Jump to ratings and reviews
Rate this book

What If? #1

What If?: Serious Scientific Answers to Absurd Hypothetical Questions

Rate this book
ASIN moved from less recent edition


From the creator of the wildly popular xkcd.com, hilarious and informative answers to important questions you probably never thought to ask.

Millions visit xkcd.com each week to read Randall Munroe's iconic webcomic. Fans ask him a lot of strange questions: How fast can you hit a speed bump, driving, and live? When (if ever) did the sun go down on the British Empire? When will Facebook contain more profiles of dead people than living? How many humans would a T Rex rampaging through New York need to eat a day?

In pursuit of answers, Munroe runs computer simulations, pores over stacks of declassified military research memos, solves differential equations and consults nuclear reactor operators. His responses are masterpieces of clarity and hilarity, complemented by comics. They often predict the complete annihilation of humankind, or at least a really big explosion.

321 pages, Kindle Edition

First published September 2, 2014

Loading interface...
Loading interface...

About the author

Randall Munroe

28 books4,900 followers
Randall Munroe, a former NASA roboticist, is the creator of the webcomic xkcd and the author of xkcd: volume 0. The International Astronomical Union recently named an asteroid after him; asteroid 4942 Munroe is big enough to cause a mass extinction if it ever hits a planet like Earth. He lives in Cambridge, Massachusetts.

Ratings & Reviews

What do you think?
Rate this book

Friends & Following

Create a free account to discover what your friends think of this book!

Community Reviews

5 stars
72,150 (43%)
4 stars
56,146 (34%)
3 stars
26,084 (15%)
2 stars
6,558 (3%)
1 star
3,278 (1%)
Displaying 1 - 30 of 10,721 reviews
Profile Image for Patrick.
Author 61 books232k followers
November 15, 2014
I've been a reader of XKCD for ages. Not just a reader, a fan. A big goey, geeky fan.

So much of a fan that when I heard about this book, I went so far as to abuse my power as an author to get an Advance Reading Copy of the book, so that I could enjoy its deliciousness sooner. And... y'know... taunt people on the internet.

And it worked. I got an early copy. And I treasured it. I petted it. It was precious to me. Precious.

Then life got in the way. Conventions. Promotion for my own book launch. I had dad stuff to do. I had prep work for the yearly Worldbuilders fundraiser. Then I had my book tour....

Through all of this, I carried my precious ARC around, waiting for the time when I'd be able to spare the brainpower to read it. I even took it on tour with me. (Honestly, this book has more frequent flier miles than any three of you put together.)

It wasn't until I got back home that I started it. I wanted something to read before I went to bed, and I picked What If because I was worried if I picked up another book I'd be reading half the night and it would screw up my already dysfunctional sleep schedule.

Despite my best intentions, I read half the book that night. It cost me precious sleep I couldn't afford to lose. But I don't regret it. Not a bit.

It's clever, but if you know anything about Randall Munroe, that won't come as a surprise to you. And it's funny, and witty (which are two different things, by the way.) But again to readers of XKCD this won't come as any sort of surprise.

The surprise was how *easy* it was to read. There's some decent science in there, but it wasn't anywhere nearly as brain-taxing as I'd expected. Munroe does a brilliant job of explaining very complex concepts simply. That's a rare gift.

The other surprise is how much it pulled me in. I expected to read the book in dribs and drabs over a couple weeks. Instead, I tore through it. That's not usually the case for me with non-fiction books.

In brief, it's worth your time. Even if you haven't read his comic. Even if you haven't ever heard of Randall Munroe. Even if you're not into science. You should pick this up and read it. You'll be glad you did.
Profile Image for Manny.
Author 29 books13.6k followers
September 16, 2014
Q: What would happen if every geek in the world received a copy of What If tomorrow morning?

A: Actually, less than you'd think.

First, a little background about this book. If you're a geek, it's unputdownable, a word that, if you think carefully, means "cannot be put down". (You may not be aware of this fact, since the word is nearly always misused). So the geek who receives it is going to carry on reading through breakfast, through lunch, while he's supposed to be working, and on through dinner, ignoring the non-geek guests who have come to visit. He'll interrupt conversations every now and then to ask things like "Could you build a bridge across the Atlantic out of Lego bricks?" or "How close would you need to be to a supernova to be killed by the neutrino flux?". He'll finish just as the last guest leaves.

There is a common myth, most likely spread by geeks, that what they do is somehow pretty important to Western civilization. If you're easily impressed by this kind of propaganda, you might expect that markets will crash as geek traders neglect their buy signals, nuclear experiments will explode as geek scientists look away from their control panels, and terrorists will strike with impunity as geek intelligence analysts fail to turn up for work. All that sounds pretty bad.

But let's stop and consider for a moment. Is any of the above geek behavior novel or unpredictable? Hardly. Geeks are always doing this kind of thing, and society has learned to work around them. Important as they may be in the long run, there's always some dependable non-geek person ready to step in just in case the geek in question has stayed up all night playing Halo or watching a Star Wars marathon. The non-geek will cover for them until the geek has got over their fifteen hour internet speed-chess session and is ready to do whatever it is they're actually being paid to do.

So delivering a copy of What If to every geek in the world will only really have two important effects. It will make a great many geeks very happy, and (assuming of course that the copies are paid for) it will turn Randall Munroe into a billionaire.

And who could possibly have anything against that?
Profile Image for Miranda Reads.
1,589 reviews155k followers
May 14, 2021

Trying to thoroughly answer a stupid question can take you to some pretty interesting places.
Randall Munroe, ex-NASA employee and author of the wildly popular webcomic XKCD, decides to look at several, undoubtedly, absurd questions and find scientific answers to them.

