HSC, as well as other optical recordings, such as the Vera C. Rubin Observatory, will be able to provide a definitive test for this generic primordial mechanism for black holes if it is the dominant source. of dark matter, ”they said.
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Alexander Kusenko et al. 2020. Explore primordial black holes from the multiverse with optical telescopes. Fis. Ds Lett 125 (18): 181304; doi: 10.1103 / PhysRevLett.125.181304