The third-largest object known beyond Neptune, 2007 OR10, has a moon. The discovery was reported in a poster by Gábor Marton, Csaba Kiss, and Thomas Mueller at the joint meeting of the European Planetary Science Congress and the Division for Planetary Sciences of the American Astronomical Society (DPS/EPSC) on Monday.
January 24 was the 30th anniversary of the Voyager flyby of Uranus. Uranian moons have been on my mind ever since New Horizons sent us close-up images of Charon. On the occasion of the anniversary, Ted Stryk produced latest-and-greatest versions of the Voyager views of these worlds.
It's looking likelier that there is an undiscovered planet orbiting beyond the Kuiper belt. If it's there, it's roughly 10 times the mass of Earth (or about half the mass of Neptune), likely never gets closer to the Sun than about 100 AU, and takes more than 10,000 years to orbit the Sun.
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