Level 1 - Absolute Beginner

Scientists found a very powerful particle from space. It is called a neutrino. It hit a special detector under the sea.

The particle hit the KM3NeT detector in the Mediterranean Sea. It had more energy than any neutrino ever found before.

Scientists think the particle came from very far away in space. It may have come from a type of black hole called a blazar. This is a very important discovery.

neutrino

a tiny particle from space that can pass through almost any material

detector

a machine that can find and measure particles or radiation

energy

the power that makes things move, heat up, or change

Mediterranean Sea

the large sea surrounded by Europe, Africa, and Asia

blazar

a type of black hole that shoots a powerful beam of energy directly toward Earth

scientist

a person who studies the natural world and does research experiments

particle

a very small piece of matter, often far too small to see

discovery

finding or learning something new for the first time

Level 2 - Elementary

Scientists may have found where the most powerful particle ever detected came from. The particle, called a neutrino, was caught by the KM3NeT detector in the Mediterranean Sea on February 13, 2023.

The neutrino had an energy of 220 PeV. This is more than 30 times greater than the energy of any neutrino previously recorded. Scientists named it KM3-230213A based on when it was detected.

New research published in May 2026 suggests the particle came from a blazar, a special type of galaxy where a supermassive black hole shoots a beam of energy directly toward Earth. Scientists are still working to confirm the exact source, but the evidence is very strong.

neutrino

a nearly massless particle that travels at close to the speed of light and passes through matter easily

PeV

petaelectronvolt, a unit of energy in particle physics equal to one thousand million million electron volts

Cherenkov light

a faint blue glow produced when a particle moves faster than light through water or ice

blazar

a very energetic type of galaxy where a black hole shoots a powerful jet of energy toward Earth

cosmic ray

a high-energy particle traveling through space, often from a distant galaxy

active galactic nucleus

the energetic central region of a galaxy powered by a supermassive black hole consuming surrounding matter

multi-messenger astronomy

studying space by combining different signals such as light, neutrinos, and gravitational waves

electron volt

a very small unit of energy used in particle physics

Level 3 - Intermediate

The most energetic particle ever detected has found a potential cosmic origin, according to new research published in May 2026. The particle, a neutrino named KM3-230213A, struck the KM3NeT underwater detector array in the Mediterranean Sea on February 13, 2023, carrying a staggering energy of 220 PeV, equivalent to 220 million billion electron volts.

KM3NeT, a network of light sensors spread across the seafloor near Sicily and France, detected the particle as it produced a faint flash of blue Cherenkov light while traveling through the water. Previous high-energy neutrino records had been held by the IceCube telescope buried in Antarctic ice at the South Pole, making the Mediterranean detection a landmark moment for European deep-sea physics.

The May 2026 study suggests the neutrino most likely originated from a blazar, a type of active galactic nucleus where a supermassive black hole fires a jet of high-energy particles directly toward Earth. In such environments, protons accelerated to extreme speeds produce secondary particles, including neutrinos and gamma rays, when they collide with surrounding light and gas. If confirmed, the KM3NeT finding would represent the first direct link between a specific blazar and an extreme-energy neutrino event in modern astrophysics.

Cherenkov radiation

the blue light emitted when a charged particle moves faster than light in a medium such as water

ultra-high-energy

describing particles with energies far above those of typical cosmic rays

active galactic nucleus

the intensely bright core of a galaxy powered by a supermassive black hole actively consuming surrounding matter

photo-meson process

a particle physics interaction where a high-energy proton collides with a photon to produce pions and other particles

multi-messenger astronomy

using different types of cosmic signals simultaneously to study astrophysical events and their sources

cosmogenic

describing particles or phenomena that originate from interactions with background radiation filling the cosmos

landmark

describing a discovery or event of major and lasting historical or scientific importance

relativistic jet

a beam of plasma launched from a black hole at speeds close to the speed of light

Level 4 - Advanced

The identification of a plausible astrophysical source for KM3-230213A, the 220-petaelectronvolt neutrino captured by the KM3NeT/ARCA array off the coast of Sicily in February 2023, moved from speculation toward probabilistic candidate mapping in research amplified by ScienceDaily on May 23, 2026. The particle's energy is roughly 30 times greater than the highest-energy neutrino previously recorded by the IceCube Neutrino Observatory at the Amundsen-Scott South Pole Station, placing it firmly in the category of ultra-high-energy cosmic neutrinos whose origin mechanisms remain among the most fiercely contested questions in astrophysics.

The leading hypothesis, supported by multi-messenger cross-correlation with catalogued blazar positions, proposes that KM3-230213A was produced in the relativistic jet of an active galactic nucleus oriented along the line of sight to Earth, satisfying the defining criterion of a blazar. In such environments, protons accelerated to ultra-high energies in the magnetically turbulent jet base interact via photo-meson or proton-proton processes with photon fields or dense gas, generating secondary pions that decay to neutrinos and gamma rays. The coincidence between the neutrino's reconstructed arrival direction and known blazar positions reaches roughly 3-sigma statistical significance, not yet at the 5-sigma discovery threshold but sufficient to motivate targeted follow-up observations.

A competing hypothesis invokes a cosmogenic origin: the Greisen-Zatsepin-Kuzmin mechanism, by which cosmic-ray protons traveling at near-light speed interact with cosmic microwave background photons to produce pions and cascade neutrinos. A 220 PeV neutrino sits at the upper edge of the energy range predicted by GZK cascade models, implying either an unusually nearby ultra-high-energy cosmic-ray source or a spectrum softer than standard composition models suggest. Discriminating between the blazar and cosmogenic hypotheses hinges on whether KM3NeT accumulates additional ultra-high-energy events from consistent sky positions, a goal motivating the planned expansion of the ARCA subarray from 6 to 230 detection units.

The broader significance lies in its contribution to multi-messenger astrophysics, the programme of correlating gravitational waves, neutrinos, photons, and cosmic rays to triangulate the locations and physical processes of extreme-energy sources. KM3-230213A joins a small cohort of published ultra-high-energy neutrino candidates with plausible directional associations, and its Mediterranean provenance offers a complementary northern-hemisphere field of view to IceCube's southern polar geometry, substantially improving coverage of the Galactic Centre and the rich blazar populations in the northern extragalactic sky.

photo-meson production

the process where a high-energy photon and a proton interact to produce pions and other secondary particles

Greisen-Zatsepin-Kuzmin mechanism

the GZK process by which cosmic-ray protons lose energy interacting with cosmic microwave background photons, producing secondary neutrinos