Frank Close, Elusive (Wall Street Journal)

In July 1964, 35-year-old physicist Peter Higgs remarked, "This summer I had the only really original idea I've ever had." Forty-eight years later, Professor Higgs was in Geneva for the announcement that his idea had been experimentally verified. The Higgs boson hadn't actually been seen, but its influence on sub-atomic debris in the Large Hadron Collider was unmistakeable. And while the world's media had shown up hoping to hear from the father of the so-called God particle, Peter Higgs proved as elusive as his eponymous boson, sitting quietly in the audience, declining to comment. Friend and colleague Frank Close offers a sympathetic biography of the "shy, modest" man and famous particle, shedding most light on the complexities of the latter.

Peter Higgs' father was a sound engineer with the fledgling BBC, "uncomfortable with children." An only child, Peter was partly home-schooled on account of severe asthma and eczema. "Higgs' tendency to be a loner who would go his own way, never mind what other people think, was the product of his early years," writes Professor Close.

Largely self-taught in atomic physics, he was fascinated and appalled by the bombings of Hiroshima and Nagasaki when he was 16. While beginning his career as a university researcher he became active in the Campaign for Nuclear Disarmament, through which he met his American wife Jody. The marriage lasted until the early 1970s, the physicist "putting his scientific career before his family" when choosing between a holiday or a conference. Elusive makes no mention of any subsequent romance; the couple never divorced and "remained on good terms" until Jody's death in 2008.

Peter Higgs' scientific interest was in fundamental forces: electromagentism plus two others known as "strong" and "weak". Electromagnetic force was well explained by quantum field theory, which pictured attraction or repulsion as an exchange of massless particles - photons - able to travel across unlimited distances. The equations exhibited a property called gauge symmetry, and it was hoped that strong and weak interactions could be described in a similar way. The problem was that those forces were known to act only across sub-atomic distances, implying that their force-carrying particles had to be heavy. Theoreticians couldn't see how to model this, but in the summer of 1964, Peter Higgs found a way. Introduce a new variable in the equations - a new sort of field - and the force-carrying particles would have mass.

He presented the idea in three papers, two of which are reproduced in full in Elusive. What he didn't realise was that while working on the problem in Edinburgh, physicists in other places were independently reaching similar conclusions. A trio in London, whom he narrowly beat into print, pointed out a mistake he was able to correct. Beating them all, though, was work by two Belgians on electrical conductivity. At ordinary temperatures, electrons flowing through a cable encounter resistance. In some materials at temperatures close to absolute zero, magnetic fields shut down to short range, and electrical resistance disappears. It could be seen as a phase transition, like water turning to ice. In terms of particle physics, it's as if photons have acquired mass. Collectively, the researchers, "known by colleagues as the Gang of Six", had shown that the universe could be in a kind of frozen state. Heat things up - in a Big Bang or particle accelerator - and massive force-carriers might become massless. Forces that seemed previously distinct would become one.

Attempts to apply this idea to the strong force failed. "By the summer of 1967, Higgs gave up." Soon after, Steven Weinberg realised they "had been applying the right ideas to the wrong problem." In a short paper, he showed how to unite the weak and electromagnetic forces in a single gauge theory. He gave due credit to the Gang of Six in the reference list, but placed Higgs first, wrongly assuming he had published first. That, thinks Frank Close, is one reason why the crucial boson acquired the name it did. Unlike chemical elements or asteroids, elementary particles have no official body overseeing nomenclature. Instead, Professor Close writes, "In an utterly democratic way, particles become named by common usage." By the mid 1970s the names had crystallized: W and Z for the force-carrying bosons, and Higgs for the one making them heavy.

In 1981 an experimentalist mentioned the Higgs boson while presenting results at Brussels University and "became aware that someone in the front row was displeased." The disgruntled listener was Robert Brout, one half of the Belgian team. The speaker quickly corrected himself, saying, "I appreciate that in this work there were several people involved but as is the custom in my theoretical community I refer to it by the shortest name." Professor Brout replied, "My name has five letters."

Professors Higgs and Brout met in 1992 and "got on extremely well." By then, the W and Z particles had been confirmed at CERN, and only the Higgs boson remained to be found. With no way of predicting its mass, and hence the amount of energy required to stir it into activity, the hope lay in building ever larger particle accelerators. A vocal American advocate was Leon Lederman, whose 1993 book The God Particle made the case for the Superconducting Super Collider in Texas - cancelled that same year due to escalating costs - and introduced the notorious nickname; chosen, he wrote, because, "the publisher wouldn't let us call it the Goddamn Particle."

It brought Peter Higgs a fame he was ill prepared for. Though he had done relatively little new research since 1967, he was suddenly cast in the same light as the more media-savvy Stephen Hawking, who in 1996 made a well publicised bet that the elusive boson would never be found. Professor Higgs quietly remarked that, "Stephen Hawking doesn't know as much about particle physics as he thinks he does," and was wounded when the press gleefully reported it as a "deeply personal attack."

Equally misleading was the frequent media description of the Higgs boson as the explanation of all mass - begging the question where it gets its own from. Following its discovery in 2012, the question was who among the Gang of Six should share the Nobel Prize, which can only go to a maximum of three joint recipients. It went to Peter Higgs and the Belgian Francois Englert. Robert Brout would surely have been the third, had he not died in 2011.

Was Peter Higgs just lucky? Professor Close quotes Gary Player: "The more I practice, the luckier I become." In 1964 he worked hard for his trophy - receiving it took longer.

