Titania foam

West Virginia University are talking about 3D-printing in microgravity. The base-product is titanium-dioxide foam, which they call titania.

This foam blocks ultraviolet at 0.2 millimeters, about the width of a thin coat of paint. That makes it useful for shields around structures as are also in microgravity, namely the stations we currently got in LEO. It might also be photocatalytic.

And it might be cheap, in LEO. Much of our space junk is titanium. Maybe we could just sweep up some rubbish and use that to make the foam.

The researchers used a Vomit Comet in freefall so only had 20 seconds at a time to print this stuff. The next step would be to try this longer-term in LEO proper. If we're ever allowed to do this.

Starlift

ToughSF links Jakub Grygier on the stellar lifting concept. Get something into a low orbit around the Sun as to extract its hydrogen and helium.

For helium, starlifting involves lasers and/or magnets to speed up stellar fusion at local points on the Sun's surface - basically inducing flares. The helium would be condensed. Into liquid helium. Which is a superfluid. Er.

I think gathering hydrogen into hydrates or even soot would be better. They stay bound with their molecules at high temperatures. Anyway the cost of hydrogen storage and transport seems like it's getting lower.

Where do we transport this stuff...? I'm thinking any of our hydrogen-poor planets, asteroids, and of course our own Moon. Probably not Venus; the acid has sufficient hydrogen at cloud-level, and statites can gather hydrogen in orbit.

Overall I rate this whole scheme as "silly".

The Core: Martian edition

Last week NASA InSight put more constraints on Mars' innards. The core is molten, which we knew; blanketing it, is a sheath of melted silicate. Glass, I guess.

Anyway ToughSF calculated how to restart this dynamo: 2e28 joules. 195 billion B41 fusion bombs, down the mohole. Um.

Better ideas come from the comments: lensing, for about an hour and a half; or pushing asteroids into an elliptic orbit. That latter might start with Phobos which is, you know, already there, and we gotta get rid of it anyway. CybertechDan is more thinking a hundred km diameter Luna-like; Phobos is only eleven. So just move a S-type rock that's in the 90s km diameter down to intersect Mars and crash Phobos... bro.

Apparently this is a slow day for news.

The Lecker / Mirza synopsis

Last week I got around to (re?)reading Michael Lecker. Looking around this mine own blog I found a link to Sarah Mirza. I posted what I had, yesterday morning; then spent yesterday afternoon - which was cold - looking for interconnexions.

Lecker is a star in the field of early Islamic documentation. Mirza is well-aware of Lecker's excellence in output. Somehow, Mirza writing no earlier than 2011 lacked access to this particular 2005 Lecker opus. Their papers are therefore independent. They do however overlap in sources... making this a synoptic problem.

The Lecker and Mirza base-text is what Ibn Sa'd claims as quoted literature in the latter's Tabaqat. Their main focus is a single chapter (or two) in the first volume, second part. Oddly these authors did not share editions of that work. I use Moinul Haq's 1967 translation, based upon a century-old Arabic edition. This Arabic is what Mirza used; perhaps better-used, inasmuch as Moinul Haq sometimes transcribed gibberish, like "Jurmuz" where is obviously "Hurmuz". Lecker had used something else - I think a more recent edition, which edition Lecker finds wanting and occasionally seeks to correct.

Lecker went through what would be pp. 15-86 in Moinul Haq's basis, pp. 304-421 in translation. Lecker goes this far because the "deputations" which follow p. 38 tr. 345 also hold some (putative) correspondence. In what correspondence he found of interest herein, he related them with other collections of ahadith especially Waqidi's Maghazi. Lecker argues that Waqidi also had a Tabaqat, which he let Ibn Sa'd copy (and transmit); and that Ibn Sa'd used this as a basis for his own work, much of what we see in pp. 15-86. Usually Waqidi can be sniffed out by the "they say (qâlû)" formula, Waqidi being famously loose with his chains of asanid. Lecker (p. 5) notes that Ibn Sa'd is meticulous. Lecker admires Ibn Sa'd too much to add, "by contrast".

Mirza - by contrast with Lecker - touches only pp. 15-38 tr. 304-45. Mirza by bypassing the "deputations" also bypasses their correspondence. She moves off to other Islamic sources.

Lecker misstepped in p. 3 when he says of Majmuat al-wathaiq, 301, #198, 199: the texts of two letters given by the Prophet to two members of the Tayy were not preserved. Letter #199 is to the Jabalayni. This one is certainly "I, 280" that is p. 30 tr. 331-2.

Mirza p. 110 looking at Ibn Sa'd p. 28 tr. 327-8 relays that report upon the treaty with Maqnâ, which - correctly - she sees as not from Waqidi as was so much else. But she says that this little chondrule came from al-Sha'bi. I do not find this attribution in Ibn Sa'd (which, remember, is the edition I use, albeit in translation); she maybe has it from Baladhuri. Also - in hindsight - Mirza should have trusted Milka Levy-Rubin (2011) a little less; this needs Luke Yarbrough's corrective.

Through their independent lines of inquiry, Lecker and Mirza agree that the correspondence (Lecker) and treaty (Mirza) inclusions in Ibn Sa'd, mostly from Waqidi, are much earlier than Waqidi. Lecker finds that separate chains often link to some source in the earliest Marwânî era. Mirza, for Sha'bi(?) on Maqnâ (despite her error), does about the same. Mirza's main argument concerns the language of treaty, which uses dhimmat Allâhi where an "orthodox" Muslim would not.

Mirza's most shocking finding (to some) is that the early treaties allow haram sanctuaries to other tribes as have signed a pact with the Believers. This suggests that Mecca might have existed! ... but also suggests that Mecca wasn't universal, until the Zubayrids made it universal.

Rhenium demand just exploded

Columbia University's quantum initiative has introduced Re₆Se₈Cl₂. This is a silicon-free semiconductor; useful for circuits and - although the research doesn't say this - solar panels.

Here we get to learn about the existence of "superatoms", and dig further into the wonderful world of quasi-particles. Any lattice over absolute zero vibrates. The vibration emits "quantum particles", phonons. Then they affect electrons, and the lack-of-electron (the quasi-p) here called an exciton. When an exciton and an acoustic-phonon love each other very much, thus ensues a new quasi-p: acoustic exciton-polaron. These flow without scatter.

