A ring-crossing is where Saturn’s rings seem ... around a planet at the same time as the planet itself forms. Irregular moons are thought to be small planets (planetesimals) that are captured ...

A ring-crossing is where Saturn’s rings seem ... around a planet at the same time as the planet itself forms. Irregular moons are thought to be small planets (planetesimals) that are captured ...

The moons that orbit Uranus are already known to have unusual characteristics: some are heavily cratered, others have ...

For example, ring particles — the tiny fragments of ... circular orbits close to the equator of their host planet; and irregular moons, which can be much smaller and have larger, more elliptical ...

Most of the rings have a prograde orbit, in the same direction as Saturn, but the outermost (the Phoebe ring) is thought to originate from Phoebe, the largest of Saturn's irregular moons—and ...

These are called "irregular moons" because they aren't neatly spherical like our moon. But they were born in dramatic circumstances. The little moons are grouped cliquishly together, suggesting ...