From what I understand, the primary reason Pluto had to be re-classified is because we found thousands of similar planets. So it's either remove one planet from the list we teach preschoolers, or add thousands more. It all seems a bit pedantic to me either way, personally.

This pointless culture war brought to us by the same people who renamed the Gulf of Mexico to the "Gulf of America" so they could be angry on Twitter about it.

Perhaps the NASA administrator should be more worried about how Trump is destroying employee morale with his anti-science agenda.

Not thousands, but if Pluto is a planet then you have to argue that Ceres (the largest of the asteroids) also is. It’s large enough so that its own gravity has formed it in to a sphere (almost), and orbits the Sun. Eris, certainly has to be a planet, although slightly smaller than Pluto it is, from memory, about 25% more massive, and even has its own moon.

I think there are five or six, known objects that a) orbit the sun, b) are massive enough to form a sphere, but c) are not massive enough to have cleared their orbits, usually by repeated gravitational action ejecting the other objects out of their orbit. However it is not impossible that eventually a thousand objects of Pluto’s size might eventually be discovered in the Kuiper belt - and who knows what might be lurking in the Oort cloud?

Does the nomenclature 'planet' serve any actual scientific benefit?

If not then I propose we just drop the word and be done with it. We can then say 'our sun is orbited by many different size objects some of which primarily orbit other objects'.

I doubt that the universe cares how we choose to categorise things - is there a reason we have to categorise rocks and stuff in space?

Vogons?

Tomatoes are a fruit, but we still call them a vegetable…

Cleared orbit

The exact same argument can be made for Neptune, so either restore Pluto or demote Neptune. Since is it obvious to anybody with any sense (which may exclude international committees) that Neptune really is a planet, then Pluto should be considered one too.

Re: Cleared orbit

Neptune cleared its orbit. Pluto did not.

This distinction is lost on Trump supporters, who aren't exactly known for their understanding of science.

Re: Cleared orbit

The orbits of Neptune and Pluto overlap. How can one be cleared and the other not?

Re: Cleared orbit

All of the orbit needs to be cleared not just the overlap

Re: Cleared orbit

That's not what it means to [1]clear an orbit .

There aren't nine planets in the solar system. The definition is meant to be useful to astronomers, which allows for eight. If Pluto is classified as a planet, then there are potentially hundreds of other objects which would have to be classified similarly, which thus makes the definition useless. Hence, why astronomers draw a clear line between planets, dwarf planets, and other objects.

[1] https://www.rmg.co.uk/stories/space-astronomy/dwarf-planets-pluto-ceres-haumea-makemake-eris

Re: Cleared orbit

Geologists, on the other hand, don't give two shits about *where* the object is. They only care about *what* the object is, so having separate names for Pluto, Io and Earth is just a load of nonsense pushed by the telescope jockeys. It isn't real science.

Re: Cleared orbit

Distinct classifications for distinct classes of objects makes for greater clarity. All fields of science do it.

New scientific discoveries often lead to new terminology. Calling Pluto a planet when it was discovered made sense then. Now, thanks to more discoveries, classifying it as a dwarf planet makes more sense. Pluto isn't like our system's eight planets, but it shouldn't be classified as an asteroid, either.

Astronomers make a useful distinction between terrestrial planets and gas giants. Eventually, as we learned more, it made sense to draw a distinction between gas giants and ice giants.

Re: Cleared orbit

I remember when there were only five vowels. A, E, I, O, and U. And then someone discovered 'Y'.

Re: Cleared orbit

Neptune and Pluto are in a resonance, so actually in a very real sense their orbits do *not* overlap, and never will.

Re: Cleared orbit

Also their orbital inclination is vastly different. And their orbital periods are in resonance so they can never actually get close to each other, even if, yes technically Pluto can get closer to the sun than Neptune does, which, from memory, I think it was until 1999.

But this doesn't mean that the orbits cross.

Re: Cleared orbit

Grow up & leave your TDS outside of any Technical discussion !

Re: Cleared orbit

If you want technical discussion, then leave Trumpism out completely.

I don't care what some idiot in a red hat thinks about the definition of "planet."

Re: Cleared orbit

Neptune long, long ago cleared its orbit.

At worst, the reclassification of Pluto is a squabble between planetary astronomers who had been discovering many new dwarf planets, and other astronomers who had concerns that were less cogent (“But we’ve been teaching kids for decades there are nine planets!”). It’s solely about nomenclature.

