[Update1…. Oh no it’s not official! See here.] [Update2: The vote is in… see here.] [Update3: (7th June 2010) Moved the updates 1 and 2 one sentence earlier since, bizarrely, some readers (ahem! you know who you are…) don’t seem to read further than one sentence, or check the posting date, before entering their findings into their homework.] It’s official!* There are twelve planets in our Solar System (so update all the posters, such as the ESA one on the right).
- 2003 UB313
In addition, you’ll have to add a new word or two to your vocabulary, such as “pluton”, of which Pluto is the prototype. From the 16th August press release of the International Astronomical Union:
16-August-2006, Prague. The worldâ€™s astronomers, under the auspices of the International Astronomical Union (IAU), have concluded two years of work defining the difference between â€œplanetsâ€ and the smaller â€œsolar system bodiesâ€ such as comets and asteroids. If the definition is approved by the astronomers gathered 14-25 August 2006 at the IAU General Assembly in Prague, our Solar System will include 12 planets, with more to come: eight classical planets that dominate the system, three planets in a new and growing category of â€œplutonsâ€ â€“ Pluto-like objects â€“ and Ceres. Pluto remains a planet and is the prototype for the new category of â€œplutons.â€
(*almost official. It has to be approved, it says.)