Belgian-American particle physicist Francis Halzen won the 2026 Nobel Prize in Physics for creating an observatory at the South Pole to detect high-energy neutrinos. On October 6, the Royal Swedish Academy of Sciences announced the award, citing his “decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin.”
The prize recognizes a scientific project built around a hard-to-detect particle and a vast Antarctic instrument. IceCube sits near the Amundsen-Scott South Pole Station, in a cubic kilometre of pristine ice stretching 2,500 metres below the surface. Each day, it registers about one high-energy neutrino.
A detector in Antarctic ice
Halzen first presented his idea for capturing neutrinos at the South Pole in 1988. The project reached completion in 2011. He realized the ice there could track particles that pass through Earth and human bodies without a trace, interacting with matter only extremely rarely. People sometimes call neutrinos “ghost particles.”
They’re nearly massless and electrically neutral. Even the strongest magnetic fields can’t deflect them. Unlike electromagnetic waves such as visible light, a neutrino’s direction of arrival points directly back to its source. IceCube’s location and scale allow researchers to register rare interactions and investigate where the particles came from.
The Academy said interactions inside IceCube provide information about how high-energy neutrinos form and may uncover previously unknown phenomena. Researchers have determined that the neutrinos come from both within and far beyond our galaxy. They hope to trace them to exploding stars, gamma-ray bursts and cataclysmic phenomena involving black holes and neutron stars.
What the researchers say
“The messengers bring information from the cosmos,” Eva Olsson, of the Royal Swedish Academy of Sciences, said at a press conference. “They open the door to distant galaxies and tell us about the processes of exploding stars.”
Halzen, a professor at the University of Wisconsin–Madison in the United States, said he felt lucky the project worked. “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,” he told the press conference by telephone.
He said the main fruits of his discoveries still lay ahead, and it’s too early to say exactly what the method could reveal about the universe. “The real excitement is that I cannot answer that question yet,” he said. “This is just an introduction to the science, the astronomy is still to come.”
The prize and ceremony
The Royal Swedish Academy of Sciences selects the physics prize, which carries 12 million Swedish crowns ($1.2 million), shared among winners if there are several. Physics held a prominent place in Alfred Nobel’s will. The Swedish inventor and entrepreneur built part of his fortune on inventing dynamite; the prizes began in 1901 and recognize achievements in science, literature and peace. Sweden's central bank later added the economics award.
Past physics laureates include Albert Einstein, Marie and Pierre Curie, Max Planck and Niels Bohr. The previous year's prize went to U.S.-based scientists John Clarke, Michel Devoret and John Martinis for experiments that demonstrated quantum physics in action, research seen as helping advance the next generation of computing and other digital technologies.
The award was the second Nobel announced that year, after Monday's medicine prize announcement. The chemistry prize was scheduled for Wednesday. Sweden's King Carl XVI Gustaf presents Nobel medals at a Stockholm ceremony on December 10, the anniversary of Alfred Nobel's death. A banquet at Stockholm City Hall follows. The peace prize, the only Nobel not presented in Sweden, goes to its recipient separately in Oslo.