Chronology of Gravitational Physics and Relativity

1640	Ismael Bullialdus suggests an inverse-square gravitational force law.
1665	Isaac Newton deduces the inverse-square gravitational force law from the "falling'' of the Moon.
1684	Isaac Newton proves that planets moving under an inverse-square force law will obey Kepler's laws.
1686	Isaac Newton uses a fixed length pendulum with weights of varying composition to test the weak equivalence principle to 1 part in 1000.
1798	Henry Cavendish measures the gravitational constant.
1845	Urbain Leverrier observes a 35'' per century excess precession of Mercury's orbit.
1876	William Clifford suggests that the motion of matter may be due to changes in the geometry of space.
1882	Simon Newcomb observes a 43'' per century excess precession of Mercury's orbit.
1887	Albert Michelson and Edward Morley do not detect the ether drift.
1889	Roland von Eotvos uses a torsion fiber balance to test the weak equivalence principle to 1 part in one billion.
1893	Ernst Mach states Mach's principle; first constructive attack on the idea of Newtonian absolute space.
1905	Albert Einstein completes his theory of special relativity and states the law of mass-energy conservation.
1907	Albert Einstein introduces the principle of equivalence of gravitation and inertia and uses it to predict the gravitational redshift,
1915	Albert Einstein completes his theory of general relativity.
1916	Albert Einstein shows that the field equations of general relativity admit wavelike solutions.
1918	J. Lense and Hans Thirring find the gravitomagnetic precession of gyroscopes in the equations of general relativity.
1919	Arthur Eddington leads a solar eclipse expedition which claims to detect gravitational deflection of light by the Sun.
1921	T. Kaluza demonstrates that a five-dimensional version of Einstein's equations unifies gravitation and electromagnetism.
1937	Fritz Zwicky states that galaxies could act as gravitational lenses.
1937	Albert Einstein, Leopold Infeld, and Banesh Hoffman show that the geodesic equations of general relativity can be deduced from its field equations.
1957	John Wheeler discusses the breakdown of classical general relativity near singularities and the need for quantum gravity.
1960	Robert Pound and Glen Rebka test the gravitational redshift predicted by the equivalence principle to approximately 1%.
1962	Robert Dicke, Peter Roll, and R. Krotkov use a torsion fiber balance to test the weak equivalence principle to 2 parts in 100 billion.
1964	Irwin Shapiro predicts a gravitational time delay of radiation travel as a test of general relativity.
1965	Joseph Weber puts the first Weber bar gravitational wave detector into operation.
1968	Irwin Shapiro presents the first detection of the Shapiro delay.
1968	Kenneth Nordtvedt studies a possible violation of the weak equivalence principle for self-gravitating bodies and proposes a new test of the weak equivalence principle based on observing the relative motion of the Earth and Moon in the Sun's gravitational field.
1976	Robert Vessot and Martin Levine use a hydrogen maser clock on a Scout D rocket to test the gravitational redshift predicted by the equivalence principle to approximately 0.007%.
1979	Dennis Walsh, Robert Carswell, and Ray Weymann discover the gravitationally lensed quasar Q0957+561.
1982	Joseph Taylor and Joel Weisberg show that the rate of energy loss from the binary pulsar PSR1913+16 agrees with that predicted by the general relativistic quadrupole formula to within 5%.