In the early days of the universe, there was darkness. Until somebody said, “let there be light”? Not quite. In First Light, astrophysicist Emma Chapman introduces you to ongoing research into the first billion years of our Universe and the birth of the first stars. Popular science at its finest, this book challenged me pleasantly but was above all—with apologies for the terrible pun—enlightening.

First Light: Switching on Stars at the Dawn of Time, written by Emma Chapman, published by Bloomsbury Sigma (a Bloomsbury Publishing imprint) in November 2020 (hardback, 304 pages)

Though I have never given it much thought, the idea of there being a first generation of stars seems logical once you mention it. As Chapman shows, there is a gap in our understanding of what, exactly, happened during this time. Ongoing research shows this to be an unusual period, going by such evocative names as the Dark Ages, the Cosmic Dawn, and the Epoch of Reionisation.

Before we get to these, Chapman introduces you to the basics in the first four chapters. To grasp the science, you will need to understand the properties of light (its dual wave-particle nature and its high but not unlimited speed), stellar classification (from young to old: Population I, II, and III stars), the Big Bang and the expansion of the universe, and how stars are born. With that sorted, she then walks the reader through those first billion years.

An awful lot happened in the first three minutes after the Big Bang. Protons and neutrons were able to combine in a process known as nucleosynthesis within ~14 seconds. Within minutes, this process ended and the early Universe was full of hydrogen and helium isotopes. Electrons were still too energetic to bind to them to form atoms proper. It would take another 380,000 years of the Universe expanding and cooling down for so-called recombination to take place and hydrogen atoms to form. Something else happened at this point: the Universe became transparent to radiation. Before this time, “we cannot see anything with light […] because the environment is too volatile to allow photons to travel on unimpeded paths to our telescope” (p. 84). Although photons were released during these steps, the continued expansion of the universe meant their wavelengths increased (a process known as redshifting) until they left the visible part of the electromagnetic spectrum. With stars not yet born, the Universe entered its Dark Ages.

“[…] stellar archaeology […] tries to find quiet parts of the Universe, so-called stellar tombs […] , where rare, light-weight Population III stars might have survived until now.”

And yet, something was stirring in the darkness. Hydrogen gas coalesced into clouds until some became dense enough to ignite fusion, the first stars flickering into life. This was the Cosmic Dawn, some 180 million years after the Big Bang. Chapman talks at length about these Population III stars as they were unique. Consisting of nothing but hydrogen, they were huge (hundreds of solar masses) and short-lived (millions of years). As fusion consumes a star’s hydrogen, they go through several cycles: “with heavier and heavier metals created in onion-like shells” (p. 153). (To astronomers, all elements heavier than helium are simply “metals”.) This continues until you hit iron: photons released in these fusion reactions as so energetic that they destroy the iron again and the whole thing goes supernova. The first Population III stars thus seeded the cosmos with heavier elements, paving the way for new iterations of star formation.

There are two big narrative threads regarding Population III stars. The first was, for me, rather technical and challenging, so hold on to your helmet while I attempt to explain it. This has Chapman talk about how to find the first stars using the radiation emitted by hydrogen gas that is cooling down, which has a very particular wavelength. This involves the abstract property of an atom’s spin state and the emission of a 21 cm wavelength photon when a hydrogen atom goes through a spin-flip transition to settle in its energetically least excited state, its ground state. The experiment detecting this particular radiation incidentally also provided evidence for the existence of dark matter. In the early Universe, dark matter was condensing to form filaments that formed the gravitational skeleton, if you will, around which regular matter such as hydrogen gas ended up condensing. As such, our universe has a large-scale architecture that resembles a cosmic web of clusters of galaxies connected by filaments of galaxies.

The second point is that Population III stars are still theoretical entities: we have never observed any. This leads Chapman down two very interesting avenues of research. The first is known as stellar archaeology and tries to find quiet parts of the Universe, so-called stellar tombs (astronomers get all the cool names), where rare, light-weight Population III stars might have survived until now. The other, complementary approach searches for ancient dwarf galaxies that have escaped the galactic cannibalism through which galaxies grow by gobbling up smaller ones. This would provide information about the environment in which these first stars formed.

“[…] this subject could have ended up being impenetrable in the hands of a lesser science communicator. [Chapman] excels at explaining the astrophysics and uses some imaginative metaphors […]”

Lastly, there is the Epoch of Reionisation. The Big Bang initially resulted in a Universe with nuclei that did not yet have electrons bound to them; it was ionized. Recombination resulted in a Universe filled with neutral hydrogen. But something happened to reionise the Universe’s hydrogen, a state that persists to this day. Research is ongoing to find out what that something was. Early quasars emitting X-rays have been implicated, but photonic emissions by Population II stars are another likely contributor. Similarly, astronomers are trying to constrain the when, with current estimates suggesting that the process took some 500 million years and was complete 1 billion years after the Big Bang.

For a biologist such as myself—admittedly one fascinated by astronomy—this subject could have ended up being impenetrable in the hands of a lesser science communicator. Chapman has received various commendations and prizes and is a well-known public speaker. She excels at explaining the astrophysics and uses some imaginative metaphors. Why do some particle interactions require a low-energy environment? “Try hugging someone sprinting in the opposite direction and you’ll understand why sometimes slower is better when it comes to interactions” (p 130). How do you find a black hole? Through its gravitational effect: “Like spotting someone well known in a shopping arcade, you are unlikely to see that person, but you know that something is happening from the mass of people heading to one point from all directions” (p. 221). Furthermore, she makes good use of subheadings in the text, includes diagrams to visualize abstract concepts, and ends each chapter with a helpful recap.

Although the focus of her writing remains firmly on the science, she delivers it in a conversational style. There are some nerdy jokes, but never too many. There are lyrical passages, but used in moderation. For example, the Big Bang “[…] is a theory that has been forced on our uncomprehending three-dimensional brains, incapable of visualising infinity but able to understand the overwhelming evidence” (p. 70), while stellar archaeology is described as “[…] a field that has moved from seeking the first stars to conversing with the second stars and hearing tales of their ancestors” (p. 178). Peppered throughout are historical episodes, e.g. the accidental discovery of the Cosmic Microwave Background radiation (which features two very unlucky pigeons) and its recognition as the afterglow of the Big Bang. And Chapman highlights some of the underacknowledged female pioneers such as Cecilia Payne-Gaposchkin, who proposed stars were primarily made of hydrogen and helium, Vera Rubin, who provided evidence for the existence of dark matter, or the women at the Harvard College Observatory, who classified stars on an industrial scale.

By now, I have reviewed eleven of the almost seventy titles on the Bloomsbury Sigma imprint. Though billed as popular science, these are not boilerplate books, but cover specialist, cutting-edge topics and provide a pleasant intellectual challenge. Invariably, they are written by skilled science communicators who are experts in their field and are willing to spend several years on a book. And judging by the acknowledgements I have read so far, they go to great lengths to seek advice from peers and solicit colleagues to proofread and comment on their manuscripts. In that sense, First Light represents everything I appreciate about the Bloomsbury Sigma imprint. Next to a wildly fascinating book, it is another shining addition to their roster.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

First Light

Other recommended books mentioned in this review:

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This is the second of a two-part dive into the story of oceans on Earth and elsewhere, following my review of Ocean Worlds. That book gave a deep history of how our oceans shaped Earth and life on it and briefly dipped its toes into the topic of oceans beyond Earth. Alien Oceans is the logical follow-up. How did we figure out that there are oceans elsewhere? And would such worlds be hospitable to life? Those are the two big questions at the heart of this book. If there is one person fit to answer them, it is Kevin Peter Hand, a scientist at NASA’s Jet Propulsion Laboratory and their deputy chief for solar system exploration.

Alien Oceans: The Search for Life in the Depths of Space, written by Kevin Peter Hand, published by Princeton University Press in March 2020 (hardback, 248 pages)

A major question in astrobiology is whether the evolution of life on Earth is a fluke, or whether life is bound to pop up wherever conditions are favourable. Hand very neatly frames this in the bigger history of science. Over the centuries, we figured out that the laws of physics, chemistry, and geology work beyond Earth. But “when it comes to biology, we have yet to make that leap. Does biology work beyond Earth?” (p. 15). What we have learned is that life as we know it needs water. And though there is no shortage of theories on the origins of life, oceans are very likely where it started, and thus a logical first place to start looking for answers.

