A new book about 12 experiments that changed the world sidelines the role of beautiful theory in physics
- Written by Sam Baron, Associate professor, Australian Catholic University
The Matter of Everything tells the history of physics through experiments. Any book about the history of science for a general audience will, of necessity, be something of a distortion. The question is whether the distortion is useful: does it offer a new perspective on the history of physics? While there is much to like about the book, I found it to be largely polemic and unhelpful.
Review: The Matter of Everything: 12 experiments that changed the world – Suzie Sheehy (Bloomsbury)
Here’s what I liked about the book: it is extremely detailed. It takes us through 12 important experiments within physics from roughly the last century and a half.
The experiments range from the study of X-rays and the nature of light in the early 20th century, to the early development of particle accelerators to detect and study subatomic particles throughout the 20th century, culminating in the modern era of Big Science and the use of the Large Hadron Collider to find the Higgs boson. They are described in a manner that is rigorous and accessible.
Rigour and accessibility clearly trade off, at least for a non-technical audience. The book manages this trade off beautifully. Complex experiments are described in a manner that is easily understood.
The role that those experiments play in pushing forward the frontiers of particle physics – the study of an increasingly large array of very small pieces of reality, including those that constitute matter such as electrons, along with the forces that bind them – is also explained well.
It is done so without needing to take the reader through the details of some imposing theories, most notably: the various quantum field theories within the standard model of particle physics.
Author Suzie Sheehy, an Australian physicist with academic roles at Oxford and Melbourne universities, also does an incredible job of explaining the wider implications of the experiments considered. Sheehy is an expert in accelerator physics: the design and implementation of particle accelerators to conduct experiments.
Careful attention is paid to spin-off technologies developed in the course of building particle accelerators, including the development of Magnetic Resonance Imaging (MRIs) as well as the production of radio isotopes for use in medical imaging more generally.
The point is well-made that developing these technologies was not an aim of scientific investigation but an unpredictable by-product. A word of caution underlies much of the discussion of these technologies: industry should be in the service of science, and not the other way around.
I also loved the book’s relish for the ingenuity of the inventor. For each of the 12 experiments described a common story unfolds: there is something we want to test but we just don’t know how to do it.
Scientists must invent new ways of managing electricity, magnetism, and more just so they can carry out their experiments. The world of experimental particle physics feels suddenly familiar: scientists are tinkerers, hammering out new pieces of equipment in much the same way one might invent a new kitchen utensil on the fly with some duct tape and a healthy dose of optimism.
A distorted history
As noted, The Matter of Everything is an inevitable distortion of the history of physics. One of the main distortions lies with the central premise of the book. The 12 experiments chosen are from the realm of particle physics. Whether by design or by accident, the history of 20th century physics is recast as the history of particle physics.
To say that this leaves a lot out, is an understatement. The standard model of particle physics is rivalled, in rigour and experimental confirmation, only by the general theory of relativity.
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Whereas the standard model describes the world of particles and particle interactions, general relativity describes the large-scale structure of the universe and gravity.
In the 20th century, general relativity was both motivated and ultimately confirmed by a fascinating array of experiments, starting from the ingenious interferometer experiments in the early 20th century to the detection of gravity waves in 2015.
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The focus on experiments relating to particle physics not only paints a strange picture of 20th century physics, but it also tends to cast the standard model in a rosy light. For we now know that the standard model is, in some sense, incomplete. The standard model “conflicts” with general relativity. The two theories are in need of replacement.
A more balanced telling of the history of 20th century physics might have included a wider array of experiments. Of course, a single book cannot cover everything. But some remarks on what is being left out should be offered. Otherwise, an idiosyncratic take on the history of 20th century physics quickly turns into a polemic retelling of where the “real” physics lies.
Experiment and theory
Why experiments? This is a question I kept asking myself throughout the book. Ultimately, the answer appears to be a political one. The book works hard to impress upon the reader the importance of experimental physics. Experiments are where the action is in science. Progress can only be made through gathering empirical data.
This focus on the experimenter as the pioneer, forging a path into new scientific terrain, is at best, a half truth. Companion to the experimenter is the theoretician. Theoretical work and experimental work generally go hand-in-hand. Theoretical physics, however, seems to be downplayed throughout the book.
This is perplexing, given that theories are essential to experimental work twice-over.
Trajectories in a Cloud Chamber.
Image from Gordon Fraser/CERN, http://cerncourier.com/cws/article/cern/28742), CC BY
First, theories are typically needed to generate hypotheses for experimental testing. Much experimental work tests the predictions of known theories in order to confirm them. There are, of course, cases in which an experiment is conducted and produces results that challenge all known theories. But even then, it is the interplay between theory and experiment that drives science forward.
Second, theories are needed to make sense of empirical data. A theory of some kind is typically needed to understand how a given experiment works.
The Large Hadron Collider – a massive ring of electromagnets used to accelerate particles to high velocities before smashing them together, to see what they’re made of – is a case in point. The experiment is so complex that understanding it requires grasping an array of theories from different areas of science. Experimental data in a vacuum is virtually meaningless. Theories provide context for experimental data.
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The suppression of theoretical work in physics is part of the book’s gimmick. But, again, the picture this conveys of 20th century physics is unrealistic. The story of 20th century physics is as much one of beautiful theory, as it is of ingenious experiment. Again, it is hard not to see the focus on experiment as something of a normative statement on how science ought to be done.
Lost voices
People play a large role in the Matter of Everything. Glorious experimental machinery is set against the backdrop of scientist-inventors who tinker and toil. This focus on people is welcome. It helps to humanise the story of 20th century physics, and give the reader a sense that they too could contribute to science, if only they mucked around in the shed long enough.
That being said, the book might have said more about scientists who are widely acknowledged to have been unjustly neglected in the history of their field. As the book itself acknowledges, there is, for example, a need to tell the story of women scientists.
Given this, I found the omission of Marie Curie, and her daughter Irene, striking. Marie and Irene pass in and out of the book at various places, but their story is never properly told.
Marie and Irene Curie.
Wikimedia Commons
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This is particularly odd given that both were involved in experimental work in particle physics, and one was a Nobel laureate. Ultimately, the book doesn’t fully heed its own warning, and what we are left with is a history of physics with notable gaps. This is a shame, since it was an opportunity to set the record straight.
Limitations
Overall, The Matter of Everything suffers from some serious limitations. It claims to be a history of 20th century physics but, at best, tells the story of experimental particle physics.
Theoretical work is missing, as are some of the experiments that relate to gravitational work in physics. The book also has significant gaps when it comes to the scientists themselves.
I thus don’t recommend the book as a complete history of 20th century physics. But read it if you’re interested in particle accelerators, and if you’re keen to know why they matter so much to everyday life, and not just big science.
Authors: Sam Baron, Associate professor, Australian Catholic University 
