Eugene had a distracted air, and he seemed to have trouble making eye contact. But he was startlingly good looking, better even than the images had suggested, with the perfect skin and open, symmetrical face of a synth-star singer. Siobhan felt her crusty heart skip a beat. And from the glances that Mikhail occasionally cast his way, it seemed that it wasn’t just women who were drawn to Eugene’s looks.
Bud, acting as chair, stood beside her. “Before we start, let me just say one thing,” he began. “Astronauts have a proud history in solar studies. It goes back to the Skylab guys who, in Earth orbit in 1973, operated an imaging spectrograph built for them by Harvard. Today we’re continuing that tradition. But we’re not just talking about science. Today we’re being asked for our help. As the commander of Clavius Base I consider it an honor to have Professor McGorran here—an honor that we on the Moon are seen as fit to be the focus of the response to this problem. Professor.” He nodded to Siobhan and sat down.
After that pep talk, not entirely appropriate, Siobhan glanced around the table. She caught just one friendly eye, a sympathetic half smile from Mikhail Martynov. Follow that.
“Good morning. I expect to do more listening than talking today, but I’d like to make some introductory remarks. My name is—”
“We know who you are.” The speaker was evidently one of the geologists, a stocky, big-armed woman with a square face. Her glare was about the most hostile in the room.
“Then you have me at a disadvantage, Doctor—”
“Professor. Professor Rose Delea.” She had a broad Australian accent. Siobhan had been briefed; Rose was an expert on the emplacement by sunlight of helium-3 in the lunar regolith. This helium isotope, a fuel for fusion reactors, was the Moon’s best economic prospect, and so Rose was a weighty figure here. “All I want to know is when you’re going to leave so I can get back to some real work. And I want to know the reason for all this secrecy. Since June 9 outgoing comms has been restricted, some areas of Thales’s databases and other information stores have been proscribed—”
“I know.”
“This is the Moon, Professor McGorran. If you hadn’t noticed, we’re all a long way from home and our families. Links to Earth are essential for our psychological well-being, not to mention our physical safety. And if you don’t want morale to fall farther—”
Siobhan held up her hand, a gesture of quiet command. To her relief, Rose fell silent. “I quite agree.” So she did. Secrecy didn’t come instinctively to her any more than to these Moon-folk, Siobhan suspected; openness was an essential component of the endless conversation that underpinned good science. She said, “The security blackout is difficult for all concerned, and would be unacceptable—in normal times. But these are not normal times. Please bear with me.
“I’m standing before you today as an emissary of both the British Prime Minister and the Prime Minister of the Eurasian Union. When I get home I’ll also be expected to brief other world leaders, including President Alvarez of the United States. And what they want to know is what to expect of the sun.”
She was met by mostly baffled stares. Her briefings by various world-weary politicians’ aides had warned her to expect a certain insularity up here on the Moon, where the Earth could seem a long way away, and not very important. So she had prepared a show-and-tell. “Thales, please . . .”
She gave them a five minute summary, in images, graphics, and words, of the devastating impact of June 9 on the Earth. This was watched in somber silence.
At the end she said, “And that’s the reason I’m here, Professor Delea. I need some answers—we all do. What’s wrong with the sun? Is June 9 going to hit us again? Can we expect something less—or worse? On the Moon—in this room, in fact—you have some of humankind’s top solar scientists. And the one person who made an accurate prediction of June 9 itself.”
Eugene didn’t react; his gaze unfocused, it was as if he was barely aware of the others around him.
Mikhail said dryly, “And of course the ease of controlling information from the Moon is purely coincidental.”
Siobhan frowned. “We have to take security seriously, sir. The governments really have no idea of what they’re facing yet. Until they do, information, unfortunately, must be managed. A panic could be vastly damaging in itself.”
Rose subsided, but she was glowering, and Siobhan hoped beyond hope that she hadn’t already made an enemy.
