Francis Halzen wins Nobel physics prize for 'ghostly messengers' from space

Belgian physicist Francis Halzen won the Nobel physics prize on Tuesday for using Antarctic ice to capture high-energy neutrinos from the distant cosmos. The Royal Swedish Academy of Sciences announced the award, saying his work on the IceCube Neutrino Observatory paved the way for a new kind of astronomy.

Why did Francis Halzen win the Nobel physics prize?

Halzen was honored "for decisive contributions to the IceCube Neutrino Observatory and the discovery of high-energy neutrinos of astrophysical origin," the jury said. The observatory is a cubic kilometer of ice fitted with light sensors, which lets researchers capture neutrinos, rare subatomic particles, from extremely energy-rich processes in the distant universe.

What are the 'ghostly messengers' from space?

"This year's prize is about ghostly messengers from space," Ellen Moons, secretary general of the Royal Swedish Academy of Sciences, told a news conference. The messengers are neutrinos, which the academy says reach us without changing direction or losing energy.

"This means they can provide information that is not available in any other way," the academy said in a statement. It explained that cosmic neutrinos with extremely high energies are very rare, so an enormous volume of ice is needed to observe an adequate number of collisions.

How did the IceCube Neutrino Observatory come about?

Halzen first presented his idea for the observatory in 1988, and it quickly gained the support of other researchers. Preliminary testing was conducted a few years later, but the observatory was not completed until 2011. It soon discovered the first "high-energy neutrinos."

"This project, everybody thought, is a cute idea that won't work," Halzen said in an interview with the Nobel Foundation. He said he was thankful the project received support even early on.

Halzen is the first physics laureate since 1992 to receive the prize without sharing it. Erin O'Sullivan, a neutrino astrophysicist at Sweden's Uppsala University and spokeswoman for the IceCube collaboration, said it was "well deserved that he is the sole winner of this prize." "He really was the instigator of this whole project and has seen it through since the very early days," she told AFP.

Who is Francis Halzen, the 2026 Nobel physics laureate?

Halzen, 82, was born in Tienen, Belgium, and is a professor at the University of Wisconsin-Madison in the United States, where he is a citizen. He told the news conference by telephone shortly after the announcement: "It was a great surprise, and I obviously didn't expect it."

"For me, the main pleasure of it, besides winning the Nobel Prize, is that I hope this reflects on the really courageous people who joined me in the beginning of this project," he said.

Belgian Prime Minister Bart De Wever extended his "heartfelt congratulations" to Halzen, noting that he was the 11th Belgian to win a Nobel and the second in physics. "An impressive recognition of a life dedicated to unravelling the greatest secrets of the cosmos through its most minuscule manifestations," De Wever said in a post on X.

Could neutrinos carry messages from aliens?

Asked whether the neutrinos could contain messages from potential distant civilizations, Halzen said it has been speculated that this would be an ideal way to communicate with aliens. "But I don't think I will go there. I think we have enough realistic problems to deal with right now," he said.

Which Nobel prizes are still to be announced in 2026?

The physics award is the second Nobel of the season. The medicine prize went on Monday to US psychiatrist and neurologist Karl Deisseroth and German scientists Peter Hegemann and Georg Nagel for their pioneering work in optogenetics, which involves controlling nerve signals with light.

The chemistry prize follows on Wednesday, and the literature laureate will be revealed on Thursday. The peace prize, perhaps the most keenly anticipated, is due on Friday, and the economics prize wraps up the Nobel season on October 12.

Last year's physics prize went to Briton John Clarke, Frenchman Michel Devoret and American John Martinis for putting quantum mechanics into action. Their work enabled the development of digital technology from cellphones to a new generation of computers.