The Nobel Prize in Physics is awarded to a pioneering scientist in observing “ghostly” cosmic particles

The 2026 Nobel Prize in Physics was awarded to Francis Halzen, a pioneering Belgian astrophysicist whose work in developing a massive observatory in Antarctica to detect “ghostly” cosmic particles laid the foundations for “an entirely new kind of astronomy.” These tiny, high-energy particles coming from space, known as neutrinos, transmit information that allows scientists to better understand distant galaxies and exploding stars, explained Eva Olsson, a member of the Nobel Committee, during the award ceremony on Tuesday at the Royal Swedish Academy of Sciences in Stockholm.

"Francis Halzen led an international team of researchers and engineers, providing us with a remarkable scientific instrument. His perseverance and scientific vision paved the way for a new kind of astronomy," Nobel Committee Chairman Mark Pierce said in a statement.

Halzen, 82, said during a Nobel press conference via telephone from Italy that winning the prize was a "huge surprise" and "a source of happiness." He added: “When we started this project, everyone knew it might be a good idea, but very few thought it would work, including me personally.

“So it was like an adventure where success was not guaranteed.” The professor, who works at the University of Wisconsin-Madison, first presented plans for the IceCube neutrino observatory in 1988, envisioning a massive network of sensors inside the Antarctic ice capable of picking up neutrinos.

The observatory takes advantage of a basic property of neutrinos, which is that they produce a flash of light when they collide with an atomic nucleus, and sensors installed inside pure, frozen ice can detect that flash. Neutrinos arrive at Earth from deep within the universe, and are often called “ghostly” because they are so elusive or nearly imperceptible, they can pass through almost any type of matter without being changed.

It is almost massless, and does not carry an electrical charge. They can also cross the most extreme environments, such as stars, planets and even entire galaxies, while remaining unchanged.

“It's been a while since the Nobel Prize was awarded to just one person, and this speaks to the uniqueness of his vision,” said Richard Fitzgerald, editor-in-chief of the American Institute of Physics' journal Physics Today. “It took a team of hundreds of people to build the observatory, but it all started with one person's idea.”

Inside the Ice Observatory While billions of neutrinos originate from the Sun, neutrinos coming from other regions of space are much rarer and difficult to detect. In the 1980s, Halzen first realized that the ice of Antarctica might be an ideal environment for capturing these hidden neutrinos, but installing sensitive equipment deep in the ice was a massive undertaking, requiring researchers to drill holes kilometers deep and lower strings of light sensors into them.

The previous IceCube project, known as AMANDA, was completed in 2000, but did not succeed in detecting the high-energy neutrinos that Halzen was looking for, according to the Nobel Committee. Then work began on the “IceCube” project, which is a cubic kilometer of ice equipped with optical sensors, and reached its full size in 2011, when it included 5,160 optical sensors distributed over 86 cables.

In 2013, the research team announced the first evidence supporting the detection of cosmic neutrinos, and nearly two years later they had collected enough data to confirm their discovery. The Nobel Committee said that “IceCube” will take neutrino astronomy to a new level, providing information about cosmic phenomena obscured by dust clouds and distant space objects such as black holes.

A project is planned to expand the "IceCube", allowing it to monitor 8 cubic kilometers of ice. Last year, the Physics Prize went to John Clarke, Michel Devoret and John Martinez for their discovery of a phenomenon known as quantum mechanical tunneling within an electrical circuit, an advance that laid the foundation for quantum computing and other related technologies.

The prize money is 12 million Swedish krona, or about $1.2 million. On Monday, the Nobel Prize in Medicine was awarded to three scientists in recognition of their work in developing a technology that helps decipher the inner mechanisms of the brain.

The awards announcement continues on Wednesday with the announcement of the Chemistry Prize, followed by the Literature Prize on Thursday. As for the Peace Prize, it will be announced on Friday, then the awards will conclude with the announcement of the Nobel Memorial Prize in Economic Sciences on October 12.