Wuming Luo

A giant sphere filled with liquid flashes when an elusive particle, a neutrino, flies through it. Inside the sphere, like fireflies on a Christmas tree, hang thousands of tubes that catch these flashes. To pinpoint exactly where the flash occurred and how much energy arrived, you need to know the position of each tube to within a millimeter.

A huge pool of clear liquid is hidden deep underground. Inside, there is nothing but a pristine 'broth' that flashes with faint light when an invisible particle flies through. This is the JUNO detector—20,000 tons of liquid scintillator built to hunt for neutrinos. The main enemy of such a hunt is not darkness but its own noise.