General relativity

General relativity is a fundamental theory of gravitation formulated by Albert Einstein, published in 1915. It extends the principles of special relativity and provides a new understanding of gravity, not as a force in the traditional sense, but as the curvature of spacetime caused by mass and energy. Key concepts in general relativity include: 1. **Spacetime**: Instead of treating space and time as separate entities, general relativity combines them into a four-dimensional continuum known as spacetime.