Neutrinos are tiny particles that pass through almost everything. Trillions stream through your body every second without leaving a trace. They are electrically neutral and interact so weakly with matter that catching one is extraordinarily hard.

That elusiveness is also their power. Neutrinos travel across the universe without being bent by magnetic fields, so they point straight back to the violent events that made them, like black holes devouring matter.

Francis Halzen’s idea was to turn Antarctic ice into a detector. IceCube uses 5,160 light sensors spread through a cubic kilometre of ice at the South Pole. On the rare occasions a neutrino interacts, it produces a tiny flash of light.

In 2013, IceCube reported 28 such events, the first solid evidence of high-energy cosmic neutrinos. Later work traced neutrinos to active galaxies and to our own Milky Way.

The 2026 Nobel Prize recognises this new way of observing the universe. With an upgrade adding 600 sensors, neutrino astronomy is just getting started.