Saturday, May 6, 2000 10:00 AM

Douglas Freebairn awoke and had the feeling that there was something he didn't want to remember.

He carefully sat up and looked around, shielding his eyes with his hands. He was on the couch in his cluttered office. A short Asian man with dyed green hair sat at a desk across from him.

"Eric. What are you doing here?"

"Catching up on grading. I'm about five weeks behind and my electromagnetism class is threatening to mutiny. Anyway, we have the meeting this afternoon."

Doug glaned up at the calendar and groaned. Circled in red were the words 'Thesis Review.' Professor Rosen wanted to review the status of his grad students and no one was going to enjoy the process.

"Oh," Eric said. "There was a message from Melissa on the machine when I got here. She said you could talk it over when she got back Monday."

"Lord," Doug said, remembering. "We had a bit of a fight last night at the airport, right before she left," Doug said. "I suggested that maybe she shouldn't take the job in Atlanta. It was stupid, but I won't get my degree for another six months."

"Six months if you're lucky. Last I heard, your work isn't going any better than mine is."

Doug couldn't deny it. He had been going in circles for the last few months. The new variant of general relativity had seemed promising at first, but recently several serious problems had come up. Professor Rosen had a lot invested in the approach and had made it obvious that a new thesis would have to be very impressive.

"Yeah, I should get some work done," Doug said. "I can at least have a list of problems ready for the meeting."


Saturday May 6, 2000, 4:30 PM

The meeting was even worse than Doug had expected. Both grad students had been throughly chewed out and warned that they had better start showing results.

Doug had wandered around campus afterwords, depressed and angry. With Melissa gone for the weekend he had nothing else to do and found himself back at the office.

Eric tossed a journal at him as he sat down. "Check it out, another improvement on the Alcubierre warp metric."

"How useful is it?"

"It gets the amount of negative energy-mass needed down to a few nanograms."

First proposed in 1994, the Alcubierre metric was an application of general relativity that allowed for superluminal travel. It was only possible given engineering capabilities that would make the Ringworld look like a weekend project, but modifications had slowly made it more practical.

"This is pretty clever," he said after skimming the article.

"Too bad we don't have more time to play around with stuff like that," Eric said.

Doug shoved it into a pile of unread articles and opened the folder containing the work done before the meeting. A feeling of deja vu struck him as he stared at the pages before him.

"Eric, come look at this," he said as he pulled the article back out of the stack. "Tell me you don't see a correlation between our work and the new warp metric."

It only took a few extra lines of transformations to make the resemblance complete. Eric was leaning over his shoulder by the time he was done.

"I just did it this morning," Doug said. "I was looking for ways our variant diverged from the standard model, testing simple experimental setups."

"So you know how to create this geometry?"

"I could do it in a few hours. I didn't even recognize it as a warp bubble until I made those changes."

"It isn't a warp bubble though. Not with this metric. Look at these terms here--that isn't a spatial displacement."

Doug blinked and realized Eric was right. It was temporal.

"Want to build a time machine?"


Sunday May 7, 2000, 1:00 PM

The spinning bit slowly made its final pass, leaving behind a surface smooth to within one thousandth of an inch. Doug waited patiently for it to clear the piece before turning off the mill. He couldn't resist spending the time the time for the extra precision, even though the device wouldn't need it.

He removed the piece from the vice and tested the fit. It would hold one of twelve capacitors around an area of negative energy. The amount of negative energy was low enough to be supplied with a Casimir device--two parallel conducting plates a small distance apart. Doug wasn't sure exactly how much precision was needed, but the equations were very forgiving. The placement of the capacitors relative to the Casimir plates was not as critical as the timing of pulses sent through the capacitors.

All of the arms fit together well, though there was no way to hide the fact that it had been designed hastily over breakfast. Satisfied, Doug signed out with the shop master and took the device upstairs.

There was a heavy smell of solder in the office when Doug entered. While he had been building the physical frame, Eric had been working on the electronics and the program to control the pulses.

"I've almost finished programming the sequence you worked out," Eric said while typing. "It would have gone a lot faster, but I had to characterize these capacitors first."

"Great. The framework is ready."

"Go ahead and attach the electronics. I don't need them for testing anymore."

The electronics were very simple, just a power supply, high speed transistors, the twelve capacitors and the connection to Eric's computer. It still ended up being a rat's nest of wire, despite Doug's best efforts to keep it orderly.

Waiting for Eric to finish the code, Doug went over the equations once more. He had spent half the night pooring over them, looking for flaws. The setup was so trivial that he couldn't believe they were the first to discover it. He hadn't found any flaws but still wondered if they weren't wasting their time.

"I'm ready here," Eric said.

Doug made a final survey of the device. The Casimir plates looked fine, and the capacitors were properly placed.

"Okay. Warp factor nine, Mr. Sulu."

Eric hit ENTER with a flourish and both turned to watch. A complex and non-repeating pattern of pulses were being generated. The change in mass-energy was creating a miniscule standing wave in spacetime. In terms of gravity, it had less effect than the proverbial butterfly in China.

Doug tried to visualize the process. Each wave pattern would give way to another, slightly more complicated one. If their new model was correct, the patterns would already be radically different from the predictions made by standard relativity. The slight amount of negative energy would act as a focus, allowing the patterns to build to a crescendo. Twelve separate waves would converge, and a small amount of spacetime would be pinched off. This balloon was what Doug had originally mistaken for a warp bubble, and it should happen right about....



Sunday May 7, 2000, 11:00 AM

Doug walked back into the office only a few minutes after he had left. Eric was still drawing schematics.

