Ta Shu tapped on the table screen and brought up a round map of the moon that he could scroll around on. “Here’s a feng shui problem for you. See how beat-up the south polar region is by meteor impacts? Including this really giant one, the South Pole–Aitken Basin. Biggest impact in solar system, except for Hellas on Mars. So, I couldn’t understand why so many impacts would come in from the southern sky, it being perpendicular to the solar plane. Where would all those big rocks come from, with only interstellar space above the south pole?”
“Hmm,” Fred said. “I never thought of that.”
“It’s a feng shui thought,” Ta Shu said. “But also, just astronomy. Clarification came to me from astronomer friends. Turns out the super-big impact that made South Pole–Aitken Basin probably happened when this region was nearer to the equator. Then the moon’s rotation over time naturally shifted a hole as big as that to one pole or other, just because of the way a lopsided sphere tends to spin. Like a top balancing itself.”
“Polhode precession!” Fred said. Matching spins was one attribute of entangled particles, so he had had occasion to think about spin, albeit at far smaller scales. He pondered the map as he ate. “So, these peaks of eternal light,” he said between bites. “They’re here because the moon’s polar axis is perpendicular to the solar plane. But I don’t understand why the moon’s axis isn’t parallel to the Earth’s axis, which is twenty-three degrees off the plane.”
“Me neither!” Ta Shu exclaimed, looking delighted that Fred had thought of this. “Seems like they should be the same, right? So I asked my astronomer friends about that too. They told me the moon and Earth formed in a big collision, which tilted Earth’s axis even more than it is now, like fifty or sixty degrees. Since then the two have been in a gravity dance with the sun, and the moon has moved out so far from the Earth that the sun has straightened it up. The sun has straightened the Earth too, but Earth had farther to go, so it’s only reached our twenty-three-degree angle, while the moon is almost vertical.”
“Does that difference mess up your feng shui work?”
“Yes, I think so.”
“So what will you do?”
“I’ll make adjustments. Work on local problems.”
“Such as?”
“I’ll visit the Chinese construction in the libration zone.”
“What’s that?”
“The two edges of the circle, you know—extending up from the south pole along longitudes ninety and one-eighty?”
“Zero longitude being the middle of the near side?”
“Yes, very good. So the same side of the moon is always looking at Earth, of course. Tidally locked. Another part of the gravity dance. Many moons in the solar system are like that.”
“So I’ve heard.”
“But all orbits in the solar system are elliptical. Kepler first understood this.”
“Kepler’s law,” Fred guessed.
“One of his laws. A feng shui genius. So, as one result of this law, when the moon is farther away from Earth in its orbital ellipse, it goes slower. When it’s closer it goes faster. Meanwhile it’s rotating on its axis at the same speed all the time.”
“Wait, I thought it was tidally locked?”
“Yes, but it still rotates—one day per month, you know.”
“Oh yeah.”
“So, but it doesn’t quite keep the same half facing Earth. Farther away it slows and we see more of the left side, then two weeks later it’s going faster, and shows us more of its right side.”
“Interesting!” Fred said.
“Yes. This waggling was first noted by Galileo, another very great feng shui master, when he was looking through his telescope. Like a man tilting his face while shaving, he said. He might have been the first ever to notice it. A telescope helps to see it. Libration, it’s called in English. Tianping dong.”
“And there’s new Chinese development running up this zone?”
“Yes.”
“Because?”
“Because feng shui experts suggested it!”
“But why?”
“Because in the libration zone, the view of Earth comes and goes. See what I mean? On the rest of the moon it isn’t like that. On the side of the moon facing Earth, Earth doesn’t move, it’s always in the same place overhead. Strange, don’t you think? It just hangs there in the sky! I want to experience this.”
“Interesting.”
“Yes. Then on the far side of moon, you never see Earth at all. Great for radio astronomy, I’m told. I want to see that too, see if it feels different.
“But in the libration zone, Earth rises into view, then sinks. That brings up all kinds of interesting questions. Should one build on the Earthmost side of the zone, and maximize the time Earth is visible, also the height it reaches over the horizon? Or is it best to build on far side of zone, where Earth might only poke a blue curve over the horizon for a short while? Any difference in feng shui terms?”
“Or practical terms?”
Ta Shu frowned. “Feng shui is practical.”
“Really? It’s not just aesthetics?”
“Just aesthetics? Aesthetics is very practical!”
Fred nodded dubiously. “You’ll have to teach me more about that.”
Ta Shu smiled. “I am a mere student myself. You work with computers, you must do mathematics, yes? Famous for its aesthetics, I’m told.”
“Well, but it has to work too. At least in my case. So, you’re going to visit the libration zones?”
“Yes. I have an old friend up there near the end of the line.”
Fred tapped on the map. “But Chinese stations never go into the northern hemisphere? Why is that? Is that feng shui too?”
“Yes, certainly. A matter of geographic propriety.”
“Propriety?”
“Not taking too much. The best places on the moon are the poles, precisely because of their water and the wind of solar particles, so again, very feng shui mix of aesthetic practicality. And in feng shui terms the two poles are about the same. China started building on the south pole first. Imagine if we had done the same in the north! Where would the other nations go? It might have been alarming for them. So this is propriety. Always polite to leave room for others. If this is the correct explanation, it’s very tactful.”
“Very,” Fred said. “Who decided?”
“The Party. But also, an ancient Chinese habit. China never did much in the way of territorial expansion, especially compared to some other countries. It looks bigger than it is because of coordinated effort.”
“Is this still feng shui?”
“Oh yes, of course. Balance the forces.”
“So feng shui is a kind of Daoist political geography?”
“Yes, very good!” Ta Shu laughed.
He was easy to please. Fred, who never really intended to make people laugh, was a little startled by this ease, but it was nice too. He nodded awkwardly, and said, “I want to learn more, but I have to get to my meeting with your local administrator.”
“Should be very interesting for you! Shall we meet and have a drink at the end of our day? I want to ask questions about quantum mysteries.”
“I would like that,” Fred said.
Fred was met by a pair of Chinese women in the lobby of the Hotel Star. They introduced themselves as Baozhai and Dai-tai, shook hands with him, then led him to the offices of the local official he was meeting, Chang Yazu.
Fred was still having to use the handrails to move around safely, and the two women glided beside him solicitously, waiting as he struggled to negotiate turns and the like. When they got to the administrative center, they took him to a room that was like a viewing bubble, poking above everything else in the settlement. The horizontal sunlight that was always obtained here threw their shadows all the way across the room. He said enthusiastic things about the view in as genuine a tone as he could muster, and almost met their curious gazes. Crater sublime; starscape amazing. Fred had never visited Earth’s southern hemisphere, and now he nodded politely as his hosts pointed out the Southern Cross overhead, and a blob with a texture like the Milky Way’s, which they said was a Magellanic Cloud. A couple of points of light moving through the stars were apparently satellites in lunar polar orbits. A larger satellite, like a little oblong moon, brilliant on its sunward side and a velvet gray on its dark side, was an asteroid, his hosts told him, brought into lunar orbit for its carbonaceous chondrite. The moon lacked carbon, so chunks of this asteroid were being cut off and dropped to the surface in collisions as slow as could be arranged. This kept the resulting meteorites mostly unvaporized and available for use.