The Moon

  • Has a nearly circular orbit around the Earth
  • Perigee distance, the closest distance the moon is from Earth, is 363 000 km.
  • Apogee distance, the furthest distance the moon is from Earth, is 405 000 km.
  • One rotation takes 27.3 days
  • One revolution around the Earth takes 27.3 days
  • Reflects light from the Sun
  • No atmosphere so all UV rays from the Sun reach the surface
  • Gravity is only 16 of the Earth's gravity
  • Craters are deep depressions on the surface caused by meteorites
  • Maria (or 'seas') are large smooth areas on the surface covered by plains of grey basalt - like rock
  • Lunar highlands and rilles (long steep-sided valleys) cover the rest of the surface
  • Earth's moon is only the 5th largest moon in the solar system.

The Phases of the Moon

  1. New Moon - The face of the Moon facing Earth is completely in shadow ('No Moon'). The Sun, the Moon and the Earth are in line.
  2. Waxing Crescent - A horn-shaped part of the Moon is illuminated.
  3. First Quarter - Only half of the face of the Moon facing Earth is illuminated.
  4. Waxing Gibbous - More than half of the face we see is illuminated.
  5. Full Moon - All of the face we see is illuminated. The Sun, the Earth and the Moon are in a line.
  6. Waning Gibbous - More than half of the face we see appears lit.
  7. Last Quarter - Only half of the face we see appears lit.
  8. Waning Crescent - A horn-shaped part of the Moon facing Earth is illuminated.

Moon Phases Diagram



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