Francis Halzen wins Nobel physics prize for Antarctic ‘ghost particle’ hunt

STOCKHOLM, Sweden – The Belgian-American scientist Francis Halzen won the 2026 Nobel Prize in Physics for his work creating an Antarctic observatory of ice to detect high-energy neutrinos, elusive subatomic particles that can reveal otherwise inaccessible information about the cosmos.

Halzen, 82, realized that pristine ice at the South Pole could be used to track such neutrinos, sometimes known as “ghost particles” for the way they pass through the Earth without a trace, only interacting with matter extremely rarely.

“The messengers bring information from the cosmos,” Eva Olsson, of the Royal Swedish Academy of Sciences, told a press conference. “They open the door to distant galaxies and tell us about the processes of exploding stars.”

“It’s a great relief for me because this was not totally unexpected, and around this time of the year I always felt miserable because I didn’t win the prize and thought it was terrible for my collaborators who deserved it so much,” Halzen said at a press conference. “So that problem is finally solved.”

Halzen hailed for detecting ‘messengers from the cosmos’

The interactions registered by the IceCube Neutrino Observatory provide information about how high-energy particles are created and may even reveal previously unknown phenomena, the Academy said.

“We could catch them in ice, that was the goal,” Halzen said of the years-long effort to construct the observatory, which he described as opening “a window on the universe.”

In 2014, the US-based Smithsonian magazine dubbed Halzen “Neutrino Man” when giving him one of its Ingenuity Awards, acclaiming him for an “amazing experiment (that) heralds the beginning of a new era in astronomy”.

It even published a comic illustrating his life: “How One Physicist’s Pursuit of the Cosmos Took Off in Antarctica”.

The observatory – in effect a telescope that shows neutrinos instead of light – is set in a cubic kilometre of Antarctic ice, which extends to a depth of 2,500 metres below the surface near the Amundsen-Scott South Pole Station.

More than 5,000 sensors await blips from the nearly massless high-energy neutrinos, which unlike other particles do not lose energy or change direction, in the hope of tracing their paths back to exploding stars, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars. They can expect to register about one per day.

Halzen, a professor at the University of Wisconsin–Madison in the US, first presented his idea in 1988 for capturing neutrino traces at the South Pole, but the project was not completed until 2011.

“I have to emphasise how lucky I was because, when we started this project, everybody realised this was maybe a good idea, but very few thought it would work, including myself,” Halzen told the press conference by telephone.

Neutrinos are electrically neutral, undisturbed by any magnetic field, which means that, in contrast to electromagnetic waves such as visible light, the direction from which they arrive points directly back to their source.

Fruits of Halzen’s research yet to come

The observatory has determined that high-energy neutrinos originate within but also far outside our own Milky Way galaxy, setting in motion an interstellar quest to find the objects and processes that create them.

Through the long winter at the South Pole, when bringing anything in or out is difficult as temperatures below minus 50 degrees Celsius (minus 58 Fahrenheit) preclude even aircraft landing, a skeleton crew of “winterovers” has to maintain the observatory.

The station, home to many other activities, can house as many as 150 people and has an industrial kitchen, dining room, gym and even a greenhouse. Last week it celebrated the sun’s return above the horizon after six months of night with a six-hole ice-golf tournament.

An extension, IceCube-Gen2, encompassing 8 cubic kilometres of ice, is planned to become operational in 2033 and will be able to detect 10 times as many neutrinos, including much weaker ones.

Halzen said the main fruits of his work were yet to be seen and that it was too early to say exactly what it could reveal about the universe.

“This is a new way of looking at the universe, and it will take bigger telescopes, many more telescopes, to become real astronomy,” he said. “And what this will bring is impossible to predict.”

Winners from Einstein to Bohr and the Curies

Belgian Prime Minister Bart De Wever congratulated Halzen on the recognition of “a life dedicated to unraveling the greatest secrets of the cosmos through its most minuscule manifestations.”

The physics laureate receives an award of 12 million Swedish crowns ($1.2 million). Past winners include several other neutrino research pioneers, for instance Japan’s Takaaki Kajita and Arthur McDonald from Canada in 2015.

The Nobel Prizes were established under the will of Swedish inventor and entrepreneur Alfred Nobel, whose fortune was built in part on the invention of dynamite.

Physics was prominent in Nobel’s will and the prize remains one of the discipline’s highest distinctions. Over the decades, it has recognised discoveries that have fundamentally reshaped humanity’s understanding of the universe.

Among past laureates are some of the most celebrated figures in science, including Albert Einstein, Marie and Pierre Curie, Max Planck and Niels Bohr, whose work helped establish the foundations of modern physics.

The prize is presented in Stockholm on December 10, the anniversary of Nobel’s death. – Rappler.com

($1 = 10.0329 Swedish crowns)