If I Am Right, and I Know I Am: Inge Lehmann, the Woman Who Discovered Earth's Innermost Secret

In the 1930s, the pioneering Danish scientist Inge Lehmann (1888–1993) made a groundbreaking discovery about the nature of Earth. Analyzing data from earthquakes, she determined that the heart of the planet is a solid inner core. Her discovery overturned the widely accepted theory of the core being fluid, but she trusted her calculations: “If I am right, and I know I am,” she wrote in a letter. A fiercely independent thinker, Lehmann forever changed our understanding of our planet.

If I Am R...