Huan Yang

When two black holes merge, the newborn hole rings like a bell, emitting gravitational waves. In the past, only the fundamental tone of this ringing was captured. But analysis of the GW250114 merger showed that the signal hides extra faint vibrations — nonlinear overtones.

At night on a volcano summit, six telescopes stare at the same speck of light. Each catches its own copy of the wave, and if you combine their signals, you get an image that no single instrument could produce alone. But there's a catch: light captured by different stations cannot simply be added like photographs.