The trouble with "dwarf planets"
The trouble with the current planet definition controversy started out being that what some astronomers really wanted was a size restriction on what constituted a planet... a restriction that was clearly non-scientific and arbitrary. Pluto's not big enough, they kept saying, to really be called a planet. After all, it's only x% the size of Mercury..., it's smaller than some moons... However, the fact that this was a clearly arbitrary designation was plain to everyone. But the reality of this measurement--that size is really what matters--remains in the lesser defintion of "dwarf planet".
The trouble with the controversy now, is that "dwarf planets" are not really put into that category because they are small. Rather, a definition was jury-rigged that was slightly more scientific, but which had nothing actually to do with size. Yet the term "dwarf" remains because of this fixation on whether or not Pluto belongs to the glorious category of "planet".
Yet objects in the Kuiper Belt are expected to be possibly the size of Mars. And yet because of the new definition will be called "dwarf planets" even though they are significantly larger than "real" planets.
This doesn't make any sense.
Furthermore, there is no standard for the definition that has been proposed for this lesser category, regardless of what you call it. What is the size of the neighborhood that a planet must sweep up to be considered for planet status? How clear must that neighborhood be? What percentage of the mass in the neighborhood is enough? Since Pluto crosses the orbit of Neptune, it's said be to excluded, but the fact is that Pluto and Neptune orbit in such a way that they are never in the same place at the same time... they don't actually interact.
Many questions remain unresolved. The definition is shockingly unscientific in my view. I don't understand the logic behind the argument that if we chose the original proposal, and ended up with several dozen planets, that school children would be obliged to memorize them all. I mean, seriously, I didn't even have to memorize all the US States in school. Nor do I understand the logic behind the idea that it's bad if the Earth's Moon might someday become a real double planet as it continues to pull away from the Earth. It's bigger than Pluto, isn't it?
And if it isn't completely clear by now, until I get a coherent definition I can live with, a planet is just going to be the original simple definition proposed by the IAU committee... a round object which orbits the sun.
The trouble with the controversy now, is that "dwarf planets" are not really put into that category because they are small. Rather, a definition was jury-rigged that was slightly more scientific, but which had nothing actually to do with size. Yet the term "dwarf" remains because of this fixation on whether or not Pluto belongs to the glorious category of "planet".
Yet objects in the Kuiper Belt are expected to be possibly the size of Mars. And yet because of the new definition will be called "dwarf planets" even though they are significantly larger than "real" planets.
This doesn't make any sense.
Furthermore, there is no standard for the definition that has been proposed for this lesser category, regardless of what you call it. What is the size of the neighborhood that a planet must sweep up to be considered for planet status? How clear must that neighborhood be? What percentage of the mass in the neighborhood is enough? Since Pluto crosses the orbit of Neptune, it's said be to excluded, but the fact is that Pluto and Neptune orbit in such a way that they are never in the same place at the same time... they don't actually interact.
Many questions remain unresolved. The definition is shockingly unscientific in my view. I don't understand the logic behind the argument that if we chose the original proposal, and ended up with several dozen planets, that school children would be obliged to memorize them all. I mean, seriously, I didn't even have to memorize all the US States in school. Nor do I understand the logic behind the idea that it's bad if the Earth's Moon might someday become a real double planet as it continues to pull away from the Earth. It's bigger than Pluto, isn't it?
And if it isn't completely clear by now, until I get a coherent definition I can live with, a planet is just going to be the original simple definition proposed by the IAU committee... a round object which orbits the sun.