Latest news with #KM3NeT
Yahoo
2 days ago
- Science
- Yahoo
A Ghost Particle Flew Through Earth. It Might Have Come From Dark Matter.
"Hearst Magazines and Yahoo may earn commission or revenue on some items through these links." Here's what you'll learn when you read this story: In February of 2023, the Cubic Kilometer Neutrino Telescope (KM3NeT) detected a neutrino some 35 times higher in energy than any previous detection. A new study posits that this muon might be the result of a dark matter particle that decayed as it passed through the Earth, which would also explain why the IceCube Observatory in the South Pole hasn't detected any such particle. For now, the most likely explanation is that the particle is just a high-energy neutrino, but we're likely to learn more about these elusive particles when KM3NeT is fully online. In the middle of the night on February 13, 2023, the Astroparticle Research with Cosmics in the Abyss (ARCA) array—part of the larger Cubic Kilometer Neutrino Telescope (KM3NeT), located in the Mediterranean off the coast of Italy—detected a high-energy particle unlike any other. After crunching the numbers for two years, scientists earlier this year announced that this particle likely originated from a blazar, and was the highest-energy neutrino ever detected by a factor of 35. Even more impressive, the array documented this particle while it was only partially finished. However, there was one strange attribute of this neutrino event, which was dubbed KM3-230213A—the IceCube Neutrino Observatory in the South Pole has never recorded such an event, and did not detect this high-energy event, either. Now, a new study (posted to the preprint server arXiv) suggests that one way to resolve this conundrum is to consider if the ultra-energetic muon neutrino was actually produced by dark matter. 'It opens up a new way you can really test dark matter,' Bhupal Dev, lead author of the study from Washington University, said to New Scientist. 'We can convert these neutrino telescopes into dark matter detectors.' Because KM3-230213A traveled along a shallow path as it passed through out planet, it likely flew through more of the Earth's crust than it takes for neutrinos to reach IceCube—and that might be the key. The researchers tried to recreate a dark matter scenario that KM3NeT could detect, but IceCube could not. 'We propose a novel solution to this conundrum in terms of dark matter (DM) scattering in the Earth's crust,' the paper reads. 'We show that intermediate dark-sector particles that decay into muons are copiously produced when high-energy (∼100 PeV) DM propagates through a sufficient amount of Earth overburden.' So, the high-energy particle wasn't directly a dark matter particle, but rather a muon that decayed from dark matter likely fired from a blazar (a type of active galactic nucleus) right at Earth. As the paper notes, this is just one of many theories that have propagated since KM3NeT announced the discovery of the particle. These ideas suggest, according to the paper, that the particle could be 'decaying heavy DM, primordial black hole evaporation, Lorentz invariance violation, neutrino non-standard interactions.' The KM3NeT collaboration has detailed how the ARCA array—along with the Oscillation Research with Cosmics in the Abyss (ORCA) array—could provide indirect observations of dark matter similar to this event. However, other physicists speaking with New Scientist said that the most likely explanation (at least, as of right now) is that KM3-230213A is simply a high-energy neutrino, and not evidence of decaying dark matter. While hypotheses proliferate, scientists are still working with a sample size of one. But with K3MNeT finishing construction by the end of the decade, that likely won't be the case for long. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Hans India
6 days ago
- Science
- Hans India
Mysterious particle pierces earth, hinting at possible first direct dark matter detection
In February 2023, an underwater telescope anchored deep in the Mediterranean Sea—known as KM3NeT—recorded the brightest particle event ever seen. A stunning flash of light pierced through the detector's sensor network, revealing an object carrying a staggering 220 peta-electronvolts (PeV) of energy—nearly 100 times more powerful than anything produced by the Large Hadron Collider. Initially believed to be an ultra-energetic neutrino, this high-energy particle earned the nickname 'impossible muon' because of how unusually bright it was—35 times brighter than any prior detection. But soon, scientists hit a snag: its cousin observatory, IceCube in Antarctica—larger and operational for over a decade—had no record of a similar event, even though it had clear access to the same region of the sky. This anomaly led researchers to entertain a revolutionary idea: the flash could be humanity's first direct evidence of dark matter—the mysterious, invisible material believed to make up five times more mass than ordinary matter in the universe. Their theory suggests that the particle may have originated from a blazar—a galaxy with a supermassive black hole ejecting high-speed jets of particles. If those jets contain dark matter particles, they could survive billion-year journeys through space. The particle that struck KM3NeT came from a direction populated by known blazars, lending weight to the hypothesis. As the beam traveled sideways through Earth, it pierced 93 miles (150 km) of rock before reaching KM3NeT. Scientists theorize that during this underground trek, a dark matter particle might have collided with a nucleus, briefly becoming an 'excited' state that quickly decayed into two tightly aligned muons. KM3NeT's detectors, unable to distinguish the twin paths, saw a single blazing track. In contrast, IceCube—due to its South Pole location—would have seen the particle pass through only 9 miles (15 km) of crust. With less matter in its path, a collision (and thus detection) was far less likely. Not all physicists are convinced. Some argue the simplest explanation is still a record-breaking neutrino. Others, like Shirley Li of UC Irvine, note that while the dark matter model predicts a pair of overlapping muons, current instruments can't resolve such fine detail at these extreme energies—yet. Regardless of the outcome, the discovery has reignited the global pursuit to uncover what dark matter is made of. As KM3NeT expands and IceCube undergoes planned upgrades, scientists will continue watching the skies—and seas—for answers. Whether this was a neutrino anomaly or the long-sought dark matter breakthrough, one underwater flash may have just opened a new chapter in modern physics.
