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Apr 5, 1054
Crab supernova explosion
Chinese and American Indian astronomers observe the Crab supernova explosion -
Apr 5, 1100
Lodestone as a Compass
First known written description of the use of lodestone as a compass -
Apr 5, 1512
Heliocentric Theory
Nicholas Copernicus first states his heliocentric theory in Commentariolus -
Apr 5, 1543
De Revolutionibus de Orbium Coelestium
Nicholas Copernicus publishes De Revolutionibus de Orbium Coelestium (On the Revolutions of the Heavenly Spheres) -
Apr 5, 1572
Supernova in Cassiopeia
Tycho Brahe observes the supernova that appears in Cassiopeia -
Apr 5, 1577
Comets are not atmospheric Phenomena
Tycho Brahe uses parallax to prove that comets are distant entities and not atmospheric phenomena -
Objects fall at same speed
Galileo Galilei uses balls rolling on inclined planes to show that different weights fall with the same constant acceleration -
Empirical Laws
Johannes Kepler states his first two empirical laws of planetary motion -
Highly Accurate Pendelum Clock
Christian Huygens builds the first highly accurate pendulum clock -
Law of Gravitational Force
Isaac Newton deduces the inverse-square gravitational force law from the acceleration of the moon -
Calculus
Isaac Newton invents his calculus -
Speed of Light
Ole Romer uses the orbital mechanics of Jupiter's moons to estimate the speed of light -
Wavefont Sources
Christian Huygens states his principle of wavefront sources -
Inverse Square Law
Joseph Priestly proposes an electrical inverse-square law -
Light Can't Escape
John Michell suggests that some objects might be so massive that not even light could escape -
Heat is Energy
Count Rumford has the idea that heat is a form of energy -
Mass of Earth
Henry Cavendish measures the gravitational constant and determines the mass of the Earth -
Electric Battery
Alessandro Volta announces his invention of the electric battery -
Absoluter Zero
Lord Kelvin discovers the absolute zero point of temperature -
Light is an electromagnetic phenomena
James Maxwell states that light is an electromagnetic phenomenon -
Second Law of Thermodynamics
Lord Kelvin formally states the second law of thermodynamics -
Special Relativity
Albert Einstein completes his theory of special relativity -
Discovery of the Neutron
James Chadwick discovers the neutron -
Neutrinos
Wolfgang Pauli proposes the existence of neutrinos to account for an apparent violation of energy conservation in certain nuclear reactions