Rainbow Mars

by Larry Niven

  They talked further. Svetz was glad of the company.

  At 90,000 klicks the tree had narrowed as much as it was going to, its diameter no more than a city block. Thirty thousand klicks farther out, he could see how the tree swelled into a knob. It looked like … If he could cut into that, would he find an encysted asteroid, swallowed for ballast?

  No telling, ever.

  He brought the rising X-cage to a stop. Now he had only about four minutes to play with. “Thaxir,” he asked, “do you know how to work the cannon?”

  Thaxir said, “Yes. Do you know better than to fire it against a closed door?”

  Svetz didn’t move. “Yes. What now?”

  “Wait. Are you armed with your sleep-thing?”

  He didn’t reach or look. “Yes, both of us. Miya, are you tracking this?”

  “Ready, Hanny.”

  Thaxir shouted a single syllable.

  It galvanized the Martians. They began screwing down helmets and zipping zippers and placing stickstrips on themselves, their elders and children. The translator was saying, “Close your outer skin or burst—” Svetz pulled his own helmet closed and saw Miya do the same. He tapped the icon that would suck away the air in the shell.

  A beam of white heat missed his forearm and plunged deep into the controls.

  Svetz threw himself backward. A fireball blasted back out of the hole and somehow missed fusing his helmet as it puffed across the diameter of the X-cage. Svetz fired in the direction the beam had come from. Miya was firing too. Their sonics swept the Softfinger gunman and several others.

  Elsewhere, another Softfinger loosed itself at Thaxir with a leap that spun it like a buzz saw. Its spin caressed the net-bound Thaxir, and Svetz held his aim and waited—dared not put Thaxir to sleep!—waited, and fired. The pinwheel octopoid spun away, slack and senseless. A knife spun free.

  Thaxir lifted herself free of the slashed net. “If you can still open the door,” she said, “do it.” She closed her helmet.

  The gunman’s aim had been precise. The heat beam had put a hole in the left branch of the horseshoe control board. That array controlled air composition and pressure, lights, recorded warnings, and of course, the door.

  Thaxir joined Miya at the trigger housing. The translator picked up her speech. “I persuaded some among the Softfingers that if they cut me loose, I could fire the cannon while the door was closed. We would die. The Earth would die. The tree would survive to carry the rest of our races to the stars, if we could change the future and survive the tree itself. In any case they would have their vengeance.”

  In the quantum-randomized future, Ra Chen was dead or never born; but his urgency (Advise me, Svetz!) lived on in Svetz’s mind. (Think!)

  “They revealed to me what weapons they still have,” Thaxir said. “A knife to free me, a heat gun to ruin your door lock, both swallowed in sealed bags—”

  “Swallowed?”

  “To be disgorged at need, Miya. I alerted you and trusted your reactions. The rest was up to you.”

  There was vacuum inside and out. Martians of every description were shouting at each other in silence. The large X-cage had sucked the air back into its tanks.

  Good enough. Svetz touched the remote. “Willy!”

  Nothing. He remembered to plug the jack into his suit mike. “Willy!”

  “How’s it going?”

  “Willy, you need to use the remote controls to open the door in the large extension cage. Do it now. Right now.”

  “Hanny, nobody showed me how.”

  “Don’t panic. I’ve used these myself. Now, right in front of you, you should see…” He talked Willy through it. We are the masters of time …

  The door opened like a flower.

  More Softfingers had cut themselves free. Svetz shot them with sonics as they moved.

  A thread of light burst from the cannon’s mouth. It was searing-bright until it impacted the tree four or five klicks away. Then the intensity became intolerable.

  Miya and Thaxir seemed to have the cannon under control. A halo of gas and particles surrounded the tree now, illuminating the plasma beam.

  The tree tore apart.

  The severed end was rising. Sap sprayed into space, boiling and freezing into a vast white plume. Nothing much seemed to be happening to the main body of the tree. “Turn it off,” Svetz said into his suit mike.

  “Hanny, we don’t have instructions for that. Thaxir says that wasn’t supposed to be needed.”

  “Well, if you don’t turn it off we can’t close the door, and then we can’t go home, and the energy buildup will blow the Institute off the map, and us too. But we did it. We won. There will be a future.”

