1. The Heliocentric Theory

2. Background: Geocentric Theory Geocentric Theory: that the earth is the center of the solar system (and universe) Geocentric theory reflected both the prevailing world view, and desire to explain world mathematically Heavenly bodies inhabited spheres encapsulating the earth, with God and angels outside (Circles/spheres were considered divinely perfect) Epicycles explained anomalous observations of orbits

3. Copernicus (1473-1543, Poland) Heliocentric Theory: that the sun is the center of the solar system Each heavenly body inhabited a sphere encapsulating the sun Simplified the Ptolemaic theory: epicycles still required, but smaller Increased mathematical elegance in accounting for observations justified the theory 1543: On the Revolutions of the Heavenly Spheres

4. Brahe (1546-1601, Denmark) Geocentric theory, but with modifications: sun and moon orbited the earth; remaining planets orbited the sun (Tyco had a pet moose)

5. Johannes Kepler (1571-1630, Germany) Used Brahe’s observational data to support heliocentric theory, but with elliptical orbits 1609: The New Astronomy No answer to problem of why planets orbited elliptically, or why they didn’t hurtle off into space

6. Galileo (1564-1642, Italy) First use of the telescope to study astronomy 1613: Starry Messenger argued for a Copernican interpretation (heliocentric) Fitted close astronomical observation with mathematics; believed in rational, mathematical explanation of physical universe

7. Isaac Newton (1642-1727, England) 1687: published Principia Mathematica: movement through mutual attraction, or gravity Developed calculus, which helped calculate quickly Invented many optical devices, including wide light-gathering telescope Emphasized the importance of empirical data and mathematical relationships

8. Conclusions Heliocentric theory challenged Europeans’ world view –Were humans the most important element of the universe, if they weren’t physically at the center? –Would God create a world for humans that wasn’t at the center? –Was every sentence in the Bible literally true, or was interpretation necessary? Success of the heliocentric theory pointed to the value of –mathematics in describing reality and making predictions based on theory –observational tools to increase humans’ capacity to gather data –man’s ability to explain reality mathematically –math’s ability to simplify complex phenomena so that man can analyze and understand it From Theodore Roosevelt’s history of the war