A canon is not a law

A few days ago (h/t Jihadwatch), Todd Aglialoro 'splained how canon law is not shari'a. He's right.

Jews own a religious law, some say (or joke) several; Christianity claimed to have overthrown this. Some modern scholars (Patheos*koff*) argue that Luke's project went toward an anarcho-syndicalist set of Christian communes. That might run at odds with Luke's overall structure of the Spirit exiting Jerusalem and settling upon Rome, not (then) Christian in any way. Much as this particular blog might look askance at Luke's work - and at his interpreters; we are addressing Aglialoro who inherits Luke's Christendom. This post follows them to address the Roman church; not that in the Greek or Slavic worlds and certainly not in Syriac.

Here Christendom and Romanitas had fused sufficiently in the fourth century AD that Theodosius, and over a century later (and more-so) Justinian, were able to create Roman laws which were also Christian laws. Full circle - right?

Well, no. Justinian may be a saint for some (I understand he remains popular in Russia) but out here West, he's considered a tyrant. Because he was. This before we get to Rabbûla or to Shenûte. (Leaving Donatus aside.) Rome has always refused Byzantium's claim to be a "new Rome". We never lost our own Rome.

Also, in the west, and more so among the eastern Syrian "Nestorians": we have Dyotheletism. Religious law does not exist. We have religious canon. That is an old word - Akkadian, I hear - which means "standard". A canon defines what is a Christian and how the Church is to conduct itself. A nation may embrace Christianity and govern according to its ethic. That nation would form its own laws - in accordance. Not in extrapolation.

Future Failed Senatorial Candidate El-Sayed gets one cheer (as an Egyptian, he might even know Shenoute, although I'd be surprised if he knew Rabboula) for reminding us that Christians - at times - have imposed [monastic] canons as laws upon dubiously-willing citizens. Thing is, Catholics don't do this. "Muh Inquisition". No, dude; that was a state, and the Church tried to temper those excesses.

Where is the Dyotheletism in the Egyptian Sunni tradition? - more to the point, where is the notion that law exists outside the clerisy?

The bilateral log

Following sex - and predation; Kimberella (a mollusc) evolved bilateralism 558 Mya, also we hear of tubeworm Calyptrina. That is when different organs handle food intake and postfood exhaust. Petrov is on it, relating Julien Kimmig and Russell Bicknell.

(Some actual crap is involved in Kimmig-Bicknell being behind a paywall.)

The first Vendian/Ediacaran bilaterals did not drop deuces as the fossilisation process has (yet) preserved. These deuces get to the record in the Cambrian 538.8 Mya: microscopic at first, then growing to make the log. As it were.

Turns out that smaller animals produce smaller doodoo, such that these nutrients simply got BACTERIA'D. As noted I cannot read K-B but Petrov would imply that the first bilaterals weren't so different from the anemonai on this much. A mat of slime was laid down, by all. This didn't sequester all that much carbon, so the seas were still CO₂-rich and poor in oxygen.

Over the Cambrian, a feedback loop kicked in whereby larger animals dropped deuces that sequestered more carbon at a time. Oxygen increased, allowing for larger animals with their longer guts. The elder mats were meanwhile churned up by bottom feeders like the trilobites.

So far this just looks like more evidence for the Cambrian Explosion as explosion. We can still use that old just-so story Blink of an Eye to explain how certain animals suddenly were able to feast, and for their descendents to grow. To predationmaxx, said the book.

The DIRT ROCKET

ToughSF pointed Thursday the 27th to 2007's DOI 10.1063/1.2722266. No link b/c X. 50V for 50-100 I_sp.

I'd consider it for docking a smol robot with some regolith of low G (like you-know-where), then moving on. Meh. Hope it's cheap anyway.

Really we should be making colonies from the dust on this rubble. The colonies refine the dust into oxygen, and into something that can react with oxygen. That offers a lot more impulse and, also, thrust. They say this might work even on our Moon. As for Bennu et al. I'd just scoop it all and move it somewhere less dangerous.

Warp drive roundup

Poring through a random month of this 'ere blog, I ran across Erik Lentz then Alexey Bobrick and Gianni Martire. Most of this got trashed by Santiago, Schuster, and Visser (SSV) the following year. So, five years on - last May - Caroline Delbert ran a pulse-check. Seems there's been some activity in what has become, uggh, a "community".

We are here interested primarily in the warp-bubble, where the prospective colonists don't age as the colony ship travels at a sedate subrelativistic pace. Interstellar space operatics may refer to José Rodal last year for Alcubierre's negative-energy (see below). The bubble remains attractive if only because relativistic risks all what we saw in Passengers (this went by red giant Arcturus 33.78 ly, which implies something like .76C). Such theories also claim not to require negative energy.

Last February, Hamed Barzegar, Thomas Buchert, and Quentin Vigneron got on all warp cases (BBV). SSV had a few errors, but not such as vindicated the warp core Doors.