If you have any interest in astrobiology, you will probably have heard of the concept of a habitable zone or Goldilocks zone where, based on the distance to a star, conditions for life are just right. Not so close as to be too hot, nor so far as to be too cold. Earth obviously falls in that zone. Next to many minor insights, Alien Oceans had three major eye-openers for me. This was the first one:

There are other Goldilocks zones.

Depending on the details of their orbit, moons can experience such strong tidal tugs from their parent planet that the constant squeezing and stretching of the rock creates enough heat through internal friction to sustain liquid water. The physics of water helps, as it has a seemingly mundane but rather unusual property. Ice floats. When water solidifies, its density decreases slightly. What this means for moons is that the liquid water exposed to the cold of deep space freezes and forms a protective icy shell. Most liquids do not have this useful property. When they freeze, they sink to the bottom exposing more liquid until all of it is frozen solid. To top it off, ice is also a good thermal insulator, helping such ocean worlds retain heat. Maybe I have been hiding under a rock, but this was revelatory for me. Suddenly, the amount of cosmic real estate suitable for life has increased quite dramatically. And we have some of it right here on our doorstep.

“Over the centuries, we figured out that the laws of physics, chemistry, and geology work beyond Earth. But “when it comes to biology, we have yet to make that leap. Does biology work beyond Earth?“”

The existence of oceans in our solar system and how we gathered the evidence is one of the two major threads running through this book. Hand examines this in detail for Jupiter’s moon Europa, which has been studied in the most detail. Three types of data are typically gathered: spectroscopic, gravimetric, and magnetometric. This is where Hand gets fairly technical, though, fortunately, he extensively uses comparisons with everyday concepts and technologies to help you understand the underlying (astro)physics. Without retreading his careful explanations, in Europa’s case, these different strands of data all converge on a moon with an icy shell and a substantial subsurface ocean some 80–170 km thick as the best explanation. Mixed in with this narrative are the details and many technical setbacks of the Galileo mission that are nail-bitingly tense in places.

Similar missions and measurements have been done for Saturn’s moons Enceladus and Titan, Jupiter’s moons Ganymede and Callisto, Neptune’s moon Triton, and Pluto. The evidence for oceans gathered so far gets less robust in this order, but there are some notable variations on the theme. Enceladus ejects spectacular plumes of water and carbon compounds that were photographed and sampled by the Cassini–Huygens mission. Ganymede, meanwhile, is so large that the bottom of its ocean might consist of an exotic form of dense ice, ice III, formed at very high pressures not seen on Earth, meaning its ocean is sandwiched between two layers of ice.

So you have found exo-oceans. Now what? Can we expect to find life here? That is the second major thread. Hand identifies five conditions for life to emerge: a solvent such as water, chemical building blocks, an energy source, catalytic surfaces, and time. Interestingly, there is a gap between two schools of thought. The top-down explanation deconstructs life backwards in time until we arrive at an RNA world, but how did that get started? The bottom-up explanation has shown that life’s basic building blocks such as amino acids exist in space, but how do we go from there to larger functional molecules?

“There are other Goldilocks zones. Moons can experience such strong tidal tugs that the heat released by internal friction can sustain liquid water.”

This was the second major eye-opener for me: “Our environment is full of chemical disequilibrium […] there are reactions just waiting to happen. […] The metabolisms that drive life accelerate reactions in the environment, releasing energy faster than would have occurred without life” (p. 144). Hand takes a leaf out of Nick Lane’s book The Vital Question (which, shame on me, I still have not read) when he enthusiastically concludes that “the why of life is metabolism” (p. 146), offering the universe a pathway to increase entropy faster. These are remarkable ideas that give a whole new meaning to philosophical questions on the meaning of life.

The third and final eye-opener concerns the need for a catalytic surface, which is where Hand circles back to oceanographic exploration here on Earth, a recurrent theme in this book. When the submarine Alvin discovered hydrothermal vents in 1977 and found them teeming with life, these quickly became a popular alternative explanation to warm tidal pools as a place where life could have started. These so-called black smokers are powered by magma rising to the surface at mid-ocean ridges, jetting out superheated water of over 400 °C. Though volcanism and tectonics are, or sometimes were, common processes on many solar system bodies, there is another option. Alkaline vents, first discovered in 2000 at the Lost City hydrothermal field, are powered by exothermic (energy-releasing) reactions between water and mineral-rich rock, heating water to a more gentle 70–100 °C. All these need are the right rocks with cracks in them so water can percolate down.

“In addition to hydrothermal vents, alkaline vents are another place where life might have started. All these need are the right type of rock with cracks in them so water can percolate down, no plate tectonics needed.”

Hand raises many other interesting questions towards the end of the book, of which I will mention just three. One, life’s metabolic reactions require so-called oxidants, oxygen being “the most glorious of oxidant” (p. 162), but how would these get down into subsurface oceans? Two, how contingent or convergent is the evolution of life’s biochemistry? Carbon is a suitable building material for life as it is “hands down the best team player on the periodic table” (p. 212). But to these options, or can we sketch a periodic table of life with other, weirder possibilities? And three, how should we seek for signs of life? What makes a good biosignature? This is discussed far more in-depth in Life in the Cosmos, but Hand considers three types of evidence.

Alien Oceans limits itself to oceans in our solar system, not touching on the topic of exoplanetary oceans. Given this is not Hand’s expertise, that is reasonable. He also glosses over the question of what aliens might look like, though he speculates on the likelihood of intelligent life in ice-covered subsurface oceans. Even without these topics, Alien Oceans is information-dense, requiring me to make a summary, and then a summary of that summary while preparing this review. Nevertheless, it is an intellectually very rewarding book and the many analogies make it accessible. I enjoyed it as a follow-up to Ocean Worlds but it is a fine standalone book. Terribly fascinating, Alien Oceans makes a convincing case for exploring the moons in our solar system in the search for extraterrestrial life.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Alien Oceans

Other recommended books mentioned in this review:

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You would think that after centuries of studying spider webs we have a pretty good grasp of them. Yet a thorough, book-length review of their construction, function, and evolution has been missing. Emeritus Professor William Eberhard has taken on that colossal task, based on his nearly 50 years of observing spiders and their webs. Some works go on to define their discipline. Spider Webs has all the trappings of becoming the arachnological benchmark for many years to come.

Spider Webs: Behavior, Function, and Evolution, written by William G Eberhard, published by the University of Chicago Press in August 2020 (hardback, 658 pages)

Spider Webs is big. Really big. This arachno-tome intimidates as much as it edifies. Some stats: A 21 × 28 cm, 658-page hardback containing ten chapters sprawling over 581 pages, 39 pages of references, and a 36-page index. A 12-page table of contents revealing the book’s highly nested structure, many sections going down 4–6 levels (you may find yourself reading section 3.3.4.2.2.5 on the importance of UV reflectance of silk stabilimenta). Almost 300 black-and-white photos and drawings of webs, often of species not included in previous literature. And if that was not enough, a 91-page online supplement with small print containing additional observations, tables, and musings. What makes these numbers mildly terrifying is that Eberhard almost apologetically mentions he avoids so much detail as to overwhelm the reader, and that “a truly thorough summary of our current knowledge would be crushingly dull” (p. 10). Yes, 750 pages is what Eberhard holding back on his encyclopedic knowledge looks like.

So, what is in the book? Eberhard includes much older literature often skipped over in review papers, and has included numerous of his own unpublished observations. He starts with a chapter on the spider’s hardware (silk glands, spinnerets, and legs) and ends with two chapters on evolution. The construction and function of webs in chapters 3–8 forms the core of the book, though the order in which topics are discussed is not necessarily how a spider proceeds. Thus, Eberhard begins with an extended chapter on the function of orb webs, including 45 pages discussing incorrect and unsupported ideas, followed by a chapter on the many trade-offs between different properties and parts of a web, e.g. tensions on lines or the number and spacing of radii and spirals of sticky silk. Having discussed function, Eberhard then turns to how webs are constructed and what cues spiders use. For non-orb weavers our knowledge is so fragmented that a short chapter summarises “scattered bits and pieces of information” (p. 273). Orb weavers have been much better studied, and the descriptions of building behaviour (how a spider moves its legs and body to make an orb web) and the cues used to decide where to lay and attach lines span 120 pages in two chapters. And thus the first step in the process, how a spider decides where and whether to build a web, is discussed last. The properties of spider silk are only discussed briefly, and I refer readers wanting more details to two books by Catherine Craig.

