Why did Pluto lose its planet status? Because it never mattered enough

[img]http://www.blogcdn.com/www.engadget.com/media/2010/12/10x1230ub379luto.jpg
[/img]It's kind of hard to accept, Pluto has always been our favorite
underdog, but the truth is that the Solar System's ninth planet was
never really significant enough to earn that designation. Such is the
coldly logical reason given for its removal from the planetary annals
by a man who had a lot to do with its demise. Caltech astronomer Mike
Brown discovered Eris, what he'd hoped was the tenth planet, back in
2005, but its extreme distance from the Sun and diminutive (by
planetary standards) dimensions disqualified it from consideration.
Unfortunately, its discovery is what doomed Pluto to be downgraded to
a "dwarf planet," though Mike's not shedding too many tears over it.
In fact, he's gone and written a book about the whole thing, the smug
planet destroyer that he is. You don't have to buy it to learn more,
however, as the source link has an interview with Mike all ready and
waiting.