The Apollo Seventeen Mission, in December 1972, had marked the successful conclusion to mans first concerted effort to reach and explore first-hand a world other than his own. After the Apollo program, NASA activities were restricted, mainly as a result of the financial pressures exerted on the USA by the economic recessions that came and went across the Western world throughout that decade, by the politically inspired oil crisis and various other crises manufactured in the Middle East and the lower half of Africa, and by the promotion of the Vietnam War. During the mid and late seventies, a succession of unmanned probes were dispatched to Mars, Venus, Mercury, and some of the outer planets. When manned missions were resumed in the 1980s, they focused on the development of various types of space shuttle and on the construction of permanently manned orbiting laboratories and observatories, the main objective being the consolidation of a firm jumping-off point prior to resumed expansion outward. Thus, for a period, the Moon was left once more on its own, free to continue its billion-year contemplation of the Universe without further interruption by man.
The information brought back by the Apollo astronauts finally resolved the conflicting speculations concerning the Moons nature and origins that had been mooted by generations of Earth-bound observers. Soon after the Solar System was formed, 4,500 million years ago, give or take a few, the Moon became molten to a considerable depth, possibly halfway to the center; the heat was generated by the release of gravitational energy as the Moon continued to accumulate. During the cooling that followed, the heavier, iron-bearing minerals sank toward the interior, while the less dense, aluminum-rich ones floated to the surface to form the highland crust. Continual bombardment by meteorites stirred up the mixture and complicated the process to some degree but by 4,300 million years ago the formation of the crust was virtually complete. The bombardment continued until 3,900 million years ago, by which time most of the familiar surface features already existed. From then until 3,200 million years ago, basaltic lavas flowed from the interior, induced in some places by remelting due to concentrations of radioactive heat sources below the surface, to fill in the impact basins and create the darker maria. The crust continued cooling to greater depths until molten material could no longer penetrate. Thereafter, all remained unchanging through the ages. Occasionally an additional impact crater appeared and falling dust gradually eroded the top millimeter of surface, but essentially, the Moon became a dead planet.
This history came from detailed observations and limited explorations of Nearside. Orbital observations of Farside suggested that much of the same story applied there also, and since this sequence was consistent with existing theory, nobody doubted its validity for many years after Apollo. Of course, details remained to be added, but the broad picture was convincingly clear. However, when man returned to the Moon in strength and to stay, ground exploration of Farside threw up a completely different and totally unexpected story.
Although the surface of Farside looked much the same as Nearside to the distant observer, it proved at the microscopic level to have undergone something radically different in its history. Furthermore, as bases, launch sites, communications installations, and all the other paraphernalia that accompanied man wherever he went, began proliferating on Nearside, the methodical surface coverage that this entailed produced oddities there, too.
All the experiments performed on the rock samples brought back from the eight sites explored before the mid-seventies gave consistent results supporting the orthodox theories. When the number of sites grew to thousands, by far the majority of additional data confirmed thembut some curious exceptions were noted, exceptions which seemed to indicate that some of the features on Nearside ought, rightfully, to be on Farside.
None of the explanations hazarded were really conclusive. This made little difference to the executives and officers of UNSA, since by that time the pattern of Lunar activity had progressed from that of pure scientific research to one of intense engineering operations. Only the academic fraternity of a few universities found time to ponder and correspond on the spectral inconsistencies between dust samples. So for many years the well-documented problem of "lunar hemispheric anomalies" remained filed, along with a million and one other items, in the "Awaiting Explanation" drawer of science.
A methodical review of the current state of knowledge in any branch of science that might have a bearing on the Lunarian problem was a routine part of Group Ls business. Anything to do with the Moon was, naturally, high on the list of things to check up on, and soon the group had amassed enough information to start a small library on the subject. Two junior physicists, who didnt duck quickly enough when Hunt was giving out assignments, were charged with the Herculean task of sifting through all this data. It took some time for them to get around to the topic of hemispheric anomalies. When they did, they found reports of a series of dating experiments performed some years previously by a nucleologist named Kronski at the Max Planck Institute in Berlin. The data that appeared in those reports caused the two physicists to drop everything and seek out Hunt immediately.
