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.

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 ...

In 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. In 2008, tribal violence ...

It saw the discovery of dwarf planet Eris and how those very observations led to a new way to describe the Solar System and heralded the eventual change of Pluto’s planetary status. On that ...

is a disc-shaped region beyond the orbit of Neptune’s in the outer solar system—50 Earth-sun distances—that’s home to dwarf planets like Pluto, Makemake and Eris. It’s also thought to be ...

For one thing, Eris shares the region and isn't stuck in Pluto's orbit. The end result? Pluto is bumped from "planet" to "dwarf planet." Now, Stern argues that a dwarf planet is a kind of planet.