Posted on 02/02/2004 6:46:02 AM PST by PatrickHenry
Motion can be conjured out of thin air, according to a physicist in Israel.
Alexander Feigel of the Weizmann Institute of Science in Rehovot says that objects can achieve speeds of several centimetres an hour by getting a push from the empty space of a vacuum1.
No one has yet measured anything being set in motion by emptiness. But Feigel thinks it should theoretically be possible to make use of the effect to shunt tiny amounts of liquids around on a lab chip, for example. Such small-scale experiments could be useful for chemists interested in testing thousands of different drugs at the same time, or for forensic scientists who need to do analyses on tiny amounts of material.
The whole idea of getting movement from nothing sounds like a gift to advocates of perpetual-motion machines. But there's nothing in Feigel's theory that violates the fundamental laws of physics, so this doesn’t provide a way to cheat the Universe and get free energy.
Instead, Feigel draws on the well-established notion that empty space does contain a little bit of energy. This ‘vacuum energy’ is a consequence of the uncertainty principle — one of the cornerstones of quantum mechanics.
Because of the uncertainty principle, subatomic particles or photons can appear spontaneously in empty space — provided that they promptly vanish again. This constant production and destruction of 'virtual particles' in a vacuum imbues the vacuum with a small amount of energy.
Moving in a vacuum
Feigel considered the effects of virtual photons on the momentum — a property defined as mass multiplied by velocity — of objects placed in a vacuum, and came to a surprising conclusion.
He started with the fact that electrical and magnetic forces between objects are mediated by photons that flit between them. So an object placed in strong electric and magnetic fields can be considered to be immersed in a sea of these transitory, virtual photons.
Feigel then showed that the momentum of the virtual photons that pop up inside a vacuum can depend upon the direction in which they are travelling. He concludes that if the electric field points up and the magnetic field points north, for example, then east-heading photons will have a different momentum from west-heading photons.
So the vacuum acquires a net momentum in one direction — it’s as though the empty space is ‘moving’ in that direction, even though it is empty.
It is a general principle of physics that momentum is ‘conserved’ — if something moves one way, another thing must move the other way, as a gun recoils when it shoots a bullet. So when the vacuum acquires some momentum from these virtual photons, the object placed within it itself starts to move in the opposite direction.
Feigel estimates that in an electric field of 100,000 volts per metre and a magnetic field of 17 tesla — both big values, but attainable with current technology — an object as dense as water would move at around 18 centimetres per hour.
Is this the basis for the infinite improbability drive used in some starships?
Quantum Vacuum Contribution to the Momentum of Dielectric Media
A. Feigel
Department of Complex Systems, Weizmann Institute of Science, Rehovot 76100, Israel
(Received 3 February 2003; published 16 January 2004)
Momentum transfer between matter and electromagnetic field is analyzed. The related equations of motion and conservation laws are derived using relativistic formalism. Their correspondence to various, at first sight self-contradicting, experimental data (the so-called Abraham-Minkowski controversy) is demonstrated. A new, Casimir-like, quantum phenomenon is predicted: contribution of vacuum fluctuations to the motion of dielectric liquids in crossed electric and magnetic fields. Velocities of about 50 nm/s can be expected due to the contribution of high frequency vacuum modes. The proposed phenomenon could be used in the future as an investigating tool for zero fluctuations. Other possible applications lie in fields of microfluidics or precise positioning of micro-objects, e.g., cold atoms or molecules. ©2004 The American Physical Society
URL: http://link.aps.org/abstract/PRL/v92/e020404 doi:10.1103/PhysRevLett.92.020404 PACS: 03.50.De, 42.50.Nn, 42.50.Vk
Nothing. This is the reason that Browninan motion sets a lower limit on measurement. When a probe small enought to detect the particles motion is used, the probe itself is subject to Brownian motion. The existence of molecules (or atoms or monads, etc.) is sufficient to explain the effect. Actually, Brownian motion can be taken as proof of the existence of atoms. (This is not the same as Heisenberg's uncertainty which is a quantum effect.)
Well, heck. Water is a polar molecule; even a modest voltage is enough to move it around. Rub a latex balloon on your hair and hold it close to a running faucet, and you'll see what I mean.
As for non-polar materials, put them in a strong enough electric field and you will induce an electric dipole moment.
The effect this guy claims may or may not be real--I haven't really looked at it--but I don't see it having any practical applications that can't be obtained with classical physics.
Me neither---but it is interesting as a directly observable result of quantum effects.
1. Is the energy for the motion just drawn from the externally applied field?
2. Isn't the probablity of a spontaneously generated particle uniform over space and don't the generated particles have zero momentum with a uniform distribution?
3. Wouldn't #2 imply just drift similar to Brownian motion? (Albeit quantumly generated.)
4. Wouldn't the field necessary to orient #3 lead back to question #1.
Now I'll look up the article. Perhaps the proposal is to use the virtual particles to mediate the fields as pushers.
Yes, "there's nothing in Feigel's theory that violates the fundamental laws of physics, so this doesn’t provide a way to cheat the Universe and get free energy."
50 nm/s = 50 nanometers/second = 50 * 10^-9 meters/sec =
5.0*10^-8 meters/sec * 3.6*10^3 sec/hour =
1.8*10^-4 meters/hour = 1.8*10^-2 cm/hour
Isn't this story
just another version of
zero-point fluxes?
"... From this line of reasoning, quantum physics predicts that all of space must be filled with electromagnetic zero-point fluctuations (also called the zero-point field) creating a universal sea of zero-point energy. The density of this energy depends critically on where in frequency the zero-point fluctuations cease. Since space itself is thought to break up into a kind of quantum foam at a tiny distance scale called the Planck scale (10-33 cm), it is argued that the zero point fluctuations must cease at a corresponding Planck frequency (1043 Hz). If that is the case, the zero-point energy density would be 110 orders of magnitude greater than the radiant energy at the center of the Sun. ..."
[An Introduction to Zero-Point Energy, ]
Some Empties in Washington move about in a vacuum.
It's about a hitherto unpredicted consequence of zero-point fluxes.
Feigel then showed that the momentum of the virtual photons that pop up inside a vacuum can depend upon the direction in which they are travelling. He concludes that if the electric field points up and the magnetic field points north, for example, then east-heading photons will have a different momentum from west-heading photons.I thought that here's a novel way to do something like an updated version of the Michelson-Morely expermiment. Does the momentum of the vacuum have a direction? An absolute direction?So the vacuum acquires a net momentum in one direction — it’s as though the empty space is ‘moving’ in that direction, even though it is empty.
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