Why isn't there an eclipse every full moon?
A lunar eclipse happens when the Earth, sun and moon align in space, with Earth in the middle. At such times, Earth’s shadow falls on the moon, causing the lunar eclipse. So why isn’t there a lunar eclipse during every full moon?
The moon takes about a month to orbit around the Earth. If the moon orbited in the same plane as Earth’s orbit, we would have two eclipses every month. There’d be an eclipse of the moon at every full moon. And, two weeks later, there’d be an eclipse of the sun at new moon – for a total of at least 24 eclipses every year.
But the moon’s orbit is inclined to Earth’s orbit by about 6 degrees. That’s why there’s not an eclipse every month.
Still, there are more eclipses than you might think. There are from four to seven eclipses every year. Some are lunar, some are solar, some are total, and some are partial. All are marvelous to behold – a reminder that we live on a planet – a chance to experience falling in line with great worlds in space!
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