Excitons - which are just electrons moving off the gaps - are fast in silicon, slow in Re₆Se₈Cl₂. That slowness turns out to be good, here; its excitons "pace themselves". Acoustic phonons haven't gotten any faster, so the excitons meet them more efficiently. The electrons move twice as fast overall than in silicon, and lose less heat.

In theory processing speeds in theoretical devices have the potential to reach femtoseconds—six orders of magnitude faster than the nanoseconds achievable in current Gigahertz electronics. That is still brute-force processing, not quantum computing; but not all calculations need be quantum. Also Columbia haven't got there... yet.

Columbia only found this as a byproduct, of a high-res motion-capture microscope they're working on. This microscope will make that university a hot place for similar semiconductor research.

Which research, the team admit, they might need. There's good reason this super duper atom won't be wasted on solar: the "Re" stands for rhenium. We don't own a lot of rhenium on Earth.

But for the moment, this product seems like a spectacular macguffinite for getting up to 2-4 AU, to nose about iron-rich asteroids.

The Muhammadan correspondence

I don't know if I'd ever skimmed through Michael Lecker's 2005 book People, Tribes and Society in Arabia Around the Time of Muhammad. Lecker has, at least, provided "The preservation of Muḥammad's letters" for free on academia.edu. So; in the event I hadn't read it the first time - let's read it now!

Lecker goes through Ibn Sa'd, readily available in that 1967-72 translation, for the letters which the Prophet supposedly composed and sent out to others. In Islamic dogma (as it reads the Quran), Muhammad couldn't read. First up he was a trader so - meh to that. Also evidence of the literate Prophet goes against Sunnite interest. The correspondence further intersects (thematically) with the treaty genre, often considered early - note "the Constitution of Madina". So I shall approach Lecker with an open mind.

Lecker is pondering what Ibn Sa'd might have used for sources, in case he was making it all up. Lecker figures that indeed Ibn Sa'd was not making it all up. His sources include my boi al-Walid bin Muslim; also al-Mada'ini (hamza required for this 'Iraqi), and - sigh - al-Waqidi. Waqidi is the sort of someone who'd make it all up. On the other hand this blog - and the Muslims - hold much regard for Walid, and for Mada'ini. Back to the earlier hand, the Muslims do admit that Walid (for one) didn't always call from the best sources.

Walid's creduility wasn't a problem for me as I was observing an aurora with him; but where he has some uncle of a Malik bin Ahmar al-Judhami descendent read an old leather scrap to him... yeah, I dunno.

All Ibn Sa'd's sources which Lecker finds had gathered the letters from various Islamic noble lineages. Lecker notes that the written word was not trusted in the earlier Islamic generations. Such legal specialists as Ibn Malik, at least, would rarely use the correspondence. They'd rarely use the people who claimed them, neither; Lecker found difficult to track the earlier asanid in the classical biographies (mainly Lecker used Mizzi). The temptation toward self-serving forgery would appear to justify the lawyers' skepticism, especially where in Muhammad's own name. The biographers (notably Ibn Ishaq) could use "riqaiq" as it was called but only on pain of men like Imam Malik deriding them as liars.

Venerian tectonics

I caught this yesterday afternoon: Venus once had tectonics. Brown University didn't gather that from the uplands of Venus today, if you can call them continents; those are all push-plateaux like Tibet (Maxwell in particular looking like a himalaya). The present state of Venus looks like it was perma-broken by an impact. Brown got their result, rather, from abundance of the gasses in Venus' atmosphere today, namely nitrogen and carbon-dioxide. These developed from starting-points in Venus' distant past.

I don't know if the Brownies used pre-oxygenated Earth as a proxy. Back in 2020, Lehmer and three others got "Atmospheric CO₂ levels from 2.7 billion years ago inferred from micrometeorite oxidation" - those meteorites being dug out from here. 2.7 Gya, our sun was "20% fainter". They mean: at 1.8 Gy after the end of T Tauri, Sol's luminosity was 0.808, from a 2001 paper's Table 2. CO₂ then was over 70% by volume. Although some claim that green "oxygen oases" existed already.

For Earth, though; that earlier team didn't constrain pressure. Did the Brownies constrain pressure on contemporary Venus? I mean, not quite contemporary; they're more going for 4.5-3.5 Gya when luminosity was ranging 72-7%. Venus then would have incurred some 1900s W/m² which is still quite a bit more baked than Earth's 1361 today. If Venereal atmo was CO₂ (with H₂O vapour?), as later Earth suggests, Venus must have been a greenhouse back then too. If the surface was watery that atmosphere must have been thin. If CO₂, then that layer was not liquid.

I am, however, interested to know if supercritical CO₂ can conduct tectonics as water can.

Solar power and its discontents

The worry among some of the SCIENCE!skeptics, which includes me, is that solarfarming, although perhaps now viable, scales poorly for a modern society's energy needs.

I am not adverse to megaprojects, G-d knows, but solar is a space-hog compared with (say) a modestly-sized plutonium reactor. Same goes to wind, honestly, and we're already hearing resistance from the Sami about that. Back to solar, Morocco is embarking upon such a megaproject, basically carpeting the Sahara (which they claim will also green it). How are they reconciling all that with the Tuareg?

So: two articles as might save solar - defined as, bring it into competition with fission (and with just plain coal), if only for land-use concerns. Especially where we don't actually have nuclear fuel, and/or don't want to ship it: you guessed it, nearearth asteroids and Venus. Maybe even Mars.

One is to increase the incoming energy. No, not by boosting the Sun; the Sun can do that by itself. I mean concentrating rays in space and then beaming down the coherence - to Morocco, or to Death Valley or wherever. Also it seems other materials are more efficient than silicon, presumably much more so than the mercury method which George O Smith wanted.

Gaussian splatting

I don't know splat about Gaussian splatting, so like any good blogger I figured I'd poast on it anyway. May as well start with Aras Pranckevičius' latest.

