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.'
'Yes-as 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 low-for 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 haven’t been lying there very long; and since they got where they were by being thrown out of the craters, the craters haven’t 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 old-yesterday!' 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 we’ve been rather busy.'
'Guess so,' Steinfield murmured. 'Anyhow, there’s even more to it. I’ve told you all the consistent things. Now I’ll tell you some of the funny things…' He broke off as if just struck by a new thought. 'I’ll 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 doesn’t match the distribution or strength of the activity sources. There ought to be sources clustered in places where there aren’t.'
'How about the meteorite storm including some, highly active meteorites?' Hunt suggested.
'No, won’t 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 even-about normal for most rocks.' He began spooning the powder into the mugs. Hunt inclined his head apprehensively in the direction of the jar.
'Coffee doesn’t 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 wouldn’t 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 don’t balance; you’d 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 that’s 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 don’t 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 don’t really support that.'
'Like?'
'Like some of the glasses and breccia formations show heating patterns that aren’t consistent with recent impact… I’ll 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 that’s the last funny thing?'
'Yep, that’s about the broad outline. No, wait a minute-last 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 aren’t 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 didn’t 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? Possibly-but that wouldn’t 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 wouldn’t make any lasting difference to Earth. So, what happened to the rest of the Lunarians? Why hadn’t 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. It’s too much of a mess down there-all 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 there’s 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. You’re up against the second law of thermodynamics; if you ever built one, it wouldn’t be a computer at all-it 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 Steinfield’s home and Hunt’s hotel. Hunt told