The BBV classification under which Bobrick-Martire falls is the R-Warp model, definition III.3. These satisfy the "restrictions" R1+R2+R3b+R4(+R6); developing Barzegar and Buchert last year. R4 is new here: asymptotic flatness. The Natário metric is a subset; here to assure a globally hyperbolic spacetime. That had been an assumption of Alcubierre 1994; so a rule had to be thought up where this could be assured, done in Choquet-Bruhat–Cotsakis 2002 BBV's "theorem IV.3". BBV have their own theorem IV.7 such that superluminal R-warp models can never be hyperbolic.

But hey. I remind my readers I wasn't asking for tachyon beams. We just wanted a bubble that got to Arcturus in however-many-external-decades without the hibernation-poddery. José Natário has been saying all year his bubble - hyperbolic - is subluminal. (The BBV paper reports he was arguing differently in earlier years, but maybe those weren't R-Warp.)

Nah. SSV's big stinkbomb to the R-Warp, even the slow one, was that it violates the null energy condition. BBV can only affirm SSV here, as "theorem IV.34". As asymptotically flat (R4), theorem IV.20 says they violate the dominant energy condition too; that is, that the energy can't be negative.

BBV point out that some of these R's in the R-Warp models may be lifted, as long as we are in Gedankenexperimentland; but engineers, not such Landsers, will find difficult to explain how they can. Same problem has afflicted Alcubierre when he said "just use negative energy bro".

An T. Le follows up, providing the service of explaining the four energy conditions, not just "null" and "dominant". These are pointwise inequalities on the stress-energy tensor contracted with timelike or null vectors. Any vio represents an exotic fuel (or, per BBV - "fantastical") like the negative energy - which we don't have. He also submits the WARPAX, eigenvalue tests on the various tensors. Sure, per SSV the fuels all suck; but how bad do they suck? Oddly Rodal's drive seems to suck least, considering it remains superluminal. But that might be because Rodal was willing to clarify his model to Le, in personal communications.

Since May, An Le has gone on to evaluate several fuels' "source consistency"; all subluminal [and] positive-energy. They all suck in newly found ways, not so much interior as on the boundary with our nonfantastical universe.

Maybe call it "the Lewinsky Drive".

Barnard's Rossby

Barnard's classical habitable-zone estimation relies, I think, on this 2013 paper. But a couple years ago, we were looking into Alfvén systems. This is before we even had planets around Barnard's star, Gliese's #699. It turns out this star - as "GJ 699" - had convection calculations in 2018. For its colour V − Kₛ ≈ 4.99 (thank you copilot), logτ=2.07. Convective turnover should be 124 days based just on their own calc of 130.4/1.05.

We do have to correct the Rossby, given rotation period has since 2018 been updated from 130 to 140 days. That pushes Rossby to 1.13.

Plugging into Equation 5, 17.46 * (1.13^0.41) = 18.36 Sol radius maximum; 17.46 * (1.13^0.03) = 17.5 Sol radius minimum. In terms of semimajor, 0.08-0.085 AU. Barnard e - outer, 0.0382 AU - rolls well inside the minimum.

Like Barnard's inner worlds didn't have enough problems. A ten-day "HZ" planet would still be fried. 22.6-to-42-day on the other hand standeth a chance out to 0.13 AU.

Barnard's inclination

Copilot is telling me we don't have Barnard's inclination. It rotates too slowly and it doesn't offer sunspots. What we do have are constraints on the inner four planets. They are resonant and seem to have been there for - well, ever, as far as Earthlings can tell. This suggests they formed there.

From Table 3 in that paper I see minimum sini≈0.4 across the board. That is 0.4115 rad; or 23.6° up to not quite 90 (90 is edge-on which means transits as we don't see).

Going to the Basant paper which confirmed the four, the Msini limit on a HZ (then-calc'ed 10-42 days) planet is a paltry 0.57 M_⊕. But. sini of 0.4 would allow up to 1.425 M_⊕ out there.

We cannot yet rule out an Earthlike in the HZ. Well, as earthlike as an airless tidally-locked rock can be.

Skyhooks of silica

I suspect these two goofs felt comfy with CNTs only because they already knew all this stuff was (literally) not going to fly in the 2000s. In these the 2020s, Jensen instead has figured upon anhydrous silica with no "Griffith flaws" (per Copilot). This is a cable we should be able to spin from Lunar regolith and ship up to space for cheaper. Let's see what this buys us.

Jensen was targeting 13.8 GPa of pure laboratory SiO₂ so ρ = 2.2. The deltaV equation √(13.8*2/2.2) = 3.54 km/s. That'll get you to Hohmann for any porkchop of Mars - or for Venus (2.8 km/s); but the next-good Byrnes-Longuski cycler to Mars is "6S9" which is terrible.

If we could stationkeep a tether-hook at STL1, this would work for a faster cycler to/from Venus: the 2L4. Venus herself could not use a 13.8 GPa cable. Both of us can however run the 3-0-2-9 cycler - in the 3.4+ km/s range on either side - and then we can keep both tethers in high-orbit.