B. Ishak

The Physics and Evolution of Active Galactic Nuclei by Hagai Netzer

by the scale of the published literature. The present authors have come to the rescue of those new participants in the graphene research and development field. The three authors have been active researchers who have indeed ridden the wave of development. But here they have been prepared to stand back for a while to distil their understanding in a highly readable textbook. In doing so, they also have sought to ‘answer the payers of many colleagues, who have had to struggle in a nascent field characterised by a huge body of research papers but very little introductory material’. The book assumes a basic knowledge of solid-state physics on which they build an impressive edifice, which houses careful treatments of the electronic structure and transport properties of graphene-related systems. The development of these topics in the seven main chapters of the book is supplemented by material in appendices which treat e.g. the formalism of Green’s functions. Chapter 8 of the book is given over to an overview of the presently perceived ‘most promising graphene applications in information and communication technologies’. To underline the pedagogic role of the book, the technical chapters contain exercises for the reader to explore. The authors also have made additional problems (and their solutions) as well as other material online. Overall, this is an exceptional contribution to furthering graphene research, development and applications. It is to be hoped that the authors’ many colleagues and collaborators will demonstrate their true appreciation of this achievement by ensuring that the growth in the sales of this book is as explosive as that of graphene research.

Gravitational lensing, by S. Dodelson: Scope: textbook. Level: postgraduate, researcher

That light can be deflected by gravity is one of the most fundamental phenomena in nature. Gravitational lensing, as it is called, is one of the celebrated outcomes of relativity that readers almos...

Asteroids: astronomical and geological bodies, by T. H. Burbine: Scope: reference, textbook. Level: undergraduate, specialist

SU(2) field configuration in which there is a non-trivial connection between directions in field space and directions in coordinate space, appears to have – and therefore has – a magnetic charge. So magnetic monopoles can be created simply by a topologically non-trivial solution to the SU(2) gauge field equations – the ‘hedgehog solution’, as Polyakov called it. The lectures in this book contain interesting remarks on ‘whole numbers in physics’, and it is indeed interesting and thought-provoking that both quantum theory and topology can lead to similar situations. The Bohm–Aharonov effect is another topic more or less familiar in physics, with a definite reliance on topology; and more recently much of the progress in superconductivity and superfluidity has relied on topological insights. This well-produced book provides a most welcome introductory survey of the many areas of condensed matter physics in which topological ideas have played a significant role.

Introduction to modern magnetohydrodynamics, by Sébastien Galtier: Scope: textbook. Level: advanced undergraduate, postgraduate

In the final chapter, Townsend summarises the key issues he presented in previous chapters, and then offers recommendations on what is ‘needed in the immediate future’ (285). We are vulnerable to catastrophic natural events, but technological advances mean we also ‘are increasingly likely to suffer from natural events that previously were irrelevant’ (285). Thus, unlike natural events that are both rare and outside our control, when dealing with natural events – such as sunspots – that are ‘regular features’ with huge potential for damage, we can forecast their impacts and prepare plans to mitigate the negative consequences (285). What makes this books a ‘must read’ is that Townsend not only outlines key problems we as a society must confront, but provides solutions, such as working to reduce our dependence on technology and resources (286); using hindsight on solar emissions and sunspots and their impacts on technology to plan for the future; and reducing obsession with ‘material goods and profit’ (290) – changing this ‘deeply ingrained set of attitudes’ through increased knowledge (290). He also advocates sustainability, using resources without depletion (improved health, less obesity and food waste) (292). He laments that although life expectancy has increased, youth is less fit and diseases such as obesity are rising. Townsend explains that in the UK, a ‘vigorous anti-smoking campaign’ has reduced cancers and diseases caused by cancer, showing that ‘political actions of this type are effective and should continue with more vigour’ (294). Townsend concludes that we need to recognise the ‘two faces of technology’ and explains that two scenarios could evolve – (1) ‘natural events or wars will destroy those dependent on technology to survive’ or (2) worse – the ‘dark side of technology may lead to total extinction of our human race by engaging in a global war’ (e.g. use of chemical weapons followed by worldwide starvation) (303). However, he says that by recognising our mistakes, there is hope to correct them. Furthermore, we need to motivate the public and politicians to actively spread this message that global change is urgently needed in order to prevent catastrophic damage. This short but ambitious book provides a critical overview and explanation of the wide-ranging impacts and vulnerabilities to technology, but also provides guidance and solutions for how to handle the potential dangers we face. Townsend ends on a hopeful note that ‘aggressively pointing out the disaster scenarios we are self-generating’, is the first step to recognising our errors and hopefully can lead to attempts to fix them (304).

