Donald Moffitt - Genesis 02

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 realtime 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