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3 days ago
- Science
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Scientists use Stephen Hawking theory to propose 'black hole morsels' — strange, compact objects that could reveal new physics
When you buy through links on our articles, Future and its syndication partners may earn a commission. Tiny black holes created in the aftermath of violent cosmic collisions could offer unprecedented insight into the quantum structure of space and time, a new theoretical study proposes. What's more, signals from these "black hole morsels" could potentially be detected by current instruments, scientists reported in the study, which was published in the journal Nuclear Physics B. "Our work shows that if these objects are formed, their radiation might already be detectable using existing gamma-ray observatories," Francesco Sannino, a theoretical physicist at the University of Southern Denmark and co-author of the study, told Live Science via email. Hawking radiation and the smallest black holes One of the deepest mysteries in modern physics is how gravity behaves at the quantum level. The new study offers a bold proposal to explore this regime by looking for the glow produced by tiny black holes created in the aftermath of giant black hole collisions. The idea that black holes are not entirely black, and therefore could emit faint radiation, was first proposed by Stephen Hawking in the 1970s. His calculations revealed that quantum effects near a black hole's event horizon would cause it to emit radiation and lose mass — a process now known as Hawking radiation. The black hole temperature is predicted to be inversely proportional to its mass. So for massive astrophysical black holes, the effect is minuscule, with temperatures so low that the radiation is effectively undetectable. But for very small black holes, the situation is different. "Black hole morsels are hypothetical micro-black holes that could be formed during the violent merger of two astrophysical black holes," Giacomo Cacciapaglia, a senior researcher at the French National Centre for Scientific Research (CNRS) and co-author of the study, said in an email. "Unlike the larger parent black hole, these morsels are much smaller — comparable in mass to asteroids — and thus much hotter due to the inverse relationship between black hole mass and Hawking temperature." Related: Scientists detect most massive black hole merger ever — and it birthed a monster 225 times as massive as the sun Because of this elevated temperature, these morsels would evaporate relatively quickly, releasing bursts of high-energy particles such as gamma-rays and neutrinos. The team's analysis suggests that this radiation could form a distinct signal that may already be within reach of present-day detectors. A new handle on quantum gravity Although no such morsels have been observed yet, the researchers argue that the formation of these tiny black holes is theoretically plausible. "The idea is inspired by analogous processes in neutron star mergers," Stefan Hohenegger, senior researcher at the Institut de Physique des Deux Infinis de Lyon and co-author of the study, explained in an email. "It's supported by estimates from beyond-General Relativity frameworks, including string theory and extra-dimensional models." In such extreme environments, small-scale instabilities might pinch off tiny black holes during the merger process. These objects, in turn, could evaporate through Hawking radiation over timescales ranging from milliseconds to years, depending on their mass. Crucially, if such radiation is detected, it could open a window into new physics. "Hawking radiation encodes information about the underlying quantum structure of spacetime," Sannino said. "Its spectral properties could reveal deviations from the Standard Model at extreme energy scale, potentially leading to discoveries of unknown particles or such phenomena as extra dimensions predicted by various theories." Such energy scales lie far beyond the reach of even the most powerful particle colliders, like the Large Hadron Collider at CERN. The possibility that black hole morsels might provide a natural "accelerator" for probing these physics is what makes them so compelling. According to the team, the signature of a black hole morsel would be a delayed burst of high-energy gamma-rays radiating in all directions — unlike typical gamma-ray bursts, which are usually beamed. Instruments capable of detecting such high-energy signals include atmospheric Cherenkov telescopes, like the High Energy Stereoscopic System (HESS), in Namibia; the High-Altitude Water Cherenkov Observatory (HAWC), in Mexico; and the Large High Altitude Air Shower Observatory (LHAASO) in China, as well as satellite-based detectors, like the Fermi Gamma-ray Space Telescope. "Some of these instruments already have the sensitivity required," Hohenegger noted. The researchers didn't stop at theorizing. They used existing data from HESS and HAWC to place upper bounds on how much mass could be emitted in the form of morsels during known black hole mergers. These limits represent the first observational constraints on such phenomena. "We showed that if black hole morsels form during mergers, they would produce a burst of high-energy gamma rays, with the timing of the burst linked to their masses," Cacciapaglia said. "Our analysis demonstrates that this novel multimessenger signature can offer experimental access to quantum gravitational phenomena.' What comes next While the study provides a compelling case for morsels, many uncertainties remain. The exact conditions for their formation are still poorly understood, and no full simulations have been performed at the scales necessary to model them. But the researchers are optimistic. RELATED STORIES —See the universe's rarest type of black hole slurp up a star in stunning animation —Exotic 'blazar' is part of most extreme double black hole system ever found, crooked jet suggests —Paperclip-sized spacecraft could visit a nearby black hole in the next century, study claims "Future work will involve refining the theoretical models for morsel formation and extending the analysis to include more realistic mass and spin distributions," Sannino said. The team also hopes to collaborate with observational astronomers to perform dedicated searches in both archived and upcoming datasets. "We hope this line of research will open a new window into understanding the quantum nature of gravity and the structure of spacetime," Hohenegger said. If black hole morsels exist, they may not only illuminate the sky with exotic radiation but could also shed light on some of the deepest unsolved questions in physics. Solve the daily Crossword
Yahoo
31-05-2025