“[…] published descriptions of webs and spider behaviour make it appear as if there are only a few ways of doing things, but that is a limitation of our language, not a reflection of reality.”

Spider Webs is not a particularly difficult book. Eberhard wanted it to be accessible to the general reader and has by and large succeeded, I think. Any reader serious about tackling a book this size is probably already familiar with the terminology and conventions used here. If not, no harm can become the spider novice from first reading e.g. Biology of Spiders. Spider Webs is, however, particularly rich in detail and minutiae. This is where the highly nested chapter structure comes into its own. I found it useful to bookmark the contents and refer to them while reading to keep my bearings. Throughout, there are summaries in subsections and summaries at the end of chapters, and summaries of summaries. The take-home messages are spelt out clearly, and I will highlight a few prominent ones.

Eberhard warns against typology: published descriptions of webs and spider behaviour make it appear as if there are only a few ways of doing things, but that is a limitation of our language, not a reflection of reality. “The” web does not exist: there is much variation on the level of families, genera, species, and even individuals in the details of web construction, much of it poorly documented. There are fascinating variations on the theme (the elongated ladder webs to catch moths are but one of many examples included here). And this is before you even consider the material here on non-orb weavers. Tying in with that, the idea that spiders are little web-spinning automatons is mistaken. True, freshly hatched spiderlings succeed at their first attempt, and there is little indication that spiders improve with practice, but they combine information from a wide variety of cues (environmental and otherwise) during web construction and can modify their behaviour as needed. Eberhard discusses 10–16 cues, depending on how you count and which ones you consider independent of each other.

“A particular sticking point is ecological realism. Much data that is collected […] is flawed or of questionable relevance to spiders.”

Orb webs are not optimum structures: “[…] there is a veritable minefield of variables that can affect the chances that a web will capture prey” (p. 78). Despite claims to the contrary, demonstrating optimality is very hard and, Eberhard believes, has never been done empirically. Nor are orb webs the pinnacle of evolution. Despite the higher-level phylogeny of spiders not being fully resolved, there is little doubt that orbs have evolved and secondarily been lost again multiple times. The large-scale evolutionary pattern is one of both high diversity and frequent convergence, resulting from “an especially ancient and thorough exploration of the adaptive space associated with webs” (p. 479). In other words, given hundreds of millions of years of evolution, is there anything spiders have not tried? (Actually, yes, as shown here by some interesting comparisons with other silk-producing insects.)

Next to everything we know, Spider Webs is as much a book about what we do not know. Eberhard reviews the many suggested functions of web traits, only to point out that, bar preliminary results or casual observations, we often lack empirical data to decide one way or another. He concludes an extended discussion on the possible functions of silk stabilimenta with the admission that it sounds like a “litany of frustration” (p. 180). I had not heard of them before, but they will have even seasoned arachnologists pull out their hair. A particular sticking point is ecological realism. Much data that is collected (on e.g. number of prey available in the environment or their nutritional value) is flawed or of questionable relevance to spiders: “the cues that are used by spiders are not necessarily the same as the variables that are commonly measured by researchers” (p. 435). And we must not forget that spiders evolved in habitats undisturbed by humans until recently. Most data is now gathered in environments that spiders did not evolve in. He admits this might seem like: “nihilistic surrenders to hopeless ignorance” (p. 87).

“Spider Webs is one of those rare books that sets a discipline’s research agenda for decades to come and cannot be ignored.”

Eberhard berates fellow arachnologists throughout, e.g. for not documenting variation in construction behaviour and design within species, or the lax use of the word “sheet” when describing webs. But he is equally critical of his own failures and owes up to his changes of mind. For instance, his enthusiasm for using models to determine the advantages of different web designs has vanished, and he is no longer the proponent he was of using artificial webs to estimate prey availability. Table 9.4 lists beautiful ideas slain by ugly facts and “gives a sampler of disappointments (with my own failures perhaps over-emphasized)” p. 480. As a bonus, there is a 15-page table in the supplement with hundreds of unanswered questions for future students and researchers to pursue. One might think Eberhard a curmudgeon, but that would ignore the fact that nature is complex and does not readily yield to the order that we wish to impose upon it. Here is someone who has studied spiders intensely and I must agree with his outlook that “intellectual rigor is useful; little is gained (and much is lost) by ignoring the limitations of data to support or discard particular conclusions” (p. 87).

Spider Webs is one of those rare books that sets a discipline’s research agenda for decades to come and cannot be ignored. This book has set the bar and has set it high. For professional arachnologists this is a vital and invaluable reference work. For serious spider enthusiasts it is an absolute treasure trove. Beyond the spider community, however, there is much here of interest to ethologists and evolutionary biologists. Readers interested in more spider talk might also want to check out my Q&A with Eberhard published over at the NHBS Conservation Hub.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Spider Webs

Other recommended books mentioned in this review:

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When Google Earth first launched in 2001, I, like many others, found myself poring over satellite imagery. Identifying familiar and unfamiliar landmarks always brought a certain thrill, and spotting craters was part of that. But to properly map impact structures, you need a better dataset. The stunningly produced Terrestrial Impact Structures is a large-format atlas that maps all currently accepted ones, plus some likely candidates, and makes for an instant must-have reference work for any geology or astronomy library.

Terrestrial Impact Structures: The TanDEM-X Atlas (2-volume set), written by Manfred Gottwald, Thomas Kenkmann, and Wolf Uwe Reimold, published by Verlag Dr. Friedrich Pfeil in November 2020 (hardback, 608 pages)

This atlas is, furthermore, a beautiful example of one field of scientific enquiry playing off another. The TanDEM-X in the subtitle refers to the German satellite mission that, during six years, collected the precise planetary-wide elevation data that is the bedrock of this atlas. To be clear, this book was obviously not the reason these satellites were put in orbit. But, once gathered, such data can have many uses and scientists can apply to get access to it, which is exactly what these three authors did.

Next to introducing the satellite mission and the principles behind radar remote sensing (specifically synthetic aperture radar interferometry), the six chapters in the 33-page introductory section provide very readable overviews of asteroid and comet formation, a blow-by-blow analysis of the first seconds and minutes following a typical hypervelocity impact, and the geological traces these leave. This last one is a  particularly important chapter. After all, how do you determine if a crater resulted from volcanism, tectonics, or an impact? Especially when you keep in mind that ancient craters are modified over time by erosion, sediment deposition, and tectonic deformation. The answer is that the forces unleashed by an impact are unlike any other geological process on our planet and modify rocks in a unique way, something known as shock metamorphism. Thus, features such as shatter cones, microscopic planar and feather fractures, and specific lithologies—impact breccias, impact melt rock, and (micro)tektites—are important diagnostic criteria.

The atlas forms the bulk of this book. Volume 1 covers Africa, North & Central America, and South America, while volume 2 deals with Asia, Australia, and Europe. It seems no impact structures have been located in Antarctica yet. The authors draw on the widely respected and accepted Earth Impact Database, hosted and maintained by the Planetary and Space Science Center at the University of New Brunswick in Canada. This contains 190 structures to which the authors add another 18 recent ones that are confirmed according to shock metamorphism criteria.

“[T]he descriptions are as revealing as the maps themselves. Many of these structures are either eroded beyond obvious recognition or were buried following impact.”

Each entry contains a full-page topographical map, coloured to show elevation, with a legend detailing longitude and latitude, the structure’s diameter, and the currently accepted age estimate. For craters that are clearly visible on the surface, additional satellite imagery is included, while for those that have been well researched the authors include geological maps or cross-sections (redrawn from earlier publications), field photos of characteristic rock outcrops, or photos of diagnostic rock samples showing traces of shock metamorphism.

