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 L's 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 didn't 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. Steinfield's 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 isn't evenly distributed," Steinfield said, waving toward the model. "It's a lot thicker on Farside than on Nearside—something 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 there's no obvious reason," Hunt mused.

Steinfield's flailing arm continued to describe wild circles around the sphere in front of them. "There's no reason for the crust to solidify a lot thicker on one side, sure, but that doesn't really matter, because that's 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 back—one hell of a lot younger! But you know that—that's why you're here."

"You don't mean it was formed recently," Hunt stated.