© 1975-1979, 2008 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Xenology: An Introduction to the Scientific Study of Extraterrestrial Life, Intelligence, and Civilization, First Edition, Xenology Research Institute, Sacramento, CA, 1979; http://www.xenology.info/Xeno.htm

17.4.5  Statistical Transport

The mysterious, often apparently "magical" results of modern quantum physics have enticed many writers to try their hand at devising propulsion systems based on the principles of quantum mechanics and statistical thermodynamics. Most of these fall reliably into two general categories: Bootstrap Drives and Heisenberg Drives.

To visualize a Bootstrap Drive, consider a cylindrical vessel filled with ordinary gas. Although each of the molecules is rushing madly about at speeds in the kilometer/second range, the net effect of trillions of particles darting in random directions is a wash-out. The molecule motions are averaged out over the walls of the container, yielding a net system velocity of zero.

About half a century ago, the late John W. Campbell, Jr. suggested that it might be possible to devise an external field that would induce the molecules subject to its influence to assume the highly improbable state of collective upward motion.¹¹¹⁰ Much of scientific experimentation involves the judicious rearrangement of probabilities to achieve desired results, so this idea is certainly not impossible. The result would be a reactionless Bootstrap Drive that could be used to propel spaceships to other worlds.

It is fairly clear that the technology to achieve a bootstrap effect will not be trivial. The magnitude of the difficulty may be made plain with a fairly simple example. Imagine a pan containing a liter of water, placed on a stove that can bring it to a full boil in 15 minutes. Our experiment consists simply of heating the liter of water to the boiling point over and over again. According to the laws of statistical thermodynamics, there is a very small but nonzero probability that during one experimental cycle the molecules will spontaneously arrange themselves in crystalline form -- that is, freeze instead of boil. But calculations show that this event is so improbable that it is expected to occur only once in every 10^{10,000,000,000,000,000,000} years, assuming 15 minute cycles. Clearly, to enhance such miniscule probabilities will not be easy.

But if it could be done, the Bootstrap Drive would permit a container of gases to move on its own without the ejection of any reaction mass. The ship would rise up, so to speak, by tugging on its own bootstraps. In normal operation, the Bootstrap Drive would give up thermal energy and become very cold. To maintain the propulsive force, it should be necessary to supply additional energy to the system in the form of heat.

In the 1940s Campbell also came up with a number of starship propulsion system designs operating on Heisenberg’s Uncertainty Principle in quantum mechanical theory. Arthur C. Clarke describes the functioning of the Heisenberg Drive:

In the Uncertainty Theory, a particle cannot be said to have a fixed position in space but has a very small, though finite, probability of being anywhere in the universe. All you had to do, therefore, to get an instantaneous mode of transport was to manipulate the Heisenberg equations until you were more likely to be somewhere else than where you started, and -- presto!¹¹¹⁰

In essence, starships using the Heisenberg Drive "move" by going from maximum probability of existence at one position in the universe, through universality, to maximum probability of existence at another position elsewhere.²⁶⁴²

Last updated on 6 December 2008