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

Among the half-dozen is the first known ETNO, the dwarf planet Sedna. The six curiosities that Brown and Batygin identified have elongated elliptical orbits whose perihelia (their closest points ...

A surprising chemical difference between Pluto and Sedna, another dwarf planet in the distant Kuiper Belt, is helping scientists nail down their respective masses, a new study reports.