across several hundred square kilometers of the Sea, and had found absolutely nothing.
Over the suit intercom, the driver was talking to his companion.
"What do you think happened to them, George? I don't believe they're here."
"Where else can they be? Kidnaped by Outsiders?"
"I'm almost ready to buy that" was the half-serious answer. Sooner or later, all astronauts believed, the human race would meet intelligences from elsewhere. That meeting might still be far in the future but meanwhile, the hypothetical "Outsiders" were part of the mythology of space, and got the blame for everything that could not be explained in any other way.
It was easy to believe in them when you were with a mere handful of companions on some strange, hostile world where the very rocks and air (if there was air) were completely alien. Then, nothing could be taken for granted, and the experience of a thousand Earth-bound generations might be useless. As ancient man had peopled the unknown around him with gods and spirits, so Homo astronauticus looked over his shoulder when he landed upon each new world, wondering who or what was there already. For a few brief centuries, Man had imagined himself the lord of the Universe, and those primeval hopes and fears had been buried in his subconscious. But now they were stronger than ever, and with good reason, as he looked into the shining face of the heavens and thought of the power and knowledge that must be lurking there.
"Better report to Base," said George. "We've covered our area, and there's no point in going over it again. Not until sunrise, anyway. We'll have a much better chance of finding something then. This damned earthlight gives me the creeps."
He switched on the radio, and gave the ski's call sign.
"Duster Two calling Traffic Control. Over."
"Port Roris Traffic Control here. Found anything?"
"Not a trace. What's new from your end?"
"We don't think she's out in the Sea. The Chief Engineer wants to speak to you."
"Right; put him on."
"Hello, Duster Two. Lawrence here. Plato Observatory's just reported a quake near the Mountains of Inaccessibility. It took place at nineteen thirty-five, which is near enough the time when Selene should have been in Crater Lake. They suggest she's been caught in an avalanche somewhere in that area. So head for the mountains and see if you can spot any recent slides or rockfalls."
"What's the chance, sir," asked the dust-ski pilot anxiously, "that there may be more quakes?"
"Very small, according to the Observatory. They say it will be thousands of years before anything like this happens again, now that the stresses have been relieved."
"I hope they're right. I'll radio when I get to Crater Lake; that should be in about twenty minutes."
But it was only fifteen minutes before Duster Two destroyed the last hopes of the waiting listeners.
"Duster Two calling. This is it, I'm afraid. I've not reached Crater Lake yet; I'm still heading up the gorge. But the Observatory was right about the quake. There have been several slides, and we had difficulty in getting past some of them. There must be ten thousand tons of rock in the one I'm looking at now. If Selene's under that lot, we'll never find her. And it won't be worth the trouble of looking."
The silence in Traffic Control lasted so long that the ski called back: "Hello, Traffic Control - did you receive me?"
"Receiving you," said the Chief Engineer in a tired voice. "See if you can find some trace of them. I'll send Duster One in to help. Are you sure there's no chance of digging them out?"
"It might take weeks, even if we could locate them. I saw one slide three hundred meters long. If you tried to dig, the rock would probably start moving again."
"Be very careful. Report every fifteen minutes, whether you find anything or not."
Lawrence turned away from the microphone, physically and mentally exhausted. There was nothing more that he could do - or, he suspected, that anyone could do. Trying to compose his thoughts, he walked over to the southward-facing observation window, and stared into the face of the crescent Earth.
It was hard to believe that she was fixed there in the southern sky, that though she hung so close to the horizon, she would neither rise nor set in a million years. However long one lived here, one never really accepted this fact, which violated all the racial wisdom of mankind.
On the other side of that gulf (already so small to a generation that had