A puzzle for the UK

Sadly, my current Thing Explainer book tour doesn’t stop in the UK (although you can come see me at London’s Royal Institution via live videolink on December 7th—tickets here).

However, in lieu of an in-person visit, my publisher and I have put together a special puzzle for UK readers to solve.

The puzzle has two steps. Step one is to find out where step two is.

For step one, you can pick any one of five cities. Here’s a helpful map, followed by some interesting facts about each city.


Bristol: 2.72km
A major port, built on seven very steep hills, Bristol has long been home to explorers and inventors – and the UK’s oldest dinosaur. In 1497 John Cabot sailed out of Bristol to try to find a better route to Asia and discovered Newfoundland instead. Isambard Kingdom Brunel designed this tall road in 1830. It took another 34 years to finish, and he lived only to see the towers built (one in the suburb the road is named after).

London: 0.44km
A city famous (in song) for its bridges falling down and (in stories) for its streets not being paved with gold.  A fifth of all the pieces everything is made of were discovered in London, including hydrogen (originally called ‘inflammable air’) in Clapham, and ten by Humphrey Davy here. There’s even a red world space car in the Science Museum.

Oxford: 0.51km
Inaccurately described by writers as ‘a city of dreaming spires’, Oxford is obsessed with thing explaining. Oxford professors CS Lewis, Tolkien and Lewis Carroll turned Christianity, Anglo Saxon and mathematics into successful works of fiction. This college lays claim to William of Ockham who came up with the principle of Ockham’s razor, that the most straightforward answer is usually the right one. They would all agree that the writing stick is mightier than the sword.

Edinburgh: 1.85km
Built on an extinct volcano, this city is famous for its body snatchers, for Peter Higgs (big tiny thing hitter) and for Dolly the sheep. Alexander Graham Bell was educated here, and missed it so much when he moved across the Atlantic that he invented the telephone, precursor to the hand computer.

Cambridge: 0.05km
The university was founded in 1209 by students on the run from the Oxford police. Home to Isaac Newton, famous for working out colours of light and for understanding how dangerous sitting under an apple tree could be; a descendant of that tree remains near his room.  Also home to Stephen Hawking and 89 Nobel prizewinners (31 more than Oxford), and the Mathematical bridge.

Good luck!

Prizes will include signed copies of Thing Explainer and limited-edition posters and mobiles. There will also be one very special first prize.

Those who’ve solved the clue but are unable to get there in person should get in touch at thingexplainer@johnmurrays.co.uk. For updates on the results see @johnmurrays. The results and winners will be announced on www.johnmurraybeagle.co.uk on 7th December 2015.

A Thing Explainer word checker

Want to try writing using only simple words? Here’s a writing checker you can use: xkcd.com/simplewriter.

To help me write the words in my Up Goer Five picture, I taught my computer to watch my writing and tell me when one of the words I used wasn’t in the top ten hundred. After I put up my Up Goer picture, other people made things to check writing, too (like this one).

When I decided to write Thing Explainer, I went back to the writing checker I had used and made it better. Now, I’m happy to be able to share it with everyone!

To use it, just touch here and start writing. If you use a word that’s not in Thing Explainer’s set of the ten hundred, the word will turn red. (I usually count all forms of a word, like “kick” and “kicked,” together as one word, although there are a few special cases where I don’t.)

Have fun explaining things!

A note on the words: Some words are used more often in certain kinds of writing and talking than in others, which means different ways of counting words will give different answers for which ones we use the most. The set of ten hundred words in Thing Explainer comes from putting together many ways of counting how much people use a word to come up with a single set of ten hundred words that should sound familiar and simple to lots of people. 

Thank you to James Zetlen, who helped make the word checker work on other people’s computers and not just mine.

I’m going on a book trip!

I made a book that explains things. It’s called Thing Explainer. It will be out soon! It’s a big flat book full of pictures of things with lots of parts. There are also little words that tell you what all the parts do. You can read more about it here!

