What is the ruling on learning worldly sciences and military industries, is it an obligation upon Muslims, and is a Muslim rewarded for it?

Non-Shariah sciences, such as mining, agriculture, and other beneficial sciences, may become obligatory if Muslims need them, thus becoming a collective obligation (fard kifayah). The ruler may order these sciences to be pursued and assist their practitioners with what helps them benefit Muslims. These actions are considered acts of worship if the intention is righteous and purely for Allah; otherwise, they are merely permissible acts. They may become a collective obligation if the need arises, and the ruler should compel those qualified to undertake them.