'Ghost particles' from space telescope wins 2026 Nobel Prize in Physics

Prof Francis Halzen won for "decisive contribution" to developing the IceCube Neutrino Observatory

Belgian-born physicist Prof Francis Halzen has won the Nobel Prize in Physics for his pioneering work on an observatory that detects particles from space, shedding light on the distant universe.

The Royal Swedish Academy of Sciences said "his vision and scientific leadership have been fundamental for the IceCube Neutrino Observatory".

Halzen, who is now a US citizen at the University of Wisconsin–Madison, told a news conference that he was surprised his idea worked so well.

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Neutrinos are elusive subatomic particles. The Sun produces vast numbers of them: every second, billions pass harmlessly through an area the size of your fingernail.

It is composed of thousands of sensors on long cables that are drilled and frozen into a 1km cubic block of ice.

At the observatory, most neutrinos pass straight through the ice, but occasionally one interacts with it, producing particles that give off a telltale flash of light.

"Francis Halzen has led an international team of researchers and engineers who have provided us with a fantastic instrument," said Prof Mark Pearce, Chair of the Nobel Committee for Physics.

This blurry image is of the Milky Way, but it is composed of neutrino particles

On the rare occasions when a neutrino strikes an atomic nucleus, it produces fast-moving charged particles. It is these racing through the ice, which give off a blue glow, which sensitive light detectors can pick up.