What is the mechanism that causes the outward explosion in a core-collapse supernova?

Answer

The violent rebound of outer layers off the incompressible neutron core

When the collapsing outer layers hit the suddenly rigid, incompressible neutron core, they violently rebound, sending a powerful shockwave outward that blasts the star's material into space, creating the visible supernova event.

What is the mechanism that causes the outward explosion in a core-collapse supernova?
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