Tag Archives: physics

Women in Science at the End of the World

It is one thing to use science to better understand the world, another to fear the world itself is crumbling all around you. And yet the scientists who were pursuing research during World War II must have felt both these things keenly, as the Great Powers became embroiled in the second major war in a generation.

Against this backdrop, scientific advances were about to become very
important to the course of the war, and the public perception of science was about to be changed indelibly. Researchers in Europe and the United States were digging to the heart of nuclear fission, an understanding of how the nuclei at the heart of atoms could split, changing into other elements in a naturally-occurring process. Fission was also thought to release an unheard of amount of energy, which in wartime led to one obvious thought: was it possible to use fission to build a bomb?

The Project
After a report from the UK was shared with the US Army, which coordinated the results of a series of secret conferences to discuss the possibility of a fission bomb and how it might be designed, the Army Corps of Engineers launched what was called ‘the Manhattan Project’. Major General Leslie Groves was put in charge, and appointed as scientific director Robert Oppenheimer, an expert in neutron collisions at the University of California Berkeley (the only university with a particle accelerator powerful enough to make plutonium, which had been recently discovered in 1941). Oppenheimer’s first task was to find a suitable location to build a lab where a fission bomb could be designed, built, and eventually tested.

As a child, Oppenheimer suffered from tuberculosis and recovered at the Los Alamos Ranch School in the New Mexico mountains. Far from any major settlements, this location seemed ideal to Oppenheimer and he suggested it as the main site for the Manhattan Project. The land at Los Alamos was purchased by the US government in late 1942, with scientific work beginning there in 1943. Initially General Groves had imagined a military installation, with the scientists in uniforms and posted away from their families. But key scientists balked at uniforms and many wished to bring their families with them. The Los Alamos scientists, working in secret, are often considered a boys’ club, plus wives. Yet even in wartime, and facing prejudice their male counterparts did not, women made huge scientific contributions to the success of the Manhattan Project.

Lise Meitner


The physicist whose work set the scene for the development of the fission bomb, though she would not have wished it, was Austrian-born Lise Meitner. Working in pre-war Germany, she and long-time collaborator Otto Hahn developed the theory and the experimental understanding of nuclear fission. But Meitner was uprooted from Germany due to the Nuremberg laws and her Jewish heritage, and she was forced to flee to Stockholm to continue her work. Her German-based colleagues left her name off several key papers, fearing repercussions from the Nazi authorities. And so the Nobel Prize for Physics in 1944 was then awarded to Meitner’s main collaborator, Otto Hahn, for the discovery of nuclear fission. Although the Nobel committee later revealed that the complications of wartime and the difficulty of assessing interdisciplinary work had contributed to Meitner’s omission from the prize, the US Army had recognized her contribution and invited her to join the Manhattan Project. Her experimental and theoretical insight had clearly been critical, and she was no longer ensnared in Nazi Germany as Hahn was. But Meitner refused to join the Project, saying ‘I will
have nothing to do with a bomb!’ Her advancement of the theory of nuclear fission was, nevertheless, critical to the Project’s success.

Lilli Hornig


Among the women who did join the Project was Lilli Hornig, a Czech chemist who specialized in the newly discovered element plutonium. She had a master’s degree from Harvard when the Manhattan Project began and came to Los Alamos married to an explosives scientist, having been told that anyone
with a chemistry background would be welcomed on board.

Upon arrival, however, Horning was offered a typing job, and was only permitted to work on plutonium chemistry after saying she did not know how to type. Hornig was moved to the explosives group once lab management realised the intense radioactivity of plutonium might cause reproductive damage. ‘I tried delicately to point out that they might be more susceptible than I was; that didn’t
go over well,’ she said in an interview with Manhattan Project Voices (a public
archive of oral histories).

Hornig was eventually a witness to the ‘Trinity’ test of the first so-called ‘atomic
bomb’ in Alamogordo, New Mexico. The Trinity detonation used plutonium as its fissile material, standing on the shoulders of Hornig’s work, but after seeing the devastation it was capable of, she signed a letter along with 100 other scientists requesting that the bomb be demonstrated to the Japanese on an uninhabited island. The next two nuclear detonations occurred over the cities of Hiroshima and Nagasaki, killing over 100,000 people. After the war had ended, Hornig went back to graduate school, getting her PhD and becoming a chemistry professor at Brown University. She was a feminist and a passionate advocate for women in science, studying inequality in the sciences alongside her first love of chemistry.

