What’s up with that brown splotch sprawling across a broad swath of the South Pacific in the upper right corner of this satellite image?
Nope, it’s not some black hole that has just materialized in the middle of the ocean, threatening to suck New Guinea and Australia into its depths. Neither is a gargantuan oil spill, or a massive bubble of air pollution that’s drifted in from China.
What happened on May 10 northeast of Australia was completely natural and unthreatening: an annular eclipse of the sun. When this kind of eclipse happens, the moon passes in front of the sun, but it doesn’t black it out completely. That’s why the shadow cast onto the ocean in this image captured by NASA Terra satellite is not completely black and opaque. Some sunlight is getting through, producing more of a brown-out. (The black stripes are areas not imaged by Terra.)
Here’s what the X-Ray Telescope on the Hinode spacecraft saw when the moon passed between it and the sun:
In an annular eclipse, the moon lines up in just the right way to allow only a fiery ring to be seen around its dark disk. That wasn’t the case here because Hinode was seeing the sun from a perspective in which the moon wasn’t perfectly aligned.
Lastly, here’s an image from closer to home:
The outlined areas in the image are the Solomon Islands.