Mass of Dwarf Planet Eris 27% Greater than Pluto

jcgam69 writes "When it was discovered in 2005, some thought Eris should be considered the 10th planet of our solar system. Everyone still considered Pluto a planet then. At first, Eris was thought to be slightly larger. Now — with the help of Eris' moon — Eris is known to be 27% more massive than Pluto. If Pluto had remained a planet to the entire community of astronomers, surely Eris would be considered the 10th planet."

Comments

Re:Where is this "clean" ontology you speak of?

[CorSci81]

Pluto won't clear its orbital path in the lifetime of the sun for a few reasons. The Kuiper Belt (where Pluto resides) is a very excited region of the solar system in terms of orbital eccentricities and inclications, which results in a very high mean impact velocity between objects out there. This means impacts tend to be destructive rather than letting anything grow larger. Additionally the number of particles in the Kuiper belt is sufficiently small impacts are fairly rare. Basically, the Kuiper Belt never became a planet for much the same reason the asteroid belt hasn't.

Regarding the two planets bit, that's a highly unstable orbital configuration. If they orbited a common center of mass (like the Earth and moon) it would be feasible, but then we'd just call them a twin planetary system, or the smaller of the two would be considered a moon.