Second Genesis gq-2

by Donald Moffitt

  “Yes, I’ve played back the sequence many times,” Ame said offhandedly. “Jun Davd, is there any danger of the next core explosion wiping out life in this galaxy, as it did in the old one?”

  Bram watched Ame with a pride of authorship he felt for all his descendants—though in Ame’s case he could claim only one thirty-second of the credit. His great-great-great-granddaughter had turned out well, he thought. She was a pert, direct, lively girl with wide green eyes and corn-colored hair. Though she was scarcely forty years old, she was a complete person with good sense and integrated views.

  Her interest was in something she called reconstructive paleontology, and with a small group of similar-minded young people who styled themselves such things as comparative geologists and theoretical terralogists, she was attempting to come up with a self-consistent picture of the bygone planet, Earth, that had spawned Original Man. The store of data they had to go on was skimpy—the highly condensed primers of various descriptive sciences that had been included in the Message plus whatever clues they could gather from literary works, dictionary line drawings, parallel processes on the Father World, and similar sources. But she and her friends had been ingenious and had gone surprisingly far with their small database.

  To Smeth’s chagrin, Ame had brought along two colleagues from the paleoearth department: a woman named Abiga, whose specialty was comparative geology, and a young man named Jorv, who was only in his twenties and who bubbled over with enthusiasm for something he called “deductive zoology.”

  Bram felt sorry for Smeth, watching him hover and fuss around Ame. Youth had not been kind to the gawky physicist; it had robbed him of a certain acquired gravity and left him awkward and abrasive again. When Smeth had invited Ame to watch the hole approach with the astronomy and physics group, he had expected to monopolize her—and now she could not be pried loose from her chums. Smeth still was trying to figure out if Jorv was attached somehow to Abriga or whether he represented sexual competition.

  As if that weren’t bad enough, Jun Davd was being courtly.

  “No, we believe the Milky Way is reasonably tame now,” Jun Davd said in answer to Ame’s question. “The quasar epoch used up the tremendous quantity of material within the core that might fuel an event on that titanic a scale and stored it conveniently in the form of the black hole we’re orbiting now. The subsequent explosions—like the one that caused the ‘smoke ring’ Smeth mentioned—obviously could not have been violent enough to wipe out life in the Milky Way … though they might have had some minor effect on species.”

  Ame and Jorv exchanged a peculiar glance.

  “When did the last core explosion take place?” Ame asked. “Or is there any way of estimating it?”

  “Yes, indeed, there is,” Jun Davd said. “We’ve been observing the so-called smoke ring over a period of more than fifteen thousand objective years during our dive into the galactic bulge. It keeps expanding and contracting to strike a balance between its rotantional velocity and the gravitational attraction of the center. From the rate of oscillation, we calculate that the last core explosion took place approximately one hundred and forty-one million years ago.” He smiled. “And I gather that Original Man evolved after that event, since he broadcast his Message only seventy-four million years ago.”

  “Jun Davd,” Ame said, hesitating, “when is the next core explosion due?”

  Smeth opened his mouth, but Jun Davd beat him to it.

  “Theoretically, there shouldn’t be one. The last explosion should have depleted the galactic center of the necessary mass. The smoke ring’s velocity and distance suggest an ejected mass of one hundred million solar masses—and an explosion powered by converting the equivalent of ten thousand suns completely into energy. Now a black hole of one hundred million solar masses sits in the center, and except for the observed stars around it, the center should pretty well have been swept clean.” He frowned.

  “But?”

  “By generating artificial profiles of the twenty-one centimeter line, we’ve determined the amount of invisible matter that must be rotating around the galactic center.” He paused, decided to add to his explanation. “You see, that gave us the Doppler shift of the neutral hydrogen present.”

  She seemed to know what he was talking about. “The faster the rotation, the greater the mass?”

  He brightened. “Precisely. And the figure we get is two hundred million solar masses.”

  “Twice what ought to be there?”

  He nodded. “And we don’t know where it came from.”

