A soft male voice spoke in Bisesas ear. Nominal, Hanse, as you can see from my output. Bisesa? Go ahead. Im here to assist you during your extravehicular activity in any way I can. Hanse said, I know the suit design must seem a little odd, Bisesa. Its all about PPP.

PPP?.

Planetary protection protocols. We never bring our suits inside the terrestrial hab modules; we never mix environments. Protecting Mars and Earth life from each other.

Even though they are kissing cousins.

Theyre the worst. And also there is the question of dust. Mars dust is rusty and toxic and full of peroxides, very corrosive. Best to keep it out of the habs, and our lungs. We must keep the suit seals brushed free of dust, in fact, or it becomes harder to make them, and you dont want to be stuck out here. Ill show you how later.

The doctors face came swimming into view behind her own visor. Youre doing good, Bisesa. Try moving around.

Bisesa raised her arms and lowered them; there was a whir of servos, and the suit felt as light as a feather. It feels odd not to be able to lower my arms all the way. Or to be able to scratch my face. Thatll pass, I guess.

I can scratch your face for you if Ill let you know, Suit Five. She looked around. The ground was flat and white, the sky a smoggy dark. The station modules were somber masses looming over her, with equipment and stores heaped up against their stilts, and vehicles parked up: those two rovers with snowplow blades, even what looked like snowmobiles. Discovery was long gone, driving itself back to Lowell.

Alexei, Myra, the whole station crew, everybody at Wells but Paula was here, in their green spacesuits and with illuminated faces, all looking at her. The snow kept falling, big fat flakes, from a lid of gray cloud. Im at the pole of Mars. Good God. She raised her hand and flexed her gloved fingers.

Yuri approached Bisesa. We have a short walk to make. Just a few hundred meters. The drilling rig is positioned away from the habs for safety, and for planetary protection. Just walk normally, and youll be fine. Please. Walk with me. Myra, you too.

Bisesa tried it. One step after another, she walked as easily as she had since she was three years old. The suit was obviously helping her. Yuri walked between Myra and Bisesa. The others went ahead.

Drilling engineer Hanse Critchfield had ROUGHNECK printed on the back of his life support pack, with a cartoon of a gushing oil well. His suit looked heftier than the others. Perhaps it was a super-powered version, designed for the heavy work of the drilling rig.

The Martian snowflakes pattered against Bisesas visor, but sublimated immediately, leaving the faintest of stains.

I can assist you any way you require, by the way, said Suit Five.

Im sure you can.

I am managing your data transfer and your consumables. Also I have sophisticated processing functions. For instance if you are interested in the geology I can process your field of view and highlight exceptions of interest: unusual rock or ice types, unconformities.

I dont think that will be necessary today.

I wish you would explore my physical functions. You may know that under Martian gravity walking is actually more energy-efficient than running. If you like I can stress selected muscle groups as you walk, thus providing an overall workout Oh, shut up, Suit Five, you bore, Yuri snapped. Bisesa, I apologize. Our electronic companions are marvels. But they can get in the way, cant they? Especially when one is surrounded by such wonder.

Myra looked around at the dismal plain of rock-hard ice, the scattered snowflakes falling through the beams of her helmet lights. She said skeptically, Wonder?

Yes, wonderfor a glaciologist anyhow. I just wish I lived in a universe peaceful enough to indulge my passion without distraction.

They approached the largest structure on the ice. It was a hemispherical dome more than twenty meters tall, Bisesa guessed. She could see a ribbed structure under flaccid panels; it was a tent, supported by the ribs, not inflated. Yet it had airlocks of fabric, through which they had to pass in turn.

This was the drilling rig, Hanse Critchfields baby, and he helped Bisesa bend to get through the lock. These are PPP barriers, not really airlocks. In fact we keep a slight negative pressure in here; if we get a leak the air is sucked in, not blown out. We have to protect any deep life we dig out of our boreholeseven from other sorts of life we might find at other layers. And we have to protect it from us, and vice versa. He spoke with a comical mix of what sounded like a Dutch accent with southern United States, maybe Texan. Maybe he had been watching too many old movies.

