Pluto: January 2015

Based on stories in the New York Times (and elsewhere) it would seem that the NASA New Horizons mission team is redefining what it means to be a "planet" and a "moon". Do NASA and the IAU agree?

NASA's New Horizons spacecraft recently began its long-awaited, historic encounter with Pluto.

There could be at least two unknown planets hidden well beyond Pluto, whose gravitational influence determines the orbits and strange distribution of objects observed beyond Neptune.

"... the probability that there is one or more remaining outer solar system object of this brightness left to be discovered in the unsurveyed regions of the galactic plane is approximately 32%."