But before it had traveled more than a few hundred meters, the ball of distortion swelled up, burst silently, and dissipated.
There was a rustle of movement in the corvette, a collective sigh of disappointment.
Darc clapped Nilis on the back. “Scratch another run. Never mind, Commissary. We’re not done yet.”
“Indeed not.”
Torec said to Pirius, “Timing is everything. The implosion in the center is what we’re trying to design. If the amplitude is large enough, you get nonlinearity — a shock wave, its profile distorting as it travels, what the techs call a ’classical scalar wave.’ I think we’ve got the amplitudes right, but not the timing. If the waves don’t converge right at the center, they just pass through each other harmlessly.”
Pirius said, “And if the timing is right — what’s supposed to happen?”
Torec stared at him, the first time she’d looked at him directly since he had got here. “You were on Callisto, and you don’t know?”
Pirius said helplessly, “I just did my job there.”
“This is a design from the Occupation era. It’s a black-hole cannon, Pirius.” She smiled faintly. “Can you believe that? We’re making a cannon to fire black holes at the Xeelee. And you know what else? It was designed by Friends. Friends, just like Enduring Hope!”
Pirius, stunned, stared at the battered test rig. The techs and drones were already going back to work.
Nilis asked Pirius to spend some time with him.
They sat together in Nilis’s cabin. It was clear to Pirius that the Commissary wanted something. But Nilis was still guilty about how Pirius had been “used” on Callisto, and he seemed to want to make it up to him by talking to him.
He said his “Callisto weapon” did indeed date from the time of the Qax Occupation. Pirius was amazed that the Friends of Wigner, in his day an illegal fringe cult out on Arches, had roots that deep.
Back then the Friends had been a group of rebels on Earth. During the early phase of the Occupation, the control of the Qax had been relatively light — and remarkably enough, the Friends had been able to assemble a whole spacecraft, equipped with black-hole cannons, under the noses of Earth’s occupiers.
The Friends had known that a wormhole bridge to the deeper past was soon to be opened; spanning fifteen centuries, this audacious stunt had been set up by none other than Michael Poole. When the bridge opened, the Friends hurled themselves and their ship into the past. Ignoring the humans of Poole’s time, they had set to work preparing their battery of black holes — but their purpose was not to use their cannon as weapons. Their target was Jupiter. In the guts of the gas giant these grenades of twisted spacetime would collide and merge, each collision sending out pulses of gravitational waves. By programming this sequence, the Friends hoped to shape the collapse of Jupiter, and so sculpt the final black hole that would result.
“So that was what happened to Jupiter,” Pirius said.
“Yes. Quite a monument!”
“But if they could make black-hole cannons, if they could go back in time, why not just fly out to the Qax home world and wipe them out?”
Nilis smiled. “Spoken like a true pragmatist! But the Friends’ objective was more philosophical…”
The first Friends of Wigner had taken their name from an ancient philosopher who had pondered the mysteries of quantum physics. Beneath the world perceived by humans was a scaffolding of uncertainty. Quantum functions pervaded space, each a description of the probability governing a particle or system; it was only when an observation was made that a particle could be pinned down to a particular place, or to a definite speed.
“But this ancient philosopher, Wigner, took that logic a step further,” Nilis said. “Any observer is herself a quantum object — everything is, we all are — and therefore herself subject to quantum uncertainty. You need a second observer to make her real, and thence to make her observation real. If Wigner is the first observer, his friend is the second.”
Pirius thought that over. “But what about the friends quantum function? That isn’t made definite until a third observer makes an observation of her.”
“You have it,” said Nilis approvingly. “And then you need a fourth, and a fifth.”
Pirius’s head was swimming with infinities. “But no matter how many observers you have, how many friends of Wigner you line up, you always need one more. So nothing can be real.”
“This was called the paradox of Wigner’s friends,” Nilis said. “But the Friends believed they had a resolution.”
The chains of unresolved quantum states will build on and on, growing like flowers, extending into the future. At last the great chains of quantum functions would finally merge at the last boundary of the universe, at timelike infinity.
“And there, argued the Friends, will reside the Ultimate Observer, the last sentient being of all. All quantum functions, all world lines, must terminate in the Observer — for otherwise, she would not be the last. The Observer will make a single climactic Observation—”
“And the chains of observations will collapse.”
“History will be made real at last, but only at its very end.”
Pirius said, “But I don’t see how this was going to help the Friends get rid of the Qax.”
The Friends had come to believe that the Ultimate Observer might not be a passive eye, but that this final being might have a choice: that she might be able to exert an influence on how the chains of quantum functions were collapsed, on which cosmic history out of the many possible was selected.
“And if a being has such power,” Nilis said, “perhaps she can be lobbied. And that was what the Friends intended to do. They were going to send the Ultimate Observer a message.”
“How? With Jupiter?”
“Singularities themselves have structure, you know. The singularity at the heart of the Jupiter black hole was to be shaped, and loaded with information. It would be a plea to the Ultimate Observer. The Friends wanted the Observer to select her chosen history to favor humanity — in particular, to pick out a causal line that would not include the Qax Occupation.”
Pirius thought that over, and laughed, wondering. “That’s astonishing.”
Nilis said, “It’s a terribly nihilistic philosophy — don’t you think? Just like their modern intellectual descendants, the Friends actually seem to have believed that they, their memories, their whole lives would be wiped out of existence when the Ultimate Observer makes her choice and some optimal timeline is plucked out of the quantum tangle. The Friends were not just escaping the Qax, Ensign. Perhaps they were escaping from themselves.”
Pirius wasn’t convinced. He thought of Enduring Hope, back in the Core; if you were stuck in the middle of an endless war, the notion of an end-of-time arbiter who would one day delete all the pain from the world was a comforting idea.
But he had believed it was myth. He hadn’t known that this airy nonsense about a cleansing at the end of the universe might actually have some physics in it. It was a spooky thought.
“Of course their scheme was overcomplicated, and it didn’t work,” Nilis said. “The Friends didn’t even manage to make their black hole properly, let alone send their plea to the end of time. They managed to destroy Jupiter, though.”
The Qax responded to the treachery of the Friends with devastating force. No longer would their rule be light; no longer could human cultural artifacts be used to camouflage rebellion. The Extirpation began: human history would be deleted, human minds wiped clean, even the fossils in the ground would be pulverized. The Qax intended that humans would never pose a threat to the Qax again. They came close to succeeding.