On 30 April 2015 at 12:37, Thomas Douillard thomas.douillard@gmail.com wrote:
Infovarius even complicated the problem, he put the number of "known" planets at some time with a qualifier for validity :)
Just to throw a real spanner in the works: for a lot of the nineteenth century the number varied widely. The "eighth planet" was discovered in 1801, and is what we'd now think of as the asteroid or dwarf planet Ceres; the "real" eighth planet, Neptune, wasn't discovered until 1851.
Newly discovered asteroids were thought of as 'planets' for some time (I have an 1843 schoolbook somewhere that confidently tells children there were eleven planets...) until by about 1850, it became clear that having twenty or so very small planets with more discovered every year was confusing, and the meaning of the word shifted. There was no formal agreement (as was the case in 2006) so no specific end date.
The moral of this story is probably that trying to express complex things in Wikidata is not always practical :-)