Once at the Stanford Linear Accelerator, a famous story went, an off-site user who was a professor elsewhere was watching fresh data emerge in a late-night experiment. He jumped to the conclusion that he was seeing a new particle. Right away he started talking about setting up a new group to study the effect and asked a postdoc to come work with him as soon as the group was formed. The postdoc kept quiet when a few days later the professor called a big meeting of all collaborators of the in-house group, plus users, and dramatically showed the data, claiming that he—not “we,” the postdoc noted—had discovered a new particle. The data didn’t look sound to some. More noise than signal, the standard cut said. Within a few weeks the professor was out of the collaboration, gone, flushed from the field. Overclaiming was a permissible flaw, the familiar vice of ego, but beating a drum with no parade behind you betrayed poor judgment. A big mouth was more dangerous than anything but a bald error.
She was going to keep hers well shut until she figured out what was going on. Midmorning, students working nearby, a whole day beckoning. Nerves a bit jittery, but work would cure that.
Alicia turned away from the magnet poles. What next? The problem with the unknown was its lack of road signs. Yesterday they had tried the diamond-tipped drill and gotten nowhere. She started taking the drill apart on a workbench, thinking about using a laser, when she noticed a glint from the drill tip. It shone brightly in the lab’s fluorescent glow.
Under a low-power microscope the diamond tip seemed fresh. Had its contact rubbed away the slight layer of oxidation all metals develop?
She tried a higher-power microscope borrowed from Walter Bron’s lab in another building. The sphere had no discernible structure at that level of magnification. No cracks, abrasions, flaws. What was it?
She felt a tingling, curiously pleasurable: her “curiosity reflex,” she had called it in high school, when she had first glimpsed the serene certainties of physics, starkly contrasting with the world’s raw hubbub.
The drill bit had made a high keening sound when pressed against the sphere. It had scraped the diamond tips clean.
When in doubt, do the obvious. She arranged calipers and carefully measured the radius of the sphere. Getting everything centered properly, she brushed against the sphere, the first time she had touched it. The surface felt slightly warm, smooth. Not cool, as she had intuitively expected; metals feel cool, even if they are at room temperature, because they conduct heat readily, and skin reacts sensitively to heat loss rates. She stroked it a few times while making the measurements, then averaged her numbers: 37.8 cm. plus or minus about 0.3 cm. A small bowling ball.
She thought awhile about ways to weigh it. If she knew the magnet’s mass, she could weigh the assembly and subtract—but she didn’t. A direct measurement would require easing off the magnetic field and lowering in onto a scale. She felt uneasy at the idea. What if the magnetic restraint were somehow important to its structure? Her intuition was to leave matters as they were, even if working on the thing was a bit harder in a magnetic field. She did not like the picture of losing control of it in the lab.
She frowned. That ozone smell. A damned big clue, but pointing at what? When in doubt, get some numbers.
She went up to the chemistry department and looked up a simple test for ozone concentration. Oxygen was two atoms, she remembered, and with enough energy added it became three: ozone. It was heavier than air, so if the sphere were giving it off, the stuff would drift to the lab floor. Silent electrical discharges made it, and the Chemical Rubber Handbook said that ultraviolet radiation around 250 nanometers could, too. That was an energy of 4 electron Volts, equivalent to a temperature of about 40,000 degrees.
Was the sphere emitting radiation up in the ultraviolet? She couldn’t see anything. It took a moment to walk around the bay switching off the high fluorescents and local spot lamps. After her eyes had adjusted, she peered between the magnet poles. The human eye could see over an enormous range of sensitivity, better than photodetectors, but it could be deluded, also.
A glow there? Try looking at it out of the corner of the eye. The desire to find something could provoke what she called “wantum mechanics,” fishing a result out of nothing but noise. To prevent that she turned around in the pitch darkness and looked again. Where was it? There? She put her hands out and felt a lab bench. No, she wasn’t fully rotated. The faint light she thought she saw had been in the wrong place. She turned her head but saw nothing. Try again. Nothing. After more fruitless trials, she quit.
Perhaps try looking in a darkened room with some high-sensitivity photodetectors? That demanded quartz lenses…
Maybe later. Right now, try something simple.
One of the atmospheric testing labs in the geophysics department had a compact, computerized meter just sitting in their cabinets which measured ozone, for atmospheric pollution studies. She quickly wangled her way through a postdoc, then had to properly consult the professor in charge, of course, and he cheerfully let her swipe it for a short while. He even came by the lab, wondering what she was doing with such an ordinary instrument when she worked at ultra-high energies. She was so jumpy she at first tried to stand between him and the U-magnet, then realized he couldn’t make anything out through the close-packed instruments, anyway. Seldom can a non-specialist divine the function of gear. “Just looking for a funny source,” she said, trying to sound relaxed.
She spent the middle of the day taking readings at varying distances from the sphere, neatly penciling them in her lab book. It was a sweet device, user-friendly. The ozone concentration fit an inverse square relation pretty well, just as though it were being created at the sphere’s surface and then diffusing outward.
