OK now we are honing in on the fly in Jim's soup. Jim wrote:

"a fictitious force is one that produces the same acceleration irrespective of the mass of the object on which it acts.  It has nothing to do with whether the force is real or not." Footnote 5

Jim's first sentence is correct as far as it goes. It does not go far enough to explain the concept in its fullness. Jim's second sentence is misleading.

First: What is the proper definition of a "real force"?

A real force acting locally in a small region of spacetime is what an accelerometer placed in that region measures.


also see


Special Relativity SR works locally in GR (EEP).

Non-rotating accelerometers on timelike geodesics measure ZERO.

The pattern of timelike geodesics are the INERTIAL PROPERTIES of space. e.g. Lense-Thirring effect dragging of LIFs by rotating source masses


Mach's Principle (MP) would conceivably apply to this pattern of timelike & null geodesic.

The timelike geodesics provide the local GEOMETRODYNAMIC reference field upon which "inertia" according to Newton's 2nd law is measured.

Inertia is the ratio of applied external electromagnetic-weak-strong force to what accelerometers measure.

Real test particles obey Einstein's mass shell constraint

E^2 = (mc^2) + (pc)^2

(poles of the Feynman propagator in the complex energy plane in quantum field theory)

Virtual particles violate the above constraint.

Both real and virtual particles directly bend space time in different ways i.e. both contribute to the Tuv source tensor in

Guv + (8piG/c^4)Tuv = 0

Mach's principle and Einstein's GR have nothing whatsoever to do with the origin of the rest masses m of the elementary particles.

The pattern of rest masses m come from quantum field theory (including Higgs) of the electromagnetic-weak-strong interactions.

The rest masses m are UNDETERMINED PARAMETERS as far as MP & GR are concerned.

m is also called inertial mass = gravity mass (part of the EP).

Therefore, anyone who claims that the actual values of m are determined by GR & MP is most definitely confused and wrong in my opinion.

They confuse the inertial properties of space-time given by GR with the inertia of elementary particles m.

On Dec 26, 2012, at 6:40 PM, JACK SARFATTI <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:

No point wasting more time on this quicksand rut.
I want to move on reading Jim's book.
I think I have made the point clearly with detailed math for two independent situations that I think u & Jim confound.
I argue with equations as much as possible and Z your verbal explanations generally make no sense to me.
What you still don't understand Z is that

Case 1: the observed test particle on geodesic when observed in a non-inertial frame will show apparent fictitious Coriolis, Euler, centrifugal forces and Newtonian gravity forces on that test particle whose accelerometer pointer stays at zero. In contrast the frame accelerometer pointer is off zero. Therefore, in that case, the apparent forces on the geodesic test particle are simply optical illusions.

Case 2: The observed test particle is now pushed off geodesic by a real constraint force. In that case the test particle will obey Newton's third law LOCALLY and will exert an equal and opposite CONTACT LOCAL INERTIAL REACTION FORCE on the ACCELERATING AGENT ( to use Jim's phrasing).

In some cases, e.g. the CYCLOTRON PROBLEM that electrical inertial reaction force will be outward centrifugal on the magnetic flux mr x w x w = (e/c)v x B where v = rw in the tangential direction of the circular orbit of period  1/w.

Now this term the real electrical local contact inertial reaction force mr x w x w in Case 2 MIMICs a term in the fictitious force Case 1 for the rotating non-inertial frame B (do not confuse with magnetic field pseudo-vector in BOLD FACE) where:


A is the inertial frame, and B is the rotating frame.

On Dec 26, 2012, at 4:44 PM, Paul Zielinski <This email address is being protected from spambots. You need JavaScript enabled to view it.> wrote:

On 12/26/2012 12:34 PM, JACK SARFATTI wrote
I .Z I think you & Jim are seriously confused on the concept of inertial forces so much so that your views are not even wrong in Pauli's sense - indeed mystical in the worst sense of the word. If I am right, then Jim's entire scheme for Mach propulsion seems fatally flawed. I am withholding final judgement till I real more in his new Star Ship book.