40 Fun Facts About Sophie Germain

Which male pseudonym did Sophie Germain use to send her work to mathematicians who might dismiss a woman?

Monsieur Le Blanc was a real former student in Paris whose name she borrowed, fearing what she later called the ridicule attached to a female scientist.

How did Sophie Germain's parents try to stop their teenage daughter from studying mathematics at night?

Her parents removed her fire and clothes at night, hoping the cold would keep her in bed. She wrapped herself in quilts, lit hidden candles and carried on with her sums anyway.

Which German mathematician did Sophie Germain ask a French general to protect when troops occupied his home town?

Carl Friedrich Gauss was baffled when an officer asked after him on behalf of a Mademoiselle Germain: he knew his pen friend only by a man's name, and her confession soon followed.

Which Paris landmark was built bearing the names of 72 French men of science, but not Sophie Germain's?

The Eiffel Tower was built with 72 names in raised letters beneath its first balcony, all of them men, although Germain's own mathematics fed into the engineering of the tower itself.

Sophie Germain took up mathematics after reading how which ancient thinker was killed while absorbed in geometry?

Archimedes, the story goes, was cut down by a Roman soldier because he would not leave his diagram. The 13-year-old Germain decided that a subject so gripping deserved her whole attention.

Which ruler, impressed by a demonstration of sound made visible on metal plates, set the prize Sophie Germain later won?

Napoleon watched a German physicist make metal plates sing in Paris and set a prize for explaining the patterns. For years Germain was the only person who dared to enter.

Sophie Germain made early progress on which famous problem, finally solved in the 1990s after centuries of effort?

Fermat's Last Theorem beat everyone from 1637 until Andrew Wiles in 1994. Germain's plan was the first to attack whole families of exponents at once instead of one number at a time.

The Academy prize that Sophie Germain finally won in 1816 was a medal containing a kilogram of which metal?

Gold, a full kilogram of it, rewarded her final entry in a contest so daunting that almost nobody else in France would attempt it.

The crater Germain, some 35 kilometres wide and named after Sophie Germain, lies on which world?

Venus has a naming rule that every crater honours a famous woman or carries a female first name, so the crater Germain keeps exclusively female company in the southern hemisphere.

What did Sophie Germain do on the day the Paris Academy of Sciences awarded her its grand prize in 1816?

She skipped the ceremony, to the disappointment of a public that had turned out to see the first woman ever to win a prize from the Academy.

Which Paris landmark fell when Sophie Germain was 13, leaving her shut indoors with her father's books?

The Bastille fell when she was 13, and with unrest in the streets she was kept at home, where a history of mathematics on her father's shelves changed the course of her life.

Which two languages did the teenage Sophie Germain teach herself so that she could read Newton and Euler?

Latin and Greek were the languages of much classic science, so she taught herself both from her father's library before moving on to advanced texts on calculus.

Which illness did Sophie Germain work through for two years, still writing papers, before it killed her in 1831?

Breast cancer was diagnosed in 1829, and despite the pain she finished papers on number theory and on the curvature of surfaces that appeared in print the year she died.

Which actress plays Catherine, who discusses Sophie Germain with a fellow mathematician, in the 2005 film Proof?

Gwyneth Paltrow had already played Catherine on the London stage before the film, in which her character talks about Germain and her special primes with a student played by Jake Gyllenhaal.

Sophie Germain was born in Paris in the same year that which country declared its independence?

United States independence was declared in July 1776, three months after Germain's birth on 1 April, and she was a teenager when revolution reached her own country.

Sophie Germain was a pioneer of which branch of physics, later vital to engineering great iron and steel structures?

Elasticity is the study of how solids deform and spring back, and Germain's prize essay reached the correct differential equation for a thin plate despite her patchy training.

In the experiments behind Sophie Germain's prize essay, what was sprinkled on a metal plate to reveal patterns of sound?

Sand skips away from the parts of a bowed plate that shake and gathers along the lines that stay still, drawing stars and grids that Germain set out to predict with an equation.

Which Paris school, opened in 1794, barred Sophie Germain as a woman yet let outsiders request its lecture notes?

École Polytechnique made its lecture notes available to anyone who asked, so Germain followed its courses from home. The school did not admit its first women students until 1972.

Which professor asked to meet a gifted student who sent him written work, only to find it was Sophie Germain?

Joseph-Louis Lagrange did not mind in the least that his star correspondent was a young woman: he became her mentor and friend and made his colleagues aware of her talent.

A prime number p counts as a Sophie Germain prime when which related number is prime as well?

