Hawking radiation may have shaped early universe, study finds
New research suggests that the theoretical Hawking radiation generated by black holes may have influenced the early structure of the universe.
As reported by Live Science, Stephen Hawking introduced a groundbreaking concept in the 1970s that black holes could emit radiation similar to the heat given off by heated objects. This phenomenon, known as Hawking radiation, remains theoretical due to the minimal emission power calculated for both ordinary and supermassive black holes.
The latest research, published in the "Journal of Cosmology and Astroparticle Physics," suggests that this elusive radiation may have significantly impacted the early structure of the universe. Scientists propose that primordial black holes, possibly existing shortly after the Big Bang, could have emitted intense Hawking radiation, leaving detectable traces in the universe we observe today.
"An intriguing possibility is that the early universe underwent a phase in which its energy density was dominated by primordial black holes, which then evaporated through Hawking radiation," the scientists noted in their study.
Primordial black holes and their significance
Hawking partially merged the mathematical frameworks of general relativity and quantum mechanics to explore the physics of black holes. He discovered that black holes could emit particles, including photons (light). Notably, the emission rate decreases as the black hole's mass increases, meaning black holes formed from collapsing stars and supermassive black holes emit radiation that is too weak to be detected by current instruments.
However, the early universe might have contained much smaller black holes, each with a mass of less than 110 tons. These so-called primordial black holes could have emitted particles at a rate sufficient to influence cosmic structures such as galaxies and clusters.
Searching for Hawking relics
Scientists have studied how Hawking relics might impact the current cosmic arrangement. Although they have not found direct evidence of these relics' existence, their analysis has allowed them to constrain the properties of both the particles and the primordial black holes that might have emitted them.
Physicists explained that if a large number of black holes had evaporated during the formation of the first atomic nuclei, it would have disrupted the expected abundance of those nuclei in the universe. To avoid this inconsistency, they concluded that primordial black holes must have evaporated earlier, setting an upper mass limit of 500 metric tonnes.
Although current observations have not confirmed the existence of Hawking relics, scientists remain optimistic. They believe that future instruments with increased precision may detect these relics, confirming the existence of Hawking radiation and primordial black holes, and enabling experimental studies of their properties.
The discovery of a Hawking relic would open up new research opportunities in particle physics beyond the Standard Model and provide the first observational evidence of Hawking radiation, black hole evaporation, and primordial black holes. This could significantly expand our knowledge of the early universe.