Nothing is too absurd for him
- whether it be the logistics of finding your soulmate to what happens if our moon suddenly disappears - Munroe answers it all.
But I’ve never seen the Icarus story as a lesson about the limitations of humans. I see it as a lesson about the limitations of wax as an adhesive.
I absolutely loved the tone of voice throughout the book.
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.
His hilarious deadpan just absolutely cinched this book for me.
It’s not the fall that kills you, it’s the sudden stop at the end.
Who knew that physics could be so fun?
Honestly, teachers need to stop the whole calculate-the-gravity-of-a-falling-ball shtick and jump on the calculate-the-force-of-wind-turbines-powered-by-people-at-a-gym bandwagon. Seriously, just make learning fun and the rest will go from there.

In short - yes! Loved this one - it was so much fun!

Audiobook Comments
I absolutely LOVED how you can just feel the enthusiasm coming from the reader. Even when he read out the math problems - you can tell that he was into it. Really made the book enjoyable!

YouTube | Blog | Instagram | Twitter | Facebook | Snapchat @miranda_reads
Profile Image for Felicia.
Author 45 books128k followers
December 20, 2016
AMAZING BOOK! I love love love it and frankly, there's no better book to read on the toilet. Off the toilet too, but I learned so much and the writing is so engaging and entertaining and just MARVELOUS. Of course in the style of xkcd, this and Atlas Obscura would be my go-to book gifts this year.
Profile Image for Valerie.
2,017 reviews164 followers
October 18, 2014
My evil plan of reading this book in small doses aloud to my students during math class has worked. Several of them have bought their own copies, and they are, I believe, planning to use their math skills for good, and not for world domination.
Profile Image for Nataliya.
743 reviews11.8k followers
May 19, 2020
“But it turns out that trying to thoroughly answer a stupid question can take you to some pretty interesting places.”

Randall Munroe of xkcd.com fame (a former physicist and NASA robotics employee turned brilliant comics artist) can come to my house for tea and in-depth discussion of hypothetical scenarios based on the world’s dumbest questions (while showing me his back-of-the-napkin math which I will blindly believe as it will just whoosh over my head like a jet plane) any time.
Dear Mr. Munroe, please consider this a standing invitation.
When I was five, I was trying to figure out how difficult it would be to reach the Moon if I were to stack chairs on top of each other (for a head start, beginning this enterprise from the roof of a 9-story building). I was sure about a 1000 would do.
I should have just contacted Randall Munroe.
“DISCLAIMER: 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 or explode, which means he does not have your best interests in mind.”
This book will provide you with detailed physics and mathematics solutions to a plethora of …ahem… interesting questions. I picked a few just to convey to you how deep the sheer awesomeness of ‘What If’ goes.

“From what height would you need to drop a steak for it to be cooked when it hit the ground?”

Munroe approaches this very important question with scientific rigor. After consulting literature on the steak drag coefficient, US military studies from the Cold War era, “research papers on the heating of ICBM nose cones as they reenter the atmosphere” and a cookbook (duh!), making an assumption that “Steaks can probably survive breaking the sound barrier”, and after making amazing graphs such as the one below …
… he finally comes to the obvious conclusion that “we should drop the steak over Pittsburgh” (because of the tradition of “Pittsburgh rare” steaks there), and our elegant answer is:
“So drop your steak from a suborbital rocket, send out a collection team to recover it, brush it off, reheat it, cut away any badly charred sections, and dig in.
Just watch out for salmonella. And the Andromeda Strain.”


“How quickly would the oceans drain if a circular portal 10 meters in radius leading into space were created at the bottom of Challenger Deep, the deepest spot in the ocean? How would the Earth change as the water was being drained?”

Some simple models clearly give you the only plausible answer: Netherlands will become a supraplanetary entity. To see how, you need to read for yourself.
“Supposing you did drain the oceans, and dumped the water on top of the Curiosity rover, how would Mars change as the water accumulated?”
Again, the answer is clear — it’s a future that will be Netherlands-shaped:


“What would happen if the Earth and all terrestrial objects suddenly stopped spinning, but the atmosphere retained its velocity?”
Brief answer: “NEARLY EVERYONE WOULD DIE. Then things would get interesting.”

“What would happen if everyone on Earth stood as close to each other as they could and jumped, everyone landing on the ground at the same instant?”
Answer: “Within weeks, Rhode Island is a graveyard of billions.”


“How fast can you hit a speed bump while driving and live?”

“Therefore, if you drove a car over a Philadelphia speed bump at 90 percent of the speed of light, in addition to destroying the city ... you could expect a speeding ticket of $1.14 billion.”


“How much Force power can Yoda output?”
“I’m going to—of course—ignore the prequels.”

After a fair share of assumptions and equations, it’s blatantly obvious that Yoda is a much better power source than Luke Skywalker. But a word of caution before we change our power grid to Yoda-based:
���So Yoda sounds like our best bet as an energy source. But with world electricity consumption pushing 2 terawatts, it would take a hundred million Yodas to meet our demands. All things considered, switching to Yoda power probably isn’t worth the trouble—though it would definitely be green.”

5 stars.

If I’m ever shipwrecked on a remote island, I hope to have this book with me — maybe somewhere in its depths there’s a calculation of how long I can last before resorting to cannibalism.
Profile Image for Paul Bryant.
2,194 reviews9,455 followers
June 11, 2016
Mr Munroe includes some “weird and worrying” questions from his website’s inbox which he presents without attempting to answer – one favourite was:

If you saved a whole life’s worth of kissing and used all that suction power on one single kiss, how much suction force would that single kiss have?

I guess the answer might be “what pharmaceutical products have you ingested during the last four hours?” or “May I speak to your parents?”

Another person named Jon Merrill asked

How fast would a human have to run in order to be cut in half at the bellybutton by a cheese-cutting wire?

Answer has to be “as fast as I will be running if I ever meet you Jon”.

And a person called Kenneth asked

What if every day, every human had a 1 per cent chance of being turned into a turkey, and every turkey had a one percent chance of being turned into a human?

