History of Gravity

Heliocentricity

Jun 20, 1543

Nicolaus Copernicus states the sun as the center of the Solar System with other bodies revolving around it.

Leaning Tower of Pisa Experiment

Jun 17, 1589

Galileo Galilei drops balls off the Leaning Tower of Pisa with different masses and watches them fall at the same rate.

Laws of Planetary Motion

Jun 1, 1650

Thanks to some new measurements by Tycho Brahe, Johannes Kepler was able to make three claims about planterary motion: 1. The orbit of a planet is an ellipse and the sun is at one of the foci. 2. A line segment from between the sun and planet sweeps out equal areas. 3.The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit. Click Here for more information.

Newton's Laws of Motion and Gravitation

Jun 21, 1687

Newton publishes Principia Mechanica, which proposes that an inverse square force law links to elliptical orbits; in addition, Newton included his Laws of Motion and Gravitation.

Coulomb's Law

Jun 21, 1789

Charles-Augustin de Coulomb finds that an electrostatic attraction relates in full analogy with Newtonian gravity, which led to Coulomb's Law.

n-dimensional Geometry

Jun 21, 1883

Wilhelm Killing works on n-dimensional non-Euclidean geometry and Lie algebras; these concepts eventually construct the Killing vector, which is applied in differential geometry, quantum gauge field theory, supergravity. and string theory.

Mnkowski Spacetime

Jun 21, 1907

Minkowski establishes the idea of a spacetime continuum.

Theory of Relativity

Jun 21, 1907

Albert Einstein establishes his Theory of Relativity, stating that all laws of physics are the same in all inertial frames, and the speed of light is constant in all frames.

Kaluza-Klein Theory

Jun 21, 1921

Theodore Kaluza and Oskar Klein found that electromagnetism could be derived from gravity if a fourth dimension exists.

Heisenberg's Research

Jun 21, 1943

Heisenberg's research sparks some of the items that would eventually become crucial components of string theory

Birth of String Theory

Jun 21, 1970

Theorists: Gabriele Veneziano, Pierre Ramond, Andre Neveu, John Schwarz, Joel Scherk, etc.

Calabi-Yau Conjecture

Jun 21, 1976

Shing-Tung Yau discovers Calabi-Yau space, which is a manifold used in analyzing mirror symetry.

Superstring Theory

Jun 21, 1981

Michael Green and John Schwarz discover that the combination of string theory and supersymmetry yields an excitation spectrum that has equal numbers of fermions and bosons, revealing that string theory can be supersymmetric. The resulting objects are called superstrings.