“How the hell would I know? Why don’t you ask them?”
That time he just pointed, but it answered the question, sort of. Ron and Dad had made their decision. They were already stripped to their shorts, on the way down to the river.
Of course, Billy wouldn’t have asked them anything anyhow, since that would have meant actually speaking to my husband. But it made his point. “All right,” I said. “I’ll ask them when I get a chance. But next time you come to the door and knock. Okay? I’m tired of you sneaking around the house.” And then, as he started to turn away, still scowling—he scowled a lot, for a teenager—I had to add, “You sure they were actually talking about God?”
Rebecca had made one of Ron’s favorites for supper that night—hamburger Stroganoff, where it didn’t matter how tough that range-fed beef was because it had been ground to about the consistency of a Big Mac. I didn’t ask the question while we were eating. What we talked about was how muddy the river was getting, and whether our eel population was ever going to recover from the depredations we had waged on it in the bad times before rationing started, when you had to know somebody to get a pork chop at the Safeway. And then we talked about how I felt about starting another school year, and why Ron had to make a quick trip to some damn island in the Caribbean next week. He wouldn’t say the “why,” of course. He wouldn’t even say which island, but Rebecca had already been told to pack both his snorkel and his hill-climbing boots, so I was pretty sure it was Jamaica.
Then Rebecca cleared everything away and Ron tipped the last of the bottle of Peruvian merlot into our glasses. I thought that was a good time to ask them about what Billy had said.
They both looked puzzled. “He thought we were talking about God?” Ron said, and Dad said, “Let me see that paper.”
When he looked at it he began to laugh. He passed it to Ron, who laughed just about as much. Then Ron leaned over and gave me a kiss on the cheek. He turned to Dad. “You want to show her the book, Steve?”
Still grinning, my father reached over to where he had left his shoulder bag, and pulled out a book. What I mean to say here is a paper book. With the data printed on it in ink. The cover told me its title was The Universe Next Door, and it was written by someone named Marcus Chown. “I’ve had this for thirty years,” Dad informed me. “So when this story about the Moon came along I remembered it and pulled it down to show Ron.”
“What story about the Moon?” I asked, but Ron was already talking.
“A lot of it’s out of date, of course, but the guy had some interesting ideas,” he said.
“Always did,” Dad agreed. “Best science writer there was.”
I gave them both a look, about ten seconds apiece of my don’t-be-such-pains-in-the-ass,—will-you? look. “Ortho-positronium,” I reminded them.
“Oh, sorry,” Ron apologized. “It’s just that it takes a little explaining. Ortho-positronium is—I guess you could call it an element? Sort of, anyway?” He was looking at Dad, who shrugged. “All right,” Ron said, “let’s say it’s some kind of an element. A very simple one. Like hydrogen. Only instead of being made of an electron and a proton, the way hydrogen is, positronium is made of an electron and a positron. You know what a positron is?”
Dad gave him an indignant look. “Of course she knows what a positron is.”
I did, more or less—it was like an electron, only it had a positive charge, like a proton, instead of the electron’s negative one. I nodded because I was actually understanding what they were talking about. And then, all of a sudden, I wasn’t, because they began talking about mirror matter and it didn’t really sound as though they were talking to me. “Oh, hell,” I said, holding out my hand. “Why don’t you just give me the damn book?”
Having the actual book in my hands was better, but not a whole lot better. I was getting lost in stuff about time running backward and baby universes being born, and my father’s thirty-year-old scribblings in the margins of the pages didn’t help. Then it occurred to me to use the index. That was a lot like looking something up on my screen, though a lot slower, but then I did find out what they were talking about.
There turned out to be more than one kind of positronium, but the kind they were talking about was called ortho-positronium, never mind why. Ortho-positronium was something that got made in particle accelerators, and after it was made it didn’t stick around very long. It lived for.000000142 of a second, after which it blew up into three photons and was gone. Or, anyway, that’s when it was supposed to do it, but when they came down to measure the time exactly, the damn thing dissolved into photons one tenth of a percent faster than that.
Big deal, right? But they seemed to be sure about the numbers, God knows why, so I kept on reading and—after a lot of really weird stuff about mirror universes and such—I came to some talk about a man named Edward Harrison.
Harrison had an idea that might explain the discrepancy. Suppose, he said, that there’s a really advanced race of space aliens, off somewhere in infinite space and time. Suppose one of them wants to understand how the whole universe works. How would they go about it?
Well, if they were like human scientists, Harrison reasoned, they would make something like a computer model that they could study. Only, since they were really advanced superbeings, they would make a really good model. In fact it would be so good in all its details that it would contain every last aspect of the real universe.
Including, for example, us.
And the “us” in that model universe would have no idea they were nothing but computer simulations, as indeed we did not.
All right, I thought that was kind of interesting. Scary, even, although only in the way that ghosts and vampires were scary when you were eight years old and already pretty sure that such things didn’t really exist. What I didn’t see was what had made it interesting to Ron and Dad right now.
Then I took another look at Dad’s scribbles. One of them had a date next to it, and the date was a recent one: Woomara, 24 August 2022.
It only took a moment of searching on my omnibook to find what that meant. A couple of weeks earlier some radioastronomers at the old radio-telescope in Australia were doing some routine testing of their equipment. What that amounted to was just bouncing radar off the corner reflectors that early astronauts had left on the Moon a couple of generations before. And then they reported that, gosh, funny thing, the radar reported that the Moon now seemed to be about 350 meters closer to the Earth than it was supposed to be.
Well, that was peculiar, though what it meant I could not say.
So then I tried to track down every one of Dad’s scribbles in the margins of the Chown book. There were dozens of them. Most of them were only updating a lot of things Chown had got wrong, because he had written about them way back before the turn of the century and a lot had happened since. Some were just kind of puzzling, like a note about something called the heavy neutrino that was supposed to be like a hundred million billion times the mass of a proton—but when they finally caught one and measured it it was only about ten billion times heavier.
Then I hit a man’s name—John D. Barrow—and when my searcher finally located him it produced a paper he had written that answered all the questions.
If some superbeings did make that kind of a model and we were in it, Barrow said, they might not get everything straight on their first try. They would want to know if that was the case, of course, so they would be careful to build some kind of an error-checker into their model. Something that could detect mistakes ... and then correct them.