The Ganymeans had originated on Minerva, a planet that once occupied the position between Mars and Jupiter but which had since been destroyed. The bulk of Minerva’s mass had gone into a
violently eccentric orbit at the edge of the Solar System to become Pluto, while the remainder of the debris was dispersed by Jupiter’s tidal effects and formed the Asteroid Belt. Various scientific investigations, including cosmic-ray exposure-tests on material samples recovered from the Asteroid Belt, pinpointed the breakup of Minerva as having occurred some fifty thousand years in the past- long, long after the Ganymeans were known to have roamed the Solar System.
The discovery of a race of technically advanced beings from twenty-five million years back was exciting enough. Even more exciting, but not really surprising, was the revelation that the Ganymeans had visited Earth. The cargo of the spacecraft found on Ganymede included a collection of plant and animal specimens the likes of which no human eye had ever beheld-a representative cross section of terrestrial life during the late Oligocene and early Miocene periods. Some of the samples were well preserved in canisters while others had evidently been alive in pens and cages at the time of the ship’s mishap.
The seven ships that were to make up the Jupiter Five Mission were being constructed in Lunar orbit at the time these discoveries were made. When the mission departed, a team of scientists traveled with it, eager to delve more deeply into the irresistibly challenging story of the Ganymeans.
A data manipulation program running in the computer complex of the mile-and-a-quarter-long Jupiter Five Mission command ship, orbiting two thousand miles above Ganymede, routed its resuits to the message-scheduling processor. The information was beamed down by laser to a transceiver on the surface at Ganymede Main Base, and relayed northward via a chain of repeater stations. A few millionths of a second and seven hundred miles later, the computers at Pithead Base decoded the message destination and routed the signal to a display screen on the wall of a small conference room in the Biological Laboratories section. An elaborate pattern of the symbols used by geneticists to denote the internal structures of chromosomes appeared on the screen. The five people seated around the table in the narrow confines of the room studied the display intently.
“There. If you want to go right down to it in detail, that’s what it looks like.” The speaker was a tall, lean, balding man clad in a
white lab coat and wearing a pair of anachronistic gold-rimmed spectacles. He was standing in front and to one side of the screen, pointing toward it with one hand and clasping his lapel lightly with the other. Professor Christian Danchekker of the Westwood Biological Institute in Houston, part of the UN Space Arm’s Life Sciences Division, headed the team of biologists who had come to Ganymede aboard Jupiter Five to study the early terrestrial aninials discovered in the Ganymean spacecraft. The scientists sitting before him contemplated the image on the screen. After a while Danchekker summarized once more the problem they had been debating for the past hour.
“I hope it is obvious to most of you that the expression we are looking at represents a molecular arrangement characteristic of the structure of an enzyme. This same strain of enzyme has been identified in tissue samples taken from many of the species so far examined in the labs up in J4. I repeat-many of the species .
many different species . . .” Danchekker clasped both hands to his lapels and gazed at his miniaudience expectantly. His voice fell almost to a whisper. “And yet nothing resembling it or suggestive of being in any way related to it has ever been identified in any of today’s terrestrial animal species. The problem we are faced with, gentlemen, is simply to explain these curious facts.”
Paul Carpenter, fresh-faced, fair-haired and the youngest present, pushed himself back from the table and looked inquiringly from side to side, at the same time turning up his hands. “I guess I don’t really see the problem,” he confessed candidly. “This enzyme existed in animal species from twenty-five million years back
-right?”
“You’ve got it,” Sandy Holmes confirmed from across the table with a slight nod of her head.