Inge Lehmann – discoverer of Earth’s inner core – honoured in Google Doodle

13 May 2015

Inge Lehmann, Google Doodle honoree

Google has honoured pioneering seismologist and geophysicist Inge Lehmann – who discovered the Earth’s core – with an impressive animated Doodle.

Lehmann, who was born on 13 May 1888, has been honoured in an animated Doodle that illustrates her discovery that the Earth had an inner core that was distinct from its outer core.

In 1936 she postulated from existing seismic data that the Earth’s core is not a single molten sphere but that an inner core exists that has physical properties different from those in the outer core.

Lehmann grew up in Copenhagen and studied maths at the University of Copenhagen and the University of Cambridge. Overcoming health problems, she developed good computational skills while working at an actuary office and returned to university where she completed a magisterii degree in physical science and maths within two years.

Inge Lehmann Google doodle of Earth's core

She developed an interest in seismology and while working at the Geodetical Institute of Denmark she was the first to interpret P wave arrivals that inexplicably appeared in the P wave shadow of the Earth’s core as reflections of an inner core.

Her work was interrupted by the occupation of Denmark by Nazi German forces but renewed with relish after the war. However, her patience with less competent male colleagues at the Geodetical Instituten led to her departure in 1953. She famously commented: “You should know how many incompetent men I had to compete with — in vain.”

She moved to the US to collaborate with Maurice Ewing and Frank Press on investigations into the Earth’s crust and upper mantle.

During this time she discovered another seismic discontinuity that lies at depths of between 190 and 250km and which was named the Lehmann Discontinuity in her honour.

The asteroid 5632 has also been named in Lehmann’s honour. Lehmann died in February 1993 at the age of 105.

John Kennedy is a journalist who served as editor of Silicon Republic for 17 years