Foundations of Physics, Vol. 34, No. 10, October 2004 (© 2004) Flux Capacitors and the Origin of Inertia James F. Woodward 1 Received April 19, 2004; revised July 26, 2004 The explanation of inertia based on “Mach’s principle” is briefly revisited and an experiment whereby the gravitational origin of inertia can be tested is described. The test consists of detecting a small stationary force with a sensitive force sensor. The force is presumably induced when a periodic transient Mach effect mass fluctuation is driven in high voltage, high energy density capacitors that are subjected to 50 kHz, 1.3 kV amplitude voltage signal, and threaded by an alternating magnetic flux of the same frequency. An effect of the sort pre- dicted is shown to be present in the device tested. It has the expected mag- nitude and depends on the relative phase of the Mach effect mass fluctuation and the alternating magnetic flux as expected. The observed effect also displays scaling behaviors that are unique to Mach effects. Other tests for spurious sig- nals suggest that the observed effect is real. KEY WORDS: Mach’s principle; origin of inertia; flux capacitors; mass fluc- tuations. 1. INTRODUCTION Over a century has passed since Ernst Mach conjectured that the cause of inertia should somehow be causally related to the presence of the vast bulk of the matter (his “fixed stars”) in the universe. Einstein translated this conjecture into “Mach’s principle” (his words) and attempted to incor- porate a version of it into general relativity theory (GRT) by introduc- ing the “cosmological constant” term into his field equations for gravity. (1) Einstein ultimately abandoned his attempts to incorporate Mach’s princi- ple into GRT. But in the early 1950s Dennis Sciama revived interest in the “origin of inertia.” (2) Mach’s principle can be stated in very many ways. (Bondi and Samuel in a recent article list twelve versions, and their list is 1 Departments of History and Physics, California State University, Fullerton, California; e-mail: jwoodward@fullerton.edu 1475 0015-9018/04/1000-1475/0 © 2004 Springer Science+Business Media, Inc.