Rather: I gotta start before all that. I keep hearing terms like "NeRF" and "raster". Best I can tell it goes like this - first, the splats are created; then, they are rendered. These tasks should - I think - be done on different machines, with different video cards.

The "Ne" means neural; "RF" is Radiance Field. RF is how the designer takes an image, rather several images at several angles, and then the software figures out how to approximate them. These go into the data-files you download from Steam.

"Raster" is basically the pixels being displayed on your screen, like the "1024" memory-address and beyond in the old TRS-80. Like - say your data describes a vector, a line going from one two-dimensional spot [x,y] (0,0 being the top left maybe at the 1024 address) to the other [x2,y2]. Bresenham had the 1962 algorithm for that: to alias the line - here, as a pixel-staircase.

Who cares, right. Disney cartoons are alias; any motion-picture is alias, as a 2-D representation of a 3-D series of scenes. But there's alias and there's alias; shifting pixel-ladders for moving lines (say) can get annoying. Hence the "anti-aliasing", to fuzz them over. Classic games often make this optional, as this process takes up computer resources beyond what was to be rendered already.

3-D objects tend to get raster'd as polygons, which means lots of those lines - three per triangle.

With Gaussians, we forget a lot of this. Radiance-field creation isn't "neural"; it's its own thing. And when it is rendered, or "raster'd" or whatever - it is rendered as a blob. No more GPU line-drawing; it's done in CUDA. We may expect lots of aliasing, since the Gaussians are at the mercy of the developer's 3-D pictures; but that anti-aliasing would render... differently, than the old triangle-fuzzing. Better or worse, will depend upon different factors.

When I first heard about this, we had Gaussians in 3-D but they were static, the fourth dimension supplied by some enduser rotating his camera around the object. Last week, I heard from moving pictures being done into Gaussians. As reciprocal-squareroots have taught us, objects in motion can cut corners on anti-aliasing, and on storage generally; which is good, because Gaussians are (presently) memory hogs.

I foresee a major fork in GPU programming, at least in the drivers, maybe even in the hardware. One side must optimise for non-Neural RF by the designer. Consumers then handle the Gaussian non-vectors. In the near future that consumer seems to be a movie-director, planting a 3-D Gaussian phantasm into the frame with real objects. But later there may be games.

Luna BACKDATE

Some data from our own Moon is rolling in. A zircon from Apollo 17 is reading a 4.46 Gy age. This restores earlier estimates, back from the 4.425 Gya which Vox Day told me about. I mean, unless the zircon hails from old-Earth or Theia which no-one seems to accept.

In future we might not need the moon proper for our sample-return needs. The 100m-ish achondrite (not "tektite", boomers) (469219) 2016 HO₃ was already known to be lunar, not a S-type. It lately turns out this one got coughed off the Lunar surface some millions of years ago and will stay in its Earthlike orbit for millions more, long after the squatters demanding we call it "Kamoʻoalewa" become a footnote. UPDATE 4/26/24: Bruno?

I don't find a settlement of colonists upon this dried-out moonchunk, worth the bother. Also I don't think we've a handle on whence, on the Moon, it came. I think, though, that it would make for a fine locus for its own zircons; also, maybe we should get that handle on its origin. And 'tis always cheaper to dock with a floater, than to land and take off onto/from 1.625 m/s².

Before the tabernacle

Lisbeth Fried has thoughts on the P/J strata in Genesis. She notes that J assumes a sacrificial faith, going back to Cain and Abel; where P assumes a Near Eastern sacrificial religion (sometimes called "cult") which demands a Temple.

What about before the Temple exists? J says - any man whom God blesses can do sacrifice, at any place, as long as the man sets up an altar. P says - Tabernacle, around the Ark. J would ask - what about before the Ark; to which P basically shrugs.

Fried figures that J relies upon... the Javanim. The Greeks left some record of sacrifice without a Temple. Sure; Fried knows that the Greeks often built their own temples. (And they did it early: Mycenaean shrines are noted in Pylos' Linear B, Room 18 at Mycenae proper is usually considered such a shrine, and so on.) But for the Greeks, shrines were like telephone-booths; the god might attend upon the shrine, but his home was elsewhere - like Mount Olympus. As far as Fried knows, the Greeks are the only people who did this in antiquity (excepting animists whose dieties were nonuniversal river-spirits); so Fried assumes that's that.

To me, sacrifice without Temple looks basal Indo-European. Therefore I wouldn't, to explain J, demand Hellenic influence.

Maybe certain Hurrian "Horites" were known to set up altars without a temple, on campaign, which practice was noted in Israel. Or the Cimmerians, or the true Ashkenaz - "Scythians", to Greeks. Any trader from the Near East who'd traveled far enough would observe "primitive tribes" doing that, and extrapolate therefrom that the Semites too might have behaved like this in their deep past.

Father of greatness

We had some Second Isaiah at Mass this morn. I see that TheTorah.com is on a similar case: Cyrus grandson of Cyrus of Anshan, setting up the province Ebernari.

I dealt with this awhile ago, on Abraham bending down to kiss the rod of Bera, as it were. The common enemy to Canaan was the lord of Abraham's old home beyond the Aramaean Euphrates: the lord of Elam.

TheTorah is focusing on Abraham's other name - Abram. Both names may be folk-etymologies of the same name "Abraham". 'BRHM is, it seems, not Hebrew. Everyone figured that 'B was your Semitic ab, "father"; but what's RHM?

In one tradition, it used to be ram. This may have to do with the man's origins in the Mesopotamia, whence the greatest Semitic-speaking empires (Egypt wasn't Semitic, didn't count). Isaiah had somewhat-consistently deemed the Assyrians, especially, as ram - against Judah's god, who would oversee the fall of Ashur. In the other tradition RHM is (somehow) related to hamon, a multitude. A third wordplay involves [2] Isaiah 51:2, וְאַרְבֵּהוּ, which seems innocent of both. It all looks like Ezekiel 33:25f, a direct reaction to the present inhabitants of the Land who scoff, at Abraham's children: וַאֲנַחְנוּ רַבִּים. (Ezekiel was at heart a Babylonian.)

