at the lowest point of this strange, inside-out world, but the highest. From here, all directions were down, not up. If he moved away from this central axis, toward the curving wall which he must no longer think of as a wall, gravity would steadily increase. When he reached the inside surface of the cylinder, he could stand upright on it at any point, feet toward the stars and head toward the center of the spinning drum. The concept was familiar enough; since the earliest dawn of space flight, centrifugal force had been used to simulate gravity. It was only the scale of this application that was so overwhelming, so shocking. The largest of all space stations, Syncsat Five, was less than two hundred meters in diameter. It would take some little while to grow accustomed to one hundred times that size.
The tube of landscape that enclosed him was mottled with areas of light and shade that could have been forests, fields, frozen lakes, or towns; the distance, and the fading illumination of the flare, made identification impossible. Narrow lines that could be highways, canals, or well-trained rivers formed a faintly visible geometrical network; and far along the cylinder, at the very limit of vision, was a band of deeper darkness. It formed a complete circle, ringing the interior of this world, and Norton suddenly recalled the myth of Oceanus, the sea that, the ancients believed, surrounded the Earth.
Here, perhaps, was an even stranger sea—not circular, but cylindrical. Before it became frozen in the interstellar night, did it have waves and tides and currents—and fish?
The flare guttered and died; the moment of revelation was over. But Norton knew that as long as he lived these images would be burned in his mind. Whatever discoveries the future might bring, they could never erase this first impression. And history could never take from him the privilege of being the first of all mankind to gaze upon the works of an alien civilization.
CHAPTER 9
RECONNAISSANCE
“We have now launched five long-delay flares down the axis of the cylinder, and so have a good photo-coverage of its full length. All the main features are mapped. Though there are few that we can identify, we’ve given them provisional names.
“The interior cavity is fifty kilometers long and sixteen wide. The two ends are bowl-shaped, with rather complicated geometries. We’ve called ours the Northern Hemisphere and are establishing our first base here at the axis.
“Radiating from the central hub, 120 degrees apart, are three ladders that are almost a kilometer long. They all end at a terrace, or ring-shaped plateau, that runs right around the bowl. And leading on from that, continuing the direction of the ladders, are three enormous stairways, which go all the way down to the plain. If you imagine an umbrella with only three ribs, equally spaced, you’ll have a good idea of this end of Rama.
“Each of those ribs is a stairway, very steep near the axis and then slowly flattening out as it approaches the plain below. The stairways—we’ve called them Alpha, Beta, Gamma—aren’t continuous, but break at five more circular terraces. We estimate there must be between twenty and thirty thousand steps. Presumably they were used only for emergencies, since it’s inconceivable that the Ramans—or whatever we’re going to call them—had no better way of reaching the axis of their world.
“The Southern Hemisphere looks quite different. For one thing, it has no stairways and no flat central hub. Instead, there’s a huge spike, kilometers long, jutting along the axis, with six smaller ones around it. The whole arrangement is very odd, and we can’t imagine what it means.
“The fifty-kilometer-long cylindrical section between the two bowls we’ve called the Central Plain. It may seem crazy to use the word ‘plain’ to describe something so obviously curved, but we feel it’s justified. It will appear flat to us when we get down there—just as the interior of a bottle must seem flat to an ant crawling around inside it.
“The most striking feature of the Central Plain is the ten-kilometer-wide dark band running completely around it at the halfway mark. It looks like ice, so we’ve christened it the Cylindrical Sea. Right out in the middle there’s a large oval island, about ten kilometers long and three wide, and covered with tall structures. Because it reminds us of Old Manhattan, we’ve called it New York. Yet I don’t think it’s a city; it seems more like an enormous factory or chemical processing plant.
“But there are