 According to quantum field theory, as those virtual particles have an energy more than twice the bare mass of the electron, mandatory for pair production in renormalization, the nonelectromagnetic bare mass of the "unclothed" electron has to be "negative".Using the ADM formalism, Woodward proposes that the physical interpretation of the "wormhole term" in his transient mass equation could be a way to expose the negative bare mass of the electron, in order to produce large quantities of exotic matter that could be used in a warp drive to propel a spacecraft or generate traversable wormholes.Current spacecraft achieve a change in velocity by the expulsion of propellant, the extraction of momentum from stellar radiation pressure or the stellar wind or the utilisation of a gravity assist ("slingshot") from a planet or moon.