PARTICLE PHYSICS ADVANCED PROPULSION ONCEPTS A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site Casimir effect A small attractive force that acts between two close parallel uncharged conducting plates. Its existence was first predicted by the Dutch physicist Hendrick Casimir in 19481 and confirmed experimentally by Steven Lamoreaux, now of Los Alamos National Laboratory, in 19962, 3. The Casimir effect is one of several phenomena that provide convincing evidence for the reality of the quantum vacuum – the equivalent in quantum mechanics of what, in classical physics, would be described as empty space. It has been linked to the possibility of faster-than-light travel. According to modern physics, a vacuum is full of fluctuating electromagnetic waves of all possible wavelengths which imbue it with a vast amount of energy, normally invisible to us. Casimir realized that between two plates, only those unseen electromagnetic waves whose wavelengths fit a whole number of times into the gap should be counted when calculating the vacuum energy. As the gap between the plates is narrowed, fewer waves can contribute to the vacuum energy and so the energy density between the plates falls below the energy density of the surrounding space. The result is a tiny force trying to pull the plates together – a force that has been measured and thus provides proof of the existence of the quantum vacuum. Casimir effect and propulsion This may be relevant to space travel because the region inside a Casimir cavity has negative energy density. Zero energy density, by definition, is the energy density of normal " empty space." Since the energy density between the conductors of a Casimir cavity is less than normal, it must be negative. Regions of negative energy density are thought to be essential to a number of hypothetical faster-than-light propulsion schemes, including stable wormholes and the Alcubierre warp drive. There is another interesting possibility for breaking the light-barrier by an extension of the Casimir effect. Light in normal empty space is " slowed" by interactions with the unseen waves or particles with which the quantum vacuum seethes. But within the energy-depleted region of a Casimir cavity, light should travel slightly faster because there are fewer obstacles. A few years ago, K. Scharnhorst of the Alexander von Humboldt University in Berlin published calculations4 showing that, under the right conditions, light can be induced to break the usual light-speed barrier. Under normal laboratory conditions this increase in speed is incredibly small, but future technology may afford ways of producing a much greater Casimir effect in which light can travel much faster. If so, it might be possible to surround a space vehicle with a " bubble" of highly energy-depleted vacuum, in which the spacecraft could travel at FTL velocities, carrying the bubble along with it. References Casimir, H. G. B. "On the attraction between two perfectly conducting plates." Proc. Con. Ned. Akad. van Wetensch B51 (7): 793-796 (1948). Lamoreaux, S. K. "Demonstration of the Casimir force in the 0.6 to 6 mm range." Physical review Letters 78 (1): 5-8 (1997). Schwinger, J. "Casimir light: The source." Proceedings of the National Academy of Science, 90: 2105-6 (1993). Scharnhorst, K. Physics Letters B236: 354 (1990). Related categories    • PARTICLE PHYSICS    • ADVANCED PROPULSION CONCEPTS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP