With an estimated 1.6 billion tonnes of water ice at its poles and an abundance of rare-earth elements hidden below its (A) s______,the Moon is rich ground for mining.In this month's issue of Physics World,science writer Richard Corfield explains how private (l) c and space agencies are dreaming of tapping into these lucrative (利可图的) resources and turning the Moon's grey landscape into a money-making conveyer belt.