"Incredible, inexplicable," Sundaram said. "Communication, a common language, established this swiftly and surely — when we and the Holont have nothing in common."

He had invented that name for the quantum intelligence. Zeyd, who felt uncomfortable with the idea of mutable avatars — yes, God could do all things, but this raised difficult questions about the soul — suggested, "The great flowerings of civilization on Earth came about when different cultures met, didn't they? Maybe it is like that with us and the holonts."

"Do not forget Simon," Yu said.

Mokoena's eyes shone. "A galactic flowering —"

"Thousands of years hence, millions, if ever," Dayan said. "What we need to know here is how the process goes so fast. Let's concentrate again on asking about physics."

The answer emerged in the course of daycycles, not through dialogue but through demonstration. When Dayan fully grasped its nature and explained to her teammates, the fine hairs stood up on her arms.

"Telepathy would have been spooky enough. This goes far beyond. The Holont knew we were coming and what we would try. It told itself  —  they told themselves — by a message that went back through time."

"No, that cannot be!" Yu disputed, shocked. "It would violate every principle of logic and, yes, science. The conservation laws —"

Dayan shook her head. "When I began to suspect, I consulted our database." As if defensively, her tone went into lecture mode. "The history's lain forgotten because the whole thing was, in fact, deemed impossible. As prestigious a thinker as Hawking insisted nature must rule time travel out somehow, or the paradoxes would run wild. However, there are actually no paradoxes, provided self-consistency obtains. You cannot go back into the past and change what has happened, no matter what you do. But your actions can be a part of what did happen.

"Several of Hawking's contemporaries, Kerr, Thorne, Tipler, described several kinds of time machine, each perfectly in accord with general relativity. But they all required structures that looked physically impossible  —  for instance, a torus with the mass of a giant star, rotating near the speed of light, with more electric charge than the interstellar medium would allow and a magnetic field stronger than anything in nature could generate. Or a cylinder of material denser than any nuclear particle, also spinning close to light speed and infinitely long. Or  —  Well, the theoretical possibility seemed to be a cosmic joke on us, a bauble forever dangling just out of reach."

"And now . . . conditions at the black hole," Sundaram breathed.

Dayan nodded. "Yes. Not that even that allows any of what I mentioned. As nearly as I can tell, the holonts can't personally travel backward through time." Low, not quite evenly: "As nearly as I can tell."

She drew breath. "What they can do is something suggested back in Hawking's era by Forward. They can operate on that sea of particles and energy they exist in. They can form gigantic nuclei, atomic weights vastly greater than anything we've ever achieved, and keep them stable. Electromagnetic forces deform such a nucleus and set it spinning  —  speed, density, field strengths as required. I'm not sure yet whether what they get corresponds to the Kerr smoke ring or a short, wasp-waisted Tipler cylinder, or maybe something else. Anyhow, it causes a warp in space-time, a tiny 'hole' through which particles of sufficiently small wavelength can pass. That means highly energetic gamma-ray photons. Well, photons can be modulated, and modulation can convey information, and if you can send a message, in principle you can do anything.

"The holonts know how to communicate with us because the holonts in the future have already done it. They sent the knowledge back."

Yu looked at a bulkhead as if to see through it, out to star-strewn immensity. "That brings home to us how little we know, how little we are, does it not?" she whispered.

Dayan's voice clanged. "I would say we need to keep a sense of proportion and not get above ourselves, but we'd do wrong to feel humble. The holonts want discourse with us. I don't think that's purely from curiosity. I think that, somehow, we're important to more than ourselves."

At Hansen's call, his cabin door opened and Yu came in. He rose from his desk. Her glance flitted briefly about. She had not been here for weeks; hardly anyone had but him. The room was again neat, almost compulsively so. Kilbirnie had tended to get things into mild disarray. Her image filled a screen, not animated, a single instant of her smile. A few pet objects of hers stood on table and shelf. Air still bore the coolness and heathery tang she liked. But the background music was Baroque, and his attention had been on a sculpture. He stood as erect, immaculately clad, and reserved as always.

"Sit down, Wenji," he invited. "What can I do for you?"

They took chairs. She went straight to the painful point. "I thought you would rather I gave you this news in private."

He raised his brows. "Yes?"

"I have reviewed the plans you and Emil have worked out for that crewed, probe-controlling capsule."

He attempted humor. "We didn't ask you to review anything else." Tautly: "Have you found a mistake? We thought we were ready to start the robots on construction."

She sighed. "You can if you wish. You have run a perfectly good design program. But it didn't take account of some factors, such as cramped work space. I find that to build this thing to those specifications will take weeks."

"Oh." He sat motionless.

"My impression is that you two want it as soon as can be."

"Yes. Not that the astrophysics itself can't wait. Emil, though, Emil is so happy again, now that en will have something real to do. And it seems to have helped the morale of the other Tahirians also."

"And you yourself —" She chopped the sentence off. "The basic problem here is that a vessel suitable for beings of the two races — safe, adequately life-supported, controls and communicators easy to use — it becomes elaborate. That includes being rather large. If it were meant for just a human or a Tahirian, it would be much, much simpler."

He stared at her out of a face become a mask. "Are you certain?" And then: "My apologies. Of course you are."

"I have run a modification of your program," Yu said. "A vessel for one person of a single species could be ready in ten daycycles or less."

Nansen was silent about half a minute.

"Very well," he replied. "Let it be for Emil."

Her careful impersonality dissolved. "Do you truly mean that, Rico? This must be a bitter disappointment."

"Delay would be worse for en ... and, as I told you, even ens fellows. The situation has been approaching horror for those poor Tahirians. If Emil can go piloting, and share ens pleasure in the special Tahirian ways, it should change their feelings for the better. And they are also crew."

