Eight billion miles (14 billion kilometers) from Earth, at the solar system’s ragged edge, lies Eris — a planet-sized oddball of a world that emerged unexpectedly from the darkness 20 years ago.

The number of planets that orbit the sun depends on what you mean by “planet,” and that’s not so easy to define ...

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 ...

Brown’s team discovered a dwarf planet, Eris, in January 2005. At the time, it appeared to be larger than Pluto. If Pluto hadn’t been demoted, Brown says, hundreds of celestial objects would ...

Although Seeing in the Dark doesn't directly discuss Pluto, it does celebrate the joy of observing planets. Viewers who watch the show may wonder what happened to Pluto in 2006 and whether any of ...

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 following ...