Deep within the Antarctic ice lies IceCube, an observatory that uses a cubic kilometre of ice to detect neutrinos from the universe. On the rare occasions when a neutrino interacts with matter in the ice, it can produce charged particles. The light emitted by these particles is recorded by the observatory’s sensors.

Neutrinos can travel vast distances without changing direction, carrying information about their sources. They let researchers study some of the most energetic processes in the universe.

Through his vision and scientific leadership, Francis Halzen, professor at the University of Wisconsin–Madison in the United States, has laid the foundations for the observatory and a new form of astronomy.

Swedish contributions to an international collaboration

Researchers at Stockholm University and Uppsala University have contributed to the development and construction of IceCube. Around 1,000 of the observatory’s approximately 5,000 sensors were built and validated in Stockholm and Uppsala. Sweden also developed and manufactured the cables that supply power and communications to the sensors deep in the ice. The Swedish Polar Research Secretariat has supported the work with logistical support and on-site personnel at the South Pole.

IceCube has recently undergone a major upgrade. Following preparations over several field seasons, drilling and installation were completed during the 2025/26 Antarctic summer. The Swedish Polar Research Secretariat had a technician on site at the South Pole during the 2024/25 and 2025/26 seasons.

The upgrade aims to provide more precise measurements of neutrino properties and a better understanding of the Antarctic ice, which may also improve analysis of previously collected data.