Images from NASA's Cassini spacecraft have revealed half-mile-sized (kilometer-sized) objects punching through parts of Saturn's F ring, leaving glittering trails behind them. These trails in the rings, which scientists are calling "mini-jets," fill in a missing link in our story of the curious behavior of the F ring.
Carl Murray: I think the F ring is Saturn's weirdest ring.
We have a new analysis of images obtained by Cassini that show the F ring is actually even more dynamic than we thought.
And for the first time we can see some of the havoc wreaked by objects about a kilometer in diameter.
This movie shows the trail of one of the 500 or so tiny objects that we see punching through parts of the F ring.
We've highlighted the area where these trails can be seen.
These are slow-speed collisions, perhaps just a few meters per second but they drag these glittering ice particles out of the F ring with them.
Cassini scientists have been calling these trails 'mini-jets.'
They look tiny because in the full image you're looking along about 10,000 kilometers of the F ring.
There's a lot of serendipity involved. We were actually concentrating on Prometheus.
What we didn't notice at the time was one of these tiny little trails that sort of sneaked into the field of view.
But now we've done things a bit more methodically. We've actually looked at about 20,000 images.
And we find lots of these little guys and some of them we just caught in the act.
So far we've seen about 500 of these objects in Cassini images.
Some of them may even be the same object.
What's important about these images is that these little guys are the missing link.
We know what Prometheus does. Prometheus creates channels, ripples, snowballs in the F ring.
But what we didn't know was what happened to these snowballs after they were created.
We know also that Prometheus can probably destroy some of these things, just like it can create them and can also change their orbits.
But now we've got evidence that some of the little guys actually survive and they go on to punch through the F ring on their own.
Essentially, we're taking our images of the F ring, removing the planet and exaggerating the radial scale.
Thanks to Cassini we can study all this activity on the F ring over time.
Even during the time that Cassini's been at Saturn, the F ring keeps changing.
NASA Jet Propulsion Laboratory, California Institute of Technology