The Sun emits an unceasing stream of neutrinos called solar neutrinos, but they’re not very energetic. KM3-230213A, the name given to the 100 PeV neutrino, dwarfs the Sun’s neutrino output. That event was one billion times more energetic than your average solar neutrino. <\/p>\n
There’s not a long list of astrophysical phenomena that could potentially juice a neutrino like this. In fact, no currently well-understood object or process can account for it. <\/p>\n
When Nature sends us a message like this, something important is encoded in it. It’s up to physicists to determine what it means. And in the intervening couple of years since its detection, different physicists have generated different explanations for it. <\/p>\n
Explanations include pulsar-powered optical transients<\/a>, gamma-ray bursts<\/a>, dark matter decay<\/a>, active galactic nuclei, black hole mergers<\/a>, and several explanations based on different types of primordial black holes. <\/p>\n New research in Physical Review Letters has another explanation, and this one is based on primordial black holes, too. The research is titled “Explaining the PeV neutrino fluxes at KM3NeT and IceCube with quasiextremal primordial black holes<\/a>,” and the lead author is Michael Baker. Baker is an assistant professor of physics at the University of Massachusetts, Amherst.<\/p>\n “The KM3NeT experiment has recently observed a neutrino with an energy around 100 PeV, and IceCube<\/a> has detected five neutrinos with energies above 1 PeV,” the authors write. “While there are no known astrophysical sources, exploding primordial black holes could have produced these high-energy neutrinos.” <\/p>\n Primordial black holes<\/a> are entirely hypothetical. Theory says that unlike stellar-mass black holes, PBH didn’t need a massive star to explode and collapse in order to form. Instead, they formed immediately after the Big Bang from dense clumps of sub-atomic matter, when the physics underlying the Universe were much different. <\/p>\n PBH are much smaller than stellar mass black holes, but they’re still incrediby dense and the old adage that “nothing, not even light, can escape a black hole” still applies to them. But PBH share something else with their cousins: Hawking Radiation<\/a>. <\/p>\n Stephen Hawking developed the idea for Hawking Radiation (HR). Basically, it says that over time HR reduces a black hole’s mass, and that eventually a black hole will evaporate, unless it accretes more matter. Unfortunately, HR is normally so weak that it’s well below the detection threshold of even our most capable telescopes. <\/p>\n This HR-inspired evaporation could be behind KM3-230213A. While it’s undetectable around stellar mass black holes, the situation may be different when it comes to much lighter PBH. <\/p>\n “The lighter a black hole is, the hotter it should be and the more particles it will emit,” said co-author Andrea Thamm, an assistant professor of physics at UMass Amherst, in a press release<\/a>. “As PBHs evaporate, they become ever lighter, and so hotter, emitting even more radiation in a runaway process until explosion. It\u2019s that Hawking radiation that our telescopes can detect.”<\/p>\n As a PBH evaporates via runaway HR, they eventually experience a final burst. In their final second, they become extremely hot and suffer an explosive evaporation. This final act can produce high-energy neutrinos like KM3-230213A. <\/p>\n The researchers think that this could happen every decade, approximately, and that the explosions can produce a cornucopia of sub-atomic particles. They think that these PBH evaporative explosions could produce a catalogue of all of the sub-atomic particles that exist. Not just the ones we know about, like electrons and quarks, but also ones that are only hypothesized at this time, and others that that may be completely unknown. <\/p>\n The research team thinks that KM3-230213A could be the evidence for PBH evaporation. But there’s one problem. <\/p>\n The IceCube Neutrino Observatory didn’t detect the event, and in fact has never detected any neutrino close to being as energetic as KM3-230213A. If a PBH evaporation explosion happens every decade, shouldn’t IceCube have detected at least one? IceCube has been observing for 20 years. <\/p>\n![\"There's](\"https:\/\/www.newsbeep.com\/us\/wp-content\/uploads\/2026\/02\/010125_black-holes_feat_20260205_201823.jpg\"\/)
<\/a> *There’s a lot of questions about primordial black holes. It’s possible that they could’ve helped the very first stars form, if they exist. Image Credit: NASA and G. Bacon\/STSCI*<\/p>\n
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<\/a> *This is the IceCube Neutrino Observatory in Antarctica. The neutrino detectors are attached to an array of strings that are sunk into the ice. Image Credit: By Christopher Michel – Own work, CC BY-SA 4.0, https:\/\/commons.wikimedia.org\/w\/index.php?curid=128003225*<\/p>\n