  “Jao has a theory about that, though,” Bram put in.

  “I’ve heard about Jao’s theories, Bram-tsu.” Ame laughed. She was a dutiful descendant, always giving him an ancestral honorific in the abbreviated Chin-pin-yin form. He had told her over and over again to simply call him Bram, but like so many of the young people, she was a stickler for convention; it was as if the newest generation were trying to revive a structure of human tradition all by themselves.

  Jao, hearing his name, twisted his shaggy red head around from the console he had been working. “Yah,” he said, “there has to be some kind of mechanism for renewing matter in the core of the galaxy. It doesn’t have to amount to much—about seven-tenths of a solar mass per year.”

  “The problem is,” Jun Davd said indulgently, “that this hypothetical flow of matter isn’t coming from the galactic plane, and it isn’t coming from outside the galaxy, as when the Whirlpool cannibalized the Bonfire.”

  “So that leaves one place, right?” Jao continued. “The nucleus of the galaxy itself. Matter just appears there.”

  Smeth found his voice. “That’s preposterous!” he said. “It’s nothing more than a rehash of the old discredited theory of the continuous origin of matter!”

  “No, listen, this is a new idea based on the heavy-neutrino model of the universe,” Jao insisted. “If neutrinos have mass, then they could account for ninety percent of the mass of the universe, and ordinary matter is a film wrapped around great clumps of neutrinos. And where do the clumps come from? I’m glad you asked that. They’re simply the walls of a great spongy cellular structure, one of whose bubbles is our own dear old universe. This all takes place in eleven-dimensional space-time, needless to say. The different domains are a necessary consequence of the first moments of creation—and you’ll notice that the domains would be nonregular in shape, and that fits in well with the observed fibrous structure of the universe. So how do we create matter in the nuclei of galaxies without violating baryon conservation?”

  He glared around at everybody.

  “I have a feeling he’s going to tell us,” Bram said.

  “We don’t!” Jao proclaimed triumphantly. “We have an exchange of neutrinos and un-neutrinos through the walls of the domains. The walls leak. Why are the leaks located in the centers of galaxies? Easy. Because of the hypermasses there—the super black holes sinking deep into the plenum and stretching the warp and woof of space-time to its limits. You may well ask why no right-handed neutrinos have ever been observed, despite the predictions of theory! Because the scales are balanced in other domains, that’s why! So symmetry is preserved in the larger sense. Baryons—like protons and neutrons—can’t cross the domain walls without instantly decaying. But un-neutrinos exhibit antidecay and assemble themselves into elementary particles, in the reverse of beta decay.”

  Smeth was beside himself. His face was red as a tomato, and he seemed in danger of bursting.

  “You can’t do that!” he said, his voice cracking. “How can you change leptons into baryons?”

  “With mesons as the mediators, naturally,” Jao said. “And while we’re at it, what do you think happened to those missing solar neutrinos you tried to detect in that chlorine tank experiment of yours back on the Father World? I’ll tell you. They were falling in, not out. They were being funneled through the domain wall to another domain. There must have been a black hole on the other side.”

  Smeth open
ed his mouth indignantly to reply, but Ame cut in to get the subject back on track.

  “So what it boils down to is that, by whatever mysterious process, there’s enough material in the center of the galaxy for another explosion, even though it shouldn’t be there?” she asked.

  “Admirably put,” Jun Davd said.

  “And that presumably this process acted in the past to cause periodic explosions?”

  “Yes.”

  Ame mulled it over. “Could core explosions be a byproduct of some other process? Or vice versa?”

  Jun Davd pursed his lips. “That’s an interesting question. More interesting than you know. Why do you ask?”

  “I’m trying to pin down periodicity. You said that the last core explosion in the Milky Way must have taken place one hundred and forty-one million years ago?”

  “Thereabouts.”

  “It’s a very interesting coincidence.”

  Her zoologist friend, Jorv, nodded energetically.

  “Coincidence? How?” Jun Davd asked.

