By Nikola 
It’s possible that tiny black holes made a
major difference in the early universe. It is proposed in a new publication by
physicists that a vast number of microscopic black holes could have filled the
young universe with particles and radiation, triggering their own black
hole-powered Big Bang.
There is currently just one known method
for creating black holes. You need to start with a really large star, and then
you need to kill it. As its life cycle winds down, its center begins to give
way. It continues to collapse towards a singularity because there is no other
force strong enough to prevent it from doing so. This is how astronomers think
all black holes began, from the stellar-mass ones found in every galaxy to the
supermassive ones found at the centers of galaxies. However, there might be an alternative. After inflation, the proposed event that set off a great expansion event that
blew our cosmos to tremendous sizes in less than a second made the early
universe even more chaotic and energized.
When inflation stopped, the pent-up forces
were released, causing space and time to tremble and vibrate. There’s a chance
that things became so bad in the cosmos that isolated regions of space-time
achieved critical density and size on their own accord, unleashing a deluge of
“primordial” black holes. Stephen Hawking first postulated the
existence of these primordial black holes, and astronomers have spent decades
either searching for them or ruling them out. Black holes larger than around a
billion grams (roughly the mass of a typical mountain on Earth) have been ruled
out by several observations as candidates for the existence of extraterrestrial
life.
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| Artist’s impression of the supermassive black hole in the M87 galaxy and its powerful jet. (Image credit: S. Dagnello (NRAO/AUI/NSF)) |
Arrested development
However, not many scientists have
considered the possibility that smaller black holes, the size of mountains,
emerged as a result of inflation. This prompted a group of physicists to
investigate the possible behavior of these more compact black holes, as well as
possible methods for detecting them. In a manuscript published to the online
preprint databasearXiv(opens in new tab), they described their findings in
full.
There is an end to every black hole’s
existence. Hawking revealed that black holes actually have a bluish tint.
Instead, radiation is progressively emitted from their event horizons via an
unusual quantum mechanism. To put it simply, the procedure is exceedingly slow.
Black holes of stellar masses typically emit no more than a single radiation
particle each year. However, black holes with a lesser mass emit radiation at a
higher pace. These smaller primordial black holes wouldn’t have survived more
than a few minutes due to Hawking radiation’s evaporative effects. This happened a long time before the next
major era in the history of the universe, which was the time when the first components
were created. Therefore, these black holes would have been free to leave the
scene before the current observational limits were established.
However, as the report explains, there are
still methods that can be used to identify such tiny black holes from the
beginning of time. The most significant effect may have been
that these black holes slowed down the expansion of the cosmos. We live in an
ever-expanding universe. In other words, as the universe expanded through
inflation, the density of matter and radiation rapidly decreased.
However, the evolution we see today might
not have happened if the primordial black holes weren’t around. They would have
started producing Hawking radiation, converting their mass into radiation,
almost immediately after they were created. According to the researchers, the
density may have remained constant in the immediate aftermath of the Big Bang
because tiny black holes added radiation at the same rate as the cosmos diluted
it.
Primordial instincts
As the black holes did their thing, the
universe would have entered a kind of “stasis,” halting its normal
expansion-driven evolution. The team found that this scenario would have
allowed the black holes to exert a wide range of consequences on the cosmos
without contradicting any established facts. They emerge, do their thing while
the cosmos pauses for them, and then vanish, with the rest of cosmic history
proceeding as usual. For instance, it is possible that the
presence of dark matter and dark energy in the cosmos can be attributed to the
evaporation of these primordial black holes. They could have also sparked
baryogenesis, which would have resulted in more matter than antimatter in the
universe.
Additionally, primordial black holes may
have inundated the universe with their own distinct signal of gravitational
waves. Neither existing ground-based detectors nor those planned for launch
within the next decade (such as the Laser Interferometer Space Antenna) have
the sensitivity necessary to detect these gravitational waves.