After a long discussion, Hunt made a vi-phone call to a Dr. Saul Steinfield of the Department of Physics of the University of Nebraska, who specialized in Lunar phenomena. As a consequence of that call, Hunt made arrangements for the deputy head of Group L to take charge for a few days, and he flew north to Omaha early the next morning. Steinflelds secretary met Hunt at the airport, and within an hour Hunt was standing in one of the physics department laboratories, contemplating a three-foot-diameter model of the Moon.
"The crust isnt evenly distributed," Steinfield said, waving toward the model. "Its a lot thicker on Farside than on Nearsidesomething that has been known for a long time, ever since the first artificial satellites were hung around the Moon in the nineteen sixties. The center of mass is about two kilometers away from the geometric center."
"And theres no obvious reason," Hunt mused.
Steinflelds flailing arm continued to describe wild circles around the sphere in front of them. "Theres no reason for the crust to solidify a lot thicker on one side, sure, but that doesnt really matter, because thats not the way it happened. The material that makes up the Farside surface is much younger than anything anybody ever believed existed on the Moon in any quantity up until about, ah, thirty or so years backone hell of a lot younger! But you know thatthats why youre here."
"You dont mean it was formed recently," Hunt stated.
Steinfield shook his head vigorously from side to side, causing the two tufts of white hair that jutted from the sides of his otherwise smooth head to wave about in a frenzy. "No. We can tell that its about as old as the rest of the Solar System. What I mean isit hasnt been where it is very long."
He caught Hunts shoulder and half turned him to face a wall chart showing a sectional view through the Lunar center. "You can see it on this. The red shell is the original outer crust going right aroundits roughly circular, as youd expect. On Farsideherethis blue stuff sits on top of it and wasnt added very long ago."
"On top of what used to be the surface."
"Exactly. Somebody dumped a couple of billion tons of junk down on the old crustbut only on this side."
"And thats been verified pretty conclusively?" Hunt asked, just to be doubly sure.
"Yeah. . . yeah. Enough bore holes and shafts have been sunk all over Farside to tell us pretty closely where the old surface was. Ill show you something over here . . ." A major section of the far wall comprised nothing but rows of small metal drawers, each with its own neatly lettered label, extending from floor to ceiling. Steinfield walked across the room, and stooped to scan the labels, at the same time mumbling to himself semi-intelligibly. With a sudden "Thats it!" he pounced on one of the drawers, opened it, and returned bearing a closed glass container about the size of a small pickle jar. It contained a coarse piece of a light gray rocky substance that glittered faintly in places, mounted on a wire support.
"This is a fairly common KREEP basalt from Farside. It"
"Creep?"
"Rich in potassiumthat is, Krare earth elements, and phosphorus: KREEP."
"OhI see."
"Compounds like this," Steinfield continued, "make up a lot of the highlands. This one solidified around 4.1 billion years ago. Now, by analyzing the isotope products produced by cosmic-ray exposure, we can tell how long its been lying on the surface. Again, the figure for this one comes out at about 4,100 million years."
Hunt looked slightly puzzled. "But thats normal. Its what youd expect, isnt it?"
"If it had been lying on the surface, yes. But this came from the bottom of a shaft over seven hundred feet deep! In other words, it was on the surface for all that timethen suddenly its seven hundred feet down." Steinfleld gestured toward the wall chart again. "As I said, we find the same thing all over Farside. We can estimate how far down the old surface used to be. Below it we find old rocks and structures that go way back, just like on Nearside; above it everythings a messthe rock all got pounded up and lots of melting took place when the garbage came down, all the way up to whats now the surface. Its what youd expect."
Hunt nodded his agreement. The energy released by that amount of mass being stopped dead in its tracks would have been phenomenal.
"And nobody knows where it came from?" he asked.
