  We write in response to the call from the 2020 Decadal Survey to submit white
papers illustrating the most pressing scientific questions in astrophysics for
the coming decade. We propose exploration as the central question for the
Decadal Committee's discussions.The history of astronomy shows that paradigm
changing discoveries are not driven by well formulated scientific questions,
based on the knowledge of the time. They were instead the result of the
increase in discovery space fostered by new telescopes and instruments. An
additional tool for increasing the discovery space is provided by the analysis
and mining of the increasingly larger amount of archival data available to
astronomers. Revolutionary observing facilities, and the state of the art
astronomy archives needed to support these facilities, will open up the
universe to new discovery. Here we focus on exploration for compact objects and
multi messenger science. This white paper includes science examples of the
power of the discovery approach, encompassing all the areas of astrophysics
covered by the 2020 Decadal Survey.
