She is a star of American science. A Stanford chair. A NASA collaborator. A role model for a generation of young researchers. But a chilling congressional investigation has found that celebrated geologist Wendy Mao quietly helped advance China's nuclear and hypersonic weapons programs – while working inside the heart of America's taxpayer funded research system. Mao, 49, is one of the most influential figures in materials science. She serves as Chair of the Department of Earth and Planetary Sciences at Stanford University, one of the most prestigious science posts in the country. Her pioneering work on how diamonds behave under...