Key points
- Primordial black holes may explode soon
- Hawking’s radiation theory may be proven
- Discovery could rewrite Universe’s particle history
ISLAMABAD: There is a strong possibility that, within the next decade, astronomers could witness a rare cosmic event: a deep space explosion that not only proves long-held theories about black holes but also reveals every fundamental particle in existence — both known and unknown.
At least that is what new studies by physicists at the University of Massachusetts Amherst (UMass Amherst) suggest, who think that these explosions are the death of ancient, miniature black holes formed in the early days of the Big Bang.
These events are believed to be much more common than previously believed (once every 100,000 years). According to the new analysis of the team, one such explosion may occur once in every ten years, and we already have the technology to detect it.
Breakthrough discovery
If spotted, it would mark a watershed moment in astrophysics. Not only would it confirm the existence of a long-theorised class of black holes, known as primordial black holes (PBHs), but it would also identify how black holes ultimately die.
More remarkable is what is likely to emerge from such a burst of all types of fundamental particles, both known and unknown, such as electrons and neutrons, and particles we are certain exist, such as those that constitute dark matter.
But the most exciting outcome? The particles we’ve never even imagined.
Rewriting history of Universe
“We would also get a definitive record of every particle that makes up everything in the Universe,” says Joaquim Iguaz Juan, an astrophysicist at UMass Amherst. “It would completely revolutionise physics and help us rewrite the history of the Universe.”
The idea of an explosion of this type dates back to a 1974 prediction by Stephen Hawking that black holes, despite their reputation as vacuum cleaners in the universe, emit particles gradually in a phenomenon now called Hawking radiation. This would eventually lead to the gradual loss of mass, and the black hole would evaporate completely, resulting in a supernova-like explosion.
Supermassive black holes
Whereas stellar-mass and supermassive black holes would require billions of years to reach such a stage, PBHs, small black holes with masses similar to asteroids, may already be in their last moments.
“The lighter a black hole is, the hotter it should be and the more particles it will emit. As PBHs evaporate, they become ever lighter, and so hotter, emitting even more radiation in a runaway process until explosion,” explains Andrea Thamm, physicist at UMass Amherst.
Most PBHs would have evaporated by this time under the Standard Model. However, the scientists made minor changes to the theory, such as a hypothetical darker form of the electron, the so-called dark electron, which can radically change the chronology.
Delayed explosive death
Such variations indicate that there is the possibility that some PBHs possess some sort of electric charge that slows down Hawking radiation and delays their explosive death.
“We show that if a primordial black hole is formed with a small dark electric charge, then the toy model predicts that it should be temporarily stabilised before finally exploding,” says Michael Baker, also a physicist at UMass Amherst.
Provided that the calculations of the team are right, an explosion like this one can be detected by the available gamma-ray telescopes about every ten years.
The fact that a single one would not only verify the existence of primordial black holes and be the first direct observation of Hawking radiation, but would also give a previously unseen full picture of the particle composition of the Universe.
