Recursion

“Oh.”

Herb licked his dry lips. So this was it. He gazed around at the illuminated walls of the spaceship, looked through the viewing field at the receding disk of his abused planet, and wondered sadly how it had come to this.

He thought back to the day that he had left Earth. Walking across the dew-soaked lawn beneath a cloudless blue April sky that seemed to go up forever. His spaceship had sat waiting on the grass ahead of him. Herb had paused for a moment to glance around at the beautiful spring morning. The sight of his father’s house, the green copper dome on its roof, the cream-painted stone walls and the windows reflecting the early morning sunshine. What could he find in space that couldn’t be equalled or surpassed by that morning?

Now he wondered: would things have been different if he hadn’t taken off then?

Herb didn’t know. All he knew was that in three minutes he would be jumping to almost certain death. He looked miserably around Robert’s ship again. The pale blue room, the dark viewing area…

He felt sick.

Herb’s spaceship had separated into two new ships. Two creamy white boxes that tumbled slowly through space behind them. Robert looked on, impressed.

“Almost perfectly balanced,” he whispered. “Only a fraction of a gram’s difference between the two. And only a total mass of one point seven grams lost in the process.”

Herb nodded in terrified agreement. The two ships that now floated behind looked identical to him. He would have expected no less, of course. The twin ships began to drift apart.

“What now?” asked Herb.

“One’s going back to your converted planet to replenish its mass. We’re going to board the other and make the jump into the Enemy Domain.”

“What about restoring our ship’s mass?” asked Herb frantically, hoping for a way to delay the impending jump. “It won’t be working at optimal efficiency at only half mass. What if we’re attacked? The walls will be too thin to deflect any attack.”

Robert gave a little laugh. “The thickness of the walls will make no difference when the Enemy Domain attacks. The ship may as well be made of rice paper for all the protection it will give us.”

There was a faint sigh and the floor hatch opened up. Robert gestured towards it.

“Okay, Herb, our new ship has docked. After you.”

Herb felt his stomach sink. His hand tightened around the sharp little VNM Robert had given him.

He stepped into the hatchway. Robert followed.

The replication was very good. The ship was identical to the original, right down to the copy of The Blue Magnolia, now coming to its conclusion in the entertainment tank. Herb ran his hand across the white leather of the sofa. It felt just as soft, just as cool. Did the ship carry spare leather, he wondered?

He could almost believe that the replication hadn’t taken place, that he was back on his original ship, but of course there was no original ship now. It had split into two identical copies, each of half the original mass. A display had lit up on one wall informing him of the fact. If he cared to, he could examine the status of the fission right down to the subsystems level. Herb didn’t care.

Robert was at work meanwhile altering the ship’s interior, opening viewing fields in all four walls and the ceiling. Smaller viewing fields opened in the floor, interspersed with screens across which multicolored lines and patterns scrolled. Status screens. Herb found himself standing in a viewing field, a silver puddle of light shimmering around his ankles.

“Sit on that sofa,” said Robert, pointing to the one opposite. “I’m arranging it so we can see everything from the conversation area.”

Herb stepped out of the puddle and sat down opposite Robert.

A sudden jerk pushed him back into his seat. It was followed by two more that knocked him over to the left.

“Sorry. I’m just trying to get the gravity field adjusted. We barely got enough exotic matter in the division to enable the warp jump. There’s not much left over to maintain gravity.” Robert grimaced. “If the enemy gets us in a steep enough gravity gradient, we’ll be smeared across the inside of this ship like butter.”

“Thanks,” said Herb, turning pale.

“Actually, that won’t happen,” Robert said happily. “I forgot. The hull is so weak after the separation, the ship will crumple along with us. It will be like sending a bag of blood through a mangle.”

Herb moaned.

Robert paused in his work and looked at him.

“Don’t worry, Herb. There’s nothing to worry about. We’re going to win. Just remember, the EA AI is far more intelligent than anything in the Enemy Domain. It’s not about the Enemy’s greater strength, it’s about the intelligent application of force. Ask any swordsman: the point beats the edge every time.”

“I’m not comforted,” said Herb.

“Well, I tried.” Robert sighed.

Herb was shaken around on the sofa by another series of violent jerks. Throughout the sudden shuddering motion he could sense a steady acceleration, usually hidden by the internal gravity field.

A mapping of the Enemy Domain suddenly appeared above their heads, a cloud of silver and rose with significant features picked out in gold and blue. Robert gazed up at it and nodded in satisfaction. It vanished and Robert turned and looked at several of the viewing fields he had opened up around the ship, checking that everything was okay.

“Have you got your VNM?” he asked Herb, who wordlessly held it up. Tiny scarlet drops of his blood shimmered on the edge of the sharp metal points that had cut their way through the thick linen cloth in which the machine was wrapped. Herb hadn’t even felt any pain. The ship’s gravity cut out again and he felt himself pushed back against the seat. Herb wondered why it was necessary to travel quite so fast. What was the point when they were about to make a jump? They would only have to slow down again at the other end.

“Can you think of anything we’ve forgotten?” Robert asked, his gaze still traveling from viewing field to viewing field.

“No,” said Herb. He wished he could think of something.

“Okay, here we go, then.”

When he was younger, Herb had thought he knew all about superluminal travel. He was now just old enough to admit that he didn’t. The AIs insisted that the methods used were beyond human intelligence, and no human had yet been able to contradict them. Herb did understand the basic principles, however.

He knew that special relativity dictated that it was impossible to travel faster than light in an area of flat space-time; however, he also knew that general relativity placed no restrictions on two regions of flat space-time moving apart at greater than light speed. The equations describing a warp field that could move a region of flat space-time faster than light had been derived long ago, at the end of the twentieth century, before even the first AIs had appeared. Human intelligence had shown that exotic matter was required in order for the fields to exist.

It was fair to say that contemporary AIs insisted that the superluminal travel they provided was far removed from those “trivial” equations, but they did agree on two particulars.

First, the warp drive required exotic matter.

Second, it involved moving a region of flat space-time around the universe.

Herb was in such a region now. And the ship’s velocity within that flat region must be considerable.

Herb wondered why.

They inserted themselves back into regular space-time. The forward-viewing areas lit up with brilliant white light. Those to the rear of the cabin darkened.

“Atomic explosion,” Robert said in some surprise. “Their detection systems are better than I expected, as are their reactions. If we were at rest relative to the warp, we’d have been right at the heart of that. As it is, we’ve