On the platform, Smeth was trying to stem further discussion and bring the proceedings to some kind of conclusion. The company had been at this for hours now, everything had been said at least twice, and people were getting cranky and tired.
“The time’s come for us to make a decision,” Smeth said harshly. “We have a problem that can’t be solved. But we’ve got to choose a course of action, nonetheless. Put quite simply, do we fight, run, or hide? Or pretend it isn’t so? I don’t believe I’ve heard any other suggestions tonight. So if anybody wants to start making motions, I’ll put them on the board and we can—”
The ushers were already starting to move down the aisles to get into position with their long-handled ballot boxes, when a burly figure dragging a bulky piece of electronic equipment shouldered his way past them.
“Hold it, Smeth!”
Smeth’s face showed annoyance. “The discussion just closed, Jao. There’s nothing more left to say. Take a seat with the others.”
Jun Davd leaned over to whisper something in Smeth’s ear. A slice of his face appeared in the holo projection, but the words weren’t audible.
“All right,” Smeth said. “Have your say. But try not to hold things up.”
Jao climbed to the stage with his gear and started plugging light fibers into the exposed holo panel while the projectionist hovered nearby. He said something to the projectionist, who nodded and took over the task while Jao strode to the lectern. A gigantic red-bearded face, disembodied, hovered over the auditorium; he hadn’t bothered with the niceties when he made his rough-and ready connections.
“When we dropped into the nucleus of the Milky Way from above the galactic plane about fifty of our years ago,” Jao began without preamble, “we saw a peculiar sight. It was a sort of arc of hot gas rising up out of the core at right angles to where you’d expect it to be for a galactic magnetic field.”
The audience stirred restively at what seemed to be an astronomy lecture coming when everybody was wound up with tension and ready to release it in the form of group action.
Jao appeared not to notice. The suspended face cocked a gigantic red eyebrow and went blithely on. “We postulated that something at the center of the galaxy was acting like a stupendous dynamo. The obvious candidate was a rotating black hole—the one we later used as a brake when we dived through the core.”
The blank part of the holo was suddenly filled with the Milky Way, making the disembodied head appear to be cloaked in the magnificence of stars. Jao had improved on the crude animated holo of finger-painted orange lines that he had first sketched so many years ago to illustrate his theory. Now a realistic image was there, drawn from the observatory’s photographic files and turned on its side to show an edge-on representation of the galaxy, with the central bulge glowing yellow.
The lines of force were still orange, though now they were an elegant computer sketch that made them flow in magnetic loops. The Milky Way tilted slightly, and now one could see the loops spinning faster around their common axis and flattening out to lie more within the galactic plane. Not all the lines of force were trapped, however. A small arclike spray still rose at the pole.
“The magnetic field was much more powerful than it ought to have been,” Jao said, “and it was growing. There was twice as much mass rotating around the galactic center as there should have been—the equivalent of two hundred million solar masses. It should have been gobbled up by the black hole, swept out by core explosions during the quasar epoch of the universe. But some process is replenishing it—maybe from a universe on the other side of the plenum.”
The Milky Way spun all the way up like a coin and presented its face. Now it could be seen as a great swirl of stars with an incandescent center. Jao’s holographic head presided over it like some raffish deity.
He had their attention now. The crowd had stopped fidgeting, and the background buzz of conversation had died down.
“We set up a long-term computer model at that time and started feeding data into it. The program was authorized to change its suppositions if data didn’t fit. We left the model running and plunged into the galactic core. All the senses of the tree were plugged into it. It saw, it listened, it sensed radiation and magnetism and gravitation, and it drew maps covering whole slices of the galaxy as we passed through.”
Shaded areas appeared briefly in the hologram to show the path swept by Yggdrasil’s spiraling orbit.
“Since our brush with the black hole, the computer has been processing sixty thousand years’ worth of real-time observational data. It’s a large enough sample of the history of the galaxy to show us how the charged arms grow. And to project into the past and future with the help of data from other sources. I’ve been awake for the last twenty hours polishing the results. And there’s no possible doubt…”
Now Jao’s theoretical plan of eight revolving spokes could be seen, superimposed in coruscating orange on a galaxy that was rotating at half their speed. They swept the spiral arms of stars like great flexible pinions, their ends trailing. They were growing outward all the time, becoming more vivid as they gained in power. It was very graphic.
The sun appeared as a yellow dot in the spiral arms of the galaxy, between spokes. And now one of the orange spokes brushed it.
“That happened three hundred million years ago,” Jao said. “Half of all animal families on earth were wiped out. In the oceans, ninety percent of species disappeared.”
Pictures floated in the holo, superimposed on the spinning wheel. They showed queer, scaly, flipper-limbed creatures with flat heads and big jaws, armored swimmers, many-legged bottom crawlers. They had come, Bram supposed, from Ame’s files.
Another orange pinion swept past Sol, then another, and another. Some of them were thick and bright, some were feeble. Some of them had not yet grown long enough to reach the yellow dot. Images of strange life forms flashed, disappeared.
“Those were the dinosaurs,” Jao went on. “They were big—bigger than our paleobiologists could believe at first, but we found bones in the diskworld museums. We’ll remake those animals some day for our game preserves.”
People gasped at the images: enormous armored quadrupeds with horned heads, finned backs, and spiked tails; great, plodding, thick-legged creatures with long necks, tiny heads, and massive tails; a fearsome monster with stalactite teeth and tiny front limbs rearing high and trying to smash through the eighty-foot steel fence that held it so as to get at a human zookeeper who was only as tall as its knee.
“Gone,” Jao said. “That was a major extinction. No land animal weighing more than twenty pounds survived. The little furry creatures who were humankind’s ancestors were among them.”
The great spoked mill continued to revolve. It had begun to subdivide again so that tenuous threads were trapped between some of the major arms, beginning their own growth.
“The extinctions come regularly now—about every twenty-six million years,” Jao’s floating head said somberly. “Some large, some small. And now we have some minor extinctions caused by these trailing arms, at intervals of from twelve to fifteen million years. The new arms haven’t quite settled into place yet.”
A thin orange wire passed across Sol like a wand.
“Twelve million years before the heyday of Original Man,” Jao said. “Followed by the return of that first, powerful arm that wiped out half of all animal families on earth. Only this time, Original Man was the dominant species.”
The audience sat stunned. In the silence, someone shouted, “I don’t believe it. A technical civilization could have found some way to protect itself!”