DYNAMICS

Grant buried himself in his new job in Muzorawa’s lab. To his happy surprise he found himself becoming truly fascinated by the fluid dynamics of Jupiter’s ocean.

Muzorawa had constructed a computer model of the planet-girdling ocean, based on data from the probes they had sent below the clouds. It was at best a set of rough approximations. Grant was determined to refine them and generate a true picture of how that vast ammonia-laced sea actually behaved.

They worked together in the fluid dynamics lab. Grant thought it was slightly ridiculous to call the cramped little compartment a laboratory. There was no real experimental work going on. The only equipment there was a desktop-size hypersonic wind tunnel, a small shock tube—which looked like nothing more than a narrow length of stainless steel pipe—and a two-meter-tall transparent tank that served as a cloud simulator. There was nothing in the lab that could simulate the pressures and temperatures of the Jovian ocean. Actually, there was no laboratory apparatus in the solar system that could come close to simulating Jovian conditions. So they worked with computer simulations, instead: electronic approximations to reality, programs that accepted what little they knew and played it back to them.

GIGO, Grant thought. Garbage in, garbage out. On outdated computers, at that. Equations were no substitute for real data.

“This research would make a good doctoral thesis,” Muzorawa told him one day as they sat side by side at the computer desk.

“Doctoral thesis?” Grant echoed.

The Sudanese cocked his head slightly, as if thinking about the matter. At last he replied, “Yes, if you don’t mind switching your subject to planetary astrophysics instead of stellar.”

Grant mulled the idea. I could put my time here to good use, he thought. Instead of wasting the four years I could come out of this with a doctorate … and then go on to what I want to do after I get a university post.

“You would have to do all the course work, naturally,” Muzorawa went on in his deliberate, considered manner. “We can get the necessary materials sent from my department at Cairo. I can provide the supervision for it and—”

Grant’s eyes widened. “You’re on the faculty at Cairo?”

“In the physics department,” Muzorawa answered matter-of-factly. “Professor of fluid dynamics.”

“That’s the oldest university in the world,” Grant marveled.

Muzorawa smiled slowly. “Yes, true. Al-Azhar was founded in the tenth century by the Ismali Fatimids. It was co-opted into the University of Cairo somewhat later.” His smile broadened. “The physics department is a comparatively new addition.”

“But what are you doing here if you’ve got a full professorship at Cairo?”

Muzorawa seemed almost surprised by Grant’s question. “I am here to study Jupiter’s interior. It’s the greatest problem in fluid dynamics that is accessible to direct observation.”

“You’re here voluntarily?”

The black man nodded gravely. “I intend to remain here as long as I can. Jupiter’s ocean is the kind of problem that can take a lifetime and more.”

Grant could only shake his head in awe. This is my mentor, he thought with pride. He’s going to be my thesis advisor. It didn’t occur to Grant to wonder about the sanity of a man who willingly chose to live in an orbiting station that never got closer to Earth than six hundred million kilometers.

That night, for the first time in months, Grant sent genuinely happy messages to Marjorie and his parents. He hadn’t heard from his wife in more than a week, but he knew she was busy. She’d looked tired in her last message, weary and apprehensive. Is she ill? He wondered. Is she hiding something from me? Does she still love me?

He wondered about that. How can you stay in love with someone when you’re separated for six years, millions of kilometers apart? He was struggling to keep thoughts of Lane O’Hara out of his conscious mind, out of his dreams, even. Marjorie was surrounded by handsome young military officers and university graduates on their Public Service tours of duty: dozens of them, hundreds of them.

Still, he had good news to tell her for the first time since he’d shipped off Earth, and he kept smiling all through his message to her. It wasn’t until the computer was off for the night and all the lights in his room were turned down and he was alone in bed in the darkness that his fears about Marjorie warped his face into a pained mask of misery. He tried to pray, but the words felt empty, useless.

As the weeks passed, Muzorawa spent more and more of his time training for the coming crewed mission, less and less on the fluid dynamics problem.

“I’m afraid it’s going to be mostly on your shoulders,” Muzorawa told Grant.

“I can handle it.”

“I’m sorry to lay all this work on you,” Muzorawa went on, staring at the graph Grant had put on the wall screen.

“You can’t be in two places at one time,” Grant said.

