Gravitational waves are ripples in spacetime curvature that imperceptibly stretch and squeeze everything around. But the Moon, like a bell, catches these waves: as a gravitational wave passes through it, it makes our satellite vibrate. A new model, for the first time accounting for the real irregularities of the lunar surface, revealed something surprising: where the crust is thicker, vibrations are amplified up to ten times. The reason is akin to a bell of complex shape: the main wave transfers energy into extra motions, and in thick-crust regions the trembling becomes much sharper. This effect turns the Moon into an ideal platform for supersensitive sensors. Earth-based observatories suffer from local noise, while the lifeless Moon offers cosmic silence. Such a detector will hear what's now beyond our reach: echoes of the Big Bang, collisions of black holes and neutron stars. And the biggest surprise: the Moon rings on its own — from faint moonquakes its crust hums for hours, because the dry interior barely dampens the shaking. But through this ringing, one day the quietest echo will emerge — the whisper of the newborn universe.
The Moon 'rings' not only from gravitational waves: even mild moonquakes can trigger vibrations lasting hours, because there's no water to dampen them.