What If? by Randall Munroe Summary

What If? Serious Scientific Answers to Absurd Hypothetical Questions is a 2014 book where Randall Munroe, creator of xkcd, uses physics, math, and humor to tackle bizarre scenarios like "What if a baseball were pitched at 90% the speed of light?" or "Could you survive jumping into a nuclear fuel pool?" Each chapter blends rigorous scientific analysis with witty illustrations and pop-culture references.

This book is ideal for science enthusiasts, xkcd fans, and anyone curious about unconventional scientific exploration. Munroe’s accessible yet precise explanations cater to both casual readers and technical audiences, making complex concepts like relativity and thermodynamics engaging through absurd hypotheticals.

Yes—What If? offers a unique mix of entertainment and education, perfect for readers who enjoy thought experiments backed by real science. Its humor, stick-figure comics, and surprising conclusions (like a baseball causing a nuclear explosion) make it a standout in popular science literature.

Munroe calculates that a baseball pitched at 90% light speed would trigger a thermonuclear explosion, obliterating the stadium and surrounding city. The ball’s energy would ionize air molecules, create a plasma shockwave, and leave a crater—all before the batter even swings.

If Earth’s rotation halted abruptly, the atmosphere would continue moving at 1,000 mph, generating catastrophic winds that flatten structures and trigger global fires. Survivors would only exist near the poles or in underground shelters due to reduced wind speeds there.

Building a periodic table with bricks of each element would cause instant disaster: sodium reacts explosively with air, fluorine gas is lethal, and radioactive elements like uranium would create a nuclear blast. Munroe concludes this "table" would level cities within seconds.

Munroe combines precise physics and math with humor, using "back-of-the-envelope" calculations to simplify complex topics. He clarifies assumptions (e.g., ignoring air resistance) and often pivots to unexpected conclusions, like using lasers to heat the Moon—which would also ignite Earth’s atmosphere.

Some readers note that certain answers oversimplify science or rely heavily on hypotheticals, which may frustrate those seeking practical insights. The repetitive structure of posing and dismantling absurd scenarios can feel formulaic, though fans argue this is part of its charm.

Unlike traditional science books, What If? prioritizes humor and creativity over real-world applications. It’s closer to Mary Roach’s What If? than Stephen Hawking’s works, with a focus on absurdity-driven learning rather than systematic theory.

The book’s emphasis on critical thinking and playful curiosity aligns with growing interest in STEM education. Its viral questions, like surviving a mole (animal) planet or charging a phone via lightning, remain popular in online science communities.

Yes, Munroe punctuates chapters with signature xkcd-style stick-figure comics. These visuals humorously underscore key points, such as a character panicking during a "hair dryer apocalypse" or a dinosaur debating orbital physics.

Released in 2022, What If? 2 continues Munroe’s tradition of answering absurd questions, like "Could you power a city with tornadoes?" or "How many cats would it take to replace the Moon?" It maintains the original’s blend of rigorous science and humor, expanding on fan-favorite themes.