Francis Halzen wins the 2026 Nobel Prize in Physics solely: leading the Antarctic "IceCube" project, opening a new era of neutrino astronomy.

Belgian-born American physicist Francis Halzen 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. This award marks a fundamental shift in humanity's approach to exploring the extreme environments of the universe. On Tuesday, October 6, the Nobel Committee announced in its latest bulletin that this year's Physics Prize would be awarded in full to Halzen alone, recognizing his scientific vision and leadership in building a one-cubic-kilometer neutrino detector in the Antarctic ice. Since its completion in 2011, the device has successfully captured high-energy neutrinos from outside the solar system, confirming the existence of natural particle accelerators in the universe far more powerful than any on Earthby a factor of a million. Mark Pearce, chair of the Nobel Committee for Physics, said Halzen's tenacity and scientific foresight "paved the way for an entirely new kind of astronomy." The significance of this discovery lies in the fact that high-energy neutrinos barely interact with any matter and can travel in a straight line from extreme environments in the distant universe without being deflected or losing energy, thus carrying cosmic information that no other particle or photon can convey. This provides astronomers with an observation window that was previously completely closed. From a vision to a "telescope" beneath the Antarctic ice Halzen's core insight was born in 1988: Antarctica's transparent ice is not an obstacle but a natural neutrino detection medium. When a neutrino collides with an atomic nucleus, it produces a faint flash of light, and optical sensors embedded in the ice can capture this signal, thereby tracing the neutrino's origin and energy. Antarctic ice offers several unique advantages: high purity, few sources of interference, stable geological structure, and no seismic activity, making it an ideal detection environment. The concept quickly won support from scientific peers, and early tests of sensors in the ice were carried out in the following years. Halzen has long been affiliated with the University of WisconsinMadison, where he is now the Gregory Breit Distinguished Professor and a Vilas Research Professor, while also serving as principal investigator of the IceCube Neutrino Observatory. He received his master's degree from KU Leuven in Belgium in 1966, earned his doctorate in 1969, and joined the University of Wisconsin in 1972, devoting himself to this line of research for decades thereafter. One cubic kilometer of ice, a window into the extreme universe High-energy cosmic neutrinos are extremely rare, and detecting enough collision events requires an enormous volume of detection mediumthis is the fundamental reason IceCube is so large. The device covers a full cubic kilometer of Antarctic ice and, after years of construction, was officially completed in 2011. Shortly after completion, the research team discovered the first high-energy neutrinos and published results in the years that followed, confirming that these neutrinos must originate from outside the solar system. This discovery marked the formal and comprehensive launch of the search for cosmic neutrino sources. Scientists have long known that natural particle accelerators exist in the universe with energies reaching a million times the level of Earth-based laboratories, but what these sources actually are, where they are located, and how they operate internally remain largely unresolved mysteries. Unlike photons, high-energy neutrinos are unaffected by dust, gas, and magnetic fields during their long cosmic journeys and can faithfully preserve information about their place of origin, making them a key probe for answering these questions. A detector still running, with future potential yet to be unlocked IceCube continues to collect neutrino interaction data to this day. The Nobel Committee noted that these data will help researchers gain a deeper understanding of the violent cosmic environments in which high-energy neutrinos are produced, and may even reveal previously unknown cosmic phenomena. In the award announcement, Mark Pearce commented that Halzen led an international research and engineering team and provided the scientific community with "an extraordinarily remarkable instrument," and that his academic tenacity and scientific foresight are of milestone significance. Halzen's research spans multiple fields, including particle physics, astrophysics, cosmology, and neutrino astronomy. He transformed a concept that seemed bold and remote in 1988 into a scientifically operating device over more than two decades, and ultimately rewrote humanity's understanding of the universe's extreme environments through its detection results. This article is reprinted from "Wallstreetcn," author: Zhao Ying; GMTEight editor: Liu Jiayin.