Since it was stripped of planetary status, Pluto’s defenders have been fighting
theguardian.com
theguardian.com
No, there is no flaw in this, and moreover there is nothing new in this. This is how it has always been, it is not something invented recently.
In the Solar System, there are 3 Mercury-sized satellites and other 3 Moon-sized satellites, besides the Moon. If they had not been in their orbits as satellites, they might have very well been planets. Therefore the old definition of "planet" also depended on the orbit of the body, not only on the size and shape of the body.
Most of those satellites are bigger than Pluto. Triton, the biggest satellite of Neptune, had been in the distant past another planet with an orbit close to Pluto, but it was captured by Neptune and it has become a satellite. Otherwise it would have remained a "dwarf planet", orbiting close to Pluto. So Triton was demoted from "planet" to "satellite", by Nature, not by a human organization.
The current definition of "planets" and "dwarf planets" is fine.
If anything, there are too few planet classes, not too many. A more useful classification is into big planets, medium planets and small or dwarf planets, where the Solar system has 4 big planets, 4 medium planets, and a lot of small planets.
The big planets, i.e. which are big enough to retain the volatile chemical elements, like hydrogen and noble gases, not only the refractory elements, have a very different chemical composition from the medium planets, and this difference will also exist in any other stellar system that has condensed from gases like those at the origin of the Solar System, with more oxygen than carbon (there exists the possibility of stellar systems with a different chemical composition than the Solar System, formed by condensing from gas mixtures with more carbon than oxygen).
- a gang of dwarfs
- some rocky ones
- and gas giants
- and one star to rule them all
As I understand it, in fact, there was discussion about defining systems like Earth-Moon as double planets, but that didn't make it into the final definition.
Huh?
It’s serviceable, but is it ideal?
What’s the scientific advantage in categorising “planets” and “dwarf planets” as two separate categories, compared to unifying them into a single category (possibly while retaining the distinction as two different subtypes of “planet”)?
Which system would be more scientifically useful? Which would be more parsimonious?
1. Yes, there are culturally significant things that have happened since the 1930s, including the discovery of Pluto and its designation as being a planet. In fact, in 2006 -- far more recently -- a group of people got together -- known as the IAU -- and they also performed a cultural act amongst themselves when they decided to stop calling Pluto a planet, undertaking a social process ("voting") in adopting criteria for doing so.
2. If you would rather define a planet as a wandering star that's visible to unaided humans in the night sky, I'd respect that, and I kind of like the idea. It's somewhat romantic, and it avoids the myriad issues that the article here discusses that have caused the 2006 IAU definition to start to smell bad. However, it's really none of my business. The problem comes up when you police what other people call things, not when you decide to subscribe to the IAU of your own volition.
Because apparently sometimes between the moment I left elementary school and he went there, some dudes decided that Pluto didn't qualify as a planet after all.
Our understanding of the universe is after all quite rudimentary. How many centuries did people fantasise about forests on Venus?
You would think this group of well educated, critically thinking adults would go "sure", but something fundamental in their brains just refuses to let them accept this meaningless change to their lives.
Now scale this up to actual impactful topics like religion, politics, relationships, race and more and most conflicts around the world start to make sense.
(I say this as someone who doesn't care either way whether Pluto is a planet or not.)
I vote we cut science funding for universities since the humanities are clearly going through difficult times.
It’s plainly un-American to have speech governed by a committee. Thankfully, the IAU has no authority over me. Why won’t people leave me alone over my decision to not tether my own positions about how I use my own native language to the whims of the IAU? It’s as if we have thoughtcrimes now, with vigilante irritators at the ready.
Historically and culturally, Pluto is considered a planet. An IAU classification shouldn't be used to try and retroactively change that, because the IAU does not have control over history and culture. It's a fun fact (did you know that Pluto is not classified as a planet by astronomers?) not a diktat.
Similarly, a banana is 'officially' a berry, which means that it is classified as a berry by botanists. This does not mean it is considered a berry in any other contexts. If you told someone you had made a berry crumble and it was filled with bananas, you would look strange. We have countless examples of this (often focused around food): a tomato does not belong in a fruit salad no matter what botanists say.
Different terms are used with different specificity in different settings. Language and culture and [older disciplines] are not governed by the rules of [newer disciplines or bodies]. If people with 'I love space' t-shirts would stop "um actually"-ing, no one would have a problem.
Conclusively, science class would not teach Pluto as a planet (it should after all stick to the science) and English class will discuss the cultural impact of planet Pluto! Maybe write poems about the importance and impact of 9 word mnemonics? Sounds fun.
My headcanon is that people would hate it so so much! I can't wait to see that as a distant observer.
People need to understand the dynamic between science and society, because that is an important part of how the world works today.
Pluto is an exemplar.
And also, the value of culture. It might not be a scientific result, but it still shapes our experience of the world. Pluto is beloved.
