Math in… Solar Eclipses

A solar eclipse occurs when the moon is aligned between the earth and sun so that it blocks the sun’s light for a small chunk of the earth. Since these three bodies move relative to one another, predicting when this alignment happens requires some math!

Modern astronomers are good at modeling this three-body problem with computers and calculus, allowing them to predict the times of eclipses with great accuracy.

Eclipses occur in saros cycles of about 18 years, tracked by the phases of the moon. With careful record-keeping, ancient peoples around the world have been able to predict the days of eclipses without computers!