ALD22: Inge Lehmann, Seismologist and Geophysicist

Inge Lehmann

Inge Lehmann

Inge Lehmann was a seismologist and geophysicist who discovered that the Earth has a solid inner core and a molten outer core.

Born in Copenhagen in 1888, in 1907 she began studying mathematics, chemistry and physics at the University of Copenhagen and University of Cambridge, but had to take a break due to ill-health. She resumed her study of mathematics at Cambridge in 1910, before exhaustion enforced another break, eventually restarting her education at Copenhagen University in 1918, graduating in 1920.

Her interest in seismology began when she got a job as an assistant to Niels Erik Nørlund, a geodesist. She was tasked with setting up seismological observatories in Denmark and Greenland, which prompted her to study seismology. She earnt her magister scientiarum, equivalent to a master’s degree, in geodesy in 1928 and took a position as a geodesist and head of the department of seismology at the Geodetical Institute of Denmark. She was responsible for analysing the seismograph data, recording the seismic wave arrival times ready for publication in international bulletins. This data was fundamental to much of the era’s seismological research.

In 1936, she found evidence of P-waves appearing in the shadow of the Earth’s core, which she interpreted as showing that there was an inner core. At the time, it was thought that the Earth’s core was liquid, but an earthquake in New Zealand resulted in P-waves arriving at seismic stations that should have been blocked by this liquid core. Lehmann’s theory was that these P-waves had been refracted by some sort of boundary, which had to mean that there was a solid inner core and a liquid outer core.

Although this interpretation was adopted within a few years, it was not shown to be correct until 1971 when computer calculations using data from more sensitive seismographs could verify her work. Lehmann had to do all of her data collection and calculations by hand, creating boxes of cards, each with data from earthquakes around the world.

Although her work was interrupted by World War II, she served as Chair of the Danish Geophysical Society in both 1940 and 1944.

In the early 1950s, she moved to the US and began investigating the Earth’s crust and upper mantle. A decade later, she discovered a seismic discontinuity, where seismic waves change speeds, at between 190 and 250 km which is now known as the Lehmann Discontinuity. This discovery was made through “exacting scrutiny of seismic records by a master of a black art for which no amount of computerization is likely to be a complete substitute”, as geophysicist Francis Birch put it.

Lehmann received many awards over the years. She was elected as a Fellow of the Royal Society in 1969, was the first woman to win the William Bowie Medal in 1971, and was awarded the Medal of the Seismological Society of America in 1977. The American Geophysical Union began awarding the Inge Lehmann Medal to honour “outstanding contributions to the understanding of the structure, composition, and dynamics of the Earth’s mantle and core” in 1997. In 2015, the asteroid 5632 Ingelehmann was named after her, as was a new beetle species, Globicornis (Hadrotoma) ingelehmannae.

She died in 1993, aged 104.

Further Reading

ALD22 Books: Fire and Ice, Dr Natalie Starkey

Fire and Ice: The Volcanoes of the Solar System, Dr Natalie Starkey

The volcano is among the most familiar and perhaps the most terrifying of all geological phenomena. However, Earth isn’t the only planet to harbour volcanoes. In fact, the solar system, and probably the entire universe, is littered with them. Our own moon, which is now a dormant piece of rock, had lava flowing across its surface billions of years ago, while Mars can be credited with the largest volcano in the solar system, Olympus Mons, which stands 25km high. While Mars’s volcanoes are long dead, volcanic activity continues in almost every other corner of the solar system, in the most unexpected of locations.

We tend to think of Earth volcanoes as erupting hot, molten lava and emitting huge, billowing clouds of incandescent ash. However, it isn’t necessarily the same across the rest of the solar system. For a start, some volcanoes aren’t even particularly hot. Those on Pluto, for example, erupt an icy slush of substances such as water, methane, nitrogen or ammonia, that freeze to form ice mountains as hard as rock. While others, like the volcanoes on one of Jupiter’s moons, Io, erupt the hottest lavas in the solar system onto a surface covered in a frosty coating of sulphur.

