A massive subterranean laboratory, the Jiangmen Underground Neutrino Observatory (JUNO), has opened more than 700 meters beneath a granite hill in Kaiping City, Guangdong Province. Construction of the facility took nine years and cost $300 million.
JUNO’s main objective is to study neutrinos, elementary particles that originated during the Big Bang. These “ghost particles” barely interact with matter, with trillions passing through the human body every second.
The detector is a gigantic sphere filled with a special liquid that emits light upon the rare collisions of neutrinos with other particles. The sphere is protected by an acrylic layer and a cylinder containing 45,000 tons of ultra-pure water. The instrument is expected to record about 50 light flashes daily, mostly from particles originating from two nearby nuclear power plants.
The scientists’ primary goal is to determine the neutrino mass hierarchy, finding out which form of these particles is the heaviest and which is the lightest. To obtain reliable data, at least 100,000 flashes must be registered.
According to project leader Wang Yifang from the Chinese Academy of Sciences, these studies will help create more accurate models of particle physics and cosmology. International experts note that JUNO’s work could be a major step toward understanding how the Universe evolved and why matter, rather than antimatter, predominates in it.
Similar projects are currently underway in other countries: Hyper-Kamiokande in Japan and the Deep Underground Neutrino Experiment (DUNE) in the US, both expected to launch between 2027 and 2031. Their data will either confirm or refine the results found by the Chinese scientists.
