Exoplanet extravaganza

In March 2009 an article in Physics World (“Brave new worlds”) noted that scientists had discovered more than 300 planets outside our own solar system. By the end of that year, the number of confirmed exoplanets had exceeded 400; as this review is written, the tally stands at 669; by the time you read it, the number will be higher still. Such rapid progress means that any book about exoplanets will quickly become out of date, but the shelf-life of Strange New Worlds should be longer than most. The main reason is that its author, Ray Jayawardhana, is an exoplanet insider. In the late 1990s he was among the first scientists to image dusty protoplanetary discs around young, far-off stars; more recently, as an astronomer at the University of Toronto, Canada, he has written extensively about the field for a general-science readership. Jayawardhana puts all this to good use, sprinkling his book with accounts of conversations with other astronomers. In the wrong hands, this could degenerate into a clumsy citation-fest, but Jayawardhana gets the balance right: readers learn about a few of the people behind the research, but are not distracted by a new name every other sentence. It is worth remembering that the field was once considered a graveyard for promising astronomy careers. One cautionary example in the book is the US astronomer Thomas Jefferson Jackson See, who suggested in 1895 that he had discovered a planet in the 70 Ophiuchi binary system. When two others published work contradicting his claim, he wrote such a vitriolic letter of complaint to the Astrophysical Journal that its editor permanently banned him from its pages. He went on to have a nervous breakdown and finished his career as a relentless critic of Einstein’s theory of relativity. Thankfully, the current generation of exoplanet astronomers has fared better; the field underwent a complete turnabout in the mid-1990s, when a flurry of confirmed planets transformed its reputation. Strange New Worlds offers an excellent introduction to these successes, as well as insights into the field’s future.

• 2011 Princeton University Press £16.95/$24.95hb 288pp

Mathematical thoughts

Every weekday morning, the flagship news programme Today on BBC Radio 4 includes a brief segment called “Thought for the Day”, in which religious leaders from different faiths deliver mini-sermons on current events. In recent years, some secularists have demanded that the programme offer an equivalent slot to non-religious commentators. So far, the Beeb has not agreed, but should it ever do so, Göran Grimvall’s Quantify!: a Crash Course in Smart Thinking would make an excellent source for these “secular sermons”. The book is divided into about 80 short essays, loosely grouped by theme and mathematical content, and there is much fascinating material here – including an explanation of why Ohm’s law is not a law at all, and why holding the Olympics at high altitude helps triple-jumpers more than shot-putters. An emeritus professor of physics at Sweden’s Royal Institute of Technology, Grimvall is also a good writer, and his clear, gentle prose renders his book an almost effortless read. Unfortunately, the same brevity that makes his essays easy to digest also gives them an annoying tendency to end just when they seem about to shift up a gear. Grimvall’s discourse on exponentials and doubling, for example, includes a topical reference to pyramid schemes and the disgraced financier Bernard Madoff. Rather than digging into the mathematics behind Madoff’s con, however, he merely observes that “pyramid schemes are illegal in many countries, but the case of [Madoff] shows that people may never learn”. With its often frustrating lack of depth, the book actually shares one of the faults that religious critics have ascribed to “Thought for the Day”: namely, that the sermons are too short and innocuous to make much of an impact. The comparison is a harsh one, for there is much to like about Quantify! Still, we cannot help wishing that Grimvall had chosen fewer topics, and probed them a bit deeper.

• 2010 Johns Hopkins University Press £13.00/$25.00pb 232pp