Science can fix everything; didn't they promise her that? Didn't she become a scientist because she believed that scientists solved problems? Survival, she reminded herself. They had to feed what was left of the population—twenty million? Ten? The government didn't publish the latest census data. They had trouble enough keeping the trains running between Alaska and Canada, and trading what remained of the oil in the former ANWR for goods and research funding. Suddenly, science wasn't a search for truth; it became a search for food and for continuing life. What could be more important than that?
When she got home, she tried her new earrings on and cried. Her tearstained eyes glanced at her hand, and she contemplated it a while—deeper dark around the fingernails and in the creases of the joints, lightening at the phalanxes, and pink at the palm. Tiny moons of her fingernails seemed to hover above the darkness of her fingers. She cried for herself and for her poor corn plants, which she could not make better. The plants whose soul was eaten away by the viruses, and nothing could restore it to them, not even viruses themselves. They died because there was nothing for them to be; she feared to continue this thought and played with her earrings instead.
The next day she came to work early and ran the labyrinth of glass corridors and elevators to the safety of her lab like a gauntlet. She wanted to be in the comfort of her equipment, in the shared misery of her plants. Before she could turn the thermocycler on, someone knocked at the door.
Willow jolted upright and fought a sudden urge to cover her face with her hands. Through the glass door, she saw the smiling face of Emari from the transposon lab down the hall.
"Come in,” Willow said.
Emari grinned and entered. “Going to the conference in Anchorage next week?"
Willow shook her head. “I have nothing to present. The dwarves wouldn't stabilize. What about you?"
"I'm going,” Emari said. “We found some freaky stuff with Mu21. It just loves that UV light. Loves it. And I think if we move to transposable mutagenesis, we might be able to dispense with viral vectors altogether."
"Trying to put me out of work?"
Emari laughed. “Of course not; we'd never lose such a good gene jockey as you. What do you care about the vector? Just make us new mutations, and our little Mu will take care of them.” She grew serious. “Besides, Andre tells me that you've had some thoughts about viruses that were ... let's say, not very flattering."
"Uh huh."
"Want to get some tea?"
"Okay. But let's go outside."
Emari glanced at the window. Heavy clouds rendered the world grey—low enough UV to venture outside for a few minutes. “Sure."
The two women strolled along one of the paths that transected the institute's garden. Initially, it was meant as an enticement for the visitors and the advertisement for the donors, showcasing all of the Institute's achievements; now, Willow and Emari exchanged a sad smile at the sight of these monstrous plants, violet and bronze, their leaves leathery, their stems bulbous, ill. There was no funding to maintain the garden, and only the ugliest and the most resilient plants persisted, UV light be damned.
The women sipped their tea tasting of grass—the best they grew in Alaska.
"Look at those colors.” Willow pointed out an especially brilliant plant, streaked in florid bronze and dark purple.
"Yeah,” Emari said. “Wild transposons are turning on. I wonder if they would do a better job than us.” She drained her cup and turned to Willow. “So what's with you and viruses?"
Willow wasn't sure if she was asking about her skin and shrugged. “Well. Human history was run by viruses. We wouldn't even be in the Americas if the Spaniards’ viruses didn't kill off the locals. They wouldn't need so many slaves, too, so there would be no African Diaspora. The influenza epidemics helped the Allies to defeat Germany in the WWI, so without it ... who knows? And if it wasn't for AIDS and Ebola, we wouldn't all fit in Alaska."
"And?"
"And it's the same with evolution, I think. How many genes were translocated by viruses? Even your transposons are just viruses without anything but the DNA."
"That's why I love them,” Emari said. “Transposon is a perfectly abstract parasite."
"Well. They are good at it, you know? I can't help but think that we're just their tools, letting them do what they do best. Bringing them wherever they want to go."
"So evolution and human history are just a massive viral conspiracy.” Emari was not laughing anymore and looked at Willow with worry in her green eyes.
Willow shrugged. “Do you really feel that in your relationship with transposons you're the one in control?"
