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 learned to predict when eclipses would occur. The Chaldeans of Babylon first recorded the Saros cycle—a period of 18 years and 11.3 days between recurring eclipses—in the seventh century B.C.
However, it’s taken us a very long time to figure out how to truly protect our eyeballs when viewing an eclipse. (Plan ahead for the top seven must-see sky events for 2017.)
This year, sky-watchers are gearing up for the first total solar eclipse visible from the continental U.S. since 1979. Take a look through these photos of historic eclipses from around the world (including the one that made Albert Einstein famous). Then grab some popcorn and a pair of eclipse glasses, sit back, and get ready to watch the "great American eclipse," coming to a sky near you this August.