1. Sun-Moon-Earth System
Ch. 28 Sec. 3
Sun-Moon-Earth System

2. Daily Motions Sun gives us warmth and energy
Moon rises our oceans and illuminates our sky
Ancient calendars are based on moon and sun phases

3. Annual Motions Days and weather vary through out the year
Annual changes from orbit around the sun
Ecliptic: plane in which the earth orbits the sun

4. Earth’s Tilt Tilted at 23.5 degrees Axis tilt remains same all year
This shows how the sun changes altitude in the sky
Season are based on the tilt

5. Solstices Summer Solstice Sun overhead the Tropic of Cancer
Around June 21 or 22 of each year
Sun does not set in Arctic circle

6. Solstices Winter Sun directly over the Tropic of Capricorn
Occurs on Dec. 21 or 22
Sun never rises in the Arctic Circle

7. Equinoxes
Both have equal sunlight
Vernal and Autumnal

8. Phase of the Moon Light is from the reflection of the sun
As moon moves along it’s orbit, the amount of light we see increase
Dark Moon positioned between earth and sun is New moon

9. Phase of the Moon
Waxing: light that we can see is on the right side of the moon starts to increase
Crescent – Less that half light is showing
Gibbous – More than half light is showing
Half of the moon is light: 1st quarter

10. Phase of the Moon Full moon: entire side is light: Full moon
Waning: Light starts to decrease on the left side of the moon
Half the moon is light: 3rd quarter

11. Motions of the Moon
Time between full moons is known as the Lunar Month
About 29.5 days
Rises and sets 50 minutes later each day b/c moon moved 13o in orbit over 24 hr period

12. Tides
Moon pulls up on the ocean and slingshots the water on the opposite side to create bulges
Every 12 hrs the ocean level rises and falls

13. Solar Eclipse Moon passes between sun and earth
Shadow in the inner/ darker portion is called the Umbra
Outer/lighter shadow is the Penumbra

14. Effects of orbits
Due to the difference in orbit keeps us from have an eclipse every month.
Closest point that moon and earth are is Perigee
Appears larger
Farthest point is the Apogee
Appears smaller

15. Lunar Eclipse
Moon passes through earths Shadow