Metric Theories of Gravitation

Metric theories were developed in the 1950s, 1960s, and 1970s in the context of space exploration, experiments with radio waves, quantum technology and high-precision astronomical observations of highly energetic objects such as quasars. These were classified by Clifford Will in his book Theory and Experiment in Gravitational Physics (1993). The tables on page 117 and the cookbook in chapter 5 are sources for this lattice. These theories consider some extra fields, functions and arbitrary parameters, and changes in the universal gravitation constant G.