Quote:
Originally posted by Scientific American.com
Rejecting an expansive definition proposed by a special committee, the astronomers of the International Astronomical Union (IAU) defined a planet as: a celestial body that orbits around the sun; has sufficient mass to become round; and has "cleared the neighborhood around its orbit." On the strength of puny Pluto's inability to dominate nearby Neptune, whose orbit it crosses, as well as to clear out the Kuiper belt of many Pluto-size objects, it fails to qualify as a planet under the new definition.
Quote:
Originally posted by Scientific American.com
...some have noted that other planets fail to clear their neighborhoods as well: Jupiter moves in lockstep with thousands of Trojan asteroids and Earth hasn't exactly eliminated the possibility of being struck by one of many NEOs (near-Earth objects) lurking about its orbital track, notes Alan Stern, a planetary scientist at the Southwest Research Institute and principal investigator of NASA's recently launched New Horizons mission to Pluto. "I think it's embarrassing. Less than 5 percent of the world's astronomers voted in a split vote for a definition that is sloppy and technically incorrect," he complains. "In the end, this is the kind of definition that doesn't pass the smell test."