Mark Brett has an idea: Abram was the father of a great nation. First, YHWH grants Shechem(!) to Abram. Then, YHWH assigned Abram to reign from river to river (much noted by Unzpoasters). The Persian satrap happened to own that territory. Abram looks, to me, like YHWH's khšaçapâvâ: some founder of the Samaritian nationstate. It is this people who say וַאֲנַחְנוּ רַבִּים.

Abraham on the other hand - Ezekiel's ancestor - rules only his own people. His portion is to be a patriarch but biding his time until his progeny can expand. For Genesis his rights come out of resistance to Elam-dominated Mesopotamia, which resistance was clustered around the Salt Sea plain. I can't help but suspect that the arm of "Elam", there and then, was locally-based somewhere closer. Maybe... Shechem.

Both accounts are set in early Genesis, back when Tall Hammam was still standing, which everyone knew was before the Pharaohs (accurately, it turns out).

Utah as the royal preserve

Congratulations, I guess, are in order to the Bennu team for extracting that canister from Utah. Unfortunately our masters reserve the privilege of landing samples at Utah only for minions. Private companies, like Varda, don't get to land there.

If you're not getting your antiretrovirals, LOL and die f@gz - says the FAA.

The Senate is on the case of FAA overreach but, unfortunately, if there's a company the Democrat-staffed FAA despises more than Varda, it's SpaceX.

Scaling a Jovian colony

ToughSF links Jay Eaton's worldbuilding, this "world" being whatever Jupiter anchors. Eaton doesn't mention the E/G Laplacian but he's welcome to it.

I find interesting that most people here will be on a station; this "Nexus Jovia" is in the JCL5 halo. It fits, er, 89 million people. Jensen thought he could squeeze almost 70 million into Šteins' 6ish km / 1.98e14 kg if reassembled into a torus, (4042,1915,638). "Realistically" he figured 5.79 million. (And he'd start at Atíra anyway, like me.) Jupiter has lots of asteroid-captures bigger than Šteins, like Themisto (9 km); Jovians wouldn't even need to construct this thing from Callisto.

I do agree with Eaton that the (vast) majority prefer to inhabit a station permanently, where gravity is what you make it; than to inhabit Callisto or beneath Ganymede permanently, where you're stuck at, what, about a tenth Earth's. Low-gravity is bad for you mmkay.

Anyway, even if Eaton's population-numbers are absurd, because science-fiction, he's only absurd by a single magnitude-order: Jensen is still talking millions. And there's all the water anyone could want, out here; ammonia too, I reckon.

Next problem: power. Jovians get only 50.26 W/m² from the Sun; the Lunar antarctic 80s° might count on 1361. Maybe Ganymede can handle things with a superconductor. If the colonists are in the millions then Callisto, and JCL5, gotta import power. So does my interlunar Laplacian.

Eaton reckons that Amalthea can anchor some magnetic tethers, and beam the microwaves outbound. Personally I was pondering dismantling Amalthea as to shield Io with its rubble. But maybe Amalthea can spare the mass, and keep enough leftover for the beaming. Maybe Io can plunder Thebe first and spare Amalthea.

BACKDATE 10/22

Airlocks

Whilst pondering all that nitrogen we don't got, I have to consider when I'm ejecting gas right into space. Like: from a shuttle-launch. Most commonly from an airlock. Which LEO can afford because just toss nitrogen and oxygen up there with SpinLaunch (bro). A silicate-type rock at (say) L5 averaging a full AU from Earth, might not afford it.

My station might allow for some mitigation. The various stations and capsules we've launched into LEO are thin aluminum (mostly American) cans. My station has thirty meters of carbonaceous rock between breathability and - not. Fifteen if silicate. Apart from sheer volume, I also believe I can use carbon-dioxide where I need air-pressure differentials and don't need humans.

So far I've come up with the syringe. Say: 1.78 meter radius for 10 m² floorspace, so 150-300 m³ volume. The chamber is filled with carbon-dioxide.

The button which calls the elevator (assuming American) pulls the cabin down from the surface. If the cabin is full of CO₂ who cares, this just vents into the ambient station. The lads step into the airlock and its 2.5m ceiling: 25 m³, minus total volume of said lads. Airlock closes. The people suit up.

Cabin first equalises with the CO₂ of the chamber. Cabin then rises. Cabin vents into space - but mostly it's just the CO₂ venting out. Crew does the EVA, returns. CO₂ is vented back into the chamber: in fact, it can be pure CO₂ from dry-ice. Back down they go, venting that back into the station.

25 m³ 2/3 nitrogen at 0.6 bar = 60 kPa is lost per EVA. I still don't love it.

But this can be made less lossy if the cabin atmosphere is pumped with CO₂ both-ways.

BACKDATE 10/22

The high-density meteorites near us

I am still avoiding direct Psychepoasting but I did catch, on Jimmy Wales' misinformation emporium, reference to enstatite chondrites, bencubbinites, and mesosiderites. I might be safe if I just look into those.

They have in common that they are denser than stone. But there's a reason they're not classified as the same thing. I don't see how these three could come from the same place.

Bencubbinites form a metallic "CB" group of carbonaceous chondrites; they are associated most with Pallas, possible home of the "CR" group. (Don't confuse them with "Pallasites" plz.) Enstatite chondrites by contrast formed where there wasn't much oxygen - and they're rare. The Enstatites may well have formed with the Vulcanoids (which we can't see in the Solar glare).

Luckily for near-earth asteroid colonists, I don't think Atíra and similar be enstatites. They haven't lost all their oxygen yet. Nitrogen and hydrogen, sure - still a problem. Colonists who want an enstatite rock (because GOLD) will need to get further-in than Venus, with all the delta-V pain that entails.

BACKDATE 10/21: yeah - behind the curve again, here. Busy work week, not much news I cared to report.

Hall thruster is now being tested

This blog has noted the Hall Thruster. This seems to have started production in 2015. On its current voyage to the Beyond it uses xenon, ionised.

"Out there", in this inaugural mission, would be the El Dorado planetoid: 16 Psyche. The Falcon Heavy worked excepting NASA's greedy mission design, forcing to scrap the main booster (for which we taxpayers paid, sigh). I'm not Psychepoasting on account I don't know much about the shiny rock, which ignorance is widely shared hence the mission.

