Lyla said, You ought to take a look at the view. See what the station is all about. Its much harder to see from within the decks. Elevator. Show us Polyphemus.

Myra looked out through the hull. She saw stars whirling slowly, the universe become a pinwheel. And an oval of gold lit up on the window and began to track upward, slowly, countering the rotation to pick out a corner of the star field. There Myra made out a faint disc, misty-gray and with rainbows washing across its face. A smaller station hung behind it, a knot of instruments.

That, Lyla said, is a telescope. One big, spinning, fragile Fresnel lens. Nearly a hundred meters across.

Myra asked, Wasnt the sunstorm shield a Fresnel lens?

It was...

So this was yet another technological descendant of the tremendous shield that had once sheltered the Earth.

Lyla said, They call that fellow Polyphemus, the Cyclops, after the most famous of the one-eyed giants of the myths. Galatea was actually the name of the Nereid he loved, according to some versions of the stories. Polyphemus is the oldest but still the most impressive instrument they have here.

Yuri, an instrument man himself, was fascinated, and peppered Lyla and Alexei with questions.

Big mirrors were on the face of it easier to manufacture than big lenses, but it turned out that a lens was the preferred technology for building really huge telescopes because of its better optical tolerance; the longer pathways traversed by light rays gathered up by a mirror tended to amplify distortions rather than to diminish them, as a lens would. A Fresnel lens was a compromise design, a composite of many smaller lenses fixed into a lacy framework and spun up for stability. Lyla said the sub-lenses at the rim of the structure were thin enough to roll up like paper. There were technical issues with Fresnel lenses, the main one being chromatic aberration they were narrow-bandwidth devices. But there was an array of corrective opticsSchupmann devices, Lyla saidinstalled before the main lens itself to compensate for this.

The lens itself is smart, she said. It can correct for thermal distortions, gravitational tweaks...With this one big beast alone you can detect the planets of nearby stars, and study them spectroscopically, and so on. And now they are working on an interferometer array. More mirrors, suspended in space. Elevator, show us...

More tracking ovals lit up on the wall.

Theyre called Arges, Brontes, and Steropes. More Cyclops giants. Working together they are like a composite telescope of tremendous size.

Its no coincidence that she came here. Athena, I mean. Her transmission back home was picked up by Polyphemus. Very faint laser light. Elevator, resume.

The elevator plunged without slowing through the first of the decks. Myra glimpsed a floor that curved upwards, a dcor of silver-gray and pink, and people who walked with slow bounds. The Moon deck, she said.

Right, Lyla said. You understand that Galatea is centrifugally stratified. Well be stopping on the Mars deck, where youll be meeting Athena.

As Myra absorbed that, Yuri nodded. It will help if we can stay in condition in the G conditions were used to.

Yeah, said Lyla. Not many go further than that. Nobody but our ambassadors from Earth, in fact.

Ambassadors? Myra asked.

Actually cops. Astropol. She pulled a face. We encourage them to stay down there, in their own lead-boot gravity field. Keeps them from getting in the way of the real work.

They dont know were here, do they? No reason why they should, Alexei said. Myra guessed, And they dont know about Athena.

No, they dont, Lyla said. At least I dont think they do. They really are just cops; they should have sent up a few astronomers.

I dont understand any of this, Myra confessed. Where Athena has been. How she came back. And I dont understand why Im here.

All your questions will be answered soon, Myra, a voice spoke from the air.

It was the second time Athena had spoken to Myra. The others looked at her curiously, even a little enviously.

43: CHICAGO.

Emeline, Bisesa, and Abdi traveled the last few kilometers to Chicago in a western-movie-style covered wagon. It was drawn by muscular, hairy ponies, a round-bodied native stock that turned out to be particularly suited to working in the deep cold. The road followed the line of a pre-Freeze rail track, but Emeline said it wasnt practical to run trains this far north, because of ice on the rails and frozen points.