Steinfield repeated his head-shaking act. "Some people say that a big meteorite shower must have got in the way of the Moon. That may be trueits never been argued conclusively one way or the other. The composition of the garbage isnt really like a lot of meteorites, thoughits closer to the Moon itself. Its as if they were made out of the same stuffthats why it looks the same from higher up. You have to look at the microstructure to see the things Ive been talking about."
Hunt examined the specimen curiously for a while in silence. At length he laid it carefully on the top of one of the benches. Steinfield picked it up and returned it to its drawer.
"Okay," Hunt said as Steinfield rejoined him. "Now, what about the Farside surface?"
"Kronski and company."
"Yesas we discussed yesterday."
"The Farside surface craters were made by the tail end of the garbage-dumping process, unlike the Nearside craters, which came from meteorite impacts oh. . . a few billion years back. In rock samples from around the rims of Farside craters we find that things like the activity levels of long half-life elements are very lowfor instance, aluminum twenty-six and chlorine thirty-six; also the rates of absorption of hydrogen, helium, and inert gases from the Solar wind. Things like that tell us that those rocks havent been lying there very long; and since they got where they were by being thrown out of the craters, the craters havent been there very long, either." Steinfield made an exaggerated empty-handed gesture. "The rest you know. People like Kronski have done all the figuring and put them at around fifty thousand years oldyesterday!" He waited for a few seconds. "There must be a Lunarian connection somewhere. The number sounds like too much of a coincidence to me."
Hunt frowned for a while and studied the detail of the Farside hemisphere of the model. "And yet, you must have known about all this for years," he said, looking up. "Why the devil did you wait for us to call you?"
Steinfield showed his hands again and held the pose for a second or two. "Well, you UNSA people are pretty smart cookies. I figured you already knew about all this."
"We should have picked it up sooner, I admit," Hunt agreed. "But weve been rather busy."
"Guess so," Steinfield murmured. "Anyhow, theres even more to it. Ive told you all the consistent things. Now Ill tell you some of the funny things. . . ." He broke off as if just struck by a new thought. "Ill tell you about the funny things in a second. How about a cup of coffee?"
"Great."
Steinfield lit a Bunsen burner, filled a large laboratory beaker from the nearest tap, and positioned it on a tripod over the flame. Then he squatted down to rummage in the cupboard beneath the bench and at last emerged triumphantly with two battered enamel mugs.
"First funny thing: The distribution of samples that we dig up on Farside that have a history of recent radioactive exposure doesnt match the distribution or strength of the activity sources. There ought to be sources clustered in places where there arent."
"How about the meteorite storm including some, highly active meteorites?" Hunt suggested.
"No, wont wash," Steinfield answered, looking along a shelf of glass jars and eventually selecting one that contained a reddish-brown powder and was labeled "Ferric Oxide." "If there were meteorites like that, bits of them should still be around. But the distribution of active elements in the garbage is pretty evenabout normal for most rocks." He began spooning the powder into the mugs. Hunt inclined his head apprehensively in the direction of the jar.
"Coffee doesnt seem to last long around here if you leave it lying around in coffee jars," Steinfield explained. He nodded toward a door that led into the room next-door and bore the sign "RESEARCH STUDENTS." Hunt nodded understandingly.
"Vaporized?" Hunt tried.
Again Steinfield shook his head.
"In that case they wouldnt have been in proximity to the rock long enough to produce the effects observed." He opened another jar marked "Disodium Hydrogen Phosphate." "Sugar?"
"Second funny thing," Steinfield continued. "Heat balance. We know how much mass came down, and from the way it fell, we can figure its kinetic energy. We also know from statistical sampling how much energy needed to be dissipated to account for the melting and structural deformations; also, we know how much energy gets produced by underground radioactivity and where. Problem: The equations dont balance; youd need more energy to make what happened happen than there was available. So, where did the extra come from? The computer models of this are very complex and there could be errors in them, but thats the way it looks right now."
Steinfield allowed Hunt to digest this while he picked up the beaker with a pair of tongs and proceeded to fill the mugs. Having safely completed this operation, he began filling his pipe, still silent.
"Any more?" Hunt asked at last, reaching for his own cigarette case.
