Francis Halzen, who today won the 2026 Nobel Prize in Physics, was the driving force behind IceCube, the pioneering kilometre-sized neutrino observatory at the South Pole.

But Halzen — whom I have had the fortune to interview multiple times over the years while covering this field — never saw neutrino detectors such as IceCube as working in isolation.

The dream for many neutrino researchers — and the ultimate story for some reporters such as myself to tell — is to spot phenomena simultaneously with other types of observatories, in a feat of ’multi-messenger astronomy’.

Ever-more sophisticated telescopes allow astronomers to observe the Universe with electromagnetic signals beyond visible light: everything from γ-rays all the way down to long-wavelength radio.

Neutrinos — and high-energy cosmic rays, which are mostly protons — add a whole other ‘sense’. They enable researchers to observe and even build images with particles of matter instead of radiation. The idea is that ordinary, or ‘electromagnetic’, astronomy is only one of the many dimensions that can give a fuller picture of the Universe. Cosmic phenomena such as the supernova explosions of stars or the sudden flares of activity around supermassive black holes should spew out electromagnetic radiation but also neutrinos and other particles of matter.

IceCube made its first ‘multi-messenger’ discovery in 2017, when it detected the neutrino labelled TXS 0506+056, also known as ‘Texas’. It was the first time that a high-energy neutrino was successfully traced back to a source — in this case, a blazar, a galaxy with an intense source of γ-rays.

That year, astronomers experienced an equally momentous multi-messenger event called a kilonova, the collision of two neutron stars. The kilonova was first spotted using yet another sense — the detection of gravitational waves, which are perturbations in the geometry of space. I was lucky to cover both the Texas event and the kilonova.