When my book comes out in two months, I’m going to visit a lot of places with it! I’m going to New York, Seattle and Portland, San Francisco and Berkeley, Houston, Chicago and Naperville, and Toronto. If you live near one of those cities, maybe you can come see me!

In each city I visit, I’ll be standing in a big room and talking to people. I’ll also be writing my name in people’s books, but only if they want me to.


Here’s how you can come see me in each city. (This part doesn’t use simple words, but that’s because I like the people whose buildings I’m visiting and don’t want to make problems by using different words from the ones on their signs and stuff.)

33 E 17th Street
Note: A limited number of wristbands and seats will be available to those who provide proof of purchase of Thing Explainer from a Barnes & Noble retail location or BN.COM. For details, click here.

In Conversation with Hank Green
1119 8th Avenue
Tickets: $5 includes admission. Seating is limited. A portion of proceeds from ticket sales will be donated to Zeno: Math Powered. To purchase tickets and for details, click here.

3415 SW Cedar Hills Boulevard
Note: Book signing only. Purchase of Thing Explainer from Powell’s is required for admission. Space is limited. For details, click here.

155 Fell Street
Tickets: $35 includes one book and admission. Seating is limited. To purchase tickets and for details, click here.

First Congregational Church
2345 Channing Way
Tickets: $35 includes one book and admission. Seating is limited. To purchase tickets and for details, click here.

1601 NASA Parkway
Tickets: Free with the price of admission to Space Center Houston. Seating is limited to those who RSVP here. To purchase tickets and for more information about Space Center Houston, click here.

North Central College at Pfeiffer Hall
310 E Benton Avenue
Tickets: Free, but required for admission. Seating is limited. To get tickets and details from Anderson’s Bookshop, click here.

222 W Merchandise Mart Plaza
Tickets: $43 includes one book and admission. Seating is limited. To purchase tickets and for details, click here.

In Conversation with Ryan North
93 Charles Street W
Tickets: $40 includes one book and admission. Seating is limited. To purchase tickets and for details, click here.

Other places

Can’t make any of these events, but still want a signed copy? A limited quantity of signed Thing Explainers are available to pre-order from Harvard Bookstore, Porter Square Books, and Brookline Booksmith.

Already pre-ordered your copy? Email your proof of pre-order for the print edition of Thing Explainer—either a copy of your e-receipt or photo of print receipt—and mailing address to trademarketing@hmhco.com by November 15, 2015 and you’ll be entered to win one of 300 signed bookplates, which look like this:

TE bookplate

Winners will be chosen at random. Winners will be notified and bookplates will ship the week of November 23, 2015. (U.S. participants only—sorry!)

New book: Thing Explainer

A while ago, I posted the comic Up Goer Five, an annotated blueprint of the Saturn V rocket with all the parts described using only the thousand most common English words.

Today, I’m excited to announce that I’m publishing a collection of large-format (9″x13″) Up Goer Five-style blueprints. The book is full of detailed diagrams of interesting objects, along with explanations of what all the parts are and how they work.

The titles, labels, and descriptions are all written using only the thousand most common English words. Since this book explains things, I’ve called it Thing Explainer.


The diagrams in Thing Explainer cover all kinds of neat stuff—including computer buildings (datacenters), the flat rocks we live on (tectonic plates), the stuff you use to steer a plane (airliner cockpit controls), and the little bags of water you’re made of (cells).

Thing Explainer will be published by Houghton Mifflin Harcourt on November 24th. You can preorder it now (AmazonBarnes & Noble, Indie Bound, Hudson); click here for links to more information and options.

Or, in the spirit of the book:

I had a good time drawing Up Goer Five, so I decided to draw more pictures like that and make a book of them. The book explains things, so it’s called Thing Explainer.

You can’t have Thing Explainer yet, but if you want, you can order it now, and you’ll get it about a month before the end of the year.