Short fact sheets, written by either Kenkmann or Reimold, detail the geological setting of the impact location, the topology and age of the crater as far as known, and the history of its discovery. A short separate section gives tips on how to reach the location, ranging from “take exit so-and-so” to “requires permits / extensive expedition planning / a helicopter”. Finally, there is a list of selected references that are a goldmine in themselves, pointing to non-English publications, proceedings, and unpublished master’s theses. Mercifully, these are also compiled at the end of volume 2 in one large bibliography, together with a six-page glossary, lists of chemical elements and abbreviations, and two separate indices, one cartographic and one general. The geologic timescale is included at the end of each volume. This is thus a fully self-contained reference work.

Next to famous impact structures such as Meteor Crater or Chicxulub, there are those treated in e.g. Springer’s Impact Studies series; Virginia’s Chesapeake Bay, Russia’s Puchezh–Katunki, or Norway’s awesomely named Mjølnir. But the majority will be little known outside the impact geology research community. This is where the descriptions are as revealing as the maps themselves. Many of these structures are either eroded beyond obvious recognition or were buried following impact, leaving no visible traces at the surface. Some were revealed when aerial surveys showed magnetic or gravitational anomalies, while others were discovered by companies prospecting for minerals or hydrocarbons. Further fascinating insights are the now obsolete history of explaining these structures in a uniformitarian framework as the result of cryptovolcanism or cryptoexplosions, rather than accepting catastrophist explanations. The authors are particularly mindful to highlight the rationale behind disagreements on age or size estimates. Their rigour also shows in their decision to relegate some structures, widely accepted in the community but still in need of further work to close the case, to a separate “further confirmation required” section at the end of each continent’s chapter.

“I am very pleased the authors worked with a publisher who cares about quality. [This] is a beautiful work consisting of two over-sized volumes produced by traditional offset printing”

It would be tempting to call this work unprecedented, and it is certainly a step up from Paul Hodge’s 1994 Meteorite Craters and Impact Structures of the Earth that contained 139 entries. But there is one potential fly in the ointment: the publication last year by Springer of the Encyclopedic Atlas of Terrestrial Impact Craters that draws on the same Earth Impact Database. That atlas is based on the Italian COSMO–SkyMed mission, which also used synthetic aperture radar operating in the X-band. From what I can deduce, though, that mission did not rely on an interferometry setup with two satellites flying in tandem and did not yield elevational data.

Not having read it, I cannot speak for the quality of the scholarship of that book, though I can speak for the print quality. In my daytime job, I handle Springer books on an almost daily basis and, like the vast majority of their publications, this is a print-on-demand book. Their printing process is wholly unsatisfactory for visual books such as atlases, resulting in desaturated and grainy colour images (pretty much as if they were printed on your home inkjet printer). I am very pleased, therefore, that the authors of the book under review worked with a publisher who cares about quality. Terrestrial Impact Structures is a beautiful work consisting of two over-sized volumes measuring 24.5 × 32.6 cm in a very handsome slipcase, produced by traditional offset printing on thick, slightly glossy, high-quality paper stock. And all that at a lower price. In case you were in doubt which to choose, this, here, is the book to go for.

Terrestrial Impact Structures is a feast for the eyes that is a mandatory reference work for any professional or amateur geology or astronomy library. If you are on the fence, I will let you in on one last detail. The acknowledgements mention that the printing costs were in part covered by two of the authors. I might be proven wrong, but I have a suspicion that once this book sells out, it will not be reprinted and will quickly become highly sought after.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Terrestrial Impact Structures (2-Volume Set)

Other recommended books mentioned in this review:

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We all have a pretty good idea of what a volcanic eruption looks like, but they are only the surface expression of a much larger and longer underground process that is hidden from view. The internal workings of a volcano, its plumbing if you will, are studied by the relatively new scientific discipline of volcanotectonics. Icelandic volcanologist Agust Gudmundsson has been researching and teaching this topic for two decades and here delivers the field’s first textbook. In preparation, I beefed up my knowledge base by first reviewing a introductory volcanology textbook, but it almost was not necessary—Volcanotectonics turned out to be exceptionally instructive and accessible.

Volcanotectonics: Understanding the Structure, Deformation and Dynamics of Volcanoes, written by Agust Gudmundsson, published by Cambridge University Press in April 2020 (hardback, 586 pages)

As an academic field, volcanotectonics draws on the disciplines of structural geology, tectonics, geophysics, and, more generally, classical physics, specifically rock-, fracture-, and fluid mechanics. In the field, it draws on studies of rock outcrops, geodesy (the study of the shape of the earth and its gravitational field, here specifically the monitoring of ground deformation), and, importantly, seismology (the study of earthquakes). Additionally, there is a healthy dollop of modelling involved. That is quite the list. Plus, the book is a hefty tome of almost 600 pages. Feeling intimidated already? No need.

There are five underground structures that you will become intimately familiar with reading this book, all of them made of magma: chambers, reservoirs, dikes, sheets, and sills. The first two are, as the names imply, the underground storage parts. Reservoirs are large and deep-seated (typically 10–25 km below ground), chambers are smaller and more shallow (commonly 1–5 km below ground). The second three are the parts connecting reservoirs, chambers, and the volcanoes at the surface. Gudmundsson here uses the word dike to encompass both vertical dikes and inclined sheets. Both of these cut across rock layers. Sills, on the other hand, do not: they form where magma meets a rock layer it cannot penetrate and then spreads out laterally, parallel to it. Sills are thus emplaced horizontally, or close to it.

“Very roughly, it looks something like this: volcanoes are fed by either shallow magma chambers that are fed by deeper and larger reservoirs, or sometimes directly by reservoirs, through a complex, branching network of dikes, sheets, and sills. “

Having explained the basic anatomy, Gudmundsson proceeds with important physics concepts such as stress, strain, and elasticity, including various laws and constants to do with mechanics. It also offers one of the clearest explanations I have seen for when and why to use different modelling approaches, in this case analytical, numerical, and analogue ones. The mathematical details are purposefully kept relatively brief, with readers referred to the technical literature and books such as Rock Fractures in Geological Processes and Modeling Volcanic Processes for more details.

All this setup is a necessary warming-up exercise to understand volcanotectonic processes. Very roughly, it looks something like this: volcanoes are fed by either shallow magma chambers that are fed by deeper and larger reservoirs, or sometimes directly by reservoirs, through a complex, branching network of dikes, sheets, and sills. Many of these are dead ends: dikes can become deflected into sills if they hit rock layers they cannot penetrate and stop there (or, with luck continue upwards again if they hit on weak spots), or they can run out of steam, reaching equal pressure with their surroundings and end up as arrested dikes. Those that make it to the surface are called feeder-dikes and result in volcanic eruptions.

Gudmundsson argues that chambers originate from the rapid (geologically speaking) emplacement of sills. As long as new dikes from the reservoir at the crust–mantle boundary feed more magma into the growing sill before it cools down and solidifies, it has a chance to develop into a magma chamber, passing through an intermediate stage called a laccolith. The shape these chambers take is rarely a perfect sphere, more often a flat ellipsoid. All this subterranean movement, meanwhile, is frequently accompanied by small, local earthquakes occurring in swarms, and small but measurable ground deformation, both of which are important for monitoring and forecasting eruptions.

“What makes the book all the more convincing and attractive is that it relies on more than just theory, calculations, and modelling exercises. Gudmundsson adds results from field studies on recent eruptions and fossil volcanoes worldwide and includes numerous photos.”

For magma to force its way through the surrounding rock requires sufficient pressure to overcome local tensile strain and stress. Interestingly, the process is analogous to the artificial hydraulic fracturing, or fracking, for shale oil and gas, which has allowed the testing and confirming of ideas. Large sections of the book go into the calculations and equations you need to quantify how much pressure is needed, how this is affected by local stress and strain, and how modelling assumptions make a difference. Simplifying assumptions of a homogeneous and isotropic (i.e. uniform in all orientations) rock crust make for easy calculations but sometimes unrealistic results. In reality, our subterranean world is not quite like that: Earth’s crust is heterogeneous and anisotropic, with many layers stacked on top of each other, stiff ones alternating with softer ones. Dedicated chapters explore what this means for the often erratic paths that dikes follow as magma moves through the crust, and for the size of eruptions. Gudmundsson also outlines how particularly catastrophic eruptions (for instance Tambora, Krakatoa, and Toba) resulted from caldera collapses. Here, various dikes join up to form a ring-fault that isolates a block of rock that can subside into the magma chamber, squeezing it largely empty in the process. A final chapter applies the material to forecasting and (possibly maybe) prevention of eruptions.

