The temperature had originally been lowered to make the Ganymeans feel more at home, but by the time everybody had been crammed into the officers #146; mess for an hour or more and palls of tobacco smoke were hanging sullenly beneath the lights, it turned out to be just as well for all. Danchekker finished what he had been saying into the microphone of the headset that he was wearing over his sweater, then resumed his seat. Garuth replied from the far end of the room, where the Ganymean contingent was concentrated.
"I think I #146;d better let a scientist answer a scientist on that one, Professor." He looked down and behind him at one of the other Ganymeans. "Shilohin, will you respond?" All the Earthmen present who did not possess Ganymean kits had been equipped with headsets similar to Danchekker #146;s and could thus follow ZORAC #146;s translation of the proceedings. The machine #146;s ability in this respect was now quite passable although, mainly as a result of having conversed with many and varied individuals, it had not yet fully established a way to disentangle formal English constructions from American colloquialisms, a defect that sometimes yielded hilarious results.
Shilohin, the chief scientist of the Ganymean expedition, had already been introduced to the company. As Garuth sat down to make room, she rose to her feet and spoke. "First, I must congratulate the scientists of Earth for their superb piece of figuring out. Yes, as Professor Danchekker has just suggested, we Ganymeans do not enjoy a high tolerance to carbon dioxide. He and his colleagues were also absolutely correct in the picture that they had deduced of conditions on Minerva at the time of our departure #151;a planet that they had not even seen."
Shilohin paused a moment, waiting for that much to sink in. Then she continued. "The average concentration of radioactive, heat-producing substances in Minervan rocks was somewhat higher than is found on Earth. The interior of Minerva was thus hotter and molten to a greater degree, and the crust was thinner. The planet was therefore more active volcanically than Earth, a tendency that was further complicated by the strong tidal forces induced in the crust by Luna, which orbited closer to Minerva than it does to Earth today. This high level of volcanic activity released large quantities of carbon dioxide and water vapor into the atmosphere, resulting in a greenhouse effect that sustained a high enough surface temperature for the oceans to remain liquid and life to emerge. By terrestrial standards it was still sure-as-hell cold, but not nearly as cold as it would have been otherwise.
"This situation had always existed throughout the history of Minerva. By the time that our civilization was at its peak, however, a new epoch of tectonic activity was just beginning. The level of carbon dioxide in the atmosphere began showing a measurable increase. It soon became clear that it would only be a matter of time before the level grew beyond the point we could tolerate. After that our world would become, for us, uninhabitable. What could we do?" Shilohin let the question hang and cast her eyes around the room, apparently inviting the Earthmen to start a discussion.
After a few seconds a UNSA engineer at the back responded. "Well, we #146;ve seen some pretty remarkable examples of the kind of technology that you people had. I wouldn #146;t have thought you #146;d have found it much of a problem to figure out some way of simply winding the level back down again . . . some kinda planetwide climatic control, I guess. . . sump #146;n like that."
"Commendably on the ball," she said, with something that they took to be the equivalent of an approving nod. "We did in fact employ planetary climatic control to some degree, primarily to limit the extent of the Minervan ice caps. But when it came to tinkering with the chemical composition of the atmosphere, we were less certain of our ability to keep everything sufficiently under control; the balance was very delicate." She looked directly at the questioner. "A scheme along the lines you suggest was in fact proposed, but mathematical models indicated that there was too high a risk of destroying the greenhouse effect completely, and so of guaranteeing the end of life on Minerva even more quickly. We are a cautious people and do not take risks readily. Our government threw the idea out."
She remained silent and allowed them time to think of other possibilities. Danchekker didn #146;t bother to raise the notion that they might have tried importing terrestrial plant life as an attempt at introducing a compensatory mechanism. He already knew full well that the Ganymeans knew nothing of such a venture. Presumably that solution had been tried after Garuth #146;s expedition had departed. Further analyses by his scientists and discussions with ZORAC had indicated if that had been the objective of the exercise, it would not have succeeded anyway #151;a point that would surely not have escaped the Ganymean scientists at the time. For the moment this event was still as much a mystery as ever.
Eventually Shilohin spread her arm wide as if appealing to a class of children who were being a little slow that day. "Logically it #146;s very simple," she said. "If we left the carbon-dioxide level to rise, we would die. Therefore we could not allow it to rise. If we prevented the rise, as we could have done, there would have been too much of a risk of freezing the whole planet solid because the carbon dioxide kept Minerva warm through the greenhouse effect. We needed the results of the greenhouse effect to keep us warm because we were a long way from the Sun. Hence, we wouldn #146;t need it at all if we were nearer the Sun, or if the Sun were warmer."
Some of the faces in front of her remained blank; some suddenly looked incredulous. "It #146;s easy then," a voice called from near Hunt. "All you had to do was move Minerva in a bit or heat up the Sun." He meant that as a joke but the Ganymean began nodding her head in imitation of the human mannerism.
