Francis Halzen wins 2026 Nobel Prize in Physics for neutrino observatory work

Francis Halzen won the Nobel Prize in Physics on Tuesday for his contributions to the IceCube Neutrino Observatory and his discovery of high-energy neutrinos of astrophysical origin, NPR reported. The Royal Swedish Academy of Sciences announced the award in Stockholm. The BBC reported he won for a 'decisive contribution' to developing the observatory, and quoted the academy saying his 'vision and scientific leadership have been fundamental for the IceCube Neutrino Observatory'.

Halzen was born in Belgium, is 82 years old and is affiliated with the University of Wisconsin–Madison in the US, according to NPR; the BBC reported he is now a US citizen. He spoke to the Nobel committee by phone from Italy on Tuesday. 'It was a great surprise and I obviously didn't expect it,' he said, according to NPR. The BBC reported he told a news conference: 'I have to emphasise how lucky I was. Because when we started this project, everybody realised this was maybe a good idea, but very few thought it would work, including myself.'

The IceCube Neutrino Observatory is a research facility at the South Pole in Antarctica, NPR reported, with the University of Wisconsin–Madison as its lead institution. The BBC reported it is made up of thousands of light sensors on long cables drilled and frozen into a 1km cubic block of ice. Most neutrinos pass straight through the ice, but occasionally one interacts with it, producing charged particles that give off a blue glow, according to the BBC. The pattern and timing of that light let scientists estimate where the neutrino came from, the BBC reported.

Neutrinos are elusive subatomic particles, the BBC reported, and NPR described them as tiny cosmic particles with a very small mass. The BBC reported the Sun produces vast numbers of them, with billions passing harmlessly through an area the size of a fingernail every second, while NPR reported trillions zip through human bodies every second. IceCube searches for much higher-energy neutrinos produced by violent processes far beyond the Solar System, in distant galaxies, the BBC reported. Because neutrinos have no electric charge, magnetic fields do not bend their paths through space, the BBC reported.

Mark Pearce, chair of the Nobel Committee for Physics, said: 'Francis Halzen has led an international team of researchers and engineers who have provided us with a fantastic instrument. His tenacity and scientific vision has paved the way for a new kind of astronomy.' Halzen's research into capturing neutrinos at the South Pole dates back to the 1980s, NPR reported, and he first presented his vision for detecting them there in 1988, the BBC reported. The prize money this year is 12 million Swedish kronor, about $1.2 million, NPR reported.