Touch these blue words to learn how to get Thing Explainer.

What If book tour!

My book, What If?: Serious Scientific Answers to Absurd Hypothetical Questions, comes out September 2nd (Pre-order: Amazon, Barnes & Noble, IndieBound), and I’m excited to announce that I’ll be going on a book tour!

Here’s the event list:

Tuesday, September 2

Harvard Book Store at Brattle Theatre
40 Brattle St.
6:00pm (Seating is limited) – Note: this event is now sold out! But, you can still pre-order a signed copy (link below).
Tickets: $26 tickets on sale August 12 at 9am ET, includes one book, one seat.
More details: http://www.harvard.com/event/randall_munroe/
Pre-order a limited number of signed copies of What If? from Harvard Book Store.

Friday, September 5
Barnes & Noble – Union Square
33 E 17th St.
Open event, seating is first come first serve.
More details: http://store-locator.barnesandnoble.com/event/84245

Tuesday, September 9
Town Hall Seattle
1119 8th Ave.
Seating is limited – Note: this event is now sold out!
Tickets: $5, one seat
More details: http://www.townhallseattle.org/randall-munroe-answering-what-if/

Wednesday, September 10
The Booksmith at Public Works
161 Erie St.
Seating is limited – Note: this event is now sold out!
Tickets: $34 includes one book, general admission; $20 general admission
The bar at Public Works will be serving drinks before, during, and after the program. This event is necessarily limited to people 21 and older.
More details: http://www.brownpapertickets.com/event/772183

Thursday, September 11
Berkeley Arts & Lectures at the Hillside Club
2286 Cedar St.
Seating is limited – Note: this event is now sold out!
Tickets: $10 with student ID; $15 general admission
More details: http://www.brownpapertickets.com/event/772197

Friday, September 12
Google+ Hangout On Air moderated by Hank Green
Location: Online/Various
3:30pm PT/ 6:30pm ET
Note: Anyone can view the Hangout live on YouTube (Friday, 9/12, 3:30pm PT), but only 4-6 xkcd readers will be selected using this form  to participate and ask questions within the Hangout itself. Apply for a chance to participate in the Hangout by Monday, August 25.

Sunday, September 14
Live Talks LA
An afternoon with Randall Munroe
The Aero Theatre
1328 Montana Avenue
Santa Monica
Seating is limited
Tickets: $43 includes one book, one reserved seat; $20 general admission
More details: http://livetalksla.org/blog/2014/07/13/september-14-randall-munroe/

Hope to see you there!


Back in early March, I posted comic #1337, Hack, about a wayward spacecraft. ISEE-3/ICE was returning to fly past Earth after many decades of wandering through space. It was still operational, and could potentially be sent on a new mission, but NASA no longer had the equipment to talk to it—and announced that reconstructing the equipment would be too difficult and expensive.

ISEE-3 is just a machine, but it’s a machine we sent on an incredible journey; to have it return home to find our door closed seemed sad to me. In my comic, I imagined a group of internet space enthusiasts banding together to find a way to take control of the probe—although I figured this was just a hopeful fantasy.

I wasn’t the only one who liked the idea of “rescuing” ISEE-3. In April, Dennis Wingo and Keith Cowing put up a crowdfunding project on RocketHub to try to learn how the lost communications systems worked, reconstruct working versions of them, obtain use of a powerful enough antenna, and commandeer the spacecraft. It seemed like an awfully long shot, but I contributed anyway.

Well, yesterday, Cowing and his team announced, from the Arecibo radio telescope in Puerto Rico, that they are now in command of the ISEE-3 spacecraft.

Congratulations to the team, and good luck with your new spaceship! Watch out for hackers.

The Baby Name Wizard

The OKCupid statistics blog, by Christian Rudder, is amazing. Sadly, it hasn’t updated since 2011, around when OKCupid was bought by Match.com. (Rudder says the timing was a coincidence—he took time off for another project, and the blog may return soon!)

