The relative quantities of volatile gases like methane and ethane can reveal key details about distant Kuiper Belt objects.

There are five known dwarf planets in our solar system. One of them is named Ceres, after the Roman goddess of corn, agriculture, and harvests. Ceres is the closest dwarf planet to the sun.

For the better part of a century, we believed there were nine planets in our solar system, with Pluto being the farthest from the sun. Since the discovery of more Pluto-sized dwarf planets, that ...