Trope-a-Day: Endless Daylight

Endless Daylight: A property of more than a few worlds in the Empire. Some, like Eurymir, because they’re tide-locked, and the noon pole always points at the sun. A similar situation applies to the hexterranes of Coricál Ailék, which are oriented such that “up” is always sunward, and the danglehabs of Esilmúr, in which down is always sunward.

In other cases, it’s because the world inhabits a binary system. Eliéra, for example, has this periodically – in a manner of speaking – because for half the year, the summer, it is located between the two suns, and as such each side of the world receives some insolation. (Although, obviously, not identical – it still has a day-night cycle; it’s just that it alternates between full daylight and a red-tinged twilight that’s bright enough to read by, somewhat more so than a full moon.)

Lumenna-Súnáris System (5): Eliéra

I/4. Eliéra

Class: Sylithotectonic (simulated)
Orbit (period): 0.993 au (361.1075 T-days; 333.33 local days)
Orbit (ecc.): 0.023
Radius: 5,000 miles – special
Mass: 5.614 x 1024 kg
Density: 6.2 g/cm3
Surface gravity: 0.94 g

Axial tilt: n/a
Rotation period: 26 T-hours

Black-body temperature: 265 K
Surface temperature (avg.): 284 K

Atmosphere: Standard atmosphere.
Atmospheric pressure (sfc.): 0.94 atm
Hydrographic coverage: 60%

Satellites: 1 major (Seléne); 1 moonlet (Elárion).

Ah, yes, Eliéra. Homeworld of the eldrae. The jewel at the center of the Empire, and therefore the universe. The shining center from which the light of Order, Progress, and Liberty beams out into the galaxy.

And, curiously enough, not actually a planet at all.

It’s a Precursor-built Big Dumb Object. (Well, okay, technically it’s actually a Big Terrifyingly Smart Object, but that’s the accepted term/acronym…

…yeah, you know what? From now on, hereabouts, I’m redefining BDO to mean Big Damn Object, which strikes me as much more in the spirit of the thing.)

But anyway: it’s not a planet. It’s a flat disk – well, okay, not quite. It is almost a flat disk, with smoothly curved edges because while it’s 10,000 miles in diameter, it’s only 200 miles in height. Those smoothly curved edges mean that you can, in fact, sail right around the edge of the world to the other side and never bump into an actual “edge”; or at least you could were there not a giant perpetual storm where the two sides’ weather systems slam into each other in the way. It’s also almost flat because the builders wanted it to look flat, meaning that it’s actual gross shape is slightly convex, such that it looks flat after the refractive index of the atmosphere is taken into account. It spins like a flipped coin along a spin axis tangential to its orbit, which provides it with a day-night cycle.

At this point, several questions ought to be leaping to mind:

1. How does it keep its shape?; and
2. Those figures for volume/mass/density don’t look right.

I mean, Eliéra, as you would expect from its gravity, masses about 0.94 what Earth does. Its crustal density is a little heavier than Earth’s density, but not by much. (6.2 g/cm3). And yet its volume, being a disk 10,000 miles across by 200 thick, is only about 1/17th of the Earth’s.

You should definitely, at this point, be wondering how the hell that adds up.

Well, that would be the lump of Mystery Matter™ down at the core layer that lets it hold shape under its own weight, and which is also responsible, it is believed, for the physics-defying weird-assitude of its gravity field.

(Said weird-assitude, as brought up here as the divide between Terrestrial and Celestial Gravitation that had entire generations of physicists and astronomers beating their heads on things and complaining about how much they hate special cases, is that said Mystery Matter™ does not obey the inverse-square law. Gravitational attraction to it is governed, instead, by the Because We Are World-Constructing Sufficiently Advanced Precursors And We Bloody Well Say So Law.

