"So I thought in the beginning. But much is possible here. That shaft, for instance. The Selenites have its weight almost completely nullified with anti-gravity forces. They know something, the devils."
"But the sun, or whatever it is, isn't pictured central. In fact, it seems to contact one side of the moon's central cavity."
"Naturally. That's why the same face of Luna is always towards Earth; it's on the heavy side, of course. Here, sit down, Bill."
Peterson indicated a chair, which Bonwitt took. "And," continued the ex-super, "that sun, as you call it and as it properly is, can be shifted from normal position. That's what was done last night; that's why Luna shifted on her axis. A test. I knew, of course, but pretended ignorance back on the other side. Now you're in it, I can tell you.
"The brown men are native to the moon but not to our solar system. Their ancestors inhabited the body's surface when it had an atmosphere and was warm in the light of a distant sun. They burrowed when they learned their planet was to be hurled into space by a cataclysm which was to break up its solar system. And when, in the distant past, their world was captured by ours as a satellite, they had to remain beneath the surface. They burrowed deeper, found this inner realm, this world within a world. The inner sun then was still quite hot; it yet holds nearly enough heat for their comfort and sustenance.
"Through countless ages, this race has been dissatisfied. They wanted to live outside as did their forbears, but could only go to the surface in space-suits. They began planning a migration to Earth. The huge motor, the shaft, the crater, are the results. The means."
"To migrate?" Bonwitt was incredulous.
"Yes."
"Peaceful, or warlike, this migration?"
"They plan peace if possible, war if necessary."