The 2026 Nobel Prize in Physics has been awarded to Belgian astrophysicist Francis Halzen for pioneering the detection of high-energy neutrinos from deep space, the Royal Swedish Academy of Sciences announced in Stockholm on Tuesday.
Halzen, a professor at the University of Wisconsin–Madison, was honoured for his decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin. Announcing the prize, Nobel committee chair Mark Pearce said Halzen had led an international team of researchers and engineers, and that his tenacity and scientific vision had "paved the way for a new kind of astronomy."
From a 1988 idea to a kilometre-scale detector
Halzen first proposed using the Antarctic ice as a neutrino detector in 1988, and then spearheaded an international collaboration of more than 450 people from 58 institutions across 14 countries to turn that idea into reality. Thousands of light sensors were frozen into deep holes drilled about two kilometres beneath the South Pole ice. When a rare neutrino strikes an atomic nucleus in the ice, it produces a faint blue flash of Cherenkov radiation, and the sensor grid lets scientists trace the particle back to its cosmic origin. Construction was completed in 2011, and the first high-energy cosmic neutrinos were detected two years later.
Why neutrinos matter
Neutrinos are subatomic particles with almost no mass and no electric charge that pass through matter almost undisturbed. More than a billion solar neutrinos stream through every human hand each second, unnoticed. The far rarer high-energy neutrinos caught by IceCube carry information from the universe's most violent environments, including exploding stars and active galaxies, earning them the nickname "ghost-like messengers from the cosmos."
The observatory has gone on to make landmark discoveries. In 2017, IceCube traced a single high-energy neutrino back to a blazar known as TXS 0506+056, the first definitive identification of the source of such a particle. In 2023, it identified neutrinos originating from within our own galaxy, the Milky Way.
Reacting by phone from Italy, Halzen said the win was a "great surprise" and a pleasure. He described the decades-long effort as an adventure in which success was never guaranteed, and said he hoped the prize would also reflect the work of the collaborators who built the project in its early days.
Sources:
- CNN: Nobel Prize in physics awarded to Francis Halzen for his work detecting 'ghostly' cosmic particles
- New Scientist: Nobel prize in physics awarded for discovery of high-energy neutrinos
Halzen, a professor at the University of Wisconsin–Madison, was honoured for his decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin. Announcing the prize, Nobel committee chair Mark Pearce said Halzen had led an international team of researchers and engineers, and that his tenacity and scientific vision had "paved the way for a new kind of astronomy."
From a 1988 idea to a kilometre-scale detector
Halzen first proposed using the Antarctic ice as a neutrino detector in 1988, and then spearheaded an international collaboration of more than 450 people from 58 institutions across 14 countries to turn that idea into reality. Thousands of light sensors were frozen into deep holes drilled about two kilometres beneath the South Pole ice. When a rare neutrino strikes an atomic nucleus in the ice, it produces a faint blue flash of Cherenkov radiation, and the sensor grid lets scientists trace the particle back to its cosmic origin. Construction was completed in 2011, and the first high-energy cosmic neutrinos were detected two years later.
Why neutrinos matter
Neutrinos are subatomic particles with almost no mass and no electric charge that pass through matter almost undisturbed. More than a billion solar neutrinos stream through every human hand each second, unnoticed. The far rarer high-energy neutrinos caught by IceCube carry information from the universe's most violent environments, including exploding stars and active galaxies, earning them the nickname "ghost-like messengers from the cosmos."
The observatory has gone on to make landmark discoveries. In 2017, IceCube traced a single high-energy neutrino back to a blazar known as TXS 0506+056, the first definitive identification of the source of such a particle. In 2023, it identified neutrinos originating from within our own galaxy, the Milky Way.
Reacting by phone from Italy, Halzen said the win was a "great surprise" and a pleasure. He described the decades-long effort as an adventure in which success was never guaranteed, and said he hoped the prize would also reflect the work of the collaborators who built the project in its early days.
Sources:
- CNN: Nobel Prize in physics awarded to Francis Halzen for his work detecting 'ghostly' cosmic particles
- New Scientist: Nobel prize in physics awarded for discovery of high-energy neutrinos