She sat and frowned at the thing while her graduate students worked on the Core Assembly in the other half of the high echoing bay. She had told them she didn’t want to be disturbed and went over every hour to see if they needed help with the excruciatingly tedious work on the replacement Core Element.
Should she try to cut it with a laser? That required quite a powerful laser, a big job to even get it in here and set up. Also, attention-getting. Who had one? Toborek? Bron? No, too much trouble and risk.
How about asking a metallurgist? Not much help there if it wasn’t metal, and something in her gut now told her that it wasn’t. Also, another way to launch rumors.
Just to be doing something, she fetched the low-power laser they had for general use in the bay. She set up some simple optics and trained the laser on the sphere. Then she made the resulting beam fall on a simple white screen, which she made out of the plastic backing from a Core Assembly shipping crate.
She had some trouble lining everything up right and getting the screen between the magnet’s poles, close to the sphere. When she reflected the beam from the surface at a steep angle, it came off nice and tight, a single ruby spot a millimeter across, scintillant on the screen.
Then she shifted the angle so that the beam struck the very right-hand edge of the sphere, just skimming the surface. The spot spread into an ellipse several centimeters long.
“Ummmm?” she murmured, puzzled. She fooled with the setup for awhile, but there was no way she could be wrong.
That should not be. The curved edge should scatter the beam into a smear, but not nearly so broad as the ellipse that hung on the screen a few centimeters from the sphere. To get a broad ellipse meant that the sphere refracted the beam, not just reflected it.
She twisted her mouth, not liking this conclusion. It was as though the steady laser beam went into the sphere a bit, then got refracted back out.
She thought of another test. She edged a wooden ruler into the laser beam from the left and watched the elliptical spot. A dark border crept into the right side on the screen.
“The left side is refracted most,” she whispered to herself.
Light coming in on the left edge of the tiny laser beam went farther… into the sphere?… and so suffered more refraction, so that it came out on th
e right hand of the spot. The refraction reversed left with right.
So this thing reflected light, all right, but it refracted, too, proportional to how far the light went in. But that made no sense. In? The sphere looked like a hard reflecting metal surface. As though light bounced off one single layer. But this refraction result plainly said that light penetrated to different layers of differing refractive strengths.
Her head hurt, not from the ideas but from staring at the laser beam. Her mind refused to budge any further. Brad Douglas called to her from the far end of the bay, where students were laboriously assembling the new Core Element. Something about a part he could not find.
Somewhat gratefully, she went to help him. When in enough doubt, let your subconscious work on the problem.
4
At the end of her Physics 3-B lecture she happened to look down at the textbook. While the students emptied out of the deep bowl lecture hall, she paged through it idly. She used this moment, rather than struggling through the inadequate doorways, as an implicit invitation to ask questions; some, particularly the Asians, were terminally shy about coming to office hours.
Her approach in lecture was to give her own slant on the material, assuming the class had read the textbook to get a different flavor. This always rankled a faction, she knew, who wanted lectures that combed through the material in exactly the same way they had read it, salted with heavy hints about the exam. She much preferred students who cared for the physics itself, of course; her job, then, to show them some of the sublimely simple beauty in it.
The textbook pages were dotted with black-and-white photos of Physics Greats, typically in portrait pose, head and shoulders only, wearing jackets and ties, gazing off in lofty meditation. Only Richard Feynman and Einstein came across casually, Feynman playing bongos and Einstein wild-haired and sad-eyed in a sweatshirt. Great men—she did not think, Great white men—abstracted out of their time and place and assumptions. That too was an assumption, of course: that physics rose above the stormy swamp of culture.
Well, maybe. Some of her first love of physics had come from that hope: that humanity could loft above the dark plain of incessant strife and passion, glimpse a serene beauty hovering beyond the veil of tribe and language. Such visions came to the great, soaring intellects, who passed them down to those struggling below.
Alicia had no illusions that she was going to be a lofty monolith like Einstein or Faraday or Fermi. There came a time in the lives of physicists when they realized that they would be spear carriers, not prima donnas, in the grand opera of science. But she felt a delicious tension as she left the lecture hall and headed straight for the lab. Let department tasks and paper grading wait; she had gotten into physics for exactly this pulse-quickening sense of Being on the Chase.
No students had stopped to ask a question; they rushed off to memorize. With a decisive snap she shut the textbook, gathered up her viewgraphs, and went off to her lab.
Zak had been following her instructions from yesterday. He had carted in a gaggle of photodetectors rounded up from hers and other labs. Nobody had a lot of instrumentation in these days of ever-dwindling funding. Borrowing was common. She reviewed the gear, noticing that it had been bought on grants from the Air Force, NSF, Navy, Department of Commerce, and NASA. Did these agencies know to what diverse uses their dollars went? Sure. They just looked the other way. Only senators and simpletons thought science took place in neatly drawn boxes.
She and Zak finished getting the photodetectors set up and linked to computers. First they would study the sphere’s properties in light it reflected. Then they would work in the dark and look for emission. Rather than move the magnet and sphere, they wanted to hood the magnet with light-shielding cloth and then kill the lights for good measure. Her graduate students usually worked in the afternoon, after class, so mornings were best. They were nearly ready to start when her lab phone rang. She answered, despite a strong temptation to ignore it. Her secretary knew better than to disturb her here except for something important.
