SIerra Foxtrot 15

SF thoughts. Mostly concerned with my attempts to work out zled astronomical nomenclature and related astrogational matters, and some military stuff.

• Turns out 37 G. Gruis is too young, with the high estimate for its age being 4.1 billion years. So it won't work for the khângây sun. (I started looking into it because it's a double star and I don't know if those can support life, though the other is just an M-type red dwarf.) Considered putting them at 5 G. Capricornis, sandwiched between its two Neptune-like planets. But then decided no, I'll put them at α Mensae, the dimmest α-star in Earth's sky. The latter is a bit old at 5.4 billion years old, but mÕskoi, now being λ Serpentis, is 5.25 billion years old (taking the average of the estimates). That's not that much older than 4.54 billion years; both planets are drier than Earth, so maybe it took them longer to form life.
• Decided to continue pursuing the zled celestial-coordinate naming after all. Realized I can express everything in microradians. At first I considered writing them in base-32, AKA duotrigesimal. See, there are 32 letters in the Zbin-Ãld alphabet; their normal numerals are letters of the alphabet—because they use acrophonic numerals, where each digit is represented by the number's first letter, except marked to indicate it's a number, the way Greek numerals are. Duotrigesimal, with only letters and not numerals (because it would be too confusing to use both), is a natural binary-derived code for them, the way hex is for us.
  
  The entire sky can only ever be up to 6,283,185 microradians, a full circle rounded to the nearest whole unit. That's only a five-digit number in base-32. And the Third Fundamental Catalogue of 1937, compiled to create a celestial reference-frame, is only accurate to within an arcsecond, so for "traditional" (i.e. "pre-space colonization") names of stars I think a microradian's nearly 5 times that precision is plenty. (Incidentally, I was actually wrong about the Bonner Durchmusterung system; it actually just gives the declination degree and then the order the stars were counted, starting from 0 right-ascension. Anyway, see below.)
• But then I tried it out. The numbers were horrible, complete gibberish, like reading off the default password of a wifi router. Thought better of the whole duotrigesimal thing; now it's just decimal.
  
  I had had them calling the stars by the names of constellations I worked out—when they were at 59 Virginis, though, I think, not even 18 Scorpii (it's been a while since there's been a convenient tool for generating alien sky-maps, like the now sadly defunct "Extrasolar Skies" website was)—and then a number. Given how the Durchmusterung designations work, I just list the stars by one of fifteen constellations (or asterisms?) that occur at various points along their celestial equator (like a zodiac, but that's the ecliptic), and then by their declination; there are fifteen because 6,283,185 is divisible by both three and five.
  
  Given how zledo arrange large numbers (paired digits, not trios or quartets like most Earth languages), the number of microradians in the declination sounds okay—Sol's declination, for example, is 1.939186 radians, or 1,939,186 microradians. In speech that comes to "one million ninety-three myriad ninety-one hundred eighty-six", or, in practice usually, just "one ninety-three ninety-one eighty-six".
• Turns out I might need the zled artillery to start using the topological defect warheads at a smaller scale than I'd planned, what with militaries now already working on plasma shields to protect things from the concussive force of explosions. Then again you might just have to get somewhat closer hits, because the plasma shields don't stop anything except the pressure-wave from blasts; with anti-tank fire (the context the shields are usually mentioned in), you probably want a relatively direct hit anyway, since the main thing we use against tanks nowadays is "long rod" explosively formed penetrators. (Actually you'd probably be protecting things a lot less armored than tanks, like AFVs, with the shields—we don't lob ordinary, big-blast artillery shells at tanks, it's not a very efficient way to destroy them.)
• Oddly, English actually has a vocabulary for dealing with vigesimal (base-twenty) and duodecimal/dozenal (base-twelve), as well as decimal (I actually realized this working on my Pathfinder setting). For vigesimal, the numbers are the same from one to nineteen, and then you say "onescore". Forty is twoscore, then threescore is sixty, fourscore is eighty—all the way to nineteenscore, three hundred eighty. Then, four hundred is "twentyscore" (yes, real term), and then eight hundred (for example) is "two twentyscore". Things are a bit clunkier in duodecimal/dozenal, because the term for one thousand seven hundred twenty-eight is "great gross", which is inelegant. Personally instead I'd go (on the model of "twentyscore") with "twelvegross". E.g., three thousand six hundred twenty-four—3624_X, 2120_XII—is "two twelvegross one gross two dozen".
  
  I'm not sure how either one goes for powers above score squared or dozen cubed—the dozenal equivalent of a myriad might be "dozen twelvegross", though, the way the thousand-superbase equivalent is "ten thousand". (In a D&D setting it's not an issue since numbers above the thousands come up very seldom in practice.)
  
