Evidence That Convinced

Wegener's idea was mocked for decades. What proved him right was paleomagnetism — rocks record Earth's magnetic field as they form.

In the 1960s, scientists found symmetrical magnetic stripes on either side of mid-ocean ridges. As new crust formed and spread apart, it captured alternating polarities like a tape recorder, undeniable proof of seafloor spreading.

GPS in the 1990s sealed it, directly measuring continents in motion. Australia creeps north about 7 cm per year. Wegener's wild idea now had satellite precision behind it.