By studying what was once an iron smelting site in Cambodia, archaeologists and earth scientists unveiled a sharp change in Earth’s geomagnetic field direction and strength that occurred about 10 centuries ago. The new data, published this week in the journal Proceedings of the National Academy of Sciences, marks the first archaeomagnetism records from southeastern Asia. The researchers believe it will fill gaps in scientists’ understanding of Earth’s past magnetism, illuminating how the planet’s protective sheath may change in the future... Tauxe worked with Mitch Hendrickson, an archaeologist at the University of Illinois at Chicago, who was excavating an iron-smelting...