Building a telescope more than a kilometer under the ice in Antarctica was a gamble. But Francis Halzen had the audacity to try. Decades later, his visionary work has opened a new era of neutrino astronomy, and won the Belgian-born physicist the 2026 Nobel Prize in Physics. Brian Greene sits down with Halzen to examine the effort to build the IceCube detector at the South Pole and use it to track high energy neutrinos from deep space. Covering the history of the neutrino from its theoretical origins to its confirmation, to the science underlying the IceCube detector, to the challenges of constructing it, the conversation explores a new way for scientists to examine the cosmos. Greene and Halzen discuss the search for dark matter, mapping the galactic plane with neutrinos enabled by machine learning, potential insights into quantum gravity, as well as Halzen’s advice to young scientists: Follow your obsession, because understanding is the real reward. A compelling conversation on disc...