There are serious issues with the vote taken by the International Astronomical Union to demote Pluto to a “dwarf planet,” according to the BBC. The controversy may only be heating up.
The crucial criterion adopted is that a planet must have cleared the space in its orbit. “If Neptune had cleared its zone, Pluto wouldn’t be there,” said Dr. Alan Stern, who leads the US space agency’s New Horizons mission to Pluto. Stern points out that a small minority of astronomers remained in Prague for the final vote and “that Earth, Mars, Jupiter and Neptune have also not fully cleared their orbital zones. Earth orbits with 10,000 near-Earth asteroids. Jupiter, meanwhile, is accompanied by 100,000 Trojan asteroids on its orbital path.”
My feeling is that Pluto doesn’t make the grade. If Pluto is a planet, then “[b]y the end of the decade, we would have had 100 planets, and I think people would have said ‘my goodness, what a mess they made back in 2006’,” said Professor Iwan Williams, the IAU’s president of planetary systems science.
The real issue here is whether planets should be seen as somehow special and granted some form of exalted status. If they should, then Pluto probably shouldn’t be a planet. But if the whole idea is just pathetically oversimplistic, then perhaps we should ditch the current concept of planets altogether. It may be that like race–academically accepted as a social rather than a biological concept–the idea of planets can never be satisfactorily defined.