He said, I imagine youre the first Astronomer Royal to visit the Moon?
You know, I dont think any of us even left Earth before.
Flamsteed would be proud of you.
I like to think so. She sipped her coffee, and couldnt help but grimace.
He smiled. I apologize for Clavius coffee. And for the reception youve received here. We Moon-folk are an odd lot. A small society.
I was expecting a certain insularity.
But its more than that, Mikhail said. We are very self-reliantwe 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 isnt 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 wrongneutrinos, thought to be massless, actually were notand 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 anomalyjust when everybody thought it was sorted out for good.
Okay. But even though hes prickly, I get the sense that hes popular here.
Mikhail pulled his lip. I wouldnt say popular. But its well known that it was Eugenes 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 coursehe came to me at the South Pole so I could raise the alarmbut even so Eugenes warning saved a lot of lives. Thats 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 wouldnt think that a brain like Eugenes 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 didnt 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 Siobhans 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 suns 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; Im afraid youre leaving us all behind. He glared at her with a resentful intensity. But this was the heart of the matter; she needed to get this clear. Youre 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 Ive 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, dont 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 things 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 Eugenes rather terrifying glare was turned on her. But thats trivial.
Triviaclass="underline" among academics that word was a killer put-down. Roses 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
He was right, Siobhan realized uneasily. That fourth-power factor would lead to even small changes being magnified. Huge as it was, the core wasnt necessarily stable at all, and any small perturbation could disrupt it significantly.
Bud Tooke interrupted with a raised finger. I dont get it, Eugene. So what? Even if the whole core explodes, it would take megayears for the bang to work its way out to the surface.
Rose Delea grinned sourly. Dont tell me. The radiative layer is screwed too, right?
She was correct; another of Eugenes images showed it. That great tank of slow-propagating energy was flawed by a puckered scar, like a wound stitched through flesh by a bullet. And so, Siobhan realized uncomfortably, the million-year lagging around the core wouldnt work as a protective layer: any energy released in the core could be squirted straight out to space.
Eugene looked at Rose, puzzled. How did you know about the flaw?
Because this is turning out to be that kind of day.
Eugene talked on about his models of the core oscillations, and how he was hoping to run them back in time. Im intending to develop models of the inciting event of this instability, which
Never mind the past for now, Siobhan interrupted. Look forward. Show us whats to come.
Eugene seemed puzzled that the future should even be of interest compared with the deep physical mystery of the origin of this anomaly. But he obediently ran his graphic forward in time, at an accelerated pace.
Siobhan could see that the wave propagation through and around the core was complex, with multiple harmonics added to the base oscillations, and waves that were nonlinear, as the specialists would say, with energy leaking from one mode into another. But she immediately saw that there were patterns of interference, of dissipationand, more ominously, of resonance, when the energy she could so clearly see flowing around the core of the sun gathered into powerful peaks.