Asimov's SF, September 2010 (21 page)

"What? That's it, just like that, they're married?"

"No, no, no,” he said. “It only means that she accepts the courtship—that she takes him seriously and, when it comes, she will listen to his proposal. Often a woman may have rocks and eggs from many young men. She doesn't have to accept, only take him seriously."

"Oh,” I said.

But it still made no sense. How old was Carlos Fernando, twenty Venus years? What was that, twelve Earth years or so? He was far too young to be proposing.

"No one can terraform Venus,” Carlos Fernando said.

Carlos Fernando had been uninterested in having me join in Leah's discussion, but Leah, oblivious to her host's displeasure (or perhaps simply not caring), had insisted that if he wanted to talk about terraforming, I should be there.

It was one room of Carlos Fernando's extensive palaces, a rounded room, an enormous cavernous space that had numerous alcoves. I'd found them sitting in one of the alcoves, an indentation that was cozy but still open. The ubiquitous female guards were still there, but they were at the distant ends of the room, within command if Carlos Fernando chose to shout, but far enough to give them the illusion of privacy.

The furniture they were sitting on was odd. The chairs seemed sculpted of sapphire smoke, yet were solid to the touch. I picked one up and discovered that it weighed almost nothing at all. “Diamond aerogel,” Carlos Fernando said. “Do you like it?"

"It's amazing,” I said. I had never before seen so much made out of diamond. And yet it made sense here, I thought; with carbon dioxide an inexhaustible resource surrounding the floating cities, it was logical that the floating cities would make as much as they could out of carbon. But still, I didn't know you could make an aerogel of diamond. “How do you make it?"

"A new process we've developed,” Carlos Fernando said. “You don't mind if I don't go into the details. It's actually an adaptation of an old idea, something that was invented back on Earth decades ago, called a molecular still."

When Carlos Fernando mentioned the molecular still, I thought I saw a sharp flicker of attention from Leah. This was a subject she knew something about, I thought. But instead of following up, she went back to his earlier comment on terraforming.

"You keep asking questions about the ecology of Mars,” she said. “Why so many detailed questions about Martian ecopoiesis? You say you're not interested in terraforming, but are you really? You aren't thinking of the old idea of using photosynthetic algae in the atmosphere to reduce the carbon dioxide, are you? Surely you know that that can't work."

"Of course.” Carlos Fernando waved the question away. “Theoretical,” he said. “Nobody could terraform Venus, I know, I know."

His pronouncement would have been more dignified if his voice had finished changing, but as it was, it wavered between squeaking an octave up and then going back down again, ruining the effect. “We simply have too much atmosphere,” he said. “Down at the surface, the pressure is over ninety bars—even if the carbon dioxide of the atmosphere could be converted to oxygen, the surface atmosphere would still be seventy times higher than the Earth's atmospheric pressure."

"I realize that,” Leah said. “We're not actually ignorant, you know. So high a pressure of oxygen would be deadly—you'd burst into flames."

"And the leftover carbon,” he said, smiling. “Hundreds of tons per square meter."

"So what are you thinking?” she asked.

But in response, he only smiled. “Okay, I can't terraform Venus,” he said. “So tell me more about Mars."

I could see that there was something that he was keeping back. Carlos Fernando had some idea that he wasn't telling.

But Leah did not press him, and instead took the invitation to tell him about her studies of the ecology on Mars, as it had been transformed long ago by the vanished engineers of the long-gone Freehold Toynbee colony. The Toynbee's engineers had designed life to thicken the atmosphere of Mars, to increase the greenhouse effect, to melt the frozen oceans of Mars.

"But it's not working,” Leah concluded. “The anaerobic life is being out-competed by the photosynthetic oxygen-producers. It's pulling too much carbon dioxide out of the atmosphere."

"But what about the Gaia effect? Doesn't it compensate?"

"No,” Leah said. “I found no trace of a Lovelock self-aware planet. Either that's a myth, or else the ecology on Mars is just too young to stabilize."

"Of course on Venus, we would have no problem with photosynthesis removing carbon dioxide."

"I thought you weren't interested in terraforming Venus,” I said.