  The beam went off. “Got it,” Miya said.

  “Willy, are you still on? Close the door for us. Willy, stop filming and close the door on the large X-cage. Willy!”

  The door closed. Willy Gorky said, “Patience is an underrated—” But Svetz pushed the go-home and the voice went away.

  41

  PHAETHON n. Class. Myth, a son of Helios who borrowed the chariot of the sun for one day and drove it so dangerously close to earth that Zeus struck him down with a thunderbolt to save the world from catching fire.

  —Random House Dictionary of the English Language

  The main dome was crowded to the teeth. Every face showed triumph … until they looked into the large X-cage.

  Ra Chen barely flinched, but Svetz caught it. A few techs looked bewildered; a few were frightened; some gaped, then laughed. Of sixty or seventy present, half were wearing United Nations Security uniforms, and they showed no emotion at all.

  Body language told Svetz what man was the Secretary-General. He and his guards were off to one side, and Ra Chen with him.

  The Secretary-General was no bigger than Svetz. The crown of his head was bald. Otherwise he bore thick brown hair, eyebrows and beard. At sight of a crowd of Martians he started forward, wild with delight.

  Security blocked him. Any attack on the SecGen would take Ra Chen too. An attack from the large X-cage would fall upon guards and techs first. The large extension cage had last come here as an act of war, but UN Security didn’t know that. They were only being prudent.

  And of course everyone was waiting for Svetz to open the door.

  The noise the Martians were making died a little. They were fainting in Earth’s gravity. Svetz and Miya set about cutting the nets.

  The small extension cage faded into view. Svetz saw rage flash in Ra Chen’s expression, but he covered by moving briskly to help Willy Gorky out.

  Willy delayed for a moment at the controls.

  The door unfolded like a great flower. Thank you, Willy! A door big enough to pass Whale allowed a dozen techs to swarm in. They came out carrying Martians.

  Ra Chen must have assembled every lifter platform in the UN Research Complex. As quickly as they could, they got the Martians into low gravity, stripping them of weapons where they could. No doubt the Softfingers kept a few swallowed. Svetz and Miya helped, trying to keep species separate, setting infants in bubbles among their own folk. The techs didn’t seem to think that was important, but it might be worth Thaxir’s life.

  The Secretary-General was bubbling with questions. The guards wouldn’t let him near the Martians yet, so he made do with the Heads. Willy Gorky was just a bit diffident with the SecGen and Ra Chen. Ra Chen was cordial and brisk and gave way to both.

  My time line, and it’s really Waldemar the Eleventh, Svetz decided, but the World Tree’s Willy Gorky. A dominance dance between the two Heads should be fun to watch, given that they each thought they’d lost to the other. Now Willy was pulling heavy golden spheres from a pouch and handing them ceremoniously to the Secretary-General. UN guards intercepted the seeds.

  The last of the Martians, a six-generation family of reds, was being floated away.

  Ra Chen eased free of the others. “Excellent work, Svetz! Those seeds will look really good in the Palace. Maybe we can gr
ow a few trees.” Ra Chen’s grip closed like iron on Svetz’s forearm. “We need to talk.”

  “Set guards for Thaxir, Boss,” Svetz murmured, smiling. He was being pulled outside, through the front. “Guard the Martians. They’ll kill our source if we just turn them loose in a Vivarium cage. Thaxir’s one of the older green—”

  “First things first, Svetz. How did you and Willy Gorky change places? And why?”

  “What?”

  The wonderful, elaborate drinks dispenser was back. Ra Chen pulled him past it and outside.

  “We sent you back in the small X-cage. We needed to know if any of the Martians were setting us up for something. Willy Gorky just had to go back and rescue sixty Martians himself. His first trip through time, and nobody had the least idea what these creatures really have in mind. If anything happens to the Head of Sky Domains, we’re finished,” Ra Chen said. “And now you’re back, but the Head of Sky Domains is in the small X-cage and you’re in the big one! Svetz, is this another one of those?”

  The reflecting pool was back too.