Emari shook her head. “It's a battle, no doubt. But may I ask why you're helping them?"
"This?” Willow raised her hand. “I'm just reversing the treatment I had after I was born."
"Oh. It is quite smart, actually; I hear that melanin offers some protection against UV. Soon, everyone will be doing it."
Willow cringed. If Emari was right, soon everyone would be like Willow, the color of their skin divorced from meaning or history. It would be just an adaptive trait. Like the violet streaks on the corn.
Willow woke up in the middle of the night, her hair damp with sweat, her thoughts more lucid than ever, the skin on her hands and feet burning. She sat up and stared at the billowing of the white curtains on the windows. The answer came to her in her fevered sleep, and for a while she wasn't able to accept it.
The cancer, the dying corn, her own misery; it all happened because they had forgotten who was the master in this relationship and who was the servant. Things went bad because people decided to manipulate the viruses without understanding them. From the very first pox-infected blanket, things went wrong. Viruses did not take kindly to their rightful place being usurped.
Her legs wobbled under her as she stood and threw on some clothes. She was going to set things right, to let the viruses roam free like they were meant to, to paint their unfathomable designs in skin and leaves, without interference from human meddlers.
The Institute was empty, except for a security guard who gave her an indifferent look. No doubt, he was used to wild-haired scientists experiencing breakthroughs and running for their sequencers at any hour of the night. Willow waved at him and stumbled for the elevator.
She stopped by the lab to load up a cart with cell cultures that harbored viruses of every stripe with every imaginable corn gene inserted into them, and pushed it to the greenhouse, often stopping to wipe the sweat that ran down her face. She tried not to think about whether it was the virus inside of her that pushed her on, getting giddy at the impending freedom of its brethren ... she chased such thoughts away.
In the greenhouse, she flicked on the daylights, illuminating the experimental plants in all their sickly, tumorous nudity. If she didn't do something, they would never get it right. People would starve. People would burn to the crisp and die. They would poison what remained of the air and the water. It wasn't their fault; they were just not equipped to do the viruses’ job. She had to trust the viruses to make it better.
Willow emptied the dishes over the plants, smearing thick translucent cellular jelly over leaves and stems. She pushed apart the heavy glass panels that protected the plants from the ravages of the outside air and gulped the night and the coolness with wide-open mouth. She poured the leftover viral cultures over the plants in the garden below and threw the empty Petri dishes after them.
She waited for the sound of shattering glass, gripping the windowsill. The creases on the joints of her fingers looked pitch black and she could feel the restless shimmying and shifting of the virus in her blood. It made her hair sing like taut violin strings, it made her skin burn.
Willow had to lean against the wall as her legs grew weak. She felt no fear, only the calm assurance that the plants would flourish. And after that, she would find a way to liberate the human viruses, to let them shape the humans as they had been doing for thousands of years.
She stroked her
skin, burning, hot to the touch, almost smoldering under the viral assault. “Be still,” she whispered. “I will take good care of you."
Copyright (c) 2007 Ekaterina Sedia
[Back to Table of Contents]
THE ALTERNATE VIEW: REAL NUCLEAR FUSION ON A TABLETOP by JOHN G. CRAMER
In the December 1989 issue of Analog, I wrote an AV column entitled “Cold Fusion, Pro-fusion, and Con-fusion” that described and gave my opinions about the recently announced “discovery of cold fusion” by Stanley Pons and Martin Fleischmann. These University of Utah electrochemists claimed that by electrolyzing D2O (heavy water) on a tabletop, they had produced the nuclear fusion of deuterium (mass-2 hydrogen) nuclei inside a palladium electrode, generating lots of extra heat but no significant radiation. My column was written very early in that controversy and the dust had not completely settled, but it was clear to me at the time (and is still clear) that the reported results were an example of bad science and overblown claims.
