Eclipses occur because the moon and Earth are always moving. Earth orbits, or goes around, the sun. And at the same time, the moon orbits Earth.
As Earth and the moon travel in their orbits, sometimes Earth moves between the sun and the moon and blocks the sunlight that normally reaches the moon. We call this an eclipse of the moon, or a lunar eclipse.
At other times as the moon orbits Earth, it passes between the sun and Earth. Now the moon blocks the sun and casts a shadow onto Earth. We call this an eclipse of the sun, or a solar eclipse.
If the sun, moon, and Earth are not lined up straight, the moon blocks only part of the sun. The center of its shadow—the darkest part—misses…
