Core collapse supernovae are gigantic explosions of massive stars that radiate 99 % of their energy in neutrinos .
This provides a unique opportunity for large scale parity or charge conjugation violation .
Parity violation in a strong magnetic field could lead to an asymmetry in the neutrino radiation and recoil of the newly formed neutron star .
Charge conjugation violation in the neutrino-nucleon interaction reduces the ratio of neutrons to protons in the neutrino driven wind above the neutron star .
This is a problem for r-process nucleosynthesis in this wind .
On earth , parity violation is an excellent probe of neutrons because the weak charge of a neutron is much larger than that of a proton .
The Parity Radius Experiment ( PREX ) at Jefferson Laboratory aims to precisely measure the neutron radius of ^ { 208 } Pb with parity violating elastic electron scattering .
This has many implications for astrophysics , including the structure of neutron stars , and for atomic parity nonconservation experiments .