By now Bisesa was wrapped up like an Inuit, with layers of wool and fur over her thin Babylonian clothes, and her phone lost somewhere deep underneath. Emeline told her that the russet-brown wool came from mammoths. Bisesa wasnt sure if she believed that, for surely it would be easier to shear a sheep than a mammoth. It looked convincing, however.

Despite the furs, the cold dug into her exposed cheeks like bony fingers. Her eyes streamed, and she could feel the tears crackling to frost. Her feet felt vulnerable despite the heavy fur boots she wore, and, fearing frostbite, she dug her gloved hands into her armpits. Its like Mars, she told her companions.

Abdi grimaced, shivering. Are you sorry you came? Im sorry I dont still have my spacesuit. The phone, tucked warmly against her belly, murmured something, but she couldnt hear.

Chicago was a black city lost in a white landscape.

The disused rail track ran right into Union Station. It was a short walk from the station to Emelines apartment. In the streets, huge bonfires burned, stacked up under dead gas-lamps and laboriously fed with broken-up lumber by squads of men, bundled up, their heads swathed in helmets of breath-steam. The fires poured plumes of smoke into the air, which hung over the city like a black lid, and the faces of the buildings were coated with soot. The people were all bundled up in fur so they looked almost spherical as they scurried from the island of warmth cast by one bonfire to the next.

There was some traffic on the roads, horse-drawn carts, even a few people cyclingnot a single car anywhere in this version of 1920s Chicago, Bisesa reminded herself. Horse manure stood everywhere, frozen hard on the broken tarmac.

It was extraordinary, a chill carcass of a city. But it was somehow functioning. There was a church with open doors and candlelit interior, a few shops with open for business signsand even a kid selling newspapers, flimsy single sheets bearing the proud banner Chicago Tribune.

As they walked, Bisesa glimpsed Lake Michigan, to the east. It was a sheet of ice, brilliant white, dead flat as far as the eye could see. Only at the shore was the ice broken up, with narrow leads of black open water, and near the outlet of the Chicago river men labored to keep the drinking-water inlet pipes clear of ice, as they had been forced to since the very first days after the Freeze.

People moved around on the lake. They were fishing at holes cut into the ice, and fires burned, the smoke rising in thin threads. Somehow the folk out there looked as if they had nothing to do with this huge wreck of a city at all.

Emeline said, panting as they walked, The citys not what it was. Weve had to abandon a lot of the suburbs. The working towns kind of boiled down to an area centered on the Loopmaybe a half-mile to a mile in each direction. The populations shrunk a lot, what with the famine and the plagues and the walkaways, and now the relocation to New Chicago. But we still use the suburbs as mines, I suppose you would say. We send out parties to retrieve anything we can find, clothes and furniture and other stores, and wood for the fires and the furnaces. Of course weve had no fresh supplies of coal or oil since the Freeze.

It turned out providing lumber was Emelines job. She worked in a small department attached to the Mayors office responsible for seeking out fresh sources of wood, and organizing the transport chains that kept it flowing into the habitable areas of the city.

A city like this isnt meant to survive in such conditions, Abdi said. It can endure only by eating itself, as a starving body will ultimately consume its own organs.

We do what we must, Emeline said sharply.

The phone murmured, Ruddy visited Chicago onceon Earth, after the date of the Discontinuity. He called it a real city. But he said he never wanted to see it again.

Hush, Bisesa said.

Emelines apartment turned out to be a converted office on the second floor of a skyscraper called the Montauk. The building looked skinny and shabby to Bisesa, but she supposed it had been a wonder of the world in the 1890s.

The apartments rooms were like nests, the walls and floors and ceilings thick with blankets and furs. Improvised chimney stacks had been punched in the walls to let the smoke out, but even so the surfaces were covered with soot. But there was some gentility. In the living room and parlor stood upright chairs and small tables, delicate pieces of furniture, clearly worn but lovingly maintained.

Emeline served them tea. It was made from Indian leaves from carefully hoarded thirty-year-old stock. By such small preservations these Chicagoans were maintaining their identity, Bisesa supposed.