An Introduction to Galaxies and Cosmology (2nd Edition), edited by Mark H. Jones, Robert J.A. Lambourne, and Stephen Serjeant

thing about the distant stars and galaxies, the answer is EM radiation, the most wonderful tool in observational astronomy. There are many radiative astrophysics processes associated with the celestial phenomena that we observe in the Universe; and the reason that we know anything about them can all be attributed to the EM radiation detected from one kind of process or another. In fact, we would never have detected or be able to explain these events had it not been for processes like the blackbody radiation, synchrotron radiation and braking radiation (commonly called by the German name bremsstrahlung) and other processes. In its simplest definition, a blackbody is an object that absorbs all the light (the less fancy name for EM radiation) and turns black. An ideal blackbody emits the same amount of energy back to the environment. This energy can be plotted vs. wavelength (or frequency) to produce a distinct curve that shows that a blackbody radiates energy at all wavelengths with one distinct peak. The higher the temperature, the higher the intensity (or energy density) is but the lower the peak wavelength. From such a plot, astronomers can ascertain the temperatures of the Sun, the stars and other celestial objects using a simple equation of T = 0.0029/λmax. 3 In the plot of the spectral energy distribution of the extragalactic background radiation, the cosmic microwave background (CMB) is seen to be the most dominant. The CMB displays a perfect blackbody spectrum at a peak wavelength of 1 mm which gives a temperature of 2.725 K. Going back all the way to the infant Universe, the CMB is believed to have been formed 3 × 10 years after the big bang. At that time, the temperature of the Universe was 3000 K, a lot higher than it is now. Thus, the blackbody spectrum we see at such a low temperature today is a sign that the cosmos has since cooled. Besides cosmology, radiative process can be used to explain one of the celebrities of the Universe i.e. the Crab Nebula. Purportedly seen in China in 1054 – there is a doubt whether or not the Chinese ‘guest star’ is actually the Crab Nebula [1] – the nebula gives out a blue-white emission that has baffled astronomers for a long time. But it is now known that the emission is actually the polarised light produced by a process called synchrotron radiation. Radiation is not the only astrophysics process applicable to celestial objects and phenomena. Other processes like gravitational lensing and relativity, to name just two, are also important. The twin quasars, Q0957+561, for instance, are actually just the one quasar; but the bending of light by gravitational field near a galaxy in between the quasar and the observer, causes it to be observed as two separate images. Theorised by Einstein, gravitational lensing is an effect of relativity and the twin quasars have confirmed it observationally. This text is actually a lecture note by the author during his teaching at the Massachusetts Institute of Technology. It is for students who have taken all the fundamental physics classes such as electromagnetism, mechanics, quantum mechanics, statistics and thermodynamics. Expect it to be tough as some of the materials are difficult for undergraduates (this depends on the readers’ own college or university, obviously) and about semi-difficult for early graduate students. Focusing on the analytical aspects of astrophysics processes that are seen in the Universe, readers are guided through their step-by-step derivations. This means that sufficient mathematical knowledge is also required. The chapters are complete with illustrations – some real results, some cartoons – for further understanding and come with problem sets for sections and subsections; but alas, no answers are given. This is so because readers are encouraged to work them out themselves and then discuss them, preferably in a seminar setting as recommended by the author. Therefore, it is best suited for those whose instructors have adapted the book as part of similar course as teachers could get the password to unlock the answers.

