book hack

What If?

Randall Munroe

5 mins

3 key insights

Visual, audio & text

What If is a compilation of well-researched, science-based answers to some of the craziest hypothetical questions you can imagine.


What If?

What If?

by Randall Munroe


What do you think would happen if someone threw a baseball at 90% the speed of light? Do you know how fast you can hit a speed bump and still live? Or have you ever thought about how much force Yoda actually outputs in Star Wars?

If you've ever wondered what would happen if some of the craziest and most impossible events actually happened, you're not alone. What do you get if a former NASA roboticist opens up his website to field wacky questions and answer them with science? That's where Randall Munroe comes in. He is the author of the webcomic xkcd, which also hosts his "What If?" platform. Anyone can submit any question they can think of to his site, and Munroe uses real scientific principles to answer his favorites.

A few years ago, some of the best questions and answers were compiled into a book called What If?: Serious Scientific Answers to Absurd Hypothetical Questions. If you like science and you like humor, you're going to love this one.

Favorite quote

Remember: I am a cartoonist. If you follow my advice on safety around nuclear materials, you probably deserve whatever happens to you.

- Randall Munroe

Download the uptime app to

Read or listen, with different modes

Adjust audio speed in the app

Bookmark to save titles for later

Share your favourite Hacks


View the full Hack with Uptime