I looked up the figures a few days ago - but having since driven to the other end of the country, I've forgotten the precise details. IIRC it was something like Goofy having a higher aphelion - so most of the time (and length of orbital arc) it is going to be further out than Pluto (by a few %, but it also has higher eccentricity, so it's aphelion is lower than Pluto's (and indeed, Neptune's ; which is also true for Pluto). Since orbiting objects travel faster at aphelion than perihelion, that makes the average orbital period of Pluto and Goofy the same (or their year the same, or their semi-major axis the same ; these all mean the same thing) despite Goofy travelling further per orbit than Pluto, with a faster arc near perihelion.

You see the same sort of thing with, say, Uranus, Neptune, and 1P/Halley ; Halley and Uranus have quite similar orbital periods, but Halley's aphelion is well out beyond Neptune's orbit. the long period it spends out there is counterbalanced by the 3 year long Sun-dive it does form (approximately) Saturn's orbit, to the Sun, and back out to Saturn's orbit.50-odd% of it's orbital path followed in about 5% of it's orbital period.

Just because Newton's laws are quite simple, doesn't mean that their consequences are simple. Just ask (if you can get his bones to talk) one J. Kepler, who had to work out the orbits from raw observational data, unsullied by Newton's theoretical framework.

(It still sometimes astonishes me that there is no simple way to calculate the length of an arc of an ellipse or it's total perimeter - you have to do a really complicated, progressive approximation calculation for each specific shape of ellipse. Which, when you realise that Kepler would have had to make hundreds (thousands?) of such approximations while reducing Brahe's data, explains why Kepler came up with at least one relatively good approximation to the length of an ellipse's perimeter.)

hey combine hydrogen from with carbon dioxide,

Hydrogen from what or where?
If, like almost all *industrial* hydrogen, it comes from cracking natural gas, that's as something pure magenta (whatever the complimentary colour to green is).
(Our "analytical grade" hydrogen was probably sourced from electrolysis - certainly when we made it on site, it was ; but that was substantial cost of equipment and maintenance time. Our systems really cared about contaminants at the part-per-million level.)

A propos not a lot - my BOINC installation of "Asteroids@Home" has just started kicking through computations for the first time in ages. (BOINC is an indirect descendent of the SETI@Home project, generalised for a variety of distributable computation projects ; Asteroids@Home is a project that "uses power of volunteers' computers to solve the lightcurve inversion problem for many asteroids." Lightcurves are brightness versus time ; once you correct for distance asteroid to Sun and asteroid to Earth, the cross-section illuminated and rotation speed drop out - after considerable maths.

Probably someone has posted a new batch of data on something's light curve, and the rotation speed and/ or shape model is being re-analysed.

It's a small contribution.

I just find it absurd to demote Pluto to a non planet and then classify other climbs as Plutino, is pretty inconsistent.

IIRC, the term "plutino" was being used *before* the 2006 (?) IAU definition. Cart and horse sequence race condition.

But then again: you could call them Neptino, or something, or? And Pluto would be a Neptino,too.

There are bodies in a 3:2 resonance with Neptune. And other bodies in a 5:3 resonance (while 6:3 or 3:1 resonances are relatively empty : see "Kirkwood gaps" in the asteroid belt - same physics, different dominant body (Jupiter) and swarm of "test particles". And other bodies in 7:2 resonances. I can't remember the name of such a body (and can't be bothered to research it) so in keeping with other cartoon dogs, let's consider this to have a largest member "Scooby" and call these "scoobinos" (it's a class, not a proper noun, so no capitalisation).

By your naming convention, these too would be called "neptinos" (no capital), with no distinction from the 3:2 "peptinos" generally known as "plutinos". By the naming convention I describe, and which is actually being used, "plutinos" are a distinct (if related) class to "scoobinos".

It's a nomenclature - it's intended to describe meaningful (to a certain class of people, KBO astronmers, for example) differences in a compact, memorable manner.

The previous posts were about periods. You seemed to shift to considering orbital velocities (or speeds ; it's not precisely clear), which is a different thing.

Yes, the tie to the period of Neptune's orbit should also constrain the period of the Plutinos over a suitable averaging period. But when you get to things like "tadpole" and "horseshoe" orbits, that can have significant variations of order-of a percent in period, resulting in the longitude of perihelion (direction of perihelion of the orbit, measured from the Sun) of the Plutino oscillating around the longitude of aphelion (parallel meaning) of Neptune's orbit, and tracing out a "horseshoe" shape (when projected in a co-moving frame with Neptune's orbit) or a tadpole shape. Which means variations in the orbital speed of up to a percent or so and the Plutino moving ahead in it's orbit compared to Neptune, then falling behind. Over some hundreds of orbits (10s of thousands of terrestrial years) the orbital speeds will average out, but there are enough wrinkles to be interesting.

I learned about these wrinkles in orbital mechanics in the mid-90s, when I got a phone line and dial-up internet access, and heard about an object called Cruithne (good grief - it's a 4-digit UID ; I feel old). Just because the physics are simple, doesn't mean the results are simple.

it should take longer than Pluto to complete an orbit but instead it takes a year or two less.