Astrophysics Processes: The Physics of Astronomical Phenomena, by Hale Bradt

one in some detail. Section 2.1.3 of the volume is entitled ‘Contact resistance and Schottky barriers’. Here, mention is made of a work function whose definition is given using the same symbol, φM, for the metal work function and an undefined potential. The sentence defining the work function culminates in the equation: φM = φM/q. If that were not confusing enough, the subsection includes Figure 2.2 whose purpose seemingly is to illustrate the metal–semiconductor phenomena of charge accumulation and depletion, but those concepts are not mentioned in the corresponding text. (As a detail, it seems that the figures in Figure 2.2 may be for an MIS structure, but due to the lack of text this cannot be confirmed.) It is stressed that the forgoing is far from being an isolated example with which this nasty reviewer seeks to berate the authors. Suffice it to offer a few other examples chosen almost randomly: the definition of transmittance (given on the same page as the above section) is incorrect; a section on Kramers–Kronig relations refers to the sum rules’ without having defined any. When the authors come to write down the Kramers–Kronig relations they use different font size for the right-hand sides of the equations. Having rehearsed such basic concepts attention is turned towards advanced topics. Here, one expects clarity, but instead one finds that the text is heavily reliant on citations of the literature with little or scant attention to detail. Somehow the reader is expected to have jumped from one needing to be taught about Schottky contacts to one who readily appreciates the subtleties of published research. Thus, in discussing trends in materials for RF electronics (section 1.1.4) and having mentioned carbon nanotubes (CNTs) the authors state: ‘It is well known that CNTs are cylinders of nanometer diameter of a graphene sheet wrapped up to form a tube’. But the reader seemingly needs no discussion of graphene itself? Moreover it is assumed that the reader is able to appreciate (without any further explanation) that single wall CNTs ‘can be uniquely described by a double index or chiral vector’. Such a vector is displayed in the related Figure 1.3, but how one should find that vector is not explained. Apart from CNTs, other materials are discussed, but the reader is referred to the literature for details beyond a basic statement of properties or applications. In the view of this reviewer this volume is entirely out of focus. Neither does it provide a firm foundation in the basic physics of the topics being considered nor does provide a clear overview of the state-of-the art. One holds that a book should add some value by providing the reader with some insight into the information can be gleaned from the literature. In this case, the authors simply catalogue the topics of interest and give a little or no explanation or detail. Often the sentences are often disjointed and sometimes devoid of meaningful content. The authors include a relatively large number of figures and graphs in the volume but rarely do such figures add to the experience of the reader. A classic example is Figure 1.15 which presents experimental measurements of scattering coefficients. In the figure, the same symbols are used for different coefficients and, due apparently to large noise in the measurements, no trends are discernible. No text is offered to explain the main message of the figure. The authors are fond of lists. In the opening chapter they list ‘Three main thrusts’ those thrusts are defined by lists of technical topics which are not explained. At the end of the book attention is turned to challenges for future applications. These also need a couple of lists, but the reader must seek the details from the literature. But in the end the authors get tired of providing references and describe work by Vardaxoglou without offering a reference. Presumably the interested reader can find that for themselves? Although the authors may think otherwise, it gives this reviewer no pleasure to draw attention to some of the numerous faults in this monograph. One hopes that the Focus series editor may encourage its authors to think more carefully about their target audience and to prepare volumes to meet such readers’ needs.

Nearest Star: The Surprising Science of our Sun (2nd Edition), by Leon Golub and Jay M. Pasachoff

How did the Sun evolve, and what will it become? What is the origin of its light and heat? How does solar activity affect the atmospheric conditions that make life on Earth possible? These are the questions at the heart of solar physics, and at the core of this book. The Sun is the only star near enough to study in sufficient detail to provide rigorous tests of our theories and to help us understand the more distant and exotic objects throughout the cosmos. Having observed the Sun using both ground-based and spaceborne instruments, the authors bring their extensive personal experience to this story revealing what we have discovered about phenomena from eclipses to neutrinos, space weather, and global warming. This second edition is updated throughout, and features results from the current spacecraft that are aloft, especially NASA’s Solar Dynamics Observatory, for which one of the authors designed some of the telescopes.

Foundations of Quantum Gravity, by James Lindesay

Quantum gravity is about incorporating the two most enigmatic subjects in physics, namely, quantum mechanics and general relativity. Quantum mechanics has the infamous uncertainty principle at its core such that the momentum and the position of a particle cannot be simultaneously measured no matter what while general relativity that describes gravity is known for its equivalence principle that results in light being bent in curved space-time. It goes without saying that whenever these two are involved, the mathematics is rigorous. Thus apart from some understanding in both theories, some expertise in statistical physics is also required in order to understand the concept of quantum gravity. But the author’s explanations are very to the point so there is no need to actually work out the equations. Plus, there are many diagrams included in every chapter that definitely help in simplifying the math as well as a set of addenda at the end for those requiring further technical details. However, this book is very hard going and also very dry. It is not the type that readers can read at leisure, irrespective of how much interest they have in acquiring new knowledge unless they are in the habit of mulling over some deep questions. Needless to say, anything quantum is far too advanced for many. In fact, no one really understands quantum physics according to Richard Feynman. So if the readers are not theoretical physicists, they would have to be philosophers to appreciate the contents. Still, the author should be praised for his effort in answering some of the puzzling fundamental questions even if they are his own unanswered or unanswerable dilemmas as he so graciously admitted.

