Dysnomia is the only known moon of the Kuiper Belt dwarf planet Eris. It’s the second-largest known moon of a dwarf planet, after Pluto’s moon Charon. It is named Dysnomia after the daughter of the Greek goddess Eris. The Ancient Greek word Δυσνομία means anarchy/lawlessness.

Eris is the bright object in the center of the image. Dysnomia is the smaller dot at about 8 o’clock.

Image Credit: NASA

A New Moon

A moon was discovered around the dwarf planet 2007 OR10 in these archival Hubble images. They were taken a year apart and reveal a moon orbiting the dwarf planet. Each image, taken by the Hubble Space Telescope‘s Wide Field Camera 3, shows the companion in a different position around the planet. 2007 OR10 is the third-largest known dwarf planet, after Pluto and Eris, and the largest unnamed body in the solar system. It’s located in the Kuiper Belt, a realm of icy debris left over from the solar system’s formation.

Image Credits: NASA / ESA / C. Kiss (Konkoly Observatory) / J. Stansberry (STScI)