1. Tides and Eclipses Read Your Textbook: –Chapter 3 Homework Problems –Review Questions: 1, 2, 5, 8 –Review Problems: 1, 2, 6 –Web Inquiries: 3, 4 (1, 2 in 5 th ed.)

2. Earth and Moon The Moon is … –1/4 the diameter of the Earth –1/100 the mass of the Earth –1/50 the volume of the Earth –60 Earth radii away –Gravitationally locked in a synchronous orbit (the far side is never seen from the earth) To Scale... Earth Moon

3. Same Side View The moon’s rotation equals its revolution period. The same side always faces earth. 50% is always illuminated by the sun.

4. Observational Apparitions Moon Horizon Illusion http://www.GriffithObs.org/IPSMoonIllus.html

5. Observational Apparitions Man on the Moon?

6. Observational Apparitions Lady on the Moon?

7. Observational Apparitions Lady on the Moon?

8. Observational Apparitions Toad on the Moon?

9. Observational Apparitions Toad on the Moon?

10. Observational Apparitions

11. Tidal Forces As the Earth Rotates, we are carried into and out 2 High and 2 Low Tides Every Day

12. Tides (Weak and Strong) Sun’s tidal influence is ~ 1/2 that of the moon Strongest Tides Moon New or Full Weakest Tides Moon 1st or 3rd quarter

13. Other Factors Winds Ocean Currents Coast Line Geometry and Topography Tides are predictable for any given location!

14. Moon’s Orbit Sidereal Month –Orbit –Star reference Synodic Month –Phases –Sun reference

15. Observing From Spaceship Earth horizon

16. Spaceship Earth horizon

17. Spaceship Earth horizon

18. Spaceship Earth horizon

19. Spaceship Earth horizon

20. Earth Rotation Stars setting Stars rising Stars overhead

21. Lunar Phases Lunar location with respect to the sun determines phase seen at the earth.

22. Lunar Phases The 3rd quarter moon rises when? The full moon sets when?

23. Lunar Phases New 0.00 1st Quarter 0.25 Full 0.50 3rd Quarter 0.75 horizon

24. Lunar Phases The 3rd quarter moon rises when? –Rises at Midnight –Sets at Noon The full moon sets when? –Sets at Sunrise (6 am) –Rises at Sunset (6 pm)

25. Observational Geometry horizon

26. Observational Geometry Inner Planets –Mercury –Venus Outer Planets –Mars –Jupiter –Saturn –Uranus –Neptune –Pluto Sun Earth Orbit Inner Planet Outer Planet

27. Conjunctions Inner Planets –Conjunction (Aligned with the Sun) Inferior Sun

28. Conjunction Outer Planets –Conjunction (Aligned with the Sun) Always Superior, Never Inferior Sun

29. Conjunctions Inner Planets –Conjunction (Aligned with the Sun) Inferior Superior Sun

30. Elongation Inner Planets –Conjunction (Aligned with the Sun) Inferior Superior –Greatest Elongation (Farthest From Sun) Eastern Western Sun

31. Elongation Inner Planets –Conjunction (Aligned with the Sun) Inferior Superior –Greatest Elongation (Farthest From Sun) Eastern Western Best Time to View Inner Planet

32. Conjunction Outer Planets –Conjunction Aligned with the Sun Always Superior, Never Inferior Sun

33. Opposition Outer Planets –Conjunction Aligned with the Sun Always Superior, Never Inferior –Opposition Opposite the Sun Earth Closest Approach Best Time to View Outer Planet Sun

34. Eclipse Conditions New or Full Moon Moon at a “NODE” in its orbit.

35. Lunar Eclipse Moon in Earth’s Shadow

36. Eclipses Are Shadows Solar Eclipse Shadow Caught By Weather Satellite Image

37. Solar Eclipse Geometry Total Solar Eclipse Partial Solar Eclipse Annular Solar Eclipse

38. The Saros Cycle The repeating of eclipse geometries known to the ancients: http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros.html The Eclipse Home Page: http://sunearth.gsfc.nasa.gov/eclipse/eclipse.html