In the meantime, I’d like to recommend another unexpectedly engrossing blog: The Baby Name Wizard blog, by Laura Wattenberg (creator of the amazing Name Voyager graphing tool).

I find the Baby Name Wizard blog fascinating because, like the OK Cupid Blog, it combines two key ingredients:

  • Access to rich data about something that comes up all the time in our lives
  • The ability to find and tell the stories in that data

The reason I like the blog has nothing to do with naming babies. (I’m not allowed to name babies, anyway.)

I like it because we all encounter names every day, all the time, in every part of our life. We all have feelings and opinions about what names mean, but if you’re like me, they were mostly unconscious, unquestioned, and never subject to any statistical rigor. (Freakonomics has a well-known chapter about naming trends, which Wattenberg takes issue with).

Nevaeh (“Heaven” backward) is currently a more popular baby name than Sarah.  Brooklyn is more popular than either, and Sophia is more popular than all three combined. In 20 years, those names will conjure up images of college kids, and Brandon and Sarah will sound as much like Mom and Dad names as Gary and Debby do to my generation.

If you’re like most people, you probably had some opinions when you read the names in the last paragraph. But maybe the biggest thing I’ve learned from reading this blog is that the reactions and stereotypes that names provoke often reveal more interesting stories than the names themselves.

For example, you may have heard the urban legend about a mother who named her daughter Le-a, pronounced “Ledasha”. Wattenberg dissects this urban legend in an insightful essay (Part 1, Part 2, Part 3), which explains how apocryphal names like Le-a serve, across a wide variety of communities, as proxies for talking about race.

Here are a few of the other things I’ve learned from the blog:

That’s just a tiny sampling; if you think any of it sounds interesting, I recommend browsing through the blog’s extensive archives.

Asteroid 4942 Munroe

Whoa. There’s an asteroid named after me!

Amazing xkcd readers Lewis Hulbert and Jordan Zhu noticed that the International Astronomical Union—the organization in charge of official astronomical naming—was taking suggestions for what to name small Solar System objects. They submitted my name for asteroid (4942) 1987 DU6, and it was subsequently renamed 4942 Munroe.

I’m really touched. I spent all weekend telling everyone who wanted to listen (and probably some who didn’t) about the asteroid.

The first thing I did was try to figure out whether 4942 Munroe was big enough to pose a threat to Earth. I was excited to learn that, based on its albedo (brightness), it’s probably about 6-10 kilometers in diameter. That’s comparable in size to the one that killed the dinosaurs—definitely big enough to cause a mass extinction!

I texted Phil Plait to let him know that 4942 Munroe is four or five times the diameter of 165347 Philplait.

Unfortunately Fortunately, it’s in a fairly stable circular orbit between Mars and Jupiter, so it’s unlikely to hit the Earth any time soon.

4942 Munroe (!!!) is large enough that it would have noticeable gravity, although not much. If you were walking on the surface and you tripped and fell, it’d take you a minute to hit the ground. You could get into orbit around it by traveling at jogging speed, and might even escape its gravity entirely with a good jump.

Thank you so much. This is the coolest thing.

1190: Time

On Friday, xkcd #1190—Timecame to an end.

It was a huge project, but since it was all concealed within a single comic panel, I thought I’d end with this short post to explain what was going on. If you want to see the story yourself before I spoil anything, you can use one of the many excellent third-party Time explorers, like the Geekwagon viewer, or one of the others listed here.

When the comic first went up, it just showed two people sitting on a beach. Every half hour (and later every hour), a new version of the comic appeared, showing the figures in different positions. Eventually, the pair started building a sand castle.

There was a flurry of attention early on, as people caught on to the gimmick. Readers watched for a while, and then, when nothing seemed to be happening, many wandered away—perhaps confused, or perhaps satisfied that they’d found a nice easter-egg story about castles.

