Neutrinos are tiny, mysterious particles with no electric charge and almost no mass. They interact weakly with matter and act as cosmic messengers, helping us understand the universe’s most energetic phenomena and exploring its farthest reaches.
To detect them, scientists use large observatories in water or ice to look for Cherenkov light, a bluish glow that appears when neutrinos interact with nearby particles.
On February 13, 2023, the ARCA detector of the KM3NeT telescope in the deep sea detected a powerful neutrino with an energy of about 220 PeV, the most energetic ever observed. This event, KM3-230213A, shows that such high-energy neutrinos exist in the universe. The KM3NeT team announced this discovery on February 12, 2025.
The detected event was a single muon that passed through the entire detector, triggering signals in over a third of the sensors. Its path and high energy showed it came from a cosmic neutrino interacting near the detector.
Paschal Coyle, KM3NeT Spokesperson, said this discovery opens a new chapter in neutrino astronomy, allowing us to explore extreme astrophysical phenomena.
The KM3NeT neutrino telescope, still being built, will cover more than one cubic kilometer with two detectors, ARCA and ORCA. It uses seawater to detect neutrinos and high-tech optical modules to spot Cherenkov light from neutrino interactions.
Scientists revealed for the first time the origin of neutrinos
Aart Heijboer, KM3NeT Physics, and Software Manager at the time of the detection and researcher at Nikhef National Institute for Subatomic Physics, The Netherlands, said, “To determine the direction and energy of this neutrino required a precise calibration of the telescope and sophisticated track reconstruction algorithms. Furthermore, this remarkable detection was achieved with only one-tenth of the final configuration of the detector, demonstrating the great potential of our experiment for the study of neutrinos and neutrino astronomy.”
Dutch scientists and engineers played a significant role in this discovery. Organizations like Nikhef, NWO-I, the University of Amsterdam, Leiden University, NIOZ, and TNO are part of the KM3NeT collaboration, contributing to design, construction, deployment, system engineering, software development, and data analysis. Their involvement was crucial in achieving this breakthrough.
Jorgen D’Hondt, director of Nikhef, said, “What a wonderful observation. This is promising for the future of this research field. I look forward to the next few years of expanding KM3NeT. That our researchers and technicians are involved in so many parts of this undersea telescope shows the strength of the Nikhef partnership in which theory, experiment, and instrumentation come together.”
Dorothea Samtleben, program leader of the Nikhef Neutrino group and affiliated with Leiden University, added: “The excellent diverse expertise and years of experience of the Nikhef Neutrino group together with the excellence of the Nikhef workshop form a unique, fruitful combination. This allows us to make an important contribution to the KM3NeT collaboration in many different areas – from detector construction to complex reconstruction algorithms – and also inspire many young researchers, engineers, and technicians.”
“Building a neutrino telescope at the bottom of the Mediterranean Sea is only possible through close international cooperation. You need the groundbreaking knowledge of many different experts, building together towards a shared vision. I am enormously proud of our consortium and the result published today,” said Paul de Jong, KM3NeT spokesperson, vice program leader of the Nikhef neutrino group, and professor at the University of Amsterdam.
Journal Reference:
- The KM3NeT Collaboration. Observation of an ultra-high-energy cosmic neutrino with KM3NeT. Nature 638, 376–382 (2025). DOI: 10.1038/s41586-024-08543-1
Source: Tech Explorist
