Cause of Curvature (2/2)

• Curvature is coupled directly to mass, not to q.
  
  
• Any curvature of spacetime without a force
  is caused by change in the potential which are coupled to both mass and electric charge.
  
  
• General relativity provides a way to calculate curvature by comparing two nearby geodesics
  using a tidal effect. Because general relativity lacks a means within the geodesic
  to calculate the cause of curvature, general relativity is incomplete.