Francis Halzen Wins 2026 Nobel Prize in Physics for South Pole Neutrino Detector
Belgian-born physicist Francis Halzen won the 2026 Nobel Prize in Physics for leading IceCube, a South Pole observatory that catches high-energy neutrinos from space.
Physicist Francis Halzen has won the 2026 Nobel Prize in Physics for his contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin. The announcement came Tuesday in Stockholm.
What IceCube does
Neutrinos are subatomic particles that are electrically neutral and rarely interact with other matter. That is why they are often called "ghost particles." The Sun produces vast numbers of them. According to the BBC, billions pass harmlessly through an area the size of a fingernail every second.
IceCube looks for something rarer: much higher-energy neutrinos produced by violent processes far beyond our Solar System, such as in distant galaxies. These particles act as messengers that point back to those events.
The observatory uses thousands of light sensors buried about 2 kilometres under the Antarctic ice, in deep holes drilled with hot water. Most neutrinos pass straight through. Occasionally one interacts with the ice and produces particles that give off a telltale flash of light. Scientists can use those flashes to trace the neutrino's path back toward its origin.
Halzen's long project
Halzen proposed using the Antarctic ice as a neutrino detector in 1988, and his research into capturing neutrinos at the South Pole dates to the 1980s. New Scientist notes that a detector 1 cubic kilometre in size would catch about one neutrino per day.
He led an international collaboration of more than 450 people from 58 institutions in 14 countries. IceCube was completed in 2011, and the first neutrinos were detected two years later.
Mark Pearce, chair of the Nobel Committee for Physics, said Halzen "has led an international team of researchers and engineers who have provided us with a fantastic instrument." He added that Halzen's "tenacity and scientific vision has paved the way for a new kind of astronomy." The Royal Swedish Academy of Sciences said his vision and scientific leadership were fundamental for IceCube.
Reaction
Speaking to the press conference by phone, Halzen said the news "was a great surprise and I didn't expect it." He called it "a great pleasure." The Associated Press said its early attempts to reach him were not immediately successful.
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What happens next
The Nobel announcements continue this week, with the chemistry prize due Wednesday. Last year's physics prize went to three scientists for work on quantum tunneling. The prize recognizes an instrument that opens a new way to observe the universe, including places ordinary telescopes cannot easily see.
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