Oh, we humans do love a cleanly defined boundary, don’t we? They make things easier, after all. If we’re trying to categorize something, knowing what labeled bin to put it in is handy. If we’re ...

The mysterious Oort cloud is the source of many of our solar system's comets, but astronomers still have no idea what it looks like. Now, new simulations may have given them a first glimpse. When you ...

The Kuiper belt, a disc of icy rocks on the outermost edges of the solar system, seems to have more structure than we thought. In 2011, researchers found a cluster of objects there on similar orbits ...