They hadnt been back long when one of Emelines two sons showed up. Aged around twenty he was the younger by a year, called Joshua after his father. He came in carrying a string of fish; breathing hard, red-faced, he had been out on Lake Michigan. Once he had peeled out of his furs he turned out to be a tall young man, taller than his father had ever been. And yet he had something of Joshs openness of expression, Bisesa thought, his curiosity and eagerness. He seemed healthy, if lean. His right cheek was marked by a discolored patch that might have been a frostbite scar, and his face glistened with an oil that turned out to be an extract of seal blubber.

Emeline took the fish away to skin and gut. She returned with another cup of tea for Joshua. He politely took the cup, and swigged the hot tea down in one gulp.

My father told me about you, Miss Dutt, Joshua said uncertainly to Bisesa. All that business in India.

We came from different worlds.

My father said you were from the future.

Well, so I am. His future, anyhow. Abdikadirs father came through with me too. We were from the year 2037, around a hundred and fifty years after your fathers time slice.

His expression was polite, glazed.

I suppose its all a bit remote to you.

He shrugged. It just doesnt make any difference. All that history isnt going to happen now, is it? We wont have to fight in your world wars, and so on. This is the world weve got, and were stuck with it. But thats fine by me.

Emeline pursed her lips. Joshua rather enjoys life, Bisesa.

It turned out he worked as an engineer on the rail lines out of New Chicago. But his passion was ice-fishing, and whenever he got time off he came back up to the old city to get into his furs and head straight out on the ice.

He even writes poems about it, Emeline said. The fishing, I mean.

The young man colored. Mother He inherited that from his father, at least. A gift for words. But of course were always short of paper.

Bisesa asked, What about his brotheryour older son, Emeline? Where is he?

Her face closed up. Harry went walkaway a couple of years back. This was clearly distressing to her; she hadnt mentioned it before. He said hed call back, but of course he hasntthey never do.

Joshua said, Well, he thinks hes going to be put under arrest if he comes back.

Mayor Rice declared an amnesty a year ago. If only hed get in touch, if only hed come back just for a day, I could tell him he has nothing to fear.

They spoke of this a little, and Bisesa began to understand. Walkaway: some of Chicagos young people, born on Mir and seduced by the extraordinary landscape in which they found themselves, had chosen to abandon their parents heroic struggle to save Chicago, and the even more audacious attempt to build a new city south of the ice. They simply walked off, disappearing into the white, or the green of the grasslands to the south.

Its said they live like Eskimos, said Joshua. Or maybe like Red Indians.

Some of them even took reference books from the libraries, and artifacts from the museums, so they could work out how to live, Emeline said bitterly. No doubt many of these young fools are dead by now.

It was clear this was a sore point between mother and son; perhaps Joshua dreamed of emulating his older brother.

Emeline cut the conversation short by standing to announce she was off to the kitchen to prepare lunch: they would be served Joshuas fish, cleaned and gutted, with corn and green vegetables imported from New Chicago. Joshua took his leave, going off to wash and change.

When they had gone, Abdi eyed Bisesa. There are tensions here.

Yes. A generation gap.

But the parents do have a point, dont they? Abdi said. The alternative to civilization here is the Stone Age. These walkaways, if they survive, will be illiterate within two generations. And after that their only sense of history will be an oral tradition. They will forget their kind ever came from Earth, and if they remember the Discontinuity at all, it will become an event of myth, like the Flood. And when the cosmic expansion threatens the fabric of the world They wont even understand whats destroying them. But, she thought wistfully, maybe it would be better that way. At least these walkaways and their children might enjoy a few generations of harmony with the world, instead of an endless battle with it. Dont you have the same kinds of conflict at home?

Abdi paused. Alexander is building a world empire. You can think thats smart or crazy, but youve got to admit its something new. Its hard not to be swept up. I dont think we have too many walkaways. Not that Alexander would allow it if we did, he added.

To Bisesas astonishment a telephone rang, somewhere in the apartment. It was an old-fashioned, intermittent, very uncertain ring, and it was muffled by the padding on the walls. But it was ringing. Telephones and newspapers: the Chicagoans really had kept their city functioning. She heard Emeline pick up, and speak softly.

