Two nearly-identically sized worlds — Eris and Pluto — float distantly in the same frozen region of our outer solar system. A NASA spacecraft has visited Pluto, but not Eris, and each is so distant ...

WASHINGTON (Reuters) - Dwarf planet Eris, similar in size to its better-known cosmic cousin Pluto, has remained an enigma since being discovered in 2005 lurking in the solar system's far reaches.

University of California, Santa Cruz Professor of Planetary Sciences Francis Nimmo recently co-authored a Science Advances paper about the internal structure of the dwarf planet Eris. Eris is about ...

In the outer Solar System, the dwarf planet Eris is locked in a mutual dance with its moon Dysnomia 1. Eris, the most massive object known in the Solar System beyond Neptune, is so distant that it ...

PASADENA, Calif.–Die-hard Pluto fans still seeking redemption for their demoted planet have cause for despair this week. New data shows that the dwarf planet Eris is 27 percent more massive than Pluto ...

The International Astronomical Union announces the names (136199) Eris for the dwarf planet provisionally named 2003 UB313 and Dysnomia for its Moon. The dwarf planet formerly known as 2003 UB313 ...

NASA’s Hubble Space Telescope has teamed up with the W.M. Keck Observatory to precisely measure the mass of Eris, the largest member of a new class of dwarf planets in our solar system. Eris is 1.27 ...

A depiction of Eris’s rocky core and ice shell on an illustrated background from NASA. Credit: University of California - Santa Cruz A depiction of Eris’s rocky core and ice shell on an illustrated ...