"Exactly," she said. "And those were the two conclusions we arrived at, too." A few gasps of amazement came from various parts of the room. "Both possibilities were studied extensively. Eventually a team of astrophysicists convinced the government that warming up the Sun was the more practicable. Nobody could find a flaw in the calculations, but, as always, our government was cautious and elected not to blow a wad on fooling around with the Sun. They wanted to see some proof first that the plan would work. . . Yes, Dr. Hunt?" She had noticed his hand hail raised to attract attention.
"Could you give us a few details on how they proposed to do such a thing?" he asked. "I think even the idea of contemplating something like that has astonished a few of us here." Mutters of agreement from all around echoed his sentiments.
"Certainly," she replied. "The Ganymeans, as most of you know by now, had developed a branch of technology that is not yet understood in your own world #151;a technology based on the principles of artificially generating and controlling the effect termed #145;gravity. #146; The proposal of the Ganymean astrophysicists involved placing three very large and very powerful projectors in orbit around the Sun, which would concentrate beams of space-time distortion #151; #145;gravity intensification #146; if you like, although that describes the effect of the process rather than its nature #151;at the Sun #146;s center. Theory predicted that this would induce an increase, effectively, in the Sun #146;s self-gravitation and produce a slight collapse of the star, which would cease when the radiation pressure again balanced the gravitational pressure. At the new equilibrium the Sun would radiate more strongly and, provided that all the right quantities were chosen, would just compensate for the loss of Minerva #146;s greenhouse effect. In other words we could now risk tampering with the carbon-dioxide level since, if we blew it and we started to freeze, we could put things right again by adjusting the solar constant. Does that answer the question sufficiently, Dr. Hunt?"
"Yes . . . very much so. Thank you." There were a thousand other questions that he could have asked at that moment, but he decided to leave them all for ZORAC later; for the time being he was having enough trouble even trying to visualize engineering on such a scale, yet Shilohin made the whole thing sound as routine as putting up an apartment block.
"As I said a moment ago," Shilohin resumed, "our government insisted on testing the theory first. Our expedition was formed for that purpose #151;to carry out a full-scale trial experiment on a Sun-like star elsewhere." She paused and made a gesture that was not familiar. "As it turned out, I guess they did the right thing. The star became unstable and went nova. We barely escaped with our lives. Garuth has just told you of the problem with the Shapieron #146;s propulsive system that resulted in the situation we have now #151;although we have aged less than twenty years since leaving Iscaris, on your time scale this all happened twenty-five million years ago. So here we are."
A chorus of mutterings broke out around the room. Shilohin waited for a few moments before continuing. "It #146;s a bit cramped in here and difficult to change places. Does anybody else have any questions for me before I sit down again and hand this back to Garuth?"
"Just one." The speaker was Lawrence Foster, commander of Main. "A few of us have been wondering. . . You developed a technology that was way ahead of ours #151;interstellar travel for instance. So you must have explored the Solar System pretty thoroughly in the course of all that. Somebody here #146;s taking bets that at least some Ganymeans got to Earth at some time. Care to comment on that?"
Shilohin seemed to flinch slightly for some reason. . . although it was difficult to be sure. She did not answer at once, but turned to exchange a few briefly muttered words with Garuth. Then she looked up again.
"Yes. . . you are correct. . ." The words coming through the headphones and earpieces of the listeners sounded hesitant, as if faithfully reproducing an uncertainty from the original utterances. "The Ganymeans came. . . to Earth."
A stir of excitement broke out across the room. This was something that nobody wanted to miss.
"Before your expedition went to Iscaris, I guess," Foster said.
"Yes, naturally . . . in the hundred Earth years or so before that time." She paused. "In fact a few of the crew of the Shapieron went to Earth before being recruited for the Iscaris expedition. None of them is here at the moment though."
The Earthmen were keen to hear more about their own world from beings who had actually been there long before they themselves had even existed. Questions began pouring spontaneously from all around the room.
"Hey, when can we talk to them?"
"Do you have any pictures stored away someplace?"
"How about maps or something?"
"I bet they built that city high up in that place in South America."
"You #146;re crazy. It #146;s not near old enough."
"Were these the expeditions to Earth to bring back the animals?"
The sudden increase in the enthusiasm of her audience seemed only to add to Shilohin #146;s confusion. She picked up the last question, the answer to which they already knew, as if hoping for some reason that it would divert attention from the rest.
"No, there were no shipments of animals to Minerva then, neither was there any talk of such a plan. That must have happened later on. Like you, we do not know why that was done."
"Okay, but about the #151;" Foster stopped speaking as ZORAC sounded in his ear.
