There is a place between the stars where the stars themselves are a rumor. Look outward from it in any direction and the nearest sun is one pinprick among ten thousand, no brighter than the rest, offering no heat, no direction, and no name. Through this place, at a speed that would frighten anything capable of fright, falls a planet.
It was thrown. Four billion years ago, in a system that has since forgotten it, a larger world swung too close and flung it outward, and it has been falling through the gulf ever since, cold as the gulf, dark as the gulf, a knot of iron and stone and frozen gas with no sun behind it and none ahead. It has crossed distances no eye has measured. It will cross more. By every definition that could matter to anything living, it is dead.
It carries something.
A moon. Small, round, wrapped in ice, circling the dark planet on a path that is nearly a circle, and the nearly is everything. Lit by anything, it would be blue. Nothing lights it. Starlight too thin to cast a shadow slides across its face and finds no color, so the blue is a property it has kept to itself for four billion years, the way a stone kept in a drawer keeps its color.
The surface is perfect. Out here there is nothing to hit it. The gulf holds a few atoms per cubic centimeter, and the rare stray rock has ten thousand years of emptiness to cross before it arrives. So the ice lies smooth to the horizon, pale, ridged in long low welts where it has cracked and healed, and cold enough to shatter like glass. Nothing has ever crossed it. Nothing has fallen here and left a mark.
That is the outside. Go down.
The first mile is ice so cold it has forgotten it was ever water, hard as the rock beneath it, ringing faintly when the ridges shift. Then the sound changes. At three miles the ice is warmer and it moves: slabs the size of counties slide and lock, and their grinding is the loudest sound on the moon and has never been heard. Fissures open in the dark and seal. Warm ice rises through cold ice in slow blisters. This is the flex. Once each orbit the moon swings close to its planet and the planet’s grip tightens; once each orbit it swings wide and the grip slackens; and the moon, which is stone at heart, gives a little each time, a few meters of give across a thousand miles of body. The give rubs. The rubbing warms. Four billion years of being squeezed. Four billion years of warmth wrung from a stone by a hand that has no idea what it is holding.
At twelve miles the ice thins to slush, then brine, then, without ceremony, there is no more ice.
Ocean.
Lightless. Serene. Blue in the same withheld way as the shell above it, blue with nothing to be blue for. It fills the whole hollow of the moon beneath the ice, sixty miles deep, salt and sulfur and dissolved rock, warm the way a body is warm, from the inside out. Currents move through it slower than anything you have ever felt, rising over the warm places and sinking over the cold, a circulation that takes a century to close. Water is liquid here, in a universe that forbids it almost everywhere.
At the bottom, rock. The core of the moon, iron and olivine, cracked by the same flex that warms the ice, and through the cracks the ocean leaks in and comes back changed. Water meets hot rock; the rock takes the oxygen and gives back hydrogen. Chimneys grow on the seafloor, white towers of carbonate a hundred feet high, breathing warm alkaline water into a cold acidic sea, and where the two waters meet across a mineral wall thinner than skin there is a difference in charge, and a difference in charge is the oldest form of power there is.
Over the rock, on the chimneys, in the pores of the mineral: a skein. A thin film of carbon compounds, lipids, amino acids, the fragments of the fragments of what could someday be a cell. Every ingredient is here. Heat from below, wrung from the stone by the planet’s grip. Water, the solvent, liquid against every odd. Rock, to supply the iron and sulfur and nickel the chemistry needs before it can begin. The gradient, to drive it. Time, of which this moon has had four billion years and will have, falling through the gulf, untold billions more. The dark, which has never once interrupted. All of it lies on the seafloor like a kit of parts on a workbench, waiting for a hand to assemble it, and the only hand out here is the planet’s grip, which tightens, and slackens, and tightens.
Out of the benthic dark, from behind the tallest chimney, something drifts into the warm water. It has fins. It has a lateral line, and a lidless not-eye that has never had anything to see, and a mouth that opens and closes. It is, unmistakably, a fish. It hangs in the current for a moment, lazy, unbothered. Then it beats its tail once, against the pull, and goes where it wants.