- Business
- Yahoo
Infamous 'neutron lifetime puzzle' may finally have a solution — but it involves invisible atoms
When you buy through links on our articles, Future and its syndication partners may earn a commission. A mysterious second flavor of hydrogen atoms — one that doesn't interact with light — may exist, a new theoretical study proposes, and it could account for much of the universe's missing matter while also explaining a long-standing mystery in particle physics. The mystery, known as the neutron lifetime puzzle, revolves around two experimental methods whose results disagree on the average lifetime of free neutrons — those not bound within atomic nuclei — before they decay to produce three other particles: protons, electrons and neutrinos. "There were two kinds of experiments for measuring the neutron lifetime," Eugene Oks, a physicist at Auburn University and sole author of the new study published in the journal Nuclear Physics B, told Live Science in an email. The two methods are called beam and bottle. In beam experiments, scientists count protons left behind immediately after neutrons decay. Using the other approach, in bottle experiments, ultra-cold neutrons are trapped and left to decay, and the remaining neutrons are counted after the experimental run is over — typically lasting between 100 and 1000 seconds, with many such runs performed under varying conditions like trap material, storage time, and temperature to improve accuracy and control for systematic errors. These two methods yield results that differ by about 10 seconds: beam experiments measure a neutron lifetime of 888 seconds, whereas bottle experiments report 878 seconds — a discrepancy well beyond experimental uncertainty. "This was the puzzle," said Oks. In his study, Oks proposes that the discrepancy in lifetimes arises because a neutron sometimes decays not into three particles, but just two: a hydrogen atom and a neutrino. Since the hydrogen atom is electrically neutral, it can pass through detectors unnoticed, giving the false impression that fewer decays have occurred than expected. Although this two-body decay mode had been proposed theoretically in the past, it was believed to be extremely rare — occurring in only about 4 out of every million decays. Oks argues that this estimate is dramatically off because previous calculations didn't consider a more exotic possibility: that most of these two-body decays produce a second, unrecognized flavor of hydrogen atom. And unlike ordinary hydrogen, these atoms don't interact with light. "They do not emit or absorb electromagnetic radiation, they remain dark," Oks explained. That would make them undetectable using traditional instruments, which rely on light to find and study atoms. Related: How many atoms are in the observable universe? What distinguishes this second flavor? Most importantly, the electron in this type of hydrogen would be far more likely to be found close to the central proton than in ordinary atoms, and would be completely immune to the electromagnetic forces that make regular atoms visible. The invisible hydrogen would be hard to detect. "The probability of finding the atomic electron in the close proximity to the proton is several orders of magnitude greater than for ordinary hydrogen atoms," Oks added. This strange atomic behavior comes from a peculiar solution to the Dirac equation — the core equation in quantum physics that describes how electrons behave. Normally, these solutions are considered unphysical, but Oks argues that once the fact that protons have a finite size is taken into account, these unusual solutions start to make sense and describe well-defined particles. By considering a second flavor of hydrogen, Oks calculates that the rate of two-body decays could be enhanced by a factor of about 3,000. This would raise their frequency to around 1% of all neutron decays — enough to explain the gap between beam and bottle experiments. "The enhancement of the two-body decay by a factor of about 3000 provided the complete quantitative resolution of the neutron lifetime puzzle," he said. That's not all. Invisible hydrogen atoms might also solve another cosmic mystery: the identity of dark matter, the unseen material that's thought to make up most of the matter in the universe today. In a 2020 study, Oks showed that if these invisible atoms were abundant in the early universe, they could explain an unexpected dip in ancient hydrogen radio signals observed by astronomers. Since then, he has argued that these atoms may be the dominant form of baryonic dark matter — matter made from known particles like protons and neutrons, but in a form that's hard to detect. "The status of the second flavor of hydrogen atoms as baryonic dark matter is favored by the Occam's razor principle," said Oks, referring to the idea that the simplest explanation is often best. "The second flavor of hydrogen atoms, being based on the standard quantum mechanics, does not go beyond the Standard Model of particle physics." In other words, no exotic new particles or material are needed to explain dark matter — just a new interpretation of atoms that we already thought we understood. Oks is now collaborating with experimentalists to test his theory. At the Los Alamos National Laboratory in New Mexico, a team is preparing an experiment based on two key ideas. First, both flavors of hydrogen can be excited using an electron beam. Second, once excited, ordinary hydrogen atoms can be stripped away using a laser or electric field — leaving behind only the invisible ones. A similar experiment is also being prepared in Germany at the Forschungszentrum Jülich, a national research institute near Garching. RELATED STORIES —Dark matter may have its own 'invisible' periodic table of elements —Scientists may have finally found where the 'missing half' of the universe's matter is hiding —Scientists are one step closer to knowing the mass of ghostly neutrinos — possibly paving the way to new physics The stakes for these tests are high. "If successful, the experiment could yield results this year," said Oks. "The success would be a very significant breakthrough both in particle physics and in dark matter research." In the future, Oks plans to explore whether other atomic systems might also have two flavors, potentially opening the door to even more surprising discoveries. And if confirmed, such findings could also reshape our understanding of cosmic history. "The precise value of the neutron lifetime is pivotal for calculating the amount of hydrogen, helium and other light elements that were formed in the first few minutes of the universe's life," Oks said. So his proposal doesn't just solve a long-standing puzzle — it could rewrite the earliest chapters of cosmic evolution.
