Earth Science

Earth as a Planet

Eclipses

Study Tip
The same way a person may cast a shadow over another person when they stand under the sun, planets or celestial bodies that have aligned themselves cast shadows over one another as well.

Solar Eclipses

  • A solar eclipse is when a New Moon passes in between the Sun and the Earth, casting a shadow on the Earth.
  • The umbra is the part of the shadow in which light is completely blocked and the penumbra is the part of the shadow that is partially lit.
  • Solar eclipses are rare, and they only last for a few minutes because the shadow from the Moon is relatively small.
  • When the Moon’s shadow completely blocks out the Sun, a total solar eclipse occurs, and when only a portion of the Sun is blocked a partial solar eclipse occurs.
Study Tip
The same way a person may cast a shadow over another person when they stand under the sun, planets or celestial bodies that have aligned themselves cast shadows over one another as well.

Lunar Eclipses

  • A lunar eclipse happens when a Full Moon passes through the Earth’s shadow.
  • Because the Earth’s shadow is relatively large, a lunar eclipse can last for several hours.
  • A lunar eclipse doesn’t happen every month because the Moon has a 5 degree incline in relation to its orbit around the Earth.
  • The Moon during a lunar eclipse usually turns a dull red.
lunar eclipse
During a lunar eclipse,
the Earth’s shadow covers the Moon.
solar eclipse
During a solar eclipse,
the Moon’s shadow covers the Earth.
Concept Check
  • Consider the shadows casted by the planets during each type of eclipse. Which body casts a shadow in each case?