Located 700 meters underground near the city of Jiangmen in southern China, a giant sphere—35 meters in diameter and filled with more than 20,000 tons of liquid—has just started a mission that will last for decades. This is Juno, the Jiangmen Underground Neutrino Observatory, a new, large-scale experiment studying some of the most mysterious and elusive particles known to science.
Neutrinos are the most abundant particles in the universe with mass. They are fundamental particles, meaning they don’t break down into smaller constituent parts, which makes them very small and very light. They also