Back in 2006, Pluto, until then the 9th planet of the solar system, was officially considered by astronomers as a "dwarf planet", and no longer a whole planet, like Earth, Mars or Venus.
quoting http://www.msnbc.msn.com/id/14489259/:
"Capping years of intense debate, astronomers resolved to demote Pluto in a wholesale redefinition of planethood that is being billed as a victory of scientific reasoning over historic and cultural influences. But the decision is already being hotly debated.
Officially, Pluto is no longer a planet.
'Pluto is dead', said Mike Brown, a planetary scientist at the California Institute of Technology who spoke with reporters via a teleconference while monitoring the vote. The decision also means a Pluto-sized object that Brown discovered will not be called a planet. "
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Pluto is also the name of a famous dog in planet Earth.