Maria Goeppert Mayer


Maria Goeppert Mayer was a German physicist, whose doctoral thesis was super-
vised by Max Born, the father of quantum mechanics. Goeppert Mayer came to America when her husband took employment as a professor at Johns Hopkins, but nepotism laws at the time prevented the wife of a professor from being employed at the same institution. Initially she worked unpaid, collaborating with others and eventually studying the separation of different atomic isotopes. The couple then moved to Columbia University and there Goeppert Mayer began her work with the Manhattan Project, studying isotope separation of uranium compounds to be purified into fissile fuel.

While comparing different isotopes, she began to notice ‘magic numbers’ of nucleons which led to more stable atomic nuclei. In 1945, she went to Los Alamos to work directly with Edward Teller on the successor to the atomic bomb: the hydrogen bomb, which exploited the energy from the atomic fusion of elements.

After the war, Goeppert Mayer continued to develop her shell model of the atomic nucleus, which she likened to pairs of waltzers at a dance: each nucleon was a waltzer paired with another waltzer, and more waltzing couples could be fitted into the nucleus by having some go clockwise, some anticlockwise, paralleling nuclear spin. She finally achieved her first full-time paid position as a scientist in 1960 at the University of California San Diego, after receiving her PhD in 1930. When she received the Nobel Prize in Physics in 1963, for her shell model of the atomic nucleus, the local newspaper headline read ‘S. D. mother wins Nobel Prize’. Goeppert Mayer was the second female Nobel Laureate in physics, after Marie Curie.

Each of these women had critical scientific and technical contributions to the Manhattan project, but the politics of the time and secrecy surrounding the wartime effort shrouded the impact of their work. The contributions of male scientists to the Project are more widely touted, and although Hornig, Goeppert Mayer, and Meitner are long gone, the scientific establishment today still struggles to appropriately acknowledge the contributions of women.

Furthermore, that a Czech, a German, and an Austrian were so central to ending an international war, displaced from their countries of origin, shows the value of immigration and even of wartime refugees. Despite difficulties accessing academia and key resources, female scientists played a major role in the Manhattan Project, the building of the first atomic bomb, and the end of World War II.

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What Is Life? And Other Interdisciplinary Questions

Scientists, like most people, want to understand the world they live in. We examine the physical structure of the world, in the hope that understanding the rules governing it will also lend some clue as to what it all means. Ironically, as the boundaries of scientific knowledge grow, the possibility of any individual scientist grasping this entire meaning gets smaller and smaller. Even within science, the traditional disciplinary boundaries—biology, chemistry, physics—often separate scientists who should really be talking to each other. I have always loved talking to people who know different things than I do, prompted by curiosity and encouraged by family. But it can be rare to see famous scientists doing the same.

Erwin Schrödinger, a physicist famous for his mathematical and philosophical development of quantum mechanics, tried to reach across these boundaries and ask the question that compels so many of us, namely ‘What Is Life?’ His historic lectures were given in 1943, against the backdrop of world war and 75 years behind our current understanding of biology. And in a wise move for anyone trying to understand something new, Schrödinger began by admitting what he didn’t know: to him, the difference between what physics and biology had to say about life was the difference between “a wallpaper and a Raphael tapestry”.

And yet, connecting physical understanding to biology has provided significant insights. When these lectures were given, the DNA molecule itself had already been discovered, but the double helix structure was yet to be found, along with much of our modern understanding of how this blueprint for life works. And yet the stability of the DNA molecule in the cell is directly due to the quantum basis of chemical bonds. Schrödinger expresses amazement that even with the perturbations caused by heat and environment at the molecular level, the naive physicist’s expectation of wild variability is incorrect, and chemical stability holds. While DNA does sometimes mutate in ways that persist through generations, forming the basis of natural selection, its ability to reproduce error free throughout our lives is amazing from a physics perspective. Especially when one considers the consequences of uncontrolled mutation, as the world would see only two years later as radiation-induced mutation caused terrible illness in the survivors of Hiroshima and Nagasaki.

In trying to define life, Schrödinger comes to the idea of order and disorder, and the physicist’s idea of entropy. Although entropy, which is a measure of disorder, is bound to increase over time subject to the Second Law of Thermodynamics, Schrodinger posited that living beings were effectively decreasing their local entropy by exporting it, increasing order within the cell even if the broader environment became less ordered. Cheating the Second Law of Thermodynamics is a necessity for living cells, living beings, and even our planet to maintain local order. Schrodinger then concludes that living beings must be ‘negative entropy machines’, converting energy to local order, a perspective only a physicist could have come up with.

