Physicists believe that when tiny primordial black holes interact with dark matter, the latter can produce flashes of light in the form of gamma radiation. These light bursts could allow for a direct observation of the mysterious dark matter and provide insights into its nature. This research is available on the preprint server arXiv, as reported by Live Science.
The majority of the mass of nearly all galaxies in the universe is composed of dark matter, yet physicists do not fully understand its composition. It is known that dark matter possesses gravity but does not interact with light and does not emit its own light. Scientists are aware of the existence of this invisible form of matter solely through the gravitational influence of dark matter on ordinary matter, which makes up all visible objects in space.
Consequently, researchers are exploring various methods to directly detect dark matter, which has yet to be observed. The authors of the new study propose a theory suggesting that invisible matter can be detected using black holes. This may sound illogical, as it raises the question of how objects that absorb any light could be utilized for this purpose. How can black holes make dark matter glow?
Physicists think that dark matter may indeed interact with ordinary matter and produce light, but for some reason, this does not occur. It is possible that a certain amount of energy, which is not available in this context, is required, or that this energy cannot exist without a mediator for such an interaction. Researchers believe that unconventional black holes could serve as this mediator, enabling dark matter to emit light.
According to the study's authors, these objects could be tiny primordial black holes. Their size may be no larger than that of an atom, yet they possess the mass of an asteroid. Primordial black holes did not form from the collapse of massive star cores but are a product of the chaotic conditions during the universe's earliest history. It is believed that spontaneous compression of clumps of ordinary matter could have created such black holes.
To date, scientists have not discovered primordial black holes, and it is thought that if they still exist, they are extremely rare. Like all black holes, primordial black holes gradually evaporate through Hawking radiation. The smaller the black hole, the more radiation it emits, and the faster it disappears. It is suggested that these rare primordial black holes emit a significant amount of radiation in the current universe.
However, this radiation is not merely a collection of light particles or photons. Physicists believe that primordial black holes emit almost all known types of particles as radiation, including dark matter particles. These particles then energize any surrounding dark matter particles near the primordial black holes, triggering a cascade that results in temporary light that can be observed.
According to the study, these fleeting light bursts would constitute gamma radiation. However, this radiation is too faint for current gamma observatories to detect. Yet, future observatories may possess the necessary sensitivity to identify this radiation, physicists believe.