An interesting effect posited by
James F. Woodward, professor of
History and
Physics at the
State University of California Fullerton. It is based on
Mach's Principle. According to
Woodward, changing the
mass of an object is possible, at least
transiently, by rapidly changing its
energy density.
Here is a more complete description, from the Quantum Cavorite:
Mach's Principle explains inertia -- the tendency of an object to resist acceleration -- by the sum of the gravitational attractions of all objects in the
universe. Woodward, an expert on Mach's Principle, found a "loop hole" (really, a transient term that most neglect) which predicts that a
time-varying energy density results in a sizeable mass fluctuation, and has demonstrated this in more than one well documented experiments.
He predicts that this is only possible if Mach's Principle is valid, because a certain constant in his equations approaches c2, which cancels out the c2
in Einstein's E = Mc2; if Mach's Principle is invalid, then rapidly changing energy densities (of a magnitude possible in a modern lab) would not
result in large mass fluctuations because the c2 term would be very large.
His experiments used a small array of capacitors whose energy density was varied by an applied 11 kHz signal. The beauty of his experiment was
the following insight -- if you vibrate these capacitors up and down using a piezoelectric crystal, at just the right frequency so that they are going
up when their mass is the least and going down when their mass is the most, then a small, constant, mass change is possible. The largest mass
change he measured was 4.4 milligrams.