Latest news with #CubicKilometreNeutrinoTelescope
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
12-02-2025
- Science
- Yahoo
Unfinished deepsea observatory spots highest-energy neutrino ever
A neutrino with 30 times more energy than any previously seen on Earth was detected by an unfinished observatory at the bottom of the Mediterranean Sea after travelling from beyond this galaxy, scientists said Wednesday. Neutrinos are the second most abundant particle in the universe. Known as ghost particles, they have no electric charge, almost no mass and effortlessly pass through most matter -- such as our world or bodies -- without anyone noticing. The most violently explosive events in the universe -- such as a star going supernova, two neutron stars smashing into each other or the almighty suck of supermassive black holes -- create what is called ultra-high-energy neutrinos. Because these particles interact so little with matter, they glide easily away from the violence that created them, travelling in a straight line across the universe. When they finally arrive at Earth, neutrinos serve as "special cosmic messengers" offering a glimpse into the far reaches of the cosmos that is otherwise hidden from our view, Italian researcher Rosa Coniglione said in a statement. However, these ghost particles are extremely difficult to detect. One way is by using water. When light passes through water, it slows down. This sometimes allows quick-moving particles to overtake light -- while still not going faster than the speed of light. When this happens, it creates a bluish glow called "Cherenkov light" that can be detected by extraordinarily sensitive sensors. But to observe this light requires a huge amount of water -- at least one cubic kilometre, the equivalent of 400,000 Olympic swimming pools. That is why the Cubic Kilometre Neutrino Telescope, or KM3NeT, lies at the bottom of the Mediterranean. - Think of a ping pong ball - The European-led facility is still under construction, and spread over two sites. Its ARCA detector, which is interested in astronomy, is nearly 3,500 metres (2.2 miles) underwater off the coast of Sicily. The neutrino-hunting ORCA detector is in the depths near the French city of Toulon. Cables hundreds of metres long equipped with photomultipliers -- which amplify miniscule amounts of light -- have been anchored to the seabed nearby. Eventually 200,000 photomultipliers will be arrayed in the abyss. But the ARCA detector was operating at just a tenth of what will be its eventual power when it spotted something strange on February 13, 2023, according to new research published in the journal Nature. A muon, which is a heavy electron produced by a neutrino, "crossed the entire detector, inducing signals in more than one-third of the active sensors," according to a statement from KM3NeT, which brings together 350 scientists from institutions in 21 countries. The neutrino had an estimated energy of 220 petaelectronvolts -- or 220 million billion electron volts. A neutrino with such a massive amount of energy had never before been observed on Earth. "It is roughly the energy of a ping pong ball falling from one metre height," Dutch physicist and KM3NeT researcher Aart Heijboer told a press conference. "But the amazing thing is that all this energy is contained in one single elementary" particle, he added. For humans to create such a particle would require building the equivalent of a Large Hadron Collider "all around the Earth at the distance of the geostationary satellites", said French physicist Paschal Coyle. - Blazars as source? - With this kind of energy, the event that created this neutrino must have been beyond Milky Way. The exact distance remains unknown, "but what we are quite sure is that it's not coming from our galaxy", said French physicist Damien Dornic. The astrophysicists have some theories about what could have caused such a neutrino. Among the suspects are 12 blazars -- the incredibly bright cores of galaxies with supermassive black holes. But more research is needed. "At the time this event happened, our neutrino alert system was still in development," Heijboer emphasised. If another neutrino is detected near the end of this year, an alert will be sent in seconds to "all the telescopes around the world so that they can point in that direction" to try to spot the source, he said. ber-dl/js
Yahoo
12-02-2025
- Science
- Yahoo
High-energy cosmic neutrino detected under Mediterranean Sea
By Will Dunham (Reuters) - Using an observatory under construction deep beneath the Mediterranean Sea near Sicily, scientists have detected a ghostly subatomic particle called a neutrino boasting record-breaking energy in another important step toward understanding some of the universe's most cataclysmic events. The researchers, part of the KM3NeT (Cubic Kilometre Neutrino Telescope) Collaboration, believe the neutrino came from beyond the Milky Way galaxy. They identified 12 supermassive black holes actively guzzling surrounding matter at the center of distant galaxies as possible origination points, though the neutrino may have arisen from some other source. See for yourself — The Yodel is the go-to source for daily news, entertainment and feel-good stories. By signing up, you agree to our Terms and Privacy Policy. KM3NeT comprises two large neutrino detectors at the bottom of the Mediterranean. One called ARCA - 3,450 meters (2.1 miles) deep near Sicily - is designed to find high-energy neutrinos. One called ORCA - 2,450 meters (1.5 miles) deep near Provence, France - is designed to detect low-energy neutrinos. The newly described "ultra-high energy" neutrino, detected by ARCA in February 2023, was measured at about 120 quadrillion electronvolts, a unit of energy. It was 30 times more energetic than any other neutrino detected to date, a quadrillion times more energetic than particles of light called photons and 10,000 times more