BBC地平线：拜拜冥王星 Bye Bye Planet Pluto (2006)认领

　　At its conference this August, the International Astronomical Union (IAU) will make a decision that could see Pluto lose its status as a planet. 　　For the first time, the organisation will be officially defining the word "planet", and it is causing much debate in the world of astronomy. 　　There is only one thing that everyone seems to agree on: there are no longer nine planets in t...