Friday, October 5, 2012

The weird, black, spidery things of Mars

See those weird, black, spidery things dotting the dunes in this colorized photo taken by the Mars Reconnaissance Orbiter in 2010? Yeah. Nobody knows what the hell those things are.

What we do know about them just underlines how incredibly unfamiliar Mars really is to us. First spotted by humans in 1998, these splotches pop up every Martian spring, and disappear in winter. Usually, they appear in the same places as the previous year, and they tend to congregate on the sunny sides of sand dunes — all but shunning flat ground. There's nothing on Earth that looks like this that we can compare them to. It's a for real-real mystery, writes Robert Krulwich at NPR. But there are theories: