"John Smith" bravely wrote to "All" (12 May 05 18:16:40)
--- on the heady topic of " Reflector Vs Director"

JS Reply-To: "John Smith"
JS Xref: aeinews rec.radio.amateur.antenna:30219

JS Asimov:

JS Then:

JS If I were shrunk to the size were an atom is the size of an orange
JS and, I am holding it in my hand--and I look over at the next closest
JS atom, in the block of lead I am standing in, and it appears to be
JS about a football field length away... and if we agree on the
JS preceeding... I have a LOT of this "free energy" and "virtual photons"
JS in my body--correct?
JS Indeed, my antenna has a LOT of it, in its' metal, does it not? And,
JS it is swimming in it, is it not? And, if so, kinda strange no formula
JS takes that into account, right?


Yes there is but the average net result of this energy is always zero.
However, it can be detected as the Casimir Effect, Lamb Shift, and Van
de Waals Forces which arise from the random motions of electrons. Some
people have even described this effect as responsible for Dark Energy
or Zero Point Energy, Fermi Sea, Quantum Ocean, or whatever
descriptive term you like best. Some have speculated it is also
responsible for the observed accelerating expansion of the universe.

Some explanations--

Lamb Shift:

" The effect of virtual particles can be measured, and in fact won a
nobel prize for the physicist who did. the lamb shift is the shift
in the spectrum of an electron around a nucleus caused by virtual
particles swarming around it.
"

Casimir Effect:

"
The following comes from the Usenet Physics FAQ
(http://math.ucr.edu/home/baez/physics/faq.html) and includes some
references:

Original by Philip Gibbs 24-January-1997

What is the Casimir Effect?

The Casimir effect is a small attractive force which acts between
two close parallel uncharged conducting plates. It is due to quantum
vacuum fluctuations of the electromagnetic field.

The effect was predicted by the Dutch physicist Hendrick Casimir in
1948. According to the quantum theory, the vacuum contains virtual
particles which are in a continuous state of fluctuation (see
physics FAQ article on virtual particles). Casimir realized that
between two plates, only those virtual photons whose wavelengths fit
a whole number of times into the gap should be counted when
calculating the vacuum energy. The energy density decreases as the
plates are moved closer which implies there is a small force drawing
them together.

The attractive Casimir force between two plates of area A separated
by a distance a can be calculated to be,

pi2 h-bar c
F = ----------- A
240 a4

where h-bar is Planck's constant over two pi and c is the speed of
light.

The tiny force was measured in 1996 by Steven Lamoreaux. His results
were in agreement with the theory to within the experimental
uncertainty of 5%.

Particles other than the photon also contribute a small effect but
only the photon force is measurable. All Bosons such as photons
produce an attractive Casimir force while Fermions make a repulsive
contribution. If electromagnetism was supersymmetric there would be
fermionic photinos whose contribution would exactly cancel that of
the photons and there would be no Casimir effect. The fact that the
Casimir effect exists shows that if supersymmetry exists in nature
it must be a broken symmetry.

According to the theory the total zero point energy in the vacuum is
infinite when summed over all the possible photon modes. The Casimir
effect comes from a difference of energies in which the infinities
cancel. The energy of the vacuum is a puzzle in theories of quantum
gravity since it should act gravitationally and produce a large
cosmological constant which would cause space-time to curl up. The
solution to the inconsistency is expected to be found in a theory of
quantum gravity.

References
H.B.G. Casimir, Proc. Kon. Ned. Akad. Wetensch. B51, 793 (1948)
S. Lamoreaux, Phys Rev Lett, 78, p5 (1996)

"


A*s*i*m*o*v

.... Be nice to your kids. They'll choose your nursing home.