WASHINGTON, Oct. 6, 2026 — The 2026 Nobel Prize in physics was awarded to Francis Halzen “for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin.”

“Halzen had the audacious idea that you could turn an enormous volume of naturally occurring Antarctic ice into a telescope for neutrinos,” said AIP CEO Michael Moloney. “He then led the decades-long effort that turned that idea into IceCube, which now provides an extraordinary window on the universe and some of its most distant and energetic phenomena.

“This prize highlights one of the great recurring stories of physics: When we find a fundamentally new way to observe nature, we often discover entirely new questions that we didn’t previously know how to ask.”

Francis Halzen was born in 1944 in Tienen, Belgium. He graduated with a doctorate in physics from KU-Leuven in 1969. For two years he worked as a scientist at CERN, before becoming a professor of physics at the University of Wisconsin-Madison in 1972. In 1984 he was named the Gregory Breit Distinguished Professor of physics, and in 2021 he was named the Vilas Research Professor.

Among his many awards and honors, he has been given the Bruno Rossi Prize by the American Astronomical Society and the Medal for Exceptional Achievement in Research by the American Physical Society. He is also an APS Fellow.

In 1988, Halzen proposed what ultimately became the IceCube Neutrino Observatory, a detector for capturing ghostlike messengers buried 2 kilometers beneath Antarctic ice, opening the world to neutrino astronomy. He has been its principal investigator since 2001.

Neutrinos rarely interact with matter — so rarely that over one billion of them went through your hand as you read this sentence. They travel vast distances in space and through materials without budging, carrying information from high-energy sources in the sky, like black holes and exploding stars. When muon neutrinos, one of the three neutrino “flavors,” do interact with Antarctic ice, they create a track of blue light called Cherenkov radiation. By placing 5,160 light sensors within this ice, IceCube detected 28 high-energy astrophysical neutrinos by 2013 — two years after it began operations.

IceCube is located near the Amundsen-Scott Base in Antartica, operated by the University of Wisconsin-Madison. Construction of IceCube was completed in December 2010, six years after it initially began, costing $279 million in total. In 2011, after years of taking data, IceCube began full operation. In 2019, the U.S. National Science Foundation approved funding to upgrade the IceCube detector, which would add additional strings of enhanced optical modules. The following year, outline plans for an extension to the detector, IceCube-Gen2, were submitted.

“Congratulations to Francis Halzen on receiving the Nobel Prize in physics for his groundbreaking contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin,” said Meredith LeMasurier, chief publishing officer of AIP Publishing. “From the bold idea of using Antarctic ice to detect these elusive particles to the discoveries IceCube has made possible, his work embodies the ambition and curiosity that propel science forward. This recognition celebrates an extraordinary scientific achievement and the enduring drive to push beyond the boundaries of what we know about our universe.”

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