The "What-If?" Book

[bachaddict]

I live in Canada and don't see any stores listed that are in Canada (at least that I know of) so how do I get a copy of What If? in Canada?

An online shop, like me (I got the ebook)

But I really want something I can hold in my hands

Then Amazon or whatever online bookstores ship to you.

[dan_dassow]

Odd juxtaposition of Amazon best sellers as of October 24, 2014:

[Normano]

I checked one of Randall's questions: "How many unique English tweets are possible? How long would it take for the population of the world to read them all out loud?" He came up with 2*10^46 tweets, which would take 10^47 seconds to read out loud. Then he explained how large a number was 10^47 seconds in terms of the rock of Svithjod.

High up in the North in the land called Svithjod, there stands a rock. It is a hundred miles high and a hundred miles wide. Once every thousand years a little bird comes to this rock to sharpen its beak. When the rock has thus been worn away, then a single day of eternity will have gone by. - Hendrik Willem Van Loon

Randall said each cube lasted 10^32 years, and 10^47 seconds was equivalent to the little bird wearing away 3,650,000 of these cubes. Multiplying 10^32 by 3,650,000 gives 3.65e38 years to read 10^47 tweets.

I don't understand that result, since 10^47 seconds is equivalent to 3.17e39 years, not 3.65e38. So if I interpreted Randall's answer properly, I think his number is almost an order of magnitude too small.

[Yakk]

The short answer? An order of magnitude is acceptable error when doing order of magnitude calculations.

How did the error happen?

It might be that 1 year is approx 10^7 seconds. It is rather close to 10^7.5 however.

The 365 is another possible clue (# of days in a year). 1 day is 60*60*24 = 86400 =~ 1e5. And 365*365=133225 =~1e5 as well.

So 365 years is about 1e10 seconds, which is an easy mnemonic.

365e32 years would be 1e42 seconds. Throw another e5 at it to hit 10^47 seconds.

365 and add 5 0s to hit how many cubes to wear out then -- 36,500,000.

But suppose instead of approximating 365 years as 1e10 we got 1e11? then we would end up with 3,650,000. How could this happen?

365 is e2.5, which rounds to e3. So 365 years = 365*365 e5 =~ e3 * e3 * e5 = e11. When doing order of magnitude calculations, your rounding can introduce errors of a factor of 10 easily.

If Randall did not remember that 365 years is about e10 seconds, and recalculated it using orders of magnitude, they could easily get things wrong by a factor of 10.

But this is naval gazing. Knowing where the error creeped in is next to impossible without looking at the work in question.

[rmsgrey]

But this is naval gazing.

Looking at ships?
</pedant>

[Mikeski]

But this is naval gazing.

Looking at ships?
</pedant>

A more popular hobby that one might expect, given Kancolle.

[Roy_K]

And now for something completely different: an error in the book. A serious one, not a typo.

UK print, p. 87: "Biking at 200 m/s would require at least 25 times the power output needed to go 40 m/s."

As a matter of fact, 125 times the power is required to overcome wind drag when speed quintuples. Why? Drag force increases with the square of speed, as Randall correctly points out. However, power is force times speed, and speed itself increases, too, doesn't it? So overall, the speed ratio has to be cubed.

Example: You can go 200 kph in a 125 bhp family sedan. To double that speed, i.e. reach 400 kph, it takes a 1.000 bhp Bugatti Veyron.

(Sorry for my unpolished English. It's not my native tongue.)

[nneonneo]

Hello, new here, got my copy not long ago. Good reads so far.

Just wanted to report two errors in the book. One is very minor: on page 148, the word "Dakotas" is misspelled as "Daktoas" (I thought it was a new species of bird or something).