Schrödinger’s willingness to admit what he did not know, and try to combine modern biology and modern physics even during wartime to unify humanity in knowledge, put me in mind of another, less famous, transdisciplinary scientist.

A man pipetting.

My father, Eric Fairfield, was a biochemistry professor who left academia to work on the Human Genome Project. We talked about science a lot, especially once I chose to pursue physics. I know he was proud of me for becoming a scientist, even though as a biochemist he could not resist ribbing me for my limited understanding of biology. When I read Schrodinger’s statement:

THE CLASSICAL PHYSICIST’S EXPECTATION, FAR FROM BEING TRIVIAL, IS WRONG

I could nearly hear it in my dad’s voice. The “naive physicist’s approach” to understand the cell by looking to statistical physics and randomnessi misses the stability of chemical bonds in the DNA molecule and other cellular components. In a messy, changeable environment, the blueprints that make us have persisted through thousands of generations. As my dad used to say, biology had this figured out a long time before we even knew what questions to ask.

But this isn’t to say that physicists have no business asking questions in biology, or vice versa. Biology is built on the laws of physics and chemistry, even if the exact details of how are still being puzzled out today. And questions that my dad put to me, as part of his own research, often had me questioning both physics and biology. How does a cell know what organ to build a piece of? What biochemical signals lead to the evolution of our own sensory organs, like ears or eyes? How does higher level order arise from molecule level decisions?

I enjoyed discussing these questions with him, and asking my own about the chemistry of the nanomaterials I studied, and their current and possible future biological applications. But the last big biological questions my dad asked ended up being about cancer, a scientific issue that has absorbed the careers of many researchers. Colon cancer took my father’s life last year, and when I have a question about biology, I can no longer call him to see if he’s thought about it before. At his memorial service, many friends commented how much they enjoyed talking science with my dad, whether they had a scientific background or not. He enjoyed discussing and debating these topics with anyone, even if and sometimes especially if they had a vastly different perspective to his own. But I think science would get a little bit further if we had more scientists like my father, or like Erwin Schrödinger, who were willing to cross disciplinary boundaries, admit what they don’t know, and see where they can go from here.

My scientific colleagues may find this to be a very personal response to a scientific matter. But Schrödinger himself dedicated What Is Life? to the memory of his parents. We are all searching for answers together, inspired by those who have come before, and certain to be surprised by what comes next.

When Your Science Hero is Problematic

We all have heroes, people we look up to and whose achievements spur us on to do our own personal best. And, especially in this era where women are saying #metoo and finally being heard, we have probably all had the experience of finding out that one of our heroes has done some less than heroic things. This has come up a lot for me recently with the deaths of some very famous scientists and science fiction writers, men I greatly admired when I was a kid, who I’m now discovering were frequently awful to women (i.e., people like me).

I think this happens more than usual in science, a traditionally male-dominated field where a culture of elitism and privilege has been embedded for a long time. And it’s tempting to view things in black and white: either my hero is amazing for their achievements or they are garbage for their behaviour. We know in our personal lives that people are multi-faceted, yet we’re slow to allow public figures that same understanding. If a famous male scientist discovers lots of things, and is a great collaborator with other men but acts differently toward women, consciously or unconsciously, how are we meant to think about that?

As a physicist who loves to write, I’ve had to consider this before, because one of my early science heroes was Richard Feynman. Feynman was a brilliant theoretical physicist, a Nobel laureate, and worked on the Manhattan project building the atomic bomb in my hometown of Los Alamos. He also wrote a series of very enjoyable popular science books, which were also quite personal and effortlessly engaging. A quote from an interview that immediately stuck with me:

Omni: As we came back to the office, you stopped to discuss a lecture on color vision you’ll be giving. That’s pretty far from fundamental physics, isn’t it? Wouldn’t a physiologist say you were ‘poaching’?

Feynman: Physiology? It has to be physiology? Look, give me a little time and I’ll give a lecture on anything in physiology. I’d be delighted to study it and find out all about it, because I can guarantee you it would be very interesting. I don’t know anything, but I do know that everything is interesting if you go into it deeply enough.

