Inside Saturn's outermost ring, NASA's Cassini probe has captured activity that researchers liken to a cosmic snowball fight. Hundreds of balls of snow and ice up to half a mile in diameter have been spotted punching through the F ring at gentle speeds, leaving glittering trails behind them, the BBC reports. The snowballs are created by moons like Prometheus, which move along the outside of the ring, and researchers believe some of them survive to become moonlets of their own.
"I think the F ring is Saturn's weirdest ring, and these latest Cassini results go to show how the F ring is even more dynamic than we ever thought," a Cassini team member says. "These findings show us that the F ring region is like a bustling zoo of objects from a half mile in size to moons like Prometheus a hundred miles in size, creating a spectacular show." Researchers believe the activity inside Saturn's rings is similar to what happened in the ring of material that gathered around the sun billions of years ago and eventually became the planets. (Read more Cassini stories.)