Charon is large in size relative to Pluto, and is locked in a tight orbit with the dwarf planet. A new simulation suggests how it ended up there. By Jonathan O’Callaghan Some 4.5 billion years ago, ...

The formation of the Moon billions of years ago is cloaked in mystery. Most astronomers believe the young Earth, still cooling off from its formation, was struck by a mars-sized body called Theia, ...