A little moonlet, too small to be seen from Earth, could be playing cosmic sheepdog by shaping the thin rings around the distant minor planet Chariklo, according to new computer simulations.
Chariklo is a Centaur — a breed of small body that orbits the sun on a path sandwiched somewhere between Jupiter and Neptune. Centaurs are thought to come in from the Oort Cloud, which is a vast halo of trillions of frozen cometary bodies that extends possibly a light-year from the sun. Over the course of millions of years, they drift inward, either to be ejected from the solar system by the gravity of the giant planets, or to transition into Jupiter-family comets — comets with orbital periods of less than 20 years that are governed by the gravity of mighty Jupiter.
