Inherit the Stars

by James P. Hogan

  "So, Minerva cooled to a mean surface temperature somewhat colder than Earth's but not as cold as you might think. With cooling came the formation of increasingly more complex molecules, and eventually life emerged. With life came diversification, followed by competition, followed by selection—in other words, evolution. After many millions of years, evolution culminated in a race of intelligent beings who became dominant on the planet. These were the beings we have christened the Ganymeans.

  "The Ganymeans developed an advanced technological civilization. Then, approximately twenty-five million years ago, they had reached a stage which we estimate to be about a hundred years ahead of our own. This estimate is based on the design of the Ganymean ship we've been looking at here, and the equipment found inside it.

  "Some time around this period, a major crisis developed on Minerva. Something upset the delicate mechanism controlling the balance between the amount of carbon dioxide locked up in the rocks and that in the free state; the amount in the atmosphere began to rise. The reasons for this are speculative. One possibility is that something triggered the tendency toward high volcanic activity inherent in Minerva's structure—maybe natural causes, maybe something the Ganymeans did. Another possibility is that the Ganymeans were attempting an ambitious program of climate control and the whole thing went wrong in a big way. At present we really don't have a good answer to this part. However, our investigations of the Ganymeans have hardly begun yet. There are still years of work to be done on the contents of the ship alone, and I'm pretty certain that there's a lot more waiting to be discovered down under the ice here.

  "Anyhow, the main point for the present is that something happened. Chris Danchekker has shown . . ." Another file reference appeared on the bottom of the screen. ". . . that all the higher, air-breathing Minervan life forms would almost certainly have possessed a very low tolerance to increases in carbon-dioxide concentration. This derives from the fundamental system of microchemistry inherited from the earliest ancestors of the line. This implies, of course, that the changing surface conditions on Minerva posed a threat to the very existence of most forms of land life, including the Ganymeans. If we accept this situation, we also have a plausible reason for supposing that the Ganymeans went through a phase of importing on a vast scale a mixed balance of plant and animal life from Earth. Perhaps, stuck out where it was, Minerva had nothing to compare with the quantity and variety of life teeming on the much warmer planet Earth.

  "Evidently, the experiment didn't work. Although the imported stock found conditions favorable enough to flourish in, they failed to produce the desired result. From various bits of information, we believe the Ganymeans gave the whole thing up as a bad job and moved out to find a new home somewhere outside the Solar System. Whether or not they succeeded we don't know; maybe further study of what's in the ship will throw more light on that question."

  Hunt stopped to pick up a case from the desk and went through the motions of lighting a cigarette. The break seemed to be timed to give the viewers a chance to digest this part of his narrative. A subdued chorus of mutterings broke out around the room. Here and there a light flared as individuals succumbed to the suggestion from the screen. Hunt continued:

  "The native Minervan land species left on the planet soon died out. But the immigrant types from Earth enjoyed a better adaptability and survived. Not only that, they were free to roam unchecked and unhindered across the length and breadth of Minerva, where any native competition rapidly ceased to exist. The new arrivals were thus free to continue the process of evolutionary development that had begun millions of years before in the oceans of Earth. But at the same time, of course, the same process was also continuing on Earth itself. Two groups of animal species, possessing the same genetic inheritance from common ancestors and equipped with the same evolutionary potential, were developing in isolation on two different worlds.

  "Now, for those of you who have not yet had the pleasure, allow me to introduce Cyril." The picture of Hunt vanished and a view of the man-ape retrieved from the Ganymean ship appeared.

  Hunt's voice carried on with the commentary: "Chris's team has made a thorough examination of this character in the Jupiter Four laboratories. Chris's own summary of their results was, quote: 'We consider this to be something nearer the direct line of descent toward modern man than anything previously studied. Many fossil finds have been made on Earth of creatures that represented various branches of development from the early progressive apes in the general direction of man. All finds to date, however, have been classed as belonging to offshoots from the mainstream; a specimen of a direct link in the chain leading to Homo sapiens has always persistently eluded us. Here, we have such a link.' Unquote." The image of Hunt reappeared "We can be fairly sure, therefore, that among the terrestrial life forms left to develop on Minerva were numbers of primates as far advanced in their evolution as anything back on Earth.

  "The faster evolution characteristic of Minerva thus far was repeated, possibly as a result of the harsher environment and climate. Millions of years passed. On Earth a succession of manlike beings came and went, some progressive, some degenerate. The Ice Age came and moved through into its final, glacial phase some fifty thousand years ago. By this time on Earth, primitive humanoids represented the apex of progress—crude cave dwellers, hunters, makers of simple weapons and tools chipped out of stone. But on Minerva, a new technological civilization already existed: the Lunarians—descended from the imported stock and from the same early ancestors as ourselves, human in every detail of anatomy.

