sentences:  Also, the collapse of the inner core is halted by neutron degeneracy, causing the implosion to rebound and bounce outward.The energy of this expanding shock wave is sufficient to disrupt the overlying stellar material and accelerate it to escape velocity, forming a supernova explosion.The shock wave and extremely high temperature and pressure rapidly dissipate but are present for long enough to allow for a brief period during which the
  production of elements heavier than iron occurs.