Rainbow Mars

by Larry Niven

  She wasn’t looking at him. Svetz realized he was missing the view.

  The bright orange point had become a disk. Not a disk now: a whirling sphere expanding much too fast. “That’s close enough,” Zeera said, and Mars jarred to a stop, as large as a full Earth seen from the Moon.

  Thus far the trip had cost them forty minutes ship time.

  “We still have to match orbit with Mars. Anything threatens us, we just go past. We’ve got fuel to abort and return. Miya, take the copilot slot.” Zeera sounded edgy, and well she might. They were rubbing up against an alien civilization. They had examined little more than its garbage, but all the corpses wore wounds.

  * * *

  The Minim slowed at a tenth of a gee, spiraling in toward Mars. The planet waned to a shrinking crescent, then a great black hole in the stars.

  They were moving inward of Deimos’ orbit, and Mars was a spreading crescent, when Svetz found the tree.

  It was foreshortened, pointing almost at the ship. The orbital tower looked like a giant’s club. They were passing just above the massive, rounded upper end.

  “Interestingly phallic,” Miya said. “Or is that just me? Hanny!” as a diseased potato thirty klicks long came straight at them. Zeera screamed.

  The hurtling moon missed them by … Watching it recede made it seem that Deimos had missed by two klicks or more, still much too close for comfort.

  Miya came out from behind her arms. She looked at Svetz for a heartbeat, her face too pale. Then she turned her attention to the planet.

  Mars was still distant by hundreds of klicks, but the Minim’s zoom display was good. Mars’ crescent grew gibbous, then full. Canal patterns laced the deserts, knotted into cities at the intersections. There was a wide white northern ice cap. Miya swore monotonously. “That region has to be Syrtis Major, but there’s nothing left of the shape! Valles Marineris is all gray-green … there, where all those minor canals converge. Zeera, every feature I know has changed. I’m feeling very lost. Wait, that’s Mons Olympus, with greenery crawling up the sides. That’s Aeolis coming over the horizon, and the tree growing out of it.”

  Craters thickened east of Aeolis. Canals crossed a few of those, the ones that held water. Mars covered half the sky. Features raced beneath the Minim, expanding. “Aeria,” Miya said, “I think.”

  “Better be,” Zeera said.

  Svetz asked, “Zeera, are you going to land us?”

  “No. Aerobrake.”

  “What’s it mean?”

  “You’ll love it. Are you webbed in?”

  The hull began to sing. A landscape of mottled ochre desert and ragged canyons and narrow gray-green lines hurled itself directly at his face, close enough to touch. Svetz clutched the arms of his chair and felt heat radiating from the window. He never thought to look at his companions. He heard Miya murmur, “Xanthe,” and saw a monstrous crater pass beneath them.

  Then the singing tapered off, but Zeera whooped and whacked his bony back. “Hell of a ride!”

  Svetz began the process of relaxing his hands.

  “This next part’s tricky,” she said.

  Thrust built up against their backs. Mars was a shrinking crescent. A hint of a vertical line was growing ahead.

  Zeera’s mind was on her flying. She talked in staggered half sentences. “Chairman Gorky’s been seven … months rebuilding the Minim. We missed the coronation, of course. We had time to run your travelogues to death … but we just weren’t seeing enough … enough of the tree. It’s Beanstalk seeds we’re after. Willy Gorky thinks the … SecGen is losing patience … but it’s really Willy.”

  “We’re not on a rescue mission?”

  “No, Hanny. If we can save some Martians, that’s in order. But first, where are the seeds?”

  “Not if?”

  “Hanny, we assume there are seeds. Seeds are wanted. Where would you want to drop seeds if you were a skyhook tree?”

  Svetz shrugged. “Deep water, for a plant that tall. The canal. An ocean, if there was one.”

  “But you looked.”

  “They aren’t there.”

  Miya said, “Hide seeds in the black fringe. Grow a cannon. Spit them over the horizon at other canals.”

  Zeera said, “The fringe runs … along the mid-trunk for more than twenty thousand klicks. You want to search all that?”

  “Make us a better offer.”

