Yes, Pluto has been officially demoted. And rightly so. It’s a dwarf planet.
My understanding is that to be a fully-fledged planet you have to be massive enough to clean up pretty much all of the other lumps of rock in your orbit. To be a dwarf planet you have to be massive enough to collapse under your own gravity to form something more or less spherical in shape.
Pluto is a dwarf planet because its orbit is within the Kuiper belt (which is now known to contain other dwarf planets).
Dwarf planets I personally recommend are Eris and Ceres. (NASA has launched a probe that is scheduled to reach Ceres in 2015.)
Has Pluto been Offically demoted?
To what?
Yes, Pluto has been officially demoted. And rightly so. It’s a dwarf planet.
My understanding is that to be a fully-fledged planet you have to be massive enough to clean up pretty much all of the other lumps of rock in your orbit. To be a dwarf planet you have to be massive enough to collapse under your own gravity to form something more or less spherical in shape.
Pluto is a dwarf planet because its orbit is within the Kuiper belt (which is now known to contain other dwarf planets).
Dwarf planets I personally recommend are Eris and Ceres. (NASA has launched a probe that is scheduled to reach Ceres in 2015.)