Randall does not provide a response to that one but I would have said Kenneth, if only life were like that. Wouldn’t it be fabulous?

Everybody likes this book and I liked half of it, the other half was so far over my head it might have been a distant Andean condor croaking Sanskrit into a Bluetooth headset. Some of the stuff Randall devotes pages of detailed analysis to did not tickle my ivories, like

What would happen if a hair dryer with continuous power were turned on and put into an airtight 1 x 1 x 1-meter box?

I mean, get a life. Who the flook cares about a hair dryer in a box? But many are very interesting. He tackles the old chestnut

What would happen of everyone on Earth stood as close to each other as they could and jumped, everyone landing on the ground at the same time?

He picks Rhode Island (it’s just big enough for everyone on Earth, surprisingly) as a designated place where this event might be staged, and imagines the result. In regard to the jump and the landing itself, not so much would result. But then he imagines the implications of all those people trying to get back home from Rhode Island. It’s terrible – it’s an apocalypse. If this mass jumping event was actually staged it would cause the immediate termination of civilisation and the death of billions.

The edge of the crowd spreads outward into southern Massachusetts and Connecticut. Any two people who meet are unlikely to have a language in common, and almost nobody knows the area. The state becomes a chaotic patchwork of coalescing and collapsing social hierarchies. Violence is common.

Yes it is a nice book but I do not recommend that you wolf down this book as I did in 2 days, because it’s like TOO MUCH and it can get annoying. You keep thinking of your own absurd questions –

How many soldier ants would it take to chew through my leg in one hour? And would I survive?

And really, there is one question which I really want to ask Randall, it’s actually been something I have been wondering about for a long time – you know those vending machines stuffed full of really unhealthy chocs and crisps and cokes? Well, imagine a person was chained to one of those and had an infinite amount of small change within arms reach. Then imagine the vending machine gets refilled by the usual contractor in the usual way (who never notices the chained person). So : how long would it take the captive to die from a constant diet of crap? If they were only eating chocs and crisps and drinking cokes? A month? Six months? A YEAR?? It’s really bugging me. I may have to launch a practical experiment.

Profile Image for Diane.
1,080 reviews2,652 followers
November 17, 2014
This book opens with the best disclaimer I have ever seen:

"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 or explode, which means he does not have your best interests in mind. The publisher and the author disclaim responsibility for any adverse effects resulting, directly or indirectly, from information contained in this book."

That disclaimer really sets the tone for this fun book about science: Dangerous ideas ahead, folks! Don't get too close -- these things could kill ya!

Randall Munroe used to work at NASA, and now he creates the webcomic XKCD (which sounds less stressful than the NASA gig). On his website, he takes "absurd hypothetical questions" from readers and tries to answer some of them. Here are some of my favorite questions in this book:

What would happen if everyone on Earth stood as close to each other as they could and jumped, everyone landing on the ground at the same instant?

If every human somehow simply disappeared from the face of the Earth, how long would it be before the last artificial light source would go out?

How long could a nuclear submarine last in orbit?

From what height would you need to drop a steak for it to be cooked when it hit the ground?

If everyone on the planet stayed away from each other for a couple of weeks, wouldn't the common cold be wiped out?

Which US state is actually flown over the most?

Is there enough energy to move the entire current human population off-planet?

How high can a human throw something?

How fast can you hit a speed bump while driving and live?

When, if ever, will the bandwidth of the Internet surpass that of FedEx?

How quickly would the oceans drain if a circular portal 10 meters in radius leading into space were created at the bottom of Challenger Deep, the deepest spot in the ocean? How would the Earth change as the water was being drained?

How many Lego bricks would it take to build a bridge capable of carrying traffic from London to New York? Have that many Lego bricks been manufactured?

What would happen to the Earth if the Sun suddenly switched off?

If you are interested to know any of the answers to those questions, this book is for you! What made this so much fun, aside from the ridiculous questions, is Munroe's sense of humor. Several times I laughed out loud at his drawings and his answers, which is not something that usually happens when I'm reading about science. Oh, and be sure to read his footnotes, which have even more jokes.

I think this book would be a great gift for kids who love to ask crazy questions about how the world works. I think I would have loved it when I was 10.

*I need to thank my GR friend Brendon for pointing out this marvelous book, because I had never heard of the author before. It's the miracle of Goodreads!
Profile Image for Riku Sayuj.
653 reviews7,019 followers
November 23, 2014

Change.Org Petition: Despicable Munroe

The International Astronomical Union recently named an asteroid after Randall Munroe; asteroid 4942 Munroe is big enough to cause a mass extinction if it ever hits Earth.

Not that he needs an asteroid to do that. He has his minions devising millions of ways to do it, on a subversive site they call xkcd.com. This book is a set of leaked manuals.

It should be clear to all how dangerous this guy (and his site) really is. But all Government agencies fail to heed my warnings.

I exhort you to read this and then contact your local representative immediately. We can stop him. Together.

If you still have doubts, let me remind you of numerous disaster movies — there is always only ONE GUY who saw it coming! Do you really want to ignore me?

Eager for your support,

Profile Image for Philip.
973 reviews258 followers
October 9, 2014
xkcd hell - Tetris

Front Door

Youtube Comments

One of the things that's nice about goodreads is that it lets you embed pictures. ...And one of the nice things about xkcd is that it has lots of pictures licensed under CC Attribution/Non-Commerical - meaning I can post as many as I want to this review.

I'm pretty sure that if you're here, you already know about xkcd. But hey, why the heck not? Right? XKCD is why this Randall Munroe character is famous.

The book comes from his "what if" blog, which is also very good.

I took the book into work with me to show it around - you know - hipster-esque and what not. I'm reading this trendy, new book first.

But the guys at my table were all like, "Yeah... I can see myself reading like 2 or 3 of these and then putting the book down..." Everyone more or less nodded in agreement - even though they thought the book was cool.

