  It has been known for over 30 years that Galactic globular clusters (GCs) are
overabundant by orders of magnitude in bright X-ray sources per unit mass
relative to the disk population. Recently a quantitative understanding of this
phenomenon has developed, with a clear correlation between the number of X-ray
sources in a cluster, $N_X$, and the cluster's encounter frequency, $\Gamma$,
becoming apparent. We derive a refined version of $\Gamma$ that incorporates
the finite lifetime of X-ray sources and the dynamical evolution of clusters.
With it we find we are able to explain the few clusters that lie off the
$N_X$--$\Gamma$ correlation, and resolve the discrepancy between observed GC
core radii and the values predicted by theory. Our results suggest that most
GCs are still in the process of core contraction and have not yet reached the
thermal equilibrium phase driven by binary scattering interactions.
