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Moon. Section 19-2. Motions of the Moon. Moon rotation = 27.3 days Moon revolution = 27.3 days Therefore, the same side of the Moon always faces Earth. Phases of the Moon. The different shapes of the Moon as seen from Earth Depends on how much of the sun-side of the Moon faces Earth.
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Moon Section 19-2
Motions of the Moon • Moon rotation = 27.3 days • Moon revolution = 27.3 days • Therefore, the same side of the Moon always faces Earth.
Phases of the Moon • The different shapes of the Moon as seen from Earth • Depends on how much of the sun-side of the Moon faces Earth
Shapes of the Moon • Crescent – small sliver • Quarter – literally ¼ of the moon • Gibbous – not quite round (humpbacked) • Full – completely visible • New – not visible, all dark
Moon-phase Vocab • WAXING • In this ½ of the cycle, the visible part of the moon is getting bigger. • It is building up, like a “waxy build-up” • WANING • In this ½ of the cycle, the visible part of the moon is getting smaller • It is “waning” away
We see: We see: We see: ? We see: We see: We see: We see: We see:
The Lunar Cycle One full cycle of the moon = 29.5 days.
Eclipses • When the moon’s shadow hits Earth or . . . • When Earth’s shadow hits the Moon
Solar Eclipse • Moon is between Earth and Sun • Moon’s shadow on Earth blocks out Sun
Solar Eclipse • TOTAL Solar Eclipse occurs in the UMBRA • The Umbra is the darkest part of the moon’s shadow.
Solar Eclipse • PARTIAL Solar Eclipse occurs in the PENUMBRA • The Penumbra is the larger and less dark part of the moon’s shadow.
Lunar Eclipse • Earth blocks sunlight from reaching the Moon • Occurs only at full moon • Moon will look red
Next Eclipses 2008 • 2008 Feb 07: Annular Solar Eclipse • 2008 Feb 21: Total Lunar Eclipse • 2008 Aug 01: Total Solar Eclipse • 2008 Aug 16: Partial Lunar Eclipse 2009 • 2009 Jan 26: Annular Solar Eclipse • 2009 Feb 09: Penumbral Lunar Eclipse • 2009 Jul 07: Penumbral Lunar Eclipse • 2009 Jul 22: Total Solar Eclipse • 2009 Aug 06: Penumbral Lunar Eclipse • 2009 Dec 31: Partial Lunar Eclipse
Tides • Caused by the gravitational pull of Moon on Earth • 2 tide cycles per day