Then I looked at the book a little bit more closely, flipped through a little bit and thought, "Huh... that sounds about right. That's probably what I'm going to do..."

I'll add that one guy in my group really hate hypothetical questions... This is mostly because kids in arguments try to prove points by using them stupidly. You know: "But what if Hitler hadn't killed the Jews? Would you like him then?" or "What if Martin Luther King Jr. had used violence? You have to admit, it's pretty crazy that we've given this guy a holiday, right?" He has a point.

So, I took the book home - slightly shamed that I hadn't realized it was more for coffee tables than actual reading.

But then I picked it up and read a couple. And a couple more. Next thing I know, a couple of days later the book is done - and I really enjoyed it. ...And I learned a lot. Well presumably.

I did come on here hoping that some of the reviews would challenge Munroe's math. Or any of his conclusions. I mean, if I did on a couple of these, there are bound to be some flame wars in the comments sections of these review right? If I could take issue with a couple... I am NOT a math guy.

In case there aren't any flame wars yet, let me start one: On page 114 in answer to the question, "If everyone on the planet stayed away from each other for a couple of weeks, wouldn't the common cold be wiped out?" he says, "The common cold is caused by a variety of viruses, but rhinoviruses are the most common culprit. These viruses take over the cells in your nose and throat and use them to produce more viruses. After a few days, your immune system notices and destroys it, but not before you infect, on average, one other person."

Then he has a footnote which reads, "Mathematically, this must be true. If the average were less than one, the virus would die out. If it were more than one, eventually everyone would have a cold all the time. But that can't be right? Can it? It's tough to tell whether he's serious or not, because sometimes the footnotes are jokes, and other times they're not.

But here, it made me question the math of the rest of the book. He's very meticulous in his calculations throughout, but here he doesn't factor in seasons, or how vast the globe is... Wouldn't it make more sense that when we have the virus we average more than one infection - and then people stay away from us - and are more cautious in general - which is why the number goes back down but doesn't die out completely?

It took me a while to get over this, undermining the whole book for a couple seconds. Seriously, if he had just said "but not before you infect, on average, on other person." I wouldn't have thought twice about it.

Of course, I doubted him on other footnotes: pg 134 "Although it'sa little different, if you drip superglue on cotton thread, it will catch fire." That can't be right can it? That's another of his jokes? Right?

Munroe also interspersed "Weird (and worrying) questions from the what if? inbox. ...Honestly, most of these weren't any weirder than the questions he was already answering. And sometimes I think they only seemed weird, but I think he may have missed the trail.

Like on page 236, the question is, "What is the probability that if I am stabbed by a knife in my torso that it won't hit anything vital and I'll live?"

There's a stick figure that says ..."Asking for a friend... former friend, I mean."

But I think it's a legitimate question. And I'm pretty sure it comes from the movie SCREAM. - wasn't it a major plot point? So, Thomas, (the person who asked the question) wherever you are - I don't think you're a weirdo. (...Yeah, yeah, yeah... spoiler alert, if you're reading this in 1996... Although, I'd be willing to wager if anyone can travel through time, it's Munroe. He's sure studying that stuff. And Einstein. And Schrodinger. Also, probably J. Robert Oppenheimer.)

And the book is so dated. He mentions the "new-fangled writing section" of the SAT on page 278. That was dropped way back in 2016. - Time travelling - am I right?

Finally, Munroe - if you're reading this - and I know you are just take the plunge and watch Dragon Ball Z already. You may hate it, but don't knock it till you've tried it, right?

Seriously - loved the book. Thought I would like it, didn't think I would love it. Didn't think I would read it the whole way through - finished it in under 3 days.

...Also, shouldn't this go under like... a sci-fi shelf? Since the questions are hypothetical... Isn't this exactly what science-fiction is? It's just not told in narrative form in this case?
Profile Image for Nandakishore Mridula.
1,242 reviews2,255 followers
July 11, 2016
An apple fell on Newton's head.

"Why didn't this fall up instead of down?" Asked the scientist...

...And lo, the theory of gravitation was born.

- Well, not really. The story is apocryphal in all probability, like George Washington and the cherry tree. But it does illustrate an important fact.

Scientific enquiry starts with seemingly absurd questions.


Randall Munroe is a physics graduate who briefly worked for NASA: but his claim to fame is as the creator of the web comic xkcd, where stick figures make fun of serious philosophical questions and scientific theories. According to Wikipedia, his site gets 70 million hits per month. And reading this book, it's not hard to see why.

Munroe reminds us that above all, science is fun.


xkcd has got an inbox where people can submit questions of any kind - and they do. The questions have to be seen to be believed. Randall Munroe takes all the questions seriously - and tries to provide "scientific" answers to each. This book is a collection of such questions and answers. The answers are sometimes tongue-in-cheek, but there is the spirit of serious scientific investigation (experiment - observation - interpretation) in each: accompanied by his signature stick figures and one-liners, they are a delight to read.

Some sample questions:

"What would happen if you tried to hit a baseball pitched at 90% the speed of light?"

"How quickly would the oceans drain if a circular portal 10 meters in radius leading into space was created at the bottom of Challenger Deep, the deepest spot in the ocean? How would the Earth change as the water is being drained?"

"Supposing you did Drain the Oceans, and dumped the water on top of the Curiosity rover, how would Mars change as the water accumulated?"

"When (if ever) did the Sun finally set on the British Empire?"

"If an asteroid was very small but supermassive, could you really live on it like the Little Prince?"

"If you suddenly began rising steadily at one foot per second, how exactly would you die? Would you freeze or suffocate first? Or something else?"

These are just a sample. There are many, many more.


If you love science, or just like asking seemingly idiotic questions just for the heck of it, or both (like me!) - this book is for you. Or you can just hop over to Munroe's site and read these - and many more - there. You can even submit an absurd question yourself.