Carlos Fernando waved my objection away. “A hypothetical case, of course,” he said. “A thought exercise.” He turned to Leah. “Tomorrow,” he said, “would you like to go kayaking?"

"Sure,” she said.

Kayaking, on Venus, did not involve water.

Carlos Fernando instructed Leah, and Epiphany helped me.

The “kayak” was a ten-meter long gas envelope, a transparent cylinder of plastic curved into an ogive at both ends, with a tiny bubble at the bottom where the kayaker sat. One end of the kayak held a huge, gossamer-bladed propeller that turned lazily as the kayaker pedaled, while the kayaker rowed with flimsy wings, transparent and iridescent like the wings of a dragonfly.

The wings, I discovered, had complicated linkages; each one could be pulled, twisted, and lifted, allowing each wing to separately beat, rotate, and camber.

"Keep up a steady motion with the propeller,” Epiphany told me. “You'll lose all your maneuverability if you let yourself float to a stop. You can scull with the wings to put on a burst of speed if you need to. Once you're comfortable, use the wings to rise up or swoop down, and to maneuver. You'll have fun."

We were in a launching bay, a balcony protruding from the side of the city. Four of the human-powered dirigibles that they called kayaks were docked against the blister, the bulge of the cockpits neatly inserted into docking rings so that the pilots could enter the dirigible without exposure to the outside atmosphere. Looking out across the cloudscape, I could see dozens of kayaks dancing around the city like transparent squid with stubby wings, playing tag with each other and racing across the sky. So small and transparent compared to the magnificent clouds, they had been invisible until I'd known how to look.

"What about altitude?” I asked.

"You're about neutrally buoyant,” she said. “As long as you have airspeed, you can use the wings to make fine adjustments up or down."

"What happens if I get too low?"

"You can't get too low. The envelope has a reservoir of methanol; as you get lower, the temperature rises and your reservoir releases vapor, so the envelope inflates. If you gain too much altitude, vapor condenses out. So you'll find you're regulated to stay pretty close to the altitude you're set for, which right now is,” she checked a meter, “fifty-two kilometers above local ground level. We're blowing west at a hundred meters per second, so local ground level will change as the terrain below varies; check your meters for altimetry."

Looking downward, nothing was visible at all, only clouds, and below the clouds, an infinity of haze. It felt odd to think of the surface, over fifty kilometers straight down, and even odder to think that the city we were inside was speeding across that invisible landscape at hundreds of kilometers an hour. There was only the laziest feeling of motion, as the city drifted slowly through the ever-changing canyons of clouds.

"Watch out for wind shear,” she said. “It can take you out of sight of the city pretty quickly, if you let it. Ride the conveyor back if you get tired."

"The conveyor?"

"Horizontal-axis vortices. They roll from west to east and east to west. Choose the right altitude, and they'll take you wherever you want to go."

Now that she'd told me, I could see the kayakers surfing the wind shear, rising upward and skimming across the sky on invisible wheels of air.

"Have fun,” she said. She helped me into the gondola, tightened my straps, looked at the gas pressure meter, checked the purge valve on the emergency oxygen supply, and verified that the radio, backup radio, and emergency locator beacons worked.

Across the kayak launch bay, Leah and Carlos Fernando had already pushed off. Carlos was sculling his wings alternatingly with a practiced swishing motion, building up a pendulum-like oscillation from side to side. Even as I watched, his little craft rolled over until for a moment it hesitated, inverted, and then rolled completely around.

"Showing off,” Epiphany said, disdainfully. “You're not supposed to do that. Not that anybody would dare correct him."

She turned back to me. “Ready?” she asked.

"Ready as I'm going to be,” I said. I'd been given a complete safety briefing that explained the backup systems and the backups to the backups, but still, floating in the sky above a fifty-two kilometer drop into the landscape of hell seemed an odd diversion.

"Go!” she said. She checked the seal on the cockpit and then with one hand she released the docking clamp.

Freed from its mooring, the kayak sprang upward into the sky. As I'd been instructed, I banked the kayak away from the city. The roll made me feel suddenly giddy. The kayak skittered, sliding around until it was moving sideways to the air, the nose dipping down so that I was hanging against my straps. Coordinate the turn, I thought, but every slight motion I made with the wings seemed amplified drunkenly, and the kayak wove around erratically.

