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Nice meme. I think this is true of taxonomy in the broadest sense as well. Just look at how mad people get about pronouns for one example.
I can’t even describe how much I hate adjectives.
I really intensely love adverbs though
Taxonomists will be the first to tell you the field itself isn’t an exact science. I think some people find that to be more exiting.
and linguists will be first to tell you that languages are living, fluid, and made up for the purpose of communication
and yet people started getting mad at the mere concept of pronouns
Yet it’s always the unclassified stuff that makes life fun.
1400s: Whales are furious sea-gods
1600s: Whales are big fish
1800s: Whales at not fish, they are mammals
2000s: Whales are big fish
2200s?: Whales are furious sea-gods
2000s: Actually, fish aren’t fish
https://www.sciencealert.com/actually-there-is-no-such-thing-as-a-fish-say-cladists
Or, conversely, mammals are fish https://theconversation.com/the-absurdity-of-natural-history-or-why-humans-are-fish-69384
that’s a dumb way to categorise things, like it’s an attempt to create a categorisation system that works against how we use language. it’s less “either everything is a fish or nothing is a fish” and more “we decided to take the meaningful word “fish” and devoid it of meaning for the purpose of making our graphs make sense”, what about the definitions of the word “fish” that aren’t based entirely on one specific point of view of a subgroup of scientist?
we use language in different contexts. In the food store “fruit” has one meaning, while in a botany paper, it has another.
This doesn’t say theres no such thing as fish generally, it says there is no useful definition for it in a biological setting.
yeah i get that this perspective can be helpful in specific contexts, what annoys me is that it’s presented as universal, “no such thing as fish”. i would appreciate added clarity as to the point of view of the speaker, so such statements don’t come off as general words everyone should just accept as truth
I recently read about a living whale that had a late 19th century harpoon stuck through its head. I didn’t fact check it, but if true, furious sea gods feels like a valid reinterpretation
This applies to so very many human endeavors.
And the IAU got it wrong when they reclassified Pluto. Jupiter and mercury belong in the same category but the moon and mercury don’t? Get the fuck outta here
You sound like a lunatic traumatised war veteran. The war has been over for a long time, the decisions have been made and there is no going back, my friend.
And to add,Jupiter and Mercury belong in the same category as in they both orbit a star (the Sun in this case), both have enough mass to be spherical, and both have clear most of their orbits.
But the category of planets has sub-categories. Mercury is a rocky terrestrial planet while Jupiter is a gas giant as the former is smaller and rocky while the latter is large and made of mostly hydrogen and helium gas. Gas giants can also be called “Jovian planet”, but Jove is just an alternate name for Jupiter (the god) so you’re basically calling Jupiter a “Jupiter planet” which I think is a bit ridiculous but whatever it’s fine. Both are still, of course, planets. It’s like a large tree and a sunflower. Both are still considered plants, but certainly in different subclasses of the category of plant.
Dwarf planets, although not proper planets, are still very interesting objects that could even harbour life in oceans below their icy surfaces. Also, Pluto is not alone in the dwarf planets classification. There’s also Eris, Ceres, Makemake, and probably thousands more we haven’t discovered yet!
There’s also plenty of classifications of plants based on form! Non-vascular plants, woody plants, herbaceous plants, algae and lichen…
Most of our “rocky” planets are pretty wet though. Mars is drying out, but Venus is caked with volatile chemicals and Earth is downright infected. Only Mercury is really barren, partly due to it’s small size. I could easily see three categories for gravitationally rounded bodies that can’t fuse hydrogen: Dry planets (usully smaller), Wet planets (usually larger), and Gaseous planets (gas giants).
I’m pretty sure Pluto doesn’t orbit a planet, so it’s not a moon. And the Moon, not only is it named a moon, but also orbits a planet, so therefore is a moon. One is a moon and the other is not a moon. Moon, not moon.
Pluto and Charon orbit each other. The barycentre (the center of mass they both orbit) is far outside of Pluto. The Earth-Moon barycentre is still inside Earth, though this could be changed by moving the Moon further out.
Either way, Earth, the largest rocky planet, could be made into a moon by sending it to Jupiter, so I don’t think being a moon should disqualify a celestial body from being a planet.
One of the main criteria for a planet is that it orbits a star. Moons don’t orbit stars and hence not planets. If Earth was orbiting Jupiter, it would be a moon but not a planet. Moons could harbour life too! Titan (which orbits Saturn) has an atmosphere, and Europa could have subsurface oceans under all that ice.
That definition means a planet has nothing to do with physical state, and everything to do with the proximity of your neighbors. We could promote the Moon to a planet by pushing it further away, or demote Earth from being a planet by slinging it a bit closer to it’s hungry uncle Jupiter. We could demote all planets by extinguishing the Sun! Then the entire system stops working and it’s all just asteroid or something.
