On Aug 23, 2011, at 4:47 PM, Paul Zielinski wrote:
Of course the advantages of a local interaction model for inertia include being able to account for instantaneous isotropic inertial reaction in a natural, intuitive and mathematically straightforward manner.
Right.
On 8/23/2011 4:43 PM, Paul Zielinski wrote:
These kinds of questions are not hard to answer if it is assumed that we start in Minkowski SR with a "flat" inertial guide field, and then interpret the covariant "warping" of spacetime in GR as the objective physical modification of the pre-existing gravity-free inertial trajectories resulting from the influence of gravitating matter. Then the GR geodesics naturally serve as local dynamical references for forced motion in a 4D geometric model for gravity.
Right.
Exactly what physically maintains the motion of free test objects along the spacetime geodesics in a flat or a curved spacetime is an interesting question, but since we now accept the reality of the "physical vacuum", it seems natural to suppose that a deeper theory of gravity and inertia will explain this in terms of local interactions between moving matter and the gravitationally distorted vacuum.
No, it's the tensor curvature field that shapes the geodesics. You don't need a deeper theory for that.
I would say that the Higgs mechanism of the Standard Model could provide some clues, if gravity is conceived as a physical modification of the "flat" (gravity free) inertial guide field (modeled geometrically in GR in terms of 4D spacetime curvature).
Wake up and smell the coffee. The appendix in
http://journalofcosmology.com/SarfattiConsciousness.pdf
shows how to do that.
I think we are way beyond the point where where one could plausibly dismiss such ideas as the "idle metaphysics" of Newtonian absolute space. And I don't see how, as things stand, one could reasonably argue that the various "Machian" models for inertia are any less speculative.