There are obviously many more subtleties and complexities to it than this brief sketch, and I learned an incredible amount, suggesting that some of the unknowns Ellen Prager highlighted in her book Dangerous Earth are being filled in. What makes the book all the more convincing and attractive is that it relies on more than just theory, calculations, and modelling exercises. Gudmundsson adds results from field studies on recent eruptions and fossil volcanoes worldwide and includes numerous photos. Dikes and solidified chambers, now called plutons, come to the surface over the long stretch of time due to erosion, while quarries and road-cuts offer another window into the underground.

“The real selling points of Volcanotectonics are its superb structure and accessibility. […] earth science students […] can pick this up without trepidation”

The real selling points of Volcanotectonics are its superb structure and accessibility. Clearly formulated aims start each chapter, while summaries and lists of all the symbols used end each one. Student exercises are accompanied by worked examples that go through equations stepwise and explain symbols and units. Some degree of repetition and cross-referencing between chapters ensures important concepts are reiterated. Mathematical operators you are unlikely to have seen before are extensively introduced. And jargon is consistently and repeatedly explained. For example, the fact that strike- and dip-dimensions of dikes correspond (roughly) with their horizontal and vertical dimensions. By constantly repeating this, I noticed that halfway through the book I had absorbed their meaning. Repetition works. Arguably the only thing that students might miss is a glossary.

The result is that even someone like myself (a biologist interested in geology), whose reading on the subject is limited to an undergraduate geology textbook and introductory graduate texts on structural geology and volcanology, never felt out of my depth. Volcanotectonics should be a hit with earth science students and they can pick this up without trepidation—Gudmundsson’s many years as a teacher shine through. Significant questions and challenges remain, for example regarding submarine volcanism near mid-ocean ridges, but Volcanotectonics brings together a vast body of work and represents a significant advancement in our understanding.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Volcanotectonics

Other recommended books mentioned in this review:

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Volcanoes are some of the most awe-inspiring natural spectacles on our planet. There is much more to them, though, than the stereotypical image of a conical fire-spitting mountain, and I have been keen to learn more. As I searched for serious introductory books on volcanology, this was one title that kept coming up. But wait, why is a biologist reviewing geology textbooks?

Volcanoes, written by the late Peter Francis and Clive Oppenheimer, published by Oxford University Press in December 2003 (paperback, 521 pages)

A short preamble seems in place. My choice to study biology went at the expense of geology, although the latter topic continued to fascinate me. Two decades later, my job exposes me to many fascinating-sounding but advanced-level earth science books. I have since started to make inroads into this field for the sheer joy of expanding my knowledge. And thus I found myself eyeing up the new book Volcanotectonics. Yet, as I recently rediscovered, there is still a gap between having covered the essentials of geology and diving headlong into an advanced topic. Hoping to bridge that gap, I turned to Francis & Oppenheimer’s Volcanoes.

The first edition of this book was published in 1993 and authored by volcanology professor Peter Francis. When he passed away in 1999, his former PhD student Clive Oppenheimer, now a professor of volcanology in his own right, took it upon him to revise the text and bring it up to date for this second edition, published in 2003. Francis’s desire was to write a book to be read rather than consulted. Volcanoes is thus less of a textbook than you might think: there are no chapter summaries or student exercises. What you will find is a logical flow of chapters detailing the inner workings of volcanoes, glued together by the fascinating stories of past eruptions and, occasionally, Francis’s trademark humour, lampooning the field of volcanology.

“Volcanoes is […] less of a textbook than you might think: there are no chapter summaries or student exercises. What you will find is a logical flow of chapters detailing the inner workings of volcanoes, glued together by the fascinating stories of past eruptions […]”

Volcanoes starts with very primordial questions. Where do the heat and the rocks that drive volcanism come from? This introduces you to planetary formation and the radioactive decay of isotopes. In case you were expecting to start with plate tectonics, that is the next subject to be tackled. This explains the difference between volcanoes at plate margins where the oceanic crust is either formed or destroyed, and the minority occurring far from margins, such as the volcanic islands of Hawai’i.

Chapters four to twelve form, to my mind, the nuts-and-bolts section of this book, going into all the glorious and gory details of an eruption from beginning to end. This covers everything from formation and movement of magma; different eruption styles; types of lava; eruption columns and the deposits of ash and pyroclastic rocks they leave behind; pyroclastic density currents, debris avalanches, and mudflows or lahars—and their deposits; the different landscape forms left after eruptions, including types of volcanoes and how they erode, and the landscape depressions known as calderas; super-eruptions; and, finally, the common but hard-to-observe phenomenon of underwater volcanism.

The last four chapters cover closely allied topics: volcanoes in the solar system; the effects of recent eruptions on climate and the palaeoclimatological evidence of older ones; and, new to this edition, two chapters on monitoring of volcanoes, and assessing and managing the risks they pose.

“I was fascinated by some of the technicalities. For example by […] the physics behind eruption columns and the interplay with the wind, and how to deduce eruption intensity from them […]”

Two aspects, I thought, make this book very enjoyable to read. First, it broaches subjects without overwhelming you. When it talks of magma, it mentions the physics of gas bubble formation and growth (vesiculation), and the flow of liquid rock (rheology) without smothering you in detail. It will list different eruption styles (Hawaiian, Strombolian, Vulcanian, Plinian, etc.) and lavas (andesitic, dacitic, rhyolitic, etc.) while highlighting the arbitrary nature of such classifications, as these things exist on a continuum. And where formulas are given, for instance in the chapter on eruption columns, it is to demonstrate principles rather than go deep into the mathematics. If you are so inclined, each chapter comes with recommended sources and literature references for further research.

The authors explain terminology as they go, supported by many photos and diagrams. I would have liked a glossary—lacking that, I occasionally had to grab my dictionary to jog my mind. Even so, I was fascinated by some of the technicalities. For example by the distinction between central vent and large-scale fissure eruptions. By the underground movement of magma and intrusion of dikes. By the physics behind eruption columns and the interplay with the wind, and how to deduce eruption intensity from them. By the detective work that uses palaeoenvironmental records such as tree rings, and the extent and thickness of deposits to reconstruct eruptions for which there is no eyewitness testimony. Or by what makes pyroclastic density currents so terrifyingly destructive.

The second aspect that makes Volcanoes very readable is that this is not a theoretical treatise with hypothetical scenarios. Explanations are given by means of real-world examples of past eruptions. Four classic ones are introduced early on (Vesuvius, Krakatau, Mount Pelée, and Mount St. Helens), but plenty of others are recounted throughout. This includes those familiar from popular accounts (e.g. Tambora, Laki, and Toba), technical books (e.g. Pinatubo and the Soufrière Hills volcano), and those only known to volcanologists and victims (e.g. El Chichón and Nevado del Ruiz). You will learn as much about these eruptions as about what we learned from them.

“Having read the book cover to cover, there remains one important question that is difficult for me to answer. Given its publication date, how up to date is it? And is it time for a new edition?”

Having read the book cover to cover, there remains one important question that is difficult for me to answer. Given its publication date, how up to date is it? And is it time for a new edition? Technological advances and new space missions have revealed much more about extraterrestrial volcanoes—this book was published before the Opportunity and Curiosity rovers started trundling over the surface of Mars, for example. But what about volcanism here on earth? Recent eruptions have probably taught us new lessons (2010 tongue-twister Eyjafjallajökull no doubt revealing more about ash clouds), but not being a student of earth sciences, this is a hard question for me to answer. The only other more recent book I could think of was The Encyclopedia of Volcanoes, published in a second edition in 2015. But at over 1400 pages this can hardly be called an introductory textbook.

