{"id":172863,"date":"2023-06-27T14:12:32","date_gmt":"2023-06-27T12:12:32","guid":{"rendered":"https:\/\/us.edu.pl\/?p=172863"},"modified":"2023-07-03T09:25:35","modified_gmt":"2023-07-03T07:25:35","slug":"cebulowa-madonna-fizyki-maria-goeppert-mayer","status":"publish","type":"post","link":"https:\/\/us.edu.pl\/en\/cebulowa-madonna-fizyki-maria-goeppert-mayer\/","title":{"rendered":"The Onion Madonna of Physics \u2013 Maria Goeppert-Mayer"},"content":{"rendered":"

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\"Portret<\/p>\n

Maria Goeppert-Mayer\u2019s portrait | public domain, Wikimedia Commons<\/span><\/p>\n

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| Weronika Cygan |<\/span><\/p>\n

She was awarded the Nobel Prize in Physics in 1963 for proposing the nuclear shell model of the atomic nucleus. That\u2019s why she was given the nickname \u201cOnion Madonna\u201d.<\/strong><\/p>\n

Thanks to her origin from a family of intellectuals, she had an education that few women had access to at the time she lived. Despite this, her educational path was not easy..<\/p>\n

\u201cOther women researchers of those times also came from an environment where the education of girls was valued. Maria Goeppert-Mayer’s father was a sixth generation professor. Mother \u2013 a French teacher \u2013 also grew up in a family that valued education\u201d says El\u017cbieta Stephan, PhD, DSc, Assoc. Prof. from the Faculty of Science and Technology of the University of Silesia in Katowice.<\/p>\n

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A rough start<\/strong><\/h3>\n

The Nobel Prize winner, born on 28 June 1906 in Katowice, moved with her parents to G\u00f6ttingen quite quickly. As a four-year-old, she soaked up the academic atmosphere \u2013 her father got a job at the local university. She finished school and then began studying mathematics. However, after three years she switched to quantum physics. Back then, the University of G\u00f6ttingen enjoyed a unique reputation as a research centre in this rapidly expanding field. The supervisor of her doctoral thesis defended in 1930 was Max Born himself.<\/p>\n

Shortly after graduating, Maria Goeppert-Mayer went to the United States, the homeland of her husband, chemist Joseph Edward Mayer.<\/p>\n

\u201cShe left with the hope that she would have better chances for development and a scientific career there. Unfortunately, she was very disappointed, because the rules at American universities forbade the employment of spouses. The beginning of her career was a relay race of volunteers and various commissioned works. Nevertheless, she was constantly trying to stay in touch with the scientific community\u201d explains Prof. El\u017cbieta Stephan.<\/p>\n

A breakthrough in the career of the future Nobel laureate was her inclusion in the work on the project of American atomic weapons in the Manhattan programme. After the war, she was finally formally employed for the first time. Thanks to this, she was able to undertake research that eventually led her to the Nobel Prize in Physics.<\/p>\n

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\"Maria<\/p>\n

Maria Goeppert-Mayer during the Nobel Prize ceremony (with King Gustaf Adolf) | public domain, Wikimedia Commons<\/span><\/p>\n

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Magic numbers<\/strong><\/h3>\n

\u201cFor discoveries related to the shell model of atomic nuclei\u201d \u2013 this was the justification of the Nobel Committee, awarding Maria Goeppert-Mayer and J. Hans D. Jensen a medal for their parallel work on the same issue.<\/p>\n

\u201cIn order to understand the importance of the discovery, one has to realise what stage of development nuclear physics was at the times when Maria Goeppert-Mayer started her research\u201d says the physicist from the University of Silesia. At that time, the composition of the atomic nucleus composed of nucleons (protons and neutrons) was already known, and the nature of the nuclear force was quite well versed. Many nuclei and their properties such as mass, charge and binding energy were known. However, there was still not enough knowledge on how the nucleus of an atom is constructed. Several puzzle pieces were missing or didn’t fit together in the previous concepts. Maria managed to find the necessary pieces of the puzzle.<\/p>\n

