  Supernovae are Nature's high-energy, high density laboratory experiments,
reaching densities in excess of nuclear densities and temperatures above 10MeV.
Astronomers have built up a suite of diagnostics to study these supernovae. If
we can utilize these diagnostics, and tie them together with a theoretical
understanding of supernova physics, we can use these cosmic explosions to study
the nature of matter at these extreme densities and temperatures. Capitalizing
on these diagnostics will require understanding a wide range of additional
physics. Here we review the diagnostics and the physics needed to use them to
learn about the supernova engine, and ultimate nuclear physics.
