Time

longer a line of sight connecting us. The communication is one-way now, through the Feynman radio—”

“Then what do we do?”

Cornelius shrugged. “We wait. The firefly has onboard autonomy. It’s programmed to investigate its own situation, to return what data it can.”

A blur, a wash of light, passed over the corner of the screen before the image stabilized.

Now Emma saw a battered plain, slightly tipped up, receding to a tight, sharp horizon. The craters and ridges were low and eroded, with shadows streaming away from the viewpoint.

“The light’s too poor to return any color,” Cornelius said.

“What’s the light source?”

“Floods on the firefly. Look at the way the shadows are pointing away from us. But the use of those floods is going to exhaust the batteries fast. I don’t know why it’s so dark…”

“Cruithne looks older,” Emma said. The firefly was panning its camera across an empty landscape; the shadows streamed away. “Those craters are eroded flat, like saucers.”

Malenfant said, “Micrometeorite impacts?”

“It’s possible,” Cornelius said. “But the micrometeorite sand-

blasting must be slow. I assume we’re still out in intergalactic

space. Matter’s pretty thin out here.”

“How slow?”

Cornelius sighed. “I’d say we’re farther into the future by several orders of magnitude compared to the last stop.”

Emma asked Malenfant, “What’s an order of magnitude to a physicist?”

Malenfant grimaced. “A power often.”

Emma tried to take that in. Ten times seventy-five million. Or

a hundred, a thousand times…

The viewpoint was shifting. The landscape started to rock, drop away, return. Slowly more features — ancient, eroded craters — loomed up over the horizon.

Cornelius said, “The firefly is moving. Good.”

“The Sheena,” Emma said.

The beach ball was sitting on Cruithne’s surface once more, complex highlights picked out by the firefly’s light. Within, a shadow was visible, swimming back and forth.

“How extraordinary,” Cornelius said. “To see a living thing across such immense spans of time.”

“She looks healthy,” Emma said. “She’s moving freely; she looks alert.”

“Maybe not much longer,” Malenfant growled. “That damn water ball will freeze.”

“Do you think she understands any of what she is seeing?”

“I doubt it,” Cornelius murmured.

Now that she looked carefully Emma saw that the shadows the floods cast on the golden ball weren’t completely dark. The shaded areas were lit by some deep red glow.

“There’s something in the sky,” she said. “A light source.”

The image started to pan away from the cephalopod, jerkily.

More Cruithne craterscape slid across their field of view.

Then the landscape dropped out of sight, leaving a frame filled with darkness once more.

‘The firefly’s panning upward,” Malenfant said. “Come on…” And a new image resolved. “Oh, my,” he said.

At first Emma could make out only a diffuse red wash. Perhaps there was a slightly brighter central patch. It was surrounded by a blood-colored river of light, studded here and there by dim yellow sparkles. But the image kept breaking up into blocky pixels, and she wondered if the shapes she was per-

ceiving were real, or artifacts of her imagination.

“We’re right at the limit of the optical system’s resolution here,” Cornelius said. “If the firefly is smart — there. We switched to the infrared detectors.”

The picture abruptly became much brighter — a wash of white and pale pink — but much more blurred, in some ways more difficult to see. Cornelius labored at his softscreens, trying to clean up the image.

Emma made out that great central glow, now brightened to a pink-white ball. It was embedded in a diffuse cloud; she thought she could see ribbons, streamers in the cloud, as if material were being dragged into that pink maw at the center.

The core and its orbiting cloud seemed to be embedded in a ragged disc, a thing of tatters and streamers of gas. Emma could make out no structure in the disc, no trace of spiral arms, no lanes of light and darkness. But there were blisters, knots of greater or lesser density, like supernova blisters, and there was that chain of brighter light points — yellow before, now picked out as bright blue by the enhancement routines — studded at regular intervals around the disc. Filaments seemed to reach in from the brighter points toward the bloated central mass.

“It looks like a Galaxy,” Malenfant said.

Emma saw he was right. It was like a caricature of the Galaxy she had watched just minutes before. But that central mound was much more pronounced than the Galaxy’s core had been, as if it were a tumor that had grown, eating out this cosmic wreck from the inside.

Cornelius was consulting his softscreen, asking questions of the hierarchy of smart software that was poring over the images. “It probably is a Galaxy. But extremely old. Much older than our Galaxy is at present — even than when we saw it at the Sheena’s last stop—”

Malenfant said, “Is it the Galaxy? Our Galaxy?”

“I don’t know,” Cornelius said. “Probably. Perhaps Cruithne entered some wide orbit around the center. Or Cruithne might have had time to reach another Galaxy. There’s no way of knowing.”

“If that’s our Galaxy,” Emma said, “what happened to all the stars?”

“They’re dying,” Cornelius said bluntly. “Look — all stars die

Our sun is maybe halfway through its life. In five billion years or so, it will become a red giant, five hundred times its present size. The inner planets will be destroyed. The sun will span the sky, and Earth will be baked, the land hot enough to melt lead…”

“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.