Igne Lehman
Lived 1888 – 1993.
Inge Lehmann overturned the idea that our planet’s metallic core is
entirely molten liquid. She used mathematics to analyze the way energy
released by earthquakes travels through the earth.
She discovered something eternally concealed from the naked eye –
thousands of miles below our feet, at its center, the earth is solid. In
fact, it has a solid inner core and a liquid outer core.
Inge Lehmann is also remarkable in that she is one of the longest lived scientists in history, living to 104 years of age.
Beginnings
Inge Lehmann was born in Denmark’s capital city, Copenhagen, on May
13, 1888. Her father, Alfred Georg Ludvik Lehmann, was a psychologist
and her mother, Ida Sophie Tørsleff, was a housewife. Both parents came
from prominent families.
In 1928, Lehmann was appointed head of the Department of Seismology
at the Royal Danish Geodetic Institute, with responsibility for running
the Copenhagen, Ivigtut and Scoresbysund seismographic observatories.
Her job was administrative, but she made time for scientific
research, including improving the coordination and analysis of
measurements from Europe’s seismographic observatories. This was
important, because it ensured data from the observatories could be
better compared and interpreted. Lehmann’s actions to improve the
trustworthiness of measurements lay at the heart of her later discovery.
Dreaming of a World Deep Below
The interior of our planet has long held a fascination for philosophers and story tellers.
Some have speculated that another inhabited world lies beneath our own.
In 1864, Jules Verne published Journey to the Center of the Earth, describing the fictional adventures of explorers traveling under our planet’s surface.
It was a best-seller.
People wondered if the world Verne had described below our own could be real.
We now know the solid core Inge Lehmann discovered:
- is about the same temperature as the sun’s surface!
- is made of iron-nickel alloy
- is solid because of the enormous pressure from the outer layers of the earth pushing down on it
- has a radius of 1220 km, making it somewhat smaller than the moon
The End
Inge Lehmann died at the age of 104 on February 21, 1993. She had not
married and had no children. She left all of her possessions to The
Danish Academy.
