Navigating the past with ancient stone compass needles

Magnetic rocks with iron oxide concentrations act as natural chroniclers of Earth's past continental movements. Using small samples of rocks, scientists can isolate magnetic grains that were frozen in orientation as the rock solidified. The magnetization of these grains acts as a miniature compass needle, pointing toward ancient magnetic poles. This same principle applies to extraterrestrial samples, such as meteorites and lunar rocks, which preserve evidence of the early solar nebula's evolution.