1. The Earth’s Tilt

2. The Earth is tilted on its axis at 23.5 degrees The Earth is tilted on its axis at 23.5 degrees For 6 months the Northern Hemisphere is tilted towards the sun and for the next 6 months the Southern Hemisphere is tilted towards the sun For 6 months the Northern Hemisphere is tilted towards the sun and for the next 6 months the Southern Hemisphere is tilted towards the sun This is the cause for the seasons This is the cause for the seasons

3. Solstices/Equinox Summer Solstice-June 22nd, Maximum amount of daylight for the Northern Hemisphere Summer Solstice-June 22nd, Maximum amount of daylight for the Northern Hemisphere Autumnal Equinox-September 22 st, Equal amount of sunlight for both Hemispheres Autumnal Equinox-September 22 st, Equal amount of sunlight for both Hemispheres Winter Solstice-December 22 st, Maximum amount of daylight for the Southern Hemisphere Winter Solstice-December 22 st, Maximum amount of daylight for the Southern Hemisphere Vernal Equinox-March 22 st, Equal amount of sunlight for both Hemispheres Vernal Equinox-March 22 st, Equal amount of sunlight for both Hemispheres

5. Precession Precession is the change in the orientation of a rotating axis Precession is the change in the orientation of a rotating axis The angle remains constant but the direction of the axis changes The angle remains constant but the direction of the axis changes Would not affect Earth’s Seasons but would affect what stars are seen at night Would not affect Earth’s Seasons but would affect what stars are seen at night

6. Nutation Nutation is the wobbling that occurs around Earth’s axis which changes the angle about ½ of a degree every 18 years Nutation is the wobbling that occurs around Earth’s axis which changes the angle about ½ of a degree every 18 years Happens due to the gravitational pull of the moon Happens due to the gravitational pull of the moon

7. Barycenter A barycenter is the center that 2 objects orbit around. A barycenter is the center that 2 objects orbit around. When the moon orbits a planet both bodies orbit around a point in the middle When the moon orbits a planet both bodies orbit around a point in the middle This point is closer to the larger body This point is closer to the larger body

8. Barycenter The sun does not remain motionless in the solar system. The sun does not remain motionless in the solar system. Due to the pull of the planet’s gravity the sun orbits a barycenter in the solar system Due to the pull of the planet’s gravity the sun orbits a barycenter in the solar system