  “The fringe is like leaves on a tree, Hanny. It makes sugar. Spectrum off a laser flash showed us the chemical that does photosynthesis. It’s not chlorophyll. A separate line of evolution. It’s probably from another solar system.”

  Alien.

  “The fringe could make seeds too, I guess. You want to look in the fringes? That’s the plan, then. I’ve got us in synchronous orbit. We can study the mid-trunk before I go down.” Zeera cut the thrust and they floated.

  The trunk had grown huge. Svetz guessed it at five hundred meters thick and a couple of klicks distant. He asked Zeera, “Do we have to go down at all?”

  Miya exclaimed, “Hanny! That’s Mars down there!”

  “I like to know my options.”

  Zeera sighed. “We’ve already used up too much fuel to get home. We’ll need to land at Mons Olympus and refuel. Now make a choice. Do you want to go down the tree or up the tree? You’ve got flight sticks. I could let you off at the midpoint, then go on to refuel while you work your way down. Or you can ride down with me, maybe talk to some Martians, then fly to the tree and climb.”

  They spent a few minutes talking it over. Svetz wished they could call the Center and give the decision to someone else. No go: the talker would reach through time, but not through an interplanetary gravity gradient. They were out of contact until they could return to Earth.

  Ultimately Miya said, “Let’s get the job done first. Zeera, let us off here. We’ll work our way down and join you at Mons Olympus.”

  Miya left her seat. In one-tenth gee she fished out three transparent bags and handed two to Svetz and Zeera. “Do you both know how to use these?”

  Grinning, Svetz said, “This may never come up—”

  “You can’t breathe pre-Industrial air!” Zeera laughed. “It nearly killed Svetz on his first trip.”

  “Nearly killed us all once,” Svetz said.

  “My fault,” Zeera said. “I gave steam cars the edge at the beginning of the Industrial Age.”

  “The change shock hit us and everyone stopped breathing and fainted. I got us into filter helmets—”

  “If it wasn’t for temporal inertia, we couldn’t have fixed anything. There wouldn’t have been an Institute or a time machine.”

  “See, Miya, you’ve got to have certain substances in your blood,” Svetz said, “or your body forgets to breathe. Carbon dioxide, nitrogen oxides, sulfur compounds. You need other industrial by-products too.”

  Miya asked, “Why didn’t you change too?”

  Svetz and Zeera looked at each other. Zeera said, “You mean humans.”

  “Of course I mean humans! When the air changed, why didn’t every human being on Earth change over to breathing pre-Industrial air?”

  “The change shock moves at different rates,” Zeera said. “We might all have suffocated waiting. Or strangled, if we changed before the air did.”

  “All right,” Miya said. “We need filter helmets to breathe martian air at ground level. These aren’t stock issue, they’re altered for Mars. Note the insignia—” A thumbtip-sized orange dot on the forehead. “On Mars they have to concentrate oxygen and hold carbon dioxide and monoxide out. Don’t try to climb with just these. In vacuum you need a full pressure suit. But keep them handy.”

  Svetz and Miya donned their pressure gear and tested the voicelink. Miya showed Svetz how to back into a rocket pack, set it and lock it to his back plate.

  Nozzles faced back, up, down. Nozzles poked past his short ribs, facing forward. He was wearing high explosives on his back, and he’d known this was coming. They were in balance be
tween Mars gravity and centrifugal force. A flight stick would push up: no help.

  Miya affixed a flight stick to Svetz’s back for use when they got lower; then a blaster. “Want this too?”

  She was holding the needle gun. Svetz said, “Yes.”

  “You sure?”

  “Habit. We don’t use blasters on any normal mission. We don’t want to kill anything in the past.”

  She turned and let him stickstrip a flight stick and blaster to her back, careful to keep it all clear of rocket nozzles.

  Miya went out first.

  The skyhook tree was fat in the middle, wider than any redwood. The black foliage only began much lower down.

  “Let’s do it,” Miya said. Facing the tree, she fired her rocket pack. Svetz fired his a moment later. It kicked him toward the tree. When her flame died, he cut his off too.

  16

  … But most women, when they feel free to experiment with life, will go straight to the witches’ Sabbath. I myself respect them for it, and do not think that I could ever really love a woman who had not, at some time or other, been up on a broomstick.

