Timeline of gravitational physics and relativity

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Timeline of gravitational physics and general relativity

1583 - Galileo Galilei induces the period relationship of a pendulum from observation (according to later biographer).
1589 - Galileo Galilei invents a hydrostatic balance for measuring specific gravity.
1590 - Galileo Galilei formulates modified Aristotelean theory of motion (later retracted) based on density rather than weight of objects.
1602 - Galileo Galilei conducts experiments on pendulum motion.
1604 - Galileo Galilei conducts experiments with inclined planes and induces the law of falling objects.
1607 - Galileo Galilei arrives a mathematical formulation of the law of falling objects based on his earlier experiments.
1608 - Galileo Galilei discovers the parabolic arc of projectiles through experiment.
1640 - Ismael Bullialdus suggests an inverse-square gravitational force law.
1665 - Isaac Newton introduces an inverse-square universal law of gravitation uniting terrestrial and celestial theories of motion and uses it to predict the orbit of the Moon and the parabolic arc of projectiles.
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 force of gravity between two masses, leading to the first accurate value for the gravitational constant
1846 - Urbain Le Verrier and John Couch Adams, studying Uranus orbit, independently prove that another, farther planet must exist. Neptune was found at the predicted moment and position.
1855 - Le Verrier observes a 35 arcsecond per century excess precession of Mercury's orbit and attributes it to another planet, inside Mercury's orbit. The planet was never found. See Vulcan.
1876 - William Kingdon Clifford suggests that the motion of matter may be due to changes in the geometry of space
1882 - Simon Newcomb observes a 43 arcsecond per century excess precession of Mercury's orbit
1887 - Albert Michelson and Edward Morley in their experiment do not detect the ether drift
1889 - Loránd Eötvös uses a torsion 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
1898 - Henri Poincaré states that simultaneity is relative
1904 - Henri Poincaré presents the principle of relativity for electromagnetism
1905 - Albert Einstein completes his theory of special relativity and states the law of mass-energy conservation: E=mc²
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. The new theory perfectly matches Mercury's strange motions that baffled Urbain Le Verrier.
1915 - Karl Schwarzschild publishes the Schwarzschild metric about a month after Einstein published his general theory of relativity. This was the first solution to the Einstein field equations other than the trivial flat space solution.
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 - Theodor 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 Hoffmann 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%
1976 - Gravity Probe A experiment confirmed slowing the flow of time caused by gravity matching the predicted effects to an accuracy of about 70 parts per million.
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 PSR B1913+16 agrees with that predicted by the general relativistic quadrupole formula to within 5%
2007 - End of Gravity Probe B experiment.