A telescope inside the ice
The 2026 Nobel Prize in Physics has been awarded to Francis Halzen of the University of Wisconsin-Madison "for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin." The Royal Swedish Academy of Sciences announced the prize on 6 October.
IceCube is buried in the clear ice beneath the Amundsen-Scott South Pole Station, where more than 5,000 optical sensors hang on strings through a cubic kilometre of ice. Construction finished in 2011, and two years later the team announced the discovery of high-energy neutrinos from far beyond our solar system.
Messengers from distant sources
Neutrinos are nearly massless particles that pass through matter almost without interacting. Because they are not deflected by magnetic fields and are not absorbed by dust and gas, they can carry information from violent cosmic events that light cannot escape. "It's a way of bringing us information about distant cosmic sources, which we are unable to acquire in other ways," said Mark Pearce, chair of the Nobel Committee for Physics, at the announcement.
Halzen was born in Tienen, Belgium, in 1944 and earned his doctorate at KU Leuven in 1969. He led the effort to build the detector and to persuade funders that a kilometre of Antarctic ice could work as a telescope. The IceCube team now includes more than 400 scientists around the world.
A week of prizes
The physics award closed the scientific half of Nobel week. The medicine prize went to Karl Deisseroth, Peter Hegemann and Georg Nagel for discoveries about light-gated ion channels and optogenetics, a technique that lets researchers switch neurons on and off with light. The chemistry prize went to Henri B. Kagan and Kenso Soai for non-linear effects and autocatalysis in asymmetric organic synthesis, work the committee said has been decisive for chemists who design reactions used to make pharmaceuticals.
The economics prize, announced on 12 October, went to Robert E. Hall and Michael Woodford for their work on the microeconomic foundations of macroeconomic stabilisation. Each prize this year is worth 12 million Swedish kronor.