How many planets are there in our solar system? Say nine and be prepared to blush like me! Well, I grew up memorizing their names, not very well I will say, even now I sometimes miss one or two when I am not writing down the names on a paper, just doing the mental counting. Good news for those who count less than nine, well, as per a summit in 2006 our solar system no longer counts Pluto as a planet, it has been demoted to a dwarf planet.
They fixed three rules, Pluto fits two of them, it orbits around sun and it is spherical, but flunks the third rule, it is a fraction of the icy debris in its orbit, whereas planets have to account for the debris or other particles in its orbit.
So our solar system has eight planets and five dwarf planets. Mercury, Venus, earth, mars, Jupiter, Saturn, Uranus, Neptune are the planets, and Pluto, Ceres, Haumea, Makemake and Eris.
The world is ever changing, eh?