anthony morris


  • Occurs when any part of the Earth or Moon enters the shadow of the other
  • The darkest part of the shadow the umbra
  • The lighter, more diffuse region of the shadow is called the penumbra
  • The Moon is usually sufficiently above or below the ecliptic plane to avoid an eclipse
    • The paths cross twice a year

Solar Eclipse

Solar eclipse

Geometry of a total solar eclipse

  • Moon's shadow covers the Earth and partially hides the Sun
  • Total solar eclipse
    • When the Moon is close to its average distance from the Earth, it can cover the Sun completely
    • Very small area on the Earth
    • Eclipse path travels at 1500 km/hour

Lunar Eclipse

Geometry of a lunar eclipse

  • Earth's shadow covers the Moon
  • Can only occur when the Earth/Sun/Moon are in line
  • Total lunar eclipse
    • The Moon's path must go through the Earth's umbra

Space Astronomy Earth Moon Sun