Randall Munroe is an engineer, author and cartoonist who is best known for creating the webcomic xkcd. With the tagline “a webcomic of romance, sarcasm, math, and language”, covers just about everything, from science and philosophy to pop culture. Munroe has also written several books, including and its recently released sequel, , which playfully tackle the strange scientific questions posed by his readers.
Munroe speaks to New Scientist on what draws him to physics, his writing process – and some of his favourite snippets from the new book.
Before your successful cartooning career, you studied physics. What drew you to the subject?
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If you are really interested in the theoretical mathematical structures behind things, you sort of peel off into the world of pure math. If you’re interested in the practical applications, it’s hard to not get sucked into engineering.
It is the people who are right in the middle, where they are really interested in simplifying, but they keep wanting to anchor it back to practical things, who do physics. I feel like I am on that seesaw back and forth, I have a hard time caring that much about math when I can’t apply it to something.
I have a physics degree myself, so I can relate!
You know, there are a surprising number of cartoonists who have physics degrees. There’s my web cartoonist friend Zach Weinersmith, who does. I read growing up in the newspapers, which is by Bill Amend, who also has a physics degree.
In fact, of all the people who got physics degrees and then did a career change into cartooning who were born on 17 October, I am only the second most successful. Number one is Mike Judge, who did Beavis and Butt-Head.
Why do you think so many physicists turn their hand to cartooning?
The joke about physicists is that they will assume a spherical cow in a vacuum. They assume everything is really idealised until they can get to a few principles that govern it and, in a way, that is sort of like cartooning. You take a person’s complicated face and you simplify it down to one that just shows the bits that you want to show.
I think all of science is probably like that to some extent.
So, your new book tackles some pretty absurd questions. How do you pick them? And how do you go about finding the answers?
For me, my favourite questions are the ones where I don’t know the answer when I see it, but I have an idea of what the answer might be and I want to go find out if I am right or not.
Usually, I don’t just Google the subject, I think of an avenue that might solve it. I think, maybe this equation could apply there. I will go look up papers of people applying those methods to that kind of problem and see if I can find one where it is similar enough that I can apply those same formulas.
How do you know whether you are right?
One thing I learned early on with drawing comics, especially because many good scientists read them, is to be humble about assuming that I am right about things. If I make a joke about some law or some area of science, the person who came up with that law or published that paper might very well read it.
Sometimes, when I’ve written up an answer, I’ll send it to someone who’s an expert in that area and say: “Hey, does this look great to you? Is there anything I’m missing?”
I do also have a fact-checker who is a physicist. He went through and redid my calculations because what I am prone to is mixing up positives and negatives.
That’s very handy.
I didn’t do that at first. But, you know, with publishing things on the internet you quickly learn to.
Is there any such thing as a question that is too absurd for you to answer?
Now and then there’s a question where the answer is a bit too gruesome for me. It’s fun when you’re doing physics to study extreme circumstances. But when you have to spend too much time reading medical forensic textbooks, I don’t really want to do that.
One of the popular questions is: what would happen if you’ve released a bunch of dinosaurs into the modern savannah, or Canada or something? Would they become the top predator or not?
Of course, Jurassic World Dominion talked about it. This is a question that’s tricky because the real answer doesn’t come from biology. The real answer is that the same thing would govern them that governs other predators, which is whether humans shoot them or not. Then the question gets into complicated international politics.
What is the weirdest question you answered in your book?
There was a group of students who asked about what would happen if you pumped pure ammonia into your stomach. First of all, I was like, somebody should check on these children.
But that’s how I learned that there’s, like, surprisingly little acid in your stomach. I imagined it being sort of a big bag filled with acid, but it’s more like a bag wetted with acid. So, after immediately neutralising all the stomach acid, you then have pure ammonia coming in which would set to work on disintegrating the walls of your stomach. This is where I learned the word saponification – a conversion to a soap.
In our last interview with you, we asked you to tell us one thing that would blow our minds. Let’s finish on that again.
Someone asked me in the book: what percentage of all humans who have ever lived are my ancestors?
It varies a little bit based on where in the world you’re from and who your family is. But for most people, the answer is about 10 or 15 per cent.
So, if you find the bones of some human from a cave somewhere from 10,000 or 15,000 years ago, there’s a 1-in-8 chance that person is your ancestor.
Wow! That’s incredible.
Another question I answered in the book was: if every country’s borders extended up to space forever, what country owns most of the galaxy at any given time?
The answer is Australia – most of the galactic core is in Australian airspace.
Lucky Australia!
