Min Li

Light can be combed like hair. Instead of hair, we have frequencies; instead of a comb, a laser. The result is a comb made of thousands of even 'teeth'—frequencies. Such an optical comb helps study molecules and measure time with precision down to quadrillionths of a second. An ordinary comb has teeth spaced evenly apart.

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.