The Year's Best Science Fiction: Fifteenth Annual Collection

by Gardner Dozois

  We are three hundred meters down: a football field on end. The descent is easy, simple, routine. You ease rope out under friction, take a pair of steps down, and ease out some more. This descent is demanding and terrifying. You dare not lose concentration. Pitons can pull out, crampons can slip, and you will be just as dead from a fall of a kilometer in Mercury's gravity as Earth's. Yes, it will take a few seconds longer and an academic might note that you hit with less velocity-only about five times instead of fifteen times what is needed to smash your helmet and the skull within it.

  You dare not cause problems for everyone else. One foot after another.

  A person in fear of his or her life needs no more excitement-but if you want it, you glance at the wall in front of you, at layers of ice laid down when dinosaurs were young. This is not on a screen, not a simulation, but never-seen-before reality that puts ice hard in front of your own eyes.

  "Ed," I ask, "do you wonder if anyone might have been here a billion years ago?"

  "Eh? Interesting thought, that. The feature would attract someone with enough curiosity to build spaceships, I should think. But the crack itself wouldn't be that old, now, would it?"

  "No, I guess not." When the layers were laid down, of course, this had been a part of the plain.

  Still, my eyes scan every layer, hoping.

  "Has everyone got positive pressure in their suits?" Dr. Lotati asks, and receives chuckles. "There is," he continues, "a significant build-up of nitrogen gas, and a bare trace of nitrogen tri-flouride, which I would not recommend breathing."

  I call up a temp display and find that it is cold in the crack-about eighty kelvins, versus a hundred twenty at the surface. As I think about it, I notice traces of frost on the outside of my gloves: our insulation is that good. I have no idea what the biological implications of nitrogen tri-fluoride are, but I would rather someone else perform the experiments. A drop rolls down my face plate.

  "Watch your footing, Juanita," Dr. Lotati says. "It's slippery here."

  So far, my crampons dig into the dirty clathrate walls with case, but I can tell it is wet. The wall is mostly ice, but ice that is heavily mixed with crater ejects, pocked with more volatile ices, and stiffened far harder than anything on Earth by cryogenic temperatures. Dr. Lotati says it's something like sandstone, but if it weren't for the gas in the ice, it would be like concrete. There are few cracks, but the piton gun works well, as does the ax.

  "Nitrogen trifluoride data," I ask. Floating in the wall, by virtue of my helmet display hardware, are glowing numbers telling me that nitrogen tri-fluoride is liquid over a range of about 80 kelvins-from about 77 up to 145-which is over 120 Celsius degrees below the freezing point of water. Somehow, stating such temperatures in kelvins above absolute zero is less scary than using negative Celsius degrees below freezing. The vapor pressure of this big, heavy molecule is almost nil at the low end of this temperature range-a wet vacuum.

  A hundred meters to go, and I can see the bridge clearly in the shifting pools of our helmet lights.

  "A sliver of wall appears to have detached itself and slid down until it jammed," Dr. Tierzo tells us. "The top is a jumble with, here and there, flat spaces that may have been part of the original surface, including part of a crater. I wonder if that's what knocked it down?"

  "Hello down there," Karen Svenson calls. "Yes, that crater would explain what looks like a ray network around where you went down. Now that I know what I'm looking at, this spiderweb network of cracks is a real giveaway."

  I hadn't remembered any cracks. I ask my suit to play back my recording of our approach to the side. The surface in the depression was smooth. My pulse races. "Playback two hours ago," I command. In a ghostly video window, my suit shows me almost falling in to the crevasse, but ... "Hey, everyone!" I shout. "Those cracks weren't there before. Dr. Lotati, I've got it on channel six."

  There is a moment of silence.

  "Quickly now," Dr. Lotati speaks briefly and very businesslike. "Those of you still on the wall come down as quickly as possible without panic and without yanking on anything. Mike and Karen, set another belay well back of the cracked area.

  I have my full attention on climbing down, gingerly as possible. Dr. Tierzo is off belay just below me. I remember to lock my crampon spikes out-the bridge is slippery.

  Meanwhile, Dr. Lotati has set an ice bolt in at the far end of our bridge. Dr. Tierzo sets another one in the biggest hunk of bridge she can find at our end and pulls the line tight.