The second error is a bit deeper, and involves several calculations in the "Human Computer" question. There appear to be a few flaws with the numbers. First, Hans Moravec doesn't say a human does one instruction per 90 seconds; rather, he says humans have the equivalent of 1.19e-08 MIPS (about 0.0119 IPS). The distinction is crucial: MIPS are not actually "instructions per second" in Moravec's terminology; rather, they are machine-independent computation equivalents. So it seems fishy to say that a human takes 90 seconds to execute an instruction (maybe true for division instructions, but definitely not true for data movement operations, which are some of the most common in programming). Anyway, if we assume those numbers are basically right, then the MIPS for the humans (on page 100) is still exactly 6 orders of magnitude wrong: it is stated that the low end of human capability is 0.01 MIPS, when it should be 0.00000001 (1e-8) MIPS.

On the high end, it is also a bit fishy. The footnote notes that K has 82,944 CPUs, 750M transistors each, and that it took 40 minutes to simulate 1 second of 1% of the synapses of a human brain. That's 6e13 transistors in the CPUs themselves. But now we need to figure out how many transistors would be needed to fully emulate the human brain at full speed -- i.e. K would need 40*60 times more transistors to run at real time, and 100 times more transistors to emulate the whole brain. In other words, we should need 1.5e19 transistors to emulate the human brain, which works out to 5e12 MIPS (assuming 30 transistors per IPS). The text only has 5e10 MIPS for the upper end of human capability.

Combining these two new estimates with a geometric mean yields 223 MIPS, which is a lot lower than the 30000 MIPS initially estimated by Randall. It is also much lower than the 100,000,000 MIPS estimated by Hans Moravec at hxxp://frc.ri.cmu.edu/users/hpm/book97/ch3/ (which he derived from multiplying the retina's apparent MIPS capability across the whole brain).

In terms of concrete numbers, the wrong ones are the two MIPS values at the ends of the spectrum on page 100; they should be 1e-8 and 5e12 respectively (and the transistor count should be upped to 1.5e19 from 1e15).

[bachaddict]

The What-If book is in the goodreads semifinals in non-fiction. Let's get it to the finals!

[Plasma_Wolf]

I ordered the book yesterday and the mail delivered it to me a few hours ago. Of all the things in and on the book, the most amazing one is the fact that the thing delivered to the Sarlacc is a T-Rex instead of a giant wig.

I never knew. It never occurred to me.

[Moose Anus]

the thing delivered to the Sarlacc is a T-Rex instead of a giant wig.

And now I can't unsee a wig.

Reminds me of this:

[Pelotard]

The "What If" book is selected as a prize in the New Scientist Christmas competition! (I tried to include a link but the forum thinks I'm spamming you.) This is Cool

[Paulos]

Just a few weeks ago, this book went out in Czech Republic as well Under Czech title "co kdyby?".
We even got posters for it! I found this one alongside escalators at a Prague subway station "Charles Square".

(I wanted to post a pic, but it was denied by the spam detection system...)

I've ordered one copy, and I'm sooo anxious when it gets to me. Maybe there will even be a chance to compare English original and Czech translation, as I know both languages pretty well. (I just can't really remember when to use which preposition... )

[mathmannix]

the thing delivered to the Sarlacc is a T-Rex instead of a giant wig.

And now I can't unsee a wig.

Reminds me of this:

That's awesome, but it also kinda looks like a wig.

[Envelope Generator]

Hah. I skim-read "wig" and saw that nativity picture and also did kind of see a wig. One that gives you a Larry Laffer hairline, though.

[Pfhorrest]

Watermelon, being an angiosperm, has never coexisted with tyrannosaurs, so that is clearly a nativity scene, or else a depiction of some equally fantastic fiction about non-avian dinosaurs and flowering plants coexisting.

[mathmannix]

Watermelon, being an angiosperm, has never coexisted with tyrannosaurs, so that is clearly a nativity scene, or else a depiction of some equally fantastic fiction about non-avian dinosaurs and flowering plants coexisting.

Why not both? I believe in the Nativity, and I believe in non-avian dinosaurs, flowering plants, and man all coexisting*. So, let's just call it two T. rex's worshipping the baby Jesus.

* - generally pre-flood, but some biased studies have shown that there was room on the Ark for dinosaurs, so hey, why not?

