"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.