Steinfield nodded affirmatively. "Nearside exceptions. Most of the Nearside craters fit with the classic model: old. However, there are some scattered around that dont fit the pattern; cosmic-ray dating puts them at approximately the same age as those on Farside. The usual explanation is that some strays from the recent Farside bombardment overshot around to the Nearside. . ." He shrugged. "But there are peculiarities in some instances that dont really support that."
"Like?"
"Like some of the glasses and breccia formations show heating patterns that arent consistent with recent impact . . . Ill show you what I mean later."
Hunt turned this new information over in his mind as he lit a cigarette and sipped his drink. It tasted like coffee, anyway.
"And thats the last funny thing?"
"Yep, thats about the broad outline. No, wait a minutelast funny thing plus one. How come none of the meteorites in the shower hit Earth? Plenty of eroded remains of terrestrial meteorite craters have been identified and dated. All the computer simulations say that there should be a peak of abnormal activity at around this time, judging from how big the heap of crud that hit the Moon must have been. But there arent any signs of one, even allowing for the effects of the atmosphere."
Hunt and Steinfield spent the rest of that day and all of the next sifting through figures and research reports that went back many years. Hunt did not sleep at all during the following night, but smoked a pack of cigarettes and consumed a gallon of coffee while he stared at the walls of his hotel room and twisted the new information into every contortion his mind could devise.
Fifty thousand years ago the Lunarians were on the Moon. Where they came from didnt really matter for the time being; that was another question. At about the same time an intense meteorite storm obliterated the Farside surface. Did the storm wipe out the Lunarians on the Moon? Possiblybut that wouldnt have had any effect on them back on whatever planet they had come from. If all the UNSA people on Luna were wiped out, it wouldnt make any lasting difference to Earth. So, what happened to the rest of the Lunarians? Why hadnt anybody seen them since? Had something else happened to them that was more widespread than whatever happened on the Moon? Could the something else have caused the meteorite storm? Could a second something else have both caused the first and extinguished the Lunarians in other places? Perhaps there was no connection? Unlikely.
Then there were the inconsistencies that Steinfield had talked about. . . . An absurd idea came from nowhere, which Hunt rejected impatiently. But as the night wore on, it kept coming back again with growing insistence. Over breakfast he decided that he had to know the story that lay below those billions of tons of rubble. There had to be some way of extracting enough information to reconstruct the characteristics of the surface just before the bombardment commenced. He put the question to Steinfield later on that morning, back in the lab.
Steinfield shook his head firmly. We tried for over a year to make a picture like that. We had twelve programmers working on it. They got nowhere. Its too much of a mess down thereall ploughed up. All you get is garbage."
"How about a partial picture?" Hunt persisted. Was there any way that a contour map could be calculated, showing just the distribution of radiation sources immediately prior to the bombardment?
"We tried that, too. You do get a degree of statistical clustering, yes. But theres no way we could tell where each individual sample was when it got irradiated. They would have been thrown miles by the impacts; a lot of them would have been bounced all over the place by repeat impacts. Nobody ever built a computer that could unscramble all that entropy. Youre up against the second law of thermodynamics; if you ever built one, it wouldnt be a computer at allit would be a refrigerator."
"What about a chemical approach? What techniques are available that might reveal where the prebombardment craters were? Could their ghosts still be detected a thousand feet down below the surface?"
"No way!"
"There has to be some way of reconstructing what the surface used to look like."
"Did you ever try reconstructing a cow from a truckload of hamburger?"
They talked about it for another two days and into the nights at Steinfields home and Hunts hotel. Hunt told Steinfield why he needed the information. Steinfield told Hunt he was crazy. Then one morning, back at the laboratory, Hunt exclaimed, "The Nearside exceptions!"
"Huh?"
"The Nearside craters that date from the time of the storm. Some of them could be right from the beginning of it."
"So?"
"They didnt get buried like the first craters on Farside. Theyre intact."
"Surebut they wont tell you anything new. Theyre from recent impacts, same as everything thats on the surface of Farside."
