  The ground-based gravitational wave (GW) detectors LIGO and Virgo have
enabled the birth of multi-messenger GW astronomy via the detection of GWs from
merging stellar-mass black holes (BHs) and neutron stars (NSs). GW170817, the
first binary NS merger detected in GWs and all bands of the electromagnetic
spectrum, is an outstanding example of the impact that GW discoveries can have
on multi-messenger astronomy. Yet, GW170817 is only one of the many and varied
multi-messenger sources that can be unveiled using ground-based GW detectors.
In this contribution, we summarize key open questions in the astrophysics of
stellar-mass BHs and NSs that can be answered using current and
future-generation ground-based GW detectors, and highlight the potential for
new multi-messenger discoveries ahead.
