His head-snapping insight was that gravity could be defined as the curvature of spacetime, and thus it could be represented by a metric tensor.
Einstein's groundbreaking realization was that gravity is not merely a force but a consequence of the curvature of spacetime itself. This perspective revolutionized our understanding of gravitational interactions, moving beyond Newtonian physics and opening up new avenues for exploration in the field of physics.
By expressing gravity in terms of a metric tensor, Einstein provided a mathematical framework capable of describing how massive objects influence the geometry of the universe. This insight fundamentally changed the way scientists approach the study of cosmology and the behavior of celestial bodies.
