Planet 9 Sour Grapes
Keith’s note: One planetary scientist is doing a systematic search for a large planet that may be lurking in the outermost reaches of our solar system. Meanwhile another planetary scientist who got his own mission to visit the farthest objects yet visited in our solar system just can’t get over a nomenclature decision made a decade ago.
@plutokiller @jccwrt Sorry bub. Tombaugh found the real planet 9 in 1930. Many more found since. Hope you find yours but You gotta get in line.
— AlanStern (@AlanStern) May 5, 2017
Thank you for this, guys. I had a really, really bad day today, and this got me laughing. Some people just can’t get over poor Pluto.
(holds his hand up) Yeah; me too…
I know I was just being a little humorous – but after the New Horizons encounter, I’m far from the only one who was stunned by the beauty, variety and sheer science of the Pluto system. It will always be a planet to me! :'(
Too bad that the person most associated with NH can’t let go of a silly argument and focus on Pluto for what it is: amazing.
Stern does both full throttle, IMO. I don’t think his throttle has any settings other than off and full.
There is also some inconsistency here. Since he’s the second author, I assume Stern agrees with the definition of a planet recently suggested by Runyon et al. earlier this year. https://www.hou.usra.edu/me…
That defines a planet as anything which is massive to be round from self-gravity and which isn’t a star. The authors note that this would include “at least 110 known planets in our Solar System.”
By that logic, the the seventh, eighth, ninth and tenth planets (in order of discovery) would be Io, Europa, Ganymede and Callisto. Or, in distance from the Sun, one of the larger asteroids would be the ninth planet. Even if you agree with this definition, Tombaugh did not find the real planet 9 in 1930.
Oh stop thinking logically 😉
And if you require the object be in orbit around the Sun, Pluto still wouldn’t be the 9th planet. Ceres was discovered in 1801.
Still wrong. Technically, the Moon does not orbit the Earth. Both “Planets” always fall towards the Sun, not each other so Earth-Moon is a Double Planet. This makes Ceres 10 and Pluto-Charon is a Double Planet as well which makes them 11-12!
The Moon is well inside Earth’s Hill Sphere, so it’s proper to consider it orbiting the Earth (with perturbations by the sun, of course.) However, you are right in the sense that the Moon is a traditional (pre-Copernican) planet.
Actually if you are listing in order of discovery…
Uranus – 1781 – 7th Planet
Ceres – 1801 – 8th Planet
Neptune – 1846 – 9th Planet
Pluto – 1930 – 10th Planet
I left out Pallas (1802) and Vesta (1807) because neither seems to be really round, but IF included Pallas would be the 9th Planet and Vesta would be the 10th Planet, pushing Neptune to the 11th Planet and Pluto to the 12th Planet.
If you accept Stern’s inclusion of moons as “planets” then…
Ganymede – 1610 – 8th or 9th Planet
Europa – 1610 – 8th or 9th Planet
Callisto – 1610 – 10th Planet
Io – 1610 – 11th Planet
Titan – 1655 – 12th Planet
Uranus – 1781 – 13th Planet
Titania – 1787… etc
(Counting our Moon as one of the seven planets of antiquity.)
I suggest find the planet first, then argue (if we must) about its name/number.
I’m just going to go with “major planets” for the eight and “minor planets” for the rest. Arbitrary label, but meh – we have tons of those (see continents).
P L U T O = Poor Little Undersized Transient Object
Oh, let’s rub it in a little more… Poor Little Undersized Triton-like Object.
What do we know about Mike Brown?
“Mike Brown is the Richard and Barbara Rosenberg Professor of Planetary Astronomy at the California Institute of Technology and has been on the faculty there since 1996. He specializes in the discovery and study of bodies at the edge of the solar system. Among his numerous scientific accomplishments, he is best known for his discovery of Eris, the most massive object found in the solar system in 150 years, and the object which led to the debate and eventual demotion of Pluto from a real planet to a dwarf planet. “
http://web.gps.caltech.edu/…
Stern referring to another PHD as “bub” … well childish to say the least and looks like he is holding a massive grudge.,,,
Planetary scientists tend to be a pretty informal group. I doubt Mike would get upset about the “bub” part. But the ongoing feud over Pluto’s taxonomy must get annoying at times.