[Moose Anus]

let's just call it two T. rex's worshipping the baby Jesus.

I prefer Joseph and Mary fighting over a watermelon.

[Pfhorrest]

I will settle for two T. Rex's worshipping Baby Raptor Jesus's watermelon-shaped egg.

[azule]

I ordered the book yesterday and the mail delivered it to me a few hours ago. Of all the things in and on the book, the most amazing one is the fact that the thing delivered to the Sarlacc is a T-Rex instead of a giant wig.

I never knew. It never occurred to me.

Does it just say it's a Sarlacc and a trex or is there a story too?

[azaethral]

Reminds me of this:

It's obviously an allegorical depiction of beginnings and ends. You see the star representing the big bang and beginning of everything up in the corner, the pair of t-rex representing the great extinction of dinosaurs, the overhead structure which is a pair of side-by-side crucifixes representing the transition from BC to AD, and the nuclear bomb detonation in the center background representing the end of everything but rock and cockroaches.

Of course, it might be slightly subject to interpretation.

[david.windsor]

I live in Canada and don't see any stores listed that are in Canada (at least that I know of) so how do I get a copy of What If? in Canada?

An online shop, like me (I got the ebook)

But I really want something I can hold in my hands

Then Amazon or whatever online bookstores ship to you.

Coles/Indigo/Chapters carries it.

[Girl-With-A-Math-Fetish]

I finally got the book yesterday, and I must say it's goddamn hilarious, especially the Weird (And Worrying) questions section.
Although now I am curious what the most efficient way to increase house fires by 15% is, and how we can differentiate people with wings and wheels from airplanes. x'D

[Neil_Boekend]

The best way to increase house fires depends on your definition of best and of house fire. Assuming easiest is best and any thermal destruction of a house is a house fire and assuming you have the means then a nuclear war would do it.

We would still be able to differentiate because a human without clothes (wings and wheels or not) gets blurred on the news and a plane doesn't.

[mathmannix]

The best way to increase house fires depends on your definition of best and of house fire. Assuming easiest is best and any thermal destruction of a house is a house fire and assuming you have the means then a nuclear war would do it.

The most efficient way to start a nuclear war is probably just to royally cheese off some crackpot dictator who has a nuclear weapon, and make it obvious that you don't have one. You could make a movie about him, for example. It takes very little means, really...

[Klear]

The best way to increase house fires depends on your definition of best and of house fire. Assuming easiest is best and any thermal destruction of a house is a house fire and assuming you have the means then a nuclear war would do it.

You'd have a hard time limiting the increase to the 15% mentioned though.

[mikrit]

I've never noticed an explanation for the What-if logo, so I've always assumed it represented a question of "What might happen if you attempted to feed a T Rex to a sarlacc?" Forget the practicality of doing it, what if you did? It was great to see Randall's answer on the book jacket.

There's an answer behind that? I always thought that it was a brilliant illustration, but would not be very interesting if it was answered...

Sorry, meant the book cover; I took the dust-jacket off and found it. Where's a scanner when you need one?

Thanks for the tip! I hadn't removed the dust-jacket until now, but there was the answer. Nice easter egg for me.

EDITED to add (because double-posting is bad):
I am amazed by you people who doublecheck all calculations. About ammonia listed as an element that is easily bought in pure form: maybe Randall was thinking of an element with a similar name, perhaps antimony. But I don't know how easy it is to buy pure antimony. (Maybe you have to pay with anti-money. (Sorry, BlitzGirl.))

I bought the UK version. There is an amusing two-page preface about British units, and then most of the units are SI units (metric units) in the articles, although some feet and inches remain here and there, and the standard giraffe is used as a unit of height. That is probably a British Colonial unit.

Don't know if the metric units appear in the US version.

I enjoyed the book a lot. I was surprised that there were so many new articles.

[Neil_Boekend]

Love the explanation-like thingy of the logo.

[y5005]

Hi,

I read "What if ?" in English on the blog, and enjoy it, but for my kids, I'd like to buy the french version...

But it's still "to be announced".

