Astronomy
The Physical Processes Behind Planetary Ring Shepherding Moons
Quick fact
Saturn's moon Pan, only 28 kilometers wide, is responsible for maintaining the 325-kilometer-wide Encke Gap in the A ring, a gap that is much wider than the moon itself.
Why this is interesting
Have you ever wondered why Saturn's rings are so neatly divided into bands, instead of being a smooth, uniform disk? Tiny moons, known as shepherding moons, are the cosmic sheepdogs that keep those rings in line.