Pluto is not a planet. Get over it. While there is some ambiguity in the definition of planet especially in the middle, there is little ambiguity at the extremes of the definition. Pluto is way out there. We were wrong to call it a planet. Now we know better. Let it go people. This is science. We correct science when it is shown to be wrong, unlike some other things.
Did you know that Jupiter could have been a star? Only needed to be a little bigger!
From Tech Republic:
If someone were to ask you to name the ninth largest object that directly orbits our sun, odds are you would respond with Pluto. After all, even if you can’t call Pluto a planet anymore, it’s still the ninth biggest rock in the local solar neighborhood, right? Actually, no. The ninth biggest rock directly orbiting the sun is Eris, a dwarf planet named for the Greek goddess of discord. Considering how much disagreement was engendered by the discovery of Eris and her sibling dwarf planets, there’s probably no better mythological namesake for this local celestial object.
You see, lots of folks are still bent out of shape that Pluto was demoted from actual planet to dwarf planet. Fan though I am of that most famous of trans-Neptunian objects, Pluto’s claim to planethood was shaky at best. Besides being outsized by Eris, Pluto is actually smaller than seven moons in the local solar system. Its orbit is rather eccentric, slipping occasionally closer to the sun than Neptune before swinging further away again. In fact, Pluto was in many respects considered a planet simply because it was found during Percival Lowell’s attempts to locate the mythical Planet X beyond Neptune, and because initial estimates of its size were far larger than Pluto’s true mass. Put another way, Pluto earned planet status mostly because it was found at the right time and by the right people, who made the right mass-estimate mistakes.
Still, some argue that because Pluto was considered a planet for so long — more than 75 years — it should be grandfathered into the planet club. That notion breaks down when you cite the Ceres precedent. Asteroid Ceres was listed as a planet for more than 50 years, mostly because no one knew what else to call it. Ceres led directly to the coining of the term asteroid to describe sub-planetary rocks of significant size, a title it inherited once it was stricken from the roster of planets. Because of Eris, Pluto went through the same it’s-not-really-a-planet-so-let’s-invent-a-new-category process, giving us dwarf planets.