Inside the dome, the seven of them stood in bright fluorescent light under sagging fabric walls. The derrick, even inert, was an impressive piece of gear, a scaffolding tower set on a massive base of Mars glass. Hanse ran through the mass and power: thirty tonnes, five hundred kilowatts. The coiled drill string was four kilometers long, more than enough to reach the base of the ice cap. A grimy plant stood by to pump a fluid into the borehole, to keep it from collapsing as the ice flowed under its own sheer weight: the drilling teams used liquid carbon dioxide, condensed by this plant from the Martian air.

Hanse began to boast about the technical challenges the drillers had faced: the need for new lubricants, the way moving mechanical parts tended to stick together in the low pressure. Thermal control is the key. We have to take it slow; you dont want too much heat building up down there. For one thing, if the water ice melts, you get water mixing with liquid carbon dioxidepow, the product is carbonic acid, and then you are in trouble. The Aurora crew brought along a toy rig you could load on a trailer, that could only dig down maybe a hundred meters. This baby is the first authentic drilling rig on Mars Yuri cut him off. Enough of the guided tour.

Myra walked to the drill platform. This borehole has no fluid in it. In fact youve sleeved it.

Yuri nodded. This was the first hole we dug, down to it. We knew there was something down there, actually, under the ice, from radar studies. When we reached it we came back out, and put in a request to Lowell for a mass budget to provide us with a sleeve sufficient to keep the borehole open permanently. Then we pumped out the drill fluid Hanse said, And we sent down another bore in parallel. At first we dropped down cameras and other sensors. But then He bent and lifted a hatch. It exposed a hole in the ground maybe two meters across; a platform rested just below its lip, with a small control handle mounted on a stand.

It was obvious what this was. An elevator, Bisesa breathed.

Yuri nodded. Okay. Moment of truth. You and me, Bisesa. Alexei. Ellie. Myra. Hanse, you stand by up here. And you, Grendel. Yuri went and stood on the platform, and looked back, waiting. Bisesa, is that acceptable? I guess this is your show now.

Her breath caught. You want me to ride that thing? Two kilometers down into the ice to this Pit of yours?

Myra held her hand; despite the servos she could barely feel her daughters grasp. You dont have to do this, Mum. They havent even told you what theyve found down there.

Believe me, Alexei said fervently. Its best you see for yourself. Lets get it done, Bisesa said. She strode forward, trying not to betray her fear.

They stood together, facing inward. The round metal platform felt crowded with the five of them aboard, in their spacesuits.

The disk jolted into motion, whirring downward into the ice tunnel, supported by tracks embedded in the walls. Bisesa looked up. It was if she was descending into a deep, brightly lit well. She felt a profound dread of falling, of being trapped.

The suit murmured, I can detect rapid breathing, an elevated pulse. I can compensate for any increase in atmospheric pressure Hush, she whispered. The descent was mercifully short. Yuri said, Brace now The elevator platform jolted to a halt.

There was a metal door, a hatch set in the ice behind Yuri. He turned and hauled it open. It led to a short tunnel, lit brightly by fluorescent tubes. Bisesa glimpsed a flash of silver at the end of the passage.

Yuri stood back. I think you should go first, Bisesa.

She felt her heart thump.

She took a breath and stepped forward. The tunnel floor was rough-cut, not flat, treacherous. She concentrated on walking, not looking ahead, ignoring the silvery glints in the corner of her vision.

She stepped out of the tunnel into a broader chamber, cut crudely into the ice. A quick glance up showed the narrow borehole that had been drilled to get to this point. Then she looked straight ahead, to see what the Spacers had found here, buried under the ice of the Martian north pole.

She saw her own reflection looking back at her. It was the archetypal Firstborn artifact. It was an Eye.

24: CLOSEST APPROACHES.

A distorted image of the Liberator slid across the face of the Q-bomb, all lights blazing. Edna felt a stab of satisfaction. Mankind had come here with intent.

Their first pass at the Q-bomb was unpowered, a scouting run. At closest approach the ship shuddered, once, twice: the launch of two small probes, one injected into low orbit around the Q-bomb, and the other aimed squarely at its surface.

Then the smooth, mirrored landscape receded as the Liberator swept away.