The secret was in hidden in shells and magic numbers \u2013 the properties of strongly bound atomic nuclei with a certain number of protons or neutrons. For a long time, the regularity of these numbers remained misunderstood. Only the shell model described by the Nobel Prize winner explained the meaning of magic numbers and allowed us to understand how they translate into the properties of nuclei.<\/p>\n

It is worth noting that the shells described by Maria Goeppert-Mayer should not be confused with the electron shells around the nucleus. The latter are much larger in size and their filling with electrons determines the chemical properties of atoms. Nuclear shells make up the nucleus itself \u2013 if the size of an atom were compared to a football stadium, the nucleus would be about the size of an onion. In both cases, the ordering is derived from the Pauli exclusion principle, which prohibits two particles (electrons, protons, neutrons) from occupying the same state.<\/p>\n

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Onion atomic nucleus<\/strong><\/h3>\n

While, as a matter of simplification, the structure of the atom is sometimes compared to the Solar System – with the central Sun (atomic nucleus) and the surrounding planets (electrons) – in the case of the shell model of the atomic nucleus itself, this comparison would be too far-reaching. The nucleus does not have its \u201cSun\u201d in the centre, because it is made up of equal protons and neutrons.<\/p>\n

\u201cIn order to explain it, Maria Goeppert-Mayer introduced a comparison to an onion. You probably associate such an analogy with the movie \u201cShrek\u201d, where it is said that ogres are like onions, because they are made of layers. It can also be applied to the atomic nucleus, which is made of shells filled separately by protons and neutrons. The quantum-mechanical description of this model required knowledge of both mathematics and quantum physics, so the preparation of the Nobel Prize winner during her studies and her skills in this field were of key importance\u201d explains Prof. El\u017cbieta Stephan.<\/p>\n

In addition, in the course of her work, the Nobel Prize winner noticed that the values of magic numbers predicted by the shell model did not agree with the data obtained as a result of experiments. This second major discovery ultimately led her to understand the structure of the atomic nucleus.<\/p>\n

In her model of the atomic nucleus, Maria Goeppert-Mayer additionally introduced the concept of coupling of the nucleon’s spin with its orbital motion on a given shell. \u201cThis allowed the magic numbers to be recreated and ultimately contributed to the success of the shell model. It was an absolute breakthrough. From that moment on, nuclear physics knew what it was and how the object it dealt with worked. It was possible to predict the properties of nuclei based on the number of nucleons of a certain type\u201d sums up the expert from the University of Silesia.<\/p>\n

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\"Mural<\/p>\n

A mural of Maria Goeppert-Mayer on the wall of the Rectorate of the University of Silesia | photo: Weronika Cygan<\/span><\/p>\n

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A living legacy<\/strong><\/h3>\n

The shell model of the nucleus proposed by the scientist from Katowice is still valid in physics and is constantly developed by successive generations of scientists. Another milestone in this history was the Nobel Prize awarded in 1975, this time for supplementing Maria Goeppert-Mayer’s concept with a new quality. Three physicists received the award: Aage Niels Bohr, Benjamin Mottelson and James Rainwater. They took into account the existence of deformed nuclei and drew attention to the so-called collective motions, when certain nucleons become activated, causing the surface of the nucleus to vibrate. The collective model complemented the shell model by better description of the properties of large nuclei far from the \u201cmagic numbers\u201d.<\/p>\n

The concept developed over 70 years ago (proposed in the journal Physical Review 78 from 1950) by the researcher born in Katowice still allows for the creation of new physical theories. New magic numbers and heavy atomic nuclei are constantly being sought.<\/p>\n

\u201cPhysicists expect that there is still some island of stability and around the next magic number some nuclei are grouped, which will live not only for microseconds, seconds or minutes, but for years. The discovery of such nuclei would be a beautiful culmination of the shell model\u201d says Prof. El\u017cbieta Stephan.<\/p>\n

Maria Goeppert-Mayer was also active outside of her studies, actively participating in the social sphere. She has strongly expressed her opposition to nuclear proliferation. She died less than ten years after receiving the Nobel medal as a result of a heart attack.<\/p>\n

In 2023, it will be 60 years since the Nobel Prize was awarded to the physicist.<\/p>\n

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Sources<\/h3>\n