1. History of Astronomy  Motions of the sky caused by and controlled by gods. Big Horn Medicine Wheel Temple at Caracol

2. Greek Astronomy - 600 BC  Science - “to learn”  Thales - the world is logical/understandable.  Stars are “balls of fire.”  Predicted solar eclipse.

3. Pythagoreans  Math is the language of music; language of science  Perfect triangle - divine number.  Pythagorean Theorem  Round earth & moon

4. Classical Greece - 450-300 BC  Socrates (470-399 BC)  Plato (430-350 BC)  Aristotle (384-322 BC)  Alexander the Great  Democritus Aristotl e

5. Helenistic Era:350 BC - 400 AD  Alexandria - intellectual hub of the world.  Aristarchus  (310-230 BC) - earth orbits the sun

6. Erastosthenes  Circumference of Earth (276-200 BC)

7. Ptolemy - Geocentric Universe  127-145 AD  Deferents & Epicycles  Retrograde Motion  Almagest - “Greatest of All Books”

8. Geocentric Universe  Earth at center  Spheres for each planet (Mercury, Venus, Mars, Jupiter & Saturn); Moon, Sun, Zodiac constellations, stars.

9. Retrograde Motion

10. Hipparchus (190-120 BC)  Catalog stars  Calculate lunar month  Precession of equinoxes

11. Europe - The Dark Ages Calendars didn’t work! Mercury and Venus were different. Occam’s Razor Calendars didn’t work! Mercury and Venus were different. Occam’s Razor

12. The Copernican Revolution  Nicolas Copernicus  1473 - 1543; Poland  Canon in church; Calendar reform  Heliocentric model  “On Revolutions”  Nicolas Copernicus  1473 - 1543; Poland  Canon in church; Calendar reform  Heliocentric model  “On Revolutions”

13. Explanations of Retrograde Motion Ptolemaic Copernican Epicycles & Deferents Inner Planets move faster Ptolemaic Copernican Epicycles & Deferents Inner Planets move faster

14. Tycho Brahe (1546 - 1601)  Great naked-eye observer  Supernova of 1572  Comet - outside of atmosphere  Uraniborg observatory  Prague & Kepler  Great naked-eye observer  Supernova of 1572  Comet - outside of atmosphere  Uraniborg observatory  Prague & Kepler

15. My Tycho

16. Johannes Kepler (1571 - 1630)  Tycho’s assistant - 1600  Determine the orbit of Mars  Astrology  Three Laws of Planetary Motion  Tycho’s assistant - 1600  Determine the orbit of Mars  Astrology  Three Laws of Planetary Motion

17. 1 st Law of Planetary Motion  The orbits of planets are ellipses with the sun at one focus. 1.Semi-major axis - Astronomical Unit 2.Eccentricity; e = c/a  The orbits of planets are ellipses with the sun at one focus. 1.Semi-major axis - Astronomical Unit 2.Eccentricity; e = c/a

18. 2 nd Law of Planetary Motion  Planets travel faster at perihelion, slower at aphelion; but sweep out equal areas of space in equal amounts of time.

19. 3 rd Law of Planetary Motion  The square of a planet’s orbital period is proportional to its semi-major axis cubed. k = P 2 /R 3  Period is in Earth years  Radius is in AU  k = 1 P 2 = R 3  The square of a planet’s orbital period is proportional to its semi-major axis cubed. k = P 2 /R 3  Period is in Earth years  Radius is in AU  k = 1 P 2 = R 3

20. Galileo Galilei (1564 - 1642)  1609 - Telescope 1.Venus 2.Sun 3.Moon 4.Jupiter 5.Saturn  1610 - Published  1632 “Dialogue Concerning the Two Chief World Systems”  House Arrest

21. Telescope; diagrams of planets

22. Sunspots; Jupiter’s Moons

24. Isaac Newton (1642 - 1727)  Born Christmas Day  Cambridge; closed for plague  Age 23-24; 18 mos. invented calculus  Optics  Laws of Motion, Law of Universal Gravitation  Explained Kepler’s Laws  “Principia”

25. Newton’s Laws of Motion First Law: Every body continues in a state of rest or in a state of motion in a straight line unless it is compelled to change that state by a force acting on it. Second Law: When a force F acts on a body of mass m, it produces and acceleration a equal to the force divided by the mass.Thus, a=F/m, or F=ma. Third Law; To every action there is an equal and opposite reaction.

26. Gravitation Every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of the masses of the particles and inversely proportional to the square of the distance between them.