Anyway this Hall is slated to take 3.5 years. Exhaust velocity is 80,000 mph (sigh) so ~35.75 m/s I hear.

There's an erosion effect, inherent in all ionic drives. Thus why it's important to run these things as hot as possible so that the actual cargo gets there before the engine conks out.

The mission was supposed to launch last year. It may be that this engine is already outdated. For a start, xenon is rare. I would see it replaced.

BACKDATE 10/18

Heavy metal 2023

Remember the Kessler space-junk syndrome in low-earth orbit, which Gravity made famous? Suppose we cured it. Purdue University are warning that we might not want to cure it all at once.

Purdue done run some maths that satellites as just burn up in the atmosphere (bro) do not annihilate. Burnination is a chemical reaction, like what was said about mercury, or the carbon from kerosene. Same holds true for the spacecraft itself. Titanium, aluminium, stainless-steel... none of which you want in your tuna fish sandwich.

On the one hand this is mainly a political problem. It is unwelcome for Elon Musk especially. NASA can launch its inefficient rockets because, being inefficient, the SLS won't go up much. Other countries can do whatever they want (especially should the US lose its next world war). This is the most problemative for the most productive. Perfect for government work.

On the other hand, at least reusable boosters are exempt. The point of that stainless steel monster is that it doesn't burn up; Elon gets it back or, should NASA order him otherwise, it falls mostly-whole onto a dolphin somewhere around northern Cuba, then sinks and becomes an artificial reef there.

So, maybe the plan should be to put less stuff in LEO and more in-between Van Allens. Which Starship should be able to do.

BACKDATE 10/18. UPDATE 1/19/24: Suppose the rocket were made of fuel? It doesn't launch from Earth but it doesn't have to.

Burning coal for nitrogen (and sulfuric acid)

Suppose I caught a mole of dry soot. The formula which Bergin's crew sent us was C₁₀₀H_75–79O_11–17N_3–4S_1–3. Molar weight of its components: 1201+76+240+56+64 = 1.637 kg. If I burn that in oxygen (or in ozone, oxozone; whatever - pretend I have an infinitude to burn): I get 1201+3200 carbon-dioxide, 76+608 water, and 64+64 sulfur-dioxide (again, not caring about the oxygen). I'd get the same 56g nitrogen in, I hope, gas form.

I concede Concerns with carbon-monoxide, hydrogen-sulfide, hydrogen-cyanide but these should (mainly) be containable until the oxygen does its work. Too much oxygen and we get nitrous oxides, or water-peroxide - but most of all, I have a Feeling about sulfurous even sulfuric acid. In fairness, I can count on that 76:2 hydrogen:sulphur ratio. Two H₂SO₃ (or H₂SO₄) molecules will sequester all the sulfur and leave 72 hydrogens free to make 36 water molecules (72+576). A 1:18 acid:water solution is, I understand, diluted enough to work with. Some of the carbon-compounds will get dissolved into this too. At 295 K I hear 0.07 mol% CO₂ just for water (pdf): so from the heated coal I estimate 0.2 molecules in solution leaving the other 100(-) loose as, mostly, free CO₂ gas. Back to the fluid, don't splash it in your eyes.

So, should my stone space colony want 46.3 tonnes of nitrogen they'll need to burn 1637 × 46.3/56 tonnes of space-coal; a 1353 tonne sootball. Which is a sight better than a million tonnes. Hopefully they can find something like this within the rubble.

And the sulfuric acid looks like a nice little bonus. The pure water alone would make 648 × 46.3/56 = 535.75 tonnes which should offer a bit more in cubic meters. 50×5×2 m³ looks like a swimming pool.

Air ain't free

H-types run at 48 ppm nitrogen (nuclei) by mass. Let us be more pessimistic; let us send our luckless COLONISERS to a shattered Hebe at an Atíra orbit, for 46.3 ppm. The mission: fill 100m×100m×10m with 46.3 tonnes of nitrogen gas.

I figure a million tonnes of the rubble to get 46.3 tonnes of the gas. And no cheating by using focused solar rays to do it: we must release the nitrogen under 15 meters of roof, sealed on the inside, so's to keep the gas from exploding into space. (Add oxygen to push the mix to 74.41 tonnes and keep the ceiling from falling, at that.)

That nitrogen will start in the form of N₂; but a colony will next want ammonium-nitrate, nitric acid, nitrous oxide and other compounds for food and profit. Hebe will, in short, make you work for it.

For Hebe proper, longterm, 6.1×10¹¹ tonnes of N₂ seem/s plenty. The question remains how Hebe's colony can get started. (Bennu's nitrogen is, I hear, good-to-go almost at the beginning; but this blog goes hard-mode.)

The nitrogen we need

When I was digging Bennu I aimed to deliver oxygen like sealevel Earth. That's by number - so by moles. I aimed 1/3 oxygen and 2/3 inerts at 0.6 bar. In practice we don't get gas of any sort in a near-earth rock. Noble gasses are for Mars and Venus - only. We are stuck with nitrogen which we liberate from the rock, if we can.

So. Can we do density?

A mole of nitrogen gas (no isotopes) is 28 grams; oxygen gas 32g. By weight 1/3 × 32g + 2/3 × 28g = 10.66 + 18.66 = 30g per mole of the mix. A little more if we were counting isotopes.

Avogadro's 1/mol is 6.02214076×10²³ but I don't care. I care now about ideal gas V = RT/P, = R 295K / 60000 Pa = 0.00492R [rounding up] = 0.04032 m³/mol.

Mole-by-mole that's a mix density 0.7441 kg/m³. Which seems low except - gas, not water (998.21 kg/m³); compare air on Earth 1.225.

On my asteroid oxygen is effectively infinite. So, 2/3 of those breathable moles are nitrogen. Note that I already did that - it came to 18.66g out of the 30g. This is 0.463 kg/m³.

On the top floor I want 30-foot ceilings and lots of space. The cubic dekameter is 10×10×10 so, 463 kg nitrogen / cube. On a modest parabolic trough I believe we can fill a 100m×100m×10m space for 46.3 "Mg" that is, tonnes of N₂ (plus O₂).

