turned out, only the tiny glow of light around the obelisk remained to hold the night at bay.
They had honored the pledge that they had made and carried with them through all the years that had brought them here, from another place, from another time.
Beneath the ice field of Pluto lay the soil of Minerva.
The Giants had come home to lay their dead to rest.
chapter fifteen
The Shapieron reappeared out of space as suddenly as it had gone. The survefflance radars of Jupiter Five picked up an indistinct echo hurtling in from the void and rapidly consolidating itself as it shed speed at a phenomenal rate. By the time the optical scanners had been brought to bear, there it was, coasting into orbit over Ganymede just like the first time. This time, however, the emotions that greeted its arrival were very different.
The exchange of messages recorded in Jupiter Five’s Communications Center Day Log was enthusiastic and friendly.
Shapieron Good afternoon.
15 Hi. How was the trip?
Shap. Excellent. How has the weather been?
15 Pretty much the same as ever. How were the engines?
Shap. Never better. Did you save our rooms?
15 Same ones as before. You wanna go on down?
Shap. Thanks. We know the way.
Within five hours of the Shapieron touching down at Ganymede Main Base, familiar eight-foot-tall figures were clumping up and down the corridors at Pithead once again.
Hunt’s conversation with Danchekker had stimulated his curiosity about biological mechanisms for combating the effects of toxins and contaminants in the body, and he spent the next few days accessing the data banks of Jupiter Five to study up on the subject. Shilohin had mentioned that terrestrial life had evolved from early marine species that hadn’t developed a secondary circulation system because they hadn’t needed one; the warmer environment of Earth had imposed less strenuous demands for oxygen with the result that load-sharing had not been necessary. But it was this same mechanism that had later enabled the emerging Minervan land dwellers to adapt to a C02-rich atmosphere. The
terrestrial animals imported to Minerva had obviously possessed no similar mechanism, and yet they had adapted readily enough to their new home. Hunt was curious to find out how they did it.
His researches failed, however, to throw up anything startling. Each world had evolved its own family of life, and the two systems of fundamental chemistry on which the two families were based were not the same. Minervan chemistry was rather delicate, as Danchekker had deduced long ago from his study of the preserved Minervan fish discovered in the ruins of a wrecked Lunarian base; land animals inheriting such chemistry would be inherently sensitive to certain toxins, including carbon dioxide, and would require an extra line of defense to give them a reasonable tolerance if atmospheric conditions were extreme-hence the adaptation of the secondary system in the earliest land dwellers. Terrestrial chemistry was more rugged and flexible and could survive a far wider range of changes, even without any assistance. And that was really all there was to it.
One afternoon, Hunt found himself sitting in front of the view-screen in one of the computer console rooms at Pithead at the end of another unsuccessful attempt to uncover a new slant on the subject. Having nobody else to talk to, he activated his channel into the Ganymean computer network and discussed the problem with ZORAC. The machine listened solemnly without offering much in the way of comment while Hunt spoke. Afterward it had one comment. “I really don’t see much to add, Vic. You seem to have got it pretty wrapped up.”
“There’s nothing you can think of that I might have left out?” Hunt queried. It seemed a funny question for a scientist to put to a machine, but Hunt had come to know well ZORAC’s uncanny ability to spot a missing detail or a small flaw in what appeared to be a watertight line of reasoning.
“No. The evidence adds up to what you’ve already concluded:
Minervan life needed the help of a secondary system to adapt and terrestrial life didn’t. That is an observed fact, not a deduction. Therefore there’s not a lot I can say.”