What If? Serious Scientific Answers to Absurd Hypothetical Questions

  • Randall Munroe
HOUGHTON MIFFLIN HARCOURT; 2014. 320 pp. $24

Fans of Randall Munroe's xkcd webcomic are probably already familiar with the What If? concept, where he answers hypothetical questions submitted through his website with equal parts rigour and humour. The book version brings together some classics from his website along with some brand-new puzzlers.

The questions range from whether you would need to dive to the bottom of a spent-nuclear-fuel pool to experience a fatal dose of radiation (answer: yes; you'd be fine at the surface) to what would happen if an earthquake measuring 15 on the Richter scale hit New York City (answer: things would get messy and not just in the Big Apple; according to Munroe, the Death Star triggered a magnitude 15 earthquake on Alderaan and we know that didn't end well).

There are a few chemistry-related questions in the book, including one of my all-time favourite 'what if' questions: what would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place? If we did that here on Earth, the planet's surface would, apparently, end up covered with a layer of moles 80 km deep. As Munroe delicately points out, this “smothering ocean of high-pressure meat” wouldn't be good news for the human race. If we collected a mole of moles in space instead, this would result in a mole planet just a little bit larger than our moon — and its internal dynamics would be fascinating!

The most inherently chemical question in the book considers what would happen if you built a periodic table from cube-shaped bricks, where each brick is made from the element it represents in the table. Munroe works his way through the periodic table row by row, even consulting Derek Lowe (author of the In the Pipeline blog) about the reactivity of fluorine, which is the element where things really start to get dangerous. By the time we get to transuranic bricks, the situation is somewhat apocalyptic.

Credit: COURTESY OF HOUGHTON MIFFLIN HARCOURT/RANDALL MUNROE

My one — and pretty much only — quibble is that there are a few simple chemical mistakes. Ammonia obviously isn't an element, the symbol for technetium isn't Te and “vandium” slipped past the editors too. These superficial errors are easily forgiven, however, especially when you read passages like “There's no material safety data sheet for astatine. If there were, it would just be the word 'NO' scrawled over and over in charred blood.”

There are many other questions in the book that I really enjoyed, including: if everyone on the planet stayed away from each other for a couple of weeks, wouldn't the common cold be wiped out? (answer: no); what would happen if someone's DNA suddenly vanished? (answer: it's not good); and what is the farthest one human being has ever been from every other living person (answer: it's hard to know for sure).

Many of the questions are truly absurd, but the answers are truly fascinating and are laid out step-by-step in glorious (and easy-to-follow) detail. But it's more than just that, the book is delightfully funny — not least the illustrations and the footnotes. In answering a question about how many Lego bricks it would take to build a bridge capable of carrying traffic from London to New York, Munroe uses six footnotes to discuss different styling of the word Lego — and it's utterly brilliant. Just like the book itself.