4. Revolution of the Spheres

Joshua Barnes -- Fall 1999

The `revolution' described in this week's lecture is a revolution in human thinking. Copernicus started the revolution by recognizing the Earth as one of several similar planets, but he still used laws of planetary motion different from the laws applicable to motion on Earth. Newton completed the revolution by showing that planetary motion and terrestrial motion obey exactly the same laws. Between these two are Kepler, who wrote down the first correct laws of planetary motion, and Galileo, who found observational evidence for the Copernican system and clarified the nature of motion on Earth.

Topics:

• Kepler's laws
• Galileo's discoveries
• Newton's mechanics
• Universial gravitation

Web Resources:

• Solar System Live

  Interactive model of the Solar System, created by John Walker.

• Retrograde Motion in Heliocentric system

  Interactive simulation of retrograde motion, created by Rob Scharein at UBC.

• Kepler's Laws

  Interactive simulation of Kepler's first and second laws, created by Rob Scharein at UBC.

Further Reading:

• The Sleepwalkers by Arthur Koestler
• Doctor Copernicus by John Banville
• Kepler by John Banville

Homework 4: Planetary Positions, due 9/20.

Quiz 4: Kepler's Laws