The early universe contained far fewer miniatures black holes A new study has suggested that the origin of our universe’s missing matter is even more of a mystery than previously thought.
Miniature or primordial black holes (PBHs) are black holes thought to have formed in the first fractions of a second after the Big Bang. According to leading theories, these dime-sized singularities arose from rapidly collapsing regions of dense, hot gas.
Pockets of infinitely dense spacetime are how many physicists explain the universe’s dark matter, a mysterious entity that, despite being completely invisible, makes the universe much heavier than can be explained by the matter we can see.
But while the hypothesis is popular, it has one major problem: we have yet to directly observe any primordial black holes. Now, a new study has offered a possible explanation for why they didn’t form, throwing open cosmology’s dark matter problem to wider speculation.
According to the research, the modern universe could have taken shape with far fewer primordial black holes than previous models estimated. The researchers published their findings on May 29 in the journal Physical inspection letters.
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“Many researchers feel this [primordial black holes] are a strong candidate for dark matter, but there would have to be a lot of them to satisfy this theory,” said the lead author Jason Christianograduate student in theoretical physics at the University of Tokyo, he said in a statement. “They are interesting for other reasons as well, since the recent innovation of gravitational wave astronomy has seen the discovery of binary black hole mergers, which can be explained by the fact that PBHs exist in large numbers. But despite these strong reasons for their expected number, we have not seen any directly and now we have a model that should explain why this is the case.”
A hole in the picture
The universe began 13.8 billion years ago with Big Bangcausing the young universe to explode outwards due to an invisible force known as dark energy.
As the universe grew, ordinary matter that interacts with light solidified around clumps of invisible dark matter to create the first galaxies, linked together by a vast cosmic web. Today, cosmologists think that ordinary matter, dark matter, and dark energy make up about 5%, 25%, and 70% of the composition of the universe, respectively.
In the beginning, the universe was an opaque, plasma broth through which no light could pass without being captured by electromagnetic fields created by moving charges. Still, after 380,000 years of cooling and expansion, the plasma eventually recombined into neutral matter, emitting microwave static electricity that became the first light of the universe, the cosmic microwave background (CMB).
Cosmologists searched for these early black holes by studying this first baby picture of the universe. However, none have been found yet.
Some physicists believe that there is a possibility that they have not discovered the huge number of primordial black holes necessary to explain dark matter simply because they have yet to learn how to detect them.
But by applying a model built on an advanced form of quantum mechanics called quantum field theory to the problem, the scientists behind the new study came to a different conclusion — we can’t find any primordial black holes because most simply aren’t there. PUSH.
Primordial black holes are thought to have formed from the collapse of short but powerful gravitational waves rippling through space. By applying their model to these waves, the researchers found that it may take far fewer of these waves to connect larger structures in the universe than other theories estimate. And the fewer waves needed to restore the image, the fewer primordial black holes.
“It is widely believed that the collapse of short but powerful wavelengths in the early universe creates the primordial black holes,” Kristiano said. “Our study suggests that there should be far fewer PBHs than needed if they are indeed a strong candidate for dark matter or gravitational wave events.”
To confirm their theory, the scientists will look at future hypersensitive gravitational wave detectors, such as The Laser Interferometer Space Antenna (LISA) project.which is to be sent into space on the Ariane 3 rocket in 2035.