Donna Elbert’s magnetic discovery
More than 60 years ago, a woman with no advanced training in mathematics created a theory for how planetary magnetic fields form. Her contribution was overlooked for decades but now, armed with modern techniques, astronomers are recognizing her powerful insight.
Donna Elbert worked with famed astrophysicist and Nobel laureate Subrahmanyan Chandrasekhar for more than 30 years at Yerkes Observatory in Wisconsin and the University of Chicago, starting in 1948. Throughout much of her career, Elbert was seen simply as a human computer — the term for people (mostly women) who cranked through numbers in the days before machines were capable of doing so. But in truth, she rapidly became an integral collaborator in his research.
In the early 1950s, she and Chandrasekhar tackled the complex physics of planetary magnetic fields, which are generated when the charged particles of liquid metals inside planets rotate and churn. Elbert was the first to notice that if the forces from the rotation and the magnetic field are roughly equal in strength, convection in the liquid interior forms neat, largescale circulation patterns instead of smaller, more turbulent ones. This is the sweet spot that lets a world host a strong global magnetic field like Earth’s — capable of shielding organisms from harmful radiation.
Though Elbert co-authored 18 other publications with Chandrasekhar, she was not credited as a co-author of the 1961 book in which this work appeared. Instead, Chandrasekhar acknowledged her contribution in a footnote — which most researchers overlooked.
Recently, Susanne Horn of Coventry University in the U.K. and Jonathan Aurnou of the University of California, Los Angeles, returned to Chandrasekhar and Elbert’s work, having noticed the footnote. In her honor, they named the scenario the Elbert range and built upon her original analysis with modern computing power. The results were published Aug. 10 in Proceedings of the Royal Society A.
The work may help scientists better understand Earth’s own magnetic field, as well as potentially point to exoplanets that could likewise sustain global magnetic fields strong enough to protect life.