Francis Halzen, raised in Tienen and educated in Leuven, built the strangest telescope on Earth. Today, the Nobel Committee honoured him for it.
On 6 October 2026, the Royal Swedish Academy of Sciences announced that the Nobel Prize in Physics goes to Francis Halzen of the University of Wisconsin-Madison, USA. He is honoured “for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin.”
Behind that formal citation is a very Belgian story: a student from Tienen, a degree from KU Leuven, and a bold idea that took him to the bottom of the world.
A Tienen boy who became an “outstanding student”
Halzen has lived and worked in the United States for many years, but his roots are firmly Flemish. He spent his youth in Tienen, the Flemish Brabant town long known as the “sugar city.” Locals have wasted no time claiming him, and the town has reacted with pride, remembering him as an outstanding student.
Trained in Leuven
His scientific path began at KU Leuven, where he studied physics. He earned his master’s degree in 1966 and his doctorate in 1969. The university was quick to celebrate its alumnus. Rector Severine Vermeire said the prize recognises a scientist who, “through vision, determination, and international collaboration, has broadened our view of the universe.” She added that it makes the Leuven community “particularly proud” that his training started there.
The idea: turn Antarctic ice into a telescope
Halzen’s Nobel-winning idea is simple to state and hard to believe. In 1988, he presented his vision of catching “neutrinos” at the South Pole.
Neutrinos are often called “ghost particles.” They stream through the Earth and through our bodies without us ever noticing. Only very rarely does one hit an atomic nucleus, and when it does, it produces a tiny flash of light.
That flash is what Halzen wanted to catch. The clear, ancient ice of the South Pole is free from many sources of interference, and the region is geologically stable, with no earthquakes. Put light sensors deep in that ice and it can serve as a detector.
IceCube: a cubic kilometre of ice
Cosmic neutrinos with extremely high energies are very rare, so seeing enough of them takes enormous volume. The result is the “IceCube Neutrino Observatory”: a full cubic kilometre of ice, equipped with light sensors and buried nearly 1.6 kilometres (about a mile) below the surface.
IceCube was completed in 2011. Researchers soon detected the first high-energy neutrinos. A few years later, they published their discovery of neutrinos that must come from far outside our solar system.
Why does this matter? Unlike other particles, neutrinos reach us without changing direction or losing energy. They carry information about the universe’s most violent processes that we can get in no other way. The Nobel Committee says Halzen’s work has paved the way for “a new kind of astronomy.”
“I can hardly believe it”
Halzen himself seems just as surprised as everyone else. Speaking by phone link at the Nobel press conference, he called the news “a huge surprise.” He revealed that just the weekend before, at a science festival in Bergamo, Italy, someone had suggested he might win. He says he couldn’t believe it then, and still can’t now.
He was quick to share the credit. He thanked the many scientists and engineers behind IceCube, especially “the courageous people who believed in it from the very beginning.” He is also candid about the early days: “When we started, we didn’t know if it would ever work.” Talent, he says, and “a bit of luck” made the difference.
Belgium reacts
Belgian politicians were just as quick to celebrate. Flemish Minister-President Matthias Diependaele (N-VA) highlighted Halzen’s Flemish roots and the strength of Flemish science: “From Tienen to the South Pole: Francis Halzen is pushing the boundaries of our knowledge.” Federal Foreign Minister Maxime Prévot (Les Engagés) called the award “a remarkable scientific achievement” and said it shows what international cooperation can achieve.
Halzen isn’t the first Belgian Nobel Prize winner. In fact there have been twelve! Time for me to get a new category in my Famous Belgians page!
Over to you!
What do you think of Francis Halzen’s extraordinary journey, from Tienen to the South Pole and ultimately to the Nobel Prize? Had you heard of him before the 2026 Nobel announcement? I’d love to know! Leave a comment below, or drop me an email.
I created Discovering Belgium in 2011 to share the country’s hidden stories, fascinating places, and remarkable people. Through articles, photography, and audio walks, I share discoveries that reveal Belgium beyond the obvious. Hope you enjoy this site.
Definitely a cause for celebration!
Yes there will be a party or two somewhere, I am sure.
Each year, when they announce the Nobel Prizes for Physics (and Chemistry), I never really understand what it’s for.
This year, laypeople like me can at least have a mental image of a telescope under the ice. I still don’t quite understand what they are looking for and why, but I feel slightly less excluded than in other years.