"But you said some of them showed radiation anomalies. Thats just what I want to know more about."
"But nobody ever found any suggestion of what youre talking about."
"Maybe they werent looking for the right things. They never had any reason to."
The physics department had a comprehensive collection of Lunar rock samples, a sizeable proportion of which comprised specimens from the interiors and vicinities of the young, anomalous craters on Nearside. Under Hunts persistent coercion, Steinfleld agreed to conduct a specially devised series of tests on them. He estimated that he would need a month to complete the work.
Hunt returned to Houston to catch up on developments there and a month later flew back to Omaha. Steinfields experiments had resulted in a series of computer-generated maps showing anomalous Nearside craters. The craters divided themselves into two classes on the maps: those with characteristic irradiation patterns and those without.
"And another thing," Steinfield informed him. "The first class, those that show the pattern, have also got another thing in common that the second class hasnt got: glasses from the centers were formed by a different process. So now weve got anomalous anomalies on Nearside, too!"
Hunt spent a week in Omaha and then went directly to Washington to talk to a group of government scientists and to study the archives of a department that had ceased to exist more than fifteen years before. He then returned to Omaha once again and showed his findings to Steinfleld. Steinfield persuaded the university authorities to allow selected samples from their collection to be loaned to the UNSA Mineralogy and Petrology Laboratories in Pasadena, California, for further testing of an extremely specialized nature, suitable equipment for which existed at only a few establishments in the world.
As a direct consequence of these tests, Caldwell authorized the issue of a top-priority directive to the UNSA bases at Tycho, Crisium, and some other Lunar locations, to conduct specific surveys in the areas of certain selected craters. A month after that, the first samples began arriving at Houston and were forwarded immediately to Pasadena; so were the large numbers of samples collected from deep below the surface of Farside.
The outcome of all this activity was summarized in a memorandum stamped "SECRET" and written on the anniversary of Hunts first arrival in Houston.
(1) Hemispheric Anomalies
For many years, radical differences have been known to exist
between the nature and origins of Lunar Nearside and Farside
surface features.
(a) Nearside
Original Lunar surface from 4 billion years ago. Nearly all surface
cratering caused by explosive release of kinetic energy by
meteorite impacts. Some youngere.g., Copernicus, 850 million
years old.
(b) Farside
Surface comprises large mass of recently added material to average
depth circa 300 meters. Craters formed during final phase of this
bombardment. Dating of these events coincides with Lunarian
presence. Origin of bornbardment uncertain.
(2) Nearside Exceptions
Known for approx. the last thirty years that some Nearside craters
date from same period as those on Farside. Current theory ascribes
them to overshoots from Parside bombardment.
(3) Conclusion From Recent Research
at Omaha and Pasadena
All Nearside exceptions previously attributed to meteoritic
impacts. This belief now considered incorrect. Two classes of
exceptions now distinguished:
(a) Class I Exceptions
Confirmed as meteoritic impacts occurring 50,000 years ago.
(b) Class II Exceptions Differing from Class I in irradiation
history, formation of glasses, absence of impact corroboration and
positive results to tests for elements hyperium, bonnevilliuin,
genevium. Example: Crater Lunar Catalogue reference MB 3076/K2/E
currently classed as meteoritic. Classification erroneous. Crater
MB 3076/K2/E was made by a nucleonic bomb. Other cases confirmed.
Investigations continuing.
(4) Farside Subsurface
Intensive sampling from depths approximating that of the original
crust indicate widespread nucleonic detonations prior to meteorite
bombardment. Thermonuclear and fission reactions also suspected but
impossible to confirm.
(5) Implications
(a) Sophisticated weapons used on Luna at or near time of
Lunarian presence, mainly on Farside. Lunarian involvement implied
but not proved.
(b) If Lunarians involved, possibility of more widespread
conflict embracing Lunarian home planet. Possible cause of Lunarian
extinction.
(c) Charlie was a member of more than a small, isolated expedition to our Moon. A significant Lunarian presence on the Moon is indicated. Mainly concentrated on Farside. Practically all traces since obliterated by meteorite storm.