  Heavy ion experiments provide important data to test astrophysical models.
The high density equation of state can be probed in HI collisions and applied
to the hot protoneutron star formed in core collapse supernovae. The Parity
Radius Experiment (PREX) aims to accurately measure the neutron radius of
$^{208}$Pb with parity violating electron scattering. This determines the
pressure of neutron rich matter and the density dependence of the symmetry
energy. Competition between nuclear attraction and coulomb repulsion can form
exotic shapes called nuclear pasta in neutron star crusts and supernovae. This
competition can be probed with multifragmentation HI reactions. We use large
scale semiclassical simulations to study nonuniform neutron rich matter in
supernovae. We find that the coulomb interactions in astrophysical systems
suppress density fluctuations. As a result, there is no first order liquid
vapor phase transition. Finally, the virial expansion for low density matter
shows that the nuclear vapor phase is complex with significant concentrations
of alpha particles and other light nuclei in addition to free nucleons.
