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

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

Named Eris and Makemake, these celestial bodies ... the prospect of finding water in the icy outer reaches of our solar ...

However, we actually have six in our Solar System. Pluto, Ceres, Makemake, Haumea, and Eris were the only five that we knew about up until very recently. Ceres is in the asteroid belt between Mars ...

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 ...