Neutrinos are extremely lightweight and electrically neutral particles that rarely interact with ordinary matter. Due to these rare interactions, neutrinos can travel across space almost entirely unaffected, carrying information about highly energetic cosmological events, such as exploding stars or supermassive black holes.

The KM3NeT neutrino telescope, an observatory located at the bottom of the Mediterranean Sea, recently detected the presence of a neutrino carrying extremely high energy, above 100 PeV (peta-electronvolts). This is one of the most energetic neutrinos observed to date.

Theoretical predictions suggested that another large-scale neutrino detector, namely the IceCube detector, would also observe similar high-energy neutrino events. However, this did not happen, which might potentially hint at some new physics, such as a new type of neutrinos or non-standard interactions, that are not included in the standard model of physics.