Gizmodo
03-06-2025
- Business
- Gizmodo
Physicists Propose Cheaper Alternative to Particle Colliders: Supermassive Black Holes
A new study from Johns Hopkins University suggests that supermassive black holes—those cosmic behemoths lurking at the centers of galaxies—might already be generating the kinds of high-energy particle collisions researchers have spent decades trying to recreate here on Earth. Published today in Physical Review Letters, the study proposes that certain spinning black holes could serve as natural particle accelerators, rivaling or even exceeding the capabilities of the Large Hadron Collider (LHC). That's a big deal, especially as funding for fundamental physics research grows increasingly scarce in the United States, and plans for next-generation colliders stretch far into the future. For about a decade, experts have theorized that supermassive black holes could do this, co-author Andrew Mummery, a theoretical physicist at the University of Oxford, told Gizmodo. But his study attempted to validate this theory by looking for naturally-occurring scenarios that would give rise to a black hole's supercollider-like behavior. Understanding how this happens could provide a new avenue for research on dark matter and other elusive particles. 'One of the great hopes for particle colliders like the Large Hadron Collider is that it will generate dark matter particles, but we haven't seen any evidence yet,' explained co-author Joseph Silk, an astrophysicist at Johns Hopkins University, the University of Oxford, and the Institute of Astrophysics in Paris, in a Johns Hopkins release. 'That's why there are discussions underway to build a much more powerful version, a next-generation supercollider,' Silk said. 'But as we invest $30 billion and wait 40 years to build this supercollider—nature may provide a glimpse of the future in super massive black holes.' At the LHC, protons are smashed together at near-light speeds to uncover the building blocks of reality—and hopefully, to catch a glimpse of dark matter, the mysterious stuff that makes up about 85% of the universe's mass. But it turns out black holes might already be producing these elusive particles in the wild. Some supermassive black holes spin so rapidly that they can fling out jets of plasma at astonishing speeds. In their new study, Mummery and Silk modeled what happens near the edge of these spinning monsters, where violent gas flows can whip particles into chaotic collisions, much like a human-built collider does. 'Some particles from these collisions go down the throat of the hole and disappear forever,' Silk said, 'But because of their energy and momentum, some also come out, and it's those that come out which are accelerated to unprecedentedly high energies.' These ultra-energetic particles zipping through space could, in theory, be picked up by Earth-based observatories like IceCube in Antarctica or the KM3NeT telescope beneath the Mediterranean Sea, both of which already detect ghostly particles called neutrinos. Earlier this year, KM3NeT researchers announced the detection of the most energetic neutrino yet, a potential step forward in understanding the behavior of these ephemeral and energetic particles. Equipped with a deeper understanding of how these high-energy particles might form at the edges of supermassive black holes, Mummery now aims to investigate their nature. Figuring out what, exactly, escapes from these cosmic voids could offer a cost-effective, naturally occurring complement to traditional colliders. The approach could yield a new path toward uncovering the nature of dark matter.