This book is pure bliss.

("Wikipedia Protester")
Profile Image for Lindsey Rey.
286 reviews2,705 followers
July 10, 2015
I highly recommend taking the audiobook route for this one unless you absolutely love very technical science. Wil Wheaton's narration was excellent and he delivered Munroe's humor perfectly! I loved this so much I bought a hard copy for my coffee table.
Profile Image for MischaS_.
785 reviews1,340 followers
February 24, 2018
It was okay, after several "stories" it got boring. For me, it would be better just as a blog, to read "story" or two per week, not all at once.

My favourite part was the Weird (and Worrying) Questions From the What If? Inbox.

Sometimes I even felt like it had to be me who posted those questions - I believed no one had as crazy ideas/question as I do... It turns out I got a lot of soulmates out there. :D
Profile Image for Ted.
515 reviews744 followers
April 26, 2019
What if … every Goodreads review had to be written in a randomly determined time? What per cent of submitted reviews would end with a completed sentence?

Well, this amounts to the question of, what per cent of reviewers would simply stop typing when the time ran out, instead of finishing up what they were saying and ignoring the stupid rule.

But there could be a correlation (or inverse correlation?) between how reviewers reacted to such a rule, and the day job they had – or the “purity” of the field they worked in.

At any rate, let’s see …

Random time in the interval 45 minutes to 75 minutes: 53:51

I’d better turn off the baseball game. Right.

Okay, the clock is started,

Author Randall Munroe writes the on-line comic strip xkcd. (See example above.)


On the site, it’s billed as A webcomic of romance, sarcasm, math, and language. There’s a lot of casual references to computer stuff too. Munroe used to work at NASA as a physicist (I think), then decided to do this other gig. The gags he draws range from single frame, to three frames, to multiple frames extended down your computer screen – sometimes with rafts of text in table form, or anything else that he thinks appropriate for the laugh he’s aiming at.

A couple hints for looking at xkcd.
1) The humans are always drawn as stick figures. Their gender is shown by types of hairdos on the females. In the strip above, the sociologist, chemist, and mathematician are girls. Obviously.
2) By hovering your mouse over the picture (not clicking) a “bonus punch line” (my phrase) will appear. (That won't happen with the cartoon above.)


the book

The secondary title is SERIOUS SCIENTIFIC ANSWERS to Absurd Hypothetical Questions.

There might be about 60 of the Question/ANSWER articles in the book. (No time to count them.)

Interspersed with these are a dozen single page pieces called “Weird (and Worrying) Questions from the What If? Inbox”. Each page has a couple questions, with no response by the author, except for sometimes a cartoon drawing, a stick figure saying something. etc.

Here’s a quite worrying example, #6
Q. What is the total nutritional value (calories, fat, vitamins, minerals, etc.) of the average human body? – Justin Risner

Q. What temperature would a chainsaw (or other cutting implement) need to be at to instantly cauterize any injuries inflicted with it? – Sylvia Gallaher
(These are probably the worst in the book.) One of these that I wished he had answered was this one.

Q. What if every day, every human had a 1 percent chance of being turned into a turkey, and every turkey had a 1 percent chance of being turned into a human? - Kenneth

The main entries are 3-5 pages long, mostly text, some cartoons accompanying. It’s often hard to anticipate where Munroe will go with a question.

One item is called No More DNA. The question is, “This may be a bit gruesome, but … if someone’s DNA suddenly vanished, how long would that person last?”

Munroe notes that the average person would be about a third of a pound lighter, then gives a list of several ways that one can lose that amount of weight easier [more safely too!] – such as peeing.

When he gets to seriously addressing the question, he says, “To get an idea of what it might be like, lets turn to mushroom poisonings.” Specifically – the Amanita bisporigera. The several related species (from America and Europe) are called by the name destroying angel. These mushrooms contain amatoxin, which binds to an enzyme that is used to read information from DNA. “It hobbles the enzyme, effectively interrupting the process by which cells follow DNA’s instructions.” The amatoxin causes irreversible damage to whatever cells it collects in, in its case, the liver and kidney. There is a walking ghost phase of Amanita poisoning, where the person seems to get better – but their cells are accumulating irreversible and lethal damage. Munroe says this is probably similar to what might happen in the case of the absurd question being answered.

Other examples of DNA damage he talks about are from radiation and chemotherapy.

I was appropriately horrified by this piece, but I learned about a mushroom I’d never known of, that apparently can be found in the area I live in. SO I now know what it looks like, having searched it out. (Not that I eat wild mushrooms.)

Most of the questions are not this disturbing, though they are equally absurd.

How long could a nuclear submarine last in orbit?
What if everyone actually had only one soul mate, a random person somewhere in the world?
How much space does the physical internet take up?
If you call a random phone number and say “God bless you,” what are the chances that the person who answers just sneezed?

The book is like a box of assorted chocolates. You can never tell what you’ll find inside one. It might be scary, it might be funny; it might be just plain fascinating, you might learn something really strange. You very well might want to read parts of it to your partner (share the candy). Any or all, as well as other flavors not mentioned.

But the best thing about this book is to just leave it around. Pick it up and flip to a page when you have guests. Or pick it up when you have nothing better to do, and eat one of the candies again! They keep coming back, really.

00:20 I’ll quit while I’m not behind.


Previous review: It Can't Happen Here Sinclair Lewis or can lt?
Next review: The Angle of Repose lit., not science or math
Older review: Stoner John Williams

Previous library review: Science and Human Values
Next library review: The Black Swan The Impact of the Highly Improbable
Profile Image for B Schrodinger.
305 reviews658 followers
September 22, 2014
Every nerd knows Randall Munroe from his wildly humourous and insightful xkcd.com comics right?