  Interestingly there's a system halfway between dozenal/duodecimal and decimal, the "long hundred", where a "hundred" is defined as twelve tens not ten tens, and a thousand is twelve times ten times ten (or ten "long" hunreds, I guess?)—with ten tens being "tenty" and eleven tens being "eleventy". Tolkien did not coin the term "eleventy-one". That was actually the norm in West and I think North Germanic languages up to quite recent times; there are medieval glosses of Latin documents, for those languages, that specify that Latin defines one hundred "tenty-wise". The advantage, of course, is that incorporating the twelves increases the number of factors you get to work with; if I had my druthers the metric system would be ten long hundreds ("long thousands", an actual term) not ten "short"/"tenty-wise" hundreds. (Incidentally, sixty has most of the same advantages in this regard that the long hundred has—which is probably why Mesopotamian numbers are sexagesimal.)
• Of course, for actual astrogation (I am very pleased that Blogger or my browser, whichever one is checking my spelling, knows that word), zledo don't use anything as provincial as equatorial coordinates derived from their homeworld: they use galactic coordinates. Those are the same between Earth and Lhãsai, except they actually center theirs at Sagittarius A*, and their longitude is 273,957,125 nanoradians (15°41'47.7126") to the west of ours (through λ Serpentis not Sol), and their latitude plane ("equator") is 2,094,395 nanoradians (0°07'12") south of ours. That, and their coordinate system does rotate over time—the way a planetary one does—because it's utterly bizarre that it currently doesn't. (I would dearly love to know the intellectual pedigree of that decision.)
  
  I think in my future the humans will also have decided that their galactic coordinate system should rotate; I'll have to figure out the year they decide that. Then I just go with the number of years separating that from 2000 and multiply it by 5.7 milliseconds-of-arc (no not "milliarcseconds" that's stupid). I like 2140; if it's 2140 then the zled longitude is 273,957,122 nanoradians (15°41'46.9146") west of ours, because its coordinate changes from 0°07'12" S, 15°41'47.7126" E, to 0°07'12"S, 15°41'46.9146" E.
  
  The only other issue is what unit to express their "altitude" from the galactic center in. For that I figure I'll define something as a "unit circle" and then express distances as a fraction of that. Unfortunately the size of a galaxy is quite literally nebulous, but I could for example work with the current estimated radius of 129,000 light-years. λ Serpentis is 29,346.864055 light years from the galactic center, which is 0.22749507019 galactic radii, or, say, round it down to 0.227495 (a precision of about an eighth of a light year), which is 45,499/200,000—"four myriad fifty-four hundred ninety-nine twenty-myriadths", in zled terms. (I could also maybe do some multiple of the thickness of the thing; the galaxy is very far from spherical, after all.)
• In a star-system, on the other hand, zledo just project a latitude/longitude system out from the star, with its equator at the system's ecliptic, and define north, south, east, west, up, and down relative to that (up and down being "away from the star" and "toward the star", same as they are when longitude and latitude are defined relative to a planet instead). Though they measure latitude and longitude in a full circle not a half one, and in radians not degrees. Think they just define altitude in actual length units, though they could treat some distance (say, the astropause or the inner termination shock) as a unit-circle and express distances as a fraction of that. But it's really hard to find information on the astrosphere of other stars, so I'm not doing it that way.
• Realized I need some way for zled armor to dump the energy when it gets hit. Decided to have a series of fans suck air through, on planets (doesn't have to be breathable air—the suit's respirator-system is completely separate), and sort of "wings" with radiators, in space. The latter has the advantage of looking cool and science fiction-y, with an actual justification. You could probably lower the efficiency of the armor by hitting it with something that'll gum up the air-intakes, but zledo aren't going to sit still while you do that (plus it's still composite metal foam wrapped in boron nitride nanotubes, as far as human weapons are concerned). The radiator "wings" are more vulnerable, but they presumably mainly use those for EVAs, not fighting. (If you're getting shot at by small arms in a vacuum, odds are something is very pear-shaped anyway. Most of the things someone's going to shoot you with in space will vaporize you, no matter what armor you have.)
  
  Might also need to work in that the zledo came up with this metamaterial armor because they switched to lasers to defeat composite metal foam, since lugging around the kind of ammo that can beat it ballistically is a hassle; the new foam is still only effective against lasers out to the ranges where full-powered rifle rounds are effective against our highest levels of body-armor. I'm also switching the graphene layer of their armor (and uniforms) to boron nitride nanosheets, for the simple reason that graphene's strength decreases when you stack multiple layers of it, while that of the BN nanosheets doesn't. The BN ones also have, I think, higher thermal conductivity, and seem to be less chemically volatile than graphene. (Also apparently BN nanosheets can be used for adsorption of chemicals—like odors, which give away zledo's feelings, which they consider immodest—which means they don't need a separate layer for that, just for anechoic effect.)