As someone who is omnivorous about knowledge, I found that quote resonated with me deeply. Science is fascinating because it shows us how the world works, how things which might appear separate are deeply connected, and the overlapping intricacies behind the everyday we take for granted. I now do my research on nanoscience, a strongly interdisciplinary field that draws from chemistry, electrical engineering, materials science, and plenty more beyond the physics that I got my degrees in. I admired Feynman for not letting other people dictate the questions he could ask, for being a physicist in what felt like a subversive and wide-ranging way. He was also famous for his sense of humour, his love of non-scientific things like playing bongos, and for generally not being as formal and rigid about anything as physicists tend to be.

The author having a Feynman bongo moment at the No-Ball Prizes. Photo by Ian Bowkett.

Of course, if you read Feynman’s books you’ll also find less inspiring stories, if you are a female scientist. He writes about doing his calculations in a Hooters, negging women in bars, and pretending to be an undergraduate to pick up grad students’ wives. This is less subversive, and more what we might generously call ‘of a time’. Feynman did plenty to promote the status of women in physics, encouraging his own sister to study it and eventually get a PhD. But reading through these differing accounts of his behaviour, female physicists are left wondering whether this great man of science would have seen them as colleagues and equals, or as prey.

I still find a lot in Feynman to look up to, as a physicist who did amazing work but cared about communication and didn’t give in to pressure to conform. However I can still acknowledge the women he mistreated, or perhaps even drove out of the field which is a terrible loss to science. He had a complexity to him, and my initial hero-worship of Feynman when I was younger has been replaced by equally complex feelings, of respect for his scientific and communication work alongside frustration at his mistreatment of women. But there’s no such thing as a perfect hero anyway, and if I needed one in physics, I might be waiting a long time. We have many historical women in physics to look up to, like Lise Meitner or Emmy Noether, and yet often these women were denied resources and opportunities that their male colleagues had, which can make them feel like amazing but also tragic figures. I would hope that women working in science today can be heroic without the tragedy.

Perhaps looking for heroes in science is a fundamentally flawed endeavor. Science is at its heart collaborative, and the sheer scope of human knowledge means that it is impossible for one person, toiling alone, to conquer it all. We must talk to each other, work together, and build on existing work, as famously stated by Isaac Newton: “If I have seen further it is by standing on the shoulders of giants.” The great man theory is as flawed when it comes to science as it is when it comes to history. We all seek out role models, but we must recognize that they worked with others, seen and unseen, and that science is a societal effort and not the work of a lone genius.

While Feynman is long gone, there are other scientists still living, still contributing, and still behaving badly. It’s important that we not let them off the hook. Feynman lived decades ago, and certainly the standards of behaviour were different then, but today’s harassers and discriminators have no such excuse. If science is truly a collaborative effort, then it loses strength every time a person is pushed out of science by harassment. We can have complicated feelings about prominent scientists of the past, but there are a lot of people working in science today who are doing it right, and can serve as inspirations.

For example, tomorrow is the first ever LGBT STEM day, being celebrated with events around the world. Our Irish LGBT STEM network, House of STEM, has done so much to organise and promote this event, and founder Shaun O’Boyle explains why it’s desperately needed here:

The past is full of problematic yet successful scientists. Yet I’m hopeful that the future will have a broader array of amazing scientists, working together, who are also amazing people.

Innovative Technologies

I work in nanoscience, and a lot of new materials and devices are developed where people ask, what is going to be the application of this? Can this displace an established technology (like silicon computer chips) or create a new market? And I was recently reminded of a great quote in response:

The principal applications of any sufficiently new and innovative technology always have been—and will continue to be—applications created by that technology.

That was said by Herbert Kroemer in his Nobel lecture, and it bears thinking about in many contexts both within science and in the broader world. When you’re doing something new, it may not fit neatly into the established hierarchies of technology, science, or industry. That can be good, and in fact it can be groundbreaking, like a present you didn’t know you wanted! Of course, it’s still important to think about how your work fits into the broader picture as it already is, but I think it’s always good to get a reminder to check your premises, that innovation can create its own new niches.

Sweat The Small Stuff

Let’s talk about science! Literally, here I am talking about science, the quantum world, scientists, and answering audience questions from a kindly bunch at Pint of Science this May in Dublin. There is also a bit of a surprise in the middle.

Flatland and Extra Dimensions

What would life be like if you lived in two dimensions instead of three?