2p + 1 must be prime too, so 11 qualifies because 23 is prime, while 7 fails because 15 is not. Germain met such primes while attacking a famous unsolved equation.

In cryptography, which word describes the larger prime that is paired with each Sophie Germain prime?

Safe primes are prized in public-key cryptography: key exchanges such as Diffie–Hellman rely on them, which gives Germain's idea from the early 1800s a daily job in online security.

Sophie Germain's death certificate ignored her mathematics and recorded her occupation as what?

A property holder, rentière in French, is all the official wrote: a woman living on private income, with no hint of the prize-winning scientist she had been.

By most accounts, what was the trade of Sophie Germain's father, Ambroise-François, in eighteenth-century Paris?

Silk merchant is the usual answer, though some accounts make him a goldsmith first. His well-stocked library is where his daughter discovered mathematics.

Sophie Germain never received the honorary degree that an admirer wanted for her from which German university?

Göttingen never gave her the degree. A professor there, her old German correspondent, said she had shown that a woman could excel in the most rigorous of the sciences and deserved one.

Which first name did Sophie Germain share with her mother and her elder sister, perhaps explaining why she used Sophie?

Marie began all three names: her mother and elder sister were both Marie-Madeline and she was Marie-Sophie, so going by Sophie may simply have kept the household straight.

Which relative of Sophie Germain collected her philosophical writings and had them published after she died?

Her nephew Armand-Jacques Lherbette, her elder sister's son, gathered the essays, including one arguing that the sciences and the humanities do not differ in substance.

In the revolutionary year of 1789, Sophie Germain's father was elected a deputy for Paris representing which group?

The Third Estate, the commoners, soon turned itself into the National Assembly, so talk of politics and philosophy probably filled the Germain home while Sophie was growing up.

What did Sophie Germain's second, anonymous entry for the Academy's prize contest earn from the judges in 1813?

An honourable mention was all the judges would give: the entry was littered with errors and, they said, the fundamental base of her theory was still not established.

How did Sophie Germain's prize-winning essay finally appear in print in 1821, five years after it won?

At her own expense she had it printed, chiefly so that she could set her theory against a rival's and point out the errors in his method.

Sophie Germain's grave lies in which Paris cemetery, the largest within the city?

Père Lachaise holds her gravestone, and a plaque marks the house on the rue de Savoie where she died; the honours came only after a biography revived her name in the 1870s.

Which science-fiction author co-wrote, with Frederik Pohl, a 2008 novel whose hero is inspired by Sophie Germain?

Arthur C. Clarke and his co-author credit Germain with inspiring their central character, Ranjit Subramanian, to take on a proof that had beaten mathematicians for centuries.

Which French philosopher, the founder of positivism, highly praised Sophie Germain's essay on the sciences and letters?

Auguste Comte was the admirer, and a later German historian of philosophy judged that the essentials of positivism were already present, unnamed, in Germain's own writing.

Which Academy secretary, a veteran of France's expedition to Egypt, got Sophie Germain tickets to attend its sessions?

Joseph Fourier befriended her after her prize, and his tickets finally let her into meetings that the Academy otherwise closed to every woman except the wives of members.

Which rival left Sophie Germain alone in the Academy's prize contest when he was elected a member and became a judge?

Denis Poisson went from competitor to judge, read her entries in that role, then published his own theory of the subject in 1814 without acknowledging her help.

Whose 1798 essay on number theory drew Sophie Germain into the field and later credited her best result in print?

Legendre called her work very ingenious, and her most important result is known today only because he explained it in a footnote to his own treatise.

Which German physicist, called the father of acoustics, ran the plate experiments behind Sophie Germain's prize essay?

Ernst Chladni first published his technique in 1787, and the patterns still bear his name; the contest Germain entered asked for the mathematics that would explain them.

Which landmark treatise of 1801 did Sophie Germain study for three years before writing to its young author?

Disquisitiones Arithmeticae renewed her interest in number theory; its author was a year younger than Germain and received her first letter, signed with a man's name, in 1804.

The Germain curvature, a measure Sophie Germain used in studying surfaces, is better known as which kind of curvature?

Mean curvature averages a surface's greatest and least bending at a point, and a surface where it is zero everywhere is called minimal.

The Limit, a 2019 London stage show about the life of Sophie Germain, takes which form?

A musical by Freya Catrin Smith and Jack Williams, The Limit opened at London's VAULT Festival and set the story of a self-taught number theorist to song.

After an 1879 biography revived Sophie Germain's fame, Paris named a street and what kind of institution after her?

A girls' school took her name in 1888 and became the Lycée Sophie Germain; the city placed a bust of her in its main courtyard two years later.