Emil Wiechert

In 1897, Wiechert proposed a pioneering model of the Earth's interior featuring a dense metallic core surrounded by a lighter rocky mantle. This was the first scientifically credible theory suggesting the Earth was not uniformly composed.

Wiechert developed an inverted-pendulum seismograph that vastly improved the sensitivity and reliability of earthquake detection. This mechanical instrument became the global standard for seismic recording stations in the early 20th century.

Wiechert was a prominent professor at the University of Göttingen in Germany. At Göttingen, he founded the Institute of Geophysics in 1898, which became one of the world's premier hubs for early seismic and geophysical research.

While Wiechert correctly theorized a dense metallic core in 1897, he did not precisely map its boundaries. It was his former student, Beno Gutenberg, who used seismic waves to accurately calculate the depth of the core-mantle boundary in 1914.