Christian Science Monitor: Could hot rocks miles below the earth’s surface be the “killer app” of the energy industry? Google thinks so. It’s investing more than $10 million to develop new technology that would make this subterranean resource a widespread, economically viable competitor to fossil fuels. Geothermal heat could meet 10 percent of America’s energy needs by mid-century, according to the US Department of Energy. What’s more, it would not generate the climate-warming carbon emissions associated …