  —Isak Dinesen, “The Old Chevalier,” from Seven Gothic Tales

  The mid-trunk was glossy, void of detail but for a glittering silver thread. Svetz used his helmet to zoom on it. The thread split into two parallel lines.

  “Miya?”

  “I see it. The Martians have built a lift. That’s what you do with a Beanstalk.”

  Svetz asked, “They’d have used it to explore the solar system, wouldn’t they?”

  “Time is your thing, not mine. There are lots of little moons in the outer system, some almost as big as Mars. If Martians had been there, we’d have found something. Mars must have been just starting to reach out when something interrupted. Some disaster.”

  Svetz reset his helmet view. Unzoomed, the trunk was still coming close. Far around the curve was a creasing of the … bark? It stretched for several klicks, as if a silver-gray wing were folded along the trunk.

  “Ready for retrothrust?”

  “I haven’t taken my fingers off those switches since you showed them to me.” The bark was very close.

  “Good. Hold off, though, Hanny. You see anything scary?”

  “Lift cables. We’ve got Martians above and below. Those folds: you see them? I want a better look at those.”

  “Retrothrust,” Miya said. He didn’t see her fire, but he toggled switches with four fingertips. Nozzles poking past his ribs fired. His back plate pulled him backward. The trunk came softly up to meet him.

  There was nothing to cling to.

  Zeera’s voice: “Are you on the tree?”

  Miya: “Phoenix has landed. Hanny?”

  Svetz: “Snake is on the tree. Zeera, how’s your view?”

  Zeera: “I have views through both your helmet cameras. I will call you from Mons Olympus.”

  Blue flame puffed. The Minim spacecraft receded and was gone.

  17

  Beanstalk. Universe tree of fairy tales; ladder or road to the heavens?… The rope trick of India is related to the belief in a stairway to heaven.

  —Dictionary of Mythology, Folklore and Symbols, by Gertrude Jobes

  Svetz followed Miya around the trunk. The sun shown directly on them. Svetz deployed his silver cloak like a parasol, but he was still sweating. The porous pressure suit let his own sweat cool him. Otherwise he’d have steamed himself to death.

  He asked, “Should we be wearing sunblock?”

  “The suits block UV,” Miya said.

  He drifted alongside the silver-gray crease. “Blanket big enough to cover a city. Square klicks of it,” he reported, for Miya and a later audience. He touched it. “Flimsy stuff.” He crawled under a fold of tissue-thin leaf and turned his headlamp on. He was instantly dazzled. “Yow! It’s a hall of mirrors in here.”

  “A skyhook tree could use light-sails to maneuver. Grow them like leaves.”

  They crawled around under the silver-gray leaf without finding anything but bark and mirror.

  They followed the metal rails down to a switching arrangement. “Willy would have used a maglev track, not a box on rails,” Miya said. “This must be deadly slow. Building it must have been deadly slow.”

  “Maybe they live longer. Now what?”

  “Down,” Miya said. She fired rockets and was off down the trunk. Svetz followed.

  She was nearly out of sight, but her voice remained clear. “Cut your thrust now. Hanny, use the flight stick when it’s time to decelerate. We’ve got gravity now. If you see anything on the trunk, tell me.”

  “Nothing but the cable.” He was falling. Free fall hadn’t bothered him at the midpoint. This was different. He fell alongside the tree as if he’d jumped from an arcology’s roof, falling too fast and dead already.

  “I see another silver wrinkle, another light-sail leaf. Don’t get too close to the trunk, Hanny.”

  Svetz didn’t intend to.

  “Big box on one of the cables. It’s just an open cage, barred, lots of boxes inside, some troops too. Hanny, duck.”

  “Duck what?” he asked. He still hadn’t seen the barred box she spoke of, but he fired a puff of rocket exhaust to push him sideways.

  “I’m just being cautious,” Miya said.

  There: a barred box on the rail. He zoomed his view, and saw a metalwork cage sculpted into a festival tent. Sparks lit the cage, puffs of flame from a dozen tubes. A flicker tugged at his peripheral vision: bits of metal passing silently through the space he’d vacated.

