How does general relativity describe gravity differently from quantum theory?

General relativity and quantum theory describe gravity through fundamentally different frameworks, creating a significant challenge in modern physics.1

General Relativity

In general relativity, gravity is not viewed as a force in the traditional sense but as a geometric phenomenon. It describes gravity as the curvature of space-time caused by mass and energy. This approach is highly successful at explaining macroscopic phenomena, such as planetary orbits, the evolution of the universe, and the behavior of black holes.2

Quantum Theory

Conversely, quantum theory treats fundamental forces as arising from the exchange of discrete elementary particles. While this framework successfully explains electromagnetism and the strong and weak nuclear forces, a consistent quantum description of gravity remains elusive. To fit gravity into this model, physicists hypothesize the existence of a massless exchange particle called the graviton, which would have a spin of 2.134

Because these two theories rely on incompatible descriptions of space-time and force, reconciling them into a single "theory of everything" is a primary goal of theoretical physics, with string theory representing a leading, though still unproven, attempt at unification.15