Is there anyway to reach Randall Munroe to ask him when it's gonna be published ? He does not look active on Twitter...

[ubikuberalles]

I was at Kinko's (now called the FedEx Office and Printe Center) the other day waiting for them to finish up binding a book for me when I spotted the book on a shelf. On a whim I bought a copy. At the time, I didn't know why since I've pretty much read every "What If?" on the website. Still, it was nice to have it in printed form. Love the book cover with the Easter egg inside.

[Mighty Jalapeno]

Both my oldest kids have each read the book twice since February, and submitted many of their own questions.

[basementguyss]

The book's been awesome

[david.windsor]

They pull this in Canada too, using the British gallon instead of the American to make their fuel economy seem better.

No we don't, we use SI and we use a different testing method, (includes Cold weather starting, running and Hot weather running) so the same vechicle will rate lower now.

[BrianK]

And now the book is on Bill Gates summer reading list. If *that* doesn't sell Randall enough copies to go back to doing cartoons full time, then nothing will.

http://qz.com/407956/its-here-bill-gate ... ding-list/

[caduffy]

So in the "Human Computer" there is an image of an adult, a child, a broken vase and a cat.

Under which, there's a description of what happened followed by a ton of other possibilities. The generally accepted "correct" answer is not correct IMHO.

It's apparent what really happened is the kid was attempting to lasso the cat, and managed to lasso the vase instead. The cat remained to investigate, but also to gloat. Because that's something cats do.

[jonesey95]

A few more errata that I noticed:

1. I thought that the inclusion of "ammonia" in the elements answer was a joke. I guess it didn't go over that well. I laughed when I read it, anyway.

2. I noticed, somewhere, the misspelled word "activites", I believe. It should be findable by the editors with a text search. There were a couple other spelling mistakes that should be findable with a spell checker.

3. In one of the answers, the phrase "this report" appears, and it was clearly a link to something in the web version, but in the print version, there is no hypertext and no footnote, so the phrasing does not make sense.

Overall, great book. My nine-year-old and I are both What If addicts.

[kasmeneo]

I've never noticed an explanation for the What-if logo, so I've always assumed it represented a question of "What might happen if you attempted to feed a T Rex to a sarlacc?" Forget the practicality of doing it, what if you did? It was great to see Randall's answer on the book jacket.

There's an answer behind that? I always thought that it was a brilliant illustration, but would not be very interesting if it was answered...

Sorry, meant the book cover; I took the dust-jacket off and found it. Where's a scanner when you need one?

Thanks for the tip! I hadn't removed the dust-jacket until now, but there was the answer. Nice easter egg for me.

The german edition is paperback. There is no dust-jacket that could be taken off. And I didn't find the explanation anywhere else.

Apart from that... well, it's strange to read xkcd what-if in book form. The book lacks a lot of the "haptic experience" of the web site: clicking on footnotes and seeing little boxes opening, somtimes with more footnotes inside them, rolling the mouse over images to see the title text, and so on. Also having only one what-if per week or even more kind of spreads out all the information that is contained in it, while I read several book chapters a day.

But what I found strange is that the chapters are in a complete different order that they were posted on the website. For example, Relativistic Baseball (what-if #1) is at about 3/4 of the book (p273 in my edition), and Speed Bump (#61), which even has a reference to Relativistic Baseball, is a bit after the middle (p210). The reordering seems completely random to me, so why was it done?

[Feldmarshall]

The "What-if" book was made available as preorder in Polish by Czarna Owca publishing house. The publisher claims it will be released on 7th of October (in two days), and polish title is "What if? A co gdyby? Naukowe odpowiedzi na absurdalne i hipotetyczne pytania". Might be nice to update the "What-if" book page, so that polish readers would know of the translation existence.

Key-words: Polish Poland PL Czarna Owca

[sciencenerd]

It seems like a pretty cool and interesting read. Maybe I'll check it out. Thanks for posting.

[sciencenerd]

It seems like a pretty cool and interesting read. Maybe I'll check it out. Thanks for posting.