By contrast, in this column I want to report on a well-executed experiment performed by B. Naranjo, J. K. Gimzewski, and S. Putterman (NGP) of UCLA that demonstrates the successful production of the nuclear fusion of deuterium with a relatively simple tabletop experiment. It was reported in the April 28, 2005 issue of the science journal Nature. The announcement of this breakthrough produced hardly a blip in science-based news reports, perhaps because many science reporters had previously been burned by the overblown Pons and Fleischmann affair.
* * * *
So what is d+d nuclear fusion? Let's review the process. Nuclear fusion is the primary energy source of the Sun. High temperatures and pressures near the Sun's center drive the fusion of hydrogen into helium, releasing lots of energy. Here on Earth, we would also like to use fusion as our primary energy source, but, with the exception of thermonuclear bomb explosions, we have yet to master the trick very well. One must bring two deuterium nuclei (mass-2 hydrogen containing a proton and a neutron) close enough together that they can fuse. This fusion could, in principle, form a single helium nucleus (2 protons + 2 neutrons), and a gamma ray, liberating about five million times more energy than could be obtained from any chemical reaction between two atoms.
However, there are several problems with achieving this. First, both deuteron nuclei have a positive electrical charge. When they get close, these charges repel, producing a large electrical force that pushes the nuclei apart. One must overcome this force with either high temperatures or acceleration to bring the deuterons close enough to fuse.
The second problem is that a fusion process must simultaneously obey the law of energy conservation and of momentum conservation. Because of this dual requirement, the d + d fusion reaction makes helium-3 plus a neutron or hydrogen-3 plus a proton with much higher probabilities than it makes helium-4 plus a gamma ray. Therefore, any d + d fusion reaction should be a prodigious source of fast neutrons, i.e., neutron radiation. As someone said in 1989, Stanley Pons’ own announcement refuted his claims, because if his experiment had actually worked, he would have died of neutron exposure before reaching the microphone.
On the other hand, the NGP experiment does proceed by the d+d 3He+n reaction and does make lots of neutrons. It gets the deuterons close enough to fuse by accelerating one deuteron to a kinetic energy of about 115,000 electron-volts and slamming it into another at-rest deuterium atom by using a heated 1-cm-thick ferroelectric crystal of LiTaO3 (lithium tantalate) to produce a very large electric potential (~115,000 volts).
What? A 1-cm-thick crystal producing a 115 kilovolt electric potential? That sounds like magic! Yes, I suppose it is magic in a way, the kind of quantum magic that occurs in some crystals called the ferroelectric process.
To understand it, let's first consider ferromagnetism. The atoms of the metals iron, cobalt, and nickel contain little built-in magnetic compasses, each with its own little needle with a north and a south pole, called its magnetic dipole moment. Many materials have such magnetic moments, but in the ferromagnetic materials they like to line up to form a permanent magnet, with most of the atoms pointing their little compass needles in the same direction, so that a bar of the material has a definite north magnetic pole at one end, a south magnetic pole at the other end, and a fairly strong magnetic field around the bar. This occurs because, for subtle reasons involving quantum mechanics, a ferromagnetic system with the magnetic moments of its atoms lined up has a lower net energy than does one with the magnetic moments pointing in random directions. We have now seen this quantum magic in magnets so frequently that we take it for granted and use it to stick notes and pictures to our refrigerator doors without thinking about it.
A ferroelectric crystal works the much same way. Individual molecules of the crystal have an electric dipole moment, with a net positive electric charge on one end of the molecule and a negative charge on the other end. Again, for subtle reasons involving quantum mechanics, a ferroelectric crystal with its electric moments lined up has a lower energy than one with the electric moments pointing in random directions, creating a sheet of positive charge on one end of the crystal and a sheet of negative charge on the other. This is not a new discovery. It was first described by the Greek natural philosopher Theophrastus in 314 BC, it has been studied for many years by condensed-matter physicists and chemists, and it is the basis for a commercial device that produces low-intensity X-rays.
In analogy with the poles of a permanent magnet, the ferroelectric crystal has a definite positive-charge end and negative-charge end. Under the right circumstances, particularly when it is heated (pyroelectricity), it develops a sizable electric potential between them. However, in air the electric field of a ferroelectric material is not so easy to observe because it is rapidly dissipated by polar molecules (e.g., water vapor) attracted to the surface and neutralizing the net charge. In a vacuum, however, this does not happen, and significant electric fields can be produced by the pyroelectric process as the crystal is heated.
