She smiled.
I can hear you smiling, Lieserl. I’m smart like that. You enjoy being the hero, don’t you?
“Maybe just a little.” She let her smile broaden. I’m casting shadows onto the Sun. Not a bad monument.
The uppermost level of the Northern’s habitable section was a square mile of rain forest.
The four air-scooters rose through a cylindrical Lock. Mark found himself rising up, like some ancient god, into the midst of jungle.
The air was thick, stifling, laden with rich scents and the cries and hoots of birds and animals. He was surrounded by the branchless boles of trees, pillars of hardwood — some extravagantly buttressed — that reached up to a thick canopy of leaves; the boles disappeared into the gloom, rank on rank of them, as if he were inside some nature-born temple of Islam. The floor of the forest, starved of light by the canopy, was surprisingly bare and looked firm underfoot: it was a carpet of leaves, pierced by Lock entrances which offered incongruous glimpses of the cool, huge spaces beneath this sub-world. Fungi proliferated across the floor, spreading filaments through the leaf litter and erecting fruiting bodies in the shape of umbrellas and globes, platforms and spikes hung about by lace skirts.
On a whim, Mark rose through a hundred feet alongside the rotting carcass of a dead tree. The bark was thick with ferns and mosses which had formed a rich compost in the bark’s crevices. Huge, gaudy orchids and bromeliads had colonized the bark, drawing their sustenance from leaf mold and collecting moisture from the air with their dangling roots.
He drew alongside a wild banana. Its broad, drooping leaf was marked by a line of holes on either side of the midrib. Mark lifted the leaf, and found suspended from the underside a series of white, fur-coated balls perhaps two inches across: nomadic bats, sheltering from the rainfall of this artificial forest.
There was a motion behind him; he turned.
Uvarov had followed him, and was now watching appraisingly. “Each day,” Uvarov intoned, his face long in the gloom, “an artificial sun will ride its chariot across the glass sky of this jungle-world. And machines will pipe rainfall into artificial clouds. We’re living in a high-technology realization of our most ancient visions of the Universe. What does the fact that we’ve built this ship in such a way tell us about ourselves, I wonder?”
Mark didn’t answer. He pushed himself away from the tree, and they descended to join the others, just above the forest floor.
Louise slapped the bole of a tree. She grinned. “One of the few real objects in the whole damn ship,” she said. She looked around. “This is Deck Zero. I wanted our tour today to end here. I’m proud of this forest. It’s practical — it’s going to be the lungs of the ship, a key part of our ecology — and it has higher purposes too; with this aboard we’ll never be able to forget who we are, and where we came from.”
She looked from one to the other, in the green gloom. “We’ve all come into this project from different directions. I’m interested in the technical challenge. And some of you, with Superet sympathies, have rather more ambitious goals to achieve. But we four, above all others, have the responsibility of making this project work. The forest is a symbol for us all. If these trees survive our ten centuries, then surely our human cargo will too.”
Serena Milpitas tilted back her head; Mark followed her example, and found himself peering up at the remote stars through a gap in the canopy. Suddenly he had a shift of perspective — a discontinuity of the imagination which abruptly revealed to him the true nature of this toy jungle, with empty, lightless space above it and a complex warren of humans below.
Garry Uvarov said, “But if the Superet projections are correct, who knows what stars will be shining down on these trees in a thousand years?”
Mark reached out and touched a tree bole; he found something comforting about its warm, moist solidity. He heard a shrieking chorus, high above him; in the branches above his head he saw a troupe of birds of paradise — at least a dozen of them — dancing together, their ecstatic golden plumage shimmering against the transPlutonian darkness beyond the skydome.
A thousand years…
Dark matter could age a star.
The photino knot at the heart of the Sun lowered the temperature, and thereby suppressed the rate of fusion reaction. Naively, Lieserl supposed, one might think that this would extend the life of the Sun, not diminish it, by slowing the rate at which hydrogen was exhausted.
But it didn’t work out like that. Taking heat energy out from the core made the Sun more unstable. The delicate balance between gravitational collapse and radiative explosion was upset. The Sun would reach turnoff earlier — that is, it would leave the Main Sequence, the family of stable stars, sooner than otherwise.
According to the Standard Model, photinos should reduce the life of the Sun only by a billion years.
Only?
A billion years was a long time — the Universe itself was only around twenty billion years out of its Big Bang egg — but the Sun would still be left with many billions of years of stable, Main Sequence existence…
According to the Standard Model. But she already knew the Model was wrong, didn’t she?
Lieserl.
“Hmm?”
We have the answer. We think.
“Tell me.”
The Standard Model predicts the photino cloud should be contained within the fusing core, within ten percent of the total Solar diameter. Right? But, according to the best fits we’ve made to your data —
“Go on, Kevan.”
There are actually significant photino densities out to thirty percent of the diameter. Three times as much as the Model; nearly a third of the —
“Lethe.” She looked down. The heart of the Sun still glowed peacefully in interleaved shades of pink and blue. “That must mean the fusion core is swamped with photinos.”
Even through the crude wormhole telemetry link she could hear the distress in his voice. The temperature at the center is way, way down, Lieserl. In fact —
“In fact,” she said quietly, “it’s possible the fusion processes have already been extinguished altogether. Isn’t it, Kevan? Perhaps the core of the Sun has already gone out, like a smothered flame.”
Yes. Lieserl, the most disturbing thing for me is that no one here can come up with a mechanism for such a photino cloud to form naturally…
“What’s the lifecycle prediction? How long has the Sun left to live?”
No hesitation this time. Zero.
At first the blunt word made no sense. “What?”
Zero, on the scales we’re talking about — timescales measured in billions of years. In practice, we’re looking at perhaps one to ten million years left. Lieserl, that’s nothing in cosmic terms.
“I know. But it ties in with the predictions out of Superet, doesn’t it? The data they collected through Michael Poole’s wormhole daisy-chain.”
Yes.
“Kevan, you shouldn’t feel too distressed. Five million years is fifty times the length of human history so far — ”
Maybe. Kevan’s voice took on a harder edge, as if he personally resented the aging of the Sun. But I have kids. I hope to have descendants still alive in five million years. Damn it, I hope to be sentient still myself. Why not? It’s only five megayears; we’re out of the Dark Ages now, Lieserl.