Posted by cybermango 4 hours ago
(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.
You can also turn on the known asteroid population:
https://dahlend.github.io/ketev/#t=2026-11-12.9717&sel=2026%...
Everything runs in the browser, served as a static github pages so I don't have to think about hosting or anything.
but it's not great for mobile
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.
Classifications impose structure on a collection of celestial objects, and we can derive relationships, commonalities, understand their development, the physics governing these objects, and build useful physical and mathematical models to widen our understanding of the universe.
Most reasonable scientists understand that some of these objects will blur the edges—like many moons being more massive and larger than Mercury. Or like the largest super-Earth exoplanets being nearly as massive as Neptune, or the largest gas giant exoplanets being 30-80 times as massive as Jupiter and hence having a surface temperature of ~2000 K. But that is part of science, and possibly even where the most interesting work is.
It very much seems like the definition was just shoe-horned to stem any more planets needing to be added. It would be interesting to know if astronomers walk the walk when it comes the definition. If I research when planets were formed would I get the date when their neighborhoods were cleared? Do discussions around large events that send debris into the neighborhood of planets correctly reflect that they cease to be planets until it is cleared?
Alan Stern said it best
>"We're going to call it a cow, except when it's in a herd." A river is a river, independent of whether there are other rivers nearby. In science, we call things what they are based on their attributes, not what they're next to.
>And the IAU definition is even worse, because it produces different categorizations for identical objects, depending on where they are. Get this — Earth at the same distance from the sun [as Pluto] would not be a planet by the IAU’s measure, because Earth can’t clear that zone either. I would say any definition that produces a result where Earth is not a planet under any circumstance is immediately indicted as ridiculous, because one thing we all agree is a planet is planet Earth!
>That's crazy. No wonder teachers and students are frustrated, confused, unhappy. It reflects poorly on astronomy, to have something so illogical.
https://www.space.com/12710-pluto-defender-alan-stern-dwarf-...
Now, Stern's broader argument in that interview is that we should not take into account the dynamical behaviour of planets. I disagree, especially since dynamics determine the static future state of any given object. Take chthonian planets—former gas giants whose gaseous envelopes have been stripped away by the primary. Do we insist that they are still gas giants? No, we even came up with a name for the transitory period when these planets are losing their gas envelopes.
Personally, I think Stern was being a little more animated to drum up support for and shine a beacon on New Horizons, a then-ongoing mission that he was principal investigator of.
To directly answer your question:
> If a massive object came into the solar system and perturbed orbits, caused chaos and collisions, then any "planet" with debris within its neighborhood would cease to be a planet.
There actually are (multiple) mathematical formulations for 'clearing the neighbourhood'[2]; it's not purely empirical or based on vibes. Stern proposed one in the above-mentioned paper. Jean-Luc Margot suggests several more[3]. I suspect a more universal model will be probabilistic but grounded in celestial mechanics.
> Does it realistically outweigh decades or centuries of peoples intuition of the existing definition?
People's intuition for 'planet' in the centuries before telescopes were invented was 'something that moves against the fixed background of stars'—that is literally the Greek etymon for the English 'planet'. The Sun and Moon used to be a part of the 'classical planets'. We didn't even find the last two (or three) planets in our own Solar System until around two centuries ago. We didn't know about nuclear fusion until 1925, and we didn't know other galaxies existed until similarly recently. We didn't understand the inflationary model of the universe until the 1960s. The first exoplanet was discovered only in 1992.
We have repeatedly and retroactively renamed, retconned, reworked, revamped and rewound scientific definitions and models over and over again. I think planets will be OK.
[1]: https://doi.org/10.1017/S1539299600013289
[2]: https://en.wikipedia.org/wiki/Clearing_the_neighbourhood
It's clear that they worked backwards from the eight planets to come up with a classification system that fit, but in realizing the problems with the approach, just gave up and created the carve-out.
Also, just as another example of the absurdity of the IAU definition, there's a pretty strong argument to be made that Earth's moon would be a planet under the criteria: it orbits the sun, it's round, and it's massive enough / positioned such that it's capable of clearing its neighborhood.
Is this classification useful for everyday life? Not at all, but looking at things from different perspectives for a change can be quite amusing.
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.
Just expect to be corrected and "well, achually"-ed by people who follow the current naming system, especially in science circles.
With such “well, ackshually”s as “you didn’t really do any work at all when you were pushing on that tree trunk” and “you specified watts, but you really wanted to use lumens”.
My Very Elegant Mother Just Served Us Nachos
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.
If they really didn't want people to continue to refer to them as planets, then they should have chosen a completely different noun.
