In the mid 1930s, this geophysics and seismology expert made the groundbreaking discovery that our planet's outer core is molten and its inner core solid.
She was a mathematics student at both Cambridge University and the University of Copenhagen. After graduating, she became head of the Geodetical Institute of Denmark's seismology unit.
Her numerous honors include the 1971 william Bowie Medal, the 1960 Gordon Wood Award, and the 1977 Medal of the Seismological Society of America.
She and Charles Richter were both notable seismologists of the early twentieth century.