2. It’s All Greek to Me! Disrupting Reality- The Cosmology of the Ancient Greeks

3. Greek View of the World

4. c. 900-800 B.C.HOMER n Iliad and Odyssey n Summaries of legends for which the constellations are named.

5. The World of Homer n The “world” surrounded by an ocean, enclosed in a celestial sphere n Quotation #1

6. c. 624 -547 B.C. THALES of MILETUS n Rational inquiry leads to knowledge n Early cosmology n Water the fundamental element n Earth circle or cylindrical disk floating on water. n All motions circular n First to predict solar eclipse

7. c. 611-546 B.C. ANAXIMANDER n Founder of Astronomy? n Wrote comprehensive history of Universe n Universal medium n Earth a cylinder suspended in space n “Hoops of Anaximander”-tubular rings of fire n Quotation #2

8. c.570-500 B.C. PYTHAGORAS of SAMOS nMnMathematical/ Mystical brotherhood nRnReality is mathematical in nature “All is number” nEnEarth is a sphere at the center of the universe, all celestial motions are circular.

9. Students of Pythagoras n PHILOLAUS c.500-400 B.C. n Revealed secrets of the brotherhood n Earth moves around central fire n Quotation #3 n ANAXAGORAS n Moon reflects sunlight n Sun a red hot stone n Universe created in a huge vortex in the primordial chaos (Q #4) n Persecuted for impiety n Milky Way (Q #5)

10. c. 428-347 B.C. PLATO n Material world an imperfect representation of ideal creation n Learn by reason, not observation n The Academy: “Let none who has not learned geometry enter here.”

11. Students of Plato n EUDOXUS c.408-356 B.C. n First mathematical cosmology n 27 spheres to account for motions of all known heavenly bodies n Quotation #6 n ARISTOTLE c.384-322 B.C. n First to adopt Physical Laws-four elements plus quintessence n Spherical Earth n Eudoxus’s system REAL, not device. n The Lyceum

12. c. 310-230 B.C. ARISTARCHUS n Relative sizes and distances of earth, sun, moon n First to propose that Earth orbits sun n Objections: –Moving Earth –Lack of observable stellar parallax

13. c. 273-? B.C. ERATOSTHENES n Accurately measured the size of the earth

14. Two More Important Men... n APPOLONIUS c.265-190 B.C. n Eccentric orbit for sun to account for apparent change in speed of sun over course of year n Epicycle to account for retrograde motion n HIPPARCHUS c.190-120 B.C. n 1080 stars catalogued n amazing quantity of observational data