Total solar eclipse
Hey, who turned out the lights? Sometimes the answer is: the moon!
About every 18 months, somewhere on Earth experiences a total solar eclipse—when the moon completely blocks the sun. But for you, it’s probably a special event: Total solar eclipses only occur in the same location about once every 375 years.
During a total solar eclipse, the sky appears dark, the temperature drops, and some animals even change their behavior. Perhaps thinking it’s nighttime, some cows will return to their barns, crickets chirp, and nocturnal bats take flight.
But be careful: Direct light from the sun can burn the cells in your eyes, causing blindness. The sun is only completely blocked by the moon for a few moments during a total solar eclipse, so to safely experience the solar show, use special-purpose eclipse glasses or a solar viewer to block the harmful rays.
How a total solar eclipse happens
Most days, the moon orbits around Earth but doesn’t come directly in between the Earth and the sun. So it doesn’t block the sun’s light, which creates daytime on half of Earth. But that changes during an eclipse, when the sun, moon, and Earth line up exactly. In this position, the moon can completely block sunlight from reaching a part of Earth.
(When the moon lines up but is orbiting at its furthest point from Earth, it creates an annular solar eclipse and a ring of sun is still visible behind the moon.)
As the moon moves and the Earth spins, circular shadow about a hundred miles wide races across Earth’s surface at about 1,500 miles an hour. Within the shadow, the sun is completely blocked by the moon, creating a total solar eclipse that looks like nighttime.
Just outside the shadow of the total solar eclipse, people will experience a partial solar eclipse where the sun isn’t completely blocked. Here, it looks like somebody took a bite out of the sun.
Sky Stories
- Ancient Chinese people said that a dragon ate the sun during an eclipse. They’d bang drums and used firecrackers to scare the beast away.
- One legend from the Choctaw people of the American Southeast says that a mischievous squirrel gnawed on the sun to create an eclipse.
- A tale from the Hindu religion says that a demon was beheaded when he tried to swallow the sun. The sun disappears at first—but then reappears because he has no body.