Francis Halzen wins Nobel Prize in physics for IceCube neutrino work

IceCube observatory at South Pole detected astrophysical neutrinos

The Royal Swedish Academy of Sciences announced the 2026 Nobel Prize in physics in Stockholm on Tuesday, naming Francis Halzen, 82, a professor at the University of Wisconsin–Madison, for his contributions to the IceCube Neutrino Observatory and his discovery of high-energy neutrinos of astrophysical origin.

“Francis Halzen has led an international team of researchers and engineers who have provided us with a fantastic instrument. His tenacity and scientific vision has paved the way for a new kind of astronomy,” Mark Pearce, chair of the Nobel Committee for Physics, said in a news release.

Halzen, who was born in Belgium, spoke to the committee by phone from Italy on Tuesday. “It was a great surprise and I obviously didn’t expect it,” he said. He added that the award had been predicted, but that the announcement still made him feel “strange.”

The IceCube Neutrino Observatory is a research facility at the South Pole in Antarctica, with the University of Wisconsin–Madison as its lead institution, according to its website. Halzen’s research into capturing neutrinos at the South Pole dates to the 1980s.

Neutrinos are tiny cosmic particles with a small mass. They are produced by stars such as the sun, and trillions pass through the human body every second. Because neutrinos cannot be observed directly in motion, scientists detect them by measuring the flashes of light or charged particles produced when they collide with other bits of matter. Halzen studied a rare group of these particles that scientists consider messengers from the cosmos, offering clues to how the universe evolved.

The 2026 physics prize carries 12 million Swedish kronor (about $1.2 million), whether the award goes to an individual, a small group of laureates or an organization.

This year’s Nobel cycle began Monday with the medicine prize, awarded to three scientists whose work led to a tool that uses light to help unravel how the brain works. The schedule continues Wednesday with the chemistry prize, Thursday with literature, Friday with the peace prize and Monday with the Nobel Memorial Prize in Economic Sciences.

Last year’s physics prize went to three scientists for research on quantum tunneling, a phenomenon in subatomic particles that enabled the ultra-sensitive measurements achieved by MRI machines and laid the groundwork for better cellphones and faster computers.