Pluto's dinky diameter wasn't the official reason it was demoted from the planetary club back in 2006, but symbolically, size was the last straw. When Caltech astronomer Mike Brown spotted the object we now call Eris back in 2005 and astronomers figured it to be larger than Pluto, the former ninth planet's fate was sealed. Now Pluto's reclassification as a "dwarf planet" and the subsequent public outcry is behind us, but new research suggests that the former planet's symbolic death knell—Eris' s