Back when I posted about popular science books for non-scientists, one of the suggestions I got after the fact was Flatland: A Romance of Many Dimensions, the 19th century classic by Edwin A. Abbott. Which is absolutely worth reading, and a great example of what I love in science writing (or science fiction): an idea that makes you change your whole perspective on the world and reimagine it from a different point of view.

The idea behind Flatland is this: what would it be like if the world we inhabited were flat instead of 3D? You can imagine it as living within a piece of paper, or on the surface of a table. The notion of up and down would be meaningless; we’d only have left and right, and front and back. So we’d be moving in two dimensions rather than three, and we’d also perceive everything around us to have only two dimensions. There wouldn’t be any going over a fence, or peeking under a door. If a thing blocked your way, it would block it completely, and everything behind it would be completely invisible. Of course, you wouldn’t be able to pass through things in Flatland, the same way you can’t in the real world. So if a person stopped directly in front of you, you’d have to pass to either side, or not at all.

There’s a lot of social commentary in Flatland as well, satire aimed at Victorian England that comments on gender divisions, class hierarchies, and dogmatism against new ideas. It’s worth a full read for that, though its examination of spatial dimensions is what’s kept it famous.

Life in Flatland may seem like an academic abstraction. But actually, while our world is three-dimensional, there are some things in it which effectively have only two dimensions, especially in the world of nanoscience. The touted wonder material graphene is effectively two-dimensional, because in the third dimension it’s only one atom thick. That means that electrons moving through graphene are effectively in a two-dimensional environment, a Flatland, and can’t use the third dimension to go around each other. More two-dimensional materials are being discovered every day, and taking one dimension of a material to the nanoscale while leaving the others large changes the physical laws in that material significantly!

And what if there were more dimensions to the world? What if instead of three dimensions to space, there were a fourth, or a fifth? In that case, life here in three dimensions would seem like Flatland, without the fourth dimension to move through. Some physicists studying string theory think there may in fact be additional spatial dimensions, but that they must be curled up within the three we know in order to be undetectable.

So the idea of Flatland, a world where there are only two dimensions instead of the usual three, isn’t just a science fiction classic, it’s also a valuable thought experiment that ties into both nanoscience and string theory!

Reynolds’ World

What’s it like for little things like bacteria to move around? How do they swim from place to place?

We know that swimming feels different from walking. Part of it is the feeling of being suspended, where instead of the firm solidity of the earth and the  insubstantial give of air, we have the water on all sides, supporting not just our feet but our legs, arms, and body. But also, it’s a lot harder to move through water! The same quality that makes us feel supported also impedes movement, so that even a very efficient swimmer will be easily outpaced by someone strolling along on dry land.

Scientists have a way to quantify that  difference, using a measure called the Reynolds number. The Reynolds number compares how strong inertial forces are in a fluid, which come from the particle size and the weight of the particles, with the viscosity of the fluid. If a fluid has low inertial forces compared to its viscosity, it has a low Reynolds number, and if it has high viscosity compared to its inertial forces, then its Reynolds number is low. So fluids with a high Reynolds number are easier to move through, and fluids with a low Reynolds number are harder to move through. The pitch of the Trinity pitch drop would have a very low Reynolds number! And fluid flow in high Reynolds number environments tends to have more chaos, vortices and eddies that can arise because of how easy it is to move light things that don’t stick together, like molecules of air.

So it turns out that what strategy you use to move in a low Reynolds number environment is different from what you’d use in a high Reynolds number environment. Of course, we already know that, because if we try to walk or run in water, it doesn’t work very well! Running is a great way to get around when you are moving through thin air with the solid ground beneath you, but humans have developed various modes of swimming for water, that take advantage of our anatomy and account for the different nature of water.

But remember, we are largely made up of water! So what about our moving cells and bacteria, which have to get around in a low Reynolds number environment all the time? And keep in mind that our cells are very small, subject to molecular forces and a lot closer to the size of water molecules than we are. Not surprisingly, there are different forms of swimming that take place in our cells. One of the most common is using a rotating propeller, a little like the blade on a helicopter, to move forward. These structures are called flagella and are common on the surface of various types of cells, to use rotary motion as a way of easily moving through the high Reynolds number environment.

So the next time you are walking around with ease, take a moment to imagine how different it is for everything moving from place to place in and around your cells. It is a whole different world, right inside our own!