The Ringworld Engineers

Despite the contoured ocean floor, Earth was easy to recognize. Louis pointed out the flat curves of the continental shelves as they passed beneath Africa, Australia, the Americas, Greenland… fins under Antarctica and the Arctic Ocean… the Ringworlders watched and nodded politely. Why would they care? It wasn’t their home.

Yah, he’d do his best to get Harkabeeparolyn and Kawaresksenjajok home, if there was nothing else he could do for them. Louis Wu was as close to Earth now as he would ever be.

More sea bottom passed above them.

Then shoreline: a flat curve of continental shelf bordering a maze of gulfs and bays and river deltas and peninsulas and island clusters and raggedy detail too fine for the human eye. Needle ran on to port of spinward. They passed beneath hollow mountain ranges and flat seas. A finely ruled line ran straight to spinward, and at its near end, a glint of light—

Fist-of-God.

Something huge had struck the Ringworld long ago. The fireball had pushed the Ringworld floor upward into the shape of a tilted cone, then ripped through. Pointing almost away from that great funnel shape was the track of a much later meteorite: a crippled General Products spacecraft, with its passengers frozen in stasis, had touched down at a horizontal seven hundred and seventy miles per second. Futz, they’d actually bent the scrith!

Hot Needle of Inquiry rose into a spotlight beam: raw sunlight flooding vertically through the crater in Fist-of-God Mountain. Shards of scrith, stretched thin when that old fireball broke through, stood like minor peaks around a volcano cone. The ship lifted above them.

Desert sloped down and away. The impact that made Fist-of-God had cremated all life over a region comfortably larger than the Earth. Far, far away, a hundred thousand miles away, the blue of distance became the blue of sea; and only Needle’s thousand-mile height let them see that far.

“Get us moving,” Louis said. “Then give us a view from the lander’s cameras. Let’s see how Chmeee’s doing.”

“Aye aye.”

Chapter 27 — The Great Ocean

Six rectangular windows floated beyond the hull. Six cameras showed the lander’s flight deck, lower deck, and four outside views.

The flight deck was empty. Louis scanned for emergency lights and found none.

The autodoc was still a great coffin, closed.

Something was wrong with the outside cameras. The view wavered and shifted and streamed with glowing colors. Louis was able to make out the courtyard, the arrow slits, several kzinti standing guard in leather armor. Other kzinti sprinted to and fro on an fours: blurred streaks.

Flames! The defenders had built a bonfire around the lander!

“Hindmost? Can you lift the lander from here? You said you had remote controls.”

“I could take off,” the Hindmost said, “but it would be dangerous. We are… twelve minutes of arc to spinward and a bit to port of the Map of Kzin — a third of a million miles. Would you expect me to fly the lander with a lightspeed delay of three and a half seconds? The life-support system is holding well.”

Four kzinti streaked across the courtyard to throw open massive gates. A wheeled vehicle pulled in and stopped. It was larger than the Machine People vehicle that had brought Louis to the floating city. Projectile weapons were mounted on its four fenders. Kzinti emerged and stood studying the lander.

Had the castle’s lord called on a neighbor for help? Or had a neighbor come to claim rights to an impregnable flying fort?

The vehicles guns swiveled to face the cameras, and spat. Flame bloomed; the cameras shuddered. The great orange cats ducked, then rose to study the results.

No emergency lights showed on the flight deck.

“These savages haven’t the means to harm the lander,” the Hindmost said.

Explosive projectiles sprayed the lander again.

“I’ll just take your word for it,” Louis said. “Continue monitoring. Are we close enough that I can get to the lander by stepping discs?”

The puppeteer looked himself in the eyes. He held the pose for several seconds.

Then he spoke. “We are two hundred thousand miles to spinward of the Map of Kzin, and a hundred and twenty thousand miles to port. The portward distance is irrelevant. The spinward distance would be lethal. It gives Needle and the lander a relative velocity of eight-tenths of a mile per second.”

“Too much?”

“Our technology is not miraculous, Louis! Stepping discs can absorb kinetic energies of up to two hundred feet per second, no more.”

The explosions had scattered the bonfire. Armored kzinti guards were building it up again.

Louis bit down on a bad word. “All right. The fastest way to get me there is to run us straight to antispinward until I can use the stepping discs. Then we can take our time running to starboard.”

“Aye, aye. What speed?”

Louis opened his mouth and left it open while he thought. “Now, that is one fascinating question,” he said. “What does the Ringworld meteor defense consider a meteor? Or an invading spacecraft?”

The puppeteer reached behind him, chewed at the control. “I’ve cut our acceleration. We should discuss this. Louis, I don’t understand how the City Builders knew it was safe to build a rim transport system. They were right, but how did they know?”

Louis shook his head. He could see why the Ringworld protectors might program the meteor defense not to fire on the rim walls. A safe corridor for their own ships — or maybe they found that the computer was firing on the attitude jets whenever the attitude jets fired a high-velocity plume of gas. “I’d say the City Builders started with small ships and built up. They tried it and it worked.”

“Stupid. Dangerous.”

“We already know they did things like that.”

“You have my opinion. At your orders, Louis: what speed?”

The high desert sloped gradually down: a baked and lifeless land, an ecology shattered and heated to incandescence thousands of falans ago. What had struck that blow from underneath the Ringworld? A comet wouldn’t normally be that big. There were no asteroids, no planets; they had been cleaned out of the system during the building of the Ringworld.

Needle’s velocity was already respectable. The land ahead was beginning to turn green. There were silver threads of river.

“On the first expedition we flew at Mach 2, using flycycles,” Louis said. “That’d take us… eight days before I can use the stepping discs. Too tanj long. I’m assuming the meteor defense fires on things that move fast relative to the surface. How fast is fast?”

“The easy way to find out is to accelerate until something happens.”

“I do not believe I heard a Pierson’s puppeteer say that.”

“Have faith in puppeteer engineering, Louis. The stasis field will function. No weapon can harm us in stasis. At worst we will return to normal status after we strike the surface, and proceed henceforth at a lower speed. There are hierarchies of risk, Louis. The most dangerous thing we can do during the next two years is hide.”

“I don’t — if it was Chmeee saying — but a Pierson’s… give me a minute.” Louis closed his eyes and tried to think. Then “See how this sounds. First we loft the ruined probe, the one we left in the Library—”

“I moved it.”

“Where?”

“To the nearest high mountain with an exposed scrith crest. The safest place I could think of. The probe is still valuable, though it can no longer manufacture fuel.”

“That’s a good place. Don’t try to fly it. Just turn on every sensor on the probe,