Excerpt from Starfarers by Poul Anderson, plus links to reviews, author biography & more

Fleury had regained her smile. 'A word nearly as knotty as the problem."

"It takes very powerful force fields," Olivares said. 'Again we meet the question of energy. Of course, the requirement is minuscule compared to what's necessary for the speed."

'And nobody could build a nuclear power plant to supply that."

"No. If you did, you'd find you had built a star."

"Then where does the energy come from?"

"The original suggestion was that it comes from the vacuum."

"Could you explain that? It sounds like, well, Alice's Cheshire cat."

Olivares shrugged. 'A good deal of quantum mechanics does. Let me try. Space is not a passive framework for events to happen in. It is a sea of virtual particles. They constantly go in and out of existence according to the uncertainty principle. The energy density implied is tremendous."

"But we don't know how to put the vacuum to work, do we?"

"Only very slightly, as in the Casimir effect. You see, the more energy you 'borrow' from the vacuum, the shorter the time before it must be returned.' Both these quantities, energy and time, are far too small to power a spacecraft."

"But now you, Dr. Olivares, have shown how it can be done," Fleury said softly

He shook his head. "Not by myself I simply pursued some speculations that go back to the last century. And then the new information started to come in from the new instruments."

Fleury gestured. The galaxy gave way to the observatory on Lunar Farside. After a few seconds the scene swept across millions of kilometers to the devices in their huge orbits. Representations of laser beams quivered between them and back toward the Moon, bearing data. An antenna pointed at a constellation. Briefly, the outlines of a centaur stood limned amidst those stars. It vanished, and a telescopic view expanded. it zoomed past a globular cluster of suns, on toward the one called Zeta, and on and on beyond. Tiny fireballs twinkled into existence, crawled across the deep, and died back down into the darkness while fresh ones appeared. "The bow waves of the argosies," Fleury intoned.

The animations ended. The galaxy came back.

"Details we could not detect before, such as certain faint spectral lines, are now lending confirmation to my cosmodynamic model," Olivares said. 'And that model, in turn, suggests the energy source for such spacecraft. That's all," he ended diffidently

"I'd say that's plenty, sir," the journalist responded. "Could you tell us something about your ideas?"

"It's rather technical, I fear."

"Let's be brave. Please say whatever you can without equations."

Olivares leaned back and drew breath. "Well, cosmologists have agreed for a long time that the universe originated as a quantum fluctuation in the seething sea of the vacuum, a random concentration of energy so great that it expanded explosively. Out of this condensed the first particles, and from them evolved atoms, stars, planets, and living creatures."

Excitement throbbed beneath the academic phrases. 'At first the cosmologists took for granted that the beginning involved a fall to the ground state, somewhat like the transition of an electron in a high orbit to the lowest orbit it can occupy But what if this is not the case? What if the fall is only partway? Then a reservoir of potential energy remains. For an electron, it's a photon's worth, For a universe, it is vast beyond comprehension,

"I've shown that, if the cosmos is in fact in such a metastable condition, we can account for what the astronomers have observed, as well as several other things that were puzzling us. it's possible to tap energy from the unexpended substrate­energy more than sufficient, for lengths of time counted not in Planck units but in minutes, even hours."

Excerpted from Starfarers by Poul Anderson. Reproduced with the permission of the publisher. Published by Tor Books. No part of this book can be reproduced without permission from the publisher. Copyright (c) 1998 Poul Anderson,