Sylvain Marsat

According to Einstein's theory, massive objects cause spacetime curvature, like a heavy ball warping a rubber sheet. As they accelerate, they create ripples — gravitational waves, akin to the circles from a stone dropped in a pond.

The Universe is not silent: it is filled with a continuous gravitational-wave hum. In a decade, the LISA space observatory will tune its "ears" to the millihertz range, and the richest source will be our Galaxy — tens of thousands of white dwarf pairs whirling in a frantic dance.