Sounds like a gentle tease with a back story known only to the two of those guys.
I couldn’t find any back and forth on the feeds
Why would Griffin get upset .. he was the one making the comment. I didn’t see any back and forth among friends on the twitter feeds
Griffin? I was talking about Mike Brown. But I didn’t mean to imply Brown and Stern are friends. I have no idea (actually, I don’t think I’ve even run into Brown in person in the last fifteen years.) I just meant that planetary scientists do tend to address each other in very informal ways, without meaning anything by it.
It’s the content that can get rude, not the form of address. If I said, “Bob is all wrong: the data just aren’t good enough to support his claims.”, I’m confident “Bob” wouldn’t object to my using his first name. He might, on the other hand, be really upset about me trashing his analysis. (And, fortunately, “Bob” is a common enough name I can use that as an example without meaning anyone in particular.)
The Russians did that test .. so did America … I am sure the Chinese felt they are entitled to copy EXACTLY what the US and Russia do.
HEY!!!
Does Stern live inside such a bubble that he doesn’t realise how pathetic this stuff makes him look?
Stern does seem a little immature..one of those somewhat neerdy/geeky guys you really don’t want to know.
After discovering so many exoplanets, could we say who cares about some pieces of rocks lurking far from the sun? All these fights are about nothing.
Well, we can get surface images of those distant rocks at 50 m/pixel. It’s a bit hard to do geology of exoplanets.
I’m still waiting for someone to explain why you should consider Pluto a planet and not Charon. Or not consider Pluto and Charon twin Dwarfs.
I’m with Brett: major & minor (delineated perhaps by a certain mass threshold) planet seems a more elegant terminology; the ‘spherical shape’ should be covered by (perhaps) a lower mass threshold, below which the (likely but not necessarily non-spherical) object remains an asteroid, comet, or as-yet-specified body.
I can’t agree with the purely geomorphological definition of Runyon et al.; if it’s orbiting a star then it’s a planet, and if it’s orbiting a planet then it’s a moon. Free-ranging interstellar objects would get a pass and be accepted as…free-ranging planets, if they meet the mass threshold.
For ‘double-planet’ questions, the location of the barycenter should ‘draw the line’. If the barycenter is inside the surface boundary of the primary, the other object(s) is a moon. If it’s outside the primary, then the secondary is a planet.
I would be delighted to welcome/redesignate Ceres as planet nine and Pluto & Charon and planets 10 & 11. [Or is Vesta in that particular mix, too?]
I suspect that a large portion of Stern’s perceived ‘sour grapes’ has more to do with a dissatisfaction with the IAU’s poor definition (as their paper indicates, it does have serious flaws and really does need fixing given its sowing of lack of clarity) and the clumsy and arbitrary way it came to be, not with Dr. Brown.
This is why exact definitions can get messy and, perhaps, pointless.
When it comes to spherical shape versus a lower limit on mass, that’s got a problem because the shape depends on the internal structure as well as the mass. A very, very small object, composed of liquid water, could be spherical due to self-gravity. The same mass of frozen-solid, 100 deg K ice could have any shape you like. (Runyon et al. did, by the way, suggest that the shape requirement be a body which is well-approximated by a triaxial ellipse, not spherical. I like that, since most planets are oblate and not exactly spherical.)
For double planets, tidal evolution makes the barycenter definition a bit problematic. Unless something very, very strange happens, the Earth-Moon barycenter will always be 1.2% of the way from the Earth’s center to the Moon. But tidal forces cause the Moon’s orbit to migrate outward. Some time in the future, the Moon will be 40% farther from the Earth, and the Earth-Moon barycenter will be above the Earth’s surface. At that point, will the Moon have transformed from a moon to half of a binary planet system?