It honestly doesn't have to be a bunch of drama. The problem will pretty much go away after the current generation who grew up learning about Pluto as a planet dies off and gets replaced by a generation who always knew that there were only 8 planets in our solar system. Hopefully they'll also be better prepared to accept changes that come from better understanding.
What would you say to scientists and laypersons who consider Pluto to be a planet? How would you persuade them to your own viewpoint? Please give at least three examples and use at least three paragraphs.
Some people remember being told that it was a planet when they were kids and they cling to that even though we've learned that it doesn't make sense to call it a planet anymore.
Apart from that it shows up as a planet in literature, almost all of which was written before we knew better, just like how the idea of earth being at the center of the universe shows up in literature and was once a part of our culture. The geocentric model had passionate holdouts too, but we've mostly moved on from that idea since and I think we're better off for it.
For scientists and laypersons who aren't just holding onto "planet" for sentimental reasons, I'd recommend the book "How I Killed Pluto and Why It Had It Coming"
The word “planet” is neither true nor false. Different people use it to refer to different things.
Kind of like the word “tree.” Some things are trees and some things are not — and it really depends on whom you ask and when you ask them. Most people are able to get along and allow people to refer to whatever trees they want to, because it’s a free country and it really doesn’t make sense to try to control other people over something like that.
No one is trying to control you by defining what words mean. In fact, you're still fully free to call anything you like whatever you want. You risk being misunderstood in certain contexts or assumed to be ignorant in others, but no one will stop you. My guess is that what you personally call a planet or not wont come up very often and will matter very little to anyone else.
My language has become politicized. Either I go with the flow and surrender something about my own language, or I risk getting called out or misunderstood as being incorrect if I continue.
It’s easier to let them think they corrected you than to explain your position. People believing that correcting others over superficial word choices counts as being scientific… it’s disappointing.
But that’s not what happened here. The definition was changed. We didn’t learn anything new about Pluto that made us say “ah, we thought Pluto had a solid core but apparently it doesn’t, so it’s not a planet”. All the relevant facts about Pluto remained the same. The reason why it’s no longer considered a planet is because of the term ‘planet’, not because of Pluto.
I disagree. Quibbling about a definition like that is like quibbling about whether a certain bird is a black-crowned Night-Heron or a black-crowned Night Heron (without the second hyphen), which is a real controversy that took place.
I suppose it shows a socially constructed, human aspect of science, but it really has very little to do with actually understanding the universe. The universe doesn’t care about our arbitrary stamp-collection-style classification of objects. There’s no equation or physical theory that describes the difference in any meaningful way.
The universe doesn’t care about our arbitrary stamp-collection-style classification of objects, anymore than it cares about where elements sit on the periodic table, but for us humans having things classified and ordered is a big deal. It's our constant arbitrary naming and organizing and classifying that allows letters to get delivered to my house and packets to reach my network. It gives us more precise language and enables better focus on what matters. It helps build a foundation for teaching and research. It helps to catalogue all we've learned. While you'll find plenty of ego fueled petty squabbles around the naming and classifying of things, it's still a pretty big part of what science does and we'd struggle to teach or coordinate any sort of meaningful science without it.
In many ways, the Pluto situation is an example of the Buddhist metaphor about the finger pointing at the moon. The finger is not the moon. Obsessing over the definition of "planet" to that degree doesn't actually achieve anything useful - it's a classic example of confusing labels with the thing being labeled.
The Pluto "controversy" was just bad "science" being committed by a committee.
There are people who feel that it's worth classifying all the objects in our solar system and that doing so is useful. It's pretty much always been that way. The original definition of "planet" was used to classify things visible in the sky and the criteria was simply "stars that moved". The Sun and Moon were "planets". Asteroids were "planets". We've been constantly updating our classifications ever since as new information became available (see https://en.wikipedia.org/wiki/List_of_former_planets).
Pluto was discovered in 1930 after a pair of photographs showed another light in the sky had moved. Until the 1990s we thought Pluto was alone out there at the edge of our solar system, but then we discovered 15760 Albion, followed by another new "planet" named (181708) 1993 FW followed by the discovery of hundreds of other tiny objects until it was realized that Pluto wasn't alone at all. There was a massive belt containing a vast number of small objects past Neptune and Pluto was just one of those small objects (see https://upload.wikimedia.org/wikipedia/commons/5/5b/Kuiper_b...). The discovery of a bunch of objects of similar size and composition to Pluto, Eris in particular, made it clear that Pluto just wasn't like the other planets in our system. We had 8 large planets that acted similarly and one tiny planet that was unlike the others because it was just part of a much larger system of smaller objects.
It made perfect sense to refine our definition of what a planet was taking our new understanding into account. It's also reasonable that the job of doing that wouldn't fall to one person to decide on their own. The International Astronomical Union was already responsible for maintaining a set of astronomical naming conventions from the names of stars to the names of specific planetary features like craters. Since we wanted to have a standardized distinction between planets, moons, asteroids and comets and all the other objects in space who else do you think should do that? Having a committee of experts from all over the world seems as close to an ideal as you can get.
