National Geographic News, Reporting Your World Daily

Monday, November 23, 2009

Photo: Magnetic Field Weakening in Stages, Old Ships' Logs Suggest


Email to a Friend	<< Back to Full Story

A 15th-century nautical compass sits on display in the Canary Islands. New analysis of compass data from old ships' logs shows that Earth's magnetic field has been weakening in staggered steps and not in a continuous decline.

Photograph by Victor R. Boswell, Jr./NGS