You don't? What the hell are you doing here listening to me blab on? xkcd.com

For all those people still here, and who obviously know Randall's work, let's just bask in the mixture of intelligence, cleverness, hilarity and properly labelled axes. All the nerd girls want to sleep with him and all nerd boys want to sleep with him too...be him.

So it seems like he has been running a column on his website where people suggest extreme scientific hypotheticals and he tries to make sense of them and work out what would happen using his extreme knowledge of math and physics. I obviously have not been to observant because this book is the first I have heard of it. I guess I'm a bit of a shit fan. Hang on, I payed him for the book. Best fan ever.

The book is a collection of questions he has answered as well as questions he did not answer for the good of society as a whole. Answered questions include "If every human somehow simply disappeared from the face of the Earth, how long would it be before the last artificial light source would go out?" and "How fast can you hit a speed bump while driving and live?". These are the questions that I always ask while out in the world but I tend to forget as soon as I'm home. Or out of the shower. Definitely shower thoughts.

Questions not answered include "What is the probability that if I am stabbed by a knife in my torso that it won't hit anything vital and I'll live?" and "How fast would a human have to run in order to be cut in half at the belly button by a cheese cutting wire?" It's fun to laugh along with these, but it does make you realise that there is a fine line between scientist and horribly obscene psycho killers. Mad scientists are common in literature while Mad Florists not so much.

So this is the book for those readers who are tired of the science question and answer compendiums full of "Why is the sky blue?". I adored it and I want more.
Profile Image for Hamad.
1,009 reviews1,328 followers
November 24, 2018
This review and other non-spoilery reviews can be found @The Book Prescription

What if is a non-fiction book that -as the name implies- gives answer to some absurd hypothetical questions. The book was fun to read until at some points it wasn’t. The author is apparently a genius, I don’t know how can he think in that way. And the dedication and time that he puts to answer these questions is amazing.

I imagine the author as that student who used to sit at the front seat and answer all the questions enthusiastically.

My problem was that not all the questions were simple and even if they were or if he answered them simply, he would go and make it more and more complicated until I lost interest. Still an entertaining book, specially for the science nerds!
Profile Image for Tucker  (TuckerTheReader).
908 reviews1,596 followers
May 24, 2020
Two years after reading this for the first time, I now own two copies and re-read it monthly.
It started with a Kindle! Well, kind of. A long time ago, I bought a Kindle Fire. If you have bought a kindle Fire, then you know that Amazon fills the box with little 'tutorials'. *cough* ads in a pretty package*cough* Anyway, What If was on the pamphlet of books to read. It looked at it and thought interesting. I later read a book called 'Know it all', a book that asked and answered scientific questions. I loved it and wanted more. So I got this. It is sooo fascinating. It is full of questions that are logical yet so hard to answer. It had so many things I had been wondering myself! This is most certainly going on my Favorite shelf!

| Goodreads | Blog | Pinterest | LinkedIn | YouTube | Instagram
Profile Image for Jamie.
224 reviews117 followers
April 19, 2017
I don't think I've ever laughed this much and hard from a science or non-fiction book-wait, I take that back, I haven't laughed this much from a book period. I mean periodic tables and radioactive decay doesn't normally warrant laughter-well at least when I read about it.

The questions being presented is stuff that would have never crossed my mind, but the instant I read them I was like -oh wow-what the funk if that really happened?

I loved the illustrations throughout- and how the scientific info was made into such a fun, yet informative read. For sure checking out more stuff by Munroe.
Profile Image for Lori.
308 reviews100 followers
December 1, 2017
This is a lot of fun from a guy who likes when things catch fire.

A lot of the questions reminded me of the ones Neil Gaiman fielded after Geoff Coffey's tweet that he would donate $1 to @EFF for every person who asks @neilhimself how they can watch American Gods in their country.
Profile Image for David Rubenstein.
804 reviews2,535 followers
March 7, 2015
Randall Munroe is a dangerous guy. Seriously dangerous. He is the author of the online comic strip xkcd. It's about math, science, hacking, logic, and a host of wonderfully nerdy subjects. But in this book, Munroe answers a stack of absurd hypothetical questions. Some of the questions are really crazy, like "What would happen if everyone on Earth stood as close to each other as they could and jumped, everyone landing on the ground at the same instant?" Munroe explains that the "thud" as everyone came down at the same time wouldn't amount to much. But, the aftermath would be catastrophic.

But what's really crazy, is how Munroe takes bland questions and hypes them into incredible zingers. For example, "If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color?" The answer, of course, is "no". But Munroe never stops with an answer like that. He ups the ante, increasing the power of the laser pointers, to the point where he becomes really dangerous!

What is truly wonderful about this book, is that the answers are explained with scientific reasoning. Occasionally the answers are speculative, but this is clearly spelled out. Munroe usually applies scientific principles to answer the questions correctly, regardless of the level of absurdity. And, the questions and answers are all illustrated with his stick-figure cartoons, adding appreciably to the humor.
Profile Image for Ashley.
2,649 reviews1,690 followers
August 5, 2015
This book was equal parts hilarious and utter nightmare fuel. I have never had such an emotionally confusing reading experience. One second, snorting my drink up my nose from laughter, the next trying to shove down the sudden and complete terror I'm experiencing because I've been forced to imagine trying to survive in six atmospheres of pressure brought upon by an expanding Earth, or collapsing into a pile of human goo because I've lost my DNA, and doing so has reminded me of my mortality and oh there goes a panic attack WE'RE ALL GOING TO DIE OF LIGHTNING AND RADIATION POISONING AND THEN GET EATEN BY CATS. Unlikely potential experiences, to be sure, but that's why you don't give someone like me a book like this. Unlikely experiences are just as easy to imagine and fear irrationally and without control as likely ones, and they only stimulate the bad parts of my imagination. I am now more afraid of a global windstorm brought on by the cessation of the Earth's rotation potentially killing all life on Earth than I am of being murdered or getting a fatal disease.