As for the definition they settled on being "bad science", it was debated and voted on. There were alternatives proposed, but none of them won out. If somebody ever comes up with something that is clearly better, especially as we learn more about objects outside of our solar system, that option can also be considered and voted on. What other process should we have for those kinds of decisions?
Up to a point. Part of my point is that the specificity of the new definition of "planet" is a bit silly. It's completely arbitrary. It's certainly not uniquely correct in any sense.
It's also a kind of post-hoc definition which assumes our specific Solar System. For example, let's say you had a rocky body, around the size of Mercury, that had a very eccentric orbit that only reached the Kuiper Belt every few hundred years, at its apoapsis. Would this object "clear its orbit"? Hard to say - the IAU definition isn't precise enough to answer this.
The IAU definition is basically the answer to the question: how do we label the closest eight planets to the Sun as planets without saying that's what we're doing, because we don't want to have to add a whole bunch of KBOs to the list of planets?
None of what the IAU did here constitutes anything resembling real science.
Botanical berries: Bananas, tomatoes, grapes, cucumbers, eggplants, avocados and peppers, but NOT strawberries, raspberries, blackberries or mulberries.
Scientists really should have made up their own categories instead of using our words.
The word “planet” signifying a certain reverence, and the fact that a scientific body was now policing everyday language — for the apparently petty reason that we should not honor Pluto as we once did — it was quite a misstep for how people in the public might view science going forward. Unless, perhaps, the idea was to make people more skeptical of scientific results and statements.
That would also have had an impact on the public view of science. Perhaps not as bad, but it would have had an impact.
I’d encourage you to think about the impact of science fiction on interest in science. Culture is an extremely powerful force. I don’t think your concern would bear out.
As the article here explains, the 2006 IAU definition doesn’t really make sense or function as a useful model for what a planet is.
If we're segmenting off "modern astronomy" then Pluto wasn't even discovered yet.
And we discovered Ceres long before Pluto. It would be pretty rude to keep excluding Ceres just because we knew about the asteroid belt before we knew about the Kuiper belt.
I’m not a member of the IAU. I don’t adhere to their linguistic prescriptivism, and nobody should expect that I will. Some of their own members do not — the article here explains.
Are you a member of the IAU?
I’m not the IAU, and I have no interest whatsoever in emboldening thousands of people to smugly harass you or anybody else about it.
If you believe in the "standard 9" you're just insisting on returning to a scientific definition of planets but one that is frozen on our scientific understanding from a few decades ago...
If you don't like changes to what people call planets, you should be unrolling all the other changes that have also been made, and go back to the original definition that stood from ~200 BCE-1700 CE.
If they could do it all over again probably most of them would. The sciences all grew organically too. Some of these things like "berries" aren't even just the product of one reclassification, they're the product of several over the course of decades or centuries, which is how they get so common-sense silly over time.
Doesn't really matter. The public would end up taking science words for their own purposes to sound legitimate. Look at how "quantum" and "energy" is used in alternative medicine.
This is the actual problem everywhere.
It gets worse. Whales and dolphins are more closely related to certain fish than those fish are related to some other fish. (As are we by the way.) There are also some fish, such as lungfish or certain eels which can spend more time out of water than whales and dolphins can. Some fish can even breathe air, which undermines another assumption about whales etc.
For some reason, I rarely hear fewer people objecting to jellyfish or shellfish being referred to as fish, even though these are more distantly related to fish than mammals are.
So biologically, the term "fish" doesn't make much sense.
As others have stated, there appears to be some kind of spectrum. Some of the inner planets have more in common with the moons of Jupiter and Saturn in some regards, than they do with Jupiter and Saturn themselves. For a start they have a surface that can be landed on. (Maybe not so much in the case of Venus or Io!!!)
Pluto's most obvious problem is that it is too similar in size to a large number of other objects. But it does have some resemblances to planets and larger moons. I'm not keen on the phrase "dwarf planet" because it makes me think of objects that are much smaller than Pluto is.
A very brief period of history. Give it 50 years and the number of people who will call it a planet will be close to 0.
Let's not overstate Pluto's significance in culture. People call it a planet only because that's what they were taught in school. Not because of other (very few) cultural references. As it has been dropped from the curriculum, so shall it be dropped from people's minds.
Compared to the other planets it's rarely referred to in stories, etc. It has very little significance in today's culture beyond the fact that it was taught in school.
That's not the case for something like Jupiter. If they decided tomorrow that gas giants are no longer planets, it will remain in arts and culture. Pluto? Highly unlikely.
I don't think my kid knows about Pluto. That doesn't bother me in the slightest.
It's an odd way to analyze it. Plenty of things have been known for longer and it doesn't bother us if they're not taught in school, etc.
When people stop referring to Pluto as a planet, it will cease to be one.
Until then, we are living in a reality in which Pluto both is a planet and is not a planet, depending on the context.
I'm not disagreeing. What I'm saying is that compared to most other planets, people are going to stop referring to Pluto as a planet, by the mere fact that they'll stop teaching it in school. It has no cultural momentum unlike Mars, Venus, etc.
