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.
The room was immense. It extended into the distance farther than the resolution of the video devices carried by the robots. The ceiling was about twenty meters high and the two side walls were separated by more than fifty meters. Several other similar spherical objects encased in spongy masses could be seen scattered about the room in the distance. A lattice, stretching almost all the way across the room but stopping five meters above the floor, dangled from the high ceiling in the foreground. Another lattice could barely be discerned a hundred meters or so behind the first one.
Richard and Nicole discussed what the robots should do next. There were no other exits from either the subway station or the large room. A panoramic image around the room revealed nothing nearby of interest except the sphere embedded in its spongy exterior, Nicole wanted to bring the robots back and leave the lair altogether. Richard’s curiosity demanded at least a cursory investigation of one of the spherical objects.
The two robots were able, with some difficulty, to climb around and through the webbed material to reach the sphere in the center. The ambient temperature increased as they neared the sphere. One of the purposes of the external material was clearly to absorb heat. When the robots reached the nested sphere, their internal monitors flashed a warning that the outside temperatures exceeded their safe operating limits.
Richard moved quickly. Directing the robots on a nearly continuous basis, he determined that the sphere was virtually impenetrable and was probably made of a thick metal alloy with a very hard surface. Falstaff banged on the sphere several times with his arm; the resulting sound damped quickly, indicating the sphere was full, possibly with a liquid. The two robots were weaving their way out of the sponge webbing when their audio systems picked up the sound of brushes dragging against metal.
Richard tried to speed up their escape. Hal was able to increase his pace but Falstaff, whose subsystem temperatures had risen too high during his proximity to the sphere, was prevented by his own internal processor logic from accelerating his actions. The brush sound continued to grow louder.
The computer monitor on the ledge between the two cosmonauts was changed to split screen. Prince Hal reached the edge of the sponge, hit the floor, and headed for the subway without waiting for his companion. Falstaff continued to climb slowly through the webbing. ” Tis too much work for a drinking man,” he mumbled, as he crawled over another barrier.
The dragging metal sound abruptly stopped and Falstaff’s camera recorded an image of a long, skinny object with black and gold stripes. Moments later the camera frame went to all black and the little robot’s “Terminal Fault Imminent” alarm began to sound. Richard and Nicole had one more fleeting glimpse of a picture from Falstaff; it showed what might have been a giant eye, from up close, a black gelatinous mixture tinged with blue. Then all transmissions from the robot, including emergency telemetry, abruptly ceased.
Meanwhile Hal had entered the waiting subway. During the several seconds before the subway left the station, the ominous dragging sound was heard again. But the subway departed anyway, with the robot inside, and started speeding through the tunnel toward the two cosmonauts. Richard and Nicole breathed a sigh of relief.
Not more than a second later a loud sound like breaking glass was picked up by Prince Hal’s audio system. Richard commanded the robot to turn in the direction of the sound and Hal’s camera photographed a solitary black and gold tentacle in midair. The tentacle had broken the window and was moving inexorably toward the robot. Both Richard and Nicole realized what was happening at the same moment. The thing was on top of the subway! And it was coming toward them!
Nicole was climbing the spikes in a flash. Richard wasted several valuable seconds picking up his computer monitor and putting all his equipment in the backpack. He heard Prince Hal’s Terminal Fault Imminent alarm when he was halfway up the spikes. Richard turned around to look just as the subway pulled into the tunnel below him.
What he saw made his blood run cold. On top of the subway was a large dark creature whose central body, if that’s indeed what it was, was flattened against the roof. Striped tentacles extended in all directions. Four of them had pierced the windows of the train and grabbed the robot. The thing quickly climbed off the subway and wrapped one of its eight tentacles around the lowest spikes. Richard didn’t watch anymore. He clambered up the rest of the cylinder and started racing through the tunnel at the top, following the steps of Nicole far ahead of him in the distance.