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Re: [Phys-l] Inertia? - Reprise



At 01:14 AM 11/15/2008, David B., you wrote:

[bw]
>....I find myself disappointed for missing an opportunity
>for a little exploration at a junior high level -

[db]
When it comes to the ability of an object to produce a spacetime
curvature (i.e. a real gravitational field) the relevant property
of the object is not its mass, per se, but the components of its
4x4 stress-energy-momentum tensor. These components are the energy
density (the time-time component), the stress (including the
pressure, shear & anisotropic compression/tension, the space-space
components), and the momentum density (or energy current density,
the time-space components).


The 4x4 stress-energy-momentum tensor sounds like a SERIOUS
tool for transforming dynamic coordinate systems etc.
I recall a 3X3 matrix is adequate to transform the 'inertial' to
body-centered dynamics of flight simulators.
So this more elaborate tool should be useful in the analytical
solution of say, the general three body celestial orbit system
with time....
But apparently, it cannot.

Strange that a tool suited to analyzing the grand sweep of
space, time, mass and momentum can fail for three bodies.
[if true, at least]
There must be a deep reason?

Brian Whatcott Altus OK Eureka!