Curiosity rover offers a rare glimpse of cloudy days on Mars

NASA’s Curiosity rover just spotted a rarely-seen event on Mars: a cloudy day. The agency has shared images of “shining” clouds (produced by ice crystals reflecting light) that started appearing over the Curiosity site starting in late January. They’d be pedestrian here on Earth, but they’re notable for a planet with a very thin atmosphere and have even led to a discovery of their own.

The mission team has determined that these clouds are higher than usual for Mars, floating well above the 37-mile peak altitude for the planet’s water-ice clouds. That raises the possibility they’re dry ice clouds formed out of frozen carbon dioxide, and might reveal more about the Martian sky.

NASA noted that the clouds were easiest to see with Curiosity’s black-and-white navigation cameras, but that the color mast camera produced the best shine.

This might not be the most dramatic event on Mars at the moment. It does, however, serve as another reminder that the planet isn’t a static set of images. Mars is a dynamic world with ever-changing weather, even if it isn’t as lively as it was in the distant past.