"pluto is dead." read here.
as of today, there are only 8 planets in our system. pluto is now considered to be a dwarf planet.
changes. sometimes these sort of changes make one look at things from a slightly different perspective. but if you really think about it, nothing's changed but the people's definition of a thing. the "object" is still there, circling its merry way around the sun, not really caring if we call it a planet or not. we're just picky about these things, i guess.
one of these days our definition of time will change from 60 seconds for a single minute to a decimal system where one minute will take a hundred seconds. time himself will not really care. but we will. we're picky.
there are more changes coming and all one can do is have an open mind.