  Miya had gone past the lift before they could react. They must be shooting at Svetz.

  Carefully rather than quickly, Svetz pulled the flight stick from its tape and set it between his legs. It surged and lifted him away from another volley of what must be kinetic weapons. Faceplate magnification gave him shapes within the grillwork, just for an instant, as he hurtled past.

  He’d seen at least five species of manlike and alien creatures among the fifteen or so. Some looked like humans in gaudily decorated armor, or in plain armor but with oversized misshapen heads; some were bigger, with too many limbs; four clung to the bars, all limbs, like Octopus, who shared Whale’s cage. One was standing apart, weaponless, but he felt its regard: a cream-colored creature three meters tall, a skeletally gaunt giant fitted with great goblin ears stuffed into a fishbowl helmet.

  “Missed me twice,” Svetz told Miya.

  “Any damage?”

  “No. I’m losing you, though. Not f-falling as fast.” His teeth were starting to chatter with reaction. He’d better stop talking.

  Gravity had grown strong. The trunk slid past him ever faster, minute by minute. The band of dark foliage was still below him, but rising. Something on the trunk—

  “Miya? That row of loose struts?”

  “I see it. Artificial?”

  “No, I think that would be stems for light-sail leaves. The leaf material’s gone. Martians might have harvested it, like a farm for mirrors.”

  Miya said, “I’m going into the forest.”

  “East side, foliage strip, aye. Decelerating.” He’d never had a partner on a mission. He’d never had to coordinate every futzy move with someone else.

  The flight stick thrust up against Mars’ pull, but it gave him maneuvering range too. He needed it. He’d drifted too close to the trunk.

  He heard, “Hanny, I misjudged. I’ll be landing five or six klicks below the top.”

  “Want me to go in higher up?”

  “Do that.”

  The flight stick was steady under him. The trunk slid past, slowing. He dropped alongside black foliage, sparse at first, then thick and dense.

  Miya: “I’m on. I’m inside. Yeee!”

  “Miya!”

  “Something jumped at me. I had to shoot it. These blasters don’t leave much. Svetz, are you in?”

  “At, not in.” Svetz hovered, looking into a wall of black forest. The fluffy surface looked no more substantial than
a dandelion ready to blow. He had no real wish to go inside, and no way to avoid it. Something in there had tried to kill Miya.

  He fished out the blaster and fired into the black wall, angled down.

  Foliage flared white. There was no recoil. The blast speared straight through until the tunnel showed red Mars at its far end.

  Things swarmed out. Gravity and momentum pulled them away before he could see much of them.

  He tracked a lens-shaped creature as big as a bungalow, the last in a whole fleet. Maybe Zeera could get more detail from the recording.

  Coils of cable fell thrashing, then stretched out, klicks and klicks of it, reaching. Svetz used the zoom feature to track it. One end brushed the tree, dragged along it, caught more, loop after loop … thick cable marked with a black-on-milk diamond pattern … that was a wedge-shaped head.

  Yes indeed, there was more than one kind of snake.

  “I’ve fired a hole right through the forest. Things came out. Now I’m going straight in,” he reported.

  “Futz of a way to explore,” Miya said.

  “We’re not exploring. We’re looking for seeds. Seeds on a thing this size ought to be immense. Unmistakable.”

  “We can hope.”

  He coasted in. Coming out of the sun had him nearly blind despite his headlamp. When his eyes adjusted a bit, he jetted down the channel.

  Whatever might consider him edible must have died or fled. Twenty minutes later he let himself fall into sunlight.

  “Miya, I’m out. Have you moved?”

  “Still inside. I’m not finding anything.”

  “I’ll drop past your position by … oh, fifty klicks and go in again.” Svetz was already falling, his flight stick providing just a touch of lift.

  Miya sounded tired. “Hanny, it’s too big a job.”

  “I know. We’re missing something. We need to know where to look, but I just don’t see the right pattern yet. Zeera, are you with us?”

  No.

  “Miya, if you were a tree, you’d want to drop your seeds in water, wouldn’t you? The tree did that. Sank roots where two canals crossed.”