BACKDATED AGAIN 10/14

A diamond-dusted heaven

It was taking too long to continue ASASSN-21qj so, let us consider ASASSN-21qj-a for today. This planet has formed - is now forming - from a merger of two Neptunes over a sun-like, post-Tauri star. Its location isn't well-constrained yet but is, by Kepler, about the region from Ceres out to Saturn: normally cold. This has all happened rather late in a solar-system's evolution so, not much protomaterial left to scoop up. In particular we don't have much ice out here anymore...

That big hot radiant blur, I expect to end up with too much carbon trapped beneath its silica. Its carbon will mix with iron. There might even be fusion-processes, and critical-mass for fission. I cannot rule out a black silicon/carbon hyperEarth although I admit that is an extreme. The iron core will be stiff and not rotate much, so: its magnetic field ends beneath the high-G surface.

The planet will also own a protolunar disc of silica rings - tho' mostly outside the field (this is not Jupiter). Most of this debris should collapse into a mainly-silica moon-system with less carbon - at first. As we talk potential, these moons could well get to Mars-size. If there be more than one moon, and the extras are inbound of this moon: expect intense tides. I don't know a cooldown from 1000 K allows enough ice for a super-Europa but we'll see much Io. As for soot, I expect full nanodiamond in this haze; that'll rain down on the planet and on its (outer!) moons to form their dusty surface.

We shall never see this faraway system in its final glory. But other, closer stars might have system with a planet-with-moons like this already.

ASASSN-21qj

Two worlds collided, 1800 light years away. Title: "A planetary collision afterglow and transit of the resultant debris cloud", by Matthew Kenworthy at Leiden, crediting also a number of astronomers both professional and amateur. I don't have Nature access so I'm piecing stuff together here.

As an amateur myself - at blogging - first, a review of the media. Science Daily transmitted a press-release from Bristol. Whoever's running their social-media needs to be hauled into the main office and told to do better, starting with relaying the title of the research which they didn't do. Science Daily meanwhile should quit relaying such releases if the releases don't release the bare minimum.

The Grauniad probably has the best recap although I dislike their term "citizen scientist". Also you have to look up the astronomers themselves to tell us, explicitly, that US-citizen Arttu Sainio was the scientist in question.

As a heat event, this was spotted by Neowise's infrared. WISE is a wide-ranging observer so only catches this one every 300 days or so, per the astronomers. JWST should be able to see more.

December 2021 is when the star tagged "ASASSN-21qj" suddenly dimmed. This occasioned the amateur social-media data-hunt; Sainio noted a brightening 900 days prior which WISE did not catch. That flash was 1000 K (maintained to this day per Grauniad) and 4% as luminous as its very star. Said star, it happens, is young: 300 My. That flash, then, is considered a crash. I don't think the team could get angular-separation directly, from this low-parallax, but the period is about 2.5 years so they just Keplered it based on a one-solar-mass barycentre - several to tens of Earth masses at 2-16 AU. Namechecked as other possible collisions: NGC 2354–ID8, HD 166191, and V488 Persei.

At that separation from a star, these were proto-icegiants, in the sooty sector. Their 1000 K mixer is now a spinning object potentially hundreds of times the size of Earth per Grauniad. I believe that "potentially" refers to the Hill Sphere.

BACKDATE 10/12

The Borneo plate

On topic of old tectonics, the Dutch found some north of their old haunts at Borneo. Actually north of the Philippines too - back then, 120 Mya, the Philippines were south-latitude.

The Dutch call it "Pontus" but shouldn't. I'd use some term from Taiwanese Aboriginal. h/t Science Daily which also fell down on the job inasmuch as they didn't include the images, which images had the year on them which the text did not.

BACKDATE 10/11

There was an Older Dryas too

Leeds posted a release to "EurekAlert!"; this is reported in Newsweek and Drudge. Along with AD 774 and 993, and with 660 BC, a double-Miyake occurred in 14,300-year-old tree rings. That is actually "BP" so, 12350 BC (nearexact).

That's end-of-ice-age, but long before either Dryas. I don't think any human recorded it. It would have made for a mighty aurora. It is so long ago that the dead wood had already started on the fossilisation process; the pictures look like the outer, younger rings are already rock. Wood gets scarcer the longer back we reach.

The postglacial ring event lines up with beryllium in ice so - cosmic. Since it's in spaaace nobody down here knows what causes these things. Usually assumed is coronalmass ejection from our own Sun. Could be nearby supernova.

Also listed is another event 12060-11960 BC - which interests me more. This has more scholarly agreement: our Sun wasn't protecting us, from cosmic rays generally. Thus: a Maunder-type solar minimum, as (un-)sparked the Older Dryas which started in ice 12075 BC. We don't normally hear much about that compared to the drama of the Younger. Before them both was an "Oldest", the Heinrich 1 stadial - although I don't know we have the treerings for that.

I take it that when we were warming up, but not warm-enough for all the Canadian and European ice to have melted yet, we were more vulnerable to Maunders. Maunder's actual little-ice-age was bad enough.

Time to leave Seattle: AD 2500

After the growing season, that is after September, AD 923; some unleafed trees died in what is now Seattle. This is the sort of thing for which I like Seleucid reckoning: during early AG 1235.

The researchers have this exact date - and season - because of Miyake. Miyake spikes at the A_iD 774 and 993 have made-possible a range of exact dates for tree death; e.g., tracking from the latter, the Markland settlement AD 1021.

The most-famous winter 'quake in Cascadia was that which the Japanese recorded 26 January 1700 (AG 2011) - as a tsunami, from nowhere. Did the Japanese record anything for AD 923/4?

Just getting a half Seleucid year is excellent for judging when the next quake will strike. Seems to be eight centuries. So the region has five more to go.

BACKDATE 10/11 in light of the 4.3.

Chickens roosting

Armenians did not always inhabit Artsakh. The lake Sevan, in the late-antique Parsarmenia, was about as far as Armenians ventured - and their language, as of Juanshir's tenure, was already divergent from the Grabar. Juanshir might even have been the one who enforced Grabar upon those breakaways, and further into territory of Adharbad(?): Atropatene to Greeks, Adharbadegan to Iranians.

