(Well, not so much "breaking" anymore, since it is usually some time after I write these things that I finally get them posted. But, late is better than never.)
Pluto, along with a cadre of other planetoidal pretenders, has officially been demoted. It is too small and has much too eccentric an orbit around the sun to be classified as a planet. Thus spake the International Astronomical Union.
This news is apt to make a lot of second graders very unhappy, but does put some amount of logic back into the selection process. Scientists should use logic whenever possible.