Change the charts!

Perhaps some of you have been following the recent debates over whether or not Pluto is actually a planet. Apparently there has been some disagreement since its discovery in 1930, but the argument has gotten more intense recently since the discovery of a larger planetoid mass (named Xena) beyond it. Are Pluto and Xena really planets, or - because of their size and unusual orbits - Kuiper belt objects?

Well, don't worry, Pluto at least gets to keep its status as a planet, according to the new definition of planets that has been developed. Actually, I shouldn't say "new" definition, because there never really was a definition to begin with.

The converse of this is that certain objects not previously considered planets, such as the large asteroid Ceres, will now have "planet" status, as will a large number of other objects. Our old charts of the solar system are now out of date, it seems - and you can no longer use the mnemonics "My Very Elegant Mother Just Served Us Nine Pizzas" or the more popular "My Very Elegant Mother Just Sat Upon Nine Porcupines" to remember what all the planets are. Whatever we'll have to use instead will probably be insanely long.

The heated arguments that have been bandied back and forth with regards to whether or not Pluto is a planet may seem a bit silly, but in science, clarity and definitions are important. Remember we haven't always thought of the solar system the same way: the Greeks thought there were only five planets (Mercury, Venus, Mars, Jupiter, Saturn), which of course did not include Earth, and Ptolemy said they moved in loops through the sky. Later astronomers such as Tycho Brahe and Gallileo straightened that out, but the rest of the "standard" planets weren't discovered until later.

I wonder how long it will take for people to get used to all the new members of the "planet" club. I'd lay odds that there will be protests by non-scientist types against the inclusion of new planetary bodies - people will want the standard nine, just as they are. Problem is, if they want Pluto to be included as a planet, they have to include the new things as well. You can't have your cake and eat it too.

By the way, I'm taking the train home today and going to California tomorrow. Maybe I should try and find a list of all the "new" planets so I can remember them during the trip.

Update on the Planet Situation

So, apparently we now have twelve planets in our solar system: Ceres, formerly considered a large asteroid, residing between Earth and Jupiter; Charon, formerly considered to be a moon of Pluto but in truth engaged in a sort of roundabout with it; and Xena, out beyond Pluto.

Here's an article with a chart showing the new planets.

I hope they don't decide to add anything else before this settles down: I can remember three extra planets but too many more than that would be taxing.

Now...how do we develop a mnemonic device to remember these new planets? Especially since the last one starts with an X? Unless the mnemonic is based on Xena: Warrior Princess.