You’re the Reason We Can’t Have Nice Things

One of Saturn’s rings is broken and it’s all Prometheus’ fault – at least so scientists think. The Cassini spacecraft captured this picture of something disrupting the planet’s thin, delicate “F” ring. This type of event, called a jet, is actually fairly common in the rings, and are caused when something passes through, disrupting the small pieces of ice and stellar debris that make up Saturn’s most iconic feature. In this case, fingers are pointing toward the moon Prometheus as the culprit. That moon, and also the moon Pandora, orbit very close to the F ring and can stir up larger pieces of space rubble that are situated nearby, getting them moving in relation to the ring. Then they pass through, push a bunch of stuff out of the way, and poof, they break things. Cassini has taken images of other jets, but this is the most dramatic.

What are the Rings Made of?

Rings are made of particles consisting of mostly ice, with some rocky material thrown in for good measure. It is the ice, being more reflective than dark rock, that makes them so visible. Theories vary as to when and how the rings formed, but one popular one is that they are the remnants of a small ice moon, maybe 400-600 km in diameter, that was involved in a number of collisions and got smashed into bits. In F ring, the Cassini spacecraft has found 13 larger objects, ranging from 27 meters to 10 km across in size. These may not be solid objects, but rather clumps of smaller ones.

How Many Rings are There?

Saturn boasts seven more visible rings, as well as five more diffuse rings and ring arcs that weren’t discovered until Cassini got close to the planet. There are also numerous gaps and smaller ringlets. The seven original rings are creatively named A through G, while the gaps, diffuse rings, ring arcs, and ringlets have been given more astronomical sounding names. One might think that the A ring is closest to Saturn and G the farthest out, but that’s not the case.

How Wide are the Rings?

F ring, the one broken by meddling Prometheus, is the smallest, ranging from 30 to 500 km. The largest of the original rings is E, which is also the outermost, and measures 300,000 km in width. The others range from 2500 to 25,000 km.

Will Prometheus Ever Behave?

Evidently, these ring jets are a fairly common occurrence because of how close Prometheus and Pandora are, and their propensity to stir things up. So it looks like Saturn is doomed to have its nice things continue to get broken for the foreseeable future.