Part 1: The Equivalence Principle and Curved Spacetime
Einstein realized that gravity is not an invisible pulling force. Massive objects deform the geometry of spacetime, and objects simply travel along the straightest possible paths (geodesics) through that curved geometry.
- Spacetime Fabric (three dimensions of space welded to one dimension of time)
- The Event Horizon (the boundary where escape velocity exceeds the speed of light)
- Gravitational Redshift (light waves climbing out of gravity wells lose energy and stretch)