As brightly as she could she said, “Let’s start by making sure we’re all singing from the same hymn sheet. Doctor Martynov, I wonder if you’d be good enough to tell a mere cosmologist how the sun is supposed to work.”
“It will be a pleasure.” With a showman’s sense of theater Mikhail stood and made his way to the front of the room.
“All cosmologists know that the sun is fueled by fusion fire. What most cosmologists don’t know is that only the innermost heart of the sun is a fusion reactor. The rest of it is special effects . . .” Mikhail’s Russian accent was movie-actor thick, but quite compelling.
During her training, Siobhan had of course studied the sun. She had learned that the sun, like all stars, is simple in principle, but as the nearest star the sun had been scrutinized in minute detail. The detail, it turned out, was rather overwhelmingly complex and still little understood, even after centuries of study. But it was that detailed behavior that now seemed to be endangering humankind.
The sun is a ball of gas, mostly hydrogen, more than a million kilometers wide—that is, as wide as a hundred Earths strung side by side, and as massive as a million Earths. The source of its vast energy output is its core, a star within a star where, in complicated chains of reactions, swarming nuclei of hydrogen fuse to helium and other heavier elements.
The fusion energy must pass out through the body of the sun from the hot core to the cold sink of space, driven by temperature differences as surely as a head of pressure drives water through a pipe. But the core is swaddled by a thick belt of turgid gas called the “radiative zone,” opaque as a brick wall, through which the inner heat passes in the form of X-rays. In the next layer out, the “convective zone,” the densities have lessened to the point where the sun’s material can boil, like a pan heated from below. Here the core heat continues its journey to space by powering huge convective spouts, each many times taller than Earth, ascending at not much more than walking pace. Above the convective zone lies the visible surface of the sun, the photosphere, the source of sunlight and sunspots. And just as the meniscus of a boiling pan of water will organize itself into cells, so the sun bubbles with granules, constantly changing, tiling the photosphere like a Roman mosaic.
So immense and compressed are these layers that the sun is all but opaque to its own radiation; a given photon’s worth of energy takes millions of years to struggle from core to surface.
Once released from its cage of gases, the core energy, in the form of light, races away at lightspeed as if with relief, spreading with distance as it travels. At the distance of the Earth, eight light-minutes from the photosphere, sunlight still delivers about a kilowatt of power per square meter—and even at a distance of light-years the sunlight is bright enough for any eyes there to see it.
As well as the light it emits, the sun breathes a constant stream of hot plasma into the faces of its circling children. This “solar wind” is a complex, turbulent breeze. At certain frequencies of light can be seen dark patches on the sun’s surface—“coronal holes,” regions of magnetic anomaly, like flaws in the sun itself—from which pour higher-energy streams of solar wind. The turning sun sprays these streams around the solar system in spiral washes, like an immense lawn sprinkler.
Mikhail said, “We watch out for those sprinkler streams. Every time the planet runs into one we get problems, as the Earth and its magnetosphere are battered by high-energy particles.”
Still more problems are caused for the Earth by the sun’s occasional irregularities. Mikhail said, “You have coronal mass ejections—like the monster
that hit us on June 9—large-scale outpourings of plasma flung at us from the sun’s surface. And then you have flares. These detonations on the sun’s surface, powered by magnetic flaws, are the largest explosions in the modern-day solar system, each amounting to the blast of billions of nuclear weapons. Flares bombard us with radiation from gammas to radio waves. Sometimes they are followed up by what we call ‘solar proton events’—cascades of charged particles.”
The restless sun follows an eleven-year “solar cycle,” at the peak of which sunspots swarm and flares erupt with much more vigor than at its minimum. Mikhail sketched the accepted mechanism behind the solar cycle. A “meridional flow” of plasma over the sun’s surface from equator to poles carries the relics of sunspots north and south. At the poles the cooling material sinks down into the body of the sun as far as the base of the convective zone, and then migrates back toward the equator. But the magnetic scars left by sunspots linger on through this cycle, ghosts that seed the next generation of active regions.
