Pluto should be a planet again, or never should have not been a planet, scientists say, again. Scientists keep saying this; it’s good for a news hit, especially among the outraged traditionalists in the general public who grew up on nine planets and never bought the excuses for taking the last one away. When you learn a thing in school, a basic fact like the number of planets and what they are, you don’t want it reversed on you later.
Pluto is the same thing it ever was. The controversy is never about the facts about Pluto. This particular version of the controversy is about whether the standard by which Pluto was demoted from planet-hood, its inability to clear its orbit of other objects, shows any historic record of having been a standard used by scientists in their definitions of planets, before it was used to define Pluto out.
Pluto got forced out not because astronomers truly did or did not care about how thoroughly an object clears its orbit, but because astronomers had a problem. They had learned more about other objects in the Solar System, and lost confidence in their own judgment. If Pluto was a planet, then why wasn’t Ceres, previously known as the largest asteroid in the asteroid belt, but just as rounded, planet-style, as Pluto? Or, worse yet, Eris? They found that one in 2005, way out past Pluto’s orbit, nearly the same size as the official last planet and more massive than it.
If Pluto was a planet, then Eris would have to be a planet, and if Eris got in, how many other round balls of rock would come crowding in after it through the conceptual breach, till the whole orderly Solar System turned into a shitshow like the moons of Jupiter, which went from Galileo’s four up to a dozen by the time I was born, and are now up to 79 on Wikipedia, not to mention all the rings? So Pluto, through no fault of its own, got demoted to dwarf planet.
None of this matters to the planets. Someday, in the orbital network around Jupiter, the Europans will swim up to the surface of the ice and poke their telescopes through and they will declare that the Solar System contains four planets: large bodies with thick gassy atmospheres, capable of holding multiple large moons in orbit around themselves. Scattered here and there among the true gas planets will be minor rocky bodies, ranging in size from the big asteroids up to the largest of the spheres, between Mars and Venus: a hot one, with a thin veil of nitrogen and carbon dioxide over it, and lifeless acidic seas of water, but otherwise as dead and uninteresting as all the others.