"None of the shop masters are going to be in today, so I can't build the frame until tomorrow," Doug said.

Eric looked up, pushing blue hair aside. He said, "I can at least get the electronics and programming done."

Doug sat down and rubbed his eyes. He had spent most of the night looking for flaws in the metric and had only been able to get a few hours of sleep. The new model seemed solid, and it felt right, but he was still disturbed by how easy it all was.

"After you crashed last night," Eric said, "I was playing with the equations and I couldn't see how to set the duration of travel. Once a warp starts, how do we stop it?"

"Hrm. The balloon is held open by the negative mass. But the balloon is only possible with the special conditions inside the warp, which propels it backwards through time. So if we can stop the warp then the balloon pops."

"Alcubierre suggested some kind of external device to catch a spatial warp bubble." Eric said as he plugged in the soldering iron.

"That could work. We could only go back to the time when the first catcher was created, though."

"Better than continuing on back to the beginning of time," Eric said.

Doug said, "Let's see... The only way for the warp to collapse would be if the energy was somehow dissipated. Something inside the balloon could do that."

"The interior of the balloon won't experience time passing during transit, so it would be pretty hard to time the flight that way," Eric said. He tested the soldering iron with a finger and quickly pulled it away.

"So the energy has to dissipate externally ... gravity waves! The warp expends the energy in the creation of gravity waves as it moves backwards through time. Just like two orbiting neutron stars, but backwards."

"They can't be very large waves. The total mass-energy of the warp is only slightly more than that of the contents of the balloon."

"They don't have to be," Doug said. "The energy needed to create and sustain the warp is already tiny. Otherwise we'd never be able to do it."

A small plume of smoke rose from the board Eric was working on. He said, "We should be able to figure out the rate of energy lost in these ripples then, right?"

"Sure, it's a well-understood process. The minimum amount of energy needed to create a warp gives us about ... just a second," Doug said as he scribbled in the margins of an article. After a few minutes he grabbed Eric's calculator.

"2.66x10^7 seconds or a bit under 11 months," he said. "Unless we find an even easier way to create the warp, that is the minimum distance into the past we can go. Beyond that, energy increases linearly with travel distance, at the rate of about 2.8 years per kilojoule."

Eric put down the soldering iron and said, "Let's not be greedy. A year will be plenty for the trial run."


Monday May 8, 2000, 3:00 PM

Doug watched the mill make a slow finishing pass and wished Professor Rosen would allow him to bill construction charges to the project budget. Without it he was forced to scrounge for spare stock and wasn't able to turn the construction over to one of the department's professional machinists. Two years previously he had been interested in machining but had since grown impatient with the process.

A quick test fit convinced Doug that the frame would serve its purpose, even if the workmanship was lacking. "Horse shoes, hand-grenades and spacetime warps," he muttered as he signed out of the shop.

The electronics and programming were finished and waiting for him when he returned to the office. Eric had apparently been bored the previous night after Doug went home, for the wiring and computer interface was put together neatly in a project box. The control program even had a graphical interface.

"Very slick," Doug said. "Shall we try it out?"

Eric snapped the capacitors into place and sat back at the computer.

"I'm ready when you are," he said.

"Okay. Warp factor nine, Mr. Sulu."

Eric clicked the GO button and both turned to watch. The LEDs on the project box flashed in an apparently random pattern, faster and faster, until human eyes could only see a continuous, half-strength glow.

Doug looked back and forth between the device and the computer screen, watching the countdown. He tried to imagine what was happening to spacetime inside the sphere of the twelve capacitors. Going over the metric again that morning, he had been struck with the elegance of the warp construction. The powers employed were trivial on any useful scale, yet the proper application would warp spacetime more than a hunk of neutronium. It was only at the very last instant that this happened, a process Doug visualized as the inflation of a balloon. A section of spacetime would bulge out, a little over a cubic centimeter inside, but connected to the rest of the universe through a neck a small fraction the width of a proton. The same process would also create a wave pushing the balloon into the past....



Sunday May 7, 2000, 1:30 PM

Eric muttered as the device failed to do anything for the fifth time in a row.

A short circuit during the first try had melted three of the capacitors. The second time the control code had crashed immediately.

"I told you to start writing that earlier," Doug said.

The third and fourth tries had only completed half of the cycle of pulses due to loop condition bugs.

"Hey, you know as well as I do that no program is ever bug free," Eric said.

"It doesn't have to be perfect, it just has to work. Once."

The program had run to completion on the fifth try, but the pulses had been in the wrong order for the last ten seconds of the test.

"Here it is," Eric said. "I was referencing the wrong array--stupid mistake. Restarting again."

Despite Eric's reassurances, Doug was beginning to wonder if the device was ever going to work. Even if the new metric was correct, the tolerances for creating the warp could be too high. A janitor had been convinced to let him into the closed machine shop, but he had rushed the job.

He looked up at the clock. The complete cycle took 49 seconds. A spherical chunk of the device should disappear at the end of that time, if it worked....

It did.


Saturday May 6, 2000, 8:00 AM

Douglas Freebairn awoke and smiled. The weight that had been hanging over him for months was gone. At some point during the night he had decided what he was going to do.

He was going to move with Melissa to Atlanta. Maybe he would look for a good grad program there, but not immediately. A long break from academia was in order. Whatever he did, he never wanted to deal with Professor Rosen or his pet theories ever again.

He rolled over to face her. She looked so peaceful sleeping that he decided to let her wake up on her own before telling her. Everything would be so much simpler this way.