But Time kept going, and hints started appearing that there was more to the story than just sand castles. A few dedicated readers obsessively cataloged every detail, watching every frame for clues and every changing pixel for new information. The xkcd forum thread on Time grew terrifyingly fast, developing a subculture with its own vocabulary, songs, inside jokes, and even a religion or two.

And as Time unfolded, readers gradually figured out that it was a story, set far in the future, about one of the strangest phenomena in our world: The Mediterranean Sea sometimes evaporates, leaving dry land miles below the old sea level … and then fills back up in a single massive flood.

(A special thank you to Phil Plait for his advice on the far-future night sky sequence, and to Dan, Emad, and everyone else for your help on various details of the Time world.)

Time was a bigger project than I planned. All told, I drew 3,099 panels. I animated a starfield, pored over maps and research papers, talked with biologists and botanists, and created a plausible future language for readers to try to decode.

I wrote the whole story before I drew the first frame, and had almost a thousand panels already drawn before I posted the first one. But as the story progressed, the later panels took longer to draw than I expected, and Time began—ironically—eating more and more of my time. Frames that went up every hour were sometimes taking more than an hour to make, and I spent the final months doing practically nothing but drawing.

To the intrepid, clever, sometimes crazy readers who followed it the whole way through, watching every pixel change and catching every detail: Thank you. This was for you. It’s been quite a journey; I hope you enjoyed the ride as much as I did!

P.S. A lot of people have asked if I can sell some kind of Time print collection (or a series of 3,099 t-shirts, where you run to the bathroom and change into a new one every hour). I’m afraid I don’t have anything like that in the works right now. I just made this because I thought it would be neat, and now that it’s done, my only plan is to spend the next eleven thousand years catching up on sleep. If you liked the project, you’re always welcome to donate via PayPal (xkcd@xkcd.com) or buy something from the xkcd store. Thank you.

Dictionary of Numbers

I don’t like large numbers without context. Phrases like “they called for a $21 billion budget cut” or “the probe will travel 60 billion miles” or “a 150,000-ton ship ran aground” don’t mean very much to me on their own. Is that a large ship? Does 60 billion miles take you outside the Solar System? How much is $21 billion compared to the overall budget? (That last question is  why I made my money chart.)

A friend of mine, Glen Chiacchieri, has created a Chrome extension to help solve this problem: Dictionary of Numbers. It searches the text in your browser for quantities it understands and inserts contextual statements in brackets. It might turn the phrase “315 million people” into “315 million people [≈ the population of the United States]”.

As Glen explains, he once read an article about US wildfires which mentioned that the largest fire of the year had burned “300,000 acres.” This didn’t mean much to Glen:

I have no idea how much 300,000 acres is […] But we need to understand this number to answer the obvious question: how much of the United States was on fire? This is why I made Dictionary of Numbers.

Dictionary of Numbers helpfully informs me that 300,000 acres is about the area of LA or Hong Kong.

Wolfram|Alpha provides a lookup service like this, but you have to load the site and type in the quantity you’re curious about, which I never remember to do. (It’s also often short on good points of comparison.)

Dictionary of Numbers is a new project, so it’s got its share of glitches and rendering hiccups; it’s very much a work in progress. You can submit bug reports, feedback, and suggestions for data sources via a link on the project’s website.

I think these kinds of tools are a great idea, and I want to encourage them. Intelligence is all about context, and when computers get better at providing it, they make us smarter.

The extension can even be surprisingly funny, like when it seems to be making an oblique suggestion for how to solve a problem—e.g. “The telescope has been criticized for its budget of $200 million [≈ Mitt Romney net worth].” It can also come across as unexpectedly judgmental. Glen told me about complaint he got from a user: “I installed your extension and then forgot about it … until I logged into my bank account. Apparently my total balance is equal to the cost of a low-end bicycle. Thanks.”

You can get Dictionary of Numbers here.