I decided to contact Clive Oppenheimer who kindly replied that there have not been any paradigmatic shifts in volcanology since then, but he did mention, in addition, the 2010 Merapi eruption, and highlighted new technology such as synchrotron radiation sources for fine-scale chemical analysis of volcanic rocks. Additionally, he pointed out Volcanoes: Global Perspectives (2022) as a recent textbook. And a third edition? It is not yet in the making, though he hopes to get around to it when time allows.

So, in sum, if you are looking for a good introductory volcanology textbook, I found this one both enjoyable and accessible. I came away feeling I understood much more about volcanoes. Bring on Volcanotectonics.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Volcanoes (2nd edition)

Other recommended books mentioned in this review:

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After I reviewed Joy McCann’s book Wild Sea I became fascinated with the three-dimensional nature of ocean currents. She captivated my imagination with her vivid description of the formation of bodies of heavy, cold water plunging into the abyss around Antarctica. So when Cambridge University Press announced this textbook it seemed like the perfect opportunity to dive deeper into this topic.

Ocean Circulation in Three Dimensions, written by Barry A. Klinger and Thomas W.N. Haine, published by Cambridge University Press in March 2019 (hardback, 470 pages)

Both authors are oceanographers that actively teach courses on ocean circulation, so the material and exercises presented here have been field-tested on undergraduate students. Their preface contains suggestions for teachers on how to build a two-semester course out of this book, while a useful table indicates which chapters to read before others. This thoughtful level of organisation characterises the book as a whole. The three dimensions of ocean circulation are also applied figuratively, with each chapter divided into three sections: observations of ocean movements, concepts to explain these observations, and theory to quantify and apply these concepts.

The first two chapters review the foundations of physical oceanography you need to be familiar with, of which three pillars stand out. First are the physical characteristics of the ocean, specifically the importance of temperature and salinity, but also the influence of Earth’s rotation, which affects ocean circulation through the Coriolis force. Second is how oceanographers gather their data: via submerged sensors attached to stationary or moving platforms, or via satellites. With so much of oceanography now done using computers and remotely collected data sets, it is easy to forget where your data come from. It is equally easy to forget their limitations, which feeds into the third foundational pillar: mathematical models.

The oceans are enormous and largely inaccessible, and datasets are often limited in either time or space. You can collect long time series in one location, or you can cover more ground but only collect snapshots. Satellites and remote sensing have advanced the field tremendously, but these time series are relatively recent, often have some limitation on spatial resolution or on how deep they can probe the ocean, and are of limited duration: satellites only last so long and new space missions require continued funding. As such, physical oceanography, and therefore this book, rely heavily on numerical models to fill in the gaps and make predictions.

“A useful table indicates which chapters to read before others. This thoughtful level of organisation characterises the book as a whole […] with each chapter divided into three sections”

Having explained these basics, Klinger & Haine first consider the upper ocean, then the deep ocean, and finally the unique circulation patterns at the planet’s poles. What these chapters reveal is the beautiful complexity and diversity of circulation mechanisms. I will attempt a brief summary – with advance apologies if I oversimplify or butcher concepts given my limited background knowledge.

So, at the surface, wind drives the formation of gyres (frequently mentioned in news reports on plastic pollution and oceanic garbage patches). But rather than centrally located whirlpools, the Earth’s rotation causes them to be offset to the west, leading to powerful western boundary currents hugging the coasts of various continents. The constant churning of wind and waves turns the top layer of the ocean into a mixed layer with a relatively uniform vertical profile of temperature, salinity, and density. Gyre circulation at depth differs from the surface. As you descend, pressure rises and circulation patterns slow down and weaken, building up vertical shear. At the equator, currents differ again, with converging and diverging surface flows dominating, leading to upwelling and downwelling through so-called Ekman suction and pumping, transporting water vertically. Here, the three-dimensional character of ocean circulation comes to the fore, with surface and subsurface waters flowing in different directions.

An interlude, chapter 7, talks about meanders, eddies, and small-scale mixing processes. The authors then complete the circulation picture by looking at polar overturning cells where water sinks into the abyss, moves at depth over long distances, and wells up again near the equator. This is where the topography of the ocean bottom comes into play, with sills and marginal seas having an influence. Because of the position of the continents, the world’s oceans have several north-south corridors such as the Atlantic, where the direction of flow is along lines of longitude or meridians, hence this is called meridional overturning.

“The oceans are enormous and largely inaccessible, and datasets are often limited in either time or space. […] As such, physical oceanography, and therefore this book, rely heavily on numerical models […]”

The planet’s poles deserve special attention. The main reason is that the South Pole with its raging Antarctic Circumpolar Current connects to and interacts with all of Earth’s major ocean basins. This involves all the processes discussed so far. Together with the difficulty of gathering data here, this is still aqua incognita, so to speak: many questions remain and many details are sketchy. The other reason why the poles deserve attention is that they are, well, polar opposites. While the South Pole is an isolated landmass surrounded by water, the North Pole is a land-locked ocean partially covered with sea ice. Narrow passages such as the Bering Strait and the Barents Sea Opening are the only connection to global ocean circulation.

I found the observation and concept sections of each chapter reasonably accessible, and some of the illustrations particularly helpful, though I would have liked a glossary. Klinger & Haine define important terms, but I had to go back repeatedly to look up basic concepts such as geostrophic flow that remained abstract to me. As far as the book’s level is concerned then, this is an advanced-level text – personally, I would have benefitted from first reading an introductory oceanography textbook. Students will want to tackle this book in a classroom setting, especially once it gets to the theoretical sections. I read through these only to discover mathematical operators that I didn’t even know existed. One of the endorsements printed on the book mentions the option of self-study, though my impression is that this is the preserve of advanced students and professional oceanographers who are both familiar and comfortable with the mathematics and modelling used here.

“The planet’s poles deserve special attention […] the Southern Pole with its raging Antarctic Circumpolar Current connects to and interacts with all of Earth’s major ocean basins.”

The above is, of course, not a criticism of the book, but is good to know going in. Minor suggestions for improvements would be aforementioned glossary. Similarly, an online module with animations to help visualise movements and dynamic processes (such as was included with the CUP textbook Structural Geology) would be nifty, though I recognize the time, skill, and effort involved in creating these. No, what I really felt was missing was a final integrative chapter bringing together all the concepts that have been treated separately up to that point. Clearly, different modes of circulation dominate in different parts of the oceans, and at different times, but none of them occurs in isolation. So, what, ultimately, does ocean circulation in three dimensions look like? A short ocean-by-ocean walkthrough would have been instructive. That said, I certainly would not suggest ditching the current last chapter. Here, Klinger & Haine briefly explore the link between ocean circulation and the global climate, palaeoclimatology, and the possibility of abrupt climate change.

Ocean Circulation in Three Dimensions is one of the first books I know of to tackle this topic head-on. The authors explore competing models and explanations and are mindful to highlight that this is forever work-in-progress. Nevertheless, as an overview of our current state of knowledge, this book will be a valuable reference work for professionals. Similarly, the book’s structure and plentiful exercises make it a useful textbook for students, though they will probably need a classroom or graduate course setting to get the most out of it.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Ocean Circulation in Three Dimensions hardback or ebook

Other recommended books mentioned in this review:

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Did life arise merely by accident? Many scientists feel uncomfortable with talk of goal-directedness and greater plans, as it reeks more of religion and theology than rational explanation. And with creationists lurking, the risk of “smuggling God in through the back door” under scientific pretences (as Richard Dawkins put it) is something to be wary of. Without descending into this territory, Universe in Creation might skirt dangerously close to it for some. In turns lyrical, unsettling, and, yes, speculative, this book argues that life may be written into the most basic laws of nature.

Universe in Creation: A New Understanding of the Big Bang and the Emergence of Life, written by Roy R. Gould, published by Harvard University Press in May 2018 (hardback, 273 pages)

Roy R. Gould, a Principal Investigator and Education Analyst at the Harvard-Smithsonian Center for Astrophysics, here takes a two-pronged approach to examine the emergence of life. He follows the cosmological story from the Big Bang forward, and, since life’s origin somewhere in the middle remains impenetrable, he also follows the story of evolution today back in time.