Have whatever emotional relationship you like with "Pluto" and don't wait around for others to validate it. It's fine. Nobody can stop you. I'm a bit fond of Ceres myself. Nobody can stop me. Nobody needs to approve it. Take control. Write your own headcanon.
There’s no need for a god complex. Stop picking and choosing which planets are real. Scientists can create their own, more precise words for things. Planets are sacred. Things that clear their orbits are not.
You can’t subdue the public into giving up their gods out of difference to science — you’re just losing people.
And more importantly, why does the incredibly recent addition of Pluto to the list of planets not fall under scientists "try[ing] to exert control over other scientists and members of the general public"? You'd have a point if the planets were set in stone for hundreds of years, but as-is I can't follow your logic why one is okay and the other is not.
We don’t have a problem with armchair scientists correcting people about the 1930s discovery of Pluto and how it was discussed at the time, we have a problem with armchair scientists being aggravating when people want to engage with the idea of Pluto today and refer to it as a planet.
But I have a feeling that the problem you see is just a fairly normal social mechanism: if you use words differently from the majority of people, you will keep getting corrected because:
- some people might be genuinely trying to troll/aggravate you the way you're describing
- BUT: others might genuinely think you've made a mistake and try to correct you, unaware of any discourse
- and finally, other people might just disagree and attempt to discuss
No conspiracy is necessary to meet plenty of people who disagree, and the level of accusations you're throwing around tells me you might not be able to clearly categorize everyone.
Even if the person correcting you isn’t acting like an overexcited 13-year-old jumping up to correct someone about it, you must agree that as a point of discussion — as a matter of good taste and manners — telling someone that Pluto isn’t a planet is just terribly boring by now, and if that is stated as a response to something the person was trying to say, there’s a risk that attention and energy is being diluted from the actual point? Of course it happens earnestly, but there are still all of the other times and ways that it happens.
That's an objection? No, that's a benefit! I think it'd be awesome to be regularly discovering new planets.
We can still be reasonably excited about discovering new things in the solar system without pretending they're in the same category as Earth and Neptune.
Scientists regularly claim to have found planets orbiting other stars. They do this even though they have no way to verify that their neighborhoods have been cleared.
And yes, you can decide that some particular things are special. That’s why culture is a big part of this. Many people consider Pluto to be special even though they are well aware that it’s not the only one out there, and that’s why they refer to it as a planet.
The idea that there would be too many planets isn’t really a problem that needed solving. Would we start classifying every dinosaur as either a T-Rex or a triceratops because otherwise there would be too many dinosaurs? It’s plainly ridiculous.
Picking any arbitrary generic definition and applying it universally is less emotional, because there is no emotional reasoning necessary to explain why any object is or isn't a planet.
Scientists just ignore the rule about neighborhoods at times for convenience — how else would you claim to have found an “exoplanet” if you cannot also rule out “exo-dwarf-planets” in its neighborhood?
People can tell when a rule was added for a specific reason that the authors don’t want to say outright. It’s a sort of appeal to authority rather than a scientific claim. That’s dishonest, and people push back when authorities are dishonest with them.
We don’t make the rules, this is just what a planet is now. Wait, did you say we do make the rules? No, of course we didn’t vote on what our scientific result should be… that would be unscientific. We ARE science.
This makes no sense to me, can you explain WHY a universal definition is not needed?
> Scientists just ignore the rule about neighborhoods at times for convenience — how else would you claim to have found an “exoplanet” if you cannot also rule out “exo-dwarf-planets” in its neighborhood?
I might be missing a more specific critique, but IIUC, this question only makes sense to me if you presuppose that classifications must never be updated. Because otherwise, the solution is that you do the best you can with the data you have, and accept that better data might come along later and prove you missed something? The same way e.g. classifications in biology are frequently updated?
> People can tell when a rule was added for a specific reason that the authors don’t want to say outright. It’s a sort of appeal to authority rather than a scientific claim. That’s dishonest, and people push back when authorities are dishonest with them.
See, this is where you've totally lost me. I can't tell what people apparently can tell. So what is that specific reason? Do you have to wrap your allegations in so many indirect and allusions? This kind of conspiratorial-cryptic writing genuinely reminds me of flat earthers and qanon followers.
> We don’t make the rules, this is just what a planet is now. Wait, did you say we do make the rules? No, of course we didn’t vote on what our scientific result should be… that would be unscientific. We ARE science.
Did such a vote happen when Pluto got added? I genuinely don't know, but otherwise this objection makes no sense to me.
It was a fool’s errand or an act of deception to try to coerce “planet” to be a specialized word. The cracks are evident. The 2006 IAU definition doesn’t work.
Specialized words are great. They are important in science. “Planet” is not a specialized word and it has not been a specialized word for hundreds of years. Scientists did not need to somehow coerce “planet” into a specialized term to continue doing science—and if they did, there was still no reason to bother non-specialists about it, since science is its own domain where terms can be used in specialized ways.
