Presentation on theme: "New 0% Illuminated Waxing Crescent 25% Illuminated on RHS First Quarter 50% Illuminated on RHS Waxing Gibbous 75% Illuminated on RHS Full 100% Illuminated."— Presentation transcript:
New 0% Illuminated Waxing Crescent 25% Illuminated on RHS First Quarter 50% Illuminated on RHS Waxing Gibbous 75% Illuminated on RHS Full 100% Illuminated Waning Gibbous 75% Illuminated on LHS Third (Last) Quarter 50% Illuminated on LHS Waning Crescent 25% Illuminated on LHS Phases of the Moon
Rising/Meridian/Setting Times PhaseRisingMeridianSetting New6 amNoon6 pm Waxing Crescent9 am3 pm9 pm First QuarterNoon6 pmMidnight Waxing Crescent3 pm9 pm3 am Full6 pmMidnight6 am Waning Gibbous9 pm3 am9 am Third QuarterMidnight6 amNoon Waning Crescent3 am9 am3 pm *Assuming the moon is always on the celestial equator and above the horizon 12 hours per day.
Lunar Periods Sidereal Period – 27.3 days –The time between successive alignments of the earth, moon, and a star –The true orbital period of the moon Synodic Period – 29.5 days –The time between successive alignments of the earth, moon, and the sun –The period of the cycle of lunar phases
Lunar Eclipses Total Lunar Eclipse –The moon is entirely inside the earths umbra Partial Lunar Eclipse –The moon is partially inside the earths umbra Penumbral Lunar Eclipse –The moon is inside the Earths penumbra –These happen regularly and no one notices. The brightness of the moon only decreases by 10% to 20%
Solar Eclipses Total Solar Eclipse –The moon completely obscures the sun for an observer at this location on the Earth Partial Solar Eclipse –The moon partially obscures the sun for an observer at this location on the Earth Annular Solar Eclipse –The moon is near apogee and its angular diameter is insufficient to completely cover the sun. An observer for whom the moon and sun are aligned will see a ring of the sun around the moon
Tides - caused by differential gravitational forces exerted by the moon (the moon pulls more on one side of the earth than the other) -Even though the suns gravitational force is much larger than the moons, its differential force is smaller (since the size of the earth is small compared to the earth-sun distance) -This moons differential force causes water bulges on the earth on both sides of the line to the moon. Tides are caused by the Earths rotation carrying observers through a water bulge. Thus, typically high tide occurs twice a day. -Neap Tides – weak tides which occur when the moons and suns pull are perpendicular -Spring Tides – strong tides when the moon and sun are aligned.