James F. Woodward

James F. Woodward (1941 – August 9, 2025

Mach effects Woodward claimed that his hypothesis predicts physical forces that he calls Mach effects but are also referred to as the Woodward effect. He said that his hypothesis was based on Mach's principle that posits inertia, the resistance of mass to acceleration, is a result of the mutual gravitational attraction of all matter in the universe. Thus, if the mass of a given object can be varied while being oscillated in a linear or orbital path, such that the mass is high while the mass is moving in one direction and low while moving back, then the net effect should be acceleration in one direction as the inertial drag of the universe upon the object varies as its mass varies. If a spacecraft engine could be designed to exploit it then acceleration could be produced without using rocket propellants. The effect is controversial because within mainstream physics the underlying model proposed for it appears to be faulty, resulting in violations of energy conservation as well as momentum conservation. Woodward and his associates have claimed since the 1990s to have successfully measured forces at levels great enough for practical use and also claim to be working on the development of a practical prototype thruster. No practical working devices have been publicly demonstrated, and other experiments have failed to corroborate these claims.

James F. Woodward's Mach-effect propulsion program grew out of his long interest in using Mach's principle to pursue propellantless propulsion. By 1995, according to a later Wired profile, Woodward's ideas about Mach effects had coalesced into a full theory, and he turned to building a thruster based on stacks of piezoelectric disks that he believed could exploit tiny transient mass fluctuations. especially wormholes. In 2012, he published a book on the application of the physical effects predicted by his hypothesis to space travel.

Personal life Woodward died on August 9, 2025 at the age of 84.