The practical result of this is that if you are in low Eliéra orbit, say a 10,100 mile orbit (i.e., 100 miles above datum), your stable orbit will skim the atmosphere in what is basically a disk shape orbit matching the gross shape of the “planet”. If you are in high Eliéra orbit, contrariwise, say a 100,000 mile orbit, your stable orbit will be a perfect near-circular ellipse, just as it would be around a perfectly normal planet, and your altitude above datum will vary accordingly. Stable orbits in between occupy shapes in between, exactly as if there was some meta-law changing the BWAWCSAPAWBWSS Law smoothly and continuously into the inverse-square law depending on how far away from the Mystery Matter™ you happen to be.

The consensus on this is that it is (a) space magic, and (b) fucking weird.)

3. How the hell does the geology/ecology work?

Mechan Ically.

Well, okay, not entirely. The Precursors who built it were very clever geotects and ecotects who arranged for as much to happen in a perfectly natural way as they could, but that couldn’t apply to everything. It’s very hard to have planet-like geological processes without a mantle and molten core, for example.

So, instead, they buried down in the big sealed core layer (that contains the Mystery Matter™) a giant massively-parallel array of nanocomputers – this being why it’s a Very Smart Object Indeed – complete with a whole ecological maintenance team in the form of “mechal elementals”, what its first civilizations assumed were nature spirits of one kind or another, that do the work of filling in the essential missing bits.

Which is to say: it’s a giant machine that worlds just as as hard as it can.

4. Does it have seasons? How does it have seasons?

Because binary system.

For half the year Eliéra is between its suns, and night is – instead – a faintly red-tinted as-bright-as-the-full-moon twilight, and both sides of the disk receive insolation at once. For the other half of the year, it’s opposite to the second sun, and its primary washes out its secondary’s contribution during the day while nights are actually dark, peaking at midwinter when Lumenna actually occults Súnáris.

The actual difference in solar input is very small indeed, but when chaotically amplified through feedback loops in the “planetary” atmohydrosphere, that’s how it has seasons.

5. Something else?

Of course, while I’m trying to answer the common but-hows, I’m too close to this to really have a good grasp on what they might be, so if you have more, please feel free to ask in a comment.


As for its satellites, it has two, both far enough out to be in comfortably conventional orbits.

I/4/a. Seléne

Class: Selénian
Orbit (period): ~325,000 miles (15.77 T-days)
Orbit (ecc.): 0.01
Radius: 1281.2 miles
Mass: 1.35 x 1023 kg
Density: 3.30 g/cm3
Surface gravity: 0.20 g

Axial tilt: 4.77°
Rotation period: 15.77 T-days

Black-body temperature: 265 K
Surface temperature (avg.): 246 K

Atmosphere: None.
Hydrographic coverage: 0%.

Seléne is Eliéra’s major moon; it is very much like our moon, except for being somewhat more distant, and somewhat fatter, although curiously enough the apparent size from the surface is fairly similar.

Relatively low metal, silicate-rich, lots of fun stuff in its regolith, first to be colonized, you know the drill here. In later years it comes with helium-3 mining briefly, autofacs, cities, resorts, far-side observatories, and many millions of embodied sophonts living up there.

I/4/b. Elárion

Class: Gelidaceous
Orbit (period): ~1270000 miles (170.79 T-days)
Orbit (ecc.): 0.31
Orbit (inc.): 136.2°
Radius: 238.6 miles
Mass: 5.052 x 1020 kg
Density: 2.14 g/cm3
Surface gravity: 0.012 g

Axial tilt: 51.4°
Rotation period: 0.46 T-days

Black-body temperature: 265 K
Surface temperature (avg.): 246 K

Atmosphere: None.
Hydrographic coverage: 0%.

Did I say conventional orbits?

Elárion is Eliéra’s weird-assed moonlet. An obvious extrasystemic capture (just look at that strangely-inclined, retrograde orbit), it’s a little (asteroid-classed, by the book; just smaller than Ceres) gobbet of ices and tarry organics that somehow wound up as a far and a distant moon.