They scrolled through their displays. No harm had come to the ship. The Q-bomb was no more massive than a small asteroidit had the density of leadand the ships trajectory was not deflected significantly by its gravity.

But we learned some things, John reported. Nothing we didnt expect. Its a sphere to well within the tolerances any human manufacturing process could manage. Then theres that usual anomalous geometry.

Pi equals three.

Yes. Our probe went into orbit around it. The bombs mass is so low that its a slow circuit, but the probe ought to stay with it all the way in from now on. And the lander is coming down The ship shuddered, and Edna grabbed her seat. What the hell was that? Libby?

Gravity waves, Edna.

The pulse came from the Q-bomb, John said, tense, almost shouting. The lander. He replayed images of a gray hemisphere bursting from the flank of the Q-bomb, swallowing the lander, and then dissipating. It just ate it up. There was a sort of bubble. If Bill Carel is right, he said heavily, what we just saw was the birth and death of a whole baby cosmos. A universe used as a weapon. He laughed, but without humor. Strewth, what are we dealing with here?

We know what were dealing with, Edna said evenly. Technology, thats all. And so far it hasnt done anything we wouldnt have expected. Hold it together, John.

He snapped, irritable, scared, Im only human, for Christs sake.

Libby, are we ready for pass two?

All systems nominal, Edna. The flight plan calls for an engine fire thirty seconds from now. Do you need a countdown?

Look, just do it, John said tightly. Please check your restraints...

Bisesa walked slowly around the chamber in the ice. It was a rough sphere, and the Eye filled it. She looked up and saw her own distorted reflection, her head grotesque in the spacesuit helmet. She could feel there was something there. A presence, watching. Hello, boys, she murmured. Remember me?

Ellie, Alexei, Yuri, crowding with Myra into the chamber, exchanged excited, nervous glances. This is why we brought you here, Bisesa, Yuri said.

Okay. But what the hell is it doing here? All the Eyes in the solar system disappeared after the sunstorm.

I can answer that, said Ellie. The Eye has evidently been here since before the sunstormlong before. It is radiating high-energy particles in all directionsa radiation with a distinctive signature. Which is why I was brought in. I worked at the lunar alephtron. I am something of an authority on quantum black holes. I was thought a good candidate to study this thing...

It was the first time Ellie had spoken to Bisesa at any length. Her manner was odd; she spoke without eye contact, and with random smiles or frowns, and emphases in the wrong places. She was evidently the kind of individual whose high intelligence was founded on some complex psychological flaw. She reminded Bisesa of Eugene.

The lunar alephtron was mankinds most powerful particle accelerator. Its purpose was to probe the deep structure of matter by hurling particles against each other at speeds approaching that of light. We are able to reach densities of mass and energy exceeding the Planck densitythat is, when quantum mechanical effects overwhelm the fabric of spacetime.

Myra asked, And what happens then?

You make a black hole. A tiny one, more massive than any fundamental particle, but far smaller. It decays away almost immediately, giving off a shower of exotic particles.

Just like the Eyes radiation, Bisesa guessed. So what, Myra asked, have tiny black holes got to do with the Eye? We believe we live in a universe of many spatial dimensionsI mean, more than three, said Ellie.

Other spaces lie next to ours, so to speak, in the higher dimensions, like the pages in a book. More strictly its probably a warped compactification ofnever mind, never mind. These higher dimensions determine our fundamental physical laws, but they have no direct influence on our worldnot through electromagnetism, or nuclear forcessave through gravity.

And thats why we make black holes on the Moon. A black hole is a gravitational artifact, and so it exists in higher dimensions as well as in the world we see. By investigating our black holes we can probe those higher dimensions.

And you believe, Bisesa said, that the Eyes have something to do with these higher dimensions.

It makes sense. The receding surface that doesnt move. The anomalous pi-equals-three geometry. This thing doesnt quite fit into our universe...

Like you, Bisesa thought, a little spitefully.

So maybe its a projection from somewhere else. Like a finger pushing through the surface of a puddle of waterin the universe of the meniscus you see a circle, but in fact its a cross-section of a more complex object in a higher dimension.

Somehow Bisesa knew this was right; somehow she could sense that higher interconnection. An Eye wasnt a terminus, a thing in itself, but an opening that led to something higher.

