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Lunar Eclipse Definition

A lunar eclipse occurs when the Moon moves into Earth's shadow. For example, a total lunar eclipse completely covers the Moon with Earth's shadow.

View Lesson on Solar & Lunar Eclipses
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Solar & Lunar Eclipses

Fun Facts

  • Lunar eclipses can occur only when the Moon is full.
  • Total lunar eclipses occur about once every two years.
  • A Blood Moon appears reddish during a total lunar eclipse.

Why Do We Need To Know About Lunar Eclipse

Learning about lunar eclipses helps us see why space scientists, called astronomers, find them exciting. These scientists study space and learn about distant planets by watching how they move in front of stars, blocking some of their light, which looks a bit like an eclipse from far away.

This technique has helped find more than 2000 planets, and some of these could even have life, like the planet Kepler 62F. So, understanding eclipses is not just cool, but it’s also key to finding new worlds and maybe even life outside our planet.

Frequently Asked Questions

If the Sun is so much larger in size than the Moon, why do they appear to be the same size?
The Moon is about 400 times smaller than the Sun and about 400 times closer to Earth. Those proportions cause the Sun and the Moon to look about the same size.
Why was it important that Dr. Jeff use a large ball to represent the Sun, a marble to represent Earth, and a bead to represent the Moon in his model?
Although all models have limitations, Dr. Jeff was trying to accurately represent the size of each object in the Earth-Sun-Moon system relative to one another.
How would the Earth-Sun-Moon system change if the Moon’s orbital plane weren’t tilted 5°?
We would have an increase in the number eclipses we can see because of the orbit of the Moon around Earth.
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