Eris is three times more distant than Pluto. And its relationship to Pluto — a world demoted since 2006 from the solar system’s ninth planet to a lowly dwarf planet, in large part due to the ...

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

Pluto isn't alone—it's part of the Kuiper Belt with possibly hundreds of other planet-sized objects. Because Pluto hasn't ...

However, a new study suggests that two of the farthest flung celestial bodies—the dwarf planets Makemake and Eris—could be ...

And I just think it's the coolest world out there, that we know of. Brown discovered the dwarf planet Eris, a breakthrough that helped prompt a new definition of planethood. Eris is my favorite ...

Trans-Neptunian objects (TNOs) are icy bodies that vary widely in size, from large dwarf planets like Pluto and Eris—each ...

The dwarf planet is a bizarre, cryovolcanic world. However, the organic deposits discovered on its surface so far are unlikely to originate from its interior. The organic material found in a few ...

The building blocks of life could have been delivered to solar system dwarf planet Ceres by one or more space rocks from the outer asteroid belt.