energetic than particles made by the world's largest and most powerful particle accelerator, the Large Hadron Collider near Geneva. "It's in a completely unexplored region of energy," said physicist Paschal Coyle of the Marseille Particle Physics Centre (CPPM) in France, one of the leaders of the research published on Wednesday in the journal Nature. "The energy of this neutrino is exceptional," added physicist Aart Heijboer of the Nikhef National Institute for Subatomic Physics in the Netherlands, another of the researchers. Neutrinos offer scientists a different way to study the cosmos, not based on electromagnetic radiation - light. Many aspects of the universe are indecipherable using light alone. Neutrinos are electrically neutral, undisturbed by even the strongest magnetic field, and rarely interact with matter. As neutrinos travel through space, they pass unimpeded through matter - stars, planets or anything else. That makes them "cosmic messengers" because scientists can trace them back to their source, either within the Milky Way or across galaxies, and thus learn about some of the most energetic processes in the cosmos. "Neutrinos are ghost particles. They travel through walls, all the way through the Earth, and all the way from the edge of the universe," Coyle said. "Neutrinos have zero charge, zero size, almost zero mass and almost zero interaction. They are the closest thing to nothing one can imagine, but nevertheless they are key to fully understanding the universe." Other high-energy cosmic messengers zipping through space are not as reliable. For instance, the path of cosmic rays gets bent by magnetic fields, so they cannot be traced back to their place of origination. Detecting neutrinos is not simple, requiring large observatories located deep underwater or in ice. These mediums offer an expansive and transparent volume where a passing neutrino may interact with a particle, producing a flash of light called Cherenkov radiation. The researchers concluded that the one spotted at ARCA - which was a type of neutrino called a muon - was of cosmic origin based on its horizontal trajectory and the fact that it had traversed through about 140 km (87 miles) of rock and seawater before reaching the detector. The KM3NeT detectors are still under construction and have not yet reached their full capabilities. Neutrinos are produced through various astrophysical processes at various energy levels. For instance, low-energy neutrinos are born in nuclear fusion processes inside stars. High-energy neutrinos arise from particle collisions occurring in violent events such as a black hole greedily eating infalling matter or bursts of gamma rays during the explosive deaths of stars. They also can be produced by interactions between high-energy cosmic rays and the universe's background radiation. The study of neutrinos is still in its formative stages. "So why it matters? It's basically just trying to understand what is going on in the cosmos," Heijboer said.
Yahoo
12-02-2025
- Science
- Yahoo
Unfinished deepsea observatory spots highest-energy neutrino ever
A neutrino with 30 times more energy than any previously seen on Earth was detected by an unfinished observatory at the bottom of the Mediterranean Sea after travelling from beyond this galaxy, scientists said Wednesday. Neutrinos are the second most abundant particle in the universe. Known as ghost particles, they have no electric charge, almost no mass and effortlessly pass through most matter -- such as our world or bodies -- without anyone noticing. The most violently explosive events in the universe -- such as a star going supernova, two neutron stars smashing into each other or the almighty suck of supermassive black holes -- create what is called ultra-high-energy neutrinos. Because these particles interact so little with matter, they glide easily away from the violence that created them, travelling in a straight line across the universe. When they finally arrive at Earth, neutrinos serve as "special cosmic messengers" offering a glimpse into the far reaches of the cosmos that is otherwise hidden from our view, Italian researcher Rosa Coniglione said in a statement. However, these ghost particles are extremely difficult to detect. One way is by using water. When light passes through water, it slows down. This sometimes allows quick-moving particles to overtake light -- while still not going faster than the speed of light. When this happens, it creates a bluish glow called "Cherenkov light" that can be detected by extraordinarily sensitive sensors. But to observe this light requires a huge amount of water -- at least one cubic kilometre, the equivalent of 400,000 Olympic swimming pools. That is why the Cubic Kilometre Neutrino Telescope, or KM3NeT, lies at the bottom of the Mediterranean. - Think of a ping pong ball - The European-led facility is still under construction, and spread over two sites. Its ARCA detector, which is interested in astronomy, is nearly 3,500 metres (2.2 miles) underwater off the coast of Sicily. The neutrino-hunting ORCA detector is in the depths near the French city of Toulon. Cables hundreds of metres long equipped with photomultipliers -- which amplify miniscule amounts of light -- have been anchored to the seabed nearby. Eventually 200,000 photomultipliers will be arrayed in the abyss. But the ARCA detector was operating at just a tenth of what will be its eventual power when it spotted something strange on February 13, 2023, according to new research published in the journal Nature. A muon, which is a heavy electron produced by a neutrino, "crossed the entire detector, inducing signals in more than one-third of the active sensors," according to a statement from KM3NeT, which brings together 350 scientists from institutions in 21 countries. The neutrino had an estimated energy of 220 petaelectronvolts -- or 220 million billion electron volts. A neutrino