Prague is the setting for the International Astronomical Union conference that will mull, over 12 days, the definition of a planet.
Planet is a greek word translating to ‘wanderer’ as the planets were first noticed as stars that moves around in the sky. Modern science more recently made a planet something much more vague: a body that orbits a star and which isn’t a star itself… or a comet… or an asteroid. We also have brown dwarfs, bodies that are star-like but not planets and maybe even planet like objects that form without a star anywhere nearby! The long and short of it is that the definition of ‘planet’ needs sorting out.
Pluto has been a source of discussion recently since although historically regarded as a planet the small two-body system of Pluto and its moon Charon, isn’t really anything like the other planets in our Solar System. It has a highly elliptical orbit and is extremely small.
Last year when the so-called tenth planet was discovered Pluto’s status as a planet was really thrown into doubt as it was a similarly located but possibly larger world which was also located near the Kuiper Belt (a large extend of debris at Pluto’s distance, much like the Asteroid Belt found between Mars and Jupiter). Astronomers now believe there may be many worlds like Pluto out there in the Kuiper Belt amongst small, less recognisable bodies. So which are planets and which are not and why should Pluto be considered so special?
This has all gathered momentum to this conference at which the IAU hopes to define exactly what a planet is and therefore whether Pluto will remain under its current classification. One option is that it will no longer be thought of as a planet. Another is that the object discovered last year will become the official tenth planet. If the latter is true then we may be able to expect a whole host of new planets over the next few years.
The conference is expected to take about 12 days so I will be reporting on Pluto’s fate in due course and we shall see whether Sedna, Xena, and other recently discovered worlds will be joining the ranks of the planets in the minds of future generations.
Personally I’m hoping for more official planets but I have a feeling Pluto will be bumped off into history. If it does then I feel we ought to be sad since Pluto has no doubt fired a lot of imagination over the past almost eighty years since its discovery. And what will the amazing My Very Easy Method Just Speeds Up Naming Planets pnemonic?
