PBS
Pbs Learning Media: Galileo: Sun Centered System
In the early 1600s, most people believed that the Sun revolved around a stationary Earth. This video segment adapted from NOVA tells how Galileo proved that the Sun, not Earth, is at the center of our universe.
Rice University
Galileo Project: The Ptolemaic System
This site from The Galileo Project of Rice University provides this discourse on the Ptolemic System that attempted to explain the motion of heavenly bodies. Pictures, charts, and links are all provided for additional information.
Wolfram Research
Wolfram Science World: Ptolemy (Ca. 100 Ca. 170)
A very brief description of Ptolemy's role in researching astronomy. Links to related information.
American Association of Physics Teachers
Com Padre Digital Library: Open Source Physics: Phases of Venus Model
A simulated activity examining the phases of Venus introduced in the Copernican system and derived from the Ptolemaic system.
Famous Scientists
Famous Scientists: Thabit Ibn Qurra
Learn about the life and work of Thabit ibn Qurra, a mathematician, physician, astronomer, and translator of the Islamic Golden Age.
Other
The Ptolemaic Model of the Planetary System
An easy-to-read description and history of Ptolemy's geocentric model of the universe. Geocentric means that Ptolemy believed the Earth was the center of the universe.