  We show that Fano interference explains how point contact spectroscopy in
heavy electron materials probes the emergence of the Kondo heavy electron
liquid below the same characteristic temperature T* as that seen in many other
experiments, and why the resulting measured conductance asymmetry reflects the
universal Kondo liquid behavior seen in these. Its physical origin is the
opening of a new channel for electron tunneling beyond that available from the
background conduction electrons. We propose a simple phenomenological
expression for the resulting Fano interference that provides a good fit to the
experimental results for CeCoIn$_5$, CeRhIn$_5$ and YbAl$_3$, over the entire
range of bias voltages, and deduce a life-time of the heavy quasiparticle
excitations that agrees well with recent state-of-the-art numerical
calculations.
