Darkness swallows daylight, a sudden chill seizes the air, the sun disappears from the sky—it’s no wonder our ancestors got pretty freaked out by solar eclipses.

Many cultures thought solar and lunar eclipses occurred when the celestial bodies were consumed by supernatural forces, like the fire dogs of Korea, the sky wolves of the Vikings, or the disembodied head of a Hindu demon. (Watch a three-hour eclipse in one minute.)

While the heliocentric model of the universe tied things up a bit, astronomers eventually figured out that solar eclipses are caused by the moon passing between the sun and Earth, and lunar eclipses are caused by Earth passing between the sun and the moon.

Through careful observation, early astronomers