-
He developes experimental scienific methods in static and dynamics, for determining specific weights. He also generalizes the theory of the centre of gravity and applies it to three-deminsional bodies.
-
He discusses the theory of attraction between masses and states that the heavenly bodies are "accountable to the laws of physics".
-
He publishes The Book of the Balance of Wisdom, in which he invents a hydrostatic balance for measuring specific gravity and proposes that the gravity and gravitational potential energy of a body vary depending on its distance from the centre of the Earth.
-
He places the sun at the gravitational center, starting a revolution in science.
-
He induces the period relationship of a pendulum from observation.
-
He describes a hydrostatic balance for measuring specific gravity.
-
He formulates modified Aristotelean theory of motion based on density rather than the weight of objects.
-
Galileo Galilei conducts experiments on pendulum motion.
-
Galileo Galilei creates a mathematical formula of the law of falling objects based on his earlier experiments.
-
Galileo Galilei discovers the parabolic arc of projectiles through experiment.
-
Ismael Bullialdus suggests an inverse-square gravitational force law.
-
Isaac Newton introduces an invers-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.
-
Isaac Newton proves that planets moving under an inverse-square force law will obey Kepler's laws.
-
Isaac Newton uses a fixed length pendulum with weights of varying composition to test the weak equivalence principle to 1 part in 1000.
-
Henry Cavendish measures the force of gravity between two masses, leading to the first accurate value for the gravitational constant.
-
William Kingdon Clifford suggests that the motion of matter may be due to changes in the geometry of space.
-
Simon Newcomb observes a 43 arcsecond per century excess precession of Mercury's orbit.
-
Henri Poincaré presents the principle of relativity for electromagnetism.
-
Albert Einstein completes his theory of special relativity and states the law of mass-energy conservation. E=mc^2
-
Albert Einstein introduces the principle of equivalence of gravitation and inertia and uses it to predict the gravitational redshift.
-
Albert Einstein completes his theory of general relativity. The new theory perfectly matches Mercury's strange motions.
-
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.
-
Albert Einstein shows that the field equations of general relativity admit wavelike solutions.
-
Arthur Eddington leads a solar eclipse expedition which claims to detect gravitational deflection of light by the sun.
-
Theodor Kaluza demonstrates that a five-dimensional version of Einstein's equations unifies gravitation and electromagnetism.
-
Fritz Zeicky states that galaxies could act as gravitational lenses.
-
Albert Einstein, Leopold Infeld, and Banesh Hoffmann show that the geodesic equations of general relativity can be deduced from its field equations.
-
John Wheeler discusses the breakdown of classical general relativity near singularities and the need for quantum gravity.
-
Robert Pound and Glen Rebka test the gravitational redshift predicted by the equivalence principle to approximately 1%.
-
Irwin Shapiro predicts a gravitational time delay of radiation travel as a test of general relativity.
-
He hypothesizes that the heavenly bodies and celestial spheres are subject to the same laws of physics as Earth. In his Astral Motion and The Force of Attraction, he proposes that there is a force of attraction between heavenly bodies.