The radio blinked at me, and Epiphany's voice said, “You're doing great. Give it some airspeed."

I wasn't doing great; I was staring straight down at lemon-tinted haze and spinning slowly around like a falling leaf. Airspeed? I realize that I had entirely forgotten to pedal. I pedaled now, and the nose lifted. The sideways spin damped out, and as I straightened out, the wings bit into the air. “Great,” Epiphany's voice told me. “Keep it steady."

The gas envelope seemed too fragile to hold me, but I was flying now, suspended below a golden sky. It was far too complicated, but I realized that as long as I kept the nose level, I could keep it under control. I was still oscillating slightly—it was difficult to avoid over-controlling—but on the average, I was keeping the nose pointed where I aimed it.

Where were Leah and Carlos Fernando?

I looked around. Each of the kayaks had different markings—mine was marked with gray stripes like a tabby cat—and I tried to spot theirs.

A gaggle of kayaks was flying together, rounding the pylon of the city. As they moved around the pylon they all turned at once, flashing in the sunlight like a startled school of fish.

Suddenly I spotted them, not far above me, close to the looming wall of the city; the royal purple envelope of Carlos Fernando's kayak and the blue and yellow stripes of Leah's. Leah was circling in a steady climb, and Carlos Fernando was darting around her, now coming in fast and bumping envelopes, now darting away and pulling up, hovering for a moment with his nose pointed at the sky, then skewing around and sliding back downward.

Their motions looked like the courtship dance of birds.

The purple kayak banked around and swooped out and away from the city; and an instant later, Leah's blue and yellow kayak banked and followed. They both soared upward, catching a current of air invisible to me. I could see a few of the other fliers surfing on the same updraft. I yawed my nose around to follow them, but made no progress; I was too inexperienced with the kayak to be able to guess the air currents, and the wind differential was blowing me around the city in exactly the opposite of the direction I wanted to go. I pulled out and away from the city, seeking a different wind, and for an instant I caught a glimpse of something in the clouds below me, dark and fast moving.

Then I caught the updraft. I could feel it, the wings caught the air and it felt like an invisible giant's hand picking me up and carrying me—

Then there was a sudden noise, a stuttering and ripping, followed by a sound like a snare drum. My left wing and propeller ripped away, the fragments spraying into the sky. My little craft banked hard to the left. My radio came to life, but I couldn't hear anything as the cabin disintegrated around me. I was falling.

Falling.

For a moment I felt like I was back in zero-g. I clutched uselessly to the remains of the control surfaces, connected by loose cords to fluttering pieces of debris. Pieces of my canopy floated away and were caught by the wind and spun upward and out of sight. The atmosphere rushed in and my eyes started to burn. I made the mistake of taking a breath, and the effect was like getting kicked in the head. Flickering purple dots, the colors of a bruise, closed in from all directions. My vision narrowed to a single bright tunnel. The air was liquid fire in my lungs. I reached around, desperately, trying to remember the emergency instructions before I blacked out, and my hands found the back-up air-mask between my legs. I was still strapped into my seat, although the seat was no longer attached to a vehicle, and I slapped the breathing mask against my face and sucked hard to start the airflow from the emergency oxygen. I was lucky; the oxygen cylinder was still attached to the bottom of the seat, as the seat, with me in it, tumbled through the sky. Through blurred eyes, I could see the city spinning above me. I tried to think of what the emergency procedure could be and what I should do next, but I could only think of what had gone wrong. What had I done? For the life of me I couldn't think of anything that I could have done that would have ripped the craft apart.

The city dwindled to the size of an acorn, and then I fell into the cloud layer and everything disappeared into a pearly white haze. My skin began to itch all over. I squeezed my eyes shut against the acid fog. The temperature was rising. How long would it take to fall fifty kilometers to the surface?

Something enormous and metallic swooped down from above me, and I blacked out.

Minutes or hours or days later I awoke in a dimly lit cubicle. I was lying on the ground and two men wearing masks were spraying me with jets of a foaming white liquid that looked like milk but tasted bitter. My flight suit was in shreds around me.