Yes, update classifications whenever it’s useful to you. No, don’t expect other people to regard your classification system as the final word. You yourself are planning to change it anyway when it stops being useful to you, and other people have a right to categorize things differently for their own purposes — your system will be neither definitive nor universal, so it shows a lack of self-awareness to say that it is.
You mention that I make cryptic allusions. “See, this is where you've totally lost me. … So what is that specific reason? Do you have to wrap your allegations in so many indirect and allusions?” To help you to read more carefully and to apply context clues, the following is a quote from the article that this thread is about.
> To its detractors, the IAU definition seemed crafted with a specific intent. “A reason was invented to exclude Pluto,” says Kornfeld.
Nope. Just like it is okay for scientists in the field of biology to change the definition of "species" as used in their field, it is okay for the same to happen for the word "planet", even if the general public then argues everyone should use the updated definition in everyday language. That's how language happens and evolves, and that's how we got these words! If this were not the case, Pluto would never have been added as a planet. You were okay with every change until that point - yeah, of course you agree with the changes up to what you were taught, even if there's no argument for what makes them different!
You have to understand: there's no conspiracy behind the IAU that's making people argue against you! It's literally just individual people disagreeing with your disagreement.
---
Regarding your edit:
> To help you to read more carefully and to apply context clues, the following is a quote from the article that this thread is about.
> > To its detractors, the IAU definition seemed crafted with a specific intent. “A reason was invented to exclude Pluto,” says Kornfeld.
In the article, I see literally no reason given by Kornfeld to assume anything but an honest disagreement. Okay, great, they think the definition should fulfill a requirement that the majority apparently doesn't see as necessary. How do they get from this to people inventing a reason to specifically exclude Pluto? There's no reason given to assume bad faith?
Nobody is saying biologists can’t use that word the way they see fit. It would however be ridiculous for them to ask me to stop referring to species counterpoint.
> as used in their field
Now you’re talking sense. I don’t care what they call Pluto at IAU meetings. You shouldn’t care what I call Pluto in my own home.
Now consider: the public still slowly but surely follows along with changes to the classification of species, so when e.g. a species is divided into two or more species, the general population that often encounters them will most likely refer to them separately too given enough time, and the same in the other direction.
It's a simple concept: language changes, and the public likes to follow along with "mainstream" scientific use, even if often lagging behind.
I have been defending the right for myself and for others to continue using their own language, without harassment from others in the names of scientific bodies. There was a time when linguists would prescribe that words like “y’all” are incorrect to use, and people would be shamed and discriminated against for doing so. Armchair scientists are behind the linguists on this one. We have lost cultural heritage and seen beautiful dialects gradually shrink or disappear due to prescriptive linguistics, and we now understand the harms, and it’s time that it ended.
Yes, people are free to use words in the ways that make sense and come naturally to them. No, it is not appropriate for people to treat others with disrespect for doing so. Harassment is harassment, bullying people into changing how they speak is bullying. This is not a philosophical point, it’s about being a decent person.
A desire that certain people refrain from harassment is not a claim that a conspiracy exists.
A lack of originality and self-awareness is not in itself a sign that someone is conspiring with other people who lack originality and self-awareness.
So… planet Ganymede when? Or Titan?
People like to make rules. Leave them be in their tree houses, unless you really like to play too. I thought it was a right of passage in high school to laugh at the French forming committees to tell peasants how to speak their native language. We haven't generalized from this example?
Who gives a rat's ass whether this governing body thinks Pluto is a planet or not?
Flat-earthers are definitely wrong about the shape of the earth, but even they admit the sky is blue, assuming they aren't afflicted with some unfortunate variety of colorblindness.
In my observations of flat-earthers, they're people who reject the consensus surrounding a particular fact because they haven't observed that fact for themselves, which doesn't make them bad people or even crazy. I do rather enjoy their attempts to measure basic scientific facts about the earth, such as when a group of flat-earthers used lasers and the ocean to measure if the earth indeed has curvature. When the evidence incontrovertibly showed the earth indeed has sufficient curvature to match the scientific consensus, many participants were quite shocked. As long as they adjusted to the consensus, or even hypothesized another theory they felt worth testing, they're not crazy, just skeptical of authority.
I have not observed directly that a human will die after 3 days without water but having experienced thirst & dehydration in limited amounts, I have no reason to doubt that is likely the case.
That's what I don't understand supposed "rational" flat earthers. It's fine and somewhat rational to be skeptical of authority but when the contrary idea takes enormous leaps of faith to consider, it seems weird to me to believe something for the sake of it.
I know someone who is almost 40 years old that has never left his hometown. He's a reasonable person who holds gainful employment, but from our conversations, he's never been in a skyscraper, flown on an airplane, taken a road trip into the mountains, or even hiked up a large hill, for that matter. He also lives in a land-locked city, so he's never seen the ocean. As such, he has never directly observed the earth to be curved. With all due respect, many people like him do exist in the world, and perhaps you're not acquainted with people like him.