That arbitrarily chosen definition doesn’t describe the object, only it’s place in the malleable hierarchy. With this, the title of planet tells us nothing about the object itself, except that it’s orbit is only dominated by a star.
Even worse, the IAU definition is extra arbitrary, as it only counts objects that orbit specifically the Sun, so the vast majority of bodies in hydrostatic equilibrium that don’t fuse hydrogen aren’t planets. They also play very lose with hydrostatic equilibrium, as Mercury isn’t in hydrostatic equilibrium, yet is explicitly classified as a planet. And “clearing it’s orbit” is also rather indistinct, with no method to determine this is given. It’s up to argument if Neptune is a planet, as many plutoids intersect it’s orbit.
Even more worse, the barycentre of our solar system is sometimes outside of the sun! That means sometimes the Sun is co-orbiting with the rest of the solar system bodies, and therefore by this definition nothing is a planet! It’s a definition so arbitrary that it periodically stops existing!
I’m not just saying I disagree with the IAU here, but that their definitely is objectively poor, and poorly used. I agree that Pluto, Eris, Ceres, and many others should be in a different category from Jupiter, but make some categories that make sense, please!
Why does the definition involve location? Intrinsic properties make more sense. Who cares what it orbits or what else is is in a similar orbit?
Moons are defined as naturally-formed objects that orbit a planet. Natural satellites, basically. What’s wrong with that definition? The Moon is a moon, but Pluto is not. Moons don’t have to be a fixed size, Earth’s moon is relatively big compared to the planet it orbits, Ganymede is larger than Mercury, and some moons are teeny tiny. If you tried to classify them based on size, you’d have a million different categories.
I’m saying that (many) moons are planets too. Anything big enough to be round, but not big enough to burn hydrogen, should be a planet regardless of where it orbits.
But how round is round enough? What about the millions of asteroids floating in the asteroid belt, many of those are spherical. Should they be considered planets? No, of course not. We can’t just call everything that looks like a sphere a planet. That’s ridiculous.
It was decided that planets 1. should have a stable orbit around a star 2. have enough mass to become spherical (that’s your point) 3. massive enough to clear its orbit, which in our Solar System means there are 8 planets. Pluto is surrounded by millions of Pluto-like objects in the Kuiper belt. Pluto, as well as its buddies Eris, Makemake, etc. are classified as dwarf planets because they are not massive enough to have cleared their orbits.
Dwarf planets are cool too, they might even have life in subsurface oceans under all that ice :0
Moons are not planets because they don’t orbit a star. Stars are pretty well-defined, objects where there is enough mass for nuclear fusion to occur. Planets are definitely not stars, so moons are not planets.
You’re just repeating the definition that I’ve already made clear I disagree with. This definition isn’t science, it’s taxonomy. Taxonomy is just a tool; we group similar entities together so we can characterize them. A body’s orbit and neighbors aren’t as important for that purpose as other attributes like size and composition.
Should they be considered planets? No, of course not.
Why not?
how round is round enough?
I’m sure the IAU can come up with a suitable boundary. The lines are always fuzzy.
The IAU did come up with a boundary: having enough mass to clear (most of) its orbit. That’s because simply mass and roundness are pretty arbitrary numbers that could be set to anything, while clearing the orbit is decently well-defined, at least mostly. It’s a good post to set as the lower limit for the mass of planets. That’s why Ceres is no longer considered a planet as well, there’s millions of asteroids in the Asteroid belt and it’s not massive enough to get rid of them. Similar reasoning goes for Pluto, Eris, Makemake, and their friends in the Kuiper belt. They’re not massive enough to clear their orbits of all those asteroids and other small objects.
Well orbits and neighbours and such I would argue is very important in astronomy. If you were all alone in the void of space and there is nothing else that exist, there wouldn’t be anything to compare against. The idea of relative size, mass, rotation, position, and even time wouldn’t really exist. The whole idea of moons is that it orbits planets, no matter its size, composition, or mass as long as it was naturally formed (hence why the ISS is not considered a moon, it’s an artificial satellite). Planets, by definition, are objects that orbit stars. Moons don’t orbit stars and hence cannot be planets.
I’m not very good with analogies, but here me out. Imagine the hands of a clock, all alone with no clock for the hands to tick. They may as well be pointy bits of metal, they are not hands without the clock. Just as moons are but rocks when without a planet, or how planets are not so without a star.
I’ve heard (from people who have credentials in this stuff) that the people in the room at the time were mostly orbital mechanics people. The planetary scientists weren’t there. That’s why you have this “cleared its orbit” rule. If there were more planetary science people in the room, Pluto might still be considered a planet. And it may yet change back.
It’s either remove Pluto or add a dozen other “planets” to the list, most of them in the middle
They should have done that
Yes they should have. Fuck Mike Brown.