All that is to say, I am most likely not this book's target audience, being a completely ridiculous ball of anxiety over things that nearly 100% will never, ever, ever happen. (I have been reading XKCD since college, though. It is a constant fixture in my life, and is not terrifying.)

As a result, it's hard to quantify my experience with this book. So let's add up the points:

+5 stars for being so smart and clever and creative
-5 stars for answering all the questions where we all die and/or the Earth is destroyed
+1 star for including the weird and worrying questions from the inbox that he refused to answer--we should know our limits, people
-1 star for being entirely too preoccupied with questions that involve danger
+1 star for my favorite question in the book, the one about calling random people on the telephone and saying "God Bless You," hoping to get someone who's just sneezed
-1 star for not having more ridiculous questions like that instead of ones where all your blood is drawn out of your finger by a ridiculously high density bullet, forming a giant blood bubble around said bullet and killing you
-1000 stars for me waiting the entire fucking book for the question involving the T-Rex being lowered into the Sarlacc pit. This question does not exist. I have been lied to.
+999 stars for the extremely obscure Kyp Durron reference that only 1 out of every 100,000 people will get (or some other number that hasn't been pulled out of my ass)
+1 star for every other Star Wars reference, all of which were clever and relevant
+1 star for the funny illustrations
+1 star for the recurring joke about the Netherlands (and the way he incorporates things like that into all his answers)
-1 star for not including in the Human Computer chapter the obvious potential scenario that the little girl was trying to lasso the cat, and the vase was knocked over in the confusion
+1 star for SCIENCE!!
-1 star for MATH :(
+1 stars for ending the book on a happy note, "Sometimes it's nice not to destroy the world for a change."
+1 star because the stars I ended up with didn't seem like enough

You can do the math for yourselves. Or, you know, look up at my star rating there.
Profile Image for Chris_P.
382 reviews250 followers
January 10, 2016
The only thing that's thought-provoking about this book is the fact that it's sold millions of copies and is considered good by the vast majority.

It bored me to death! Most (if not all) of the questions are simply useless. I mean why would I even give a fuck "what would happen if you were to gather a mole of moles in one place", or "how many unique English tweets are possible and how long it would take for the population of the world to read them out loud" (what the fuck???), or "if you call a random phone number and say god bless you, what are the chances that the person who answers just sneezed", or "what would happen if you tried to fly a normal Earth airplane in space"? This definitely isn't what I call educating. It's not even fun as a matter of fact. What's more, the answers given are absurdly complicated. Munroe in order to fill the pages, adds more useless factors making it even more boring and thus forcing you to think "why on earth am I reading this?". Honestly I haven't seen so much useless information gathered together ever before. The extra star goes for the author's occasionally witty sense of humor.
Profile Image for Darwin8u.
1,559 reviews8,686 followers
May 19, 2016
Q. What if _____?
A. Nearly Everyone Would Die!
- Randall Munroe, What If?


There are certain things on this planet that you seemed to do fine without, but as soon as you discover, you can't now do without. Diet Dr. Pepper, David Foster Wallace, dark chocolate covered cherries all fit into this category. So, too, does Randall Munroe. He seems to occupy a space near, but not on, that vacated by Gary Larson when the great Gary Larson stopped drawing the Far Side (January 1, 1995). If you are unimpressed by Gary Larsen or the Far Side or do not know who he is or what I'm talking about, hell man, read no further. This book is not for you. I'm not trying to suggest that Gary Larson and Randall Munroe occupy the same ground. They are very different. Their approach to science is different. Their technique. However, the Venn Diagram of those readers of Gary Larson 20+ years ago would closely resemble those readers of Randall Munroe's xkcd.


They are both worshiped by nerds. They are nerd gods. In this godhead of scientific nerd entertainers also exists Bill Nye. Anyway, these are binary science artists. You either get them and love them or you don't. If you don't, well congrats, I really hope someday you will recognized what you did to our beautiful world by voting for Trump. Bastard.


Anyway, this book. This book is filled with drawings and explanations by Randall Munroe on topics as diverse as:

"Q. What would happen if you tried to hit a baseball pitched at 90 percent the speed of light?"

"Q. What would happen if you were to gather a mole (unit of measurement) of moles (the small furry critter) in one place?"

"Q. How much Force power can Yoda output?"

"Q. How much Force power can Yoda output?"

"Q. How high can a human throw something?"

Here is the magic of this book, and why it is relevant and important. It is the essentials of science. Science is always jumping into absurd places asking weird questions. Monroe capture the joy of this experience and he integrates the reader into it. He is a translator (like most scientists are) of complex methods into a narrative of explanation. He just takes several absurd, but still logical steps further.

I find his book about one standard deviation better than similar attempts at similar things. I'm thinking of Leyner's books: Why Do Men Have Nipples?: Hundreds of Questions You'd Only Ask a Doctor After Your Third Martini and Why Do Men Fall Asleep After Sex? More Questions You'd Only Ask a Doctor After Your Third Whiskey Sour. Both are using humor and science and the strategy of funky questions. There are a couple differences, that matter. Mark Leyner isn't a scientist. He's a soft postmodernist author that is playing doctor explaining awkward questons. Monroe is a scientist that is using the scientific method and humor to explain absurd, and sometimes practically nonsense questions. While both of these books can be considered humor books, I tend to favor the one written by a scientist who can draw (kinda) dinosaurs and a pyramid of giraffes. Personal preference I guess.

Anyway, if you or anyone in your family is a nerd, or raising a nerd, and enjoy absurdity and funky questions, well, this is almost a perfect book. If not, go ahead and try and to convince me that your vote for Trump isn't going to be considered the beginning of the end of our civilization. You have no soul.
Profile Image for Rachelle.
334 reviews75 followers
June 14, 2021
"It's happened to all of us. You're in the belly of a vast space station and you're trying to shoot someone with a bow and arrow." -- One of many lines that literally made me lol while reading! 😂

I love these types of books, there is something wonderful about pondering a good What If! This one is interesting, witty and will make you feel smarter than when you began it.
Profile Image for Melki.
5,788 reviews2,340 followers
March 15, 2015
Please, PLEASE do not try this at home.

