Simon Campanello: Not even the laureate himself knows what his discovery will lead to

Why does Francis Halzen get the award?

It all starts with an idea he had in the 1980s, he thought he knew how to capture the shy but energetic neutrinos that are ejected from distant places in the universe. Halzen's daring idea was to build an observatory deep in the South Pole's ice cap. Where it is so free from external disturbances that it is possible to capture the light effects from neutrinos colliding with atomic nuclei in the ice. It took over 30 years from idea to completed observatory, but in 2011 Halzen's vision was finally realized, and just a few years later Icecube observed its first high-energy neutrino originating far outside our own solar system.

Why are neutrinos so exciting?

"I have done something terrible," said the Austrian Wolfgang Pauli when he presented his theory of the neutrino in 1931. He believed that it should be impossible to prove the existence of such a volatile particle, and bet a case of champagne that no one would succeed. It wasn't so bad, in the 1950s the neutrino was proven in an experiment and since then neutrino-related research has been awarded no less than five Nobel Prizes. These so-called ghost particles barely interact with their surroundings and continue to fascinate the scientific world with their strange properties. The high-energy particles that Icecube is looking for were actually so shocking when they were discovered in 1991 that they are commonly called Oh-my-god particles.

What can you actually "see" with Icecube?

That is the big question! It is hoped that the observatory can help us understand how some neutrinos can become so terribly energetic, one theory is that supermassive black holes act as a kind of incredibly powerful particle accelerators. But that's just the tip of the iceberg, the truth is we don't know what we can learn from Icecube (and other neutrino observatories). As Francis Halzen himself put it, we have opened a new window to space, and that usually means new, unexpected discoveries.

What role has Sweden played in Icecube?

When Francis Halzen was called during the press conference at the Royal Academy of Sciences, he was careful to thank everyone who helped make Icecube a reality, not least the Swedish researchers and universities that were deeply involved in the project. Two of the key people have been the now deceased professor Per Olof Hult at Stockholm University, and Olga Botner, professor at Uppsala University, who was spokesperson for the observatory during 2013–2017. So even if there is no Swedish prize winner, we can all take some credit for this year's physics prize.