58 days, 11 hours, 59 minutes until our Once and Future President, the Rightful President of the United States, is restored to his proper office.

Not that I’m counting, mind you.

[Assumes 0001 publication time. Wordpiss will be wordpiss and it’s unlikely to happen at that time.]

What is it that feeds our battle, yet starves our victory?

Speaker Johnson: A Reminder.

And MTG is there to help make it stick.

January 6 tapes. A good start…but then nothing.

Were you just hoping we’d be distracted by the first set and not notice?

Are you THAT kind of “Republican”?

Are you Kevin McCarthy lite?

What are you waiting for?

I have a personal interest in this issue.

And if you aren’t…what the hell is wrong with you?

Lawyer Appeasement Section

OK now for the fine print.

This is the WQTH Daily Thread. You know the drill. There’s no Poltical correctness, but civility is a requirement. There are Important Guidelines,  here, with an addendum on 20191110.

We have a new board – called The U Tree – where people can take each other to the woodshed without fear of censorship or moderation.

And remember Wheatie’s Rules:

1. No food fights
2. No running with scissors.
3. If you bring snacks, bring enough for everyone.
4. Zeroth rule of gun safety: Don’t let the government get your guns.
5. Rule one of gun safety: The gun is always loaded.
5a. If you actually want the gun to be loaded, like because you’re checking out a bump in the night, then it’s empty.
6. Rule two of gun safety: Never point the gun at anything you’re not willing to destroy.
7. Rule three: Keep your finger off the trigger until ready to fire.
8. Rule the fourth: Be sure of your target and what is behind it.

(Hmm a few extras seem to have crept in.)

Spot (i.e., paper) Prices

Last week:

Gold $2,563.30
Silver $30.30
Platinum $947.00
Palladium $974.00
Rhodium $4,950.00
FRNSI* 123.000-
Gold:Silver 84.597+

This week, 3PM Mountain Time, Kitco “ask” prices. Markets have closed for the weekend.

Gold $2,716.90
Silver $31.41
Platinum $973.00
Palladium $1,034.00
Rhodium $4,950.00
FRNSI* 130.430+
Gold:Silver 86.498-

The attention is on gold. It has recovered over $150 of the losses it took right after the election, just since last Friday. Alas, silver has not kept up, and the gold:silver ratio has gone up almost two points. Platinum still struggles to climb out of the gutter, while palladium seems more dynamic. Rhodium did move around a bit, but ended up where it was last Friday.

*The SteveInCO Federal Reserve Note Suckage Index (FRNSI) is a measure of how much the dollar has inflated. It’s the ratio of the current price of gold, to the number of dollars an ounce of fine gold made up when the dollar was defined as 25.8 grains of 0.900 gold. That worked out to an ounce being $20.67+71/387 of a cent. (Note gold wasn’t worth this much back then, thus much gold was $20.67 71/387ths. It’s a subtle distinction. One ounce of gold wasn’t worth $20.67 back then, it was $20.67.) Once this ratio is computed, 1 is subtracted from it so that the number is zero when the dollar is at its proper value, indicating zero suckage.

Reminder: Most Flat Earther Influencers are Liars

Most Flat Earther influencers like Flat Earth Dave and Eric Dubay have said for years that they want to go to Antarctica during southern summer and watch the Sun set…which would prove the globe model isn’t right. The globe model not only predicts the Sun will not set in Antarctica at and around the solstice, it predicts the Sun’s path through the sky will circle the observer over the course of a 24 hour day, going from north to west to south to east of the observer. (At the south pole itself, some of those directions are meaningless since every direction is north; but just move a millimeter from the pole and they mean something.)

They’ve been given the chance to go to Antarctica for free and now all of the sudden refuse to do it; they are even ostracizing the few among their number who have agreed to take the trip, accusing them of having sold out and being shills in advance of them coming back and reporting what they have seen,

That should be enough to tell any reasonable observer that they already know what the travelers to Antarctica will see…and it won’t be good for Flat Earth. Which is why I am not calling them ignorant or deluded; I am calling them liars. They know the Earth is not flat, yet they make a shitload of money claiming it is.