Sean Carroll, The Biggest Ideas in the Universe: Space, Time and Motion (Wall Street Journal)

Theoretical physicist Sean Carroll loves his subject, and dreams of a world where everyone shares his passion. "People have opinions, after all, about supply-side economics or critical race theory," he writes. "Why not inflationary cosmology and superstring theory?" The Biggest Ideas in the Universe began as a series of YouTube videos in which Professor Carroll took viewers from basic concepts such as force and energy, right up to the Higgs boson and beyond. The book version - planned as a trilogy - is intended to be equally comprehensive, written in the same pleasantly conversational style, and not shy of giving mathematical details as well as verbal explanation. By the end of this first volume, "Space, Time and Motion", you should not only understand what E = mc2 really means, but be able to write down Einstein's equation of gravity. At least, that's the theory.

The video series attracted a large and loyal following whose comments and questions became part of the ongoing material. The book version captures something of that sense of interaction, frequently addressing "you", the reader; though inevitably it's a one-sided conversation where the author's guesses of what you might be asking may not always hit the mark. Although the book is aimed at "people who have no more mathematical experience than high school algebra", I suspect that anyone without some prior knowledge of physics may be perplexed, if not by the content itself, then by the order in which it's presented. What every physics student knows is that before getting to the really interesting, exciting stuff, there are less glamorous topics that have to be mastered. "We all have memories, pleasant or otherwise, of geometry from high school," writes Professor Carroll on p174. Those with unpleasant memories might not make it that far, having been put off by the calculus and vectors of earlier chapters. A principal reason why people give up physics is aversion to mathematics, and this book offers no cure. Still, for those willing to stay the course, there are ample rewards.

What is most appealling is the combination of technical accuracy and lightness of tone. As ambitious in aim as Roger Penrose's The Road To Reality, Professor Carroll's offering is more reader-friendly, and I can imagine it being enjoyed by anyone thinking of embarking on a physics degree, or trying to fill gaps in a previous science education. This first volume takes us through the traditional pedagogic entry point of classical mechanics, into Newtonian physics with its various formulations, and on to Einstein's relativistic dynamics. The next volume will be "Quanta and Fields", then it's "Complexity and Emergence" for the finale. Why three volumes? "The trilogy format has proven successful for The Lord of the Rings and other popular franchises," Professor Carroll writes disarmingly.

The heroes of this first episode are energy and momentum. They can be altered - electricity into light, or the swing of a bat transferred to the flight of a ball - but their totals stay constant, and conservation laws of this kind play a fundamental role in physics. Professor Carroll shows how, in four dimensions, "energy is the timelike version of momentum", from which it can be deduced that energy is related to mass. Objecting to "sloppy" explanations of E=mc2 that are often given, Professor Carroll says that, "The right way to think about this famous formula is that objects have energy even if they are sitting completely at rest, and that rest energy is equal to the mass times the speed of light squared." Normally we don't see this enormous rest energy, just the tiny changes caused by motion - rather like a huge bank account that only gets used for small transactions. It's when matter gets converted to radiation in nuclear reactions - the whole account exchanged to another currency - that we appreciate how much a kilogram is worth in units of energy.

While the scientific and mathematical aspects are impeccable, the author's occasional forays into the humanities are more questionable. Early in the book, Professor Carroll mentions the mediaeval idea of "impetus" - the quality that was believed to keep moving objects in motion - and says that in the fourteenth-century Jean Buridan "proposed a mathematical formula... equating it to the weight of an object times its speed". That sounds remarkably prophetic of momentum, but we're not told where Buridan made his proposal - references are a big idea that Professor Carroll entirely neglects. I tracked down Buridan's remarks on impetus and found that what he actually proposed was quite different, likening it to heat, and saying dense substances absorbed it more readily. When philosophical statements get taken out of historical context, they risk being misinterpreted. When they're lifted second-hand from someone's webpage, the risks are greater still.

Time, one of the biggest philosophical problems imagineable, gets remarkably short shrift. "Sometimes we speak of time as some ineffably mysterious thing," Professor Carroll writes. Instead he insists that "time itself is less mysterious than we might sometimes pretend." His solution to the conundrum is that things happen in "a sequence of moments" and time is "a way of measuring the duration of some set of moments." Time doesn't flow or pass - we only think it does - and the future differs from the past because "the entropy of a closed system, including the universe as a whole, tends to increase over time." What Professor Carroll means by time is the letter t in his equations - no mystery as long as we don't think too hard about the reality it aims to represent.

Armed with an understanding of tensors and co-ordinate frames, we learn about black holes - spacetime singularities shrouded by a spherical region called the event horizon. The singularity "is not a location in space, it's a moment in time". For anything that crosses the event horizon, hitting the fatal singularity is "as inevitable as hitting tomorrow." If your spaceship wanders into a black hole, Professor Carroll warns, don't try to accelerate your way back out - it'll make tomorrow come even sooner.

Most exotic of all is the suggestion that a black hole could link separate universes by way of a "wormhole", a kink in space and time. The producers of the 2011 movie Thor needed something like that so characters could quickly traverse the cosmos in a scientifically plausible way. Desiring a more technical-sounding term than wormhole, they chose "Einstein-Rosen bridge". Professor Carroll explains it's an actual theory, though impossible in reality, only arising on paper when certain equations are "taken at face value and pushed... beyond the physical situation they were intended to describe." He adds that its appearance in Thor was "my fault" - he was science consultant on the film.