Read Online Rainbow Mars by Larry Niven - Free Book Online Page B

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?”
    â€œMake us a better offer.”
    â€œThe 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.
    â€œThe 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!”
    â€œI 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—”
    â€œYou can’t breathe pre-Industrial air!” Zeera laughed. “It nearly killed Svetz on his first trip.”
    â€œNearly killed us all once,” Svetz said.
    â€œMy fault,” Zeera said. “I gave steam cars the edge at the beginning of the Industrial Age.”
    â€œThe change shock hit us and everyone stopped breathing and fainted. I got us into filter helmets—”
    â€œIf it wasn’t for temporal inertia, we couldn’t have fixed anything. There wouldn’t have been an Institute or a time machine.”
    â€œSee, 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.”
    â€œOf course I mean humans! When the air changed, why didn’t every human being on Earth change over to breathing pre-Industrial air?”
    â€œThe change shock moves at different rates,” Zeera said. “We might all have suffocated waiting. Or strangled, if we changed before the air did.”
    â€œ 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