"You can do better than that. Suppose I suggest that you learned of Gaia only in the last couple of years."
Trevize peered in Pelorat's direction, felt the absence of any ability to read an unseen expression in the dimness, and raised the light level of the room a bit. The glory of the representation of the night sky on the screen dimmed in proportion. Pelorat's expression was stony and revealed nothing.
"Well?" said Trevize.
"I'm thinking," said Pelorat mildly. "You may be right. I wouldn't swear to it. When I wrote Jimbor of Ledbet University, I didn't mention Gaia, though in that case it would have been appropriate to do so, and that was in - let's see - in - and that was three years ago. I think you're right, Golan."
"And how did you come upon it?" asked Trevize. "In a communication? A book? A scientific paper? Some ancient song? How? - Come on!"
Pelorat sat back and crossed his arms. He fell into deep thought and didn't move. Trevize said nothing and waited.
Finally Pelorat said, "In a private communication. - But it's no use asking me from whom, my dear chap. I don't remember."
Trevize moved his hands over his sash. They felt clammy as he continued his efforts to elicit information without too clearly forcing words into the other's mouth. He said, "From a historian? From an expert in mythology? From a Gaiactographer?"
"No use. I cannot match a name to the communication."
"Because, perhaps, there was none."
"Oh no. That scarcely seems possible."
"Why? Would you have rejected an anonymous communication?"
"I suppose not."
"Did you ever receive any?"
"Once in a long while. In recent years, I had become well known in certain academic circles as a collector of particular types of myths and legends and some of my correspondents were occasionally kind enough to forward material they had picked up from nonacademic sources. Sometimes these might not be attributed to anyone in particular."
Trevize said, "Yes, but did you ever receive anonymous information directly, and not by way of some academic correspondent?"
"That sometimes happened - but very rarely."
"And can you be certain that this was not so in the case of Gaia?"
"Such anonymous communications took place so rarely that I should think I would remember if it had happened in this case. Still, I can't say certainly that the information was not of anonymous origin. Mind, though, that's not to say that I did receive the information from an anonymous source."
"I realize that. But it remains a possibility, doesn't it?"
Pelorat said, very reluctantly, "I suppose it does. But what's all this about?"
"I'm not finished," said Trevize peremptorily. "Where did you get the information from - anonymous or not? What world?"
Pelorat shrugged. "Come now, I haven't the slightest idea."
"Could it possibly have been from Sayshell?"
"I told you. I don't know."
"I'm suggesting you did get it from Sayshell."
"You can suggest all you wish, but that does not necessarily make it so."
"No? When Quintesetz pointed out the dim Star at the center of the Five Sisters, you knew at once it was Gaia. You said so later on to Quintesetz, identifying it before he did. Do you remember?"
"Yes, of course."
"How was that possible? How did you recognize at once that the dim star was Gaia?"
"Because in the material I had on Gaia, it was rarely referred to by that name. Euphemisms were common, many different ones. One of the euphemisms, several times repeated, was 'the little Brother of the Five Sisters. ' Another was 'the Pentagon's Center' and sometimes it was called 'o Pentagon. ' When Quintesetz pointed out the Five Sisters and the central star, the allusions came irresistibly to mind."
"You never mentioned those allusions to me earlier."
"I didn't know what they meant and I didn't think it would have been important to discuss the matter with you, who were a..." Pelorat hesitated.
"A nonspecialist?"
"You realize, I hope, that the pentagon of the Five Sisters is an entirely relative form."
"What do you mean?"
Trevize laughed affectionately. "You surface worm. Do you think the sky has an objective shape of its own? That the stars are nailed in place? The pentagon has the shape it has from the surface of the worlds of the planetary system to which Sayshell Planet belongs - and from there only. From a planet circling any other star, the appearance of the Five Sisters is different. They are seen from a different angle, for one thing. For another, the five stars of the pentagon are at different distances from Sayshell and, seen from other angles, there could be no visible relationship among them at all. One or two stars might be in one half of the sky, the others in the other half. See here..."
Trevize darkened the room again and leaned over the computer. "There are eighty-six populated planetary systems making up the Sayshell Union. Let us keep Gaia - or the spot where Gaia ought to be - in place" (as he said that, a small red circle appeared in the center of the pentagon of the Five Sisters) "and shift to the skies as seen from any of the other eighty-six worlds taken at random."
The sky shifted and Pelorat blinked. The small red circle remained at the center of the screen, but the Five Sisters had disappeared. There were bright stars in the neighborhood but no tight pentagon. Again the sky shifted, and again, and again. It went on shifting. The red circle remained in place always, but at no time did a small pentagon of equally bright stars appear. Sometimes what might be a distorted pentagon of stars - unequally bright - appeared, but nothing like the beautiful asterism Quintesetz had pointed out.