Her work helped her boss win the Nobel Prize.  Now the spotlight is on her

Her work helped her boss win the Nobel Prize. Now the spotlight is on her

For more than 30 years, Donna Elbert wrote numbers for astrophysicist Subrahmanyan Chandrasekhar. Credit: Dianne Hofner Saphiere, Susan Elbert Steele, Joanne Elbert Kantner

Scientists have long studied the work of Subrahmanyan Chandrasekhar, the Indian-American astrophysicist who won the Nobel Prize in 1983, but few know that his research into stellar and planetary dynamics owes a deep debt of gratitude to an almost forgotten woman : Donna DeEtte Elbert.

From 1948 to 1979, Elbert worked as a “calculator” for Chandrasekhar, tirelessly creating and solving mathematical equations by hand. Although she shared authorship with the Nobel laureate on 18 papers and Chandrasekhar enthusiastically acknowledged her seminal contributions, her greatest achievement remained unrecognized until a UCLA postdoctoral researcher connected threads in Chandrasekhar’s work, which they took back to Elbert.

Elbert’s achievement? Before anyone else, she predicted the conditions claimed to be optimal for a planet or star to generate its own magnetic field, said the scientist, Susanne Horn, who spent half a decade building on Elbert’s work.

Now, Horn and UCLA professor of Earth, planetary and space sciences Jonathan Aurnou have published a paper in Proceedings of the Royal Society A in which they present the newly named “Elbert range,” detailing their predictions about the range of combinations that rotation, convection, and magnetism can assume best generate a planet-wide magnetic field.

The work, the authors say, will help researchers from a variety of disciplines better understand conditions inside Earth and inside other planets, and identify planets outside our solar system with the potential to host life.

“Elbert didn’t have a formal math degree, but what she was doing, most people couldn’t do these days. It’s very hard math, usually done using modern electronic computers,” said Horn, now an associate professor at the Center of Fluid and Complex Systems Research from Coventry University in the UK. “Chadrasekhar says in the footnotes that the subtle and elegant ways to solve certain problems were actually proposed by Elbert. She is everywhere in his treatise on geophysical and astrophysical fluid dynamics, but is not an author. Today, she would be considered a mathematician in her own right. right, but in the ’50s and ’60s, it was hard for a woman to get more credit than a footnote.”

And because Elbert’s discovery of the generation of planetary magnetic fields remained embedded in her employer’s body of work, the discovery was generally attributed to Chandrasekhar, who shared the Nobel Prize in Physics for discoveries related to stellar evolution and massive stars.

Horn said she hopes the work she and Aurnou have undertaken to refine and expand on Elbert’s original predictions provides a fitting — if belated — tribute to Elbert, who died in 2019 at age 90 .

The Elbert Range: How Planets and Stars Create Magnetic Fields

Planets generate their own magnetic fields through the internal circulation of heated, electrically conducting fluids such as liquid metals or highly salty oceans. As a planet rotates on its axis, the movement of these fluids becomes organized, generating planetary magnetic fields along the way. Scientists believe that planets with magnetic fields are more likely to support life because the magnetic field acts as a kind of cocoon that protects the planet from the often hostile surrounding space environment, Aurnou said.

“The key is that you have all these fluid motions. The Earth’s core is predominantly composed of liquid iron. As the planet slowly cools in space, the cooler top of the liquid core sinks and the hotter iron rises to depth.” , he explained.

The movement caused by this sinking and rising is known as convection. Convection movements in electrically conductive materials, such as liquid iron in the Earth’s core, can create electrical currents that can then generate a planet’s global magnetic field.

“It’s not clear whether convective turbulence alone will generate a planetary-scale magnetic field,” Aurnou noted, “but we know that planetary rotation organizes turbulence into motion patterns that can.” In other words, he said, rotational forces called Coriolis forces move fluids in predictable ways as the planet rotates. “Elbert was the first to point out that when these rotational forces are comparable in strength to magnetic forces, then convection will begin to organize on the scale of the planet itself. It’s such a simple and responsive system.”

Elbert discovered this principle for himself while Chandrasekhar was on a summer lecture tour and presented it to him upon his return. He incorporated Elbert’s discovery into his own paper and credited it in a footnote without elaborating further on its significance.

But Horn jumped at Elbert’s work.

“What we did was to look for how the convection patterns in liquid metals and their evolution vary when they are subjected to both rotation and magnetic fields,” Horn said. “We discovered that there are different regimes of convective behavior and we determined exactly where these regimes are. This work makes a whole suite of new predictions that we will use to build future laboratory and numerical models of planetary and stellar magnetic field generation. “

The open access paper, “The Elbert range of magnetostrophic convection. I. Linear theory,” is the first in a series of three papers Horn and Aurnou plan to publish that build on Elbert’s work.

Strong planetary magnetic fields like Earth’s can protect oceans from stellar storms

More information:
Susanne Horn et al., The Elbert Range of Magnetostrophic Convection. I. Linear theory, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences (2022). DOI: 10.1098/rspa.2022.0313

Provided by University of California, Los Angeles

Citation: Her work helped her boss win the Nobel Prize. Now the spotlight is on her (2022, September 15) Retrieved September 20, 2022, from https://phys.org/news/2022-09-boss-nobel-prize-spotlight.html

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