antigravity n.

A disk of platinum coated with my new preparation, in which, I may say, radium plays some part, has a propelling power of immense force. I say ‘propelling power,’ but between you and me, I don’t think that conventional term properly applies to the strange force. For want of better name I am temporarily referring to it by the ridiculous and wholly inadequate name of ‘Anti-Gravity.’

Anti-gravity had come almost simultaneously, and completely opened the system to colonization, but by that time the Interplanetary Union got nasty, and wouldn't permit any further emigration from earth.

I think that Cambell [sic] was the first to point out in a story that to render a body completely weightless by an antigravity machine would require the consumption of the amount of energy necessary to lift a weightless body to any height with the application of very little power, remove the antigravity, and let the body fall under its weight, thus generating energy out of nothing, which is not allowed.

‘They have antigravity! Isn’t that it?’ ‘Yes…. Of course, it couldn’t be a complete gravity screen by any means. But it seems to be a good long step toward it.’

Nita nodded, fluttered her tapered fingers in my direction, and whisked her svelte, body-suited figure out of the picture. Where she had been I saw something I recognized behind Bob’s shoulder: one of those stretched guts from the Wailies of Tchan that’s supposed to show images of the future if you expose it to anti-gravity.

What of course I would like to be writing is the story of the Red and White Dwarves and their Remembering Mirror, their space rocket (powered by anti-gravity), their attendant entities Hadron, Gluon, Pion, Lepton, and Muon, and the Charmed Quarks and the Coloured Quarks. But we can’t all be physicists.

Adults just assumed that there was some trick behind the apparently unsupported body of the machine, but children wanted to know how it worked. One or two scientists and engineers had looked startled, too, but she guessed a stereotype of unworldiness [sic] meant nobody believed them that there must be something odd going on. Anti gravity was what was going on, and the drone in this society was like a flashlight in the stone age, but—to her surprise—it was almost disappointingly easy just to brazen it out.

‘How much carbon is locked up in this? Carlyle asked. ‘Many millions of tons,’ said the familiar. ‘An entire coal measure, I would say, save that coal measures seem unlikely here.’ ‘Or an entire carbonaceous chondrite? Could they have done that?’ ‘If so it would be a quite profligate use of anti-gravity.’ Shlaim sounded skeptical. ‘Or they could have lowered it from a skyhook, I suppose, but it would seem pointless...’ Carlyle laughed. ‘Since when has that ever ruled out anything they did?’

‘We do what must be done. And even then only when truly disruptive innovation occurs and containment risks are high.’ ‘What “containment risks”?’ ‘Some technologies are too dangerous to be allowed to spread on their own. Left to chance, technologies like fusion and antigravity would sweep away existing social systems. They would change every society they touched.’