Lying. Sacks. Of. Shit.

However, I don’t call all of them liars. I give some praise to those few who are going; they apparently do actually believe it (which is not good on them)–negating the “liar” aspect–but more importantly they have the intellectual courage to test their beliefs, even in the face of ostracism from the knowing con-men on their side.

Beyond Neptune

Of course everyone knows what’s after Neptune.

Pluto.

But that’s not all of the story by any means.

The Discovery of Pluto

I told the story last time of the discovery of Neptune. But as astronomers observed and tracked Neptune in the last half of the 19th century, it appeared that Neptune didn’t account for all of Uranus’s unexpected motions.

The first thought, of course, is that there’s yet another planet out there. Percival Lowell decided to try to do something about it beyond thinking.

Percival Lowell had founded the Lowell observatory near Flagstaff, AZ in 1894, largely to observe Mars, but in 1906 he started searching for Planet Nine. He kept on looking with the help of William H. Pickering, using calculations by Elizabeth Williams. Nothing was found and Lowell passed away in 1916. (As it turns out his photographic plates did have “hits” on Pluto for March 19 and April 7th, 1915, but they were faint and didn’t get noticed. Planet Nine was expected to be big. There are fourteen other known instances of Pluto showing up, unrecognized, on observatories’ photographic plates from 1909 on; these are called “precovery” photographs.)

Percival Lowell’s widow, Constance, got into a ten year legal battle with the observatory, so the search stopped. But once the legal cloud had cleared, the director, Vesto Melvin Slipher (the first to see redshifts in galaxies) gave 23 year old Clyde Tombaugh the job of resuming the search. Tombaugh’s method consisted of taking photographs of the same area of the night sky a few days apart and putting the photographs (which were on glass plates) in a blink comparator, which would project one plate, then the other, and repeat. Any object that had moved in the meantime would seem to jump back and forth.

On February 18, 1930, Tombaugh spotted something on plates from the 23rd and 29th of January.

As you can see, the photographs were often not exposed to the same brightness, so anyone using a blink comparator would have to deal with the image getting brighter and dimmer, brighter and dimmer…while looking for the one object that was completely not there (not just dimmer) in one photograph or the other. (And it seems as though many things in the left photograph are not visible in the right hand photobraph. So perhaps Tombaugh simply looked for something that showed in the faint photo on the right, but not the brighter one on the left.)

A lower quality photo from the 21st helped confirm that Tombaugh wasn’t just seeing spots in front of his eyes. The observatory took more photos over the next few weeks to really nail the case down. Finally, on March 13, they telegraphed Harvard Observatory with the news.

The new planet orbits the Sun in 247.94 years, in an inclined and eccentric orbit. That period puts it into a 2:3 resonance with Neptune; it orbits twice in the amount of time it takes Neptune to orbit three times.

What to name it? They got thousands of suggestions, including Minerva, Pluto, and Cronus. Minerva had been used for an asteroid already, Cronus was being pushed by someone who was both unpopular and egocentric…so Pluto it was. (Cronus is also the Greek name for the titan who fathered Zeus and other Olympian gods…in other words it’s the Greek counterpart of the Roman Saturn.) Pluto/Hades was the god of the underworld. As a bonus, the first two letters are Percival Lowell’s initials. The name was approved by both the American Astronomical Society and the Royal Astonomical Society and the name became fixed on May 1. No jacking around with the name as had happened with Uranus for decades.

But right off the bat something didn’t add up.

One estimate from 1915 was that Planet Nine would have to be seven times as massive as the Earth. But a very early estimate after Pluto had been found, in 1931, had its mass as low as Earth’s (so, too low by a factor of 7). As more and more estimates were made over the years, Pluto’s estimated mass kept dropping; in 1948 Kuiper estimated it at 0.1 Earth masses, in 1976 it was lowered again to 0.01 Earth masses. But these were guesses based on Pluto’s size, which was estimated from how bright it was. It was never more than a dot of light on a photographic plate or film.

