  In any Big Bang cosmology, the frequency $\omega$ of light detected from a
distant source is continuously and linearly changing (usually redshifting) with
elapsed observer's time $\delta t$, because of the expanding Universe. For
small $\delta t$, however, the resulting $\delta\omega$ shift lies beneath the
Heisenberg frequency uncertainty. And since there {\it is} a way of telling
whether such short term shifts really exist, if the answer is affirmative we
will have a means of monitoring radiation to an accuracy level that surpasses
fundamental limitations. More elaborately, had $\omega$ been `frozen' for a
minimum threshold interval before any redshift could take place, i.e. the light
propagated as a smooth but {\it periodic} sequence of wave packets or pulses,
and $\omega$ decreased only from one pulse to the next, one would then be
denied the above forbiddingly precise information about frequency behavior. Yet
because this threshold period is {\it observable}, being $\Delta t \approx
1/\sqrt{\omega_0 H_0} \sim$ 5 -- 15 minute for the cosmic microwave background
(CMB), we can indeed perform a check for consistency between the Hubble Law and
the Uncertainty Principle. If, as most would assume to be the case, the former
either takes effect without violating the latter or not take effect at all, the
presence of this characteristic time signature (periodicity) $\Delta t$ would
represent direct verification of the redshift phenomenon.