  Then I am off the wall. I quickly clip my line to the bridge line and release myself from the wall ropes. "Off belay."

  Miranda Lotati and the grad student, Eloni, are still on the wall.

  I hear, I think, at very low frequency, a kind of groan.

  "We have the protection in," Karen says. "The cracks are larger!"

  "Wojciech can get your line, Ed," Dr. Lotati says, "release from the wall immediately!"

  "No worry. Here." He tosses me the end of his spare line and I hit it with the loop of a smart 'biner, which opens, takes the line, and shuts faster than I can see-like that old magic trick with hoops. I take up the slack.

  Ed releases and scrambles off the wall, holding the taut line for balance until he reaches me. We move further down the bridge.

  "Come on, Eloni," Ed says encouragingly. The young Kenyan woman is the least experienced of our group-she descends slowly, but flawlessly, a few meters right of where Ed came down. "Toss me the end of your spare line."

  She stops to find it. Miranda Lotati's feet are but a few meters above her. I hear another groan.

  "Come on... Ed says again.

  Finally, Eloni tosses a coiled line toward Ed. It jerks short and dangles below her, a hopeless tangle.

  "Sorry, I try to do this too fast."

  "That's OK, mate," Ed says. "Just come on down now. We'll improvise.

  We feel a slight tremor. She freezes.

  "Down, Eloni. Fast," Randi says.

  Eloni starts moving again. I can see her tremble.

  "Ice!" Karen abouts. Our radios level amplitude, magnifying whispers and buffering shouts-that shout was well buffered.

  Eloni freezes. "Go," Randi snaps, and clips Eloni's helmet with the side of her boot. "Get going!"

  Galvanized, Eloni half scrambles and half falls the remaining fifty meters, landing on her seat where the bridge butts against the wall. She starts fumbling with the 'biner holding her line to the wall belay line. Ed, clipped to a line, moves to help her-I think he has a knife in his hand. Heedless, I follow him using crampons and ax. Ed reaches Eloni.

  I look up and see the sky falling.

  Randi releases and leaps from almost twenty meters up on the wall, unbelayed, right at me. "Catch," she shouts.

  I have time to set my crampon spikes and open my arms. She hits hard, and various pieces of her gear dig into my chest. I grab her as the boots tear free and we skitter together down the side of the bridge. My line stops us after a three-meter slide.

  Ten meters from us, with a roar clearly conducted through the ice we lie against, an avalanche of clathrate pours down. There is no sign of Ed and Eloni.

  Randi clips a line to my belt, rolls off, and starts to scramble back to the top of the bridge, ice dust streaming around her.

  "Ed!" she shouts. "Eloni!"

  The fall increases, becoming a white wall. Randi scrambles into it. I follow and am enveloped in a stream of pulverized clathrate, and I can see nothing. It flows over me, not like sand or water, but something in between, not dense, but still exerting pressure.

  I wait. My helmet is filled with the sound of my breathing.

  "Ed!" Randi abouts again.

  "We're alive." Ed's voice is hoarse and strained. "Trapped next to the wall. The fall created a bit of a pocket. No injuries, but it's getting somewhat cold."

  In spacesuits with rebreathers and plenty of energy, we are in no danger of suffocating. But under our coveralls we wear skintight vacuum suits that depend on a su
rrounding vacuum for much of their thermal control and the fabric of the vacuum suits, while smart and extremely tough, is necessarily thin. Conduction of heat could quickly freeze Ed and Eloni. But, clinging to the side of the bridge with the landslide still in progress, there is nothing I can do to reach them.

  "Got you on locator. Can move." That is Randi Lotati, for me. Move? How?

  I roll over prone to the face of the bridge, reach forward into the flow with my hands, and find purchase. With both arms and legs, I find I can edge forward, too.

  "Solid piece-here," Randi says. "Ice boulder. Think you're on other side."

  "S-sounds that w-way," Ed replies.

  "Line charge. My side. Push like hell when I say."

  "No, Randi," Ed pleads, "too dangerous-"

  "Push, damn it! Now!"

  I hear the crack of the detonation.

  "Randi?" I call, and claw my way toward the signals, white sand and occasional rocks still streaming by me. Somehow, though, it seems a bit easier. "Randi, Ed?"

