  It is well-known that gravitational waves (GWs) undergo no absorption or
dissipation when traversing through a perfect fluid. However, in the presence
of a viscous fluid, GWs transfer energy to the fluid medium. In this essay, we
present a review of our recent series of results regarding the interaction
between gravitational waves and surrounding matter. Additionally, we examine
the impact of a viscous fluid shell on gravitational wave propagation, focusing
particularly on GW damping and GW heating. Furthermore, we explore the
significance of these effects in various astrophysical scenarios such as
core-collapse Supernovae and primordial gravitational waves.
