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Inge Lehmann’s quest to discover the mystery of the earth’s core

Quick notes:

  • Inge Lehmann was a Danish scientist in the early 20th century

  • She received degrees in math and went on to become a world-renowned earthquake studier

  • Lehmann discovered that the earth’s core is solid, not a liquid core like was previously believed

Inge Lehmann’s story is an inspiring one for any woman pursuing science. This Danish scientist’s passion for science and her ability to overcome all obstacles made her one of the greatest scientists of all time, and we should all be thanking her for her dedication (especially if you live in an earthquake zone).

Who was Inge Lehmann?

Lehmann was born in Copenhagen, Denmark in 1888, a time when it was rough to be a scientifically-minded girl. Luckily, her parents were progressive (and pretty science-inclined themselves: her dad studied experimental psychology and her grandpa pioneered the laying of telephone lines), so Lehmann attended the very first co-ed school in the country where she got to experiment, explore, and explain to her heart’s content.

Unfortunately, she found the rest of the world to be less accepting. Still, Lehmann pushed on, unwilling to let simple sexism stand in her way.

After receiving both a Bachelor’s degree and a Master’s degree, both in math, Lehmann finally began her work in seismology, the field that would make her famous. She started off working as an assistant to a mathematician at the Royal Danish Geodetic Institute, and when her boss was sent to Greenland to monitor seismometers, she went along. This choice would change her life.

What is seismology, and what did Inge Lehmann do to revolutionize it?

Seismology is the study of earthquakes and other events connected to movement under the Earth’s surface. When Lehmann started her seismographic work in 1925, the field wasn’t particularly advanced: observatories collected readings from seismographs that gave scientists data about the condition of Earth’s innards. But Lehmann quickly realized that the readings she was reading weren’t lining up with mainstream what’s-in-the-earth theories.

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Being the innovator she was, Lehmann took it upon herself to find out. She had only been working with seismology since 1925, but she was appointed Chief of the Royal Danish Geodetic Institute’s seismological department in 1928 because of her diligent and creative work. As chief, she started picking apart the commonly held idea that Earth’s core was all molten (liquid) rock; her data from the seismographs didn’t support that theory, as much as everyone else wanted to believe it.

In 1929, seismographers in Europe picked up waves from an earthquake in New Zealand. After analyzing the data (and drawing diagrams on the backs of oatmeal cereal boxes), Lehmann had a revolutionary idea. She realized that in order for earthquake waves to travel all the way across the planet, the center of the earth couldn’t be all liquid. There had to be a sphere of solid rock at Earth’s core instead.

… the center of the earth couldn’t be all liquid. There had to be a sphere of solid rock at Earth’s core instead.

It didn’t take long for Lehmann’s fellow scientists to realize that she was right. Lehmann published her first paper on her not-entirely-liquid core idea in 1936, and the theory was quickly adopted and verified by scientists around the world.

What is Inge Lehmann’s legacy?

Lehmann didn’t just show the world what is at its center, but she has also inspired countless people to show the world what they are all about. She was a pioneer in a male-dominated science world, and what she discovered literally changed the way we see the world. Follow your passions and take the time to learn even if no one will teach you: be like Lehmann.

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