In 1978, we discovered Pluto had a moon, Charon…and with a moon we could determine the mass quite solidly, so the estimate dropped to 0.0015 Earth masses. And the latest number from 2006 is 0.00218 Earth masses. (I actually remember this happening. And now Pluto has five known moons.)

Charon, by the way, is the last of the medium-sized moons. Saturn has four, Uranus has four…and Pluto has one.

And we finally nailed down Pluto’s size, 2377 km in diameter. Our own moon is 3475 km across, and there are other moons larger than it. Mercury is also far larger than Pluto.

This is just way too tiny to be the planet we were looking for.

Furthermore, Voyager 2 in 1989 caused the estimates for Neptune’s mass to be dropped 0.5% and the “remaining discrepancy” in Uranus’s orbit now disappeared; Neptune accounted for it all.

So Pluto’s discovery was ultimately a stroke of luck. We were groping around in a dark room with a blindfold on, looking for a cat that wasn’t there…but we had found the mouse that was.

But now, just about everything about Pluto (and not just its size) made many wonder if it really should be considered a planet. Pluto is in a very un-planetery orbit. The other eight planets had reasonably circular orbits (Mercury being a bit of an outlier) all in nearly the same plane: the ecliptic (which is defined by the plane of Earth’s orbit). Pluto’s orbit is inclined 17 degrees to the ecliptic; no other planet came anywhere close to that. Furthermore, its orbit was very eccentric, not circular (e=.2488). In fact, with a semi-major axis of 39.482, that meant Pluto’s closest approach to the Sun was 29.658 AU.

That’s closer than Neptune. Pluto was actually at that point on September 5, 1989. For the entire twenty year period from 1979-1999 Pluto wasn’t the outermost planet, Neptune was.

[DIGRESSION: There is, by the way, little to no danger of a collision between Neptune and Pluto. If you look at the two orbits in 3D it becomes apparent that Pluto crosses the plane of Neptune’s orbit pretty far away from the actual orbit of Neptune. Here’s an animation of one Plutonian year from an oblique angle. The vertical white lines show how far below or above the plane Pluto is at any given time.

You can watch the animation and note that Neptune is at about 4 o’clock in the diagram at the start of the animation, and that’s where Pluto is furthest from the Sun. At the end of the animation, Neptune is at 10 o’clock; in other words it has orbited 1 1/2 times while Pluto orbited once (that’s a 3:2 resonance). At no point will the two planets come near each other, and since this pattern repeats, they won’t ever unless something causes an orbit to change.]

END OF DIGRESSION and back to the main thread: So Pluto didn’t look like any other planet. Nor did it act like any other planet. But if Pluto were all there was out there, most people would go ahead and consider it a planet.

But as it happens. there’s quite a lot “out there.”

The Centaurs

In 1977, Charles Kowal discovered Chiron, an asteroid, roughly 200 km across…but one with a difference. It was nowhere near the asteroid belt; it was well outside of it. That was a first, and barely a hint of things to come. Chiron is named after a centaur; and we would discover more such bodies. There’s a whole class of them now and that class is called the “centaurs.” It turned out there were “precovery” images of Chiron going clear back to 1895. And it turns out to have a ring!

There is a registry of so-called minor planets. When there is an initial observation, they’re given a “provisional designation.” (The scheme is a bit complicated: https://en.wikipedia.org/wiki/Provisional_designation_in_astronomy#Minor_planets but the first part is obviously the year of the first observation). Sometimes it gets an unofficial nickname, if it’s particularly interesting. Once we have enough data to establish an orbit, the object is given a number in the order they are discovered–and sometimes it gets a name too. (There are hundreds of thousands of objects that never got past the provisional designation stage.) Minor planets are simply numbered in order: Ceres is formally “1 Ceres”, then there is 2 Pallas, 3 Vesta, 4 Juno, and so on. It used to be just asteroids, but as we will see a lot more different kinds of things are on the list. These objects have the following in common: they orbit the sun directly, but aren’t planets, and aren’t comets.