Whether they are formed of fire or ice, volcanoes are of huge importance for scientists trying to picture the inner workings of a planet or moon. Volcanoes dredge up materials from the otherwise inaccessible depths and helpfully deliver them to the surface. The way in which they erupt, and the products they generate, can even help scientists ponder bigger questions on the possibility of life elsewhere in the solar system.

Fire and Ice is an exploration of the solar system’s volcanoes, from the highest peaks of Mars to the intensely inhospitable surface of Venus and the red-hot summits of Io, to the coldest, seemingly dormant icy carapaces of Enceladus and Europa, an unusual look at how these cosmic features are made, and whether such active planetary systems might host life.

Order the book on here and your purchase will support a local independent bookshop of your choice!

About the Author

Natalie Starkey is a science communicator and writer, and is Science Media Producer for Chemistry World at Royal Society of Chemistry. Following a PhD at University of Edinburgh studying the geochemistry of Arctic volcanoes, Natalie’s post-doctoral work at The Open University shifted her research focus to comet and asteroid samples. It was at this time she got the chance to analyse samples returned by the NASA Stardust and JAXA Hayabusa space missions.

Natalie’s passion for her research makes her a keen science communicator. She received a British Science Association Media Fellowship in 2013, and regularly appears on television and radio internationally, as well as being a science host on Neil deGrasse Tyson’s popular StarTalk Radio. Her writing includes her previous book Catching Stardust: Comets, Asteroids and the Birth of the Solar System as well as numerous articles for The Guardian, BBC Focus, All About Space and New Scientist. Additionally, she is a regular contributor to The Conversation.

You can follow her work here:

Twitter: @starkeystardust
Instagram: @StarkeyStardust
Facebook: @StarkeyStardust

ALD22: Professor Edith Clarke, Electrical Engineer

Edith Clarke

Professor Edith Clarke

Edith Clarke was an electrical engineer who was the first woman to become a professor of electrical engineering in the USA and developed a method to calculate the maximum power that a transmission line could carry and remain stable.

Clarke was born in Maryland in 1883. After being orphaned at the age of 12, she was raised by her sister and used her inheritance to study mathematics and astronomy at Vassar College. In 1911, she began studying civil engineering at the University of Wisconsin–Madison, but she took a summer job as a human ‘computer’ at AT&T at the end of her first year and enjoyed it so much that she stayed there to train other computers.

She studied electrical engineering at Columbia University in her evenings, then went on to become the first woman to earn a master’s degree in electrical engineering from the Massachusetts Institute of Technology.

She found it difficult to get work as an engineer after graduation, so worked for General Electric, supervising computers. She invented and patented an early graphing calculator, called the Clarke Calculator, which solved equations involving hyperbolic functions ten times faster than other methods.

In 1921, frustrated by a lack of opportunity and equality, Clarke moved to Turkey for a year to teach at the Constantinople Women’s College. When she returned to the USA, GE offered her a position as an electrical engineer, and she became the first professional female electrical engineer in the country.

She also became the first woman to present a paper at the American Institute of Electrical Engineers’ (AIEE) annual meeting. Her paper explained how to calculate the maximum power that a line could carry and remain stable, which became very important as the energy grid grew. The AIEE also awarded her the Best Regional Paper Prize in 1932 and the Best National Paper Prize in 1941, and her work underpinned much of the industry’s understanding of how to deal with power and transmission.

Clarke worked on the West Hoover Dam, developing and installing the hydroelectric turbines.

She also lectured GE engineers, and wrote a textbook based on those lectures, Circuit Analysis of A-C Power Systems, which became a standard text for years. In it, she describes the mathematical methods for addressing power system losses and electrical equipment performance.