That warning has probably never been more applicable, as attempting to reenact many of the scenarios from this book will result in our atmosphere turning into plasma and leading to the instant ignition of the Earth's surface.

Yeah. Just what I need...one more thing to worry about.

Seriously. Please do not try making an actual Periodic Wall of Elements. A lot of those elements don't play well with others.

This book is massively entertaining and highly recommended.

There are even a few proposed experiments that DO NOT result in the destruction of our planet. My favorite involves the speed of the International Space Station AND the 1988 song by the Proclaimers, "I'm Gonna Be (500 Miles)." https://www.youtube.com/watch?v=iqq4B...

The interval between the start and the end of "I'm Gonna Be" is 3 minutes and 30 seconds, and the ISS is moving at 7.66 km/s.

That means that if an astronaut on the ISS listens to "I'm Gonna Be," in the time between the first beat of the song and the final lines . . .

Just to be the man who walked a thousand miles to fall down at your door.

. . .they will have traveled just about exactly 1000 miles.

Isn't science AWESOME?
Profile Image for منال الحسيني.
164 reviews7 followers
June 5, 2018
كتاب رائع يعرض عدد كبير من المعلومات العلمية بصورة مشوقة وجديدة من خلال أسئلة افتراضية ربما راودت اذهاننا من قبل
ل�� أرتفعنا في الفضاء بمقدار قدم واحد كل ثانية.. كيف سنموت من البرودة أم الاختناق؟"
رغم ذلك هناك عدد كبير من الأسئلة التي تبدو سخيفة أو بلا معنى
لو أجتمع كل البشر في مكن واحد قريبين من بعضهم بقدر الأمكان.. ما الذي سيحدث لو قفزوا دفعة واحدة؟
Profile Image for Becky.
1,339 reviews1,630 followers
July 19, 2015
My boyfriend has never heard of XKCD. So I'm newly single, and looking for some fun....

...book recommendations. I sure know how to live it up.

OK, OK... Part of that is untrue - I didn't dump my boyfriend for not knowing what XKCD is. He's put up with some crazy kinds of shit from me, I GUESS I can accept this from him. *sigh* I couldn't resist reading part of this out loud to him, though. But to my dismay, I don't think that he fully appreciated the genius of it, but well... some people are colorblind. Life is sometimes cruel like that.

Anyway, this book was great. I've been a fan of XKCD for a long time now, and even if this book was crap, I'd have happily purchased a copy just to support Randall Munroe for my previous webcomic enjoyment. But this book was not crap. It was great. Interesting question content, well-thought out and researched answers, just the right mixture of humor to balance out the brain 'splody math stuff... I loved it.

I'm going to give this book three awards:
First, for best comedic use of [citation needed].

Second, for best usage of footnote text EVAR. (Really, I couldn't imagine reading this in ebook format - the footnotes made me giggle so frequently that if they were a pain in the tushie to read on an ebook, so much greatness would be missed.)

Finally, for best travelogue. I've always wanted to visit The Netherlands. ;)
Profile Image for Lois Bujold.
Author 182 books37.7k followers
December 19, 2014

I grinned all the way through this, except when I guffawed.

If you know the webcomic xkcd, this needs no introduction; if you don't, 1) go find it at once (here, let me help you: http://www.xkcd.com/ ) and 2) (handwaves wildly) I don't know how to explain it. It's the only webcomic I have bookmarked. No, I don't get all the math and computer jokes either, but they do sometimes give me a glimpse into a wider world.

Highly recommended.

Ta, L.
Profile Image for Jim.
Author 7 books2,027 followers
February 10, 2017
Update: He published a lot more that aren't in this book. Read them for free here:

So... I love xkcd & some of these questions were really interesting - funny on the face with some really interesting science & math backing up the answer. For instance, the bullet being hit by lightning got into quite a few interesting facts about lightning. Who wouldn't want to know if a machine gun jet pack would work including discussions on caliber, barrel burn out, & fire rates? Cooking a steak via a high altitude drop wasn't nearly as crazy as a mole of moles, but they would make an interesting planetoid. I never would have thought of that on my own.

This isn't a book to just sit down & read. The questions & answers often require contemplation. Yoda powered houses probably won't catch on, but discovering just what his maximum power output was when he picked Luke's X-wing out of the swamp got into equations about power & how many Yodas it would take to power our civilization. Sure, I learned them in 9th grade physics, but the refresher was a whole lot more interesting than Ms. Hummel's class ever was. (Sorry, Ms. Hummel. Your class was interesting & figuring out horsepower by running up a flight of stairs was great, but... well... Yoda. Yes, I know your class was long before even the first Star Wars movie, but... Yoda-power. How green can you get?)

And then there are the Weird & Worrying Questions sections that dotted this odd amalgamation.
Would it be possible to get your teeth to such a cold temperature that they would shatter upon drinking a hot cup of coffee? is fairly horrifying, but whatever turns you on.
Is it possible to cry so much you dehydrate yourself? is sad, but they're still pure entertainment for me.

If I were Munroe & had to worry about the people sending those emails, I might well disconnect from society & move to the middle of northern Alberta, Canada. You think I exaggerate?
How many houses are burned down in the United States every year? What would be the easiest way to increase that number by a significant amount (say, at least 15%)?
How fast would a human have to run in order to be cut in half at the bellybutton by a cheese-cutting wire? Eeek! There are some scary people out there!

Highly recommended in small doses!
Displaying 1 - 30 of 10,721 reviews

Can't find what you're looking for?

Get help and learn more about the design.