[WARNING: Have a barf bucket handy for this one: Believe it or not there’s an object nicknamed (but not permanently named) “Biden,” provisional number 2012 VP₁₁₃. And it got that name because Biden was the VP that year. However it’s been 12 years and they weren’t able to verify it so it might not be a real minor planet, in much the same way that Biden today isn’t a real president.]

When Chiron was first discovered, it got the provisional designation “1977 UB.” Once its orbit was established, it was regarded as the 2060th “minor planet” to be discovered, and now it’s formally known as 2060 Chiron. There are now over 44,000 known centaurs. And it’s speculated that Saturn’s way-out-there ninth moon, Phoebe, is a captured centaur. In general centaurs are far too likely to encounter one of the outer planets and so their orbits are not considered stable in the long term.

Buried in Planets?

Fifteen years later, things started to get crazy. We started finding more and more stuff way out there. The first was 15760 Albion (provisional designation 1992 QB₁).

Here is 15760 Albion’s orbit (it’s a very slo-mo gif, so you’re not seeing things, it does move). It is in a roughly 291 year orbit. Shown in red are the orbits of Jupiter, Saturn, Uranus and Neptune.

It actually looks like a planet’s orbit; it’s even spaced about right. Unfortunately, it was only a bit over 100km across, not even remotely big enough to have forced itself into a round shape. Not a planet.

A concerted effort was made to scan the entire ecliptic for very slow moving dots of light, to see if there were other things out there.

And there sure were. Lots of small stuff. But then we started finding big ones too, ones big enough to be rounded, and many, if not most, of these objects have moons!

In 2002, we found 50000 Quaoar (named after a deity worshiped by an Indian tribe that lived in what is now the LA area), orbiting between 41.9 and 45.5 AUs, in 289 years. Its diameter is 1,090 km. OK, that’s sizeable enough to get one’s attention! And it has a moon.

Then we found 90377 Sedna, discovered in 2003, which has a gigantic 506 AU (that is not a typo, yes five hundred and six astronomical units) orbit (that is 76 billion kilometers). That’s the semi-major axis (half way across the long way). This one is a highly eccentric orbit, so it’s not that far away from us at the moment; if it was we’d never be able to see it. Right now Sedna is 83.5 AU away (still twice as far as Pluto), near its nearest approach to the Sun at 76 AU. Its furthest distance is 937 AU! But be prepared to wait a while for it to get there. Its year is 11,400 of ours, and you’ll have to wait about half that long for it to get halfway around its orbit. So far as we know, Sedna does not have a moon. We can see no detail at that ridiculous distance, but it is colored distinctly red (my guess: tholins). And Sedna is very roughly 900 km across, which is again sizeable, not dismissable as a piece of rubble. Sedna does not have a moon that we can see, which as you will see is unusual.

In 2004 we found 90482 Orcus, 900 km or so in diameter, 30.3 to 48.1 AUs out orbiting in 245.1 years (almost exactly the same as Pluto). Also, it has a moon.

OK, this is starting to get ridiculous. But we’re just getting started!

Also in 2004, there is 136108 Haumea, announced a year later and its status not fully settled even then because…well because it’s 2000km across! That’s getting close to Pluto’s size. (As a side note, Haumea is distinctly rugby-ball shaped. We think. Again we don’t see much more than blobs in our images.) And (wait for it), it has two moons.

But the absolute, oh-shit-we-have-a-problem-here discovery was announced the very next year, 2005, based on observations from late 2003 and later. 2003 UB₃₁₃ was more massive than Pluto, though it appears to have a smaller diameter. The new object was “nicknamed” Xena (as in the Warrior Princess), and it took a while to settle on a permanent name. It turns out to have a moon, nicknamed Gabrielle after Xena’s sidekick. “Xena” orbits between 38.3 and 97.5 AUs, in 559 years. This object was actually announced by some YSM outlets as the tenth planet! Well, why not? If Pluto is a planet, this object certainly should be!

Because some people argued that indeed it was a planet, it took a while to get a permanent name and number. Why give it a number and have it turn out to not belong on the minor planet list? So “Xena” had to wait, for we were fully embroiled in discord.