with such a massive amount of energy had never before been observed on Earth. "It is roughly the energy of a ping pong ball falling from one metre height," Dutch physicist and KM3NeT researcher Aart Heijboer told a press conference. "But the amazing thing is that all this energy is contained in one single elementary" particle, he added. For humans to create such a particle would require building the equivalent of a Large Hadron Collider "all around the Earth at the distance of the geostationary satellites", said French physicist Paschal Coyle. - Blazars as source? - With this kind of energy, the event that created this neutrino must have been beyond Milky Way. The exact distance remains unknown, "but what we are quite sure is that it's not coming from our galaxy", said French physicist Damien Dornic. The astrophysicists have some theories about what could have caused such a neutrino. Among the suspects are 12 blazars -- the incredibly bright cores of galaxies with supermassive black holes. But more research is needed. "At the time this event happened, our neutrino alert system was still in development," Heijboer emphasised. If another neutrino is detected near the end of this year, an alert will be sent in seconds to "all the telescopes around the world so that they can point in that direction" to try to spot the source, he said. ber-dl/js
Reuters
12-02-2025
- Science
- Reuters
High-energy cosmic neutrino detected under Mediterranean Sea
Summary Detection was made 3,450 meters (2.1 miles) underwater Scientists try to determine where neutrino originated Studying neutrinos have provide new insight in astronomy Feb 12 (Reuters) - Using an observatory under construction deep beneath the Mediterranean Sea near Sicily, scientists have detected a ghostly subatomic particle called a neutrino boasting record-breaking energy in another important step toward understanding some of the universe's most cataclysmic events. The researchers, part of the KM3NeT (Cubic Kilometre Neutrino Telescope) Collaboration, believe the neutrino came from beyond the Milky Way galaxy. They identified 12 supermassive black holes actively guzzling surrounding matter at the center of distant galaxies as possible origination points, though the neutrino may have arisen from some other source. KM3NeT comprises two large neutrino detectors at the bottom of the Mediterranean. One called ARCA - 3,450 meters (2.1 miles) deep near Sicily - is designed to find high-energy neutrinos. One called ORCA - 2,450 meters (1.5 miles) deep near Provence, France - is designed to detect low-energy neutrinos. The newly described "ultra-high energy" neutrino, detected by ARCA in February 2023, was measured at about 120 quadrillion electronvolts, a unit of energy. It was 30 times more energetic than any other neutrino detected to date, a quadrillion times more energetic than particles of light called photons and 10,000 times more energetic than particles made by the world's largest and most powerful particle accelerator, the Large Hadron Collider near Geneva. "It's in a completely unexplored region of energy," said physicist Paschal Coyle of the Marseille Particle Physics Centre (CPPM) in France, one of the leaders of the research published on Wednesday in the journal Nature, opens new tab. "The energy of this neutrino is exceptional," added physicist Aart Heijboer of the Nikhef National Institute for Subatomic Physics in the Netherlands, another of the researchers. Neutrinos offer scientists a different way to study the cosmos, not based on electromagnetic radiation - light. Many aspects of the universe are indecipherable using light alone. Neutrinos are electrically neutral, undisturbed by even the strongest magnetic field, and rarely interact with matter. As neutrinos travel through space, they pass unimpeded through matter - stars, planets or anything else. That makes them "cosmic messengers" because scientists can trace them back to their source, either within the Milky Way or across galaxies, and thus learn about some of the most energetic processes in the cosmos. "Neutrinos are ghost particles. They travel through walls, all the way through the Earth, and all the way from the edge of the universe," Coyle said. "Neutrinos have zero charge, zero size, almost zero mass and almost zero interaction. They are the closest thing to nothing one can imagine, but nevertheless they are key to fully understanding the universe." Other high-energy cosmic messengers zipping through space are not as reliable. For instance, the path of cosmic rays gets bent by magnetic fields, so they cannot be traced back to their place of origination. Detecting neutrinos is not simple, requiring large observatories located deep underwater or in ice. These mediums offer an expansive and transparent volume where a passing neutrino may interact with a particle, producing a flash of light called Cherenkov radiation. The researchers concluded that the one spotted at ARCA - which was a type of neutrino called a muon - was of cosmic origin based on its horizontal trajectory and the fact that it had traversed through about 140 km (87 miles) of rock and seawater before reaching the detector. The KM3NeT detectors are still under construction and have not yet reached their full capabilities. Neutrinos are produced through various astrophysical processes at various energy levels. For instance, low-energy neutrinos are born in nuclear fusion processes inside stars. High-energy neutrinos arise from particle collisions occurring in violent events such as a black hole greedily eating infalling matter or bursts of gamma rays during the explosive deaths of stars. They also can be produced by interactions between high-energy cosmic rays and the universe's background radiation. The study of neutrinos is still in its formative stages. "So why it matters? It's basically just trying to understand what is going on in the cosmos," Heijboer said.