  "I won't dwell on the problems that confronted the developing Lunarian civilization—they're well-known by now. Their history was one long story of war and hardship enacted around a racial quest to escape from their dying world. Their difficulties were compounded by a chronic shortage of minerals, possibly because the planet was naturally deficient, or possibly because it had been thoroughly exploited by the Ganymeans. At any rate, the warring factions polarized into two superpowers, and in the showdown that followed they destroyed themselves and the planet."

  Hunt paused again at this point to allow another period of consolidation for the audience. This time, however, there was complete silence. Nothing he had said so far was new, but he had formed a set selected from the thousand and one theories and speculations that had raged around Navcomms for as long as many could remember. The silent watchers in the theater sensed that the real news was still to come.

  "Let's stop for a moment and examine how well this account fits in with the evidence we have. First, the original problem of Charlie's human form. Well, that's answered: He was human—descended from the same ancestors as the rest of us and requiring nothing as unlikely as a parallel line to explain him. Second, the absence of any signs of the Lunarians on Earth. Well, the reason is quite obvious: They never were on Earth. Third, all the attempts to reconcile the surface geography of Charlie's world with Earth become unnecessary, since by this account they were indeed two different planets.

  "So far so good, then. This by itself, however, does not explain all the facts. There are some additional pieces of evidence which must be taken into account by any theory that claims to be comprehensive. They can be summarized in the following questions:

  "One: How could Charlie's voyage from Minerva to our Moon have taken only two days?"

  "Two: How do we explain a weapons system, consistent with the Lunarian level of technology, that was capable of accurate registration over a range extending from our Moon to Minerva?

  "Three: How could the loop feedback delay in the fire-control system have been substantially less than the minimum of twenty-six minutes that could have applied over that distance?

  "Four: How could Charlie distinguish surface features of Minerva when he was standing on our Moon?"

  Hunt looked out from the screen and allowed plenty of time for the audience to reflect on these questions. He stubbed out his cigarette and leaned forward toward the camera, his elbows coming to rest
on the desk.

  "There is, in my submission, only one explanation which is capable of satisfying these apparently nonsensical requirements. And I put it to you now. The moon that orbited Minerva from time immemorial up until the time of these events fifty thousand years ago—and the Moon that shines in the sky above Earth today—are one and the same!"

  Nothing happened for about three seconds.

  Then gasps of incredulity erupted from around the darkened room. People gesticulated at their neighbors while some turned imploringly for comment from the row behind. Suddenly the whole theater was a turmoil of muttered exchanges.

  "Can't be!"

  "By God—he's right!"

  "Of course . . . of course . . . !"

  "Has to be . . ."

  "Garbage!"

  On the screen Hunt stared out impassively, as if he were watching the scene. His allowance for the probable reaction was well timed. He resumed speaking just as the confusion of voices was dying away.

  "We know that the moon Charlie was on was our Moon—because we found him there, because we can identify the areas of terrain he described, because we have ample evidence of a large-scale Lunarian presence there, and because we have proved that it was the scene of a violent exchange of nucleonic and nuclear weapons. But that same place must also have been the satellite of Minerva. It was only a two-day flight from the planet—Charlie says so and we're confident we can interpret his time scale. Weapons were sited there which could pick off targets on Minerva, and observations of hits were almost instantaneous; and if all that is not enough, Charlie could stand not ten yards from where we found him and distinguish details of Minerva's surface. These things could only be true if the place in question was within, say, half a million miles of Minerva.

  "Logically, the only explanation is that both moons were one and the same. We've been asking for a long time whether the Lunarian civilization developed on Earth or whether it developed on Minerva. Well, from the account I've given, it's obvious it was Minerva. We thought we had two contradictory sets of information, one telling us it was Earth and the other telling us it wasn't. But we had misinterpreted the data. It wasn't telling us anything to do with Earth or Minerva at all—it was telling us about Earth's or Minerva's moon! Some facts told us we were dealing with Earth's moon while others told us we were dealing with Minerva's moon. As long as we insisted on introducing, quite unconsciously, the notion that the two moons were different, the conflict between these sets of facts couldn't be resolved. But if, purely within the logical constraints of the situation, we introduce the postulate that both moons were the same, that conflict disappears before our eyes."

  Shock seemed to have overtaken the audience. At the front somebody was muttering, "Of course . . . of course . . ." half to himself and half aloud.

  "All that remains is to reconcile these propositions with the situation we observe around us today. Again, only one explanation is possible. Minerva exploded and dispersed to become the Asteroid Belt. The greater part of its mass, we're fairly sure, was thrown into the outer regions of the Solar System and became Pluto. Its moon, although somewhat shaken, was left intact. During the gravitational upheaval that occurred when its parent planet broke up, the satellite's orbital momentum around the Sun was reduced and it began to fall inward.

