Skip to main content
K12 LibreTexts

3.11: Lunar Eclipses

  • Page ID
    5349
  • alt

    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 20, 2019, May 26, 2021, May 15, 2022, and November 8, 2022.

    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.

    Check out the video below for more information about the super blue moon which occurred on January 31, 2018 which had an added bonus of a lunar eclipse.

    Summary

    • 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.

    Review

    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?
    • Was this article helpful?