And just for icing on the cake, on the same day that “Xena” was announced, the discovery of what would eventually be called 136472 Makemake was announced…and that was just two days after Haumea was announced. 136472 Makemake orbits between 38.1 and 52.8 AUs in 306 years.

Well. What a mess. Are they planets? We’d better figure this out because we’re getting buried here.

Rounding Up the Trans Neptunian Objects

I’m going to jump ahead here, a tiny bit. I’ll get back to the planet question soon.

I’m going to discuss the classification system we use today for these objects so (non-spoiler spoiler alert) Pluto will here be treated as one of these objects, not as a planet.

These objects all live beyond Neptune. But astronomers like to group things (you saw that with the moons of the gas and ice giants) and these objects, plus the zillions of much smaller ones in similar places that I haven’t mentioned, ultimately got “bucketed” into categories.

The Big Bucket is “trans-Neptunian object” Other than the centaurs, all of the objects I’ve discussed this time are trans-Neptunian objects (generally abbreviated “TNOs”), because they’re minor bodies outside of the orbit of Neptune.

But then we have sub-categories. The “Kuiper Belt” is those objects between 30 and 55 AUs from the Sun (as a reminder, Neptune is at roughly 30 AU). There are thousands of known Kuiper Belt objects, and the best estimate is that there are over a hundred thousand objects here over 100km in diameter. In fact there is far more “stuff” out there than in the asteroid belt. However, asteroid belt objects are typically rocks or metals, while the Kuiper Belt is mostly volatiles–iceballs, with some rocks in them.

The Kuiper Belt in turn has three classes of objects. The “classical” Kuiper Belt objects (cubewanos) are in reasonably circular, “regular” orbits, like Albion. There are a bunch in 2:3 resonance with Neptune (like Pluto), called plutinos, and others in a 1:2 resonance with Neptune, called twotinos. Orcus, Pluto, Haumea, Quaoar and Makemake are all Kuiper Belt objects. Orcus and Pluto are plutinos, the others are cubewanos.

This leaves Sedna and “Xena” unaccounted for. The other major category besides Kuiper Belt Objects is the “Scattered Disk Objects”, irregular-orbiting objects well beyond the Kuiper belt. “Xena” and Sedna fit here.

Here’s a handy-dandy chart. Or a confusing one, depending on your point of view, showing these categories, as well as the centaurs. In red across the top you will note designations like 2|3 and 1|2 for resonances with Neptune. And, oh by the way, Sedna is such an outlier it’s off the right hand edge of the diagram.

Gerard Peter Kuiper

Gerard Peter Kuiper, 1905-1973 (photo from 1964), was a Dutch-American astronomer. Americans trying to pronounce his name butcher it as “KAI-per,” rhyming with “piper.” The original Dutch pronunciation is indescribable to us except with the international phonetic alphabet: ˈɣɛrɪt ˈpitər ˈkœypər. He was the doctoral adviser for Carl Sagan, discovered Miranda (smallest moon of Uranus) and Nereid (third largest moon of Neptune), carbon dioxide in the atmosphere of Mars, and Titan’s atmosphere. He speculated that a large disk of of ices had condensed into smaller bodies, but would long since have been disrupted by Pluto (which was thought at the time to be massive). Well, he was half right; because Pluto is puny the objects are still there and the belt containing them is now named the Kuiper belt in his honor.

Discord

OK, back to “Are these planets?” The year is 2006. New Horizons launched on its mission to Pluto on 19 January of that year, and now it was time to evaluate the matter of whether it was on its way to a planet or not.

There was no formal definition of a planet. We knew them when we saw them. Except now we didn’t. Or rather everyone knew, but not the same as other people.

Alan Stern was (and still is) a principal investigator of the New Horizons probe (i.e., he is in charge of one of the instruments on that probe). Stern’s resume in the space program is as long as my arm. Time magazine even named him one of the 100 most influential people in 2007.

Stern was, and still is, an adamant defender of Pluto as a planet…and yes, he knows that means all these other objects, plus more to be discovered in the future, would be planets too.

