## Wednesday, August 16, 2006

### Prague assembly: there are 12 planets

The International Astronomical Union gathered here in Prague. What problems do the astronomers have? Do they have to face mentally challenged articles that astronomy is just a passing fad on a daily basis?

Your guess is right. The astronomers don't have any problems. So those 2,500 guys and ladies discussed whether Pluto is a planet. Yes, no, what of it? Nevertheless, the original proposal to downgrade Pluto has been killed. Instead, a broader definition of a planet was accepted:
• every object that has been brought into a spherical shape by its own gravity and that orbits around a star directly is called a planet.

With this definition, there are 12 planets in our Solar system. You can see Dennis Overbye's report for more details. In fact, Pluto's status as a planet was saved because of the astrologers. Initially, the global convention of astronomers denounced Pluto as a dirty chunk of meaningless space crap. But the Universal Association of Astrologers and Star-Gazers has condemned the move abruptly. See more information about this dirty political game here. ;-)

The new definition must be approved by a vote next Friday. Clearly, it won't solve everything. How spherical is spherical enough? If a moon is almost as large as a planet - or if you have a binary planet - will you count both of them as planets or none? At any rate, I am sometimes jealous about the jobs where they don't have any serious problems and they don't need any deep thoughts. On the other hand, it could become boring quickly.

Besides 9 planets that everyone knows, the new definition would upgrade the asteroid Ceres to the planet status, much like Pluton's Charon as well as a distant object called poetically "2003 UB313". Expect additional controversies.