  Recent Spitzer observations of the globular cluster M15 detected dust
associated with its intracluster medium. Surprisingly, these observations imply
that the dust must be very short-lived compared to the time since the last
Galactic plane crossing of the cluster.Here we propose a simple mechanism to
explain this short lifetime. We argue that the kinetic energy of the material
ejected during a stellar collision may be sufficient to remove the gas and dust
entirely from a cluster, or to remove the gas as a wind, in addition to
partially destroying the dust. By calculating the rate of stellar collisions
using an N-body model for the cluster, we find remarkable agreement between the
average time between collisions and the inferred dust lifetime in this cluster,
suggesting a possible close relation between the two phenomena. Furthermore, we
also obtain the birthrate of blue stragglers formed through collisions in M15.
By comparing with the observed number of blue stragglers, we derive an upper
limit for their average lifetime which turns out to be consistent with recent
model calculations, thereby lending further support to our model.
