“I think I can start to see hope in all of this/’ Sargenti said. “Not much, maybe, but some nevertheless.”

“Hope is not always a good thing,” Isak said, his wry grin gone. “Let me tell you something about hope. It’s the murder of peaceful sleep, the birth of endless worry. All things considered, I think we might have been better off hopeless—and coldly rational.”

Sargenti looked at him with dismay; but Isak did not notice as he turned away from her, crumpled a dry twig in his hands, threw it on the fire, and watched it burn.

7

Carbonaceous Chondrite

The IQ boosters worked swiftly, surging up through the arteries in her neck, seeking the outer layers of the neocortex. Manufactured from algae that had been genetically tricked into producing human enzymes, one set of boosters more than tripled the rate at which nerves recharged and fired, while other substances increased the growth of new nerve connections and modulated energy efficiency. It was the increase in firing frequency that had the first and most profound effect. After only two days on the boost, Tam and her crew were connecting disparate and seemingly unrelated facts faster than they had ever before in their entire lives, possibly faster than any human beings since the beginning of time.

One side effect of her newly acquired abilities was that she could now clearly see the flicker of her liquid crystal display pad, which usually cycled too quickly for the human eye to register. Watching the pad (especially in the 3-D mode) became an activity guaranteed to trigger migraine, and she worried that there might be other unanticipated effects. Yet they were all being forced to think faster, to redesign their own brain chemistries, and, whenever necessary, to experiment upon themselves. They had no choice.

They still called her Prime Minister Tam, although she had retired from politics years ago, and since then had been fulfilling her lifelong dream of becoming a space explorer. Sargenti-Peterson, the comet into which she and her team had burrowed, was now moving deep within the orbit of Mercury. Tam’s little world, a marriage of ship and comet, was about the size and shape of Manhattan Island, and from all available evidence the comet was a mere splinter shot from the interior of a much larger body. Some four and a half billion years ago, hydrothermal streams must have honeycombed the parent planetoid. Their remnants were everywhere, in the form of salt veins and microgeodes full of pyrrhotite crystals. As with Ceres, there had been an early period of melting over the entire volume of rock, brought on mostly by the decay of alumi-num-26 and other radioactive elements that had been injected in vast quantities into the solar system—fresh and hot from a supernova—almost at the moment the Sun and planets formed.

About four billion B.C., comet Sargenti-Peterson had become warm and wet inside; but the subsurface springs could not possibly have lasted forever. They were, in those days, losing heat at the rate of a half degree per million years. A half-billion years of warmth, and then it was all over. A long time, but not forever.