However, he is not a flat-earther because he spends much time on the Internet reading about the way the world works outside his hometown. Basically, he believes in the truthfulness of large institutions, which really is why you and I believe the earth is round; that is, we haven't actually performed a bona fide experiment (not just going in an airplane or up a mountain) to measure the curvature of the earth for ourselves, but we trust the results of those who have, and we also accept that certain technologies like GPS as it is currently implemented can only work if the earth is round (not just in satellite orbits but also the slight-but-critical relativistic shift from a geosynchronous satellite).
>when the contrary idea takes enormous leaps of faith to consider, it seems weird to me to believe something for the sake of it.
That's cool, but many people are capable of believing in something for the sake of it. One fact that stands out to me is that we all use some amount of faith to accept that the earth is round, though perhaps not quite a leap's worth.
Fair enough.
> Basically, he believes in the truthfulness of large institutions, which really is why you and I believe the earth is round; that is, we haven't actually performed a bona fide experiment
I guess to a certain extent, but also knowing that I could perform such an experiment and come up with reproducible results. As well as the lack of any credible alternative theory that holds up to any sort of scientific rigor.
> One fact that stands out to me is that we all use some amount of faith to accept that the earth is round, though perhaps not quite a leap's worth.
I would say that it's not really faith when its reproducible. For example, there is a small amount of faith that my brakes will slow down my car when approaching a corner, but I can test the brakes to know they should work, I can perform experiments with similar mechanisms to prove the basic physics, that all would have reproducible outcomes. So while there is a small amount of faith that some catastrophic failure won't happen, I would say its categorically different to believing things with almost no evidence. There is no reproducible experiment (at least that I know of) that you can even read about that proves the earth is flat.
Evidence is the key. I don't know where you stand on the Gettier problem debate (is all knowledge just JTBs?), but the Gettier problem and black swan events show that all the evidence can point to one thing, yet something else might actually happen. So, did you really know, or did you just believe? I guess flat-earthers just reject what 99.9% of people accept as knowledge and hold it instead as competing belief with whatever alternative system quacks well enough to pass as a duck in their squinting eyes.
I haven't, and you probably haven't, though if you have, I'd love to hear that story. As I said, they're skeptical of authority and need to run the experiment themselves; some will even flip on flat-earthers who run the experiment and change their minds. Only those who perform the experiment and still refuse to accept the outcome are deserving of being left to their own crazed devices. Until then, they're just ignorant and/or weird.
There are of course people like grifters in the community who don't believe their own words, but the believers won't reason themselves out of this position they didn't reason themselves into.
- Orbits a star (Pluto does and I assume that's what you were asking about)
- The object has enough mass to pull itself into a sphere (meets this criteria)
- The object has enough gravity to have cleared its nearby orbit of debris and other objects
Neither Pluto nor Eris qualify for a planet because of that last one and, like I mentioned, the Moon has more mass than Pluto and Eris. The Kuiper belt objects all have this issue, but my point was that dwarf planets are pretty small - especially compared to other objects around Sol. If you walked non-stop around the Moon it would take 91 days compared to Pluto's 62 days and Eris's 61 days.
The designation of dwarf planet is not that big of a deal imo.
Many problems can be solved by application of sufficiently powerful explosives.
(*) Or, possibly, eject it from the Solar System.
Project sundial was ~10Gt of TNT, but dispersing Pluto would require a billion times that (~5E27J).
I believe someone was trying to make a name for themselves here and ignoring the history of Pluto and its discovery.
How is it pseudo-scientific?
This is like when English professors gripe about word usage in books. That's wrong, you can't do that. Then society at large does it and it becomes correct usage. We define our world.
As human beings we're allowed to make these kind of decisions. We define ourselves to be outside of the animal kingdom when we're clearly part of it and a type of animal ourselves.
The question at hand is "how do we define a planet" from a universal standpoint, because it hadn't really been defined beyond an "I know it when I see it" level and that was becoming a problem.
Objective rules that do not assume you're talking about our solar system are key here, and the serious proposals basically come down to 8 planets or dozens and growing, and from a practical standpoint the former was the obvious choice IMO since all it really affects is what gets focused on in general education environments.
If you just want to make an arbitrary decision that these things are planets because you want them to be as opposed to because they meet certain criteria, that's not useful to anyone.
Pluto is the Princeps of Kuiper Belt Objects, the First Among Equals. It is the most honored KBO, even if it is not a planet.
still works, how bout that?
Why bother coming up with a pseudo-scientific requirements list for planets when these don't work for a large number of cases.
It's really hard to come up with a definition of a planet that includes Pluto but doesn't include Orcus. Orcus is very close to a mirror of Pluto that is 120 degrees out of phase. Even in name: Orcus is the Roman name for the Greek god Pluto.
If you want to say that Pluto is a planet for historical reasons, that's fine. Just don't try to invent pseudo-scientific nonsense to justify it at the same time you are decrying psuedo-scientific nonsense.
