  There are observations indicating a possible anomalous transparency of
intergalactic space (filled with infrared background light) for extragalactic
gamma-rays of very high energy (> 100 GeV). The anomaly is usually associated
with effects of some new physics. However, another explanation is possible --
as a manifestation relating to a cut-off of the zero-point vibration spectrum.
It is assumed that this boundary U_{ZV} is isotropic in the reference frame,
where the cosmic microwave background (CMB) radiation is isotropic, and an
estimate is obtained: U_{ZV} ~7.4 TeV. The presence of a ZV boundary also leads
to an increased beta decay time of accelerated particles with the Lorentz
factor > 50. It is widely believed that the ZV-spectrum continues up to the
Planck energy. There is, however, a 5D variant of the Absolute Parallelism
theory (AP), free from singularities of solutions, where a large characteristic
length L appears, which determines the thickness of expanding spherical
S^3-shell (the cosmological solution as the longitudinal wave along the radius)
in co-moving co-ordinates. Newton's Law 1/r^2 is replaced by 1/r at distances
exceeding L, and the Planck length (a composite parameter) `arises' from L when
switching to the conventional energy-momentum scale. The theory features are
briefly exposed -- description of 15 polarizations (degrees of freedom), the
energy-momentum tensor (in prolonged 4th order equations), topological charges
and quasi-charges of localized field configurations.
