What physical process converts kinetic energy into the extreme thermal heat observed in a supernova remnant?

Answer

Rapid compression and heating as the blast wave slams into the interstellar medium (ISM)

The extreme heat is directly tied to the shock wave, which rapidly converts the kinetic energy of the outward-ejected material into thermal energy as it compresses the ambient gas.

What physical process converts kinetic energy into the extreme thermal heat observed in a supernova remnant?
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