Pythagoras: 'Around 500 B.C., most Greeks believed that the Earth was round, not flat. It was Pythagoras and his pupils who were first to propose a spherical Earth.'
Anaxagoras: 'In 500 to 430 B.C., Anaxagoras further supported Pythagoras' proposal through his observations of the shadows that the Earth cast on the Moon during a lunar eclipse. The shadow reflected was circular.'
Aristotle'sarguments for a spherical Earth
Positions of the North Star
Shape of the Moon and the Sun
Disappearance of ships when they sail over the horizon
North Star
Evidence for a spherical Earth
Shape of the Sun and the Moon
Evidence for a spherical Earth
Disappearing Ships
Evidence for a spherical Earth
Eudoxus' system
Believed the Sun, moon, planets and stars were attached to fixed spheres that revolved around the stationary Earth
Heliocentrism
The astronomical model in which the Earth and planets revolve around the Sun
Geocentrism
Any theory of the structure of the solar system (or the universe) in which Earth is assumed to be at the center of it all
Eratosthenes' method
Observed the angles of the noonday sun in two Egyptian cities to determine the size of the Earth
Hipparchus' achievements
Observed and compared the brightness of 850 stars
Developed a method for predicting the times of lunar eclipses
Measured the length of the year to within minutes of the modern value
Claudius Ptolemy believed the Earth was the center of the universe and proposed a geocentric model with planets moving in a complicated system of circles
