The universe may be full of small ancient black holes. And researchers may be able to prove it.
From the beginning, these mini black holes, or primordial black holes (PBHs), were first dreamed of decades ago.Researchers suggested them as explanations Dark matter, An invisible substance that exerts an attractive force on the entire universe. Most descriptions of dark matter include fictitious particles with special properties that help avoid detection. However, some researchers believe that a group of small black holes that move like clouds in the universe provide a clearer explanation. Now, a new study explains where these PBHs came from and how astronomers can detect the aftershocks of their birth.
Where did the little black hole come from?
A black hole is a singularity, an infinitely dense point in a space filled with matter. It’s that problem is very dense, gravity Overwhelming everything else, the problem collapses.Distort Space-time It then surrounds itself with the “event horizon,” which is a spherical boundary area where light cannot escape beyond that.
General law Theory of relativity Allow black holes to exist on any scale. If you crush the ants hard enough, they will collapse into black holes like stars. It will be incredibly small.
Most PBH theories assume that these objects have a small planet-like mass and the event horizon is as small as a grapefruit. Joey Neilsen, a physicist at Villanova University who was not involved in the new study, said it was a quirky idea still around black holes and dark matter physics. But recently, as other dark matter theories have been emptied, some researchers have revisited the concept of PBH.
However, if PBH is present, it must be very old. In the modern universe, there are only two known ways to create new black holes from ordinary matter. A star that is much heavier than the Sun collides or explodes.Therefore, all known black holes will be heavier than the whole Solar system (Sometimes much).
Relation: Is the mysterious “Planet 9” of our solar system really a grapefruit-sized black hole?
Creating a small black hole requires all other mechanisms and elements.
Those ingredients will be “the ones of the Big Bang, the same as making stars and galaxies,” Nielsen told Live Science.
Immediately after big BangThe newly expanding universe was full of hot, dense, almost undifferentiated matter that expanded in all directions. There were small turbulent pockets in this swamp — still visible as fluctuations in the cosmic microwave background (CMB), the afterglow of the Big Bang — and those fluctuations gave the cosmic structure.
“If it’s point A and a little more dense, then things are gravitationally attracted to point A,” Nielsen said. “And throughout the history of the universe, its gravitational pull causes gas and dust to fall inward, coalesce, collapse, and form stars, galaxies, and all the structures of the universe we know.”
Most PBH theories involve very violent fluctuations in the early universe, stronger than those that formed the galaxy.
In this new treatise, researchers place those volatile fluctuations during a period known as “inflation.” In the first hundred billionth of a second after the Big Bang, the universe expanded exponentially rapidly.Researchers believe that its rapid early expansion gave space-time the current “flat” shape, which probably prevented the space from curving. Live Science previously reported..
In a new treatise published on November 20th arXiv Databases, researchers suggest that during inflation, there may have been moments when all of space-time was sharply curved before it finally flattened. However, these short curvatures were strong enough to cause fluctuations in the expanding universe and eventually form a large population of Earth-mass black holes.
How to find a small black hole
Researchers write that the easiest way to prove that this theory is correct is to look for “secondary gravitational waves” (SGWs) that echo around the universe.
These waves are much weaker than the gravitational waves produced by the collision of black holes and reverberate from the same perturbations that formed the PBH. They are subtle vibrations of the universe that are inaudible to current detectors. But you may be able to find them in two future ways.
One approach: Pulsar timing array. The universe is full of swirling neutron stars known as pulsars that send a flash of energy toward Earth as they rotate. A pulsar is like an accurate and predictable clock in the sky, but its signal can be distorted by gravitational waves. Secondary gravitational waves passing between the Earth and the pulsar distort space-time, causing the pulsar scale to arrive a little earlier or later in a way that the pulsar timing array can detect.
However, there is a problem with this plan. The pulsar timing array relies on accurately detecting the ticks of the emitted pulsar. Radio waves.. And the giant Arecibo telescope in Puerto Rico, one of the world’s most important radio detectors, was essentially destroyed. As reported by LiveScience’s sister site Space.com..
However, the authors write that even if high-quality pulsar timing experiments do not work for the next 15 years, next-generation gravitational wave detectors should be sensitive enough to pick up these secondary gravitational waves. I will.
Currently, gravitational wave detectors are buried underground, looking for space-time fluctuations by measuring changes in light travel time over long distances. But other effects—small earthquakes, waves crashing into distant shores, and even rabbits flying overhead—can muddy the signal. In 2034, the European Space Agency plans to launch the Laser Interferometer Space Antenna (LISA), a much more sensitive space-based gravitational wave detector that avoids these pitfalls. And the LISA written by the author should be able to pick up secondary gravitational waves.
They wrote that such detection proves that PBH occupies most (if not all) of the dark matter in the universe.
Originally published in Live Science.
A flock of “primordial black holes” may fill our universe
Source link A flock of “primordial black holes” may fill our universe