The solar system's outer planets host a multitude of irregular satellites
Not long ago, the solar system seemed to be a simple, orderly place. Anyone taking a trip to the local planetarium would have heard that the planets have 60 or so moons orbiting them on neat, nearly circular paths. That picture has now become a lot messier. Over the past 6 years, astronomers have discovered a passel of new moons around Jupiter, Saturn, Uranus, and Neptune, more than doubling the known number.