The only reason Pluto is no longer a planet is because we discovered there were loads more planets and couldn’t be bothered to acknowledge their existence!
i’ve spent 25 years on this blue marble fascinated by space, and only recently discovered there multiple long orbit dwarf planets going around the sun??? that is so cool why is this not widely known!
we used to have a handful of elements, but when we kept discovering more, we didn’t change the rules to have elements, and “strange elements” so schools only have to teach about 16 elements.
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.
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of “classical planets”, so we can have posters, or have like periodic tables, and everyone be aware that they might go out of date as more is discoverd.
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.
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.
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.
I think the rule of “cleared its own orbit” tried to be less arbitrary and failed horribly.
A size threshold is clearly more consistent, but it’s purely arbitrary, while the “cleared its own orbit” rule at least has the appearence of not being totally arbitrary, even though it introduces just the problem you are describing.
The only reason Pluto is no longer a planet is because we discovered there were loads more planets and couldn’t be bothered to acknowledge their existence!
It’s been like that for decades to be honest. Ceres used to be called a planet, but you don’t see anyone complaining about it’s demotion
i’ve spent 25 years on this blue marble fascinated by space, and only recently discovered there multiple long orbit dwarf planets going around the sun??? that is so cool why is this not widely known!
Well, it is widely know.
Unpopular opinion: dwarf planets are cool.
but so what?
we used to have a handful of elements, but when we kept discovering more, we didn’t change the rules to have elements, and “strange elements” so schools only have to teach about 16 elements.
It’s all just made up categorization. It’s like that because astronomers have agreed to categorize them like that. That’s all.
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.
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 discoverd.
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.
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.
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.
I totally get your point.
I think the rule of “cleared its own orbit” tried to be less arbitrary and failed horribly.
A size threshold is clearly more consistent, but it’s purely arbitrary, while the “cleared its own orbit” rule at least has the appearence of not being totally arbitrary, even though it introduces just the problem you are describing.
it’s fine to place arbitrary separations in a spectrum as long as we are aware it’s a spectrum.
but it’s also annoying that “dwarf” implies smaller, and as I said before, we could have gas giants that could be classified as a dwarf planets.
and without a doubt there are exoplanets that are gas giants but also dwarf.
which is just plain stupid.