Six images of the mini-jets taken by Cassini between 2005 and 2008. Credit: {link url=""}NASA/JPL-Caltech/SSI/QMUL{/link}

Objects half a mile in diameter have been spotted punching through Saturn's outermost ring, the F ring, and leaving glittering trails as they drag icy particles behind them. Scientists are calling these trails mini-jets.

The scientists were actually looking at Prometheus, one of Saturn's small moons, when they saw the first of the trails. They went back to look for more and, after combing through all 20,000 of the seven years' worth of Cassini images, found around 500 of them.

Prometheus is no stranger to disrupting the F ring. It creates channels and ripples in the ring, and the snowballs themselves too. But scientists didn't know what happened to the snowballs after they were created. These images show that some of them survive and go on to push through the F ring on their own.

"These little guys are the missing link," says Carl Murray, a Cassini imaging team member based at Queen Mary, University of London, who narrates a video explaining the finding. If you are interested in how Cassini scientists study images of Saturn and the F ring, watch the video right until the end.