Marietta Blau spent fifteen years developing nuclear photographic emulsions, chemical films capable of recording and measuring the tracks of charged particles from nuclear reactions. She worked with manufacturers Agfa and Ilford to formulate emulsions sensitive enough to distinguish alpha particles from protons and to determine particle energies from track lengths measured under a microscope.
In 1937, she and Hertha Wambacher placed emulsion plates at an altitude of 2,300 metres on Hafelekar Mountain and discovered starbursts of particle tracks radiating from a single point, cosmic ray particles disintegrating heavy nuclei in the emulsion.
They named them Zertrummerungsterne (disintegration stars), and it was their discovery that launched particle physics. When they wrote up the result, her Nazi colleagues pressured her to list Wambacher’s name before hers. Weeks later, the German annexation of Austria forced her out of the country.
Cecil Powell built on her technique, discovered the sub-atomic particle, the pion, and received the Nobel Prize in 1950. His Nobel lecture did not mention her contribution. The theoretical physicist Erwin Schrödinger nominated her for the Nobel multiple times. She spent her final years in Vienna in an unpaid position, analysing particle track photographs from CERN experiments, unable to afford health insurance. Her death in 1970 went unnoticed by the scientific community. Read more
Marie Skłodowska Curie, more well known than other women in physics and chemistry, developed the radiochemical separation methods that made it possible to isolate individual radioactive elements from complex matrices, fractional crystallisation and precipitation from pitchblende ore. To isolate radium and polonium, she carried out this research in a leaking shed over four years.
The actinide separation chemistry in sample preparation for accelerator mass spectrometry (isolating uranium and plutonium isotopes at concentrations of one atom in a quadrillion) is descended from that historic methodological milestone. Although Marie Skłodowska Curie was awarded two Nobel Prizes, in Physics and Chemistry, the French Academy of Sciences still refused to admit her as a member. Read more
Rosalind Franklin developed the X-ray diffraction techniques that produced the experimental evidence for the double helix structure of DNA. Working at King’s College London, she optimised humidity-controlled fibre preparation and long-exposure crystallography to obtain diffraction patterns of sufficient resolution to draw structural conclusions. Photograph 51, taken under her direction by Ray Gosling in 1952, showed the characteristic X-shaped diffraction pattern of B-form DNA. By early 1953 she had drafted papers concluding that both forms of DNA contained two helices.
Watson and Crick saw Photograph 51 without her knowledge, shown to them by her colleague Maurice Wilkins. Their double helix paper appeared in Nature in April 1953. Franklin’s name was not on it. In 1962, Watson, Crick, and Wilkins received the Nobel Prize in Physiology or Medicine. Franklin had died of ovarian cancer in 1958, at thirty-seven. Nobel Prizes are not awarded posthumously.
Her earlier work, less discussed, directly underpins materials characterisation methods used across ANSTO: she spent three years at the British Coal Utilisation Research Association developing X-ray diffraction analysis of carbon microstructure, work that established the distinction between graphitising and non-graphitising carbons and shaped the field of carbon science. Read more
Maria Goeppert Mayer worked out why nuclei with 2, 8, 20, 28, 50, 82, or 126 protons or neutrons are exceptionally stable. She showed that these magic numbers reflect nucleons occupying discrete shells with strong spin-orbit coupling, in which a nucleon’s orbital angular momentum and intrinsic spin interact to produce the observed stability pattern.
For years she carried out this work as an unpaid volunteer, barred from salaried positions by anti-nepotism rules because her husband held faculty appointments at the same institutions. She received her first paid professorship in 1960 and won the Nobel Prize in Physics in 1963, the second woman to do so, fifty years after Curie. Read more
Lise Meitner fled Berlin in 1938, smuggled across the Dutch border by colleagues, after the Nazis’ annexation of Austria, the Anschluss, stripped her of Austrian protection.
Working from exile in Stockholm, she and her nephew Otto Frisch provided the theoretical explanation for what Hahn had observed in their Berlin laboratory, that the uranium nucleus, bombarded with neutrons, splits into two smaller nuclei and releases an enormous quantity of energy.
She calculated the amount of energy released using Einstein’s mass-energy equivalence, and she coined the word fission. Hahn published without her name. In 1944 he received the Nobel Prize for the discovery.
Meitner was nominated forty-nine times and never received one. She declined an invitation to join the Manhattan Project, “I will have nothing to do with a bomb.”
Element 109 meitnerium is named after her. Read more
In 1918, Emmy Noether proved that every continuous symmetry of a physical system has a corresponding conservation law, and vice versa. Time-translation symmetry gives conservation of energy. Space-translation symmetry gives conservation of momentum. Rotational symmetry gives conservation of angular momentum.