“But there will be other stars,” Emma said. “The Galaxy reef.”

“Yes. And the smallest, longest-lived dwarfs can last for maybe a hundred billion years, a lot longer than the sun. But the interstellar medium is a finite resource. Sooner or later there will be no more new stars. And eventually, one by one, all the stars will die. All that will remain will be stellar remnants, neutron stars and black holes and white dwarfs, slowly cooling.” He smiled, analytic. “Think of it. All that rich, complex dust and gas we saw before, locked up in the cooling corpses of dead stars…”

Malenfant said grimly, “And then what?”

“And then, this.” Cornelius pointed. “The wreck of the Galaxy. Some of the dying stars have evaporated out of the Galaxy. The rest are collapsing into the great black holes — those blisters you see in the disc. That central mass is the giant black hole at the core. Even in our time it has around a million times the mass of the sun. And it’s still growing, as star remnants fall into it.

“You see the way the matter streams are straight, not twisted? That means the central hole isn’t rotating. Wait.”

“What now?”

“The firefly is returning the relic temperature. The Big Bang glow. Well, well. It’s down to one percent of one degree above absolute zero. A little chilly.”

“What does that mean?”

“It means I know where we are. Or rather, when. The universal temperature is declining as the two-thirds power of time.” He hesitated, and when he spoke again, even he sounded awed. “The data is chancy. But the consensus of my software colleagues here is that we’re around ten to power fourteen years into the future. That’s, umm, a hundred thousand billion years — compared to the universe’s present age, which is around twenty billion years — -five thousand times as far downstream as at present.” He nodded, as if pleased.

The numbers seemed monstrous to Emma. “I can’t take that in,” she said.

Cornelius glared at her. “Then try this. These powers of ten are zoom factors. With every extra power of ten you zoom out another notch, shrinking everything. You see? This downstream universe is so old that the whole history of our world — from its formation to the present — compares to this desert of future time as… let me see… as your own very first day of existence compares to your whole life.”

Malenfant, looking stunned, his mouth tight, just shook

his head.

“So this is the end,” Emma said. “The end of life.”

“Oh, no.” Cornelius sounded surprised. “Not at all.” He

pointed to the clusters of brighter light around the rim of the

galactic corpse. ‘‘‘‘These seem to be normal stars: small, uniform,

but still glowing in the visible spectrum.”

“How is that possible?” Malenfant said. “I thought you said

all the star stuff was used up.”

“So it is, by natural processes,” said Cornelius.

“Oh. So these stars can’t be natural.”

“That’s right.” Cornelius turned to Emma, his pale eyes shining. “You see? Somebody must be gathering the remnant medium, forming artificial birthing clouds. Somebody is still gardening the Galaxy, even so far downstream. Isn’t it wonderful?” “Wonderful? The wreck of the Galaxy?” “Not that. The existence of downstreamers. And they still need stars and planets, and warmth and light. They are still like us, these descendants of ours. Maybe they even remember us.” He rubbed his face. “But those stars are small and cold. Designed for longevity. Their worlds must be huddled close — probably gravitationally locked, keeping one face in the light, one in the dark.”

“Good God, Cornelius,” Malenfant said. “That’s a lot to deduce from one smudgy image.”

“I’ve been thinking about this all my life,” Cornelius said. “Plotting the survival of humankind, of intelligent life, into the far future. Mind games played against an unyielding opponent — time — with the laws of physics as the rules. And the farther downstream we look, the more we are constrained by the laws of physics. The future has to be like this.”

Now the image lurched. The wrecked Galaxy slid out of the frame, to be replaced by a glaring wash of light. The firefly adjusted its receptor to visible light, and the floodlit plain of Cruithne was revealed once more.

There was no sign of the golden bubble, or the firefly patiently towing it.

“The Sheena has gone,” Malenfant said immediately. “She must have gone back to the portal again.”

“Christ,” Emma said. “She’s trying to get home.”

“But she’s only succeeded in traveling farther downstream,” said Cornelius. The image lurched again as the firefly began to toil toward the portal once more. “And so, it seems, must we. The firefly doesn’t know what else to do.”

Emma found she was making a fist, so hard her nails were digging into her palm. “I don’t want to see any more.”

“I don’t think there’s a choice,” Malenfant said grimly.

The image of the portal expanded out of the camera’s field of view, and once more that deep black, blacker than galactic night, confronted Emma.

There was a flash of electric blue.

Another black sky, another Cruithne. The patient firefly crept forward, shining its own fading light over the crumpled surface of the asteroid, seeking the Sheena.

Emma would not have believed that the ground of Cruithne could look more aged than it had before. And yet it did, its craters and ridges and scarps all but invisible under a thick blanket of dust. As the firefly labored Emma could see how its pitons and cables kicked up great sprays of regolith.

The three of them watched in somber silence, oppressed by time’s weight.

“How long, Cornelius?” Malenfant asked, his voice hoarse.

Cornelius was studying his data. “I don’t know. The relic temperature is too low to read. And…”

And there was a dawn, on far-downstream Cruithne.

Emma gasped. The sight was as unexpected as it was beautiful: a point of yellow-white light, sunlike. The light rose in clumsy stages as the firefly labored toward it. Shadows of smooth eroded crater rims and ridges fled across the smooth landscape toward her, like bony fingers reaching. It was so bright it seemed to Emma she could feel its warmth, and she wondered if somehow this long journey through time had looped back on itself, returning her to the dawn of time, the birth of the Solar System itself.

But, she quickly realized, this was no sunrise.

A glaring point was surrounded by a tilted disc, glowing red, within which she could trace a tight spiral pattern. And there seemed to be lines of light tracing out from the poles of that central gleam, needle-thin. Farther out she saw discs and knots of dull red matter, much smaller than the big bright core object. The central light actually cast shadows through the crowded space around it, she saw, shadows that — if this was a galactic-scale object — must have been thousands of light-years long.

It was oddly beautiful, a sculpture of light and bloodred

smoke. But it was chilling, inhuman, even compared to the last

grisly galactic vision; there was nothing she could recognize

here, nothing that looked like a star.

“Our Galaxy?” Malenfant asked.

Cornelius studied his data. “Perhaps. If it is, it’s extremely shrunken. And I’m seeing objects away from the disc itself now: a scattering of low-energy infrared sources, all around the sky. Stellar remnants, I think.”

Malenfant said grimly, “What you said. Evaporated stars Right?”

“Yes.” Cornelius studied the screen. “At a guess, I’d say ninety

percent of the objects in the Galaxy have evaporated away, and

maybe ten percent are gathering in the core object.”

“The black hole. That’s what we’re seeing.”

“Yes. We’ve come a long way, Malenfant, and our strides are

increasing. These processes are slow….”