I'm not that bothered by the fact there are only 8 planets but I feel sorry for all the writers of science text books and teachers as all their materials will be wrong
I've never really understood what makes a planet a planet rather than just a big rock in space. The thing that makes me curious is what would they do if they ever discovered evidence of life on these 'rocks'. Would they then be classed as a planet or just a rock with life on it?
I can understand classifying rocks as moons if they orbit a planet, but how do they decide if something that orbits a star is actually a planet? It must be a pretty hard thing to classify.