General relativity dissolved the idea of space as an empty stage

Rovelli explains that before Einstein, physicists imagined space as a fixed, unchanging backdrop in which objects and forces played out their motions, with gravity acting mysteriously at a distance. Einstein's general relativity replaced this picture entirely: space and time are not a passive container but an active, flexible entity, capable of bending, stretching, and rippling in response to mass and energy. Gravity, in this view, is not a force pulling objects across empty space but the curvature of spacetime itself, shaped by whatever mass occupies it. A planet does not get tugged toward the sun by an invisible string; it simply follows the straightest available path through a spacetime warped by the sun's presence. Rovelli treats this as one of the most beautiful ideas in the history of thought, because it unifies geometry and gravity into a single elegant structure. It also implies that spacetime itself has a history and a dynamism, rather than being a static grid the universe merely occupies. Takeaway: what looks like an invisible force may really be the shape of the space we move through.