“High in the North in a land called Svithjod there is a mountain. It is a hundred miles long and a hundred miles high and once every thousand years a little bird comes to this mountain to sharpen its beak. When the mountain has thus been worn away a single day of eternity will have passed.” – Hendrik Willem van Loon

I read a lot, but it’s rare I read a book I can recommend unconditionally. This is one of them, with the extra bonus you can read a lot of it in advance online to see if you agree. It’s insightful, it’s hilarious, and best of all it can give you a glimpse into how scientists think, working through the world from first principles.

The book is exactly what the title says: it gives carefully worked out answers to absurd questions, like what would happen if you swam in a nuclear waste pond (nothing – water is great radioactive shielding. Of course, trying to swim in such a pond would get you shot by the guards), hit a baseball going at .9c (Boom!), endured a robot apocalypse (the robots would probably slip on the mountain of skulls and most can’t open doors or pass those tricky rubber thresholds on lab doors. Even most battle drones would be stuck, “helplessly bumping against hangar doors like Roombas stuck in a closet.”) or lived in a world with love at first sight (people would want to be police officers or receptionists, since they make eye contact with the most people).

Munroe was a robotics engineer at NASA, so has good science credentials. He left to run his webcomic, xkcd (which I also highly recommend). His book, however, takes columns from a series he did online, What If, and puts them in convenient book form with some additions – you should definitely read the online column first to see if it’s your thing, and I’m not sure how much new content there is, to be fair.

The book is hilarious, as you’d expect from the author of xkcd. For me, the best part is that Munroe can’t seem to avoid thinking like a physicist. Keeping in mind I started my degree in physics, I love it: it reminds me of the great way scientists have of looking at the world. Analysis like:

“First, let’s start with wild ballpark approximations… I can pick up a mole (animal) and throw it.^{[citation needed]} Anything I can throw weighs one pound. One pound is one kilogram. The number 602,214,129,000,000,000,000,000 looks about twice as long as a trillion, which means it’s about a trillion trillion. I happen to remember that a trillion trillion kilograms is how much a planet weighs.”

There is basically nothing I don’t love in that paragraph. This is how reasoning about the world should work, for oh so many reasons!