  "We can't tell how long the orphaned moon plunged steadily nearer the Sun. Maybe the trip lasted months, maybe years. Next comes one of those million-to-one chances that sometimes happen in nature. The trajectory followed by the moon brought it close to Earth, which had been pursuing its own solitary path around the Sun ever since the beginning of time!" Hunt paused for a few seconds. "Yes, I repeat, solitary path! You see, if we are to accept what I believe to be the only satisfactory explanation open to us, we must accept also its consequence: that until this point in time, some fifty thousand years ago, planet Earth had no moon! The two bodies drew close enough for their gravitational fields to interact to the point of mutual capture; the new, common orbit turned out to be stable, and Earth adopted a foundling it has kept right up to this day.

  "If we accept this account, many of the other things that have been causing problems suddenly make sense. Take, for example, the excess material that covers most of Lunar Farside and has been shown to be of recent origin, and coupled with that, the dating of all Farside craters and some Nearside ones to around the time we're talking about. Now we have a ready explanation. When Minerva blew up, what is now Luna was sitting there right in the way of all the debris. That's where the meteorite storm came from. That's how practically all evidence of the Lunarian presence on Luna was wiped out. There's probably no end to remains of their bases, installations, and vehicles still there waiting to be uncovered—a thousand feet below the Farside surface. We think that the Annihilator emplacement at Seltar was on Farside. That suggests that what is Farside to Earth today was Nearside to Minerva; hence it makes sense that most of the meteorite storm landed where it did.

  "Charlie appears to have referred to compass directions different from ours on the Lunar surface, implying a different north-south axis. Now we see why. Some people have asked why, if Luna suffered such an intense bombardment, there should be no signs of any comparable increase in meteorite activity on Earth at the time. This too now makes sense: When Minerva blew up, Luna was in its immediate vicinity but Earth wasn't. And a last point on Lunar physics—We've known for half a century that Luna is formed from a mix of rocky compounds different from those found on Earth, being low in Volatiles and rich in refractories. Scientists have speculated for a long time that possibly the Moon was formed in another part of the Solar System. This indeed turns out to be true if what I've said is correct.

  "Some explanations have suggested that the Lunarians set up advanced bridgeheads on Luna. This enabled their evident presence there to be reconciled with evolutionary origins on Minerva, but raised an equally problematical question: Why were they struggling to master interplanetary space-flight technology when they must have had it already? In the account I have described, this problem disappears. They had reached their own moon, but were still some ways from being able to move large populations to anyplace as remote as Earth. Also, there is now no need to introduce the unsupported notion of Lunarian colonies on either planet; either way, it would pose the same question.

  "And finally, an unsolved riddle of oceanography makes sense in this light, too. Research into tidal motions has shown that catastrophic upheavals on a planetary scale occurred on Earth at about this time, resulting in an abrupt increase in the length of the day and an increase in the rate at which the day is further being lengthened by tidal friction. Well, the arrival of Minerva's moon would certainly create enormous gravitational and tidal disturbances. Although the exact mechanics aren't too clear right now, it appears that the kinetic energy acquired by Minerva's moon as it fell toward the Sun, was absorbed in neutralizing part of the Earth's rotational energy, causing a longer day. Also, increased tidal friction since then is to be expected. Before the Moon appeared, Earth experienced only Solar tides, whereas from that time up until today, there have been both Solar and Lunar tides."

  Hunt showed his empty hand in a gesture of finality and pushed himself back in his chair. He straightened the pile of notes on the desk before going on to conclude:

  "That's it. As I said earlier, at this stage it represents no more than a hypothesis that accounts for all the facts. But there are some things we can do toward testing the truth of it.

  "For a start, we have a large chunk of Minerva piled up all over Farside. The recent material is so like the original Lunar material that it was years before anybody realized it had been added only recently. That supports the idea that the Moon and the meteorites originated in the same part of the Solar System. I'd like to suggest that we perform detailed comparisons between data from Farside material and data from the Asteroid surveys. If the results indicate that they are both the same kind of stuff and appear to have come from the same place, the whole idea
would be well supported.

  "Another thing that needs further work is a mathematical model of the process of mutual capture between Earth and Luna. We know quite a lot about the initial conditions that must have existed before and, of course, a lot more about the conditions that exist now. It would be reassuring to know that for the equations involved there exist solutions that allow one situation to transform into the other within the normal laws of physics. At least, it would be nice to prove that the whole idea isn't impossible.

  "Finally, of course, there is the Ganymean ship here. Without doubt a lot of new information is waiting to be discovered—far more than we've had to work on so far. I'm hoping that somewhere in the ship there will be astronomic data to tell us something about the Solar System at the time of the Ganymeans. If, for example, we could determine whether or not the third planet from the Sun of their Solar System had a satellite, or if we could learn enough about their moon to identify it as Luna—perhaps by recognizing Nearside surface features—then the whole theory would be well on the way to being proved.