I had the privilege to meet Mr. Tombaugh 37 years ago at an American Astronomical Society meeting. I frankly don’t’ think he would have been upset by the decision. I don’t think we need a NASA Administrator, whose experience is as an entrepreneur who enjoys his wealth by cosplaying jet jockey and astronaut and being lobbied by Dr. Stern, to waste his time on such things.

Re: Cleared orbit

Fun fact, a small sample of Tombaugh’s ashes were placed on the New Horizon’s probe. Which means he is the only person to have discovered a planet/dwarf planet and actually visited it. Well sort of.

Could the fact that Pluto was the only planet of our solar system discovered by an American have anything to do with this?

Bigly.

exoplanets

There were good arguments for demoting Pluto, not least that Eris is more massive.

However, it did strike me at the time that it was a strange moment to try to define what a planet is, just as thousands of them started to be discovered in very different systems.

Re: exoplanets

That was exactly why they chose that moment. WTF were we to call all these feckin' new thingies, mixed up in one belt of crap or another? It was getting out of hand.

Re: exoplanets

That's like saying that someone who lives in the Arctic should fix their definitions of "plant" and "animal" before going to explore the Tropics.

Re: exoplanets

Suppose someone does have clear definitions of "plant" and "animal"

What should they do upon encountering a mushroom?

Re: exoplanets

Take him out for a beer, he's a fun guy to be with.

This is stupid anti science MAGA trolling

They might couch it in other ways but anything that devalues the work of "experts" (like the ones who reclassified Pluto) is red meat for the red hat wearing morons who hate having experts who have been educated in and studied the field for decades tell them anything what they heard from some rando on Youtube, whether it is "Pluto is not a planet" or "mRNA vaccines are not dangerous".

I'm sure science can survive a honorary planet membership that is grandfathered in.

But that's not science.

Cynical scientists quip that science advances, one funeral at a time, because that's not how it's supposed to work.

At the time..

the debate was whether to have eight planets or twelve--Charon, Eris, and Ceres being the planet candidates that "forced" the issue.

It is important to note that the designation "dwarf planet" was a compromise designation originating at the 2006 IAU conference. There was no awareness in the public of the issue. Of course, the notion that the general public can be involved with scientific debate is silly, but Pluto being a planet was (and mostly still is) part of the general public consciousness. As a result, this change in designation went over about as well as cross between New Coke and the metric system (in the US).

Personally, I can fully understand the need for the change. Ideally, this change could be taught as an example of how science actually works. But grade school children are not ready for that, which gets us straight into the cultural problem of the change. Junior comes home from school saying that there are eight planets, and their parents lose faith in the school system and maybe science itself.

Personally, I think we might be better off saying that there are nine planets up until high school, then, in high school physics, talk about dwarf planets as part of how the science works in the real world.

Re: At the time..

Junior should listen to his science teacher. We wouldn't be having this problem if most parents hadn't gotten their science PhDs at the University of Facebook.

Junior should also be learning about things like the metric system, evolution, and vaccines.

We send the wrong message about science when we say the quest for truth has to compromise with dumb people who cling to outdated cultural tropes.

Hence why the US still trips itself up using moron units, because politicians and influencers have taught Americans to hate the metric system, and wonder what the plot is, which is obviously way too communist and French for real, freedom-luvin' Americans.

Re: At the time..

the issue is that we want to have strict definitions with clear distinctions between what is and what is therefore not within the definition. But the Universe is very complicated and often produces examples that do not fit in with our conceived notions of what is possible.

The word 'planet' is derived from a term meaning 'wanderer' as they were originally stars that wandered about the sky and this distinguished them from the 'fixed stars'. Pluto is definitely a 'wanderer', but whether it is technically a 'dwarf' wanderer is for others to determine, not me, but I would like to know what scientific difference it makes.

Jared, Jerry, sounds kinda similar...

Scroopy Noopers will NOT be happy about this nonsense.

If Pluto is a planet...

...then so too should be Ceres. Those beltalowdas deserve a little bit of respect.

Re: If Pluto is a planet...

Then so should Eris! What, the protomolecule doesn't deserve respect?

It had to clear the neighborhood around its orbit – nope …

Just like to point out that there are something like ten thousand Near Earth Objects, so by that definition, Planet Earth technically fails to qualify as a proper planet.

Which shows that trying to create a strict definition of what is and isn't a planet will fall apart the moment it encounters that vague and messy thing called reality.