Yahoo
16-05-2025
- Science
- Yahoo
Why scientists are so excited about the highest-energy 'ghost particle' ever seen
When you buy through links on our articles, Future and its syndication partners may earn a commission. Earlier this year, an underwater detector in the Mediterranean Sea found the most energetic neutrino to date. And scientists are still talking about it because, well, this discovery could be a really big deal. Not only could this neutrino, also known as a "ghost particle," have been fleeing a gamma-ray burst or a supermassive black hole, but it could also have been produced by an ultra-powerful cosmic ray interacting with the cosmic microwave background (CMB). That latter bit which we'll get to soon, could be huge. Moreover, the detector that pinpointed this particle isn't even totally built yet — once put together, who knows what it can accomplish. "We're excited to have observed this event and we're hungry and curious for more," KM3NeT's spokesperson, Paul de Jong of the University of Amsterdam, told For some background, the neutrino was detected on February 13, 2023 by the European Union-funded KM3NeT, the Cubic Kilometre Neutrino Telescope. Neutrinos are ghostly particles because they have very little mass and rarely interact with other forms of matter, making them very difficult to detect. Trillions of neutrinos are passing through your body every second, yet you cannot tell. Scientists have to be patient to spot even one neutrino. Modern neutrino detectors are placed in water, and particularly in the dark. Sometimes that water is held in a tank, as was the case with the Sudbury Neutrino Observatory in Canada, as well as with Super-Kamiokande in Japan. Other times, that water is frozen in the ground, as in the case of the IceCube Neutrino Observatory at the South Pole. But it's also possible for neutrino detectors to literally be dipped into the sea, as is the case with KM3NeT, which extends as deep as 2.17 miles (3.5 kilometers) below the waves. The reason water is so important is that, occasionally, a neutrino will interact with a molecule of water. The energies involved can be so great that the collision smashes the water molecule apart into a bunch of daughter nuclei and particles, specifically muons. The muons travel quickly, almost as fast as light in a vacuum, and definitely faster than light through water — the refractive index of water slows light down to approximately 738,188,976 feet per second (225,000,000 meters per second) compared to 983,571,056 feet per second (299,792,458 meters per second) in a vacuum. Because the muons travel faster than light in water, they give off the equivalent of a sonic boom in the form of a flash of light. This light is called Cherenkov radiation. KM3NeT consists of two detectors. The first, called ORCA, is 8,038 feet (2,450 meters) deep off the coast of France and is designed to study how neutrinos oscillate between different types of neutrinos. The other, aka the detector that spotted the new energetic neutrino — which has been catalogued as KM3-230213A — is called ARCA and is located off the coast of Sicily. Both ARCA and ORCA are still under construction. When complete, ARCA will feature 230 vertical detection lines descending into the sea. Each will be lined with 18 optical modules containing 31 photomultiplier tubes that can spot flashes of Cherenkov radiation in the darkness at those depths. At the time that ARCA detected KM3-230213A, only 21 of its detection lines were in operation. The muon ARCA detected had an energy of 120 PeV (1,000 trillion, or quadrillion, electronvolts), which implies the neutrino that produced it must have had a record-breaking energy of 220 PeV. This is 100 quadrillion times more energetic than visible-light photons, and 30 times more energetic than the neutrino that held the previous energy record. Muons can travel several miles through the sea before being absorbed, and KM3NeT detected the muon traveling horizontally rather than straight down to the sea floor. "The horizontal direction on the muon is very relevant," said de Jong. Muons can also be formed in cosmic-ray spallation, wherein a cosmic ray enters Earth's atmosphere and collides with a molecule or atom, smashing it apart into a shower of subatomic particles. Muons formed in this manner can either reach the surface or enter the ocean while traveling straight down — not horizontally. To have been moving horizontally, the muon must have instead "been created close to the detector, and the only realistic scenario is that it was created by a high-energy neutrino," said de Jong. A neutrino of 220 PeV is unprecedented. No environment or object known in our Milky Way galaxy could have produced a neutrino with so much energy. That means its origin must be extragalactic, perhaps created in the violence of a star exploding and producing a gamma-ray burst, or a supermassive black hole ripping a star or gas cloud to shreds with its titanic gravitational tidal forces. Because neutrinos are not deflected by magnetic fields or by gravity, their direction of travel leads back to their source. "The muon direction is almost identical to the direction of the original neutrino, so we can play the game of pointing it back to its cosmic origin," said de Jong. That origin is somewhere in the direction of the constellation of Orion, the Hunter. However, while there are numerous active galaxies with supermassive black holes in that region, none of them was displaying activity at the time that could explain the neutrino, nor was a gamma-ray burst detected from that direction at that time. But another intriguing possibility is that KM3-230213A is the first "cosmogenic" neutrino to be discovered, produced when an ultra-high-energy cosmic ray smashes into a photon belonging to the cosmic microwave background, which is the residual light released 379,000 years after the Big Bang. It would take an extremely energetic cosmic ray to be able to produce a neutrino like KM3-230213A. Cosmic rays in excess of 100,000 PeV have been detected by the likes of the Pierre Auger Observatory in Argentina. Their origins are uncertain, but, in theory every time such a cosmic ray encounters a CMB photon, the collision can produce neutrinos as energetic as KM3-230213A. The greater the cosmic-ray energy, the greater its interaction cross-section, meaning it is more likely to interact with CMB photons. The constant interactions between cosmic rays and CMB photons slows the cosmic ray, limiting their kinetic energy. This is called the Greisen–Zatsepin–Kuzmin (GZK) limit. Related Stories: — Scientists detect highest-energy ghost particle ever seen — where did it come from? — Black holes snacking on small stars create particle accelerators that bombard Earth with cosmic rays — Einstein wins again! Quarks obey relativity laws, Large Hadron Collider finds The possibility of a cosmogenic neutrino excites de Jong. "It would be the very first observation of a cosmogenic neutrino, and it would be the first confirmation of the GZK cut-off outside charged cosmic rays — and even there the proof is ambiguous," he said. Furthermore, the energy of cosmogenic neutrinos can reveal the properties of these ultra-high-energy cosmic rays. This parameter is key for discovering whether such phenomena are made of just protons or heavier atomic nuclei — and, therefore, what produces them. Although KM3-230213A was the only extremely high energy neutrino detected by KM3NeT, there will undoubtedly be many more passing through Earth that go undetected. Does KM3NeT's early detection with ARCA bode well for finally being able to detect such neutrinos more regularly? "We certainly hope so!" said de Jong. "But realistically, other experiments such as IceCube have been taking data for longer and have not observed such an event, so we could simply have been lucky." The discovery was described in a paper published on Feb. 12 in the journal Nature.
