Which was exactly what the spaceship was doing. The most distant photographs of all had disclosed structural features in the nebula. It was not amorphous. It had form. As the Llanvabon drew nearer, indications of structure grew more distinct, and Tommy Dort had argued for a curved approach for photographic reasons. So the spaceship had come up to the nebula on a vast logarithmic curve, and Tommy had been able to take successive photographs from slightly different angles and get stereopairs which showed the nebula in three dimensions; which disclosed billowings and hollows and an actually complicated shape. In places, the nebula displayed convolutions like those of a human brain. It was into one of those hollows that the spaceship now plunged. They had been called “deeps” by analogy with crevasses in the ocean floor. And they promised to be useful.
The skipper relaxed. One of a skipper’s functions, nowadays, is to think of things to worry about, and then to worry about them. The skipper of the Llanvabon was conscientious. Only after a certain instrument remained definitely nonregistering did he ease himself back in his seat.
“It was just hardly possible,” he said heavily, “that those deeps might be nonluminous gas. But they’re empty. So we’ll be able to use overdrive as long as we’re in them.”
It was a light-year-and-a-half from the edge of the nebula to the neighborhood of the double star which was its heart. That was the problem. A nebula is a gas. It is so thin that a comet’s tail is solid by comparison, but a ship traveling on overdrive—above the speed of light—does not want to hit even a merely hard vacuum. It needs pure emptiness, such as exists between the stars. But the Llanvabon could not do much in this expanse of mist if it was limited to speeds a merely hard vacuum would permit.
The luminosity seemed to close in behind the spaceship, which slowed and slowed and slowed. The overdrive went off with the sudden pinging sensation which goes all over a person when the overdrive field is released.
Then, almost instantly, bells burst into clanging, strident uproar all through the ship. Tommy was almost deafened by the alarm bell which rang in the captain’s room before the quarter master shut it off with a flip of his hand. But other bells could be heard ringing throughout the rest of the ship, to be cut off as automatic doors closed one by one.
Tommy Dort stared at the skipper. The skipper’s hands clenched. He was up and staring over the quartermaster’s shoulder. One indicator was apparently having convulsions. Others strained to record their findings. A spot on the diffusedly bright mistiness of a bowquartering visiplate grew brighter as the automatic scanner focused on it. That was the direction of the object which had sounded collision-alarm. But the object locator itself—according to its reading, there was one solid object some eighty thousand miles away—an object of no great size. But there was another object whose distance varied from extreme range to zero, and whose size shared its impossible advance and retreat.
“Step up the scanner,” snapped the skipper.
The extra-bright spot on the scanner rolled outward, obliterating the undifferentiated image behind it. Magnification increased. But nothing appeared. Absolutely nothing. Yet the radio locator insisted that something. monstrous and invisible made lunatic dashes toward the Llanvabon, at speeds which inevitably implied collision, and then fled coyly away at the same rate.
The visiplate went up to maximum magnification. Still nothing. The skipper ground his teeth. Tommy Dort said meditatively:
“D’you know, sir, I saw something like this on a liner of the Earth-Mars run once, when we were being located by another ship. Their locator beam was the same frequency as ours, and every time it hit, it registered like something monstrous, and solid.”
“That,” said the skipper savagely, “is just what’s happening now. There’s something like a locator beam on us. We’re getting that beam and our, own echo besides. But the other ship’s invisible! Who is out here in an invisible ship with locator devices? Not men, certainly!”
He pressed the button in his sleeve communicator and snapped:
“Action stations! Man all weapons! Condition of extreme alert in all departments immediately!”
His hands closed and unclosed. He stared again at the visiplate, which showed nothing but a formless brightness.
“Not men?” Tommy Dort straightened sharply. “You mean—”
“How many solar systems in our galaxy?” demanded the skipper bitterly. “How many planets fit for life? And how many kinds of life could there be? If this ship isn’t from Earth—and it isn’t—it has a crew that isn’t human. And things that aren’t human but are up to the level of deep-space travel in their civilization could mean anything!”
The skipper’s hands were actually shaking. He would not have talked so freely before a member of his own crew, but Tommy Dort was of the observation staff. And even a skipper whose duties include worrying may sometimes need desperately to unload his worries. Sometimes, too, it helps to think aloud.
“Something like this has been talked about and speculated about for years,” he said softly. “Mathematically, it’s been an odds-on bet that somewhere in our galaxy there’d be another race with, a civilization equal to or further advanced than ours. Nobody could ever guess where or when we’d meet them. But it looks like we’ve done it now!”
Tommy’s eyes were very bright.
“D’you suppose they’ll be friendly, sir?”
The skipper glanced at the distance indicator. The phantom object still made its insane, nonexistent swoops toward and away from the Llanvabon. The secondary indication of an object at eighty thousand miles stirred ever so slightly.
“It’s moving,” he said curtly. “Heading for us. Just what we’d do if a strange spaceship appeared in our hunting grounds! Friendly? Maybe! We’re going to try to contact them. We have to. But I suspect this is the end of this expedition. Thank God for the blasters!”
The blasters are those beams of ravening destruction which take care of recalcitrant meteorites in a spaceship’s course when the deflectors can’t handle them. They are not designed as weapons, but they can serve as pretty good ones. They can go into action at five thousand miles, and draw on the entire power output of a whole ship. With automatic aim and a traverse of five degrees, a ship like the Llanvabon can come very close to blasting a hole through a small-sized asteroid which gets in its way. But not on overdrive, of course.
Tommy Dort had approached the bowquartering visiplate. Now he jerked his head around.
“Blasters, sir? What for?”
The skipper grimaced at the empty visiplate.
“Because we don’t know what they’re like and can’t take a chance! I know!” he added bitterly. “We’re going to make contacts and try to find out all we can about them—especially where they come from. I suppose we’ll try to make friends—but we haven’t much chance. We can’t trust them a fraction of an inch. We daren’t! They’ve locators. Maybe they’ve tracers better than any we have. Maybe they could trace us all the way home without our knowing it! We can’t risk a nonhuman race knowing where Earth is unless we’re sure of them! And how can we be sure? They could come to trade, of course—or they could swoop down on overdrive with a battle fleet,that could wipe us out before we knew what happened. We wouldn’t know which to expect, or when!”
Tommy’s face was startled.
“It’s all been thrashed out over and over, in theory,” said the skipper. “Nobody’s ever been able to find a sound answer, even on paper. But you know, in all their theorizing, no one considered the crazy, rank impossibility of a deep-space contact, with neither side knowing the other’s home world! But we’ve got to find an answer in fact! What are we going to do about them? Maybe these creatures will be aesthetic marvels, nice and friendly and polite—and, underneath, with the sneaking brutal ferocity of a mugger. Or maybe they’ll be crude and gruff as a farmer—and just as decent underneath. Maybe they’re something in between. But am I going to risk the possible future of the human race on a guess that it’s safe to trust them? God knows it would be worthwhile to make friends with a new civilization! It would be bound to stimulate our own, and maybe we’d gain enormously. But I can’t take chances. The one thing I won’t risk is having them know how to find Earth! Either I know they can’t follow me, or I don’t go home! And they’ll probably feel the same way!”