(click to enlarge)

There is a possibility that the number of planets in our solar system will increase from 9 (or 8, depending on your position) to 12 next week. Will these 3 extra planets materialize from an extraordinary cosmic event, causing trillions of particles of space dust to rush together, pulling each other in towards three separate points of increasing gravitational force? Has a nearby supernova caused these planets to be released from their former star’s gravitational pull, only to be sent into orbit around our sun? No. These 3 planets will be created by a force far simpler than we can imagine, yet so powerful that it is virtually impossible for any one of us to escape its grasp. This force is none other than the media.

Next week, the International Astronomical Union will gather to vote on a proposed change in the definition of the term “planet”. The current definition states that a planet is a large accelerated mass, which is not a star or a moon, in orbit around a star. This very old definition leaves plenty of room for ambiguity, as the only thing separating non-planet bodies orbiting around stars, like asteroids, from planets is their relatively low mass. However, this leaves room for plenty of argument, especially in the case of Pluto. Because of Pluto’s very small size, many scientists have argued that it does not meet the criteria of “planethood”, and that it should be considered a non-planetary body like many others of similar size recently discovered. However, to eliminate any ambiguity in this matter, a new criterion has been proposed; in order to be considered a planet, a space body must not only meet the old definition, but also possess a certain degree of roundness caused by its own gravitational force. If this new definition is approved by the IAU, not only will Pluto be indisputably declared a planet, but three other bodies will join its ranks; Ceres, Charon and 2003 UB313. Ceres, previously considered to be the largest asteroid, will now be defined as the fifth planet from the sun, making it the outermost rocky planet, situated between Mars and Jupiter. Charon, currently considered to be a moon of Pluto will alternate between tenth and eleventh place, as Charon is not a normal moon; Pluto and Charon orbit each other, rather than Charon only orbiting Pluto. When Charon is on one side of Pluto, it will have the tenth position while Pluto has the eleventh, and vice versa. 2003 UB313, a recently discovered body slightly larger than Pluto, will take twelfth place as the outermost planet.

Right now, you may be thinking “I’ve been hearing all week in the news that there were going to be three new planets! These aren’t new at all, we’ve known about them for a long time!”. The media, in their never-ending quest to boost their audiences, have yet again spun a story full of hype, blowing it way out of proportion. They draw in the innocent masses, thrilled by the idea of a scientific breakthrough, enchanting them with promises of 3 new planets, withholding the truth for as long as possible, right until the very end of their story. Now that you’ve read this, you know the truth; you’ve escaped the powerful force of the media… at least for now. But how can you avoid being tricked again? Well, you can do what I do; check with the direct authority on the subject. Such sources include IUPAC for chemistry, IUPAP for physics, IAU for astronomy and IUBMB for biochemistry and molecular biology. You can also check your local library for copies of reputable scientific journals such as Science and Nature, but not magazines.

To see a map of the way the planets would be ordered if the new definition is passed next week, you can click the picture at the beginning of this post.

UPDATE: The outcome of the IAU’s meeting was highly unexpected. I have written a follow-up to this article.

(Image source: http://www.newscientistspace.com/data/images/ns/cms/dn9761/dn9761-2_800.jpg)

Works consulted:
The IAU draft definition of “planet” and “plutons”
Three new planets may join solar system

This entry was posted on Thursday, August 17th, 2006 at 6:48 pm and is filed under Astronomy/Space.