Chapter 14: The Motions of Earth, the Sun, and the Moon

14-1: Motions of Earth Revolution movement of a planet or other body around another body All planets revolve around the Sun Earth revolves around the Sun every 365 ¼ days or 1 year

14-1: Motions of Earth Rotation spinning of a planet or other body on its axis Earth rotates west to east Earth rotates on its axis every 24 hours or 1 day

14-1: Motions of Earth Axis imaginary line through the center of a planet or other body around which it spins Earth is tilted 23 ½ ° on its axis

14-2 Time Zones Solar Noon time of day when the sun is highest in the sky There are 24 times zones in the world Each time zone is 15° wide

14-2 Time Zones U.S. has 8 time zones total 4 for the continental U.S. Pacific, Mountain, Central, & Eastern

14-2 Time Zones As you go west, you lose time As you go east, you gain time International Date Line boundary where each new day starts

14-3 Seasons Seasons are caused by Tilt of the Earth Movement around the Sun Angle which the Sun’s rays strike Earth’s surface

14-3 Seasons Summer = tilted towards Sun; more direct rays Winter = tilted away from Sun; more indirect rays Winter in N. Hemisphere = Summer in S. Hemisphere

14.4 Solstices & Equinoxes Distance btw Earth & Sun change throughout the year Seasons do not depend on distance from Sun

14.4 Solstices & Equinoxes Perihelion closest point to Sun (happens in January) Earth is 147 million km from Sun aphelion farthest point to Sun (happens in July) Earth is 152 million km from Sun

14.4 Solstices & Equinoxes Solstice the beginning of summer and winter 1 Pole has 24 hours of daylight, the other Pole has 24 hours of darkness Summer Solstice is on or about June 21; N. Pole light, S. Pole dark Winter Solstice is on or about December 21; N. Pole dark, S. Pole light

14.4 Solstices & Equinoxes Equinox the Sun is directly over the equator at solar noon; the beginning of spring & fall 12 hrs. of light/12 hrs. of dark Vernal (spring) equinox is around March 21 Autumnal (fall) equinox is around September 21

14-5 Motion of moon Moon revolves around Earth every 27 1/3 days Moon revolves @ 3,500 km/hr Moon rotates on its axis every 27 1/3 days

14-5 Motion of moon Apogee moon farthest from Earth Perigee moon closest to Earth

14-5 Motion of moon When Earth, Moon, Sun line up in their orbits & all 3 gravities are working together = really high tides and really low tides. This is a Spring Tide. Happens twice a month

14-5 Motion of moon When Moon & Sun at right angles & gravities working against each other = no high or low tides. This is a Neap Tide. Happens twice a month

14-5 Motion of moon Moon appears to rise in east and set in west Moon comes into view at moonrise 50 minutes later each day

14-6 Phases of the Moon Moon appears to change shape because of the way it reflects light from the Sun Phases depend on the position of the Sun, Moon, & Earth Moon takes 29 ½ days to go through all phases

14-6 Phases of the Moon Waxing increasing in light New Moon no light Waxing Crescent1/4 right side lit 1st Quarter right 1/2 lit Waxing Gibbous 3/4 right side lit

14-6 Phases of the Moon Waning decreasing in light Full Moon all light Waning Gibbous 3/4 left side lit 3rd Quarter left 1/2 lit Waning Crescent left 1/4 lit

14-7 Lunar eclipses Umbra center, dark part of a shadow Penumbra outside, lighter part of a shadow

14-7 Lunar eclipses Lunar Eclipse when the moon passes directly through Earth’s shadow Can only occur during a full moon

14-7 Lunar eclipses Total Lunar Eclipse when the moon moves entirely into Earth’s umbra; all sunlight is blocked = moon entirely dark Total lunar eclipse is rare & don’t happen regularly

14-7 Lunar eclipses Partial Lunar Eclipse only part of the moon moves into Earth’s umbra; some sunlight is blocked = part of moon dark

14-8 Solar eclipses Solar Eclipse when the moon passes directly btw Earth & Sun Most of Sun’s surface is blacked out & we see the corona

14-8 Solar eclipses Total Solar Eclipse entire face of Sun blocked by moon seen in small area of world Partial Solar Eclipse only part of the face of the Sun is blocked seen over a larger area