The problem is with Jupiter not Pluto

(Picture credit:IAU-Martin Kornmesser)




Lord Raleigh is supposed to have said "Physics is the only science, all the rest is stamp collecting". This normally not-to-be-taken-seriously type of remark seems to apply to the august gathering (oh! there's a pun here) of the members of IAU in Prague whose sole purpose -or so it seems- is to classify the bodies in our solar system as planets or non-planets.

One camp wants to promote Ceres (currently an asteroid but which used to be a planet in 19th century) , the newly discovered UB313 (a.k.a. Xena) and Pluto's moon Charon to the status of planets. The other camp would like to demote Pluto and lump it with these three bodies and call them all dwarf planets.

Meanwhile there is real long standing question about planets which remains unanswered. It is known that Jupiter emits 70% more light than what it gets from the sun.
What is the source of this energy? A gasseous planet must have minimum mass of 1.8 times Jupiter's mass before the hydrogen fusion can take place in its core (the planet then turns into a star). So where does Jupiter get this excess energy since it is too puny to be a star? Thats a real physics question.

The news from the IAU gathering is that the division between the two camps is right down the midddle and the issue will be settled by votes later today and Pluto's fate hangs by a thread.
Yawn...