Cartoonist (and former NASA roboticist) Randall Munroe illustrates the questions that keep you (or at least him) up at night. Whether that’s “What would happen if you tried to hit a baseball pitched at 90% the speed of light?” or “How much of the Earth’s currently-existing water has ever been turned into a soft drink at some point in its history?” he’s got you covered.
On the TED2014 stage, the mind behind the webcomic xkcd — which might be the only comic with a haiku made of code, the sub-title “drawn during an endless NASA lecture,” the directive “What Would Escher Do?”, or (finally!) the extra-credit question for the Turing test — explains the one question from a reader that really stumped him.
“If all digital data were stored on punch cards, how big would Google’s data warehouse be?” reader James Zetlen asked Munroe in an email message. A question Munroe couldn’t just Google, he set off on an information scavenger hunt. “I started with money,” he says, “Google has to reveal how much they spend” — and with this information, he could narrow down the answer by putting caps on things like the number of data centers Google could afford to build, and how much of the world’s hard drive market they take up.
Next, he moved to electricity. Google has released numbers on its average power use, he found, so with that, paired with information on Google’s spending, things got easier. “When you know how much they spent, and also know how much power it takes, you can use the ratio of those numbers to figure out for data centers where you don’t have that information,” he says.
He likes the mystery of working with limited information, of building a model to solve for what you don’t know with what you do. “It’s nothing more than solving a Sudoku puzzle,” he says. But it’s exciting. And satisfying. “I love calculating these kinds of things,” he says, “not because I love math for its own sake; I love that it lets you take some things you know, and by moving some symbols around, you find out something you didn’t know that’s surprising.”
Did he ever answer Zetlen’s question? Well, sort of. On xkcd, he writes: “Let’s assume Google has a storage capacity of 15 exabytes, or 15,000,000,000,000,000,000 bytes. A punch card can hold about 80 characters, and a box of cards holds 2000 cards … 15 exabytes of punch cards would be enough to cover my home region, New England, to a depth of about 4.5 kilometers. That’s three times deeper than the ice sheets that covered the region during the last advance of the glaciers.”
The mystery didn’t end there, though. He never expected to get an answer from Google, but one day, he did. They contacted him saying, “Someone here has an envelope for you.”
“It was punch cards,” he says. The cards contained codes that revealed codes that revealed equations that revealed more equations, which finally led to … “No comment.”
“I have a lot of stupid questions,” Munroe says, “and I love that math gives me the power to answer them sometimes.” So next time you have a question that you don’t know how to calculate, send it to him. We think he’ll find a way.
Munroe’s first book, What If?: Serious Scientific Answers to Absurd Hypothetical Questions, will be released in September.