here any more than on Earth, and I suppose they convinced themselves, more or less, that whatever I had said to them was just a meaningless guess. But Barron knew, of course.”
“I see.” Denison paused.
Selene’s lips twitched. “Somehow I get the feeling that you want to say: ‘Oh, that’s why he bothers with you.’ ”
“No, of course not, Selene. You’re quite attractive enough to be desired for your own sake.”
“I think so, too, but every little bit helps and Barron was bound to be interested in my Intuitionism. Why shouldn’t he be? Only he insisted I keep my job as tourist guide. He said I was an important natural resource of the Moon and he didn’t want Earth monopolizing me the way they monopolized the synchrotron.”
“An odd thought. But perhaps it was that the fewer who knew of your Intuitionism, the fewer would suspect your contribution to what would otherwise be put to his sole credit.”
“Now you sound like Barron yourself!”
“Do I? And is it possible he gets rather annoyed with you when your Intuitionism is working particularly well.”
Selene shrugged. “Barron is a suspicious man. We all have our faults.”
“Is it wise to be alone with me, then?”
Selene said, sharply, “Now don’t get hurt because I defend him. He doesn’t really suspect the possibility of sexual misbehavior between us. You’re from Earth. In fact, I might as well tell you he encourages our companionship. He thinks I can learn from you.”
“And have you?” asked Denison, coldly.
“I have.… Yet though that may be his chief reason for encouraging our friendship, it isn’t mine.”
“What’s yours?”
“As you well know,” said Selene, “and as you want to hear me say, I enjoy your company. Otherwise, I could get what I want in considerably less time.”
“All right, Selene. Friends?”
“Friends! Absolutely.”
“What have you learned from me, then? May I know?”
“That would take awhile to explain. You know that the reason we can’t set up a Pump Station anywhere we want to is that we can’t locate the para-Universe, even though they can locate us. That might be because they are much more intelligent or much more technologically advanced than we are—”
“Not necessarily the same thing,” muttered Denison.
“I know. That’s why I put in the ‘or.’ But it might also be that we are neither particularly stupid nor particularly backward. It might be something as simple as the fact that they offer the harder target. If the strong nuclear interaction is stronger in the para-Universe, they’d be bound to have much smaller Suns and, very likely, much smaller planets. Their individual world would be harder to locate than ours would be.
“Or then again,” she went on, “suppose it’s the electromagnetic field they detect. The electromagnetic field of a planet is much larger than the planet itself and is much easier to locate. And that would mean that while they can detect the Earth, they can’t detect the Moon, which has no electromagnetic field to speak of. That’s why, perhaps, we’ve failed to set up a Pump Station on the Moon. And, if their small planets lack a significant electromagnetic field, we can’t locate them.”
Denison said, “It’s an attractive thought.”
“Next, consider the inter-Universal exchange in properties that serves to weaken their strong nuclear interaction, cooling their Suns, while strengthening ours, heating and exploding our Suns. What might that imply? Suppose they can collect energy one-way without our help but only at ruinously low efficiencies. Under ordinary circumstances that would therefore be utterly impractical. They would need us to help direct concentrated energy in their direction by supplying tungsten-186 to them and accepting plutonium-186 in return. But suppose our Galactic arm implodes into a quasar. That would produce an energy concentration in the neighborhood of the Solar system enormously greater than now exists and one that might persist for over a million years.
“Once that quasar forms, even a ruinously low efficiency becomes sufficient. It wouldn’t matter to them, therefore, whether we are destroyed or not. In fact, we might argue that it would be safer for them if we did explode. Until we do, we might end the Pump for any of a variety of reasons and they would be helpless to start it again. After the explosion, they are home free; no one could interfere.… And that’s why people who say, ‘If the Pump is so dangerous, why don’t those terribly clever para-men stop it?’ don’t know what they’re talking about.”
“Did Neville give you that argument?”
“Yes, he did.”
“But the para-Sun would keep cooling down, wouldn’t it?”