  Svetz said, “Changes in the past. Other time lines. Those, yes, Boss, but let’s just deal with the martian refugees first. Then I’ve got a great story and Willy’s got visual aids to back us up.”

  * * *

  The severed treetop rose like a comet, spraying a tremendous frosty comet-tail lit by raw sunlight. Long after the treetop itself was out of view, the trail of frost continued to expand.

  Gorky had most of the tree in view in a wraparound shot that filled the display wall. Svetz could see it all.

  At first the tree seemed unchanged. But its center of mass was below geosynchronous orbit. Left to itself it would have moved in a closer, faster orbit; but it couldn’t. It was anchored. The mass pulled ahead of the rotating Earth, and the Earth pulled back, slowing it, lowering its orbit farther.

  The bottom of the tree, the root, was still anchored to the earth more than an hour after Miya and Thaxir had severed the top. The Tree tilted forward, arcing toward horizontal. Then, deep in the bedrock of Brazil, roots ripped free. The tree pulled away, carrying away a disintegrating black clot of anchor grove.

  Now tidal forces began to swing it back to vertical. The lower end dropped until the Hangtree’s torn bottom was ripping through the atmosphere, blazing like the sun.

  The bottom of the tree was a meteor trailing flame and smoke all around the Earth. Prairies and forests blazed in its wake, a noose of fire circling the planet. Above the atmosphere, Yggdrasil’s mass pulled it along. The tree was burning at the bottom as it sank toward the Earth.

  “The legend of Phaeton,” Miya breathed.

  “No, that happened way earlier,” said Svetz.

  “Why, Hanny, don’t you believe in time travel?”

  Futz.

  No wonder the medieval world was afraid of comets. If such a mass had fallen all at once, at or near orbital speed … well, legends would have told that tale too.

  Gorky, Ra Chen and the Secretary-General engaged in intense discussion within a horseshoe of guards.

  They summoned Miya. Talk continued.

  A UN guard went for refreshments, not to the ITR dispenser but to the limousines. They summoned Zeera. Svetz bought and ate a carton of dole yeast, then another.

  They summoned Svetz.

  He told the tale as if they hadn’t heard it twice already. Prompted, he spoke of Martians left behind, the furred High Ones, the big birds who wore tool belts.

  The Secretary-General didn’t leave until midnight.

  Then Svetz dared to eat what had been sitting untouched. He and Miya snatched food they didn’t bother to identify, in a scrambling of hands. They fed each other bits of anything interesting, laughing at each other’s greed, and belatedly thought to bring Zeera into the circle. But Zeera shied away.

  Ra Chen was talking genially to Gorky. “You had your Beanstalk. You had the solar system. Wasn’t as useful as you thought, was it, Head?”

  “Ra Chen, I still have it. Hillary?—drown me, they’ve all gone home! I don’t blame them.” Willy raised his voice. “Who knows how to work the holo projector? I want just that first bit back.”

  “I can do that,” Miya said.

  * * *

  Light blazed fiercely from the World Tree. Fog haloed the heat ray, and then the top of the World Tree ripped free. Thirty thousand klicks of severed end rose at escape velocity. Sap sprayed at the stars—

  And again. Miya had looped the record. “This is what I meant,” Willy Gorky said excitedly, and pointed with his laser. A red dot traced the flow of fluid and steam. “I need to show this to the Martians, all the Martians—”

  “Tomorrow, Willy,” Ra Chen said gently.

  Willy sagged. This was the World Tree’s Willy Gorky, half starved in a starving world, the Willy Gorky whose Bureau of the Sky Domains had been eaten by the Institute for Temporal Research. In this spacetime he was master, but he was tired.

  “Go home,” he said, “find beds. Tomorrow. If only I had a time machine!”

  * * *

  They set the holo projector up in the Vivarium, outside the cage that held five martian civilizations in miniature. Martians watched them, and discussed what they were seeing.

  There were sound pickups in the Mars cage, as in all the cages—the sounds an animal made might be of interest—but no speakers. Techs linked speakers to UN translators programmed with what Svetz’s translator had learned of Mars. Wilt Miller mounted them inside the Mars cage. Five varieties of Martian watched them do it.