That would be about a 0.5% variation. The perihelion of (I've forgotten the object's name ; doesn't matter ; let's call it "Goofy" because it's not Pluto) the orbit will be reached sooner than Pluto's perihelion, which also means that Neptune's aphelion (they're in a 3:2 relationship, remember) is relatively close to Goofy. Which means there will be a decelerating force on Goofy's orbit (Neptune is the dog, not the tail. Billions of fold difference in in momentum.) reducing it's orbital speed in comparison to Pluto's orbital speed. Which will mean that Goofy starts to fall back in it's orbit compared to Pluto. Yes, that's cyclic. And no, there probably aren't enough counteracting torques for other objects to damp down the motion. (In the Earth - (3753)Cruithne system, all involved bodies experience torques form Venus, Mars and Jupiter of roughly similar magnitudes, which will damp the motion eventually. Or result in an orbital interaction which will put (3753)Cruithne into an Earth-crossing, Venus-crossing, or Mars-crossing orbit, when bad things become much more likely.

Yeah, it gives me a headache too. You remind me, I was trying to help a guy who runs an orbital simulator code set to write a manual for it. It is very headache-inducing. And I don't understand it well either.

What is Tony's tool called ? Orbit Simulator (though the internal scars on the software say it was "Gravity Simulator" in an earlier life.) - which s interesting to play with. But the help files aren't great. It's a complex tool for simulating a complex system.

Did you miss the phrase "reproductively isolated"? I specifically typed and spell-checked those letters so that you could ignore them and their import. I'm glad to see that you did, indeed, ignore a vitally important part of the point I was making.

Your citation that there are several other strains to be found in our genomes also means by definition that these strains were not reproductively isolated from our (strain, species, lumpy splits or splitty lumps?) of apes.

My training was in considering "species" as a morphological concept ("genetics was for the Zoology department on a different campus, not for Geology students), but even then, in the mid-80s, we were well aware that we could be splitting (for example) a sexually dimorphic species into two, and also had to pay attention to "provincialism" (morphological variations between members of the same species in different regions) as a possibility when considering whether to "lump" two specimens into one species, or split them into two. An introductory lab exercise was "Here are boxes each containing a couple of hundred fossils per group of 4 - divide yourselves appropriately - all from the same bed in the same quarry. (Mid-Jurassic, for what it's worth.) Without consulting your text books, and without discussing between groups, assess the number of species in each collection." Which is applying the morphological species concept in a laboratory setting.

At that time, we had no anticipation that archaeology (verging on the closest shores of palaeontology) would ever get access to genetic information. That is why it literally wasn't on the curriculum. Though my home area was watching the application of "DNA fingerprinting" to a couple of local rape cases - you may have heard of the developments in this since. This "genetics" thing was of some importance, if of no relevance to palaeontology.

3 Species are considered proven, Homo Sapiens, Home Neanderthalis and Denisovans.

That very question is the point - are they 3 species, or one species with regional variation? Yes, I did see the claim that the skull assigned to Homo longi, and I said at the time that "that is going to be a beautiful argument point between the morphological species concept and the genetic species concept. That is going to be in textbooks for generations." As, indeed, you are proving.

Where, in the published formal literature, do you see an assertion that "this genome and this (these) body fossil(s) are the holotype(s) for a species which we are erecting called Homo denisova spec.nov. ..." Because that is what "declaring a new species requires" - a holotype, a description (emphasising differentiation from pre-existing similar species) and a unique species name. (Assignment to a genus is common, but not required ; assignment to a new genus is rarer, but still common ; all higher taxonomic levels are matters of debate and opinion, and get revised on a regular basis. Which is why you generally cite whose definition (of what date ; people change their opinions with new evidence) you are using for any particular higher-level taxonomy.) [People sometimes re-use species names, but try to keep them unique within a taxonomic branch. But it's not good practice. And with search engines, it is pointless these-decades. there is no shortage of words available, even if your linguistics are lacking.]

When the Denisova genome was detected and announced, the authors (Paabo and associates, IIRC) explicitly stated that they were not asserting a new species. Which is why, if the association between the Homo Longhi body fossil and the genomes from Denisova (and several other sites, plus modern SE Asian populations) is accepted, then it is the Homo Longhi name that the genome will be attached to. The genomic data was uploaded to Genebank, MolbioBank, or something similar. I'm not sure that genetics has got to the point of having rulebooks as comprehensive as the ICZN and the botanists. Since it's pushing a century that the ICZN have had a rulebook, maybe now would be a suitable time for the geneticists to get their databases and practices into some sort of rulebook. IANAgeneticist ; they might have done so already.

Has someone been putting something in the water? That's the second 4-digit UID I've seen in the last few days - and I've barely touched the Slash for months.

'non planet' is called a 'Plutoist'?

To quote the paper's Abstract (becasue I haven't got to reading the body yet ; nobody has raised a point that has needed me to read that far, yet :

A stellar occultation by the ~ 250-km-radius plutino (612533) 2002 XV93 on

And :

Our findings indicate that a fraction of distant icy minor planets can exhibit atmospheres possibly caused by ongoing cryovolcanic activity or a recent impact event of a small icy object.

This is a "small icy object" (they don't even waste consideration on it being a "dwarf planet" or not ; it's probably not particularly spherical, but with only 2 chords and a non-chord, it's hard to say what the actual profile is) which has a "plutino" class of orbit (meaning : 3:2 orbital resonance with Neptune).

Oh, it's you, Angel ; I don't remember you being a particularly "Pluto is Planet IX" obsessive. Or are you just prodding the hornet's nest to elicit amusing buzzing sounds ?

Since both tails (orbit of Pluto ; orbit of (612533) 2002 XV93) are wagged by the dog of Neptune's orbit, and are constrained (and adjusted) by orbital resonance to stay very close to 3/2 of Neptune's orbital period, then both of their average orbital speeds will be similarly constrained by Neptune's orbital speed.

There will be a variation between the perihelion speed and aphelion speed, but that will average out over the orbit. Check Kepler's Laws.