Cities in Flight

“Quite. Of course, we’ll continue to operate it for a while. You can’t stop a process of that size on a dime. Besides, one of the reasons why we built the Bridge was because the USSR expected us to; the game said that we should launch another Manhattan District or Project Lincoln at this point, and we hated to disappoint them. One thing we are not going to do this time, however, is to tell them the problem that the project was supposed to solve—let alone that it can be solved, and has been.

“So we’ll keep the Bridge going, physically and publicly. That’ll be just as well, too, for people like Dillon who are emotionally tied up in it, above and beyond their conditioning to it. You’re the only person in authority in the whole station who’s already lost enough interest in the Bridge to make it safe for me to tell you that it’s being abandoned.”

“But why?”

“Because,” Wagoner went on quietly, “the Bridge has now given us confirmation of a theory of stupendous importance—so important, in my opinion, that the imminent fall of the West seems like a puny event in comparison. A confirmation, incidentally, which contains in it the seeds of ultimate destruction for the Soviets, whatever they may win for themselves in the next hundred years or so.”

“I suppose,” Helmuth said, puzzled, “that you mean antigravity?”

For the first time, it was Wagoner’s turn to be taken aback. “Man,” he said at last, “do you know everything I want to tell you? I hope not, or my conclusions will be mighty unwelcome to both of us. Do you also know what an anti-agathic is?”

“No,” Helmuth said. “I don’t even recognize the root of the word.”

“Well, that’s a relief. But surely Charity didn’t tell you we had antigravity. I strictly enjoined him not to mention it.”

“No. The subject’s been on my mind,” Helmuth said. “But I certainly don’t see why it should be so world-shaking, any more than I see how the Bridge helped to bring it about. I thought it would be developed independently, for the further exploitation of the Bridge. In other words, to put men down there, and short-circuit this remote control operation we have on Jupiter V. And I thought it would step up Bridge operation, not discontinue it.”

“Not at all. Nobody in his right mind would want to put men on Jupiter, and besides, gravity isn’t the main problem down there. Even eight gravities is perfectly tolerable for short periods of time—and anyhow a man in a pressure suit couldn’t get five hundred miles down through that atmosphere before he’d be as buoyed up and weightless as a fish—and even more thoroughly at the mercy of the currents.”

“And you can’t screen out the pressure?”

“We can,” Wagoner said, “but only at ruinous cost. Besides, there’d be no point in trying. The Bridge is finished. It’s given us information in thousands of different categories, much of it very valuable indeed. But the one job that only the Bridge could do was that of confirming, or throwing out, the Blackett-Dirac equations.”

“Which are—?”

“They show a relationship between magnetism and the spinning of a massive body—that much is the Dirac part of it. The Blackett Equation seemed to show that the same formula also applied to gravity; it says G equals (2CP/BU ² ), where C is the velocity of light, Pis magnetic moment, and U is angular momentum. B is an uncertainty correction, a constant which amounts to 0.25.

“If the figures we collected on the magnetic field strength of Jupiter forced us to retire the equations, then none of the rest of the information we’ve gotten from the Bridge would have been worth the money we spent to get it. On the other hand, Jupiter was the only body in the solar system available to us which was big enough in all relevant respects to make it possible for us to test those equations at all. They involve quantities of infinitesimal orders of magnitudes.

“And the figures showed that Dirac was right. They also show that Blackett was right. Both magnetism and gravity are phenomena of rotation.

“I won’t bother to trace the succeeding steps, because I think you can work them out for yourself. It’s enough to say that there’s a drive-generator on board this ship which is the complete and final justification of all the hell you people on the Bridge have been put through. The gadget has a long technical name—The Dillon-Wagoner gravitron polarity generator, a name which I loathe for obvious reasons—but the technies who tend it have already nicknamed it the spin-dizzy, because of what it does to the magnetic moment of any atom —any atom—within its field.