Todays marks renowned Danish seismologist and geophysicist Inge Lehmann’s 127 birthday and Google is celebrating this day by dedicating their Google Doodle to her.
Lehmann is most famous for the discovery of Earth’s inner core by studying P-waves. P-waves are produced by earthquakes and travel through the Earth’s mantle (the liquid layer under the Earth’s crust). Before Lehmann’s discovery of the inner core, it was unknown to scientists why P-waves would slow down at certain points while traveling through the Earth. Lehmann proposed they must be travelling through a different medium, a solid inner core. P-waves cannot travel through solids as fast as they can through liquid so this idea was reasonable. Her hypothesis was quickly accepted by most seismologists at the time and is now seen in every diagram of the Earth.
On her way to this discovery, Lehmann faced many challenges to be a seismologist. In the early 20th century, woman were not permitted to enter the sciences. Fortunately, through perseverance, Lehmann found a way. She gained entry into the first co-ed school in Denmark studying mathematics, in which she earned a masters degree for. Five years later she was working at the Danish Geodetic Institute where she made her discovery of the inner core. While working there she did several studies across Europe and earned a second masters degree in geodesy, the study of the Earths size and its magnetic field. By 1929 she was the head of the seismology department at the institute. Lehmann went on to found the Danish Geophysical Society and became the fist woman to earn the Medal of the Seismological Society.
Lehmann overcame great odds to become a world-renowned seismologist and geophysicist and made one of the most important discoveries in understanding the layers of, not only our Earth, but other planets in our solar system. She has been so important to the study of the Earth and was at one point, the only seismologist in all of Denmark. So on her 127th birthday we say “Happy Birthday Inge Lehmann”.