Emeline came back into the lounge. Say, its good news. Mayor Rice wants to meet you. Hes been expecting you; I wrote him from New Chicago. And hell have an astronomer with him, she said grandly.

Thats good, Bisesa said uncertainly. Hell see us this evening. That gives us time to shop. Shop? Are you kidding? Emeline bustled out. Lunch will be a half-hour. Help yourself to more tea.

44: ATHENA.

The Mars deck was like a corridor that rose gradually in either direction, so that as you walked there was the odd sense that you were always at the low point of a dip, never climbing out of it. The gravity was the easy one-third G Myra had got used to on Mars itself. The dcor was Martian red-ocher, the plastic surfaces of the walls, the bits of carpet on the floor. There were even tubs of what looked like red Martian dirt with the vivid green of terrestrial plants, mostly cacti, growing incongruously out of them.

It was hard to believe she was in space, that if she kept on walking she would loop the loop and end up back in this spot.

Alexei was watching her reaction. Its typical Earth-born architecture, he said. Like the bio domes on Mars with the rainstorms and the zoos. They dont see that you dont need all this, that it just gets in the way...

Certainly it all seemed a bit sanitized to Myra, like an airport terminal.

Lyla led the three of them to an office just off the main corridor. It was nothing unusual, with a conference table, the usual softscreen facilities, a stand of coffee percolators and water jugs.

And here Athena spoke to them.

I suppose youre wondering why Ive asked you here today.

Nobody laughed. Yuri dumped the bags in the corner of the conference room, and they helped themselves to coffee.

Myra sat down and looked up into the empty air challengingly. My mother always did say you had a reputation as a comedian.

Ah, said Athena. Aristotle called me skittish. I never had the chance to speak to Bisesa Dutt. Her voice was steady, controlled. But I spoke to many of those who knew her. She is a remarkable woman.

Myra said, She always said she was an ordinary woman to whom remarkable things kept happening.

But others might have crumbled in the face of her extraordinary experiences. Bisesa continues to do her duty, as she sees it.

You speak of her in the present tense. I dont know if shes dead or alive. I dont know where she is.

But you suspect, dont you, Myra? I dont understand how Im talking to you. Why are you here? Watch, Athena said gently. The lights in the room dimmed a little, and a holographic image coalesced on the tabletop before them.

Ugly, bristling, it looked like some creature of the deep sea. In fact it was a denizen of space. It was called the Extirpator.

The day before the sunstorm, Athena had woken to find herself ten million kilometers from Earth. Aristotle and Thales, mankinds other great electronic minds, were with her. They had been downloaded into the memory of a bomb.

The three of them huddled together, in an abstract electronic manner. And then When the images from Procyon died, they all needed a break.

They went out onto the Mars deck. Myra sipped a cola. While Yuri swung improvised pendulums to study the varying artificial gravity, Alexei and Lyla explored it. If you sat down, you were heavier than when you stood up. If you threw a ball any distance, it would be deflected sideways by the spin. And if you ran against the spin, you grew lighter. Laughing, they raced each other along the corridor in big Moonwalk bounds.

Watching them play, Myra was reminded just how young these Spacers all really were.

All of them were reluctant to go back and face Athena again, and talk about what she had discovered on a planet eleven light-years away.

So those swimmers bred themselves to extinction, Alexei said. Sol, what a thing to do.

Yuri said, Better that than let the Firstborn win.

It took us two years to find a way to beam me back home, Athena said softly. We didnt want to broadcast our existence to a dangerous universe. So we put together an optical laserquite powerful, but a tight beam. And when the time came, with my data stream encoded into it, we fired it off at Earth. We anticipated that it would be picked up by Cyclops, which was at the planning stage before the sunstorm.

It was risky, Myra said. If Cyclops hadnt been built after all We had no choice but to make the gamble. Yuri asked, Why you, of the three? Athena paused. We drew lots, after a fashion.