A Measurement of the Cosmic Expansion Within our Lifetime
  The most exciting future observation in cosmology will feature a monitoring
of the cosmic expansion in real time, unlike anything that has ever been
attempted before. This campaign will uncover crucial physical properties of the
various constituents in the Universe, and perhaps answer a simpler question
concerning whether or not the cosmic expansion is even accelerating. An
unambiguous yes/no response to this query will significantly impact cosmology,
of course, but also the standard model of particle physics. Here, we discuss --
in a straightforward way -- how to understand the so-called `redshift drift'
sought by this campaign, and why its measurement will help us refine the
standard-model parameters if the answer is `yes.' A `no' answer, on the other
hand, could be more revolutionary, in the sense that it might provide a
resolution of several long-standing problems and inconsistencies in our current
cosmological models. An outcome of zero redshift drift, for example, would
obviate the need for a cosmological constant and render inflation completely
redundant.