  “Because one hundred and thirty-nine million years ago was when the dinosaurs became extinct.”

  Jorv burst out, “Practically on the heels of the explosion!”

  “What is a dinosaur?” Jun Davd inquired.

  “It was a very large animal that predated humans on Earth. Though they couldn’t have been as large as the Message described them—there must be some error or misinterpretation of scale. We have line sketches of several of the main types. They were the dominant form of life on Earth for about one hundred and thirty million years, then they abruptly vanished.”

  “Like Original Man,” Jun Davd murmured. “I take your point.’

  “How big were they?” Jao asked.

  “They were built on the same general plan as human beings,” Ame said. “Four limbs, bilateral symmetry, bony skeleton—so I suppose it’s possible that they could have been as much as three or four times human size. We’ve done computer simulations of them, and with a thicker bone cross section as compared to a human, certain efficiencies in oxygenating tissues, a slower metabolism, and so forth, we think it’s possible for them to have weighed as much as a ton.”

  Jao whistled. “That big?”

  “The Message data has some of them attaining a length of ninety feet and weighing as much as fifty tons.” She smiled. “But of course that’s nonsense. No creature with an internal skeleton could attain that size. It would have to have some sort of exoskeleton supporting its weight like a scaffolding, or an external shell, like the orthocone creatures on the Father World—and of course, then they couldn’t be very active.”

  Jorv’s boyish face had been working, and now he said, “Don’t take away my big dinosaurs, Ame! I’ve been running a different set of assumptions through the computer, and I can get bipeds up to twenty feet tall and quadrupeds twice that scale.”

  “Bone is bone, and histology is histology,” Ame said tolerantly, “but if you want to postulate more efficient absorptive surfaces than human beings have, and a food intake of a quarter ton a day, and radiators to get rid of body heat, you’re welcome to your big dinosaurs.”

  It was the usual sort of professional banter, but Bram could all but see Smeth’s suspicious mind working to make something more of it. Poor Smeth, he thought. The case was hopeless, but it wasn’t up to him to tell Smeth that!

  “So these … dinosaurs disappeared at the approximate time of the core explosion?” Jun Davd mused. “Hmmm … allowing time for some undefined process to spread to Earth’s latitude in the galaxy at the quite reasonable rate of about one and one-half percent of the speed of light?”

  “Not just the dinosaurs, Jun Davd,” Jorv said. “They disappeared completely—every last one of them—but many other land animals and most marine species disappeared at the same time. If the record that we’ve been given is correct.”

  “And about one hundred fifty-five million years before that mass extinction,” Ame put in, “there was another major extinction in which half of all animal families were wiped out. And one hundred and fifty-five million is almost an exact multiple of twenty-six million.”

  “What’s the significance of twenty-six million?” Jun Davd asked.

  Ame and Jorv fell over themselves to be the one to tell him. Ame won out. “The geological record we got from Original Man—and you must realize it’s only a summary, without the detail we’d like—shows that there seem to be major species die-offs at intervals that work out to an average of about twenty-six million years.”

  Jorv amended: “In two cases, there seems to have been a follow-up extinction of species at an interval somewhere between thirteen and fifteen million years.”

  “That’s what worries me,” Ame said. “There were two cycles of extinction that followed the dinosaur disappearances that don’t appear to have affected the precursors of Homo sapiens, but add another thirteen million years to that and you get a value pretty close to the time when Original Man’s Message was cut off.”

  “Jao,” Jun Davd said, turning around. “What sort of correlation can we get on that major date of one hundred and fifty-five million years prior to the last core explosion?”

  Jao’s fingers flew over his board. “It’s hard to say, Jun Davd. We got one scenario that could have put another core explosion about there. You know, the one where we factored in the expanding molecular ring at the center. But we don’t know enough yet.”

  Jun Davd turned back to Ame. “There’s not enough to go on,” he said. “We have one striking correlation of a core explosion with one of your two major extinctions and one more possible correspondence. But there’s been no more explosion since the dinosaurs disappeared and no periodic phenomenon that subdivides the major events into twenty-six-million-year cycles.”