The first part was the more unfamiliar territory for me as it put forward some ideas that I had never heard of. Not being well-versed in cosmology, it is hard to be sure how widely accepted they are. Gould starts with observations by Hubble (the astronomer, not the telescope) that every galaxy in the universe is moving away from us. An expanding universe seems odd, as “gravity should attract, not repel“, writes Gould. Similarly, if the universe started with a cosmic explosion, its light should have sped off into space and be long gone. Instead, astronomers discovered that cosmic microwave background radiation, a leftover from the Big Bang, is coming at us from all directions. So, we need a new idea, and things will get more speculative going forward: “We will put aside our observations about the universe, take a deep breath, and dive into the world of ideas” (p. 42).

See, writes Gould, the terms “Big Bang” and “expanding universe” are somewhat misleading metaphors. Rather than expanding outwards into something, the universe expands inwards. How? Einstein’s model of gravity predicts that: “the universe is continuously creating more space [because] the scale of length is shrinking [with time]” (p. 61). Space is continuously welling up between the galaxies. The universe is fractalizing. This was one of those interesting and, for me, novel ideas. Gould traces its history through the 18th-century discussions between Isaac Newton and Gottfried Leibniz (is the universe the same scale everywhere?). Through the mathematician Bernhard Riemann’s questioning of a cornerstone of geometry (is the length of a line independent of its position?). And, of course, through Albert Einstein who argued that mass distorts space and time, an idea that was confirmed with the recent discovery of gravitational waves by the LIGO detector. A logical follow-up question is what happened in the beginning, allowing Gould to recount how the Big Bang theory was conceived.

“Rather than expanding outwards into something, the universe expands inwards. How? […] the universe is continuously creating more space [because] the scale of length is shrinking [with time].”

Where it gets more speculative, and for some readers perhaps questionable, is when Gould asserts that the universe has a building plan. He refers to the universe’s infrastructure: the elementary particles making up atoms, and the forces that animate them (gravity, electromagnetism, and the strong and weak nuclear forces). He marvels at the exact proportions in which these forces work: “nature’s specifications guarantee the stability of atoms” (p. 86), and remarks how slight tweaks of these values would have precluded the formation of even hydrogen atoms, and with it life.

“Why is the infrastructure of the universe so hospitable to life?“, asks Gould (p. 88), noting that this is known as the fine-tuning problem. One scientific perspective says this is a leading question and there is no reason: “nature does not “intend” to produce either atoms or life” (p. 88). A more speculative idea is that of the multiverse: “a vast landscape of universes, almost all of which would be stillborn” (p. 89). Our universe is the lucky exception where life flourished. But there is another perspective.

In 1983, physicist John Archibald Wheeler asked a question that Gould revisits throughout this book. In short: Is the universe set up such that intelligent life is guaranteed to arise? Gould thinks yes, and explores several highlights in the universe’s evolution in support. In its infancy, the universe was not completely uniform, it was just the right kind of lumpy for matter to coalesce into stars and galaxies. Had starting parameters been different this would not have happened, so “the universe was built from the start with a clever set of plans” (p. 109). Of the chemical elements forged in large stars that are scattered when stars explode, Gould writes: “it is truly marvellous that they are created in the abundances needed to form planets and to nurture life” (p. 118).

“Gould’s injection of meaning into events does not sit comfortably with me. Is the cosmos miraculously fine-tuned for life, or is life miraculously fine-tuned to the cosmos?”

This is where I found the book at its most unsettling. Gould’s injection of meaning into events does not sit comfortably with me. Is the cosmos miraculously fine-tuned for life, or is life miraculously fine-tuned to the cosmos? There is a subtle difference. Plus, we have no record of all the times life tried to take off and failed. This is a bit reminiscent of the bias that can arise when you exclude zeros and missing values during the statistical analysis of data sets.

The other half of the book looks at evolution today and works backwards. Without resorting to a veiled attempt at scientific creationism, Gould makes two arguments that life arises naturally from the laws of nature and is not just a happy coincidence. One, life’s ability to replicate depends on the molecular properties of its machinery (DNA and RNA) that are ultimately dictated by the fundamental properties of matter (what Gould earlier called the universe’s infrastructure).

Two, chance has a role to play, but random does not mean unpredictable. You can have a system with randomly behaving components that, as a whole, is still predictable. The molecular machinery of life has random behaviours (e.g. mutation and recombination) with a predictable outcome: genetic diversity. “Chance is the engine of diversity, and with enough diversity anything seems to be possible” (p. 183). This touches on some of the hottest topics in evolutionary biology such as convergent evolution, the predictability of evolution, and the origin of evolutionary innovations.

“Gould makes two [evolutionary] arguments that life arises naturally from the laws of nature and is not just a happy coincidence”

That last question touches on one of my favourite books: Andreas Wagner’s Arrival of the Fittest. Elsewhere, I rather verbosely summarised its central thesis as “evolution probing multidimensional spaces of possible protein sequences to rapidly come up with innovative solutions to life’s problems” (one day I will review that book properly, I promise). Gould, the science poet, outdoes me: “The landscape of evolutionary success appears to be very broad; there are many pathways of mutation that preserve function. Nature is wonderfully redundant.” (p. 201)

Compared to the cosmological argument in the first half of the book, I thought Gould makes a more appealing and sound argument here. Also as I consider it an example of life being fine-tuned to the cosmos rather than vice-versa. A final trio of chapters deals with senses and sensations, an exploration of the Mandelbrot set as an example of design without a designer, and the recent that might finally start offering resolutions to the Drake equation and the Fermi paradox. I was already savouring the taste of an argument well made at this point, so these chapters were like a dessert to me.

Gould is an enthusiastic and, at times, lyrical guide, and Universe in Creation is not hard to follow. It elicited contrasting responses, both fascinating and discomfiting me. That, surely, is the hallmark of an intellectually engaging book.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Universe in Creation hardback or ebook

Other recommended books mentioned in this review:

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This book is dangerous. While reading it I missed metro stops, phone calls, and sleep. I also laughed. A lot. Webcomic creator and former NASA engineer Randall Munroe returns to book form for another instalment of zany humour and absurd ideas, this time providing absurd solutions to achieving everyday tasks and solving real-world problems. From fording a river by boiling it dry using a field of 300 million electric kettles, to using a swarm of butterflies to send large data files: the solutions are purposefully ludicrous. Nevertheless, this book falls back on logical principles, giving readers both a good laugh and a gentle introduction to science, engineering, and technology.

How To: Absurd Scientific Advice for Common Real-World Problems, written by Randall Munroe, published in the UK by John Murray in September 2019 (hardback, 280 pages)

It is easy for me to assume that, surely, everyone knows xkcd. Or at least, most of my readers do. Wait, you have not heard of the stick-figure webcomic of “romance, sarcasm, math, and language“? Get with the programme already, you only have, as of the day this review was published, 2276 comics to catch up on! Started sometime in 2005 it has become one of the most popular geeky science webcomics, often consisting of only one or a few panels with stick figures. But do not let the simple drawings deceive you, the humour is clever (and the mouseover texts very much worth reading, adding an extra layer).

Munroe’s first venture into books (if we do not consider the self-published compilation xkcd, Volume 0) was What If? that offered scientifically sound explanations for unlikely scenarios. This was followed by Thing Explainer that explained complex scientific and technical concepts using only the one thousand most common English words. And now there is How To: Absurd Scientific Advice for Common Real-World Problems. In 28 chapters, the problems covered range from the seemingly mundane to the utterly absurd.

“From fording a river by boiling it dry using a field of 300 million electric kettles, to using a swarm of butterflies to send large data files: the solutions are purposefully ludicrous. “

How do you cross a river? The simple solution would be to find a shallow spot and carefully walk across that, but why do that when you can jump across it, skate over the surface, freeze it, or even boil the river away? How do you ski? Who says that skiing should be done on snow, to begin with? And what do you do when you run out of snow? On the other side of the spectrum: how do you build a lava moat? This includes proposed solutions to keeping the lava warm, your house cool, plus the costing options.

