Eris was one of the first dwarf planets to be discovered in the solar system. It is almost the same size as Pluto, and its discovery directly led to the former ninth planet's demotion. Eris also has a ...

Eris is the largest dwarf planet in the Solar System, and the ninth largest body orbiting our Sun. Sometimes referred to as the “tenth planet,” its discovery is responsible for upsetting the ...

Though the dwarf planet Eris on the edge of the solar system is much denser than Pluto, the two frigid worlds are nearly exactly the same size, a new study finds. Astronomers accurately measured Eris' ...

Despite being three times farther from the sun than Pluto, the dwarf planet Eris could almost be the demoted planet's twin—just with a truly icy atmosphere. According to new observations, Eris is not ...