The 2026 Nobel Prize in Physics goes to Francis Halzen, a University of Wisconsin–Madison physicist who spent decades pushing an unlikely idea: turning a huge block of Antarctic ice into a telescope for ghostly particles called neutrinos.
The Royal Swedish Academy of Sciences announced the prize on Tuesday, Oct. 6, honoring Halzen “for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin.” He receives the full 12 million Swedish kronor, about $1.2 million.
Why neutrinos are worth the trouble
Neutrinos are tiny, nearly massless particles that pass through almost everything, including the entire Earth, without interacting. That makes them extremely hard to catch. But it is also what makes them valuable: as Halzen’s work showed, they reach us without changing direction or losing energy, so they point straight back to the violent cosmic events that produced them.
Light and charged particles from deep space can be blocked or bent along the way. Neutrinos carry information that other kinds of telescopes can’t get.
A telescope made of ice
Halzen first presented his vision for the detector in 1988, and he helped launch AMANDA, a smaller prototype at the South Pole that showed the approach could work. IceCube itself was completed in December 2010 after seven Antarctic summers of construction.
- Size: one cubic kilometer of ice, a block about 0.6 mile on each side.
- Sensors: 5,160 light detectors hung on 86 cables in holes drilled 1,450 to 2,450 meters (about 4,760 to 8,040 feet) deep.
- Cost: $279 million, about $242 million of it from the US National Science Foundation.
- Team: more than 40 institutions worldwide, led by UW–Madison, where Halzen is principal investigator.
On the rare occasions when a neutrino collides with the ice, the sensors pick up the faint light the collision produces.
What IceCube found
In 2013, IceCube reported the first observation of a diffuse flux of high-energy neutrinos from space. In 2017 and 2018, a campaign that combined IceCube with other telescopes pinned neutrinos to a distant galaxy known as a blazar, TXS 0506+056, the first convincing identification of a high-energy neutrino source. Later results linked about 80 neutrinos to the active galaxy NGC 1068 (2022) and detected neutrinos from our own Milky Way (2023).
“His tenacity and scientific vision has paved the way for a new kind of astronomy,” said Mark Pearce, chair of the Nobel Committee for Physics.
Who is Francis Halzen?
Halzen was born in 1944 in Tienen, Belgium, and earned his PhD from KU Leuven in 1969. He is a theoretical physicist at UW–Madison and was elected to the National Academy of Sciences in 2024.
He is the second American-based Nobel winner this week, after Stanford’s Karl Deisseroth shared Monday’s prize in medicine. The chemistry prize will be announced Wednesday.
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Sources
- ETV Bharat: Nobel Prize in Physics 2026 awarded to Francis Halzen for contribution to IceCube Neutrino Observatory
- China Daily (Xinhua): Francis Halzen wins 2026 Nobel Prize in Physics
- IceCube Neutrino Observatory: About IceCube
- WIPAC, UW–Madison: Francis Halzen faculty profile
- IceCube Collaboration (arXiv): Highlights from the IceCube Neutrino Observatory
- NobelPrize.org: Press release, Nobel Prize in Physics 2026