Wednesday, October 18, 2017

What If? Serious Scientific Answers to Absurd Hypothetical Questions by Randall Munroe

Source of book: Borrowed from the library

What If? Serious Scientific Answers to Absurd Hypothetical Questions is the most fun book I have read this year. It is exactly what it sounds like.

Randall Munroe is the creator of the XKCD webcomic. (In case you wondered, no, it doesn’t stand for anything.) The comic covers a pretty broad range of nerdiness, probably due to Munroe’s background at NASA. Anyway, it is pretty fun to check out from time to time.

The book has plenty of absurd questions, which fall into two categories. The first is “questions that the author actually answers.” The second is “questions which are so absurd that the author just puts the question on the page and leaves it there for mocking.” For example, “If people had wheels and could fly, how would we differentiate them from airplanes?”

Munroe tackles the questions using science - and some creative approaches. After all, many of these questions require deciding what measurement will be used, and what the end result should look like. The author’s dry humor is combined with his stick-figure comic drawings.

Since there are 300ish pages, I’ll just hit a few highlights.

First, the best absurd question in the book is this one:

Q. What if you strapped C4 to a boomerang? Could this be an effective weapon, or would it be as stupid as it sounds? ~ Chad Macziewski

  1. Aerodynamics aside, I’m curious what tactical advantage you’re expecting to gain by having the high explosive fly back at you if it misses the target.

Then, consider this bit of nerdiness. In answering a question about why self fertilization isn’t as advantageous genetically as sexual reproduction, Munroe uses Dungeons & Dragons’ character stats as his illustration of how traits are inherited - and why a bad gene is exacerbated by self fertilization (or inbreeding…)

Or, how about this one? Munroe answers a series of questions about escape velocity and reentry heat. To illustrate the speed of the International Space Station, he uses “I’m Gonna Be (500 miles)” by the Proclaimers. Which, in a fun coincidence, is just long enough so that during the duration of the song, the ISS travels...wait for it...1000 miles.

Apparently, Munroe likes music in his illustrations, as references from pop to classical are throughout the book. In one of the funniest, he compares the “ring cycle” for Sprint’s cell service (how long before it goes to voice mail) to another famous Ring Cycle.

I also can’t resist the tag to the discussion of what would happen if the earth’s size increased. The moon would eventually get pulled in too close. At the Roche limit, the gravitational forces would tear the moon apart, leaving rings. “If you liked it, then you should have moved a mass inside its Roche limit…”

Had you ever wondered what it would be like if all the precipitation in a thunderstorm was concentrated into one giant drop? Well, you can find out here. Munroe also theorizes that such a bizarre storm would eventually be known as a “dubstep storm,” because...wait for it, “It had one hell of a drop.”

The book isn’t all jokes, though. There are some really cool facts too. For example, if you wanted put a rope around the earth, then raise it one meter off the ground, how much more rope would you need? Believe it or not, only 6.28 meters. (Do the math - it works!) In the same discussion, the author notes that although small changes on this percentage scale don’t affect structures, they would completely befuddle GPS, which is so sensitive that the system has to be engineered to account for the effects of both special AND general relativity. 

Here’s one that my wife will appreciate: at the end of the discussion of where on earth a human can be the furthest away from any other human, the conclusion was that the best example was not on earth at all: it was the single astronaut left in the Command Module while the other two were on the moon. Al Worden, the Apollo 15 astronaut, actually liked the isolation. As Munroe puts it:

“Introverts understand; the loneliest human in history was just happy to have a few minutes of peace and quiet.”

Music, introversion, bad jokes, let’s see, what else? Oh yeah, cats. In the answer to a question about the Richter Scale, Munroe goes backwards, illustrating negative number magnitudes. (Since the scale is logarithmic, negative numbers are negative powers of ten…) Anyway, a magnitude -2 earthquake would be equivalent to a cat falling off a dresser. A -3 magnitude would be the cat knocking the cell phone off instead.

As a final note, here’s one for my brother. Munroe imagines that the water in earth’s oceans is siphoned off, and placed on Mars instead. To show the way the planet would look, Munroe uses a standard Mercator projection - and then talks smack in the labels. (“2 stars. Would not buy again…”)

This is a fun book, perfect as a light diversion at the end of the day. Just keep this in mind:

Do not try any of this at home. The author of this book is an Internet cartoonist, not a health or safety expert. He likes it when things catch fire and explode, which means he does not have your best interests in mind.

(Yeah, thanks, lawyers…)


Hey, sing along!


  1. I love this book. I kept it in my cupboard next to the bathroom so I could keep reading it. It is wonderful.

  2. Our family adores this book!

    But you failed to mention my favorite chapter: what happens if you build a periodic table out of the actual elements? It's awesome - I crack up every time I read it.

    1. That is a good one. There is also this:

  3. You didn't link specifically to his what-ifs and I think it's pretty easy to miss on the main site:

    I'm not sure if he has the entire book up. You also can submit your own questions, if you've something clever.

    I enjoyed his Thing Explainer book as well. He explains things using only the thousand most commonly used words.

    1. That sounds like an interesting one to find for my own collection. I'll put it next to The Way Things Work by David Macaulay. :)

    2. I got The Way Things Work as a high school graduation present. Awesome book!