The region did acquire an Armenian-speaking majority. The remaining Azeris, outside Artsakh, were conquered by Turks and no longer speak the Iranian language they'd had. Whilst it was under Tabrizi and Russian protection, its population was protected when their cousins in Ottoman Kurdestan... not so much.

The USSR split the southern Caucasus into a "republic" and then to three republics and "Autonomous" enclaves. The Soviets followed the great Western tradition of drawing nonsensical borders. In the Caucasus, one border went through "Azerbaijan" with Artsakh, perhaps, on the wrong side. The region revolted in the early 1990s and became an independent republic recognised by nobody.

After much misrule over in Armenia, Azerbaijan recently found its opportunity to contest the rebellion. The Israeli premier Netanyahu, no stranger to misrule, supplied Azerbaijan with material. Azerbaijan won the war; Artsakh is now Azeri-Turk. There are refugees. Some people outside the Caucasus care. Netanyahu doesn't.

Even before last night, not all Israelis think that Netanyahu is all that great. It also does not appear that Israel's support for a Muslim aggressor against a Christian nation has endeared them to the Muslims. I wonder today if Netanyahu wishes, at least, that he'd kept some of his armaments closer to home.

ISRAID 10/28: Cerno reminds us.

Citizen or scientist: pick one

Let us retire the term citizen scientist. I've seen that around here-and-there; a book at Nederland's library noted the term.

Heinlein teaches that the citizen is a loyalist to his sovereign, sometimes loyal-opposition should the sovereign stray from his/their mandate. Scientody is how the citizen and the sovereign determine how, intelligently, to exercise that mandate. "SCIENCE!" happens when we have policy-driven data (powerpoint).

You can do research, or you can influence policy. You cannot - ethically - do both. You can be a citizen, and a scientist; but not at the same time.

BACKDATE 10/12: I should have noted this months ago.

The Letter to the Magnesians, and 1 Clement

On the hunt for the Lachrymose Letter in Patristics, I raised that 1 Clement might still know it. Next stop (skipping Luke) is Ignatius of Antioch. He likewise cites 1 Corinthians but not 2 Corinthians as far as I read him; but - for Paul - I find nothing outside the ambit. I did find other considerations...

The longer Magnesians in the third chapter - as plus to the version most agree upon (the "medial": pdf) - goes on a long excursus upon examples of Biblical characters opposing their Divinely-appointed superiors; among them, Dathan and Abiram. Hannah further noticed that Magnesians 8, in the longer version only, gets around to citing 2 Corinthians. I suggest that the longer version had recourse to 1 Clement 4:10-12.

This does not narrow down very much. 1 Clement was highly regarded in the Church to the point it entered into some New Testaments - most-famously Alexandrinus. This is Alexandrian - for Paul; Byzantine for the Gospels. Griesbach considered its Catholic Epistles as "Western" - I must assume, D/06 Claromont; either way, "Western" often signifies collections before the later canons. Despite the Byzantine decisions, "Western" texts hung on, in the West, hence the name. As late as the Middle Ages, Ibn Khaldun noted 1 Clement in some (Sicilian?) codices.

Since Streeter, I understand it is scholarly consensus that Ignatius although not as fluent in the Old Testament as was 1 Clement, had inherited 1 Clement's "ecclesiology". The letter to the Romans seems conversant with 1 Clement 54-6. For Magnesians 3, I couldn't rule that catena of Biblical exemplars out.

Hannah thought the pericope early too, albeit still forged. He argued that the longer Magnesians is of AD 140. This got forcefully rebutted by Brown four years later; Brown seems consensus as of 2017.

1 Clement as the new Lachrymose Letter

Paul wrote a "Severe Letter", also called the Lachrymose Letter, to the church in Corinth; 2 Corinthians is its followup. This letter of tears, everyone knows, is not 1 Corinthians. Much ink has been spilled over whether it lies incorporated into 2 Corinthians or, if so, how. Weak Among The Weak proposed a reconstruction of this letter of tears - in outline, based upon seams in 2 Corinthians, rather than speculating that it is (somehow) misplaced into chs. 10-13 or wherever.

Key here is where 2 Corinthians speaks of Moses. The new Law is written ... on Paul's heart, as fragile as slate tablets.

More boldly this essay thought that the Testaments of the Patriarchs had recourse to the lost letter. Either that, or that Testamental author had found a pseudepigraphic reconstruction of something like WATW's; either will do for our purpose. Did anyone else use this?

This Letter would have to be early, since the reconstructed text isn't (as far as I know) ever directly cited as Pauline, in Patristics. Here is a database of Patristic quotation including 1-2 Corinthians; we might look for allusions to "2 Cor.2.2" which are inexact and actually in a Lachrymose context.

That database is large even if restricted to the first couple centuries. To narrow our search, one must ponder what sort of writing should resort to the Lachrymose Letter.

For (counter-)instance: Justin. Justin's most-famous works are two Apologies (to pagans) and one Dialogue (with a Jew). Famously these don't refer to Paul's work very much and never directly. Now, this absence is overblown but, never mind that. We care about the Corinthian correspondence in Justin's work. To that: Paul was here writing to his own church. Especially with the Lachrymose Letter we should hardly expect Justin to be airing out internal dirty laundry, to others.

More promising is a letter as went out from authorities to defective churches as had been following a similar path as Corinth had, in Paul's day. Oh lookie, we have exactly this from AD ~60: "1 Clement". To Corinth herself!

If WATW is right, then we need textual parallels like the Testaments had made. We seek allusions to Moses at Sinai when the golden calf is mooted. We are also looking for writings upon stone and/or hearts. 1 Clement does talk Moses lore; but its main focus is upon envy - when Israel denied Moses' right to kill that Egyptian, down to Dathan and Abiram (4:10-12). The calf is not noted...

...at first. 1 Clement will get to that later. To that end, the following excerpts are suggestive to me:

• 17:5 Moses was called faithful in all his house, and by his ministry God judged his people Israel by stripes and punishment.
• 43:1 Moses' sacred books
• 53:2-3 Moses!... thy people... have made unto themselves molten images. / The servant is bold towards the Lord: he asketh remission for the people, or demands otherwise that he himself should be destroyed together with them.

