2. Lecture 2: Spaceship Earth Man is…related inextricably to all reality, known and unknowable…plankton, a shimmering phosphorescence on the sea and the spinning planets and an expanding universe, all bound together by the elastic string of time. It is advisable to look from the tide pool to the stars and then back to the tide pool again. -- John Steinbeck

3. Math stuff to review Powers of Ten and Scientific Notation Converting between different units Metric System Finding Ratios See Appendix C in your textbook

4. Earth’s Rotation

5. The Earth’s Orbit

6. The Reason for Seasons Spring Equinox Fall Equinox Summer Solstice Winter Solstice

8. Summer Solstice at the Arctic Circle

9. Precession of the Earth’s Axis

10. Phases of the Moon

12. Eclipses Solar eclipse: occurs when the Moon’s shadow falls on the Earth – occurs only at new moon. Lunar eclipse: occurs when the Moon passes through the Earth’s shadow – occurs only at full moon.

14. Solar Eclipses Total Partial Annular path

15. A total eclipse of the Sun

17. Fixed Stars and Wandering Planets

18. The Sun’s Motion Through the Zodiac

19. The Mystery of Retrograde Motion Jupiter, shown at one month intervals

21. Explaining Retrograde Motion

22. Stellar Parallax

23. Stellar Motions in the Solar Neighborhood

24. Rotation in the Galaxy

25. Hubble’s Law

26. The Expanding Universe

27. Astronomical Distance Units Astronomical Unit (AU) 150 million km distances between planets parsec (pc)3.09E13 km distances between stars kilo-parsec (kpc)1000 pc sizes of galaxies Mega-parsec (Mpc)1.0E6 pc distances between galaxies 1 parsec = 3.26 light years