Yahoo
12-03-2025
- Science
- Yahoo
A single particle in the deep sea could prove Stephen Hawking right about the early universe
When you buy through links on our articles, Future and its syndication partners may earn a commission. Five decades ago, famed astrophysicist Stephen Hawking theorized that the Big Bang may have flooded the universe with tiny black holes. Now, researchers believe they may have seen one explode. In Feb. 2025, the European collaboration KM3NeT — which consists of underwater detectors off the coasts of France, Italy and Greece — announced the discovery of a stupendously powerful neutrino. This ghostly particle had an energy of around 100 PeV — over 25 times more energetic than the particles accelerated in the Large Hadron Collider, the world's most powerful atom smasher. Physicists have struggled to come up with an explanation for such an energetic neutrino. But now, a team of researchers who were not involved in the original detection have proposed a surprising hypothesis: The neutrino is the signature of an evaporating black hole. The team described their proposal in a paper that was uploaded to the arXiv database and has not been peer-reviewed yet. In the 1970s, Hawking realized that black holes aren't entirely black. Instead, through complex interactions between the black hole event horizon and the quantum fields of space-time, they can emit a slow-but-steady stream of radiation, now known as Hawking radiation. This means black holes evaporate and eventually disappear. In fact, as the black hole gets smaller, it emits even more radiation, until it essentially explodes in a firestorm of high-energy particles and radiation — like the neutrino spotted by the KM3Net collaboration. Related: Stephen Hawking's black hole radiation paradox could finally be solved — if black holes aren't what they seem But all known black holes are very large — at least a few times the mass of the sun, and often significantly larger. It will take well over 10^100 years for even the smallest known black holes to die. If the KM3NeT neutrino is due to an exploding black hole, it has to be much smaller — somewhere around 22,000 pounds (10,000 kilograms). That's about as heavy as two fully grown African elephants, compressed into a black hole smaller than an atom. The only known potential way to produce such tiny black holes is in the chaotic events of the early Big Bang, which may have flooded the cosmos with "primordial" black holes. The smallest primordial black holes produced in the Big Bang would have exploded long ago, while larger ones might persist to the present day. Unfortunately, a 22,000-pound black hole should not survive all the way from the Big Bang to the present day. But the authors pointed out that there might be an additional quantum mechanism — known as "memory burden" — that allows black holes to resist decay. This would allow a 22,000-pound black hole to survive for billions of years before it finally exploded, sending a high-energy neutrino toward Earth in the process. RELATED STORIES —Unproven Einstein theory of 'gravitational memory' may be real after all, new study hints —'Cosmic Horseshoe' may contain black hole the size of 36 billion suns — one of the largest ever detected —Scientists may have just discovered 300 of the rarest black holes in the universe Primordial black holes might be an explanation for dark matter — the invisible substance that accounts for most of the matter in the universe — but so far, searches for them have turned up empty. This new insight may provide an intriguing clue. The researchers found that if primordial black holes of this mass range are abundant enough to account for all the dark matter, they should be exploding somewhat regularly. They estimated that if this hypothesis is correct, the KM3NeT collaboration should see another showstopping neutrino in the next few years. If that detection happens, then we may just have to radically rethink the way we approach dark matter, high-energy neutrinos and even the physics of the early universe.
