Q: What would happen if a beloved web comic created a series of ... physics explainers?
Randall Munroe began his career in physics working with robots at NASA's Langley Research Center. He is famous, however, for engineering a creation of different kind: the iconic web comic that is xkcd. Last week, Munroe won the web's wonder for approximately the thousandth time when he published comic #1110, "Click and Drag," a soaring, spanning, surprising work that encouraged users to explore a fanciful world through their computer screens.
But Munroe, work-wise, is no longer dedicated exclusively to xkcd. He recently launched "What If?," a collection of infographic essays that answers questions about physics. Published each Tuesday, the feature -- a blog extension of the xkcd site -- aims to analyze the kind of wonderful and fanciful hypotheticals that might arise when the nerdily inclined get together in bars: "What would happen if the Moon went away?" "How much wood would a woodchuck chuck ...?" Some of What If's recently explored questions include: "What if everyone actually had only one soul mate, a random person somewhere in the world?" and "If you went outside and lay down on your back with your mouth open, how long would you have to wait until a bird pooped in it?" and -- the most recent entry -- "If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color?"
I recently spoke with Munroe about What If, xkcd, creativity, baseballs pitched at 90 percent of the speed of light ... and how, for him, The Lord of the Rings helped lead to it all. The conversation below is lightly edited and condensed.
First things first: Why did you create What If?
It actually started with a class. MIT has a weekend program where volunteers can teach classes to groups of high school students on any subject you want. I had a friend who was doing it, and it sounded really cool -- so I signed up to teach a class about energy, which I always thought was interesting, but which is a slippery idea to define. I was really getting into the nuts and bolts of what energy is, and it was a lot of fun -- but when I started to get into the normal lecture part of the class, it felt kind of dry, and I could tell the kids weren't super into it. And then we got to a part where I brought up an example -- I think it was Yoda in Star Wars. And they got really excited about that. And then they started throwing out more questions about different movies -- like, "When the Eye of Sauron exploded at the end of The Lord of the Rings, and knocked people over from this far away, can we tell how big a blast that was?" They got really excited about that -- and I had a lot more fun doing it than I did just teaching the regular material.
So I spent the second half of the class just solving problems like that in front of them. And then I was like, "That was really fun. I want to keep doing it."
So What If was basically a spin-off of the class?
That was where the idea came from. I actually wrote the first couple entries quite some time ago, based on questions students asked me in that class -- and then on another couple questions that my friends had asked. It was only recently that I finally managed to get around to starting it up as a blog.
The variety of the topics you tackle is incredibly broad. How do you figure out the best way to explain all these different, complicated subjects to people?
Part of what I'm doing is selectively looking for questions that I already know something interesting about. Or I've stumbled across a paper recently that was really cool, and now I'll keep an eye out for a question that will let me bring it up -- something I can use as a springboard. So in a conversation, someone might say, "Money doesn't grow on trees." Okay, well, what if money did grow on trees? Our economy would collapse. On the other hand, we would switch to a new currency. It's complicated.
What I like doing is finding the places in those questions where normal people -- or, people who have less spare time than I do -- think, "This is stupid," and stop. I think the really cool and compelling thing about math and physics is that it opens up entry to all these hypotheticals -- or at least, it gives you the language to talk about them. But at the same time, if a scenario is completely disconnected from reality, it's not all that interesting. So I like the questions that come back around to something in real life.
And the great thing with this is that once someone asks me something good, I can't not figure out the answer, you know? I get really serious, and I'll drop whatever I'm doing and work on that. One of the questions I recently answered was, "What if, when it rains, the rain came down in one drop?" And I was like, "Well, how big would that drop be?" I know a little bit about meteorology, and then, before I knew it, I had spent four hours working out the answer.
Why that need to answer? Is it because people are asking you -- because you want to help them out by answering the questions for them?
Oh, no, no, no, there's nothing altruistic about it! It's just like, once it gets in my brain, it keeps bugging me, and I don't know the answer, but I'm really curious. What really happens is: I have an idea for what the answer is, but then I want to figure out if I'm right or not. So I have to keep working to find out. And oftentimes, in the process of learning I'm wrong, I'll run into something even cooler. And then once I find that, I just want to tell everyone about it.
So I basically set up this blog to flatter all of my random impulses. And it's been a lot of fun so far.
And how do you decide which questions you ultimately commit to answering?
For the first few entires I wrote, I just wanted to make sure this format made sense. So I wrote a couple entries with questions just from my friends. And then when we put up the blog, we included an "Ask a Question" link. And since then, the volume of questions has been high enough that I don't think any set of two or three people could read them all. So I pretty much just sit down whenever I have a few spare hours and go through them and answer the questions that come in and try to see if there's anything that would make a good article.
Of the ones you've done, do you have a favorite so far?