Francis Halzen wins Nobel Prize in Physics for discovery of cosmic neutrinos

Francis Halzen won the Nobel Prize in Physics on Tuesday, October 6, for his contributions to the IceCube Neutrino Observatory and his discovery of high-energy neutrinos of astrophysical origin.

"Francis Halzen has led an international team of researchers and engineers who have provided us with a fantastic instrument. His tenacity and scientific vision has paved the way for a new kind of astronomy," said Mark Pearce, chair of the Nobel Committee for Physics, in a news release.

Halzen spoke to the committee by phone from Italy after the announcement. "It was a great surprise and I obviously didn't expect it," he said, adding that although it had been predicted before that he would win the prize, the announcement still made him feel "strange." Born in Belgium, the 82-year-old scientist is affiliated with the University of Wisconsin–Madison in the US. Efforts by The Associated Press to reach him directly were not immediately successful.

The IceCube Neutrino Observatory, a research facility located at the South Pole in Antarctica, is led by the University of Wisconsin–Madison. Halzen's research into capturing neutrinos at the South Pole dates back to the 1980s.

Neutrinos are tiny cosmic particles with an extremely small mass, yet they are everywhere: they stream from stars like the sun, and trillions pass through the human body every second. Scientists cannot observe these particles directly. Instead, they measure what happens when neutrinos collide with other matter, producing flashes of light or charged particles. Halzen studied a rare category of neutrinos considered messengers from the cosmos, offering clues to how the universe evolved.

The Royal Swedish Academy of Sciences announced the award in Stockholm. This year's prize money stands at 12 million Swedish kronor, about USD 1.2 million, whether awarded to an individual, a small group of laureates, or an organisation.

Last year, three scientists won the Physics prize for research on quantum tunnelling, work that enabled the ultra-sensitive measurements used in MRI machines and laid the groundwork for better cellphones and faster computers.

This year's Nobel announcements began Monday with the Medicine prize, awarded to three scientists for developing a light-based tool to study how the brain works. The announcements continue Wednesday with Chemistry and Thursday with Literature, followed by the Peace Prize on Friday and the Nobel Memorial Prize in Economic Sciences next Monday.