It was one of the minor annoyances of Captain’s situation that the leaner, and therefore less physically appalling, of his captives was also the nastier. “You be still,” he ordered, pointing a lean fist at Wan; his ravings had been even more nearly sense-free than the female’s. “You! Do you know what this is?”
At least the female had the sense to speak slowly. It took only a few repetitions before he understood Klara’s answer: “It is the black hole we were going to visit.”
Captain shuddered. “Yes,” he said, trying to match the unfamiliar consonants. “Exactly.” Burst was translating for the others, and he could see the tendons writhing on their limbs in shock. Captain chose his words carefully, pausing to check with the ancestral minds to make sure he had the right words:
“Listen carefully,” he said. “This is very dangerous. Long, long ago we discovered that a race of Assassins had killed off every technologically advanced civilization in the universe-at least in our own Galaxy, and in some nearby ones …”
Well, it did not go that swiftly. Captain had to repeat and repeat, a dozen times for a single word sometimes, before the blubbery creatures could seem to grasp what he was saying. Long before he was finished his throat was raw, and the rest of his crew, though they knew as well as he what perils were involved, were frankly dozing. But he didn’t stop. That chart on the screen, with its clustered energy-sinks and its quintuple warning legend, did not let him relax.
The Assassins had done their work of slaughter millennia before the Heechee appeared on the scene. At first the Heechee had thought they were simple monsters from the primeval past, no more to be feared in their time than the Heechee equivalent of a tyrannosaur.
Then they had discovered the kugelblitz.
Captain hesitated there, looking around at his crew. The next part was hard to say, for it led to an obvious conclusion. His tendons writhing, he plunged ahead:
“It was the Assassins,” he said. “They have retreated into a black hole but the particular kind of black hole that is composed of energy, not matter, for they themselves were not made of matter. They were pure energy. Inside their black hole they exist only as a sort of standing wave in an energy sea.”
By the time he had repeated it several times, in several ways, he could see that questions were forming; but the logical deduction he feared wasn’t among them. The question was from the female, and it was only:
“How can a being composed only of energy survive?”
That was easy enough to answer. The answer was “I don’t know.”
Because Robin was, quite naturally, preoccupied with other concerns, I was not then able to discuss the kugelblitz with him in as much detail as I would have wished. Its statistics were interesting. Its temperature I calculated at about three million Kelvin, but that was not worrying. It was the energy density that disturbed me. The energy density of black-body radiation goes up as the cube of the temperature-that’s the old Stefan-Bolzmann law-but the number of photons goes up linearly with the temperature, too, so effectively it’s a fourth-power increase inside the kugelblitz. At one Kelvin it’s 4.72 electron-volts per liter. At three million it’s three million to the fourth power times that-oh, say, about 382,320,000,000,000,000,000,000,000 ev/ liter. And there was a bunch of liters in that thing. What’s the importance of that? That all that energy represented organized intelligences. Assassins. A universe of them, all stored in the one kugelblitz, waiting for their plans to mature and the universe to be remade to suit them.
There were, Captain knew, theories-theories that said the Assassins had once been creatures of physical bodies but had somehow cast them off- but whether the theories had any relation to fact even the oldest of the massed minds could not say.
But it was the very difficulty of survival for beings of pure energy, Captain explained, that led to the last and worst thing about the Assassins. The universe was not hospitable to them. So they decided to change the universe. Did something to create a good deal of additional mass in the universe. Caused the expansion of the universe to reverse itself~ Holed up in their kugelblitz … and waited.
“I have heard of this missing mass often,” said the male captive eagerly. “The Dead Men when I was a child spoke of it-but they were crazy, you know.”
The female stopped him. “Why?” she demanded. “Why would they do this?”
Captain paused, bone-tired from the ordeal of trying to communicate with these dangerous primitives. Again the best answer was “I don’t know,” but there were speculations. “It is thought by the massed minds,” he said slowly, “that the physical laws of the universe were determined by random fluctuations in the distribution of matter and energy at the first moment after the Big Bang. It is possible that the Assassins intend to interfere with that process. Once they have collapsed the universe and it rebounds, they may change those basic laws-the ratio of the masses of the electron and proton, the number that relates the gravitational force to the electromagnetic-all of them-and so bring about a universe in which they could live more comfortably … but you and I could not.”
The male had been less and less able to contain himself. Now he burst out in squawking sounds, only gradually turning into intelligible words. “Ho-ho!” cried Wan, wiping away a tear. “What cowards you are! Afraid of some creatures that hide themselves in a black hole, to do something that won’t happen for billions of years! What does that matter to us?”
But the female had grasped Captain’s meaning. “Shut up, Wan,” she said, her facial muscles tightening in an almost Heechee expression. “What you’re saying is that these Assassins aren’t taking any chances. They came out once before to wipe out everybody who looked like he might be going to get civilized enough to interfere with their plan. They might do it again!”
“Exactly so!” cried Captain with pleasure. “You have said it precisely! And the danger is that you barbarians-you people,” he corrected himself, “are likely to bring them back. Using radio! Penetrating black holes! Flying all around the universe, even up to the kugelblitzes themselves!
Surely they have left monitoring systems to warn them if new technological civilizations emerge-you must very soon alert them, if you haven’t already!”
And when the prisoners had finally understood; Wan whimpering in fear, Klara white-faced and shaken; when they had been given food packets and told to rest; when the crew clustered around Captain to know what made his jaw tendons writhe like snakes, he could only say, “It is beyond belief.” To make the blubbery ones understand him had been difficult enough; for him to understand them, impossible. He said, “They say they cannot make all their fellows stop.”
“But they must,” cried White-Noise, aghast. “They are intelligent, are they not?”
“They are intelligent,” agreed Captain, “for otherwise they would not use our ships so easily. But I think they are also mad. They have no rule of law.”
“They must have law,” said Burst, unbelieving. “No society can live without law!”
“Their law is compulsion,” said Captain gloomily. “If one of them is where the agencies of enforcement cannot touch him, he may do as he pleases.”
“Then let them enforce! Let them track down every ship and make it stop!”
“You foolish White-Noise,” said Captain, shaking his head, “think about what you have said. Chase them down. Fight them. Battle them in space. Can you imagine any louder commotion than that-and can you imagine the Assassins will not hear?”
“Then what?” whispered Burst.
“Then,” said Captain, “we must reveal ourselves.” He raised his hand to still debate, and gave orders.
They were orders the crew had never thought they would hear, but they perceived Captain was right. Messages flew. In a dozen places in the Galaxy long-silent ships received their remote-controlled commands and came to life. A long dispatch was sent to the monitors near that central black hole where the Heechee lived, by now the first word of warning should have got through the Schwarzschild barrier and reinforcements should be coming out. It was a herculean task for the short-handed crew, and Twice’s absence was regretted more sorely than ever. But at last it was done, and Captain’s own ship turned on a new course for a rendezvous.
As he curled into a sleeping ball, Captain found himself smiling. It was not a joyous smile. It was the rictus of a paradox too wounding to respond to in any other way. He had feared, all through the talk with the captives, that they would come to an unwelcome conclusion: Once they knew that the Assassins had hidden themselves inside a black hole, they might easily suspect the Heechee had done the same, and so the central secret of the Heechee race would be compromised.