It’s all just made up categorization. It’s like that because astronomers have agreed to categorize them like that.
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IAmNorRealTakeYourMeds@lemmy.world 3 weeks agobut so not?
we used to have a handful of elements, but when we kept discovering more, we didn’t change the rules to have elements, and “steange elements” so schools only have to teach about 16 elements.
prole@lemmy.blahaj.zone 2 weeks ago
umbraroze@slrpnk.net 3 weeks ago
Well elements are elements. All of them are just protons and neutrons and electrons at the end of the day. They have different properties but all of them behave by the same rules.
But there’s some big differences between the various kinds of bodies orbiting the Sun and how they’re orbiting the Sun. Big asteroids were considered planets, until we discovered there’s a shitload of them and they’re all in roughly the same area. When it turned out Pluto is basically in the same situation and there’s a lot more of the transneptunian objects, it was pretty clear that Pluto isn’t special. If you compare it to planets it’s pretty weird. But I think it’s good that they created the dwarf planet classification because that also elevated Ceres back, hell yeah.
IAmNorRealTakeYourMeds@lemmy.world 3 weeks ago
I’d rather we have dozens of planets, with news articles talking about “new planets discovered”
we can still teach the handful of “classical planets”, so we can have posters, or have like periodic tables, and everyone be aware that they might go out of date as more is discovery.
the solar system will be more exciting and more varied.
also, the “clearing orbit from similar objects” is time and orbit dependent,
larger orbits take longer to clear, which mean in a few billion years ceres might eject pluto and become a planet?
or we could have gas giants beyond pluto (like this hypothetical 9th planet ) which it would be unlikely it has cleared its orbit, so we could have a planet larger than Jupiter which we would call a planet, but if we discover another planet in its orbit (too large to clear), then we will have to say that it is a dwarf planet.
squaresinger@lemmy.world 2 weeks ago
The main issue here is that everything from a speck of dust to the massive black hole at the centre of the galaxis is pretty much the same thing on a large spectrum.
You can clearly say that some grains of dust are something entirely different than a supermassive black hole, but it’s really hard to find solid cut-off points to categorize anything in between.
So we started with a handful of arbitrary examples for each category, which was easy when we only had these examples, but with more and more discoveries the gaps between these examples are filled and it becomes a spectrum, and then it becomes iffy what exactly fits into which category.
IAmNorRealTakeYourMeds@lemmy.world 2 weeks ago
I get all that, and maybe a size threshold would have been useful.
but the rule of “cleared its own orbit” is not only arbitrary, but time and orbit dependent.
you there could be another planet far away, which is likely a gas giant, and if discovered it would be obviously considered a planet. however we will never know for sure because we will never know if there’s another object in it’s orbit, and if we then discover another gas giant in its orbit (it would be so large it’s unlikely to have cleared its orbit), then we would have to demote two gas giants (or more) into a dwarf planet status.
which is so plainly ridiculous. just make a reasonable threshold between asteroid and planet based on mass. or even geology, if it’s just loosely bound rubble, its an astoroid, if it’s large enough to have geology of some sort, then a planet (although that would be harder to determine).
but just based on an extrinsic factor?
if eventually Ceres yeets pluto out, would Ceres become a legit planet?
why is a planetary object multiple AU away from the object you are studying determined wether something is a planet or a dwarf planet?
that’s like defining that hydrogen is no longer hydrogen if it is bound with another element.