What is the actual difference between a four digit and six digit grid reference?

A 6-figure grid reference contains 6 numbers which gives us an even more precise location inside the box given by the 4-figure number. ... The third number represents how many tenths you need to move east from the easting value. In our 6-number example, our third number is 4, which represents four-tenths more to the east.

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.