“Alicia? Hugh Alcott, Brookhaven?”
“Oh. Ah, yes.” A sudden, keen apprehension.
“We’ve been reviewing the accident? And were wondering if you had anything to add.”
“Uh, like what?”
“Anything about the debris?”
“I don’t think so.”
“Well, I’d like a description from you of the whole thing, the incident, in writing.”
“I thought you recorded the safety meeting.”
“Well, we’ve got to dot the i’s on this thing, you see.”
“Why?”
He paused, as if surprised. She wished they were on one of those Net systems that carried a visual still, refreshed every five seconds. But then he could see her, too, and she was not sure what her expression might give away. Good grief, he could even have seen the magnet behind her.
“To be sure it doesn’t happen on your next uranium run.”
“Oh, sure.” She had completely forgotten that she had a run penciled in for half a year from now. Could they get the Core Element ready in time?
“Then you’ll e-mail it to me?”
“That might take awhile. I’m coming up on finals here—”
“Well, I’d kinda like to see it pretty soon.”
“Okay. I’ll do what I can.”
They danced around it a little more, then Alcott finally hung up. She closed her eyes and reviewed the whole conversation, holding the phone and listening to the dial tone so that Zak wouldn’t get a look at her face before she composed herself. It seemed pretty ordinary, a bureaucrat covering his ass with paperwork. Nothing more. So why was her heart thudding?
She went back to help Zak finish hooking everything up.
“Where shall we start?”
She clicked on some illuminating lamps. “Look for some spectral lines in reflected light.”
“Iron? We could look for spectral lines.”
“Sure,” she said and rattled off two line frequencies in an easy-to-see range. She didn’t think this thing was steel, but they had to start somewhere.
It took half an hour to be sure that there were no iron lines. In another hour they failed to find any other lines, except those already present in the illuminating lamps. When Zak wondered what that meant, she exploited Professorial Mystique, a technique she had observed often. “Ummm,” she murmured mysteriously and started setting up for the studies in the dark.
It was nearing noon, but they hooded the magnet and the photosensors and doused the lights. Carefully they patrolled through the spectrum displayed on a computer screen, looking for emission from the sphere. There were the usual goofs and errors, quickly corrected. Light leaking through a doorjamb reflected into one of the photodetectors and they had to mask for that.
After a long while, Zak said, “We’re getting photons…”
“How much?” She checked the hood to be sure nothing was leaking into the magnet area.
“Very, very few. Right at the edge of detectability.”
She checked the ‘scope traces. “I don’t see a line.”
“There isn’t any.”
“No lines? There must be.”
“There aren’t.”
“Something wrong with our setup, then,” she said firmly.
So they went over the entire arrangement again. It was straightforward and she was sure they would find a loose cable or shuttered input somewhere. They did not. So they looked again and still did not. Finally she sighed and said, “Okay, maybe the spectrum is right. But how can it be?”
Zak looked at her blankly. “I don’t know.”
The light was distributed all across the spectrum. Atoms emit precise frequencies, corresponding to the jumps that electrons make between their quantized energy levels. In a solid the atom-atom binding interactions smeared these lines somewhat, but not enough to yield what they saw. This dim glow was spread everywhere, not concentrated at all.
“That’s crazy
,” Alicia said.
“Maybe we’ll bring the lines up out of the noise if we accumulate over a longer time,” Zak said.
If they simply added up all the light—in camera language, keeping the shutter open for awhile—then errors would tend to cancel themselves out and they would see the persistent radiation.
“Fair enough.” Alicia was pleased. Zak was a quick, absolutely competent student, always thinking one step beyond, able to adapt. A natural. Professors educate those who are capable, but they treasure the students who go beyond that level, who make working with them exciting, not a job at all.
They let the optical-processing system work on the emitted light for twenty minutes. Alicia felt both elation and worry as they waited, checking the system as it counted photons of light over the full width of its spectrum. Elation, that the sphere did seem to be giving off some light. Very, very faint, but it was there. Worry, though, because possibly this entire result was just a mistake. Maybe their makeshift rig, set up in a big bay not designed for this sort of sensitive spectral work at all, was letting in an unsuspected source of light. Well, they would have to repeat it all, of course. Nobody trusted a delicate measurement on the basis of one trial.
“Let’s have a look,” she said when she could restrain her curiosity no longer.
The digital readout took a moment to compile and then wrote itself in a blue curve on the screen. They both reacted at the same moment. “Huh?” said Zak. Alicia drew in a quick breath, mouth gaping until she remembered to close it.
“Looks a lot like a blackbody spectrum,” Zak said.
“It does indeed.” The smooth curve peaked and fell away in the classic slope known for a century. Any dark object—the ideal blackbody—radiated such a spectrum; as it heated up, the peak shifted to the right, to higher frequencies. “No lines, for sure.” Alicia read the horizontal frequency axis and scribbled on a pad. “It’s radiating very faintly, all right… but at an equivalent temperature of over 40,000 degrees.”
COSM Page 7
