Rama 2 by Arthur C. Clarke and Gentry Lee

Richard had walked over beside the vehicle. A door in the side had opened and they could both see the lit interior. There were no seats, only thin cylindrical poles, spaced in no obvious pattern, that ran the three meters from the ceiling to the floor. “It can’t go far,” Richard said, sticking his head inside the door but leaving his feet on the ledge outside. “There’s no place to sit down/’

Nicole came over to inspect for herself. “Maybe they have no old or crippled people—and the grocery stores are all close to home.” She laughed again as Richard leaned farther into the car so he could see the ceiling and walls more clearly. “Don’t get any crazy ideas,” she said. “It would be certifiably insane for us to climb aboard that car. Unless we were out of food and it was our last hope.”

“I guess you’re right,” Richard replied. He was definitely disappointed as he withdrew from the subway car. “But what an amazing—” He stopped himself in midsentence. He was staring across the platform at the opposite side of the ledge. There, in the middle of the now illuminated entrance to the tiny tunnel, an identical vehicle, one-tenth the size of the one next to them, was hovering off the floor. Nicole followed Richard’s gaze.

“That must be the road to Lilliput over there” Nicole said. “Giants descend another floor and normal-size creatures take this subway. It’s all very simple.”

Richard walked swiftly around the ring. “That’s perfect,” he said out loud, taking off his backpack and setting it on the ledge beside him. He began to rummage in one of the large pockets.

“What are you doing?” Nicole asked.

Richard pulled two tiny figures out of the pack and showed them to her. “It’s perfect,” he repeated, his excitement unmistakable. “We can send Prince Hal and Falstaff. I’ll only need a few minutes to adjust their soft­ware.”

Already Richard had spread his pocket computer out on the ledge beside the robots and was busily working away. Nicole sat down with her back against the wall between two spikes. She glanced over at Richard. He is truly a rare species, she said with admiration, thinking back over their hours to­gether. A genius, that’s obvious. Almost without guile or meanness. And somehow he has retained the curiosity of a child.

Nicole suddenly felt very tired. She smiled to herself as she was watching Richard. He was absorbed in his work. Nicole closed her eyes for a moment.

“I’m sorry that I took so long,” Richard was saying. “I kept thinking of new things to add and I needed to rearrange the linkage …”

Nicole woke up from her nap very slowly. “How long have we been here?” she said as she yawned.

“A little over an hour/’ Richard answered sheepishly. “But everything is all set. I’m ready to put the boys in the subway.” Nicole glanced around her. “Both the cars are still here,” she commented.

“I think they work like all the lights. I bet they will stay in the station as long as we’re on the platform.”

Nicole stood up and stretched. “So here’s the plan/’ Richard said. “I have the controlling transceiver in my hand. Hal and Sir John each have audio, video, and infrared sensors that will acquire data continuously. We can choose which channel to monitor on our computers and send new com­mands as necessary.”

“But will the signals penetrate the walls?” Nicole asked, remembering her experience inside the barn.

“As long as they don’t have to travel through too much material. The system is way overdesigned in terms of signal to noise to accommodate some attenuation. . . . Besides, the large subway came at us along a straight line. I’m hoping this one will be similar.”

Richard gingerly set the two robots down on the ledge and commanded them to walk toward the subway. Doors opened on both sides as they drew near. “Remember me to Mistress Quickly,” Falstaff said as he climbed aboard. “She was a stupid lass, but with a good heart.”

Nicole gave Richard a puzzled glance. “I didn’t overwrite all their earlier programming,” he said with a laugh. “From time to time they will probably make some absurd random comments.”

The two robots stood on the subway for a minute or two. Richard hastily checked their sensors and made one more set of calibrations on the monitor. At length the doors of the subway closed, the vehicle watted for another ten seconds, and then it rushed away into the tunnel.

Richard commanded Falstaff to face the front, but there was not much to be seen out the window. It was a surprisingly long ride at a very high speed. Richard estimated that the little subway had traveled more than a kilometer before it finally slowed to a stop.

Richard waited before commanding the two robots to leave the subway. He wanted to make certain that they did not get off at an intermediate stop. However, there was no need to worry: the first full set of imaging data from Prince Hal and Falstaff showed that the subway had indeed reached the end of the line.

The two robots walked around the flat platform beside the vehicle and photographed more of their surroundings. The subway station had arches and columns, but it was basically one long, connected room. Richard estimated from the images that the ceiling height was about two meters. He commanded Hal and Falstaff to follow a long hallway that moved off to the left, perpendicular to the subway track.

The hallway terminated in front of another tunnel, this one barely five centimeters high. As the robots examined the Boor, finding two tiny strips extending almost to their feet, a subway of minuscule proportions arrived in the station. With its doors open and its interior lit, Richard and Nicole could see that the new subway car was identical, except for its size, to the two they had seen before.

The cosmonauts were sitting together with their knees on the ledge, both avidly watching the small computer monitor. Richard commanded Falstaff to take a picture of Prince Hal standing next to the tiny subway. “The car itself,” Richard said to Nicole after studying the image, “is less than two centimeters tall. What’s going to ride in it? Ants?”

Nicole shook her head and said nothing. She was feeling bewildered again. At that moment she was also thinking about her initial reactions to Rama. Never in my wildest imagination, she thought, recalling her awe at that first panoramic sight, did I foresee that there would be so many new mysteries. The first explorers hardly scratched the surface—

“Richard,” Nicole said, interrupting her own thoughts.

He commanded the robots to walk back down the hallway and then glanced up from the monitor. ‘Yes?” he said.

“How thick is the outer shell of Rama?”

“I think the ferry covers about four hundred meters altogether,” he said with a slightly puzzled expression. “But that’s at one of the ends. We have no definite way of knowing how thick the shell is anywhere else. Norton and crew reported that the depth of the Cylindrical Sea was highly variable—as little as forty meters in some places and as much as a hundred and fifty elsewhere. That would suggest to me a shell thickness of several hundred meters at least.”

Richard checked the monitor quickly. Prince Hal and Falstaff were almost back at the station where they had climbed off the subway. He transmitted a stop command and turned to Nicole. “Why are you asking? It’s not like you to ask idle questions.”

“There’s obviously an entire unexplored world down here,” Nicole replied. “It would take a lifetime—”

“We don’t have that long,” Richard broke in with a laugh. “At least not a normal lifetime. . . . But back to your thickness question, remember the entire Southern Hemicylinder has a floor level four hundred and fifty meters above the north. So unless there are some major structural irregularities—and we certainly haven’t seen any from the outside—the thickness should be substantially greater in the south.”

Richard waited for Nicole to say something additional. When she re­mained silent for several seconds, he turned back to the monitor and contin­ued his surrogate exploration with the robots.

There had been a good reason for Nicole’s question about the thickness of the shell. She had a picture in her mind that she could not shake. Nicole was imagining coming to the end of one of these long underground tunnels, opening a door, and then being blinded by the light of the Sun. Wouldn’t it be incredible, she was thinking, to be an intelligent creature living in this maze of dim light and tunnels and then, by chance, to stumble onto some­thing that would irrevocably change your entire concept of the Universe? How could you return—

“Now what in the world is that?” Richard was asking. Nicole stopped her mental drifting and focused on the monitor. Prince Hal and Falstaff had entered a large room at the opposite end of the subway station and were standing in front of a conglomeration of loose, spongelike webbing. The infrared image of the scene showed a nested sphere, inside the web, that was radiating heat. At Nicole’s suggestion, Richard commanded the robots to walk around the object and survey the rest of this new domain.