'What If' : An Entire Book Devoted To Absurd Hypotheticals

LYNN NEARY, HOST:

Randall Munroe spends a lot of time answering absurd questions like what if everyone actually had just one soul mate? Could ever meet? He gets such questions from fans of his popular web comic at xkcd.com. A physicist who used to work on robotics for NASA, Monroe takes these questions very seriously - well, sort of seriously. He uses his expertise to come up with the best answers science can offer, then illustrates his answers with whimsical cartoons. The result is both fascinating and ridiculous. Take that soul mate question. In brief, here's what Munroe came up with.

RANDALL MUNROE: So I imagined a system of, like, everyone would get on these treadmills. And they'd be swept past each other. You know, you get the whole population of the Earth going past each other, making eye contact as they go with as many people as they can. Just taking a moment to like yes, yes, no, you know, no, no, no.

NEARY: Of course, this would take some time.

MUNROE: If everyone spent eight hours a day, 365 days a year on this, you could, in theory, pair of everyone with their soul mates within a few decades.

NEARY: Munroe has now collected his serious scientific answers to absurd hypothetical questions in a new book called "What If?" He says some of his best questions come from little kids.

MUNROE: 'Cause I find that the questions from adults are more like they're trying to be as wacky as possible. But the kids ask very simple questions that sometimes have kind of surprising consequences. Like one guy wrote in - he said, my daughter wants to build a billion-story building. I haven't been able to convince her, like, that this is not possible. And so maybe you can take a crack at it. And so I wrote an article, you know, explaining to her, you know, if you try to build a building progressively higher, here are the problems you're going to run into. Eventually, it gets so talk, you know, that it collapses. But then you figure out a way to build it stronger. But then it gets so tall that it's sticking out into orbit and satellites start colliding with it, you know. And then it takes you through all these different interesting physics ideas.

NEARY: Does it take any of the fun out of somebody's sort of fantasy about a billion-story building when you do answer it scientifically? Does it take the fantasy away?

MUNROE: I don't know. I think, you know, maybe a billion-story building, there are some logistical problems you run into. But the same time, you get to paint this picture of these orbiting stations and this tension on the building that, you know, you'd have these cables and these incredibly high-speed elevators that are, like, beamed up by lasers sending power back and forth because you have to solve that problem of how do you power the elevators. And, you know, it end up painting a wilder picture than what you were originally starting with. And I think that, you know, can be even more exciting and more romantic.

NEARY: Sometimes you wind up with answers that seem very far removed from the premise. I'm thinking of the question about what would happen if everyone in the world gathered in one place and jumped the same time. And the answer to that question lead to another problem that had to be solved involving getting home from Rhode Island. (Laughter).

MUNROE: A couple of different people have tackled this, you know, said, oh, if everyone jumped at once in one place, would it disrupt the Earth's orbit or something. And the answer to that is a little bit disappointing, which is that not a lot would happen. I thought, well, there's not a lot I can say about that. But then I said wondering, like, wait a minute. You've gathered everyone in the world in one place, magically. That's the premise of the question. But then what happens?

And I started trying to figure out, if you gathered everyone, you know, in Rhode Island - they would take up an area about the size of Rhode Island - then, you know, how many people can get out of Rhode Island per hour. What's the capacity of all the ports and, you know, the airports, the ships. How many cars are there in Rhode Island? And then, it turns out the rate is not that high. So it brings you to another question, which is how much food is there in Rhode Island because there's no one working the farms to supply more food to Rhode Island because everyone is already in Rhode Island. It turns out, within a matter of a couple of weeks, Rhode Island would be the graveyard of most of the human race in this scenario.

NEARY: You also have a series of questions that you don't answer. You sort of called them weird and worrying questions I think because you find these just a little too strange to deal with. Now the one that I wanted to mention 'cause I think it's pretty strange too is this - how fast would a human have to run in order to be cut in half at the bellybutton by a cheese cutting wire?

MUNROE: Yeah. That's in a category of question that I haven't answered because I don't want to think about that. It's just, like, my skin crawls imagining that. Another question like that was - how cold would your teeth have to get in order for a cup of hot coffee to make them shatter on contact? And that's a question I've never gotten past just the initial mental image.

NEARY: Do you have your own what-if questions?

MUNROE: Yeah. You know, I'm looking at a studio, and I might think - if I'm daydreaming in between taping - you know, what if I filled the studio with water. Would the windows be strong enough to hold up? How many playpen balls would it take to fill it if you wanted to make a ball pit here? How much would that cost, you know?

NEARY: How did you get into this in the first place? You were a physics major in college. Is that right?

MUNROE: Yeah. And a friend actually mentioned that there was an MIT program where you could teach classes to high schoolers. So I did one on energy. And I found that the students got way more interested when I started bringing in interesting, real-world examples 'cause a lot of the time, you just do, like, the physics of a ball rolling down an inclined plane. And it's nice 'cause it simplifies everything, but the same time, it makes you not really care what the answer is. And so I found that when I picked questions that were interesting - which is the whole reason we want to develop these physics tools in the first place - that people found it was a lot more fun to follow along.

NEARY: Randall Munroe is the creator of "xkcd" the web comic and also author of "What If?: Serious Scientific Answers To Absurd Hypothetical Questions." He joined us from our studios in New York. Thanks for being with us.

MUNROE: Thank you.

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