In my game there is a high level wizard conjurer. He wants to cast a force wall around himself and the party, then use minor conjuration to create 10 pounds of the center of the sun, which he scried earlier, outside of his wall of force.

I'm wondering if this is even possible or if there's some rule limitation. If it is possible, can I have an idea of the amount of TNT this is? Would the explosion pass through the wall of force? What about the sound waves? Would the party go blind due to the explosion? What about the warforged?

They also had this idea to conjure a milligram of the centre of the sun right in front of a guy's face. How destructive would that be? Right now I've said no to conjuring it, but not because I don't want him to do it just because I want to know, will this blow up the country, a city, a small house, the surrounding area or what? And what about the milligram -- would that blow up the guy's head or the entire party, or do effectively nothing.