The Lost Worlds of 2001

28. Jupiter V
Moving more and more slowly as she approached the far point of her ellipse, Discovery soared past the orbits of Ganymede and Callisto-but they were out of range on the other side of Jupiter. The ship began to fall back, cutting again across their orbits, as well as those of Europa and Io. She was about to make her first approach to the closest and in some ways oddest of all the satellites, tiny Jupiter V.

Only seventy thousand miles above the turbulent Jovian cloudscape, and completing each orbit in less than twelve hours, Jupiter V is the nearest thing to a natural synchronous satellite in the whole Solar System. For as Jupiter revolves in about ten hours, V stands almost still in its sky, drifting very slowly indeed from east to west.

It was not easy to observe Jupiter V. The tiny moonlet, only a hundred miles in diameter, was so close to Jupiter that it spent much of its time eclipsed in the planet's enormous cone of shadow. And even when it was in the sunlight, it moved so rapidly that it was hard to find and to keep in the field of view.

The fly-by on the morning of that second Joveday was not very favorable, the satellite was twenty thousand miles away, and visible only for about ten minutes. There was time for nothing more than a quick look through the telescopes, while the cameras snapped a few hundred shots of the rapidly vanishing little world.

The detailed examination of the photos would take several hours; after a while the endless repetition of impact craters, fractured rocks, and occasional patches of frozen gas produced something close to boredom. But no one could tear himself away from the screen; and at last, after more than half the stored images had been scanned, patience was rewarded.

The crucial sequence had been taken with a telephoto lens, just as Jupiter V was emerging from shadow. At one moment there was a black screen; then, magically, a thin crescent suddenly materialized, as the little moon came out of eclipse.

Kimball was the first to spot the curious oval patch near the terminator. He froze the picture, and zoomed in for full magnification. As he did so, there were simultaneous gasps from all his colleagues.

Part of the side facing Jupiter had been sheared off flat, as if by a cosmic bulldozer, leaving a perfectly circular plateau several miles across. At its center was a clear-cut, sharply defined rectangle, about five times as long as it was wide, and pitch-black. At first glance it seemed to be a solid object; then they realized that they were staring into shadow; this was an enormous hole or slot, wide enough to engulf Discovery, and extending deep into the heart of Jupiter V. It was at least a quarter of a mile in length, and perhaps a hundred yards wide.

Time and geology could play some odd tricks with a world; but this was not one of them.

It was an unusually quiet and subdued group that gathered in the artificial gravity of the carousel for the luxury of coffee that could actually be drunk from cups, not squirted from plastic bulbs.

The wonder and the excitement of the discovery had already passed, to be replaced by more somber feelings. What until now had been only a possibility-and, to tell the truth, rather a remote one-had suddenly become an awesome reality. That pyramid on the Moon had been astonishing, but it was only a tiny thing. This was something altogether different-a whole world with a slice carved off, just as one may behead an egg with a knife.

"We're up against a technology," said Bowman soberly, "that makes us look like children building sandcastles on the beach."

"Well," answered Kaminski, "we suspected that from the beginning. Now the big question is-are they still here?"

Jupiter V looked utterly lifeless, but an entire civilization could exist, miles below the surface, at the bottom of that rectangular chasm. The creatures who put TMA-1 on the Moon, three million years ago, could still be going about their mysterious business.

Perhaps they had already observed Discovery, and knew all about this mission. They might be totally uninterested in the primitive spacecraft orbiting at their threshold; or they might be biding their time.