Mikhail described the complicated relationship of sun, Earth, and humanity.
Even in historical times the sun’s variability has affected the Earth’s climate. For more than seventy years, from around 1640 to 1710, very few sunspots were observed on the sun’s face—and the Earth was plunged into what the climatologists call the “Little Ice Age.” Europe suffered severe winters and cool summers; at the peak of it, in 1690, London children ice-skated on the Thames.
In the electronic age, a growing dependence on high technology made humans much more vulnerable to even mild solar tantrums. In April 1984 a flare knocked out communications on Air Force One; President Reagan, over the mid-Pacific, was left incommunicado for two hours. Before June 9 the most intense storm on record had occurred in September 1859; that one had melted telegraph wires.
“We actually came close to that again in 2003,” Mikhail said. “The sun suffered two eruptions in successive days, aimed right at the Earth. We were saved from more severe effects only by a chance alignment of magnetic fields.”
Rose Delea was getting restless. “All these phenomena are well known.”
Mikhail said, “Yes, we think we are getting a handle on measuring the effects of these different solar glitches—and predicting them, though that’s still more an art than a science . . .” He put up a slide of three “space weather scales” that the current Space Weather Service had inherited from the old American Space Environment Center, and had elaborated on since. “You can see we describe three types of problem for Earth: geomagnetic storms, solar radiation storms, and radio blackouts. Each type is calibrated with these scales, from one to five—one being minor, and five being severe.”
Siobhan nodded. “And June 9—”
“June 9 was principally an outcome of a coronal mass ejection, and would be measured by our G-scale, our geomagnetic-storm scale.”
“And its rating?”
“Off the scale. June 9 was unprecedented. But the irony is that the event was better predicted than any solar glitch in history, thanks to Doctor Mangles.” He glanced at Eugene.
But Eugene, as distracted as ever, didn’t react to the cue; he seemed barely aware that the rest of the group existed.
There was an awkward silence. Bud called for a break.
You had to fetch your own coffee, it turned out; there were no spare hands to fetch and carry. And there were no digestive biscuits, not one on the whole damn Moon.
A line quickly formed at the coffee spigot at the back of the room. But Mikhail, near the front of the queue, picked up two plastic beakers of coffee and tentatively approached Siobhan, who accepted a beaker gratefully. Mikhail’s face was lugubrious and crumpled, and his voice was warm and rich; Siobhan liked him instinctively.
He said, “I imagine you’re the first Astronomer Royal to visit the Moon?”
“You know, I don’t think any of us even left Earth before.”
“Flamsteed would be proud of you.”
“I like to think so.” She sipped her coffee, and couldn’t help but grimace.
He smiled. “I apologize for Clavius coffee. And for the reception you’ve received here. We Moon-folk are an odd lot. A small society.”
“I was expecting a certain insularity.”
“But it’s more than that,” Mikhail said. “We are very self-reliant—we have to be. But that breeds a certain indifference to outsiders, and sometimes resentment. This meeting is all about Eugene, of course. And Eugene is—”
“Special?”
He smiled. “Something like that. His personality is clearly difficult. And his social situation isn’t helped by his choice of discipline. For the last generation of solar physicists, neutrinos were, for a long time, something of an embarrassment.”
“Ah. The ‘neutrino anomaly.’ ” When it had first been studied closely, the flood of neutrinos detected coming from the core of the sun was significantly less than had been predicted by then-current models of particle physics. It had turned out that the physics was wrong—neutrinos, thought to be massless, actually were not—and when that was put right in the theoretical models, the “anomaly” went away.
“You know how it is in science,” Mikhail said gloomily. “Fashions come and they go. My area of work, this messy solar weather with its plasma storms and tangled-up magnetic fields, has never been fashionable. But after the business of the anomaly, solar neutrino studies were definitely not a sexy subject area. And then Eugene annoyed everybody by detecting yet another sort of neutrino anomaly—just when everybody thought it was sorted out for good.”
