Saturn's Children

Long-Lost Sibs

ERIS IS ONE of the largest dwarf planets in our home solar system, and also one of the chilliest and most isolated, for it spends most of its time well outside the Kuiper Belt, drifting in the darkness beyond the frosty edges of planetary space. It’s also spectacularly hard to get home from; its orbit is steeply inclined, almost forty-five degrees above the plane in which the rest of the planets and dwarf planets orbit. Unless you’re going to hitch a ride on one of the starships they build and launch every decade or so, this is the end of the line.

These attributes make it an ideal place of exile for those who don’t want anything to do with the state of the i

There are certain downsides to life on Eris, of course. Did I say it was cold? I don’t mean upgrade-your-hydraulic-fluid and dress-up-warm cold; I mean it’s cold enough that there are lakes of methane on the surface, and in the depths of winter (which lasts, oh, about sixty standard Earth years) they freeze solid. If you go on the surface in winter without boots and gloves, you will last maybe fifteen minutes before you begin to succumb to the cold. In summer it’s even worse — the pools evaporate, giving the planet a thin atmosphere of chilly vapor that pools in low places and can suck the warmth from your torso before you can say “hypothermia.” Eris (and its tiny, close-fleeting moon, Dysnomia) makes Callisto look like a tropical resort.

It’s dark, too. I mean, night-dark. If you don’t know the sky intimately well, you can look up at the stars and be unsure whether it’s night or day. Sol, from Eris, is as bright as a full moon on Earth. Distant supernovae outshine it.

It’s like this on all the planets of the Forbidden Cities.

People cluster in spherical cities that rise above the shadowy permafrost on a myriad of prickling insulator legs, held in place by tension wires against the occasional tremor triggered by heat pollution from the fusion reactors they rely on for energy. In the century-plus since Eris was settled, we have already raised the temperature of its lithosphere by several degrees, just as we’ve thickened the atmosphere of Callisto a thousandfold; if this goes on, the more a

As to why the cities are forbidden…

I BECOME AWARE of dim blue light and a curious repetitive rasping noise, like a factory full of malfunctioning motors that are slowly grinding away their bearings. I feel light. The gravity here is about a tenth of Earth’s, lighter than lunar, and the air has the heady tang of copious free oxygen. It smells of a complex melange of weird organic molecules, bicyclic monoterpenes and hexanols. I’m warm — warmer than I’ve been since I was last in a pressurized dome on Mars, warm enough for molten water to flow freely. I’m on Eris, of course (where else?) but for the rest of it…

I turn my head to look around. The surface I’m standing on is prickly and brown, strewn with debris and rubbish that stick into the skin of my (bare) feet. All around me brown-stemmed branching structures like the dendriform molecular assembler heads in my techné — only much, much bigger — stretch upward, bearing jagged, asymmetrical greenish black panels or sensors. I’m surrounded by green goo! I realize, tensing uneasily. These things around me are plants. Solar-powered self-replicating organisms that split carbon dioxide into oxygen and, um, something else. (Please excuse my lack of depth; I’m a generalist, not a specialist. Why bother learning all that biochemistry stuff — or how to design a building, or co

I’m dizzy with fresh impressions. I’m wearing the same elaborate aristo trouser suit I left Callisto in, nearly four years ago, although someone seems to have laundered it thoroughly in the meantime. Thanks, whoever you are. And the sloping floor beneath my feet is covered in dead decaying bits of green goo — eew! I extend my heels hurriedly. Overhead there’s a dark blue dome, brightening at one side, which is obscured by the dendriform replicators, the trees. The weird rasping noise continues, and it’s getting on my nerves. Things unseen move in the foliage, rustling, and there’s a faint breeze. This must be what Earth was like in the old days, before our Creators died out.

“Welcome to Eden Two, my lady,” a gruff voice rumbles behind me.

I manage not to jump out of my skin. “Very picturesque. Where are the guests kept?” I ask sharply, covering for my discomfort. A memory, not quite mine ( Juliette’s doing, a ghost of a recollection echoes at the back of my mind) tells me I should be expecting a guided tour of the facility. I’ve been here for some time — days, it seems — walking around in a fugue state, with Juliette doing the driving.

“We’ll get you there in due course,” the voice assures me. “Eden Two is over two kilometers in diameter, to provide a realistic territorial domain for the constructs to roam in. There are over six thousand prokaryotic species, two hundred types of macroscopic plant, and thirty different strains of insect in Eden Two. In fact, building it was even more of a challenge than re-creating the climax species…” He drones on like this for some time, while I try to get over the shock of discovering someone else has been wearing my body for the past few days. He’s explaining the baroque features of the entirely artificial biosphere that surrounds me — a biosphere, I gather, which took nearly a century to painstakingly construct, piece by piece.

What happened to me? The last thing I remember with any clarity was Juliette’s hand, slotting the broken slaver chip back into my socket. Which is impossible, because Juliette is either back on Mars or dead, certainly not sharing a cramped berth with me on an express ship bound for Eris. I rub the back of my neck and feel no inhibition about fingering the top of the soul chip. Okay, so I’m on Eris, and somehow nobody’s noticed I’ve been — what? Asleep? Suffering from a split personality? That might make sense if… I try to touch the other soul chip nestling above my hairline, and it’s as if an invisible hand swats my wrist away. Fingers, sis, Juliette admonishes me.

Where’s Granita? I ask my ghostly sister. It feels disconcertingly as if she’s standing right behind my left shoulder — even though I know if I look around I won’t see her. What happened?

Granita asked me to check out the biome in person. She’s got other business to take care of down in Heinleingrad.

Shit. It’s the soul chip; I’ve been wearing Juliette for more than five years now. You’re not meant to do that — they’re for transferring memories and impressions, and it takes a few months, not years. So I’ve started talking to myself, have I? Or has it gone even further? There are odd stories, about personality disorders that can crop up if you spend overlong patterning a dead sib’s soul on your own brain. I really ought to remove that chip, but — Don’t worry about that. I’m just a figment of your imagination — as long as you keep your hands off my chip, she adds, ominously.