2005-08-02

What is a planet ?

The debate has been around since Copernic and before ...
The claim Friday that a 10th planet has been discovered in our solar system has set off a fresh round of debate and international talks aimed at defining the most vexing term in astronomy: the word planet.
Bottom line : The more you know about a subject, the trickier it is to define.

[2015-02-23] Just in case you were not aware of it, the follow-up of this story has been the redefinition of planet in 2006, by which Pluto is no more a planet, but a dwarf planet. A white horse is not a horse...