  "Wojciech, Ed. We-we're free. At-at least the rock's split. Need help with Eloni."

  "I'm trying." I pant. "Where's Randi?" I am exhausted struggling against the continuing stream of material from above. I reach forward with my hand and hit flesh. Someone there. The world is gray in my helmet lamp; I can see nothing. "Ed, is that you?"

  "Not me, mate. It's slackening a little. I've got some space."

  The someone moans. The groan is female. "Eloni?" I push the person in front of me again, harder. "She's with me, Wojciech," Ed says. "Randi?"

  She grunts. "Wojciech. I'm OK. I'm just ... stuck. Legs won't move." I feel a hand brush mine, then lock with mine. "Drag me back."

  "I'll try." Trusting the precarious hand link, I sit up into the flow of clathrate mud. It tries to take me away with tremendous force, but my line holds me. Slowly I get my legs around in front of me and pull as hard as I dare. She doesn't move.

  "It's no good. I'll hurt you if I pull any harder."

  "Freezing's worse. Hurt me. Pull."

  God knows how much force I put on her arm, but something seems to unstick, and she comes toward me, slowly at first; then something breaks free and we scoot back about four meters. I can see through whirls of snow here. I can see my clip still on the bridge line, see Randi strung out at the end of my arm.

  "Dr. Lotati, she's out. Over here."

  "What? Wojciech? Where? ... There, I have you! I'll be right over."

  He is there in a moment. "Had you on the other side of the bridge for a moment-propagation freak, I think. Randi, will you be all right for a few minutes?"

  "Hurts like hell, Dad, but yes. Thanks, Wojciech."

  Dr. Lotati gives her a pat and plunges into the remains of the ice fall. Minutes later, he and Ed emerge, carrying Eloni between them. "Mike, Karen, this is Emilio," he says. "We're all out of the avalanche. I don't know in what shape yet, but we're all out."

  "Roger. We suggest all of you rest a bit until this plays itself out."

  "Mike .. ." He pauses, catching his breath. "We'll consider that."

  There are several rueful chuckles, and we spend the next five minutes or so watching the river of white dust slowly come to a halt.

  Finally the ice fall abates entirely and we take stock. Randi reports a severe sprain in her right shoulder. Ed is recovering from hypothermia and is severely bruised as well. Eloni is better, physically, but appears to be in some kind of psychological shock. The rest of us have minor bruises.

  The side of the crevasse looks like a giant took a huge, semicircular bite out of it. Karen and Mark wave at us from an edge that is now at least fifty meters back from where it was. We lost two long lines, buried in the debris. The avalanche has buried half the bridge and I worry that it could start again at any time and bury us along with the other half. I try to do some mental calculations on how long it would take a suborbital hopper to get here and pull us out.

  "I think we are here for a while," Dr. Lotati says, "at least until we're all up to climbing out again. We might overnight on the bridge." If he's worried about the avalanche restarting, he isn't saying so.

  "We'll need to revise the schedule a bit," Ed adds. "Another five kilometers per day would do it, I should think. Now, how do we get the gear down here?"

  "Toboggan the big tent down to us," Randi says. "Meantime, collect data."

  I stare at Randi, stupefied.

  "Are you OK, Eloni?" I ask, mainly out of concern but perhaps with a secondary agenda of reminding people of something.

  Eloni raises her head and looks around in wonder. If she expects a chewing out, it seems she is in the wrong group. I lay a hand very gently on her shoulder, and, as if I touched some kind of hidden button, she leans into me and lets out a very long sigh, which I hear clearly where my helmet touches her. Randi is looking right at us, but in the glare of our headlights, her face is unreadable. Warning bells ring in my head.

  "My mistake, Eloni," Ed says, "pressuring you like that for something that's not automatic. You needed to think it through, and with me talking at you like that, you couldn't. My mistake."

  "Eloni," Dr. Lotati asks, "can you help Juanita get her samples tomorrow?"

  Eloni takes a breath and slips away from me. "I-I can do that." A smile of relief creases the young woman's features.

  "That a way!"

  "Randi?" I ask, dumbfounded. "Your arm?"

  "I'll live. Still go for the bottom, Juanita?"

  "There may be a pond of liquid nitrogen trifluoride down there-it's unprecedented."

  "Ed?"

