Before the 17th century, people generally believed that Earth was at the center of the universe, a system originally developed by Ptolemy. Galileo, however, was not afraid to challenge existing beliefs when he published...

Galileo used his telescope to gather data about the heavens, and his observations and theories sparked much controversy. This video segment discusses Galileo's observations of sunspots, which challenged the current...

This essay describes the influence that the pendulum had on Galileo's thinking and science. It also discusses the use of a pendulum to measure time. This is a part of The Galileo Project, an extensive web site on the...

Created by the Institute and Museum of the History of Science, the site features virtual exhibits and tours of the IMSS museum. Some of their main exhibits include Galileo's notebooks and a whole section on Leonardo de...

This website gives an account of the people who revolutionized science. There is information on the lives and works of some of the most important figures in the history of astronomy such as Galileo. Kepler, and Newton....