1. 22.2 The Earth-Moon-Sun System Pages 622-627

2. I. Motions of Earth A. Rotation (Spinning) 1. Causes: Day and Night 1. Causes: Day and Night 2. 24 hours- Solar Day 2. 24 hours- Solar Day Sidereal Day 1. Complete rotation with respect to a star other than our sun 2. Time it takes for the other star to appear in the same location (23 hours 56 minutes 4 seconds)

3. B. Revolution (Elliptical Orbit) 1. Perihelion- Closest to sun- Jan 3 rd 2. Aphelion-Farthest from sun- July 4 th

4. C. Precession: Slight movement of Earth’s axis over a period of 26,000 years F. Precession 1. Wobble of a top 2. Now- Points toward Polaris (North Star) 3. 13,000 years- Vega 4. Affects Climate

5. E. Earth’s Axis and Seasons 1. Ecliptic: Apparent annual path of the sun against the backdrop of the celestial sphere 2. Plane of Ecliptic: Imaginary plane that connects Earths’ orbit with the celestial sphere 3. Celestial Equator: Projection of Earth’s equator onto the sky

6. 4. Spring Equinox and Autumn Equinox: Plot sun on celestial sphere over a year- path intersects equator at two points 5. Summer Solstice: Sun appears 23.5 degrees north of celestial equator 6. Winter Solstice: Sun appears 23.5 degrees south of celestial equator

7. The Ecliptic

8. G. Earth-Sun Motion 1. The solar system speeds toward Vega 2. Sun revolves around the Milky Way Galaxy (230 million years) 3. Milky Way Galaxy is approaching the Andromeda Galaxy

9. Precession

10. II. Motions of the Earth-Moon System A. Perigee: moon is closest B. Apogee: moon is farthest C. Phases: Caused by how much of the moon is lit by the sun D. Lunar Motions 1. Cycle: 29.5 days (Synodic Month) 2. Sidereal Month: 27 1/3 days- true period 3. Takes two extra days to reach the point between the sun and earth (starting position) that we see 4. Same side of moon always faces the earth www.PHSchool.comwww.PHSchool.com CODE: czp-7222 www.PHSchool.com

11. Phases of the Moon

12. Lunar Motions

13. III. Eclipses A. Solar Eclipse: When the moon moves in a line directly between Earth and the sun, it casts a dark shadow on Earth. B. Lunar Eclipse: Moon passes through the Earth Shadow. C. During a new-moon or full-moon phase, the moon’s orbit must cross the plane of the ecliptic for an eclipse to take place.

14. Solar Eclipse

15. Lunar Eclipse