New definition of planet


The nine planets of the solar system are about to be transformed into 12.

At one point it was thought that Pluto - the smallest and most distant of the planets - would be kicked out of the club, but now it appears that it is welcomed as the prototype of a new class of smaller planets known as "plutons".

" The three new planets are Charon, once considered a moon of Pluto but now described as its double planet; Ceres, formerly known as an asteroid or minor planet; and UB313, an object that has yet to be given a formal name (although it has been nicknamed Xena), and which was only identified last year.

There are now eight "classical" planets, three "plutons", those planets that are similar in size to Pluto withextremely wide solar orbits, and theasteroid-like Ceres.

IAU's planet definition committee concluded that in future a planet should be defined as a celestial body that is big enough for its gravity field to form a near-spherical shape.

The object must also be in orbit around the Sun - or another star - but not as a satellite of another planet, which rules out the Moon and the larger moons of other planets.

The new definition of a planet means that there are another dozen or two dozen other known objects in the solar system that may one day be included in the planetary club.

The seven-member definition committee convened in Paris in late June and early July, and its recommendations will now go to the IAU's general assembly which will vote on the resolution as its meeting in Prague this week.


The Pluto-Charon sytem will now be called a doube planet.
I really don't understand the use of this new categorization. Yes, the old ones were faulty, and either de-classified Pluto or classified everything spherical including Earth's moon - but the new one ist not much better, mere window-dressing. For the former transjovian bodies we now have the "plutons", and Ceres' promotion seems unmotivated to me.
What's the point? Raise interest in space? Raise the funding for space programs? Have thicker schoolbooks?
There was more action on this today, and it went in a decidedly unexpected direction:

Pluto Is Demoted to ‘Dwarf Planet’

After years of wrangling and a week of bitter debate, astronomers voted on a sweeping reclassification of the solar system. In what many of them described as a triumph of science over sentiment, Pluto was demoted to the status of a “dwarf planet.”

For now, the dwarf planets include, besides Pluto, Ceres, the largest asteroid, and an object known as UB 313, nicknamed Xena, that is larger than Pluto and, like it, orbits out beyond Neptune in a zone of icy debris known as the Kuiper Belt. But there are dozens more potential dwarf-planets known in that zone, planetary scientists say, and the number in that category could quickly swell.

The vote completed a stunning turnaround from only a week ago when the assembled astronomers had been presented with a proposal that would included 12 planets, including Pluto, Ceres, Xena and even Pluto’s moon Charon. Dr. Boss said today’s decision spoke to the integrity of the planet-defining process. “The officers were willing to change their resolution and find something that would stand up under the highest scientific scrutiny and be approved,” he said.

Check out the article.
Now the whole education system will have to revise through the current textbooks because of this.

Today, on the news one scientest pitted the meaning for Pluto's own demotion from its previous state with planets;

"...We are trying to distinguish the difference between planets and the rubbles found in the universe, and unfortunatley for poor old Pluto, its just a rubble".

Damn them!
I like how angry this news makes everyone (in contrast to how it has absolutely no effect whatsoever on our lives).
People don't like change, no matter how (Pegos) minor.