Like, in high fantasy, right, we have humans and elves and dwarves and orcs and all that. Are dwarves 'less' than elves? Are orcs 'less' than humans? No, they exist on a spectrum or line that is not less or more. Maybe less or more evil, maybe less or more aged or fancy. But in high fantasy you can't demote a elf to be a dwarf or a human into an orc. |
So, my proposal: Include all the dwarf planets in all the science exhibits, the kindergarten posters, the rhymes and meters. Just like with the upper and lower cases of the Latin alphabet. Sure you can forget that the dwarf ones exist, but if it's on everything, then that'll be hard.
Here's a quick one that I put like no thought into:
>Mercury, Venus, here comes Earth!
>Mars is next, let's shout with mirth!
>Jupiter's big, Saturn has rings,
>Uranus and Neptune make eight amazing things!
>Ceres, Pluto, Haumea too!
>Makemake and Eris join the crew!
>Sedna, Quaoar, Orcus, Gonggong,
>Dwarf planet dancing all day long!
So, again, sure, dwarves, fine. But just don't make being a dwarf planet a 'thing', celebrate them too!
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.
a) orbits a star, and is not a star nor a brown dwarf itself;
i) a star is an object that is massive enough and hot enough to conduct protium fusion in its core
ii) a brown dwarf is an object that is massive enough to conduct deuterium fusion, but insufficiently massive (and hence insufficiently hot) for protium fusion
b) has attained hydrostatic equilibrium, that is, it is spheroidal;
c) it has cleared its local neighbourhood of 'rival planets' since its birth;
There is some controversy about when giant planets stop being giant planets and start being brown dwarfs—typically around 30 Jupiter masses—but this is an active area of research, to understand the fusion ignition in these objects. As I mentioned in another comment, classifications are useful. Of course they are arbitrary and they are biased—they were decided by humans. But the entire point of science is to push the edges of our understanding and reduce these biases and make our models more general and less arbitrary.
There is no academic literature or accepted consensus barycenter has to be orders of magnitude away - the accepted consensus is that a body orbiting another means internal barycenter, if they have external barycenter then they orbit each other period.
The fact that Charon and Pluto do not have internal barycenter is why Pluto-Charon (also Eris-Dysonmia) are considered dwarf planet systems ; and that was used partly in support (while not used in definition) of arguing for dwarf status of Pluto .
Thus the suggestion for a new dwarf category — precisely because we do label times the barycenter is outside the star differently, as you yourself note.
You were so busy trying to “correct” me, you failed to address the topic.
The topic is pointless hair-splitting and nostalgia. It's like saying we can't ever use F = ma to describe free-body diagrams; we need a full relativistic per-particle QFT simulation to accurately and precisely model every single interation. That is impractical, at least for now. Likewise, we come up with classifications that are useful for the present time. If 'dwarf planet' is a catch all for all the small roundish bodies in our planetary system, then so be it. I suspect the IAU will make things more fine grained in the relatively near future. We even classify the asteroids as more than just rocky lumps.
We can similarly say that “cold dwarf binary systems behave similarly to planetary systems, due to the proximity of the barycenter to the star”.
And that’s more informative than calling Jupiter a planet.
Don't forget about Gǃkúnǁʼhòmdímà! Everyone forgets about Gǃkúnǁʼhòmdímà.
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.
Why not? It's an arbitrary line, and there has to be a lower limit somewhere.
In the IAU definition, hydrostatic equilibrium loosely defines a lower limit for all planets including dwarf planets, but at the limits that's a fuzzy property that gets debated for small bodies. In fact Ceres is less massive than what some studies have found to be required for hydrostatic equilibrium, e.g.: https://iopscience.iop.org/article/10.3847/PSJ/ad55f3 . The abstract of that paper starts out with, "The current IAU definition of 'planet' is problematic because it is vague and excludes exoplanets."
If we had more small planetary candidates in the solar system, they would have had to come up with some additional constraint to separate planets from non-planets.
I wholeheartedly agree with this take. I have something of a personal hatred of poorly executed retconning thus I present the following proposal.
For the sake of simplicity we should use even powers of 10 with earth as the primary reference point. Note that the earth is 10^24, mars is 10^23, and the earth's moon is 10^22 (pluto is also 10^22 and less massive than the earth's moon). It seems "obvious" then that 23-25 are planets, 22 or less are relegated to dwarfs, and 26 and over are giants (jupiter is a 27 and the sun a 30 for reference).
By that logic, if we want to consider pluto a planet then the earth's moon also has to qualify. I don't really care one way or the other but that just doesn't seem sensible to me.
We've barely confirmed the existence of 10_000 exoplanets in our galaxy, and the methods we use to detect them are heavily biased toward certain ranges of planetary mass and orbital distance
As far as we know, everyone could very well be right here
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?
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