A Kuiper Belt Object not being a part of Solar System doesn't make any sense. A star system is the star + all objects that orbit it. Why would you arbitrarily exclude some objects that orbit the Sun?
There is because Pluto is inside the Kuiper Belt and just as much a part of it as all the other "planets" in there. There's nothing wrong with defining our solar system as having 8 planets plus a bunch of other stuff.
Eris is bigger than Pluto, so if Pluto’s a planet then so is Eris. So you have 10 planets.
And then how many other Erises are still hiding? How many planets do we have then? It must be some very large unknown number!
Holding the true number of planets to be a large unknown number was anathema to many.
The demotion of Pluto was primarily motivated by a desire for the word “planet” to refer to a fixed, never-changing number of large bodies orbiting the sun.
Which is exactly how I remember learning it at the end of highschool (discovered during my junior year): Hey, did you know we just discovered a tenth planet?
100%
Scientists try to coin new terms all the time. It’s great for the researcher if people actually use it. But why do that when you can just sign your name on a term everyone already uses?
Redefining “planet,” from the 9 culturally accepted symbols into something else, was a swindle. “Things that clear their orbits” could have been TTCTOs. It happens all the time, coining precise terms for things. Why should this one have been any different? The public was right to push back and to protect their mythology.
In terms of financial motives, I would reason that a motive for extending the term “planet” to cover the innumerable large objects orbiting other stars would have been as a better sales pitch to Congress. Studying “planets” lightyears away was a sort of brand hack which would have driven more funding. And when the “planets” was established as comprising a virtually infinite set, rather than simply a list of 9 known objects, the nomenclature collapsed in its usefulness, which is why the IAU started looking for a way out of its own hole.
However, as the article here discusses, the IAU’s approach has pretty much failed. It doesn’t hold up to scrutiny as a thing that’s meant to be usefully applied. How exactly do you confirm that all of those exoplanets have actually cleared their neighborhoods, or is the truth that it never actually mattered to anyone in the field?
Have any scientists or agencies written papers or reported to Congress that they discovered or studied some exoplanet — using public funds — when in fact they had no way of confirming whether its neighborhood was cleared? It sounds completely improper to me, but the reality is that it never really mattered.
Scientific institutions: be nice or don’t be surprised when the general public votes to cut your scientific research funding or won’t accept important advice from experts.
If you aren't you are totally inconsistent and just want what you were taught in elementary school be true.
When I think of what a planet is, I think of a destination. Somewhere that maybe in the far future we could visit one day. I think the definition for a planet should be a body with sufficient gravity that we could reasonably orbit and land on. And we can have as many sub-classifications as we want from nano-planet to Mega-planet.
So in classical times, the Sun and Moon were classical planets, on the same plane as Mercury, Venus and Jupiter and all the rest. Since the Sun and Moon were planets, they could figure in astrological reckoning in certain ways. And face it, from our observer's perspective, they have a lot in common with actual planets.
In fact, the seven days of the week derive from seven planets: SUNday, MOONday, Mars, Mercury, Jupiter, Venus, and Saturn. (It helps if you list them in Spanish rather than Germanic tongues.) No, there was no EARTHday or URANUSday (thankful for small favors.)
And in school growing up, many of us learned the nine scientific planets as traditionally defined. Uranus, Neptune, Pluto: all great modern discoveries to add to our pantheon. So nine is a good number. Lots of people can memorize nine and keep a set of nine in our heads.
But then they discovered a tenth and an eleventh and a twelfth, and scientists began to get nervous, because something was up: there were, potentially, dozens or hundreds of "planets" to be discovered at this point, among the asteroids and among the Kuiper Belt. That's all well and good: we can name a lot of bodies out there, but school children cannot learn 3 dozen planets in a row! School teachers would never stand for it! So tedious!
So there you go: the canonical list of planets needed a hard-cap and so, they lined up the 8 we had, and found all the commonalities, crystallized those into the definition, and then circumscribed the list so that it would never again grow without bound. It's not unfair to have a lot of planetoids, or dwarf planets, or asteroids and other things, just floating around. But, the good news was that third graders wouldn't need to memorize them all, and third grade teachers wouldn't need to model a solar system of 30 wonky planetary bodies.
And it's that simple, really. 8 standard planets makes for good basic astronomy, good solid astrology going forward, and peaceful middle-school curriculum. Everything else is just semantics.
Then after you tell this whole larger story the whole idea of Pluto being something other than a planet makes a lot more sense to people since it was originally based on the idea the solar system has a lot fewer types of features than we know it has.
But the Pluto planet demoters didn't do this. The started with the present decision and just referred back to the history in bits and pieces, and out of order.
And worse than not arguing for their position as effectively as they could, they missed an opportunity to get the public interested in the whole story and how it is continuing to evolve today in various ways.
The 2006 IAU definition was explicitly scoped in a limited way so that it does not apply to anything beyond the Solar System.
