Foundation and Earth - Isaac Asimov [134]
“We’ll be landing tomorrow,” said Trevize cheerfully.
“This planet we’re approaching doesn’t have an ocean.”
“Only some thin polar ice caps.”
“Or much of an atmosphere.”
“Only a hundredth the density of the atmosphere on Terminus.”
“Or life.”
“Nothing I can detect.”
“Then what could have eroded away the craters?”
“An ocean, an atmosphere, and life,” said Trevize. “Look, if this planet had been airless and waterless from the start, any craters that had been formed would still exist and the whole surface would be cratered. The absence of craters proves it can’t have been airless and waterless from the start, and may even have had a sizable atmosphere and ocean in the near past. Besides, there are huge basins, visible on this world, that must have held seas and oceans once, to say nothing of the marks of rivers that are now dry. So you see there was erosion and that erosion has ceased so short a time ago, that new cratering has not yet had time to accumulate.”
Pelorat looked doubtful. “I may not be a planetologist, but it seems to me that if a planet is large enough to hang on to a dense atmosphere for perhaps billions of years, it isn’t going to suddenly lose it, is it?”
“I shouldn’t think so,” said Trevize. “But this world undoubtedly held life before its atmosphere vanished, probably human life. My guess is that it was a terraformed world as almost all the human-inhabited worlds of the Galaxy are. The trouble is that we don’t really know what its condition was before human life arrived, or what was done to it in order to make it comfortable for human beings, or under what conditions, actually, life vanished. There may have been a catastrophe that sucked off the atmosphere and that brought about the end of human life. Or there may have been some strange imbalance on this planet that human beings controlled as long as they were here and that went into a vicious cycle of atmospheric reduction once they were gone. Maybe we’ll find the answer when we land, or maybe we won’t. It doesn’t matter.”
“But surely neither does it matter if there was life here once, if there isn’t now. What’s the difference if a planet has always been uninhabitable, or is only uninhabitable now?”
“If it is only uninhabitable now, there will be ruins of the one-time inhabitants.”
“There were ruins on Aurora—”
“Exactly, but on Aurora there had been twenty thousand years of rain and snow, freezing and thawing, wind and temperature change. And there was also life—don’t forget life. There may not have been human beings there, but there was plenty of life. Ruins can be eroded just as craters can. Faster. And in twenty thousand years, not enough was left to do us any good. —Here on this planet, however, there has been a passage of time, perhaps twenty thousand years, perhaps less, without wind, or storm, or life. There has been temperature change, I admit, but that’s all. The ruins will be in good shape.”
“Unless,” murmured Pelorat doubtfully, “there are no ruins. Is it possible that there was never any life on the planet, or never any human life at any rate, and that the loss of the atmosphere was due to some event that human beings had nothing to do with?”
“No, no,” said Trevize. “You can’t turn pessimist on me, because it won’t work. Even from here, I’ve spotted the remains of what I’m sure was a city. —So we land tomorrow.”
65.
BLISS SAID, IN A WORRIED TONE, “FALLOM IS CONVINCED we’re going to take her back to Jemby, her robot.”
“Umm,” said Trevize, studying the surface of the world as it slid back under the drifting ship. Then he looked up as though he had heard the remark only after a delay. “Well, it was the only parent she knew, wasn’t it?”
“Yes, of course, but she thinks we’ve come back to Solaria.”
“Does it look like Solaria?”
“How would she know?”
“Tell her it’s not Solaria. Look, I’ll give you one or two reference book-films with graphic illustrations. Show her close-ups of a number of different inhabited worlds and explain that