  “How about this?” Jao said. “Imagine something that sweeps the galaxy like the spokes of a wheel. Imagine eight spokes. Four major spokes, like the arms of a cross. And in between, four minor spokes, also arranged roughly as a cross. As Man’s sun orbits the galactic center, it encounters a spoke approximately every twenty-six million years.”

  “Why eight spokes?” Jun Davd inquired.

  “You have to start somewhere. Eight has a nice symmetry. Besides, it works out in lots of ways. You’ll see in a minute.”

  “What do you mean?” Ame asked, leaning forward.

  “Look,” Jao said. He did something to his console, and the tremendous scene behind the holo wall vanished, to be replaced by the rough scrawls Jao was tracing on his touch pad with one meaty forefinger.

  “Hey, wait a minute!” Smeth protested.

  “The universe won’t go away,” Jao said. “I’ll bring it back in a minute. I want everyone to see this.”

  A bold vertical line in screaming orange grew in the illusory void behind the wall. “We start with a two-spoke model,” Jao said. “Two opposing arms, like a lot of cosmic phenomena. Like galactic gas jets, for example. Now we add another pair of arms at right angles.”

  He slashed another orange line across the first. It wasn’t quite horizontal—apparently by design, because as everyone watched, the second pair of arms, responding to whatever crude instructions he had punched into his board, slowly turned until the adjustment was made.

  “You see, there’s some repulsive force holding them equidistant from the two previous arms,” Jao said. “Like magnetism. Now we subdivide one more time.”

  Two more crude slashes turned the cross into an asterisk. This time the finger-painted lines weren’t as thick, and they were a paler orange. They were also slightly out of position, but after a moment the second cross rotated with respect to the first until all the angles were equal.

  “These are the baby arms,” Jao said. “They’re not full-grown yet. They’re weaker. That’s why I drew them skinny.”

  Jorv, with growing excitement, said, “What did you mean when you said it works out?”

  “For starts, when you multiply these twenty-six-million-year events of
yours by eight, you get a figure of two hundred and eight million years. Which is a pretty good match for the length of time it takes Man’s sun to make one complete orbit around the galactic center.”

  “Very suggestive,” Jun Davd said. “Eight events per solar orbit. Of course, you’re assuming either that the spokes are stationary, or the sun is stationary, or the spokes are rotating at twice the sun’s speed at the radius of the sun’s orbit.”

  “Like I said, you have to start somewhere,” Jao said. “I like figures that come out even. So you begin with a nice regular series—two, four, eight. And multiples of orbital speed—which incidentally would put the end of a full-grown spoke somewhere at the rim of the galaxy.”

  “Why not a ten-spoke model?” Smeth interrupted, with a sidelong glance at Ame. “You’d get a multiple of two hundred and sixty million years, which is closer to the two-hundred-and-fifty-million-year galactic year that some of us prefer!”

  Jao shrugged. “Suit yourself. You could make that work, too, with a little fiddling with the relative velocities. You can work out the figures if you like. But an eight-spoke model’s more elegant.”

  “I take it there’s more,” Jun Davd prompted.

  Jao brightened. “Yah. Watch this.”

  His thick fingers busied themselves on the board, and a bright yellow dot appeared about halfway out on one of the orange spokes. It began tracing a slow circle around the center of the geometric figure. A moment later the eight-armed figure began to revolve, too, at a somewhat faster rate, with the arms continually overtaking the dot.

  “Now, let’s label the arms so we can keep track of them,” Jao said.

  Letters popped up, alphabetizing the arms. Jao did not stop the process quickly enough, and a second round of letters began to subtend the first.

  “That’s okay, leave it,” Jao said. “If I were laying this out flat, I’d be going past eight into the next cycle, anyway.”

  Ame and Jorv were intent on the garish sketch hanging in the space before them. Bram could see Ame’s lips moving as she counted to herself.