This discovery, published in the scientific journal Nature, unveils a new way to observe the Universe. This achievement is the result of the international scientific collaboration KM3NeT, which includes the IGIC Research Institute at Campus Gandia of the Universitat Politècnica de València, along with the Joint Unit with the Spanish Institute of Oceanography.
Two years ago, the ARCA detector of the KM3NeT underwater neutrino telescope recorded an extraordinary deep-sea event linked to a neutrino with an estimated energy of approximately 220 PeV (220 × 10¹⁵ electron volts or 220,000 trillion electron volts).
This event, named KM3-230213A, is the most energetic neutrino ever detected and offers the first evidence that neutrinos of such extreme energies are generated in the Universe. After years of meticulous analysis and interpretation of experimental data, on February 12, 2025, the international KM3NeT scientific collaboration—including researchers from the IGIC Institute at Campus Gandia of the Universitat Politècnica de València and the IEO-UPV Joint Unit of the Spanish Institute of Oceanography (CSIC-UPV)—published the details of this groundbreaking discovery in Nature.
The Campus Gandia team, led by Miguel Ardid, has been involved in KM3NeT since its inception in 2006, when the design of the infrastructure began. The team conducts R&D in both the technological aspects, focusing primarily on the acoustic and positioning systems of the underwater detector, and in astroparticle physics analysis.
“We anticipated that KM3NeT would make groundbreaking discoveries, but we didn’t expect them to come so early with a partial detector configuration. Moreover, it was a stroke of luck—double luck for UPV—since the ultra-energetic neutrino was detected precisely during the operation of the detector built by UPV,” explains Ardid.
Paschal Coyle, KM3NeT spokesperson at the time of the detection and researcher at the IN2P3/CNRS Centre National de la Recherche Scientifique – Centre de Physique des Particules de Marseille (France), emphasizes that KM3NeT has begun exploring a range of energy and sensitivity where the detected neutrinos are likely produced by extreme astrophysical phenomena. “This first detection of a neutrino with hundreds of PeV opens a new chapter in neutrino astronomy and provides a new window for observing the Universe,” he emphasized.
Black Holes, Supernovae, and Gamma-Ray Bursts
The high-energy Universe is home to colossal phenomena, including supermassive black holes at the centers of certain galaxies, supernova explosions, and gamma-ray bursts—extraordinary events that remain only partially understood. These powerful cosmic accelerators produce streams of particles known as cosmic rays. Some cosmic rays can interact with surrounding matter or photons, producing neutrinos and photons. As the most energetic cosmic rays travel through the Universe, they may also collide with photons from the cosmic microwave background radiation, resulting in the production of extremely high-energy neutrinos known as “cosmogenic” neutrinos.
“The scale of KM3NeT, which will eventually encompass a volume of around one cubic kilometer with about 200,000 photomultipliers in total, along with its extreme location in the depths of the Mediterranean Sea, highlights the extraordinary efforts required to advance neutrino astronomy and particle physics. The detection of this event is the outcome of an extraordinary collaborative effort, bringing together numerous international teams of engineers, technicians, and scientists,” adds Miles Lindsey Clark, Technical Director of the KM3NeT project at the time of the detection and research engineer at IN2P3/CNRS – Laboratory of Astroparticles and Cosmology, France.
The KM3NeT Collaboration unites over 360 scientists, engineers, technicians, and students from 68 institutions across 22 countries worldwide. In Spain, in addition to the IGIC at the Universitat Politècnica de València, the following institutions are also involved: IFIC (Institute of Corpuscular Physics, a joint center of the Universitat de València and CSIC), the University of Granada, the IEO-UPV Joint Unit of the Spanish Institute of Oceanography (CSIC-UPV), and the LAB at the Universitat Politècnica de Catalunya. Their research is funded by the Ministry of Science, Innovation, and Universities, as well as by European and regional programs, including the Generalitat Valenciana and the Junta de Andalucía.
“The field of neutrino astronomy is experiencing rapid growth. We are confident that with the full deployment of the two KM3NeT detectors, ARCA and ORCA, we will gain new insights into the mystery of the origin of cosmic neutrinos,” conclude the group of Spanish researchers involved in KM3NeT.
Source: Luis Zurano, Scientific Communication Unit of the Universitat Politècnica de València