In 1947, she became the first female professor of electrical engineering in the USA when she joined the Electrical Engineering Department at the University of Texas at Austin. She taught at Austin until her retirement in 1957

In 1948, she became the first female Fellow of the American Institute of Electrical Engineers, and was the first female full voting member in the American Institute of Electrical Engineers. In 1954, she was given the Society of Women Engineers’ Achievement Award. In 2015, she was posthumously inducted into the National Inventors Hall of Fame.

She died in 1959, aged 76.

Further Reading

ALD22 Podcasts: The Caring Scientist, Adriana Wolf & Nikoline Borgermann

The Caring Scientist, Adriana Wolf & Nikoline Borgermann

Laboratories are leaving behind a massive ecological footprint that isn’t exactly improving the state of our planet. But what can wet-lab scientists do to reduce their environmental impact? And is it possible to go green in the lab without compromising research? In this podcast, Adriana Wolf & Nikoline discuss obstacles and solutions related to sustainability in science, and give you hands-on tips on how to reduce the environmental impact of your lab work without compromising research.

Recent episodes covered: 

  • Nikolaj Lervad Hansen and Ann Schirin Mirsanaye from the University of Copenhagen to talk about how they adjusted their freezer temperature from -80C to -70C.
  • Hannah Johnson from Green Labs Netherlands talks about how the network started and what they are doing. 
  • Raj Patey from My Green Lab talks about sustainable products and procurement
  • CEO of the non-profit organisation Seeding Labs, Melissa Wu, discusses how donating surplus lab equipment helps ecological sustainability and social equity in science. 
  • A discussion of sustainable conferencing and air travel in academia with Kate Whitfield, sustainability expert at ISGLOBAL, and Teun Bousema, Professor at Radboud University Medical Centre Nijmegen.

You can:

Listen on Spotify
Follow on Twitter: @caringscientist @AvaSustain @AdrianaWolfPer1 

ALD22: Professor Flossie Wong-Staal, Virologist and Molecular Biologist

Flossie Wong-Staal

Professor Flossie Wong-Staal

Professor Flossie Wong-Staal, née Wong Yee Ching, 黄以静, was a virologist and molecular biologist who was the first to molecularly clone Human Immunodeficiency Virus (HIV) and created a map of its genes, which was crucial to proving that HIV causes Acquired Immunodeficiency Syndrome (AIDS).

Born in Guangzhou, China, in 1946, she and her family fled to Hong Kong after the Communist Revolution during the late 1940s. When she was 18. Wong-Staal moved to California to study bacteriology at the University of California, Los Angeles, then moved to San Diego for her postdoctoral research before moving to the National Cancer Institute in Maryland in 1973, where she refocused her research on retroviruses.

She discovered that human T-lymphotropic virus, HTLV-1 was the cause of T cell leukaemia, proving that retroviruses can cause human disease. Her work showed that the virus affected human DNA, activating cancer-causing genes called oncogenes.

She went on to work on a new disease that was very similar to HTLV-1, and in 1975, she successfully cloned HIV. She mapped the virus’s genome which both revealed how genetically diverse HIV is, but also allowed the development of blood tests based on detection of the viral genome rather than virus antibodies. She became a world leader in HIV research, studying its genetic structure, replication strategies and regulatory mechanisms.

She published over 400 papers on human retroviruses and AIDSand was the most-cited female scientist of the 1980s. In 1990, the Institute for Scientific Information named her as the top woman scientist of the 1980s.

In 1990, she founded the Centre for AIDS Research at UCSD. Her research focused on gene therapy and on HIV-1’s relationship to Kaposi’s sarcoma, which is a common ailment for people with AIDS.

Wong-Staal became professor emerita upon retirement from UCSD in 2002, and cofounded Immusol (later iTherX Pharmaceuticals), a biopharmaceutical company, becoming its chief scientific officer. She worked there on improving drugs for hepatitis C.

She was inducted into the National Women’s Hall of Fame in 2016, and Discover named her one of the 50 “most extraordinary women scientists” in 2002.

Wong-Staal died on 8 July 2020, aged 73.

Further Reading