Re: Earth-Moon distance increase: Yes. And we can hold a graduation party when it happens.
You make good points. I would lean toward choosing mass over shape and let the chips fall where they may. I suspect we would end up with a ‘most of the time but there are exceptions’ circumstance; Nature often distributes like that.
Note that there is a very large mass difference between the smallest “major” planets in our solar system and Pluto or Eris or Charon. For many of us that is an important distinction, hence the usefulness of the term “dwarf planet”. What irritates is the part of the IAU definition that states, against all logic, that “a dwarf planet is not a planet”. This sentence was proposed as an amendment from the floor after most planetary scientists had left the IAU meeting, and it illustrates the perils of IAU procedures. In my text books I have called Pluto a dwarf planet but said that is just one kind of planet, like major or terrestrial planets.
That is unfair to your students. A) It makes them look stupid. B) It denies them an understanding of the significance of the definition of “planet”.
For example, the fact that the “9th planet” has only been hypothesised because of the influence it has on the orbits of surrounding TNOs is the very reason it will be considered a planet upon discovery. That’s what “planet” means.
You could use the distinction between planets and the larger non-planets to introduce an interesting part of modern astronomy. Instead you chose to misinform them.
[It’s the same with Stern himself. He came up with the “clearing the neighbourhood” language, and showed the distinction between the planets and non-planets. He could use the attention to expand the public awareness of gravitational dynamical dominance, but instead he chooses to lie about it and undermine other scientists and scientific institutions because he didn’t get his own way.]
It’s worth pointing out that that sentence was only added because Stern’s faction tried use “dwarf planet” to backdoor planetary status for Pluto. Responding with a 90+% vote for that sentence was an explicit rebuff to that group.
And I’m sick of this meme. Stern’s faction tried to ram through the “roundness” definition of planet early in the proceedings (using press releases to try to make it a fait accompli). They were rejected by over 90% of the assembly and forced to go back to the drawing board. That’s why the second round of voting was pushed back to the end.
[Aside: Would you, or Stern, be complaining about the number of voters if you’d gotten your way?]
If it had been even roughly close, you could argue that the IAU assembly was statistically non-representative. But with a 90+% overwhelming rejection of Stern’s preferred definition, there’s hardly any ambiguity. Nor has there been any widespread unrest amongst the rank-and-file members who weren’t attending, other than Stern’s team.
Personally I’d prefer if they hadn’t given that faction the sop of “dwarf planets” at all, and simply left Pluto, et al, as part of the definition for SSSBs. But this is what you get when you try to compromise with people who aren’t reasonable.
I don’t get it. Do you not agree that Pluto is a dwarf planet? And that the are many types of planets: Giant, terrestrial, dwarf, minor, free-floating, etc.?
[I suspect that I added to my comment after you last reloaded the thread. It won’t have appeared while you were typing. Reload the page and see if you want to add or change anything in your comment.]
Okay, continuing…
I agree that the IAU created the definition of “dwarf planet” which covers Pluto/Ceres/etc. I disagree with them doing so. I think it was unnecessary and Pluto/Ceres/etc should have been left as glorified asteroids, as part of the Small Solar System Bodies classification scheme. Put simply, it serves no useful scientific purpose.
There may be different types of planets, but “dwarf” is not one of them. There is a large distinction between the actual planets and the rest of the solar system, and “dwarfs” are on the non-planet side of that gap. (Stern’s own 2002 paper showed that. He called them “uber” and “unter”. Ie, above or below the line. Eight “uberplanets” and Pluto was an “unterplanet”.)
There are a few different proposed “determinants” to allow a scaling of objects, but they all leave a gap of several orders of magnitude between the least planet (Mars) and the highest ranking non-planet (either Pluto or Ceres, depending on the type of determinant you use.)
Even if you use a different system, the gap between planets and non-planets remains. It’s a real, naturally occurring, and important feature of the solar system. It tells you something about the structure and formation of the solar system.
