  The phenomenon of cosmic shear, or distortion of images of distant sources
unaccompanied by magnification, is an effective way of probing the content and
state of the foreground Universe, because light rays do not have to pass
through mass structures in order to be sheared. It is shown that the delay in
the arrival times between two simultaneously emitted photons that appear to be
arriving from a pair of images of a strongly lensed cosmological source
contains not only information about the Hubble constant, but also the long
range gravitational effect of galactic scale mass clumps located away from the
light paths in question. This is therefore also a method of detecting shear.
Data on time delays among a sample of strongly lensed sources can provide
crucial information about whether extra dynamics beyond gravity and dark energy
are responsible for the global flatness of space. If the standard $\Lambda CDM$
model is correct, there should be a large dispersion in the value of $H_0$ as
inferred from the delay data by (the usual procedure of) ignoring the effect of
all other mass clumps except the strong lens itself. The fact that there has
not been any report of a significant deviation from the $h =$ 0.7 mark during
any of the $H_0$ determinations by this technique may already be pointing to
the absence of the random effect discussed here.