"This is ZORAC speaking only to the Earthmen; I am not interpreting for Shilohin. I do not believe that the Ganymeans really wish to elaborate further for the time being. It might be a good idea to change the subject. Excuse me."
The puzzled frowns that immediately appeared all over the room confirmed that all the Earthmen had heard the same thing: apparently the message had not, however, been transmitted to the Ganymeans, who showed none of the reactions that it would, without a doubt, have elicited. An awkward silence reigned for just a second before Foster took firm control and steered them all into calmer waters.
"These things can wait until another time," he said. "Time #146;s getting on and we must be near dinner. Before we finish here, we ought to agree on our more immediate plans. The biggest problem seems to me to be the trouble you #146;ve got with your ship. How do you plan tackling that, and is there anything we can do to help?"
Shilohin conferred briefly with her companions and then sat down, giving a distinct impression of relief at getting out of the firing line. Her place was taken by Rogdar Jassilane, chief engineer of the Shapieron.
"We #146;ve had twenty years to figure out what the problem is, and we know how to fix it," he told them. "Garuth has described the effect of the trouble, which involved being unable to slow down the system of circulating black holes upon which the physics of the drive is based. All the time that drive was running, there was nothing we could do about it. We #146;re able to fix it now, but some key components were wrecked and to attempt replacing them from scratch would be difficult, if not impossible. What we really need to do is to have a look at the Ganymean ship that #146;s under the ice at Pithead. From the pictures you #146;ve shown us, it seems to be a somewhat more advanced design than the Shapieron. But I #146;m hopeful we will be able to find what we need there. The basic concepts of the drive appear to be the same. That #146;s the first thing we have to do #151;go to Pithead."
"No problem there," Foster said. "I #146;ll arrange . . . oh, excuse me a second . . ." He turned to throw an inquiring look at a steward, who had appeared in the doorway. "I see . . . thanks. We #146;ll be right along." He looked back toward Jassilane. "Sorry about that, but dinner #146;s ready now. Yes, in answer to your question, we can arrange that expedition for as early as you like tomorrow. We can talk about the details later tonight, but in the meantime, shall we all go through?"
"That will be fine," Jassilane said. "I will select some of our own engineers for the visit. In the meantime as you say, let #146;s all go through." He remained standing while the rest of the Ganymeans hoisted themselves to their feet behind him, forming a hopeless crush at the end of the room.
As the Earthmen also stood up and began moving back to make more space for the giants, Garuth made one final comment. "The other reason we wish to see the ship at Pithead is also very important to us. There is a chance that we might find some clues there which support your theory that the Ganymeans eventually migrated to another star system. If that is true, we might perhaps find something to identify which star it was."
"I think the stars can wait until tomorrow too," Jassilane said as he moved past. "Right now I #146;m more interested in that Earth food. Have you tried that stuff they call pineapple yet? It #146;s delicious #151;never anything like that on Minerva."
Hunt found himself standing beside Garuth in the crowd forming around the door. He looked up at the massive features. "Would you really do it, Garuth. . . go all the way to still another star, after all this time?"
The giant stared down and seemed to be weighing the question in his mind.
"Perhaps," he replied. "Who knows?" Hunt sensed from the tone of the voice in his ear that ZORAC had ceased operating in public-address mode and was now handling separately the different conversations taking place on either side. "For years now my people have lived on a dream. At this time more than any other, it would be wrong to destroy that dream. Today they are tired and think only of rest; tomorrow they will dream again."
"We #146;ll see what tomorrow brings at Pithead then," Hunt said. He caught the eye of Danchekker, who was standing immediately behind them. "Are you going to sit with us at dinner, Chris?"
"With pleasure, provided you are prepared to tolerate my being unsociable," the professor replied. "I absolutely refuse to eat with this contraption hanging round my head."
"Enjoy your meal, Professor," Garuth urged. "Let the socializing wait until afterward."
"I #146;m surprised you heard that," Hunt said. "How did ZORAC know we were talking in a group of three? I mean, it must have known that to put it through on your audio as well."
"Oh, ZORAC is very good at things like that. It learns fast. We #146;re quite proud of ZORAC."
"It #146;s an amazing machine."
"In more ways than you perhaps imagine," Garuth agreed. "It was ZORAC that saved us at Iscaris. Most of us were overcome by the heat when the ship was caught by the fringe of the nova; that was what caused many of the deaths among us. It was ZORAC that got the Shapieron clear."
"I really must stop calling its brethren contraptions," Danchekker murmured. "Wouldn #146;t want to upset it or anything if it #146;s sensitive about such matters."
"That #146;s okay by me." A different voice came through on the circuit. "As long as I can still call your brethren monkeys."
That was when Hunt learned to recognize when a Ganymean was laughing.
When they all sat down to dinner, Hunt was mildly surprised to note that the menu was completely vegetarian. Apparently the Ganymeans had insisted on this.