“I think I can reproduce enough of it now so that our people can fill it in.”

“All right, then. Let’s get started.”

“Not yet. Oh, damn it, Barron, not yet.”

“Why not yet?”

“We need the energy, too.”

“But we have that.”

“Not quite. The leak-point is unstable; pretty badly unstable.”

“But that can be fixed up. You said so.”

“I said I thought it could.”

“That’s good enough for me.”

“Just the same, it would be better to have Ben work out the details and stabilize it.”

There was a silence between them. Neville’s’ thin face slowly twisted into something approaching hostility. “You don’t think I can do it? Is that it?”

Selene said, “Will you come out on the surface with me and work on it?”

There was another silence. Neville said, unsteadily, “I don’t appreciate your sarcasm. And I don’t want to have to wait long.”

“I can’t command the laws of nature. But I think it won’t be long.... Now if you don’t mind, I need my sleep. I’ve got my tourists tomorrow.”

For a moment, Neville seemed on the point of gesturing to his own bed-alcove as though offering hospitality, but the gesture, if that was what it was, did not really come to birth and Selene made no sign of understanding or even anticipating. She nodded wearily, and left.

“I had hoped, to be frank,” said Gottstein, smiling over what passed for dessert—a sticky, sweet concoction— “that we would have seen each other more often.”

Denison said, “It is kind of you to take such an interest in my work. If the leak-instability can be corrected, I think my achievement—and that of Miss Lindstrom—will have been a most significant one.”

“You speak carefully, like a scientist. ... I won’t insult you by offering the Lunar equivalent of a liqueur; that is the one approximation to Earth’s cuisine I have simply made up my mind not to tolerate. Can you tell me, in lay language, what makes the achievement significant?”

“I can try,” said Denison, cautiously. “Suppose we start with the para-Universe. It has a more intense strong nuclear interaction than our Universe has so that relatively small masses of protons in the para-Universe can undergo the fusion reaction capable of supporting a star. Masses equivalent to our stars would explode violently in the para-Universe which has many more, but much smaller, stars than ours does.

“Suppose, now, that we had a much less intense strong nuclear interaction than that which prevails in our Universe. In that case, huge masses of protons would have so little tendency to fuse that a very large mass of hydrogen would be needed to support a star. Such an anti-para-Uni-verse—one that was the opposite of the para-Universe, in other words—would consist of considerably fewer but of far larger stars than our Universe does. In fact, if the strong nuclear interaction were made sufficiently weak, a Universe would exist which consisted of a single star containing all the mass in that Universe. It would be a very dense star, but relatively non-reactive and giving off no more radiation than our single Sun does, perhaps.”

Gottstein said, “Am I wrong, or isn’t that the situation that prevailed in our own Universe before the time of the big bang—one vast body containing all the universal mass.”

“Yes,” said Denison, “as a matter of fact, the anti-para-Universe I am picturing consists of what some call a cosmic egg; or ‘cosmeg’ for short. A cosmeg-Universe is what we need if we are to probe for one-way leakage. The para-Universe we are now using with its tiny stars is virtually empty space. You can probe and probe and touch nothing.”

“The para-men reached us, however.”

“Yes, possibly by following magnetic fields. There is some reason to think that there are no planetary magnetic fields of significance in the para-Universe, which deprives us of the advantage they have. On the other hand, if we probe the cosmeg-Universe, we cannot fail. The cosmeg is, itself, the entire Universe, and wherever we probe we strike matter.”

“But how do you probe for it?”

Denison hesitated. “That is the part I find difficult to explain. Pions are the mediating particles of the strong nuclear interaction. The intensity of the interaction depends on the mass of the pions and that mass can, under certain specialized conditions, be altered. The Lunar physicists have developed an instrument they call the Pionizer, which can be made to do just such a thing. Once the pion’s mass is decreased, or increased for that matter, it is, effectively, part of another Universe; it becomes a gateway, a crossing point. If it is decreased sufficiently, it can be made part of a cosmeg-Universe and that’s what we want.”

Gottstein said, “And you can suck in matter from the— the—cosmeg-Universe?”

“That part is easy. Once the gateway forms, the influx is spontaneous. The matter enters with its own laws and is stable when it arrives. Gradually the laws of our own Universe soak in, the strong interaction grows stronger, and the matter fuses and begins to give off enormous energy.”

“But if it is super-dense, why doesn’t it just expand in a puff of smoke?”

“That, too, would yield energy, but that depends on the electromagnetic field and in this particular case the strong interaction takes precedence, because we control the electromagnetic field. It would take quite a time to explain that.”

“Well, then, the globe of light that I saw on the surface was cosmeg material fusing?”

“Yes, Commissioner.”

“And that energy can be harnessed for useful purposes?”

“Certainly. And in any quantity. What you saw was the arrival in our Universe of micromicrogram masses of cosmeg. There’s nothing, in theory, to prevent our bringing it over in ton-lots.”

“Well, then, this can be used to replace the Electron Pump.”

Denison shook his head. “No. The use of cosmeg energy also alters the properties of the Universes in question. The strong interaction gradually grows more intense in the cosmeg-Universe and less intense in ours as the laws of nature cross over. That means that the cosmeg slowly undergoes fusion at a greater rate and gradually warms up. Eventually—”

“Eventually,” sad Gottstein, crossing his arms across his chest and narrowing his eyes, thoughtfully, “it explodes in a big bang.”

“That’s my feeling.”

“Do you suppose that’s what happened to our own Universe ten billion years ago?”

“Perhaps. Cosmogonists have wondered why the original cosmic egg exploded at some one point in time and not at another. One solution was to imagine an oscillating Universe in which the cosmic egg was formed and then at once exploded. The oscillating Universe has been eliminated as a possibility and the conclusion is that the cosmic egg had to exist for some long period of time and then went through a crisis of instability which arose for some unknown reason.”

“But which may have been the result of the tapping of its energy across the Universes.”

“Possibly, but not necessarily by some intelligence. Perhaps there are occasional spontaneous leaks.”

“And when the big bang takes place,” said Gottstein, “can we still extract energy from the cosmeg-Universe?”

“I’m not sure, but surely that is not an immediate worry. The leakage of our strong-interaction field into the cosmeg-Universe must very likely continue for millions of years before pushing it past the critical point. And there must be other cosmeg-Universes; an infinite number, perhaps.

“What about the change in our own Universe?”

“The strong interaction weakens. Slowly, very slowly, our Sun cools off.”

“Can we use cosmeg energy to make up for that?”

“That would not be necessary, Commissioner,” said Denison, earnestly. “While the strong interaction here in our Universe weakens as a result of the cosmeg pump, it strengthens through the action of the ordinary Electron Pump. If we adjust the energy productions of the two then, though the laws of nature change in the cosmeg-Universe and in the para-Universe, they do not change in ours. We are a highway but not the terminus in either direction.