There was a lot of negative press and commentary about "demoting" Pluto from being a planet at the time. But its obviously true that it was the right move, and creating this "dwarf planet" class of objects was correct. It was hard to justify Pluto being a planet when Ceres exists, but Eris, Haumea, Makemake and all of these other possible Dwarf planets are the nail in the coffin.
> But its obviously true that it was the right move, and creating this "dwarf planet" class of objects was correct. It was hard to justify Pluto being a planet when Ceres exists, but Eris, Haumea, Makemake and all of these other possible Dwarf planets are the nail in the coffin.
I don't agree that "its obviously true that it was the right move". Instead of demoting Pluto, they could have promoted Ceres, and let Eris, Haumea, Makemake, etc, be planets too. Under that proposal, they could even have the category of "dwarf planets" encompassing them, it is just that "dwarf planet" would be a subcategory of planets rather than a disjoint category from them.
Yes. I wouldn't call a dwarf person any less of a person, nor would i refer to a dwarf planet as being any less a planet. Between the terrestrial planets, the gas giants, the ice giants, and arguably a couple of rounder moons, we have far more than 50 planets in our solar system.
By some extreme definitions, Earth might not be a planet. Some say the moon is too big to qualify the earth "cleared out its orbit" criteria, making Earth-moon some sort of double planet... like Pluto-Charon.
Setting aside the whole "demote Pluto" and "dwarf planet" aspects, I find it amusing that we use the same term for small rocky Mercury (2,440 km radius, 5% of Earth's mass) and immense gaseous Jupiter (69,000 km radius, over 300 times Earth's mass). Only we don't, of course. Jupiter is a gas giant, while Mercury is a rocky planet, or iron planet; there's a lot of 'planet' terminology.
Ultimately these sorts of quibbles are fundamentally semantic in nature thus (in general) entirely pointless. It's only the subjects themselves - the myriad celestial bodies - that are interesting.
Why is Jupiter in the same category as planets then?
Jupiter does not orbit the sun (the first requirement per IAU definition of planet), the barycenter for the system is not inside the surface of Sol at 1.07 solar radius.
It is not planet then yes ? There is no push to promote it to a sub-brown dwarf or a new category .
Classifications are always arbitrary and only fits some bias one way or other.
I initially assumed from your comment that all of those objects are larger than Pluto, but none of them are, so what exactly is "obvious" about the decision? They haven't resolved any inconsistency by demoting it.
Ceres by itself doesn't really challenge Pluto's old classification. Pluto has 14 times the mass of Ceres, and five moons. Ceres is the only "dwarf planet" classified so far that has zero moons. There are still good arguments for a definition that doesn't consider Ceres a dwarf planet.
This helps illustrate how arbitrary these classifications are. They depend entirely on what properties are included in the definition. The updated IAU definition is essentially reverse engineered to fit how they wanted to classify the planets.
So, a factor of 14.4 is enough to put the line between Ceres and Pluto, but a factor of 23.0 is not enough to put it between Pluto and Mercury?
Yes, those classifications are arbitrary, but then any classification is. If you want to consider Pluto as a planet, you have to include quite a lot of other bodies, which are all qualitatively and quantitatively different from the 8 (which themselves are in 2 qualitatively and quantitatively different groups. Or 3, depending on who you ask).
In the grand scheme of things, it does not matter and astronomers won’t care about the general public’s feelings. It is utterly pointless to get worked up about these things.
> The new dwarf planet candidate, called 2026 ED138, orbits on a plane tiled nearly 25 degrees
I've noticed similar glaring typos in 2 recent articles. In both cases very early in the article. Is it possible that they are adding typos intentionally to mask the AI authoring?
(This uses wasm, meant for a desktop, and will download the asteroid catalog of about 65mb, you have been warned)
https://dahlend.github.io/ketev/#t=2009-07-01.717&sel=2026%2...
This is a big boy.
I don't agree that "its obviously true that it was the right move". Instead of demoting Pluto, they could have promoted Ceres, and let Eris, Haumea, Makemake, etc, be planets too. Under that proposal, they could even have the category of "dwarf planets" encompassing them, it is just that "dwarf planet" would be a subcategory of planets rather than a disjoint category from them.
I find people do this a lot with space stuff because they're interested in it but don't really know much about it.
It's ultimately irrelevant to the subject at hand and detracts from the conversation.
https://en.wikipedia.org/wiki/Law_of_triviality
https://en.wikipedia.org/wiki/Lumpers_and_splitters
By some extreme definitions, Earth might not be a planet. Some say the moon is too big to qualify the earth "cleared out its orbit" criteria, making Earth-moon some sort of double planet... like Pluto-Charon.
https://en.wikipedia.org/wiki/List_of_planet_types
Jupiter does not orbit the sun (the first requirement per IAU definition of planet), the barycenter for the system is not inside the surface of Sol at 1.07 solar radius.
It is not planet then yes ? There is no push to promote it to a sub-brown dwarf or a new category .
Classifications are always arbitrary and only fits some bias one way or other.
This helps illustrate how arbitrary these classifications are. They depend entirely on what properties are included in the definition. The updated IAU definition is essentially reverse engineered to fit how they wanted to classify the planets.
Yes, those classifications are arbitrary, but then any classification is. If you want to consider Pluto as a planet, you have to include quite a lot of other bodies, which are all qualitatively and quantitatively different from the 8 (which themselves are in 2 qualitatively and quantitatively different groups. Or 3, depending on who you ask).
In the grand scheme of things, it does not matter and astronomers won’t care about the general public’s feelings. It is utterly pointless to get worked up about these things.
Pretty rad.
I've noticed similar glaring typos in 2 recent articles. In both cases very early in the article. Is it possible that they are adding typos intentionally to mask the AI authoring?
https://en.wikipedia.org/wiki/Planets_beyond_Neptune