From the cratered companion that lights Earth's night sky to the hundreds of icy worlds circling the Solar System's giant ...

Jupiter, Saturn, Uranus and Neptune did not always have their current positions in the solar system. According to the planetary-instability model, they were born a little closer to the Sun and closer ...

So far, humanity has yet to find its first "exomoon"—a moon orbiting a planet outside of the solar system. But that hasn't been for lack of trying. According to a new paper by Thomas Winterhalder of ...

Add Yahoo as a preferred source to see more of our stories on Google. When you buy through links on our articles, Future and its syndication partners may earn a commission. An illustration of Uranus ...

The outer solar system once seemed like a quiet backwater. But a glut of tiny, strange moons with unruly orbits are coming into view, revealing hints of a surprising past – and the origin of Saturn's ...