Eclipses - What is an eclipse of the moon?
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Eclipse of the Moon

Eclipse of the moon in Italy

An eclipse of the moon happens when the Earth gets between the sun and the moon, so the light from the sun can't get to the moon to be reflected towards the Earth. In other words, the shadow of the Earth covers the whole moon.

A total eclipse of the moon can only happen when the moon is full, because that's when the moon is exactly opposite from the sun in the sky. The moon is full about once a month, but eclipses happen less often because sometimes the moon is too high or too low for the Earth's shadow to fall on it. Usually lunar eclipses (eclipses of the moon) happen two to four times a year.

The moon and eclipses of the moon

Sometimes they are full eclipses, and sometimes only part of the moon is eclipsed. When there's an eclipse of the moon, anyone on the night side of Earth can see it.

Eclipse of the Sun
Understanding the eclipse
More about the Moon
Learn by doing - eclipses

Bibliography and further reading about space:

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Copyright 2012-2015 Karen Carr, Portland State University. This page last updated September 2015.

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