“Okay. But even though he’s prickly, I get the sense that he’s popular here.”
Mikhail pulled his lip. “I wouldn’t say popular. But it’s well known that it was Eugene’s work that gave us our only early warning of the June 9 event. Nobody believed a word until the event was actually in progress, of course—he came to me at the South Pole so I could raise the alarm—but even so Eugene’s warning saved a lot of lives. That’s made him something of a folk hero, you see, among us exiles from Earth. So when an outsider like yourself shows up, no matter how highly qualified—”
“I understand.” She eyed him and said carefully, “You just wouldn’t think that a brain like Eugene’s could reside behind such a face.”
Mikhail looked at Eugene with undisguised longing. “But I think his face, his body, is his curse. Everybody assumes he must be no more than an ‘airhead jock,’ as my American colleagues say. Nobody takes him seriously. Even I find his looks—”
“Distracting?” She smiled. “Welcome to the club, Mikhail.”
Mikhail said edgily, “But it is what goes on inside that beautiful head that is so disturbing.”
Bud reconvened the session.
13: Neutrinos
When Eugene Mangles spoke, every eye turned his way curiously. His accent was small-town American, Siobhan thought, and he sounded like a teen, younger than his midtwenties; his looks didn’t fit what he had to say.
And his presentation about the anomalies he had discovered at the heart of the sun, while no doubt technically accurate, was anything but lucid.
Siobhan actually knew a lot about neutrinos. There are three known ways to make neutrinos: with fusion processes in the heart of a star like the sun, by turning a nuclear reactor on and off, and in the Big Bang that gave birth to the universe itself, the titanic event whose large-scale consequences were Siobhan’s own subject matter. What makes neutrinos so useful to solar astronomers is that matter is all but transparent to them. And so neutrinos provide a unique way of studying the sun’s inner structure, including the fusing core, a place from which even light struggles to escape.
That much was clear. But as Eugene displayed screen-filling equations and graphs in several dimensions, and as he talked ever more rapidly, Siobhan wondered how he had ever got through his doctorate oral exam.
Eventually she broke in. “Eugene. Slow down, please; I’m afraid you’re leaving us all behind.” He gla
red at her with a resentful intensity. But this was the heart of the matter; she needed to get this clear. “You’re showing us results of your neutrino measurements.”
“Yes, yes. Of the three flavors of neutrinos, which are interrelated by—”
She waved that away. “You are seeing oscillations in the neutrino flow.”
“Yes.”
“And that in turn,” she pressed on doggedly, “reflects oscillations in the fusion processes in the core.”
“Precisely,” he said sarcastically. “The neutrino flux tracks back to local changes in core temperature and pressure. Which in turn I’ve been able to model as dynamic oscillations of the core as a whole.” He displayed dense mathematics, which Siobhan recognized as nonlinear wave equations. “As you can see—”
“Eugene,” Mikhail said gently, “don’t you have some kind of picture of this?”
Eugene looked surprised by the question. “Of course I do.” He tapped his softscreen and brought up an image of a sphere. It was covered by a kind of gridwork, like lines of longitude and latitude. And the pattern faded and pulsed rhythmically.
Bud Tooke whistled. “And this is the core of the sun? Our sun? The damn thing’s ringing like a bell.”
Rose Delea folded her arms and pulled her face. “Forgive a mere geologist for being skeptical, but the core of a star is a pretty massive bloody thing. How can it suddenly start to oscillate?”
Now Eugene’s rather terrifying glare was turned on her. “But that’s trivial.”
Trivial: among academics that word was a killer put-down. Rose’s face was a mask of hostility.
Siobhan said quickly, “Take it step by step, Eugene.”
He said, “It goes back to the work of Cowling in the 1930s. Cowling showed that the rate of nuclear energy generation in the core is dependent on the fourth power of temperature. Which makes conditions in the core of the sun extremely sensitive to temperature changes . . .”