NASA's Perseverance rover might be out there on Mars since 2021, collecting rock samples and finding hints of water, but that doesn't mean its predecessor has already retired from its explorations. In fact, the Curiosity rover has been observing Martian clouds during twilight to build upon its previous survey on night-shining clouds. And on February 2nd, Curiosity captured a rare sight on camera, making it the first time we've seen crepuscular rays (or "sun rays") this clearly from the Martian surface.
The clouds in the photo above are located at a higher altitude than most Martian clouds, which sit around 37 miles above the ground and are made of water ice. Since the clouds in the photo are higher up where it's especially cold, NASA thinks they're made of frozen carbon dioxide — or dry ice, as we call it — instead. They agency says that observing clouds on Mars can help scientists learn more about the planet's atmospheric conditions, temperatures and winds.
For this particular survey, which started in January and will conclude mid-March, Curiosity mostly uses its colored Mast Camera or Mastcam. The equipment allows the rover to take images that would show scientists how cloud particles glow over time. To create the panorama you see above, NASA stitched together 28 images taken by the Mastcam. In 2021, though, Curiosity mostly relied on its black-and-white navigation cameras that provided us a detailed look at clouds' structure as they move.
In addition to our first clear view of the Martian sun rays, the rover has also taken photos of other interesting cloud formations since the current survey began. One image from January 27th (below) shows an iridescent cloud that's shaped like a feather. Apparently, the color transitions brought about by iridescence tell scientists how the cloud is evolving and about how its particle size is changing across the structure.