Moses is consistently the `obed-El for 1 Clement. 5:5-7 poses Paul as the model of patience over envy. 47:1f then cites 1 Corinthians at the envious ones.

So - 1 Clement 2:8, The commandments and ordinances of the Lord were written on the breadth of your heart. That looks like Romans 2:14-15, or 2 Corinthians 3:1-3. Neither of these are exact. Romans 2:14-15 concerned the "nations" outside Torah who, to the extent they followed Torah precepts, must do that by instinct. Corinthian Christians by AD 60 knew better. 1 Clement 2:8 looks here like the Lachrymose Letter, which WATW poses as more-directly Paul's heart as a tablet on which the Law has been inscribed but which, like the stone tablets given to Moses, was capable of being broken. As sent to Corinth, Corinthian hearts should by now be like Paul's; 1 Clement moans they were like Paul's.

If 1 Clement be a witness to the Lachrymose Letter as WATW has it, we must still explain why 1 Clement doesn't cite it as directly as 1 Clement cites 1 Corinthians. I can pose possibilities. One is that WATW's reconstruction really was severe (and emo), more severe than Paul himself entirely endorsed, hence the need for 2 Corinthians. Also, anyone collecting the set could see that 2 Corinthians abrogated the Lachrymose Letter, thus not commending that medial letter to future direct quotation except in special occasions (like that of 1 Clement).

On the other hand: if 1 Clement alluded to the Lachrymose Letter, this explains why we don't see allusions to 2 Corinthians. Corinth is now in the grip of a generation as require a Lachrymose Letter of their own. Further, once Corinth had 1 Clement, as AD 170 bishop Dionysius reports they had (as by "Clement"!), those church elders were venerating 1 Clement. They had less need for Paul's letter anymore.

The meteor-theory strikes again

James Kennett at Santa Barbara is back (again) with the Dryas impact theory 10900 BC. With him: Sweatman, Tankersley, and - in spirit - Loeb. Against them: the vulcanologists.

Sweatman is not a coauthor in the paper, but is credited; Tankersley gets more credit than he deserves. Loeb is quietly ignored.

Kennett ignores the Greenland crater, which has nothing to do with this, instead looking to Sweatman's Black Mat over the Assyrian jazira itself. This time they got shocked quartz.

Personally I am more on the side of the vulcanologists. Still: I must disassociate this blog from certain of their more Science-Be-Settled! claims, like this 2011 mess. I do want to point out that a volcano if powerful-enough might eject chunks of rock high enough that they come back to us as meteors so, why can we not kiss and make up.

Be interesting to see how the vulcanologists (and Colavito) respond. UPDATE 2/29/24 ... given Kennett's problems.

POxy-4009

Brent Nongbri, an international treasure, last weekend did a palaeography upon POxy-5575. Nongbri has concluded that #5575 isn't just in similar handwriting as #4009 - it is by the same hand. So: let us investigate #4009.

#4009 got some press in 1993 but the Jesus Seminar didn't pay attention to it, so I had no idea about it. The text is... slight; there's a recap at this forum. Its base-text requires much reconstruction, more so than #5575's; the most-popular reconstruction of the more-legible side is on the basis of 2 Clement. Since we are on topic . . .

This blog has suspected that 2 Clement was using a narrative independent (mostly) of the canon. The reconstruction of POxy-4009 implies, strongly I think, that this scrap is that narrative behind 2 Clement.

#4009 is in a first-person narrative which narrator is in Christ's inner circle. He corresponds to 2 Clement's Peter. There is some interconnexion with a "Western text" of Luke - in Luke-Acts studies usually that means Bezae, not the Claromontaine tradition.

I remain unsure that #4009 came out of the same book as did #5575. But. That these MSS were written out by the same person (male or female) suggests that these texts were, at least, in Christological alliance.

There is no interplanetary fly-by cruise

If you have seen Aniara or Avenue 5, the conceit of the genre is the interplanetary space-transport - for humans, some sailing first-class. Much is owed to Titanic lore (we do not speak of that awful gay-pr0n feverdream 1899). Lately Erik Wernquist has offered what looks like an advertisement.

Wernquist implies a one-way trip. His ship goes to Neptune - at least. The brooding musical score and the elderly protag hint at Aniara - a ship headed to outer space, at high velocity, to die. Maybe we're looking at the prequel to Pandorum. Maybe our protag is the architect who is observing his life's work, so we're watching the leadin to Passengers. (I do wish they'd shielded the ship better. Protag don't care but Jennifer Lawrence will care.)

For my part I concede the desire among some for a return journey, probably to Earth. These visitors will, still, be staying at Deimos or in Venus-orbit until the next launch-window opens - which will be some weeks. Returnees will be taking a different shuttle. Staying on a cycler after its first run is like sitting on the ski-lift on its way down - but worse. (Maintenance-crew? ... monks?)

The question is whether one can plot out cycler-like trajectories as go to Venus, and then Mars, and back. This blog hasn't done that yet - but it has done the next best thing, which is a Hohmann transfer from Venus to Earth and then to Mars. The Earth/Mars Hohmann is, I vaguely recall, the VISIT cycle, so - it'll end up near-enough Earth again after a few Earth/Mars synods.

In of itself, I admit: that's not the cruise-line. It doesn't get back Home (here, Venus) in particularly short order. But. I believe it a fair proxy for potential cruise-lines.

What is going on is that our planets are not perfect nor even longterm Laplacians; they are in no resonance. The Hohmann non-cruise between Venus to Earth and to Mars opens up seven decades from now - but will not last. The same logic must hold for any future multiplanet cycler.

This means that the interplanetary liner is, itself, impermanent. The first-class passengers have to get off somewhere, or else spin in space for years on end. As to the ship - assuming the company doesn't want to lose it, it has to be drydocked. At Deimos maybe.

This further implies that cruises as swing by Jupiter or Saturn, also, must dock at some station over those massive planets. There is no, "swing by Jupiter, gawk, go home", option. Enjoy your months at Callisto.