To answer his questions, Munroe seriously considers what it would actually take to make this happen, explaining engineering and physics principles by using infographics, cartoons, and equations. Want to throw a pool party in a swimming pool with walls made of cheese? Physics can tell you just how much cheese you need to prevent the pool from collapsing. After all: “Physics doesn’t care if your question is weird. It just gives you the answer, without judging.” And similarly, when considering how to move house: “I really love that we can ask physics ridiculous questions like, “What kind of gas mileage would my house get on the highway” and physics has to answer us.”

“To answer his questions, Munroe seriously considers what it would actually take to make this happen […] giving readers both a good laugh and a gentle introduction to science, engineering, and technology.”

Some of these chapters are not so much about outlandish solutions, as what solutions actually exist. When asking how to dig a hole, he explores the cost-reward trade-off when digging for treasure, and the techniques used in industry, such as vacuum excavation (this is a thing) and open-pit mining. The chapter on decorating trees, meanwhile, talks more about the largest and oldest trees in existence before digressing into which buildings would be large enough to display them in. But, by and large, the chapters stick to the book’s brief of considering the most outlandish approaches to solving real-world problems.

Particularly nice is the input from celebrities such as test pilot and astronaut Chris Hadfield (who remained unfazed by even the most unusual variations on the question of how to make an emergency crash landing) and tennis player Serena Williams (who tested how easy it is to disable a drone using tennis balls). Similarly, the inclusion of some one-page cartoons offering many answers to a problem in a graphic form break up the book nicely.

“Want to throw a pool party in a swimming pool with walls made of cheese? Physics can tell you just how much cheese you need to prevent the pool from collapsing.”

Next to a good laugh, Munroe hopes that people learn something from this book. One such “aha moment” for myself came in the chapter on how to play the piano. There is an upper limit to the frequency of ultrasonic calls used by bats, about 150 kHz. But why? You would think that as a biologist I would have an answer to this. Charles S. Cockell said it nicely in : “Because physics is life’s silent commander”, and as Munroe deftly explains, it is indeed plain old physics that gets in the way. High-frequency sounds are very quickly absorbed by the air they travel through, meaning they can only travel very limited distances before fading out. This places an upper limit on what is useful for a bat trying to catch prey by echolocation.

If you are a fan of xkcd, this book is a must-have. Munroe’s unique sense of humour works equally well for one-panel webcomics as it does for chapters running ten or more pages, and the smoothness with which he manages this transition is enviable. But beyond the xkcd fanboys and -girls, this book can be safely read by, or gifted to, anyone who enjoys geeky humour.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

How To hardback, ebook or audiobook

Other recommended books mentioned in this review:

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I guess it was inevitable that in my wider reading on subjects such as astronomy and physics I would eventually bump into quantum mechanics. Where I have encountered it so far, I have admitted it went straight over my head. It might thus seem foolhardy for a biologist to try and tackle a book like this. Then again, the hallmark of good communicators is that they make complex topics understandable. And theoretical physicist Sean Carroll’s previous books have been lauded, some even winning prizes. Are you ready to get down and dirty with quantum mechanics?

Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime, written by Sean Carroll, published in Europe by Oneworld Publications in September 2019 (hardback, 368 pages)

Carroll’s opening salvo, and one of the main reasons to write this book, is that physicists do not understand quantum mechanics. That’s right. They know how to use it to design new technology or predict the outcomes of experiments, but they do not truly understand it. And for a theory that was pretty much formulated by 1927 that is more than a bit embarrassing. What is worse, Carroll writes, is that many physicists scoff at the idea of spending time and effort on understanding its foundations.

Carroll thinks we have made good progress with this, though, and throughout this book, he champions the Everett or Many-Worlds formulation of quantum mechanics that was developed in 1957 by Hugh Everett.

This is where we reach a fork in the road. I could go ahead and try and summarize the ideas put forward in this book, leaving you with the impression that I understood everything he is talking about.

“Carroll’s opening salvo, and one of the main reasons to write this book, is that physicists do not understand quantum mechanics. That’s right.”

I could write about the contrast between classical mechanics where particles have a location and a velocity, and quantum mechanics where these are replaced by a cloud of probability. Here, particles exist in a superposition of all possible locations and velocities that only take on a single value when we observe them, i.e. quantum wave functions appear particle-like when observed. (Actually, that bit I did understand.) I could write of Werner Heisenberg’s uncertainty principle and Niels Bohr’s concept of complementarity: particles have a wave function and you can describe either a particle’s position or its momentum (its velocity), but not both simultaneously. This was empirically shown by the famous double-slit experiment.

I could write about quantum entanglement and whether or not, depending on which theorem you follow, particles interacting at a distance means that information is travelling faster than light. Or about Everett’s assertion that the universe can be described by a single wave function, evolving according to the Schrödinger equation. Or the fact that parts of the universe interacting (two particles for example) lead to them becoming entangled. That this is called decoherence and, according to Everett, means the wave function branches into multiple worlds, representing all the different ways in which such interactions could have played out. And that the space of all possible wave functions is called the Hilbert Space which may or may not have an infinite number of dimensions (I apologise in advance to any physicists reading this if I have butchered above brief summaries).

I could do all of this. But I won’t. It will probably bring a smile to Carroll’s face if I say that I would like to think that there is a branch of the wave function where I did write that review.

“[…] nature is quantum by definition – classical physics is what we observe because our brain cannot observe wave functions, the same way four-dimensional space flummoxes our brain.”

The truth is that most of the concepts explained here still seem esoteric, abstract, and counterintuitive to me. Partially that is the nature of the beast. As Carroll writes, nature is quantum by definition – classical physics is what we observe because our brain cannot observe wave functions, the same way four-dimensional space flummoxes our brain. But we can still calculate and theorise with it. And partially it reflects that even physicists are still trying to wrap their heads around all of the above.

But here are three reasons why this did not matter to me and why, despite the mental gymnastics involved, I still enjoyed this challenging book.

First, even though this book is not a history book, Carroll gives a short overview of how these ideas developed and, importantly, corrects common stories told about, for instance, Albert Einstein. Such as that by the time of the 1927 Solvay conference, where leading physicists met to discuss quantum theory, Einstein had grown old and conservative in his ideas, lost the debates with Bohr, and could not get to grips with Heisenberg’s uncertainty principle. That is not how Carroll reads this history.

“The universe does not copy itself at every interaction like a foam bath bubbling over. “Branches” and “worlds” are just convenient shorthands for us humans to talk about the evolving wave function of the universe.”

Second, in spite of the mind-bending concepts, Carroll employs excellent metaphors and examples, uses handy diagrams, and even includes a staged dialogue between a theoretical physicist daughter and her sceptical particle physicist father. And he is balanced enough to consider some alternatives to Everett’s Many-Worlds formulation. All of this makes matters if not understandable at least graspable. I found myself reading along and thinking “I sort of see where you are going with this”. Carroll’s casual writing style and occasional humour help much in this regard. And though he throws in the occasional equation as an illustration, he does not bog the reader down with impenetrable calculations.

Third and final, Carroll devotes space to providing a reality check on what quantum mechanics actually means. Over the decades, a lot of ideas have leaked into mainstream thinking where they have started leading a life of their own and are being taken out of context. Does the Many-Worlds formulation mean that there are a near-infinite number of copies of you and me out there, each corresponding to all the possible choices we could have made at every turn in our lives? Not quite. The universe does not copy itself at every interaction like a foam bath bubbling over. “Branches” and “worlds” are just convenient shorthands for us humans to talk about the evolving wave function of the universe.

Something Deeply Hidden is a book that pleasantly stretches the mind. It even makes previous books I have read, such as The Case Against Reality, a bit more understandable. Although, as an aside, my impression is that Hoffmann’s assertion of conscious agents being at the base of everything (Carroll calls it idealism on pages 223-224) is totally at loggerheads with Carroll’s understanding of quantum mechanics. Even though the finer points might still elude me (perhaps I should take it down a notch and pick up Quantum: A Guide For The Perplexed), Carroll convinces that the study of quantum foundations is a worthwhile and interesting academic pursuit. And given his pleasant writing style, I am certainly tempted by his other book, The Big Picture.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

Something Deeply Hidden paperback, hardback, ebook or audiobook

Other recommended books mentioned in this review:

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