HISTORY TIME LINE

QUICK REFERENCE FOR "HISTORY THAT SHAPED OUR HOME" 

 

300 BC; Greek Philosophers Plato and Aristotle models Geocentric Theory with Earth as a Sphere. Aristotle publishes in his book “On the Heavens”.

3rd century BC - Aristarchus of Samos proposes heliocentric model, measures the distance to the Moon and its size

200 BC; Greek Aristarchus of Samos placed Earth and other planets in motion around the central Sun but rejected by Aristotleans.

140 CE; Cladius Ptolemy of Alexandria devised complex system of “epicycles” to account for retrograde (going backwards) motion of the planets. Published his theories in book called “Almagest”

200 CE; Ptolemic System developed by Cladius Ptolemaus. “Alamagest”. Geocentric Theory

1270; Roman Catholic church adopts priest Thomas Aquinas theory of a “God-ordained and man-centered” universe which declared the glory of God.

1453; Guttenberg Printing Press developed

1543; Nicholas Copernicus publishes “On the Revolution of Heavenly Spheres” in his last year of his life which postulates a heliocentric, Sun centered, solar system where Earth and planets are revolving around the Sun. “For who would place this lamp of a very beautiful temple in another or better place than this, wherefrom it can illuminate everything at the same time?”

1580; Tycho Brahe, A Danish Astronomer, claimed the most accurate measurement of planet and stars yet still was uncertain of a heliocentric or geocentric model. Was first to suggest a non-circular orbit of planets.

1582 Gregorian Calendar replaces Julian Calendar by Roman Catholic Church by Pope Gregory.

1583 – Galileo Galilei induces the period relationship of a pendulum from observation (according to later biographer).

1586 - Simon Stevin demonstrates that two objects of different mass accelerate at the same rate when dropped.

1589 – Galileo Galilei describes 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.

1609; Galileo Galilei grinds his own glass and makes telescope. Observes Venus moons going around Venus “proving” the Heliocentrism. Publishes his work in Italian so all laymen can read instead of scholar Roman Latin. Recants at Roman Inquisition and banished to _____.

1609 - Johannes Kepler describes to motion of planets around the Sun, now known as Kepler's laws of planetary motion.

1619; Johannes Kepler, German Astronomer student of Tycho Brahe “proved” Heliocentric theory by identifying planet orbits as elliptical and not circular

1640 – Ismaël 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 Moonand 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

1687; Sir Isaac Newton, English Astronomer and President of the Royal Society of England, stated “Law of Universal Gravitation” which mathematically showed the force that kept the Earth and planets going around the Sun as well as what kept the oceans in and air from flying away. Wrote the book “Principia Mathematica.

1758 Edmund Halley successfully predicted, using Newton equations, the return of a comet last seen

1798 – Henry Cavendish measures the force of gravity between two masses, leading to the first accurate value for the gravitational constant

1822; Congregation of the Holy Office remove heliocentric books from the Vatican banned book list.

1838; Friedrich Bessel measures “Stellar Parrallax” method to measure first distance of star, 61 Cygni.

 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 A. Michelson and Edward W. 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

1899 – Hendrik Antoon Lorentz published Lorentz transformations

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

 in 1915, Albert Einstein (1879 – 1955) published the general theory of relativity, in which gravity is not a force but it is a consequence of the curvature of space-time. 

               The new theory explains 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