“Still … I wanted to get this work in better shape before handing it off to you.”

“You’ve done the lion’s share,” Grant assured him. “Setting up the basic equations and all.”

Muzorawa nodded, but his face showed that he was not satisfied with the situation.

Grant was. For the first time since leaving Earth he had some real work to do. A challenge. It wasn’t stellar astrophysics, but it was almost as good. Nobody understood how Jupiter’s interior worked. Nobody! It was unexplored territory and Grant had the opportunity to blaze a trail through the unknown. He intended to make the best of it.

He’d been surprised, at first, when he found that Muzorawa’s fluid dynamics “group” consisted of the Sudanese alone.

“I thought Tamiko worked with you,” Grant had said.

“She did, studying the clouds, mainly,” Muzorawa replied. “But she was reassigned to the problem of Europa’s ocean.”

There had been two other fluid dynamicists, Muzorawa told him.

“Lucy Denova was a fine scientist,” he recalled, “with a first-rate mind. But the instant her tour of duty here ended she fled back to Selene. She’s teaching at the university there now. She still checks in with me now and then.” He chuckled wryly. “But she wants no part of this station. Not at all. She prefers her home on the Moon.”

Grant couldn’t blame her, especially if she had a position on a tenure track at Lunar U.

“And who was your other assistant?” he asked.

“Not an assistant, my friend. He was Dr. Wo himself.”

“He’s a fluid dynamicist?”

“He was, before he was elevated to the directorship. Even so, we worked together quite a lot—until …” Muzorawa hesitated.

“The accident,” Grant finished for him.

“You know about that.”

“A little.”

“A little knowledge can be a dangerous thing,” Muzorawa misquoted.

“Then I ought to get more knowledge,” said Grant.

Muzorawa didn’t argue the point. Neither did he add to Grant’s knowledge of the accident.

The fluid dynamics problem he faced, Grant quickly learned, was that they were trying to study conditions that had never been experienced before. With meager data, at that. Hundred of automated probes had been sent into the unmeasured deeps of the Jovian ocean, but the data they returned were nothing more than a series of pinpricks in a sea of ignorance ten times wider than the whole Earth.

Squeezed relentlessly by Jupiter’s massive gravity, the thick, turbulent Jovian atmosphere is compressed into liquid some seventy thousand kilometers below the visible cloud tops: a strange and unknown ocean, water heavily laced with ammonia and sulfur compounds. Yet the ocean’s temperature is far below the Earth-normal freezing point; under Jupiter’s merciless pressure, the water liquefies despite its frigid temperature. With increasing depth, though, the sea becomes increasingly warmer, heated by the energy flow from the planet’s seething interior.

That ocean is at least five thousand kilometers deep, Grant saw. More than five hundred times deeper than the deepest trench in any ocean on Earth.

And that was barely scratching the surface of gigantic Jupiter. For the first time, Grant began to understand how truly immense the planet was. The numbers didn’t even begin to tell the story; they couldn’t. Jupiter was just too mind-numbingly big for mere numbers.

An ocean more than ten times wider than Earth and five hundred times deeper, yet it is nothing more than a thin onion-skin layer on the planet’s titanic bulk. Below that ocean lies another sea, an immense brain-boggling sea of liquefied molecular hydrogen almost sixty thousand kilometers deep. Nearly eight times deeper than the whole Earth’s diameter!

And below that the pressure builds more and more, millions of times normal atmospheric pressure, compressing the hydrogen into solid metal, sending the temperature soaring to tens of thousands of degrees. There might be another ocean deep below those thousands of kilometers of metallic hydrogen, an ocean of liquid helium. On Earth, helium liquefies only a few degrees above absolute zero. Yet deep within Jupiter’s interior, helium becomes liquefied despite the ferocious temperatures at the planet’s core because all that incredible pressure squeezing down from above doesn’t give its atoms room enough to go into the gaseous state.

At the planet’s very heart lies a solid rocky core, at least five times larger than Earth, seething with the appalling heat generated by the inexorable contraction of the stupendous mass of material pressing down to its center. For more than four billion years Jupiter’s immense gravitational power has been squeezing the planet slowly, relentlessly, steadily, converting gravitational energy into heat, raising the temperature of that rocky core to thirty thousand degrees, spawning the heat flow that warms the planet from within. That hot, rocky core is the original protoplanet seed from the solar system’s primeval time, the nucleus around which those awesome layers of hydrogen and helium and ammonia, methane, sulfur compounds—and water—have wrapped themselves.

