With the detection of compact binary coalescences and their electromagnetic counterparts by gravitational-wave detectors, a new era of multi-messenger astronomy has begun. In this talk, I will describe how the gravitational-wave community is using these mergers to constrain the unknown equation of state of cold supranuclear matter, and to measure the Hubble constant. I will then discuss how current ground based optical surveys and dedicated follow-up systems are being used to identify more of these, and how we are developing models to test what we find. We will close with near-term prospects for the field.

This lecture was made possible by the William C. Ferguson Fund.