A strange chunk of metal that lay hidden in the soil for thousands of years may shed new light on one of the most mysterious cultures in ancient China.The approximately 3,000-year-old Sanxingdui artifact appears to be an axe-like object made of iron – which likely came to Earth from space in the form of a meteorite. It's an extraordinary discovery that sheds light both on the Sanxingdui culture and the use of iron for crafting precious objects long before iron smelting became widespread. "As the earliest Bronze Age meteoritic iron artefact found in Southwest China," writes a team led by...