Motions of Earth Rotation spinning of Earth from

Motions of Earth • Rotation • spinning of Earth from west to east on its own axis (counterclockwise) • results in day and night • Earth makes a complete rotation in 24 hours

Motions of Earth • Revolution • Earth moves around the sun (elliptical) every 365¼ days • Perihelion – Earth is closest to the sun • Aphelion – Earth is farthest from the sun

Motions of Earth • Precession • Change in direction of Earth’s axis, but without any change in tilt (very slow movement)

Motions of Earth • Nutation • Wobbling around the processional axis • Occurs over 18 year period due mainly to the gravitational force of the Moon

Motions of Earth • Barycenter • The point between 2 objects where they balance each other

Motions of Earth • Elliptic • The plane in which a planet orbits about the Sun (star)

Earth’s Seasons • Earth’s axis is tilted 23. 5 o • Label your picture • March 20/21 – Spring Equinox (#4) • June 21/22 – Summer Solstice (#1) • September 21/22/23 – Autumn Equinox (#2) • December 21/22 – Winter Solstice (#3)

Earth-Moon Motions • The moon moves counterclockwise to Earth • Perigee – moon is closest to Earth • Apogee – moon is farthest from Earth • Phases of the moon are the different amounts of light that appears on the moon (see illustration)

Lunar Eclipses • • The Earth is blocking the moon Occurs during full moon phases Penumbra – light is partially blocked by Earth Umbra – light is completely blocked by Earth

Solar Eclipses • The Moon is blocking the Sun. • If the moon is partially blocking the sun, a partial solar eclipse will occur