During a total solar eclipse, the moon blocks out the entire disc of the sun. But as we know, the moon isn't a perfectly round, perfectly smooth, mass. It's pocked with craters and crags.
Bits of light can sneak through those crevices during a solar eclipse. And they create the "diamond ring" effect you can see in the image below, captured during the total solar eclipse in Indonesia yesterday.
The bright spot in upper left is known as a Baily's bead, named after the astronomer who discovered the phenomenon. It is the result of light taking advantage of the moon's uneven topography and shining its way through. The yellow glow around the black disc is the sun's corona, or atmosphere.
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In this image, you can also see a red prominence sticking out around the midline — a mass of plasma that's floating above the sun's surface. Prominences can explode in what's called a coronal mass ejection, which sends matter and energy hurtling thought space.
This photo isn't just awesome because it's pretty. It's awesome because it shows the sublime power of the sun: That one bead of light is still intense enough to cause eye damage. It also gives us a chance to appreciate the random, relatively tiny details of the moon. That this could only be seen in a 90-mile-wide line across a stretch of the Pacific Ocean, for just a few moments, makes it even more rare and all the more awe-inspiring.
Here's what it looked like on the live feed of the event:
(Screen capture/Exploratorium)