Myra said, But whats this Eye doing here? I think its trapped, said Ellie.

Once more the ship ran in at the Q-bomb. Deep in her guts antimatter and matter annihilated enthusiastically, and superheated steam roared.

And at closest approach the ship swung around, engine still firing, so that its exhaust washed over the face of the Q-bomb. It was their first overtly hostile act; it would have been enough to kill any humans on that mirrored surface.

The drive cut out, and the ship sailed on unpowered.

No apparent effect, John reported immediately.

Edna glanced at him. Keep checking. But I guess we know the result. So do we use the weapons or not?

The final decision was the crews. A signal to the Trojan base and back would take a round-trip time of forty-five minutes, a signal to Earth even longer.

John shrugged, but he was sweating, edgy. The operational order is clear. Weve had no reaction from the Q-bomb to a non-threatening approach, weve seen the destruction of a friendly probe, weve had no reaction to the exhaust wash. Nobody might get this close again. We have to act.

Libby? Officially the AI was the ships executive officer, and, formally, had a say in the decision. I concur with Mr. Metterness analysis. All right.

Edna extracted a softscreen from her coverall, unrolled it and spread it out over the console before her. It lit up as it interfaced with the Liberators systems, and then flashed red with stern commandments about security. Using a virtual keypad Edna entered her security details, and leaned forward so the screen could scan her retinas and cheek tattoo. The softscreen, satisfied, turned amber.

Ready for the third pass, Libby announced.

Do it.

Thirty seconds later the A-drive lit up again, and the Liberator became a blazing matchstick hurling itself through space. This time the burn was harder, the acceleration the best part of two G. Five seconds from closest approach Edna tapped a button on her command softscreen, giving the weapon its final authorization.

The launch of the fusion bomb caused the craft to shudder once more, as if it were nothing but another harmless probe.

With the weapon gone the Liberator sped away. Edna was pressed back in her chair.

Bisesas imagination failed her. How do you trap a four-dimensional object? In a three-dimensional cage, Ellie said. Watch this. She had a pen clipped to her pressure-suit sleeve. She took this, lifted it toward the face of the Eye, and let go. The pen snapped upward, and stuck to the roof of the chamber. What was that? Myra asked. Magnetism?

Not magnetism. Gravity. If the Eye wasnt in the way, you could walk around on the ceiling. Upside down! There is a gravitational anomaly wrapped around the Eye, obviously an artifact just as much as the Eye is. In fact Ive been able to detect structure in there. Patterns, right at the limit of detectability. The structure of the gravitational field itself may contain information...

Yuri smiled. This stuff can be rather fun to think about. You see, there are ways in which a two-dimensional creature, living in a watery meniscus, could trap that finger poking through. Wrap a thread around it and pull it tight, so it couldnt be withdrawn. This gravitational structure must be analogous.

Tell me what you think happened here, Bisesa said.

We think there were Martians, Yuri said. Long ago, back when our ancestors were just smears of purple slime. We dont know anything about them. But they were noisy enough to attract the attention of the Firstborn.

And the Firstborn struck, Bisesa whispered.

Yes. But the Martians fought back. They managed this. A gravitational trap. And it caught an Eye. Here it has remained ever since. For eons, I guess.

Weve tried to use your insights, Bisesa, Ellie said. What do you mean?

What you reported of Mir, and your journey back from it. You said the Eye functions as a gateway, at least some of the time. Like a wormhole perhaps. So weve experimented. We reflected some of the Eyes own products back into it, using an electromagnet scavenged from a particle accelerator. Like echoing what somebody says to you.

You tried sending a signal through the Eye.

Not just that. Ellie grinned. We got a signal back. A regular pulsing in the decay products. We had it analyzed. Bisesa, it matches the engaged tone from a certain archaic model of cell phone.

My God. My phone, in the temple. You sent a message to my phone, on Mir! Ellie smiled. It was a significant technical success. Myra said, Why not share this with Earth?

Maybe well have to, in the end, Alexei said tiredly. But right now, if they found us, theyd probably just haul the Eye back to the UN Plaza in New York as a trophy, and arrest us. We need a more imaginative response.