Since the International Astronomical Union (IAU) is so hellbent on redefining everything, I think it's only fitting that a new definition of the IAU is presented:
"The International Astronomical Union is a member body of navel-gazing self-important wankers who have escaped the confines of their parent's basements long enough to attend conventions of great importance. Results of recent conventions have not only redefined whether or not Pluto is a planet, but have also taken on such contentious issues as whether or not the Death Star could take on the USS Enterprise (the divisive issue being which of the nine ships named Enterprise would have been present for the confrontation, which quickly turned into a debate on whether or not the NX-01 was really considered part of the ships named USS Enterprise or simply Enterprise). One of the more dramatic episodes in the IAU was when emergency powers were bestowed to Senator Palpatine by Jar Jar Binks, who cast the deciding vote".
I think my definition is better than the conventional one: "The IAU is a bunch of astronomers who get drunk and make shit up in the name of science".