42. What happens to seismic waves as they travel through materials of differing
rigidities?

Shadow zones exist because the materials that make up Earth's interior are not uniform in rigidity. When seismic waves travel through materials of different rigidity, they change in both speed and direction. S waves do not reach the S wave shadow zone because cannot pass through the liquid outer core.

radiative zone

explanation    

radiative zone is the layer of the sun which energy is transferred away from the core by radiation. although, the core is the only part of the sun that produces an appreciable amount of heat through fusion. in fact, 99% of the energy produced by the sun takes place within 24% of the sun's radius.