Hey, if we find something bigger than Pluto, then by all means let’s call it a planet.
By any reasonable person’s definition of a planet, Pluto is a planet. It’s a rocky spherical mass that orbits the sun, with a varied terrain of mountains, plains and glaciers. It has days and seasons. It has its own system of moons.
An additional grievance I have is that, by the IAU’s stupid definition of a Dwarf Planet, Charon should really be called a dwarf planet too. It isn’t a satellite of Pluto in a meaningful sense - both Pluto and Charon orbit a point between them. The other moons also orbit this space between Charon and Pluto.
So, want to know why it isn’t a Dwarf Planet? Because the IAU class it as a planetary satellite. What’s the formal definition of a planetary satellite then? There isn’t one. It was discussed, but a formal definition was not decided upon. Charon is literally a moon now because it was called a moon before the definition of a planet was changed and dwarf planets were invented.
I’m all for formal definitions, but the IAUs current rules are just really sloppy. It’s maddening.
You’re not wrong, but I’ve also seen people calling Pluto-Charon binary dwarf planets.
But yes, the IAU tends to only pin down definitions when one is becoming unworkable - in this case the ever larger numbers of trans-Neptune objects that were potential planets.
Hey, if we find something bigger than Pluto, then by all means let’s call it a planet.
By any reasonable person’s definition of a planet, Pluto is a planet. It’s a rocky spherical mass that orbits the sun, with a varied terrain of mountains, plains and glaciers. It has days and seasons. It has its own system of moons.
An additional grievance I have is that, by the IAU’s stupid definition of a Dwarf Planet, Charon should really be called a dwarf planet too. It isn’t a satellite of Pluto in a meaningful sense - both Pluto and Charon orbit a point between them. The other moons also orbit this space between Charon and Pluto.
So, want to know why it isn’t a Dwarf Planet? Because the IAU class it as a planetary satellite. What’s the formal definition of a planetary satellite then? There isn’t one. It was discussed, but a formal definition was not decided upon. Charon is literally a moon now because it was called a moon before the definition of a planet was changed and dwarf planets were invented.
I’m all for formal definitions, but the IAUs current rules are just really sloppy. It’s maddening.
You’re not wrong, but I’ve also seen people calling Pluto-Charon binary dwarf planets.
But yes, the IAU tends to only pin down definitions when one is becoming unworkable - in this case the ever larger numbers of trans-Neptune objects that were potential planets.