Jupiter’s core was far beyond any physical probe. Grant had to be satisfied with equations that estimated what it must be like. But that onion-skin ocean of water, that was his domain now. He was determined to learn its secrets, to probe its depths, to resolve its mysteries.

Grant’s task was to learn as much as he could about that huge ocean. The first crewed mission had failed disastrously because they had been unprepared for the conditions to be found down there. Grant drove himself fiercely to make certain that the next human mission into Jupiter’s ocean would not end the same way.

There were currents in that sea, swift vicious currents that tore through the planet-girdling ocean, ferocious jet streams racing endlessly. With the heat flowing from deep below, the Jovian ocean pulsed and throbbed in constant turbulent motion. Storms raced across its surface and roiled the sea with the energy of a million hurricanes.

Muzorawa spent very little time in the lab now; almost his every waking hour was taken by his training for the probe mission. The Sudanese physicist dropped in to the fluid dynamics lab now and then, but for the most part Grant worked alone, struggling with the attempt to map out the major global jet-stream patterns. At first Grant had been upset by his mentor’s increasingly long absences, but as the weeks ground past, Grant realized that Zeb trusted him to do the necessary work. I’m freeing him for the deep mission, Grant told himself. If I weren’t here to do this job, he wouldn’t be able to prepare for the mission.

Late one afternoon Muzorawa stepped into the lab and sagged tiredly into the empty chair next to Grant.

“How goes the struggle, my friend?”

“You’d think that someone would have solved the equations of motion for turbulent flow,” Grant complained, looking up from his work.

“Ah, yes, turbulent flow.” Muzorawa flashed a gleaming smile despite his evident weariness. “In all the centuries that physicists and mathematicians have studied turbulent flow, it still remains unresolvable.”

“It’s chaotic,” Grant grumbled. “You can’t predict its behavior from one blink of the eyes to the next.”

“Is that a new unit of measurement you’ve invented, the eyeblink?” Muzorawa chided gently.

Grant saw the weariness in Zeb’s red-rimmed eyes. “No,” he joked back, “I think Galileo invented it.”

“If you could solve the equations of turbulent flow you could predict the weather on Earth months in advance,” Muzorawa said, stroking his bearded chin. “That would win you a Nobel Prize, at least.”

“At least,” Grant agreed.

“Until then, you must do the best you can. We need to know as much as possible about the currents and how they change with depth.”

“I’m working on it,” Grant said, without feeling much confidence. “But the data points are few and far between, and the mathematics isn’t much help.”

“Situation normal,” said Muzorawa. “All fucked up.”

Grant flushed with shock. He’d never heard Muzorawa use indecent language before.

“I’ve got to get some sleep,” Zeb said. “Dr. Wo’s been driving us all very hard.” He struggled to his feet, then added, almost as an afterthought, “And the Old Man is pushing himself harder than any of us.”

Grant got out of his chair. “Wo’s driving himself? Why?”

With a weary smile, Muzorawa explained, “He intends to lead the mission. Didn’t you know?”

“You mean he’s going to go with you?”

“That is his intention.”

“But he can’t walk! He can’t even get out of his chair.”

“Yes, he can. The therapies are beginning to help him, at last. He can stand up by himself now—with braces on his legs.”

“He can’t lead a mission into the ocean in that condition.”

Muzorawa started for the lab door, and Grant saw that he himself was not walking very well. With a shake of his head, the Sudanese replied, “He claims it doesn’t matter. We really don’t need our legs inside the craft.”

“You don’t?”

“We’ll all be immersed in pressurized PFCL. It’s the only way to survive the gravity pull and the pressure of a deep dive.”

“What’s PFCL?” Grant asked.

“Perfluorocarbon liquid. It carries oxygen to the lungs and removes carbon dioxide. We’ll be breathing in a pressurized liquid.”

“You’ll be floating, then,” Grant said.

“Correct. It’s something like zero gee. That’s why we’re training for the mission in the dolphin tank.”

“I didn’t know.”

Muzorawa placed a finger over his Ups, the sign for silence. “Now you do, my friend.”