Makemake and Its Moon (Artist's Concept)

This artist's concept shows the distant dwarf planet Makemake and its newly discovered moon. Makemake and its moon, nicknamed MK 2, are more than 50 times farther away than Earth is from the Sun.

The pair resides in the Kuiper Belt, a vast reservoir of frozen material from the construction of our Solar System 4.5 billion years ago. Makemake is covered in bright frozen methane that is tinted red by the presence of complex organic material. Its moon is too small to retain ices as volatile as methane, even given the feeble heating by the very distant Sun, and likely has a much darker surface. MK 2 is orbiting 21,000 kilometres from the dwarf planet, and its estimated diameter is roughly 160 kilometres across. Makemake itself is 2200 kilometres across.