Inge Lehmann, a pioneering Danish seismologist, made a groundbreaking discovery in 1936 that significantly advanced our understanding of the Earth’s internal structure. The early 20th century saw seismologists deploying a global network of sensitive earthquake monitoring systems. These systems, capable of detecting seismic waves from both local and distant earthquakes, played a crucial role in revealing the Earth’s layered structure, consisting of the core, mantle, and crust.
Lehmann’s analysis of seismic data led to the hypothesis that the Earth’s core is composed of two distinct parts: a liquid outer core and a solid inner core. This was a significant departure from the then-prevailing belief of a uniformly molten core, influenced by the Earth’s strong magnetic field. Lehmann’s findings, though initially met with skepticism, were soon widely accepted by the geological community, marking a major achievement in seismology.
Her work not only reshaped our understanding of the Earth’s interior but also stood as a testament to her perseverance in a predominantly male-dominated field. Today, the enhanced global seismometer network continues to refine our model of the Earth’s internal structure, providing detailed insights into the composition and boundaries of the inner and outer core, as well as the mantle.