Gravity waves

Professor Susskind demonstrates how Einsteins's equations can be linearized in the approximation of a weak gravitational field. The linearized equation is a wave equation, and the solution to these equations create the theory of gravitational radiation and gravity waves. Gravity waves represent waves in the curvature of spacetime and thus are effectively tidal forces that change over time. Gravity waves propagate at the speed of light. A rotating binary pulsar is the most likely source of detectable gravity waves.

Professor Susskind closes the final lecture of the course by developing the Einstein-Hilbert action for general relativity, and discussing how minimizing this action leads to the Einstein field equations.