Which theory describes gravity as the curvature of spacetime?

• A. Newtonian gravity
• B. Special relativity
• C. General relativity
• D. Quantum gravity

Answer: (C)

Mass and energy bend the fabric of spacetime, and in general relativity gravity is the result of objects following the curved geometry. This means planets move along the curved paths (geodesics) cut into spacetime by the Sun’s mass, and light rays bend when they pass near massive bodies. The same curvature explains why time runs slower in strong gravity and why light is deflected by gravity. This picture goes beyond Newtonian gravity, which treats gravity as a force in flat space, and beyond Special Relativity, which doesn’t include gravity. Quantum gravity is a separate, speculative effort to unite gravity with quantum mechanics. So describing gravity as curvature of spacetime best fits what general relativity says about how the universe works.