Planets outside the Solar System are not held to the same level of scrutiny. Over 6000 planets have been discovered outside the solar system, and none of them are required to clear their neighborhoods to be designated as planets. The IAU’s Official Working Definition of an Exoplanet can be read at: https://www.iau.org/CommissionF2/CommissionF2/Documents.aspx
So, if someone really thinks we ought to have a universal definition for what a planet is, then they might start by having a word with the IAU.
Since the accurate detection of small non-glowing objects becomes exponentially more difficult as you look further out, that seems like a perfectly reasonable explanation - far more reasonable than the evil cabal of astronomers conspiring to defeat Pluto's defendants with organized harassment campaigns...
https://news.ycombinator.com/item?id=49528442
You see where you are calling into question whether the IAU have something to do with the "legions" who you've been in other comments saying are harassing you?
Are you a member of the IAU?
The rest of that post clarifies that this is a problem caused by certain “armchair scientists.” Members of the IAU are in fact actual scientists, not armchair ones.
In celestial mechanics, "clearing the neighbourhood" (or dynamical dominance)
around a celestial body's orbit describes the body becoming gravitationally
dominant such that there are no other bodies of comparable size other than
its natural satellites or those otherwise under its gravitational influence.[0]
It’s like saying Jupiter is not a planet because the Trojans exist.
If you have to argue that it doesn't apply to Jupiter or Earth because they are obviously planets, it implies that "clearing the neighbourhood" is a vague and not particularly useful criteria.
Jupiter, Neptune and earth in your example dominate the gravity of their orbit by locking the smaller bodies into orbital reasonances.
It’s not a vague criterium. It might be an irrelevant one if you are interested in geophysics, but it’s concrete and testable.
In addition to what other commenters said about orbital resonance: Neptune has approximately 20 times bigger radius and is about 10_000 (ten thousand) times heavier. This is comparable to difference in mass between a human and a hummingbird. Could we really call them "comparable size"? I'm not sure, this is not a particularly precise term, but I would say - no.
Also, if you have the opportunity too see @plutokiller teach planetary science or give a lecture, I can recommend you do so!
Most recent example I found was the Swatch MoonSwatch Collection [1], which includes the Sun, Moon, eight planets and Pluto[2].
1. https://www.swatch.com/en-us/bioceramic-moonswatch-collectio...
2. https://www.swatch.com/en-us/mission-to-pluto-so33m101/SO33M...
To use a different phrase from wikipedia, "orbital dominance".
Other objects that stick around are either captured as satellites or forced into resonant orbits.
> The Sun attracts the Moon more strongly that Earth does, so does that mean that the Earth doesn't fit the criteria?
The Earth's sphere of influence goes out to about a million km, 2.5x the moon's orbit.
1. When the IAU voted to demote Pluto, it was the last day of a conference and most of the attendees had already headed home.
2. Pluto has 5 known moons. The week before the New Horizons flyby its computer crashed. This necessitated a multi day reboot. During this downtime the probe had been scheduled to be hunting for additional moons. This hunt never happened. Would Pluto still be a dwarf planet if it had 10 instead of 5 moons?
I see what Schindler did there!
My Very Easy Method Just Speeds Up Naming Planets
And it was so convenient! Does anyone know a good alternate now that the P is gone?
My Very Easy Method Just Speeds Up Naming
Asteroid belt in between and the second asteroid belt (the Kuiper belt) on the outside.
Then the Oort cloud surrounding the whole thing as a shield to protect the system from alien incursion.
Classifying Pluto as a planet is problematic because it lacks the behaviour and characteristics of something that formed according to theories of how planets form. If you tried to describe what a planet should look like based on the nebula hypothesis, you would not be describing Pluto.
Instead it has behaviour and characteristics a lot like the many trans-Neptunian objects, so it makes more sense to classify it that way.
In cuisine, they are vegetables.
- not a star
- not orbiting a planet
- roundish
- greater than 1000km radius
That would restore Pluto to its rightful place and add Eris.
Because honestly anybody who played stuff like KSP RSS or any space game taking place in our solar system represented at scale with adequat orbit weirdness probably told themselves "that's Pluto? Ok i get it, not a planet".
Anyway, 9 is not an option, you must choose 8 or 10+.
What logical rule would you propose that allows Pluto to be a planet without also bringing in a bunch of others?
If you just want to arbitrarily declare things are they way you like them to be, religion is over there.
The rule would be: pluto is a planet, stay mad nerds
Next time you go to the grocery, grab a cucumber and a watermelon and try to find the differences.
Is it Art? It's not Art! Are bananas a vegetable or a fruit? Pluto definitely is a planet! No it's not!
Jesus, what a waste of energy.
Are we just realizing that asteroids come in all sizes? Do we really need a sharp boundary between those we call planets and those we don't call planets?
Can we consider planethood a spectrum? Like should we REALLY care if someone says there are 9 planets in the solar system, and the next person says 8?
We used to say there were 3 oceans, now there are 5. In reality, there's just one big saltwater lake. Do people fight about where one ocean ends and where the next one starts?
Let them call pluto a planet if they want, let them call pluto a kuiper object.
We shouldn't give a fuck.