Dark Matter and Cosmic Web Story by Jaan Einasto

Dark matter is literally a matter that is dark or unseen yet very much present in the Universe. As early as the beginning of the twentieth century, scientists have been pondering its nature but as customary for something that is new and novel, the concept was alien thus not readily accepted by most. Today, from observations and theoretical models, we know that dark matter comprises 25% of the energy budget of the Universe. In a large sky survey of nearby galaxies, scientists have observed the presence of galactic filaments, i.e. the threads that interconnect superclusters of galaxies to create what is known as the cosmic web. The structure of the web is believed to contain information pertaining to dark matter. This book is a private story of how research in dark matter and cosmic web in Estonia become unfold. In doing their research, the scientists experienced obstacles such as lack of pecuniary resources and difficulties in visiting the west. Works done by Estonian scientists were also not recognised or gone unnoticed until similar results were confirmed by their western counterparts, usually years and years later. For example, almost all the crucial features of the cosmic web have long been established by Estonian astrophysicists and even discussed at the 79th IAU Symposium in Tallinn in 1977 before similar results were obtained from the CfA Redshift Survey in 1989 [1]. There are many anecdotes, reflections and quotations sprinkled all over the chapters. At the end of every chapter, there is a section devoted to Tartu Observatory so its evolution from the early days of conception until now can be seen. Also included is the author’s personal computer revolution from slide rule to iPhone and how it has influenced his research. It is interesting to note that back in the mid 70s, he managed to calculate a galactic model using only a limited-memory, programmable pocket calculator. Equally interesting is that the author had also independently constructed a four-axis mount for satellitetracking telescope [2], like the one later manufactured by Zeiss. As usual, when reading someone’s own account of their journey, readers will find some repetitions but these only enhance the authenticity and originality of the story. There is no self-aggrandisement, only sincerity and honesty. Despite the narrative being personal with some digression every now and then, the science is still invaluable. There is a lot to be learned about dark matter and cosmic web here. In fact, the relax atmosphere creates by the story makes it a bit easier to understand them, too. This book is not only suitable for scientists but also historians – armchair or otherwise – as those unfamiliar with the history of Estonia will be able to glean it from the author’s perspective.

The First Galaxies in the Universe, by Abraham Loeb and Steven R. Furlanetto

ing the strength of physics to studying living systems. The book consists of two main parts. The first part gives an introduction and demonstrates how to formulate physics problems for biological phenomena, the example used is photon counting in vision. What is the minimum photon threshold detectable by the eye? The question inevitably sparks intrigue for physicists. It is this extraordinary ability of articulating and presenting problems in the most interesting light that makes the book both immensely enjoyable to read and its content highly original. The second part focuses on exploring various biological examples. They are grouped into three chapters, under the umbrella of three ideas central for living organisms, which are, the importance of noise, the non-requirement of fine tuning and the challenges of representing information. The book is primarily aimed at physics graduate students. Nonetheless, researchers working in the field will also benefit from this refreshing mode of dissecting biological problems. The readership can easily extend to any researchers with a strong physics or mathematics background who wish to acquire skills in studying biological problem quantitatively. There is no doubt the book is technically demanding. The mathematics and background ideas are drawn most heavily from statistical mechanics but a wide range of physics topics are also touched upon including mechanics, electromagnetism, quantum mechanics and a few others. The level expected is what a competent physics graduate student should posses. A good foundation and command of physics and mathematics as well as basic level of biology are not only important for making steady progress through the book, but also for appreciating the subtleties of many problems posed. To guide and engage readers through the learning process, the author has incorporated problems throughout the book, a total of 200 problems. While many of the problems are straight forward to work out the answers, some, on the other hand, will require much effort. Solutions to those problems would be especially helpful but is lacking. A few supplementary materials have to be downloaded from Princeton University Press website for the book. In summary the book goes beyond than being a structured material for readers to learn about biophysics; it takes readers on an incredible journey in discovering fascinating ways in which biological phenomena can be viewed and studied. The technical adroitness and more importantly, the unique way of thinking about biological problems, in the reviewer’s opinion, makes the book a must-read for any aspiring biophysicists.