From space, the surface seems oddly pink-red, due to said tarry organics. From Eliéra’s surface, of course, it’s barely visible, but those with good eyes looking hard enough in the right place can make out a tiny, tiny red dot in the sky.


On Cartography

But first, merry rebirth-of-the-solar-deity day to one and all.

So, let’s see.

So far as maps of worlds go, such as one might be able to make biomes out of…

…well, this may take a little while. For values of little while equal to “I have a map of Eliéra that’s over ten years old and which is almost entirely wrong…


A world bearing little or no resemblance to Upperside Eliéra.

…and the maps of everywhere else are even worse.”

So before I even think about that, it’s time to redraw all the maps. Which I am working on, starting with this one. But let’s just say for now that we won’t be talking about planet surfaces any time soon.

But I am busy putting together the definitive data on the Lumenna-Súnáris System above the atmospheres, which I might have for you tonight if everything goes comically well, or tomorrow if it doesn’t.

And on we go.


Trope-a-Day: The Plague

The Plague: In the ancient pre-Imperial past on Eliéra, the Gray Contagion, a wasting disease with the same sort of morbidity and mortality as the Black Death.  It was responsible for one of the two great prehistoric population diebacks there (the one not caused by the astrobleme/ensuing Winter of Nightmares), and is thought to have originated as a leftover Precursor bioweapon.

It’s Sometimes Darkest Before The Dawn

For the most part, it doesn’t matter when you travel to see any of these by either the galactic or the local calendar. The Twin Worlds, the Shells of Thalíär, and the rest offer their spectacle to the curious eye at any time. Eliéra is the exception that proves this rule. You should visit Eliéra during its summer months, and preferably as close to midsummer as can be arranged, because that is when the Eliéran sunset is at its most spectacular.

The binary sunset of the Lumenna-Súnáris system is not in itself particularly spectacular; after all, binary – or higher-order – star systems are common in the inhabited galaxy, and indeed, many colonies are themselves located upon planets of binary systems. Everyone’s seen a binary sunset.

Eliéra’s, however, is unique, due to the combination of the unique parameters of its system, the width of the flat world, and the system its Precursor builders set up to provide it with its day-night cycle. During the months of high summer, the suns rise and fall in antiphase. As Lumenna (the system primary) sets, the full glory of the star-lit dusk appears for a matter of minutes, only, before distant Súnáris rises pale and wan, ushering in a faintly red-tinted twilight in which the stars fade, but do not vanish – until the morning, when Súnáris sets again, giving a dawn, too, of darkness and stars before the full light of day once more. This dual “star-flash” cannot be seen anywhere else in the known galaxy, a minor wonder of a greater work.

– The Twelve Wonders of the Galaxy, Ademone Kirvin-ith-Kirvin


The Shibboleth of Science is “That’s Odd”

“Academician. Academician.” The foundry master wiped his hands on his leather apron, and waved at the looming bulk in the back of the workshop. “Your sky-tube’s coming along to plan. Just got the wire-wrapping on today. The woodwright’s’ll be here tomorrow to get the quarter-boards on her, and your chymist seems satisfied. Though I’d appreciate it if you’d have him do the filling elsewhere; the way he was talking, that stuff you’re using shouldn’t be within a mile of our fire-works.”

“It shouldn’t, or most other places, indeed. We’ll not be filling her until we’re in place to fire her. And we should, then, be ready to take delivery by the 19th?”

“We’ll have her ready for you. What’s all this about, anyway? I’ve built the like before, but nothing half this large.”

“We’re going to find out where gravity breaks.”


“It’s one of the more troubling problems in natural philosophy,” the second Academician put in. “The difference between Celestial and Terrestrial Gravitation. You see, ever since records began at the Starspike, and it was shown that…”

“We don’t need all three thousand years,” the first interrupted.

