  The glass transition remains one of the great unsolved mysteries of
contemporary condensed matter physics. When crystallization is bypassed by
rapid cooling, a supercooled liquid, retaining amorphous particle arrangment,
results. The physical phenomenology of supercooled liquids is as vast as it is
interesting. Most significant, the viscosity of the supercooled liquid displays
an incredible increase over a narrow temperature range. Eventually, the
supercooled liquid ceases to flow, becomes a glass, and gains rigidity and
solid-like behaviors. Understanding what underpins the monumental growth of
viscosity, and how rigidity results without long range order is a long-sought
goal. Many theories of the glassy slowdown require the growth of static
lengthscale related to structure with lowering of the temperature. To that end,
we have proposed a new, natural lengthscale- "the shear penetration depth".
This lengthscale quantifies the structural connectivity of the supercooled
liquid. The shear penetration depth is defined as the distance up to which a
shear perturbation applied to the boundary propagates into the liquid. We
provide numerical data, based on the simulations of $NiZr_2$, illustrating that
this length scale exhibits dramatic growth and eventual divergence upon
approach to the glass transition. We further discuss this in relation to
percolating structural connectivity and a new theory of the glass transition.
