Motions Within Motions Or, why you always feel like you are just going in circles. Stars: Rise in the east, set in the west. On a yearly cycle. The stars that are visible at night changes. Sun: Rises in the east, sets in the west. On a yearly cycle the following occur: length of day changes, seasons, “height” of the sun at noon, and which stars are visible at night. There are also occasional eclipses. Moon: Rises in the east, sets in the west and this coincides with the tides. Goes through phases on a near monthly basis. Full moon seems to bring out werewolves and odd behavior. There are also occasional eclipses. Planets: Rise in the east, set in the west. Pass through constellations on their own schedule. Occasionally reverse direction for short periods. Change in brightness and exhibit phases.

Sheer Lunacy Rises in the east, sets in the west on a 24 hour 50 minute cycle. Tides on Earth also have a 24 hour 50 minute cycle. Goes through phases on a 29.5 day cycle. The spring and neap tides on Earth have a 29.5 day cycle. The same side of the moon always faces Earth (Synchronous Orbit). Eclipses occur on a very complex schedule with lunar eclipses being more common than solar eclipses.

The Moon revolves around the Earth. Sidreal Month It is how long it takes the Moon to pass through a 360º orbit. It is 27.3 days. Synodic Month It is how long it takes the Moon to return to the same phase. It is 29.5 days. http://bcs.whfreeman.com/dtu6e/pages/bcs-main.asp?i=02090.05&v=category&ns=0 Animation of the two types of months. The Moon reflects the light of the Sun. The Moon reflects 7% of incident light. The Earth reflects 37% of incident light. Phases result from the Moon revolving around the Earth and reflecting the light of the Sun. The phase of the Moon is the portion of the Moon facing the Sun that can be seen from Earth. Hence which phase is seen depends on the current Sun-Earth-Moon configuration. For a new moon the lit portion of the moon is the far side of the Moon. For a full moon the lit portion of the moon is the side facing the Earth.

Only half of the Moon is ever visible from Earth. The phase of the Moon is the portion of the Moon facing the Sun that can be seen from Earth. New Moon: None of the visible Moon is bright. Crescent Moon: Less than half of the visible Moon is bright. Quarter Moon: Half of the visible Moon is bright. (The term quarter comes from what part of the cycle it is in.) Gibbous Moon: More than half of the visible Moon is bright. Full Moon: The entire visible Moon is bright. Only half of the Moon is ever visible from Earth. The Moon is a sphere. Only half of the moon is ever lit by the sun. The Moon is still a sphere. Hence which phase is seen depends on the current Sun-Earth-Moon configuration. For a new moon the lit half of the Moon is the half of the Moon not facing the Earth. For a full moon the lit half of the Moon is the half of the Moon facing the Earth. http://bcs.whfreeman.com/dtu6e/pages/bcs-main.asp?i=02090.04&v=category&ns=0 Animation of Sun-Earth-Moon Configuration causing phases.

Diagram of Sun-Earth-Moon causing lunar phases from page 12 of your text.

Time of Day and Phases of the Moon New Moon Time: Noon Moon is directly overhead Time: 6:00am Moon is rising Time: Midnight Moon is not visible New Moon Earth Sunlight Time: 6:00pm Moon is setting

Time of Day and Phases of the Moon First Quarter Moon Time: 6:00am Moon is not visible Time: Noon Moon is rising Time: Midnight Moon is setting Earth Sunlight Time: 6:00pm Moon is directly overhead First Quarter Moon

Time of Day and Phases of the Moon Full Moon Time: 6:00am Moon is setting Time: Midnight Moon is directly overhead Time: Noon Moon is not visible Full Moon Earth Sunlight Time: 6:00pm Moon is rising

Time of Day and Phases of the Moon Full Moon Time: 6:00am Moon is directly overhead Third Quarter Moon Time: Noon Moon is setting Time: Midnight Moon is rising Earth Sunlight Time: 6:00pm Moon is not visible

Naming the Moon Blue Moon: Definition One: The second of two full moons in a single month. It is uncommon since the cycle of phases of the moon is 29.5 days (synodic month) which is almost a month. Definition Two: The third of four full moons occurring in a season. Again this is uncommon since the cycle of phases of the moon is 29.5 days and seasons are ~91 days (365/4=91.25). (Found this out from Zoom Astronomy at Enchanted Learning: http://www.enchantedlearning.com/subjects/astronomy/moon/Phases.shtml Another writer challenges both of these definitions as being created after the phrase “Once in a Blue Moon” and suggests some other possibilities. I think this sounds well considered. http://www.rog.nmm.ac.uk/leaflets/blue/blue.html Harvest Moon: The full moon that occurs closest to the autumnal equinox. The time change of the rising of moon from one night to the next is less than at other times of the year (the reason is complex and addressed by Larry Gedney at http://www.gi.alaska.edu/ScienceForum/ASF7/789.html). This results in the near full gibbous moons and the full moon lighting the fields for harvest for a longer period. The Farmer’s Almanac defines several other names for particular full moons. http://www.farmersalmanac.com/astronomy/moonnames.html An interesting depository of moon facts and explanations is Keith’s moon page: http://home.hiwaay.net/~krcool/Astro/moon/ He even addresses why the moon sometimes appears other colors: http://home.hiwaay.net/~krcool/Astro/moon/moonorange/