The inner surface was a mosaic of greens, blues, and browns—trackless desert; jungles; glaciers and vast oceans. Streaks of white clouds cast deep shadows upon the terrain. The ring rotated and brought a new feature into view— a tremendous hurricane forming over an unimaginably wide body of water.
Equations scrolled furiously across Cortana as she studied the ring. She checked and rechecked her numbers—the rotational speed of the object and its estimated mass. They didn’t quite add up. She ran through a series of passive and active scans . . . and found something.
“Captain,” Cortana said, “the object is clearly artificial. There’s a gravity field that controls the ring’s spin and keeps the atmosphere inside. At this range— and with this gear—I can’t say with one hundred percent certainty, but it appears that the ring has an oxygen- nitrogen atmosphere and Earth- normal gravity.”
“If it’s artificial, who the hell built it . . . and what in God’s name is it?”
Cortana processed that question for a full three seconds, then finally answered: “I don’t know, sir.”
Captain Keyes took out his pipe, lit it, and puffed once. He examined the curls of smoke thoughtfully. “Then we’d better find out.”