Earth's magnetic field can help archaeologists sniff out forged antiquities

Earth's magnetic field not only safeguards our planet from cosmic radiation but may also aid archaeologists in identifying authentic ancient artifacts, according to researchers. The new technique applies to fired clay objects and hinges on their ability to capture a weak magnetic signature known as Viscous Remnant Magnetization, or VRM.

This residual magnetization results from the clay's interaction with Earth's magnetic field after prolonged exposure. While older artifacts exhibit a stronger VRM, modern items lose this signal at lower temperatures. Researchers from the University of California San Diego, led by Dr. Yoav Vaknin and Prof. Lisa Tauxe, tested 45 clay items—comprising ancient and modern pieces—to validate this method.

They found that modern artifacts display a loss of VRM at lower temperatures (below 112 degrees Celsius, or 233 degrees Fahrenheit), whereas ancient artifacts retain this signal until higher temperatures. Thus, if an artifact's VRM is eliminated above 112 degrees Celsius, it can be reasonably assumed to be at least a thousand years old.

This innovation presents a promising tool for authenticating disputed artifacts, although it primarily benefits the authentication of ancient pieces and is less effective for medieval items.