"You, though. What of you?"

He shrugged. "I'll find other ways to keep busy. . . . No!" he snapped. "No whining. This is a ship meant for humans. Any who can't make a reasonable life aboard her is a sorry canijo."

Yu refrained from mention of those who were gone. Seeking a diversion, she turned her gaze on the half-completed clay figurine. It was a bust, not in his former representational manner. The head was misshapen in some purposeful fashion, the visage and its expression still more.

"Your hobby," she murmured. "But this is unlike anything else I have seen from you."

"Tahirian influence," he said. "I thought, I suppose like everybody, that every school and style was exhausted long ago and there's nothing to do but make variations on them. Tahirian art gave me new ideas. Perhaps the black hole and the fact of the holonts has, too. At any rate, a pastime."

"You are not doing this just for amusement," she said. "It is too grim. Terrifying, in a way. I don't know why, and that is part of the terror."

"Well," he said roughly, "I don't doubt your analysis of the engineering matter is correct, but I would like to go over it with Emil, as well as your new design. Will you download them for us?"

"Of course." Her undertone continued: "Yes, what we bring back may revitalize art on Earth, together with science, technology, philosophy, everything."

He yielded enough to what was in him that he muttered, "Assuming we get back."

"I expect we will, given your leadership," Yu replied, "but what we will find, I think not even the Holont knows."

Trouble crept likewise over Zeyd. Once he had prepared an explication of his science, transmission of its details was work for a computer. Unlike Mokoena, he could contribute little to the ongoing examination of fundamental questions — the nature of life and its evolution, whatever the form it took. Bit by bit, daycycle by daycycle, it was borne in on him that now he did best to keep out from underfoot. The efforts of his friends to tell him otherwise only made it worse.

He pursued such outside interests as he found. Among them, he took up fencing after he and Nansen improvised outfits. He grew more observant in his faith, reread the Qur'an, pondered new interpretations of it for the universe unfolding before him. Mostly he maintained a cheerful demeanor and was quick with a quip.

But Mokoena knew.

"I shouldn't say this yet," she told him. "I will, however, if you will keep it confidential for a while."

They were in her cabin, late one evenwatch. She had dimmed illumination to the level of candlelight and made it rosy. A screen showed poplars shivering and shimmering in a double row, at the end of which a dome and a minaret stood above white walls. Ventilation blew with the same soughing warmth. He looked up from the chair in which he slumped. "Why the secrecy?" he asked.

She stood above him, dark, full-figured, lightly clad, her eagerness more heartening than any spoken sympathy could have been.

"Announcement would be premature," she said. "Unscientific. Leaping to a conclusion we may never actually be sure we have reached. And still, I can't hold it in any longer. I have to share it. Who better than with you, darling?"

He sat straighter. "Yes?"

"We — we're learning more about the holonts. What they are, how they can possibly be. Not just patterns, mathematical abstractions. What embodies them? How can it be stable?"

She rejoiced to see and hear the awakening in him. "After all our puzzlings about that, is Hanny getting a definite answer?"

"We are, together." She stroked his cheek. "That includes you. Your data showed the holonts how our life works. Then they could draw conclusions about it." She paused, like an athlete readying for a sprint. "It is too soon. This interpretation may be wrong. But it does seem  —  Selim, it does seem the configurations are not transitory. They have a certain permanence. And life like ours, it's pattern and process, too. Does it impose its own trace on the vacuum? Some direction on the randomness, some change in the metric? Do these last? Selim, maybe the holonts — maybe the Holont thinks they do!"

He could not stay seated beneath that mood; he rose to meet it. "What does this imply?"

"Don't you see? That death isn't the end. That. . . something lives on afterward."

"I have always believed that." Wryness: "I am supposed to."

"Here, scientific proof — what that could mean to ... to everybody!"

He kept himself judicious. "Fascinating. I certainly want to know more. But your inference strikes me as a non sequitur. I think the soul, God, the purpose and meaning of existence, will always be matters of faith."

"We'll see," said defiant enthusiasm.

The crew sat in their common room, in the half-ring of council. Nansen was at the center. Dayan stood before them. At her side, Mokoena with a parleur translated for the Tahirians who waited at the edge. Stars gleamed through night in the viewscreens, Milky Way, nebulae, sister galaxies.

"What we are learning — and learning to wonder about — is marvelous and magnificent and overwhelming," Dayan said into the hush. "A hundred years would not teach us everything. A thousand years might not. But, with all respect for the biology and astrophysics and whatever else, this newest finding is too important to wait for a regular report.

"I want to emphasize that it is a finding, neither a possibility nor a speculation but a fact. The Holont appears to have made a special effort to explain it to us. I have gone through the mathematics repeatedly, with computer aid, and verified the theorem. I have a feeling that this is what the Holont has really been working toward — because it has had word from the future about what this can mean to the future."

She heard the susurrus of human and nonhuman breath.

"The Tahirian physicists were wrong," she told them. "I don't say they lied. Doubtless they were quick to believe what they wanted to believe, a reason to end starfaring. It doesn't matter. The truth is, a zero-zero transition is no threat.

"It has zero probability of upsetting the cosmic equilibrium. Or less than zero. You see, the energy transfer actually makes a bond, like the transfers of virtual particles that create the forces holding atoms together. Yes, the effect is quantum-small. But it is finite, it is real. Every voyage brings the universe that much further from the metastable state, toward true stability that can last forever."

Mokoena's fingers flickered. Tahirian manes trembled. From Emil wafted a scent like wind off the sea.

Nansen stood up. His look passed over each of them before he said, quite calmly, "Now we must go home."