-
240 BCE
Eratosthenes
first accurate measurement of earth's circumference -
126
ptolemy
ptolematic thory -
1543
Nicholas Copernicus
Nicholas proposed heliocentric theory -
Feb 13, 1578
Tycho Brahe
Tycho Brahe first sketches of "Tychonic system" -
Period: to
Johannes Kepler
improved the heliocentric theory of Nicolaus Copernicus, explaining how the planets' speeds varied -
Sir Isaac Newton
law of gravitation -
Albert Einstein
Photoelectrical effect