His proposal: Divide planets into three subcategories. First, the classical planets, Mercury through Neptune, eight total. Then dwarf planets; that would include all of these big TNOs including Pluto, and Ceres, the largest object in the asteroid belt. The third category, though, is the “satellite planet.” These are the round moons orbiting other objects: our Moon, the four Galilean satellites of Jupiter, the seven round moons of Saturn, the five round moons of Uranus, Triton orbiting Neptune, and Charon orbiting Pluto.

These would all be planets, because they are massive enough for their gravity to have forced them into round shapes. (And this is one reason I’ve made a big deal about round versus not round.)

Including the moons seems a bit odd. But Stern’s position is very straightforward. He cares about the intrinsic properties of the object (it’s size and shape) first and its extrinsic circumstances, i.e. what orbit it’s in, second. If the object is round, it’s a planet, whether it dominates its orbit, or even if it orbits something else. Once it’s settled as a planet, then you decide whether it’s also a satellite, or big enough to “own” its orbit, and put it in the appropriate sub-buckets.

The IAU Makes Sausage

When the International Astronomical Union met in August of 2006 this matter was on the agenda and…well, we know the story. Alan Stern lost.

There is an aphorism that, like sausages, those that love law should not watch it being made. And that’s apparently true here as well.

The first proposal was: “A planet is a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet.”

In addition to the then-nine objects recognized as planets, this would have added Ceres, “Xena,” and Charon, the moon of Pluto. So we would immediately have twelve planets. In addition to this there were twelve candidate objects (including three asteroid-belt objects) that would likely fit once we knew more about them (including many of the ones I’ve talked about). Indeed there were claims (by Mike Brown who discovered Sedna and “Xena”) that we could have fifty three additional planets added almost immediately to this list of 12, and likely many more, perhaps 200, once we looked for more objects.

You may wonder why Charon would make the list, even though it’s fairly small as such things go. Why Charon and not Ganymede? That is because Charon and Pluto are close enough in size that the center of gravity of the Pluto-Charon system is actually outside of Pluto, unlike with every other moon in the solar system. That caused many to regard Pluto/Charon as a double planet…which of course would make Charon a planet.

Anything not spherical would be “bucketed” into Small Solar System Bodies (SSSBs). In addition, the “pluton” class (named for Pluto) would be used for things with highly eccentric or inclined objects. So this proposal drew one fairly clean line, if it’s round (and it’s not a star) it’s a planet, otherwise it’s an SSSB.

Although the relevant committee endorsed this, most of the IAU didn’t like this proposal; it was too ambiguous distinguishing between classical and dwarf planets. It failed a straw poll, 18-50 of a subgroup of the IAU.

So the second try, proposed by Gonzalo Tancredi and Julio Angel Fernandez:

(1) A planet is a celestial body that (a) is by far the largest object in its local population[1], (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [2], and (c) does not produce energy by any nuclear fusion mechanism [3].

(2) According to point (1), the eight classical planets discovered before 1900, which move in nearly circular orbits close to the ecliptic plane, are the only planets of the Solar System. All the other objects in orbit around the Sun are smaller than Mercury. We recognize that there are objects that fulfill the criteria (b) and (c) but not criterion (a). Those objects are defined as “dwarf” planets. Ceres, as well as Pluto and several other large Trans-Neptunian objects, belongs to this category. In contrast to the planets, these objects typically have highly inclined orbits and/or large eccentricities.

(3) All the other natural objects orbiting the Sun that do not fulfill any of the previous criteria shall be referred to collectively as “Small Solar System Bodies“.[4]

Definitions and clarifications

1. The local population is the collection of objects that cross or closely approach the orbit of the body in consideration.
2. This generally applies to objects with sizes above several hundred kilometers, depending on the material strength.
3. This criterion allows the distinction between gas giant planets and brown dwarfs or stars.
4. This class currently includes most of the Solar System asteroids, Near-Earth objects (NEOs), Mars-, Jupiter- and Neptune-Trojan asteroids, most Centaurs, most Trans-Neptunian Objects (TNOs), and comets.^[32]

This would have demoted Pluto to a “dwarf planet” which, despite the name including the word “planet,” was not a subcategory of planet; a difference between this and Stern’s proposal.

