The Thceyn’s birthing takes the inverse shape of ours. A new Thceyn forms as a thin, flexible membrane around the Thceyn world. Micrometers thick at first, it grows thicker and stronger and tighter until it strains to hold the world in. The convex pressure of the world entire starts hurting its vast, flattened organs. Its birthing organ starts spiraling into the world-barrier. It looks a bit like a drill that can unfold into a grappling hook. Having started at one point of the world, where its parent flew up to and punctured the world-barrier so that the Thceynling could gestate in the safe, sterile vacuum of space, it now starts digging back through the world-barrier at the antipode. The creature’s body starts loosening from the umbilical pole.
Slowly, the Thceynling drills through the birthing pole of the world. Its readying body has blotted out the stars and clouded out the sun. Astronomers have folded away their telescopes for the week. When a birth is coming all the daytime world knows it from the caustics: dappled sunlight races across the surface of the world, lensed through the rippling heaves of the Thceynling’s body. A giant finger flicks globs of light in through the kitchen windows and across the wide boulevards of the Thceyn world, as if they all live at the bottom of a swimming pool.
At the birthing pole, the hooks come out and fasten on the inside of the world. A pause. It is moving on pure instinct through all this, and that instinct is saying that it’s safe to let go. It obeys a little, and the world crowns. The Thceynling convulses around it in a panic, one great contracting muscular ring. The folds bunched up around the emerging world are thick, and the habitations right underneath it are doused in artificial twilight.
Everything is new to the Thceynling, and it is terrified to push more. But it is also in pain. So with a great shudder that shakes the world, it tightens and loosens, three or four times. In its final heave it extrudes the rest of the world, and they fall apart from each other.
If its hooks loosen now in its convulsions it will fly away and be lost forever, as will the nutrients it took from the Thceyn world to become. Everyone hopes this will not happen. It is the means by which the Thceyn world becomes smaller and smaller, and will one day end. When the world began the surface was close to the world barrier. It was easier to poke through it to put out a zygote, which would then grow quickly from the nutrients that were readily available from the surface. But then as the world lost mass and shrank down, the Thceyn people evolved flight to reach the shell. Nowadays they use aircars for convenience, and one day the aircars will be the only way, for the distance will be too far to cover with wings.
The Thceynling ripples in space like a wreath of fine tissue paper blown out of the world, waves working through its body and tangling it a little in itself. But its hooks hold. The various lights of space rush in through the world-barrier. Hurriedly it squirms in through the birthing pole, a fabricky mass of flexible muscle and organs. It starts coagulating on the inside, folding in on itself with instinctive neatness, matching its various organs up to nestle against each other in the correct order. This is a teaching opportunity: doctors bring out their protegees to the roofs and point out regularities and irregularities.
When it is done, it has eyes, layers of light-catching organs that filter out brightness and different colors and synthesize their findings into one picture. It can see the world now. It is not so sure about this. Its throat, now fully composed, lets out a bray of dismay.
Its parent has swum out to the ocean under the birthing pole to catch it. It has spread itself out into a thin, vast sheet, and is making an encouraging bioluminescent display on its welcoming fins. Come! The water is warm, and I will catch you.
The Thceynling squirms uncertainly. The surface of the world is dotted with other lights and it has some vague sense of being watched. Some vague sense that any cowardice would be quite public. The briefer its hesitation the better. Besides, it does not like dangling all bunched up here like an overgrown chrysalis. The high-frequency parental lights, which demarcate the boundaries of the catching body in the water, are looking pretty good.
It spreads itself wide to blunt its acceleration, unclenches its hooks, and falls into the world.