“Um, yes, anyway, after a lot of observation and even more theorizing, most of it wrong, the Starspike’s skywatchers figured out that the planets, and us, and the Shining One, and its planets, and all the moons are all moving around each other in lovely, sweeping ellipses as they fall together and always miss. And after much computation, Siao Callaneth produced his Lemmas and declared that if you postulate an attractive force that’s in proportion to their masses and inversely proportional to their distances, all the numbers come out right.”

“Yeah, but that’s true down here, too. We use his lemmas all the time in structures.”

“Ah, but it’s only true sometimes down here. Up there, if you assume that a world is a point, it works. Down here, if you assume that an object is a point –”

“If it’s homogenous, otherwise it’s an offset point.”

“If it’s homogenous, yes, thank you, it works. Between objects, if you have heavy objects and sensitive pendulums. But if you drop something here, what direction does it fall?”


“Down, yes. Straight down. And we’re not above the center of the world, are we?  But if we drop something, anywhere, it falls in a nice straight line perpendicular to Eliéra’s notionally-flat surface, even though the center of all the world’s mass is thousands of miles over there. It falls straight down here, it falls straight down in Mossstone, it falls straight down even in heathen Indimór-on-the-Rim, for all that the Lemmas say that the world’s gravity should drag everyone there sideways off their feet, if not crumple the edge of the world up like tissue paper, rock not being all that strong. And that is Terrestrial Gravitation, the damned exception that’s been inexplicable ever since the Shadow-watcher made note of it when proving the world was flat in the first place.”

“Eliéra behaves both ways, you see. Down here, things fall straight. But if it behaved that way celestially, we’d orbit – well, we wouldn’t move in one of those beautiful ellipses, and the moons probably wouldn’t stay up. Somewhere, if you go far enough up, everything changes. And watching Skybreaker here fly is going to tell us where.”


Vol. 6: Mechal Elementals

Among the first known of all nanorobotic machines were the so-called mechal elementals, the maintenance mechanisms of Eliéra. While the common conception of that artificial world is that its ecology is maintained and guided by the computation and matter editation layers buried in its core, this perception is false – these are merely the most prominent elements in a complex system.

These nanorobotics have existed for the entire history of the eldrae on Eliéra, and from long before, having been part of the world since its construction by the Precursors. This is reflected in their names and taxonomy, since long before robots, mechanicals, or even simple clockwork automata were dreamed of, the ancient eldrae knew them as elemental spirits, emanations of Sylithandríël, eikone of the natural world, and Her first six children/souls, the Six Elemental Dragons.

The traditional taxonomy of the mechal elementals reflect this origin, as they are classified under their presumed elemental aspects, including such elementals as the silt spawn and stone mothers, responsible for counteracting the long-term secular erosion of the mountains; the cloud shepherds and smoke sylphs in the air; wave undines and river carvers; soil churners of the fields and the dryads of the forests; the magma krakens that churn the fires below and the flame swallows that govern their release; and the gemlords and ore ants known to generations of miners and tunnel explorers.

In the modern era, of course, we know all of these to be nanomechanical systems, part of the planetary maintenance architecture answering to the central computation layer. That said, since these systems are now overseen by the archai Sylithandríël and Her subroutines, the ancient theological view is now arguably more true than it was at its inception; and, indeed, the archai maintains the validity of the old lore of elemental beckoning, bargaining, and abjuration that the ancient eldrae painstakingly discovered to deal with the alien animating intelligences of “wild” mechal elementals before the Transcend, despite the ability to communicate directly via gnostic link.

Many of the mechal elemental designs have been repurposed for use as ecopoesis tools elsewhere. This volume describes both these, and also those mechal elementals most commonly seen in the wild and in history, along with both the modern and ancient protocols for interacting with and commanding them.

First, we describe the elementals of the Air, the emanations of the Air Dragon…

– Concordance of Robotic Systems and Animating Intelligences, 221st ed.