This went to open session, and the main point of contention was between the “static” and “dynamic” physics positions. The static position was similar to Stern’s; the emphasis would be on the intrinsic shape of the planet. “Dynamics” is a reference to the orbital properties.

There was one more draft, then the Plenary Session of the IAU met, and debated some more. And this is the result:

The IAU…resolves that planets and other bodies, except satellites, in the Solar System be defined into three distinct categories in the following way:

(1) A planet [1] is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.

(2) A “dwarf planet” is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape [2], (c) has not cleared the neighbourhood around its orbit, and (d) is not a satellite.

(3) All other objects [3], except satellites, orbiting the Sun shall be referred to collectively as “Small Solar System Bodies“.

Footnotes:

[1] The eight planets are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
[2] An IAU process will be established to assign borderline objects into either dwarf planet and other categories.

[3] These currently include most of the Solar System asteroids, most Trans-Neptunian Objects (TNOs), comets, and other small bodies.

And just to be clear, a “dwarf planet” was not, despite the name, a category of planet; they passed an additional resolution to make it clear.

[I have seen clips of the actual vote, hands raised in the auditorium. I can’t find one now, or I’d include it.]

So the planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

The dwarf planets (a subgroup of the Small Solar System Bodies), most likely includes: Ceres, Pluto, Quaoar, Sedna, Orcus, Haumea, “Xena”, Makemake…and one other, Gonggong. This is a fuzzy line and there are others already known that arguably belong on this list.

The Aftermath

And so that was it for Planet Pluto. To put the nail in it, within days Pluto was given a minor planet number just like any asteroid or Kuiper Belt object: 134340 Pluto. It’s now marked as a “Small Solar System Body.”

The reaction was intense. The public of course hated this and still does.

But it’s not just the public. Many planetary scientists (not just Alan Stern) also disagree.

This issue will be revisited some day. Personally I like Stern’s suggestion better than what we got. Or perhaps the best suggestion is to just drop the word “planet” entirely since it seems to have emotional ties. Should every round object that’s not a star be a “world”?

This is NOT the first time we’ve reassessed the concept of a planet, by the way. The other times that I know of are:

1. Any permanent wandering object in the sky was a planet; that included the Sun and the Moon, originally. Once it turned out the Moon orbited the Earth, and everything else orbited the Sun, that made the Sun “special” and the Moon a mere satellite of a planet, Earth.
2. With the discovery of moons around other planets (the Galilean moons of Jupiter in 1610, but also the satellites of Saturn and Uranus), we started seeing the term “Planetary Satellites” (which Stern re-used) used for them; that term continued to be in use well into the 1700s if not later. It’s now often used for the big seven moons (the Moon, Io, Europa, Ganymede, Callisto, Titan and Triton); the ones I’ve been calling “large moons.”
3. The asteroids were considered planets at first: Ceres, then we had Vesta, Juno and Pallas. They were all small and in the same general location, though so they quickly got reclassified as “minor planets” or even “asteroids.”

If you relish irony, after that flurry of discoveries in the mid 00s, only one more solid dwarf planet candidate has been discovered, and that in 2007: 225088 Gonggong, which varies from 33.8 to 101.2 AUs from the Sun, orbiting in 554 years, with a diameter of about 1230 km (give or take 50 km). It has one known moon.

…And Back to “Xena”

As for “Xena”, that same meeting settled its status, and the permanent name 136199 Eris was chosen. Eris’s moon was named Dysnomia. Eris is round. Dysnomia might be.

Eris was a Greek goddess, the personification of strife and discord. Dysnomia means “lawlessness” which (interestingly) might be a reference to Lucy Lawless, who played Xena.

What perfect names for the objects that triggered such a furor!

(Next time, we’ll look at the TNOs themselves, most especially Pluto [it’s by far the best known] in more detail.)