  As soon as they were out, the froglike Martians—the Smiths—swarmed over the devices and took them apart before Gorky could begin speaking.

  Willy Gorky waited with amazing patience. They waited with Willy, until Zeera lost patience and went four cages down to tend Horse. The rest stayed.

  Horse seemed glad of the attention.

  In present time, one need not credit a children’s story.

  But Svetz knew that they had lost the Zeera of the baths, the Zeera who turned a conquistador into gold, that Zeera who had stayed with that Ra Chen in another time line so that they could destroy it. That Zeera would not be petting Horse.

  When the Smiths had reassembled the translators, Willy Gorky told them, “I can restore your planet.”

  No Martian spoke. Svetz’s eye found Thaxir among the green giants. He was relieved: she sat dignified and straight among her kin.

  Willy said, “What I need from you is transportation. I know you didn’t bring any kind of spacecraft, but you know things. I want to know how your wok ships work. I need to know how to make a gas lighter than nothing. Anything that helps me reach the planets is worth having.

  “Think about it. Tonight I will show you how.”

  * * *

  Daylight would have washed out Willy Gorky’s hologram recordings. They had to wait for night.

  Zeera still had seeds: heavy golden spheres hardened against reentry. It took jeweler’s equipment to open them. Inside they were built like pomes. The laboratory’s first attempt at a DNA scan failed. It must be some other genetic molecule that reproduced a Beanstalk anchor tree. They’d find it.

  Willy worked with the Bureau of the Sky Domains’ astronomers. They knew what to look for now. The world’s telescopes were turned on Europa. Data began flowing back.

  * * *

  The Vivarium, nightfall:

  The severed ends of the World Tree came apart, trailing oceans of water in a wide frosty comet tail. The blood of the tree sprayed across the sky.

  Willy Gorky spoke for the translators in the Martians’ housing. “It goes on and on. Gigatons of sap, mostly water infused with oxygen and some interesting nutrients—I zapped it with a laser to get a spectroanalysis—”

  An elderly Smith had come forward. “Our world’s water,” he said. “Other species stayed to share the fate of our dying world. The tree was our destiny.”

  Willy didn’t miss a beat. “Our fate too, but we side-stepped. Your w
orld’s water, yes. Now I’ll show you how to get it back.”

  And he showed them.

  * * *

  A sapling left at Mars fifteen hundred years ago had sucked away that world’s remaining life. What it sensed of its parent’s fate was unknowable. How do trees communicate? But on this time line, the Hangtree had been chopped down and killed at Earth.

  When its sapling child had as much water as Mars had to give, it had moved, still feeble, outward.

  The sapling was at Europa. Given that the ancient Mariner probe had found no Hangtree at Mars, it must have been at Europa for at least a thousand years.

  In the holo view it was a mere silver thread, as thin as imagination, but it was long. Its center of mass stood well out from Europa, in the stable L2 point made by Europa and Jupiter.

  “Did you learn anything about guiding the Hangtree?” Willy looked hopefully up at the rows of alien faces. “Europa is a water ocean under a shell of ice. That thing is sucking it up. All we need to do is guide it back to Mars. Then chop away the root and bleed its veins dry, let the sap drain into the old canals and ocean beds. Oceans of water. Sugar and nutrients for fertilizer. You’ll have a world again.”

  Willy’s voice rang. “But we can’t get there from here. Earth’s gravity is greater, our space program is a pitiable thing, our rockets can barely lift themselves. But with those and your antigravity dirigibles or your wok ships to lift them free of Earth’s gravity, we can get there. We can get anywhere.

  “We’ll make Mars live again. Will you help me?”

  He had them. Without being able to read alien faces, Svetz still knew: he had them.

  * * *

  “It’s not what I really wanted,” Willy Gorky admitted later. “It’s a thousand years too late. I wanted to take the planets while the Earth was still rich.”

  Ra Chen had formed his attitude long ago. Thou shalt not change the past. Not by accident, not deliberately. Disaster and chaos will result.

  He said, “Willy, you’d have roughly ten productive years if you marooned yourself in the twentieth century. No conspicuous technology means no modern medicine and no UN translators. We could train you in their language, but you’ll still have an accent nobody can define—”