When astronomers found a large world farther out than Pluto, it became one of the final nails in the coffin of our ninth planet.

January 5, 2005, is an astronomical anniversary that is not really marked but should be. It saw the discovery of dwarf planet Eris and how those very observations led to a new way to describe the ...

On Jan. 5, 2005, Eris was discovered. It was considered the largest known dwarf planet in the solar system until a year later when Pluto was downgraded from being a planet.

On this day in 2005, planetary scientists announced the discovery of Eris. Initially thought to be the tenth planet, Eris is the most massive and second-largest known dwarf planet in the Solar ...

The recent study of the dwarf planets Eris and Makemake reveals that they could be compatible with the emergence of extraterrestrial life. The dwarf planets of the Solar System, such as Ceres, Haumea, ...

The dwarf planets in question, Eris and Makemake, are both found in the Kuiper Belt past Neptune's orbit and are far from the Sun's warmth, similar to fellow dwarf planet Pluto.

Pluto's 'almost twin' dwarf planet Eris has a rocky core blanketed by an icy shell, which appears to be flexing slowly.

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.

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 ...

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. While Pluto was ...