Charles Stross - Singularity Sky

“Commmmmander. Welcome. Please be seated.”

Commodore Bauer walked toward the desk and took the indicated chair.

“And how is your father these days? It’s — it’s a while since I saw him.”

“He’s very well sir.” At least as well as he could be, considering he died four years ago . Bauer looked at his superior sadly. Once the sharpest saber in the New Republic’s arsenal, Rear Admiral Kurtz was rusting at a terrifying rate: they must already be planning the funeral. He still had periods of lucidity, sometimes quite extended ones, but forcing him to go on this expedition — and no officer could realistically refuse a royal commission and expect to continue to hold his post— was positively cruel; surely His Majesty must have known about his state? “May I ask why you summoned me, sir?”

“Ah — ah — ah, yes.” The Admiral jerked as if someone had just administered an electric shock to him.

Suddenly his expression tightened. “I must apologize, Commodore: I have too many vague moments. I wanted to discuss the flisposition of the — I mean, the disposition — the fleet. Obviously you will be in day-to-day command of the task force, and in overall tactical command once it arrives at Rochard’s World. The matter of planning, however, is one to which I feel I can make a contribution.” A wan smile flitted across his face. “Do you agree with this?”

“Ah, yes, sir.” Bauer nodded, slightly encouraged. The grand old man might be drifting into senility, but he was still razor-sharp during his better moments: if he was willing to sit back and let Bauer do most of the driving, perhaps things might work out. (As long as he remembered who Bauer was, the commodore reminded himself.) They’d worked together before: Bauer had been a junior lieutenant under captain Kurtz during the Invasion of Thermidor, and had a keen respect for his intellect, not to mention his dogged refusal to back down in the face of heavy opposition. “I was led to believe that the General Staff Directorate has some unusual plans for lifting the siege; is this what you have in mind?”

“Yes.” Admiral Kurtz pointed at a red leather folder lying on his desk. “Contingency Omega. I had a ha-hand in the first paper, ten years ago, but I fear younger minds will have to refine it into a plan of attack.”

“Contingency Omega.” Bauer paused. “Wasn’t that shelved, because of, ah, legal concerns?”

“Yes.” Kurtz nodded. “But only as a plan of att-att-attack. We are not allowed to fly closed timelike paths — use faster-than-light travel to arrive before war breaks out. Leads to all— all — sorts of bother.

Neighbors say God doesn’t like it. Blithering nonsense if you ask me. But we’ve already been attacked.

They came to us. So we can arrive in our own past, but after the attack began: I must confess, I think it is a bit of a pathetic excuse, but there we are. Contingency Omega it is.”

“Oh.” Bauer reached toward the red folder. “May I?”

“Cer-certainly.”

The Commodore began to read.

Accelerating to speeds faster than light was, of course, impossible. General relativity had made that clear enough back in the twentieth century. However, since then a number of ways of circumventing the speed limit had turned up; by now, there were at least six different known methods of moving mass or information from A to B without going through c .

A couple of these techniques relied on quantum trickery, strange hacks involving Bose-Einstein condensates to flip bits in quantum dots separated by light-years; as with the causal channel, the entangled dots had to be pulled apart at slower-than-light speeds, making them fine for communication but useless for transporting bodies. Some of them — like the Eschaton’s wormholes — were inexplicable, relying on principles no human physicist had yet discovered. But two of them were viable propulsion systems for spaceships; the Linde-Alcubierre expansion reciprocal, and the jump drive. The former set up a wave of expansion and contraction in the space behind and in front of the ship: it was peerlessly elegant, and more than somewhat dangerous — a spacecraft trying to navigate through the dense manifold of space-time ran the risk of being blown apart by a stray dust grain.

The jump drive was, to say the least, more reliable, barring a few quirks. A spaceship equipped with it would accelerate out from the nearest star’s gravity well. Identifying a point of equipotential flat space-time near the target star, the ship would light up the drive field generator, and the entire spaceship could then tunnel between the two points without ever actually being between them. (Assuming, of course, that the target star was more or less in the same place and the same state that it appeared to be when the starship lit off its drive field — if it wasn’t, nobody would ever see that ship again.) But the jump drive had huge problems for the military. For one thing, it only worked in flat space-time, a very long way out from stars or planets, which meant you had to arrive some way out, which in turn meant that anyone you were attacking could see you coming. For another thing, it didn’t have a very long range. The farther you tried to jump, the higher the probability that conditions at your destination point weren’t what you were expecting, creating more work for the loss adjusters. Most seriously, it created a tunnel between equipotential points in space-time. Miscalculate a jump and you could find yourself in the absolute past, relative to both your starting point and the destination. You might not know it until you went home, but you’d just violated causality. And the Eschaton had a serious problem with people who did that .

This was why Contingency Omega was one of the more sensitive documents in the New Republican Navy’s war plan library. Contingency Omega discussed possible ways and means of using causality violation — time travel within the preferred reference frame — for strategic advantage. Rochard’s World was a good forty light-years from New Austria; normally that meant five to eight jumps, a fairly serious journey lasting three or four weeks. Now, in time of war, the direct approach zones from New Austria could be presumed to be under guard. Any attack fleet would have to jump around the Queen’s Head Nebula, an effectively impassable cloud within which three or four protostellar objects were forming. And to exercise Contingency Omega — delicately balancing their arrival time against the receipt of the first distress signal from Rochard’s World, so that no absolute causality violation would take place but their arrival would take their enemies by surprise — well, that would add even more jumps, taking them deep into their own future light cone before looping back into the past, just inside the spacelike event horizon.

It was, Bauer realized, going to be the longest-range military operation in the history of the New Republic. And — God help him — it was his job to make sure it worked.

Burya Rubenstein whacked on the crude log table with a worn-out felt boot. “Silence!” he yelled.

Nobody paid any attention; annoyed, he pulled out the compact pistol the trade machine had fabricated for him and fired into the ceiling. It only buzzed quietly, but the resulting fall of plaster dust got everybody’s attention. In the midst of all the choking and coughing, he barked, “Committee will come to order!”

“Why should we?” demanded a heckler at the back of the packed beer hall.

“Because if you don’t shut up and let me talk, you’ll have to answer to Politovsky and his dragoons. The worst I’ll do to you is shoot you — if the Duke gets his hands on you, you might have to work for a living!” Laughter. “ His living. What we’ve got here is an unprecedented opportunity to cast off the shackles of economic slavery that bind us to soil and factory, and bring about an age of enlightened social mobility in which we are free to better ourselves, contribute to the common good, and learn to work smarter and live faster. But, comrades, the forces of reaction are ruthless and vigilant; even now a Navy shuttle is ferrying soldiers to Outer Chelm, which they plan to take and turn into a strongpoint against us.” Oleg Timoshevski stood up with an impressive whining and clanking. “No worries! We’ll smash ‘em!” He waved his left arm in the air, and his fist morphed into the unmistakable shape of a gun launcher.