As a kid, I loved Mad Magazine.  One of Mad’s features was “Snappy Answers to Stupid Questions,” which is superficially what Randall Munroe’s new book resembles.  It’s every bit as funny as I used to find Mad Magazine, but it’s snappier.  Think of it as a supremely geeked-out Mad, the kind of humor TV’s Big Bang Theory would be delivering if those writers weren’t just glossing a traditional rom-com structure with science jargon window dressing.  What If? is a book you’ll want to buy a few copies of – one for yourself, the rest for everyone you’ll give it to.

Munroe’s full title is “what if? Serious Scientific Answers to Absurd Hypothetical Questions.”  A disclaimer states, “Do not try any of this at home.  The author of this book…likes it when things catch fire or explode, which means he does not have your best interests in mind.”  In his introduction, Munroe writes, “They say there are no stupid questions.  That’s obviously wrong…But it turns out that trying to thoroughly answer a stupid question can take you to some pretty interesting places.”  Interesting is right – this is one of those addictive “Did you know?” books, whereby the reader annoys his family every thirty seconds or so with another fascinating tidbit.

The first question presented is, “What would happen if the Earth and all terrestrial objects suddenly stopped spinning, but the atmosphere retained its velocity?”  If you’re somebody whose first thought is, “That’s impossible,” this probably isn’t your kind of book.  If it piques your curiosity, read on.  Munroe answers succinctly: “Nearly everyone would die.  Then things would get interesting.”  And he spends several pages on the “interesting” part.  Munroe’s gift is to present the science accessibly – he builds his cases from examples we comprehend, and takes them to hilarious extremes.  (I was in tears laughing at his exploration of life on an asteroid like the one described in Antoine de Saint-Exupéry’s The Little Price.)

Like all great humor, What If? sneaks up on you.  Somewhere between stupid and ridiculous, Munroe usually finds a sweet spot of “aha” science.  “Human Computer,” which starts by comparing the computing power of all brains on earth to a single smartphone (answer: human brains are inferior, superior, or arguably equal to computers, depending on how you look at things) winds up illustrating the concepts behind Moore’s Law (a long-held rule-of-thumb about the ever-increasing capacity of computer processors) more clearly than other explanations I’ve seen.  Another piece starts with, “If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color?”  The short answer is “no,” but the “why” makes you re-examine what you thought you knew about our sun’s light.  And then Munroe goes beyond the “aha” to the ridiculous, wherein everyone on earth is given their own model of the single most powerful laser on Earth (the confinement beam at the National Ignition Facility, output of 500 terawatts each).  In this scenario, the moon is blasted out of orbit (because of laser ablation) and into an unpredictable solar orbit that might eventually cause it to slam into Earth.  Munroe’s punchline: “I think we can all agree that in this case, we’d deserve it.”

Put this delightful piece of brain candy on your Christmas shortlist.  Or just get it now.