Historical research guide · 1021 · 2013
Making Starships and Stargates: The Science of Interstellar Transport and Absurdly Benign Wormholes
James F. Woodward
In one minute
James Woodward is an adjunct professor of physics and an emeritus professor of the history of science at Cal State Fullerton, and this 2013 Springer book is where he gathers three decades of his own work into a single argument. It begins with Mach’s principle: that a body’s inertia — its resistance to being pushed — is not something the body owns, but the sum of its gravitational relationship with all the other matter in the universe. If that is right, Woodward argues, then a body whose internal energy is changing while it is being accelerated will have its mass fluctuate, briefly and slightly. Those fluctuations are his Mach effects, and they are the whole point: cycle the energy in step with the acceleration and you get a steady push with nothing thrown out of the back. The book runs in three parts — the relativity needed to follow the prediction, the bench experiments testing whether the effect is real and usable, and, most speculative, what physics would be required to build a wormhole a person could walk through.
Connection
Chapter 8 is about getting thrust by changing what a craft weighs rather than by ejecting mass, and this is the fullest single statement of the one such proposal that has been built, run, and retested by other laboratories on another continent. Chapter 4 gets the far end of the same argument: Woodward’s route to a traversable wormhole runs through the same mass-fluctuation term, driven hard enough to swing negative.
From the source
The book’s foundation is that inertia is gravitational in origin: the reaction force you feel when you push an object is the object’s interaction with all the rest of the matter in the universe, which is Mach’s principle taken as physics rather than as philosophy. Part I sets out the relativity needed to state that prediction properly before using it.Part I, chapters 1 and 2, The Principle of Relativity and the Origin of Inertia, pages 3 to 27, and Mach’s Principle, pages 29 to 64
From that foundation comes the prediction the whole programme rests on: an object whose internal energy density is changing while it is being accelerated undergoes a transient fluctuation in its mass. These are the Mach effects, and Woodward first published the derivation and a bench test of it in 1990.Part I, chapter 3, Mach Effects, pages 65 to 86; the underlying paper is Woodward, Foundations of Physics Letters 3, 497 (1990)
The engineering consequence is a thruster with no propellant. If the mass fluctuation is made to swing in step with the motion of the mass — heavy on the push, light on the return — the cycle leaves a net force behind, so the craft accelerates without a reservoir of fuel to blow out of a tailpipe. Springer’s own framing of the book puts that goal first: accelerating a spaceship without having to carry the propellant.Part I, chapter 3, Mach Effects, pages 65 to 86; publisher’s description of the book
Part II is the experimental half, and it is written as an open question rather than a result: do the predicted effects exist, and can they be applied to propulsion? Two long chapters, ninety pages together, set out the apparatus, the measurements and the ways a small force can fool you.Part II, chapters 4 and 5, Getting in Touch with Reality, pages 89 to 132, and In Reality’s Grip, pages 133 to 179
Part III asks what a wormhole would actually cost. A traversable one needs mass-energy of the wrong sign holding its throat open, so Woodward devotes a chapter to where exotic matter might be found and another to the classical point-charge electron of Arnowitt, Deser and Misner — the standard model in which the observed mass of an electron is what is left after a negative bare mass is combined with a divergent electromagnetic self-energy. His case is that negative mass-energy is already an ordinary ingredient of physics, not an exotic import.Part III, chapters 6 to 8, Advanced Propulsion in the Era of Wormhole Physics, pages 183 to 206; Where Do We Find Exotic Matter?, pages 207 to 223; Making the ADM Electron Plausible, pages 225 to 234
The book ends by designing the thing in its title. Making Stargates asks how one would actually build an absurdly benign wormhole — Morris and Thorne’s name for a throat whose exotic material is confined to a thin shell, so that a traveller passing through feels almost nothing — and The Road Ahead names the work that would have to come first. What to watch is the experimental question Part II leaves open: a Mach-effect thrust that survives being measured on someone else’s balance, at the predicted scaling, is what would move the whole programme forward.Part III, chapters 9 and 10, Making Stargates, pages 235 to 257, and The Road Ahead, pages 259 to 267
The way in
https://doi.org/10.1007/978-1-4614-5623-0How to cite it
James F. Woodward (2013) Making Starships and Stargates: The Science of Interstellar Transport and Absurdly Benign Wormholes doi:10.1007/978-1-4614-5623-0