The UCLA group placed a cylindrical 3-cm-diameter by 1-cm-thick ferroelectric lithium tantalate crystal in a vacuum vessel to which deuterium gas at a pressure of 0.7 Pa (0.0001 psi) had been admitted. The crystal was mounted with its negative end attached to a temperature-variable copper block and its positive end supporting a copper disc with a sharp tungsten spike at its center. The spike was 0.080 mm in diameter, 2.3 mm long, and had a tip radius of 100 nanometers. When the positive end of the crystal reached its maximum electric potential, the electric field near the tip of the tungsten spike was very large (greater than 25 volts per nanometer), strong enough to pull loose the electron from a deuterium atom and send the positively charged nucleus in the other direction. Thus, a beam of ionized deuterium nuclei was given an energy of up to 115,000 electron-volts and directed against a grounded target plate placed opposite the crystal. The target plate supported a sheet of deuterated polyethylene, providing deuterium atoms with which the beam of deuteron ions could collide.
The crystal was temperature-cycled, first dropping its temperature to 240 K (-33 C) using liquid nitrogen and then progressively raising the temperature with electrical heating while observing the results with neutron and X-ray counters. After 100 seconds of heating, X-rays were observed from free electrons in the gas hitting the positive copper disc and crystal. After 160 seconds the neutron signal rose above background and increased rapidly until 220 seconds, when the heater was shut off. Neutron emission then began to drop as the deuteron beam bled off charge faster than the pyroelectric current could replace it, but strong neutron emission continued until 393 seconds when a spark discharged the system.
The reported measurements show clear evidence that the nuclear reaction d+d3He+n had been produced, that the system had produced a deuteron beam ion current of 5 4.2 nA and had produced about 900 neutrons per second. Subsequent measurements at Rensselear Polytechnic Institute have confirmed the UCLA measurements. Therefore, a tabletop experiment has successfully produced controlled d+d fusion. This was accomplished usin
g well-established physical phenomena and has required no “visits from the Tooth Fairy” to make the process work.
There are some obvious improvements that could be made to the fusion demonstration configuration used by the UCLA group. First, there is no reason to attach only one sharp spike to the copper disc. As long as spikes on the disc are separated by distances greater than their length, they can operate as independent sources of deuterium ionization. Thus, one can imagine a “bed of nails” configuration using a copper disk equipped with perhaps 100 such tungsten spikes. This would in principle increase the fusion reaction rate and neutron yield by two orders of magnitude. Second, the Rensselear group has demonstrated that by using two pyroelectric crystals mounted in opposing positions with oppositely charging faces, the electric field can be doubled. For example, in the NGP configuration the deuterated target could be located on the negative face of a second pyroelectric crystal, with both crystals cooled and heated together, to produce a deuteron beam with a kinetic energy of 230 keV for the reactions, allowing the deuterons to travel further into the target and make more fusion reactions before losing too much energy to react. One could even think of stacking many crystals to achieve significantly larger potential differences. Third, if the target was made of a material loaded with tritium (mass-3 hydrogen) instead of deuterium (mass-2 hydrogen), the fusion reaction rate and neutron production rate would be about 100 times larger, and would produce neutrons that are six times more energetic (about 15 MeV instead of 2.5 MeV). We also note that by replacing the low-pressure deuterium in the vacuum vessel with low-pressure helium-3, one could produce “radiation-free” energy with the d+3He4He+p fusion reaction, which produces no neutrons and would be very easy to shield in a power-production context.
* * * *
Thus, tabletop controlled fusion is now a reality! What does that mean? Are we on the brink of the new controlled fusion age of pollution-less and virtually free energy? Should we hold off buying a new car until the fusion-powered models become available? Sorry, it's not that easy.
Analog SFF, October 2007 Page 12
