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Lunar Eclipses

The alignment of the Sun, Moon and Earth leads to a lunar eclipse; what happens during one.

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Lunar Eclipses

Can you see a lunar eclipse?

Again, of course! Anyone with a view of the Moon can see a lunar eclipse. The next four total lunar eclipses predicted for North America will be on January 31, 2018, July 27, 2018, January 20, 2019, and May 26, 2021.

Lunar Eclipses

Sometimes a full moon moves through Earth's shadow. This is a lunar eclipse (Figure below). During a total lunar eclipse, the Moon travels completely in Earth’s umbra. During a partial lunar eclipse, only a portion of the Moon enters Earth’s umbra. When the Moon passes through Earth’s penumbra, it is a penumbral eclipse. Since Earth’s shadow is large, a lunar eclipse lasts for hours.

The moon's position during a lunar eclipse

A lunar eclipse.

Partial lunar eclipses occur at least twice a year, but total lunar eclipses are less common. The Moon glows with a dull red coloring during a total lunar eclipse (Figure below).

A lunar eclipse is shown in a series of pictures

A lunar eclipse is shown in a series of pictures.


  • During a lunar eclipse, the full moon moves through Earth's shadow.
  • Earth's shadow is large so lunar eclipses last longer than solar eclipses. They cover more area too.
  • The umbra is the part of the shadow in which light is completely blocked.
  • The penumbra is the part of the shadow that is partially lit.


  1. What causes a lunar eclipse?
  2. Why are you more likely to see a lunar eclipse than a solar eclipse?
  3. When does a lunar eclipse occur?

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    lunar eclipse Eclipse that occurs when the Moon moves through the shadow of the Earth and is blocked from view.

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