One of Saturn’s moons is building enormous snowballs in the gas giant’s famous rings. Images from NASA’s Cassini orbiter show how icy particles in Saturn’s thin F ring clump together in snowballs up to 12 miles in diameter as the moon Prometheus swings around the ring.

“Scientists have never seen objects actually form before,” said planetary scientist Carl Murray of Queen Mary, University of London in a press release. “We now have direct evidence of that process and the rowdy dance between the moons and bits of space debris.” Murray presented the findings July 20 at the Committee on Space Research meeting in Bremen, Germany, and they appear in the journal Astrophysical Journal Letters on July 14.

I love the splashy full-color pictures of Saturn, but sometimes grayscale (or what is commonly, and incorrectly, called black-and-white) is what’s needed to capture a mood. Take a look at Cassini’s latest view of the ringed planet:

Sigh. Oh my. Click to enjovianate.

After yesterday’s depressing picture, how about one that will make you smile?

The ever-amazing Cassini spacecraft sent back this pretty nifty shot of Saturn’s icy moon Rhea playing peekaboo in the rings:

Beautiful, isn’t it? You can see that Rhea was on the other side of the rings from Cassini when this image was taken, and that the spacecraft was almost, but not quite, in the plane of the rings, too.