TWEAKING FLUX CAPACITORS James F. Woodward Departments of History and Physics, California State University, Fullerton, CA 92834 714-278-3596; jwoodward@fullerton.edu Abstract. Mass fluctuations that arise from Mach effects when objects that can store internal energy are accelerated and their application to the production of propellantless thrusts are discussed. A follow-on experiment to that reported at STAIF 2004 is described. An effect of the sort expected continues to be observed. And it displays scaling behavior distinctive to Mach effects. MACH’S PRINCIPLE AND THE ORIGIN OF INERTIA Named by Einstein about the time he invented GRT, Mach’s principle is the assertion that the manifestations of inertia cannot be entirely innate and inherent, or simply imbued in material objects by virtue of their existence in absolute space. Rather, the manifestations of inertia in matter must arise from the presence in the universe of the rest of its material contents. This means that ma in Newton’s second law must arise as a consequence of accelerations with respect to the bulk of the matter in the universe as a consequence of the action of that matter on the accelerating object. Mach’s principle has a tortuous history, chiefly because both Newton and Mach couched much of their discussion of absolute space and inertia in terms of rotational motion (Newton’s famous bucket and its contents). The result has been some deeply confused and misguided arguments relating to the issue of the origin of inertia. We ignore rotation, for all of that follows as long as the relativistic version of Newton’s three laws of mechanics obtain. In the context of the three laws, Mach’s principle can be stated very simply: The inertial reaction forces that agents acting on objects experience when they exert accelerating forces on those objects are the consequence of the gravitational action of the rest of the matter in the universe on the objects. Matter here is to be understood as any substance that exerts a gravitational action on other matter, as in GRT, not simply as electrons, neutrons, and protons. It turns out that this is true when the inertial masses of things are just equal to their total gravitational potential energies divided by the square of the speed of light. Is Mach’s principle consistent with GRT? That is a matter of continuing contention. Derek Raine (Raine, 1975) showed that inertial reaction forces are caused by the gravitational action of cosmic matter if that matter is distributed isotropically. That is, the addition of the “boundary condition” of isotropically distributed matter at cosmological scale to GRT allows one to incorporate Mach’s principle in GRT. But his analysis did not take account of the energy supposed to be associated with gravity waves; so it is not considered compelling by some. Nonetheless, the equivalence of inertial and passive gravitational mass (the “weak” Equivalence Principle), and the implausibility of the proposition that inertia is a completely innate property of matter, suggests that Mach’s principle is correct. If so, does this open up possibilities for the solution of the propulsion challenges? That is, can means be found to accelerate objects without the expulsion of material propellants? And more radically, can “exotic” matter be induced in sufficient quantities to make traversable wormholes? If the results of the continuing investigation reported here are valid, it seems that the answers to these propulsion questions may be “yes”. MACH EFFECTS Treating inertia as a gravitational phenomenon makes the sources of local gravitational phenomena – now including 1345 CP746, Space Technology and Applications International Forum—STAIF 2005, edited by M. S. El-Genk © 2005 American Institute of Physics 0-7354-0230-2/05/$22.50