Francis Halzen, a professor of physics at the University of Wisconsin–Madison, has been awarded the 2026 Nobel Prize in Physics for his decisive contributions to the IceCube Neutrino Observatory and the discovery of high‑energy neutrinos of astrophysical origin. The prize, worth 12 million Swedish kronor, recognizes his vision dating back to 1988 for using the clear, stable ice at the South Pole as a detector for elusive subatomic particles. [support-1] Halzen was born in 1944 in Tienen, Belgium, and received his PhD in 1969 from KU Leuven before joining the faculty in Madison. [support-1]
This image is from the 2026 Nobel Prize announcement page, relevant to the article about Francis Halzen's Physics prize win for IceCube work.
IceCube consists of a cubic kilometre of Antarctic ice, instrumented with light sensors buried about two kilometres below the surface. When a high‑energy neutrino occasionally collides with an atomic nucleus in the ice, it creates a charged particle that moves faster than the speed of light in ice, producing a flash of Cherenkov radiation that the sensors record. [support-1] Because neutrinos interact with matter only extraordinarily rarely, a detector of this immense volume—roughly one billion tons of ice—is needed to capture enough of these fleeting interactions to make scientific observations possible. [support-1]
The value of neutrinos for astronomy lies in their lack of electrical charge and extremely weak interactions, which means they are not deflected by interstellar magnetic fields and can travel across the universe essentially undisturbed. [primary] This property allows researchers to infer the direction of their cosmic origins, effectively enabling a form of astronomy that uses subatomic particles rather than light to probe energetic processes such as those near black holes. [primary] Although IceCube has detected high‑energy neutrinos that must come from outside the solar system, scientists have not yet been able to pinpoint specific sources with certainty; as of the prize announcement, only about 10 % of the observed neutrinos are known to originate within the Milky Way, while the remainder point to distant, still‑unidentified accelerators. [primary]