And it’s useful to apply to exo-planets. Which means we’ll be able to do broad statistical analysis on the formation of thousands of planetary systems, being able to quickly identify the odd-balls for further study.
I feel major planet, minor planet, and asteroid/comet are acceptable as terms, with the distinction by mass alone. I think a minor planet can also be a moon if it orbits a larger planet, while if the center of rotation is not within the larger body, neither would be a moon, they would be considered a double planet. I don’t find the argument about clearing one’s orbit of other junk convincing.
Nature has no labels, and few boundaries. Science categorizes things and names them to help folks learn about them. Therefore, for individual scientists to get all huffy about the naming being wrong or right is just a little bit arrogant…and in the case of Stern, maybe just a little bit self-serving.
Based on the ancient definition of planet as a wondering star, Pluto is a planet…however, the ancients couldn’t see Pluto, therefore maybe it isn’t. We can go on and on. Pluto fits several technical categories and doesn’t fit some others (perhaps) as conveniently as some of us became accustomed to. If the folks who have naming rights over the word “planet” say that Pluto isn’t, then it damages the usefulness of the word for some to beat the dead horse over it. In some ways, it is easier to understand Pluto by calling it a Planet, in some ways it isn’t.
I for one liked calling it a planet, but have been calling it Dwarf Planet in my space exploration advocacy activities.
I was as wowed by those close-up shots of Pluto as everyone else. I picture myself walking on its surface. I WANT to call it a Planet…really bad…after seeing those images. But…it really does have more in common with Ceres than it does with Uranus.
However, nature has drawn a clear boundary between planets and non-planets of the solar system. That’s what led to the dynamical-dominance definition (“clearing the neighbourhood”), new understanding about the gravitational origins of the structure of the solar system.
Do you really think that there is a clear boundary there?
Is Mercury big enough to do that?
It’s not “think”, there simply is. It’s not a line, it’s a huge gap.
Dynamical dominance (the ability of a planet to clear or control its region) is a combination of the mass of the planet, the mass of the primary star, and the distance between the planet and the primary.
Here’s a paper co-written by Alan Stern in 2000: http://www.boulder.swri.edu…
And an updated paper by Jean-Luc Margot in 2015: https://arxiv.org/pdf/1507….
Using Stern-Levison’s own planetary criteria:
https://uploads.disquscdn.c…
Using Margot’s determinant:
https://uploads.disquscdn.c…
—
Stern’s paper is one of the reasons why his public statements annoy me so much. He knows what the terminology means, he knows the distinction between planets and non-planets (he used the terms “uber-planets” (for the 8) and “unter-planets” (for everything else)) and he knows the reason for that distinction. When he publicly pretends to “misunderstand” the IAU definition, he is lying. And I find it pathetic.
[His paper contains the line: “Occasionally, the debate looked more like one between religious fanatics than scientists.” But he doesn’t see the enormous irony in his manipulative and obsessive behaviour.]
He’s been talking that way ever since the flyby, and I didn’t know about that 2000 paper.
He’s been talking that way ever since the flyby.
We all got pretty excited about the sort-of-Earthly look of those photos.
I think Stern understands the dynamical criteria very well. He doesn’t, for one reason or another, agree that it is relevant. Personally, I don’t like it because it is motivated by current (or somewhat less than current) theories of planetary formation. If the theories turn out to be wrong, the definition would become pointless and possibly counterproductive.
If the Grand Tack actually happened, is the Earth’s ability to clear its orbital region relevant? Since there is a time scale involved (the age of the solar system), is the dynamical criteria appropriate for extrasolar planets? I.e. if it is a young system and an exoplanet has not yet cleared its orbital zone but will eventually do so? Do we hold a coming out party, now that it’s old enough to play with grown-up​ planets? I’d prefer definitions that depend on observations more than theory.
Then why does he lie about it?
The distinction between the eight planets and the non-planets in the solar system is based on observation.