Thursday, March 6, 2025

What's a "null-strut grid" -- and how exactly does this show in the header picture of an "octet truss" ? (0sg-1)

 


1 comment:

  1. The drawing is of an (arbitrarily extended) "octet truss" 3D space frame ( open access taken from https://www.mdpi.com/2075-4701/12/3/410 ); see also tetrahedral-octahedral honeycomb.

    Interpreted as illustration of a (3+1) dimensional null-strut-grid:

    - each individual vertex depicts the individual time-like world line of a suitably selected "material point" (in the sense of [Einstein-1916]; [Minkowski-1908] ...); a.k.a. a "constituent" (of the null-strut-grid being shown), and

    - each edge segment depicts continuous signal (front) exchange between relevant pairs of those material points; implying the causal structure of a "photon-2-surface", see [gr-qc/0306042];
    or, being only a limited segement, rather: a "photon ribbon";
    and thereby also a certain set of "null-struts" (in the sense of [Kheyfets-1988]).

    In the corresponding (arbitrarily extended) null-strut-grid, for each constituent these null-struts are required (and selected such that) ping-coincidence relations are found and satisfied

    - wrt. the 12 nearest neighbors,

    - wrt. the 6 next-to-nearest neighbors,

    - wrt. the 12 next-to-next-to-nearest neighbors, etc.

    Each constituent is thereby also identified as "the middle between" (in the sense of [Comstock-1910] and of [Einstein-1917]) six different (and even disjoint) pairs of its nearest neighbors (where the two constituents making up any such pair are in turn next-to-next-to-nearest neighbors of each other).

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