He beamed at his young companion. She smiled back, a quick flash of crooked white teeth, but she ducked her head when she saw Celine was watching.

“Would you like something?” Celine asked. What she had in mind was a low-level fizz, something to calm Astarte and make her feel more at ease. All the while that Wilmer had been speaking, the young visitor had fidgeted on the edge of her chair.

“Yes, mam.” Astarte gave another wriggle, but still she didn’t look at Celine. “Mam, I’d like ter go ter the bathroom. In fact, I have ter, right this minute, or I’ll pee on the chair.”

“Last person to do that was probably Calvin Coolidge,” Celine said. She wondered if Astarte heard her, because as soon as she added, “Private facility through that door, help yourself,” Star was off, vanishing into the bathroom.

“Ta, mam,” she said as the door closed.

“Nerves,” Wilmer said. “She’ll get over it. If it’s all right with you, we’ll wait ’til she comes back so she can hear everything and join in when she feels ready. Star’s not normally like this. You’ll see, she’ll perk up.”

“We’ll wait for her. I’ve got nothing to do.”

Wilmer nodded. Irony was wasted on him, or possibly he found it reasonable that the President of the United States had lots of free time. Celine looked for a tactful way to phrase her next remark — though tact, like irony, was alien to Wilmer.

“Astarte doesn’t seem like one of your usual colleagues.”

“She’s not. She’s a damn sight smarter. Smarter than them, smarter than me.”

At Celine’s skeptical glance, he added, “She is, you know. I’m sure of it, but most people can’t recognize that because the way she does things is so off the wall. You’ll see it when she’s at ease and can relax a bit. It’s her first time north of the line, too, so she’s nervous. When she feels at home she can get a bit crude. Some of the people at the New Sydney institute say she needs to be house-broken.”

“I can understand anyone’s feeling strange the first time they’re in this office. I know I was.” It seemed to Celine that Astarte Vjansander was already quite as crude as she needed to be. As for her talents, Celine would reserve judgment — although Wilmer was not one to underrate his abilities. “How did you find her?”

“I didn’t. She found me. Star thinks she’s twenty-four, but she’s not sure. She’s had a hell of a life. She was born in what used to be the Northern Territory, a few years after Alpha C, when the whole of Australia was still a wreck. She doesn’t know who her parents were, but she reckons they have to be dead. She was about seven years old, living in the middle of nowhere, when the Vjansander party found her during the first post-supernova survey. She ate bugs and little lizards and crocodile eggs and anything else she could find. She could speak some, which is pretty much a miracle, considering there was nobody else around. She didn’t know her name.”

“So where did she learn science?”

“Beats me. Breathed it in through her skin, I guess. Things in science that the average twelve-year-old would know, she’s never heard of. But she finds other ways. I don’t believe she works in words at all; it’s pictures and equations. After she arrived at the institute, at the first seminar that I took her to—”

“Later,” Celine said quietly. She hoped that the housebroken remark was not to be taken literally, because the bathroom door was opening. “Everything all right, Star?”

“Real good.” Astarte gave Celine her first full smile, and she seemed like a different person. “There’s nothing beats a pee, is there, when yer really have ter go? I feel loads better.”

“Like to take over, then?” Wilmer asked. “It’s your theory.”

“That’s all right.” Star went to her chair, staring at it before she sat down. “Did that Coolidge fella yer talked about really sit here and unload?”

“I doubt it.” Celine laughed. “But who knows? Silent Cal, they called him. He’d never have admitted it.” The meeting was taking a downward turn. “Wilmer? Where were we when you stopped?”

“I said I was churning out supernova theories by the cartload, and all of them crashed when I compared them with experiment. I showed ’em to Star in the first month after she came to New Sydney. She agreed they were all junk. Data rules. Theories have to fit observations, not the other way round. So I thought that was the end of it.”

Wilmer paused again, looking right past Celine and frowning at the wall of the office.

“But it wasn’t?” she prompted.

“For a long time I wasn’t sure. Star came to me with something new, but it made me real uncomfortable. Right, Star?”

She nodded. “He told me that I knew bugger-all about how to prove things, an’ all I was doing was making wild-arse guesses. And he told me if I kept dropping monkey-nut shells on the floor where he stepped on ’em in his bare feet, I’d get a boot up the wazoo and be out of there so quick I wouldn’t know where I was ’til I landed.”

Celine decided that she might as well relax. This meeting would go at its own pace, regardless of her preferences. “Still works barefoot, does he?” she said. “I used to tell him he only did it in case he ever needed to count to more than ten.”

Astarte hooted, and Wilmer said mildly, “Star still doesn’t know how to prove things, and she’s a bugger to have around the house because she never cleans up. But she’s infernal good at guessing. And there are great ideas that just can’t be proved until long after they’re discovered. Remember Max Planck.”

“The physicist?” Celine did remember Max Planck, but Wilmer had lost her. “Planck, like in Planck’s constant and the Planck length?”

“That’s him. A hundred and fifty years ago, there was a problem in physics that had everybody baffled. When you worked out the formula for how much energy should radiate from a closed box, you found that at short wavelengths the calculated value went to infinity. In the real world that obviously wasn’t the case. And data rules, theory only serves. But people who looked at the analysis all agreed with the results, and they were some of the best minds of the time — men like Rayleigh and Jeans and Boltzmann.

“So there was a big problem, and no solution. Then in 1900 Max Planck showed that if you used a trick, you could get a curve that fitted the experiments for all wavelengths. It was a really odd trick, because to get the right answer you had to use a formula that would apply only if the energy radiating out of the box came in little discrete packages. Planck gave the package a name, a quantum, and he could calculate how big each quantum had to be. He found that it involved a new constant. Planck’s constant.”

“Wilmer, I heard all this thirty-odd years ago, and then I forgot it. Do I really need to hear it again?”

His high forehead furrowed. “Yeah. Of course you do. Otherwise I wouldn’t be saying it, would I?”

“Go on, then.” Celine had forgotten how impervious Wilmer was to distractions. “Just keep in mind that we can go to dinner as soon as we feel ready to eat it.”

“I’m ready now. I’ll speed up a bit. Everybody thought that what Planck did in 1900 was a mathematical trick, that it didn’t mean squat in the real world. Energy couldn’t really come in little bundles. Even if the method worked for some reason when you were dealing with radiation from a closed box, that wasn’t the way the rest of the world operated.

“But then Einstein took what Max Planck had done at face value. He explained the photoelectric effect by saying that light, and all radiation, interacted with matter as though the light was made up of quanta. If a quantum had enough energy, it would jar an electron loose from a surface that the light hit. If it didn’t have enough energy — if the wavelength of the light was too long — then no matter how intense the beam of light, there would be no release of electrons.”