  He looks down, then at the crevasse sides. "Why don't I help Randi with the camp and prepare for climbing out of here?"

  Apparently, we will sleep here-under the sword of Damocles. "Wojciech?" Dr. Lotati asks.

  I am at a loss for words. I am more tired and sore than I have ever been. How much more tired and sore can I be before I am a danger, I wonder? Everyone has been puireled and challenged. But these people, these comrades of mine, will not admit disaster. They will press on. It is a collective decision-a spontaneous informal vote of voices that is already a majority. Voicing misgivings on my part would do no good at all, and my fate is tied to theirs. But I wonder that such things can still be in this age of robots. May the ghosts of Byrd, Amundsen, Lewis and Clark, and Bering fill my mind with whatever it is that gets one through. I came here to prove myself worthy and now the question is upon me. I look at the crevasse sides and down into its deep. "Three climbers would be best," Dr. Lotati says. "I'm ... I can go with a little rest."

  Dr. Lotati nods. "We can all use some. It's only 1100. We'll set up on the bridge. Mike and Karen, we'll take the big tent-you can probably slide it down on ropes.

  This only takes a few minutes. We anchor the large vacuum tent to the bridge. It fits with about a meter to spare in width-with the door toward the intact wall. Room in the tent is limited. It was meant to sleep four and it is crowded with six of us. Our body odors again mingle in a forgettable stew of smells, and the drop curtain for its tiny commode is woefully inadequate for privacy. But we are relieved and happy-we have been through a memorable adventure and nobody has gotten killed.

  Ed is quiet, eats quickly, and is asleep in his sack, fully clothed, in minutes. He says nothing. We will take a very real risk shortly, far, far, from help-for the sake of samples that could easily be gathered by robots a month from now.

  As a certified-and some might say certifiable-poet, suicidal undertakings are perhaps in my nature. But the milieu of the Gentleman Adventurer requires that one return from the adventure to recount it. While Ed was gallant in the crisis, the closeness of his brush with death might only now be sinking into him. I, with far less experience, accepted a challenge he did not-does he resent this?

  No, I tell myself, he is just exhausted.

  I have to make myself eat-I'm hungry, but more tired. A warm sleep-sack never felt so good, I realize. It seems I have barely closed my eyes when Dr. Lotati is gently
rocking me awake.

  "It's 1400," he says. "Time to go."

  The trip to the bottom of the crevasse is a straightforward rappel. With Randi resting her arm, Eloni and I head for the bottom with Juanita in the lead.

  "This could be Calorian clathrate-proof that Chao Meng Fu is older."

  "But doesn't its flatness mean it's young?" I ask. Old surfaces are heavily cratered.

  "Watch for a hollow to your left. No, the surface is young due to deposition, the crater itself is ancient. I'd guess we're about 3.8 billion years down, below the original crater floor. The walls are shock-fractured rock, not exposed sediment layers. No strata-" a swing of her ax tears a rough section of about a square meter from the wall "-underneath."

  "Look, more signs of erosion," she adds later.

  "Erosion?" The wall is a rough breccia, a compressed clathrate and gravel mixture. The larger stones are sharp, not rounded.

  "There is evidence of atmosphere all around us-you can see icicles in the hollows, and a cold glistening wetness on the walls."

  I turn off my radio. "Can you hear me?" I shout.

  There is no answer-the vapor is still too thin, even at the bottom, to conduct sound.

  We hang from the wall and gaze into the utterly still pool of nitrogen trifluoride in the circles of our helmet lamps below us. Unable to resist the temptation, I reach into one of Mercury's nostrils and break off an icicle and toss it into the pool. It ripples like oily water.

  "Wojciech," Eloni says in a mildly scolding voice, "have some respect! That pool has been built up, molecule by molecule, probably over billions of years."

  "How?" Juanita asks, gently. "Even if the crater is that old, the crevasse isn't."

  Eloni is silent, then says, "Oh, of course. But where does it come from then?"

  "The pool is a mystery, for now," Juanita says. "Perhaps some comet with an unusual concentration of fluorine ices struck not too long ago. Or something else." She laughs. "Fortunately, not all mysteries can be solved now. We would run out of things to do!"

  I envision tentacles reaching out of that deep to pluck us from the crevasse wall. "Could something have evolved to base its blood on that, the way we use seawater?"