What If? Serious Scientific Answers to Absurd Hypothetical Questions by Randall Munroe

Millions of people visit xkcd.com each week to read Randall Munroe's iconic webcomic. His stick-figure drawings about science, technology, language, and love have a large and passionate following. Fans of xkcd ask Munroe a lot of strange questions. What if you tried to hit a baseball pitched at 90 percent the speed of light? How fast can you hit a speed bump while driving and live? If there was a robot apocalypse, how long would humanity last? In pursuit of answers, Munroe runs computer simulations, pores over stacks of declassified military research memos, solves differential equations, and consults with nuclear reactor operators. His responses are masterpieces of clarity and hilarity, complemented by signature xkcd comics. They often predict the complete annihilation of humankind, or at least a really big explosion. The book features new and never-before-answered questions, along with updated and expanded versions of the most popular answers from the xkcd website.

Anyone who is familiar with Internet culture has either heard of xkcd, or either encountered one of the webtoon's inimitable comics. Randall Munroe's famous style has spawned a huge variety of comics on science, technology and philosophy, and has helped to make daily webcomics great again.
Right from its inception, xkcd and Munroe were asked to answer a variety of hypothetical scenarios by its readers - ranging from the curious (‘What would happen if a bullet as dense as a neutron star was fired into the Earth?') to the slightly macabre (‘What if the Earth was made entirely of protons and the moon entirely of electrons?'). Munroe started answering these absurd questions with a ton of Math and physics - that is, to say, seriously. The series of QnA was spun-off into a separate section of the site and was termed ‘What If' - this book is simply the entire section in print form, plus previously unseen questions.
Not everything in the book is about anarchy and destruction though - that is reserved for the second half of the book. The first half of the book is comprised of innocuous questions, mostly relating to lightning, time travel, and astronomy.
Even if you're not interested in computation and weird thought experiments, this book is a must-read, if only as a testimony to human imagination. Mind-blowing doesn't even begin to cover it. This is a work of art, and deserves to have space on every bookshelf.

This book is awesome. Randall Munroe does a really good job with explaining science to everyone (everyone who knows xkcd already knows this).

The topics are short but informative. You always get way more information than you thought, and with its on point humor it's just fun to read.

I really learned some new stuff, and even though most of the topics are really crazy, I already could shine with some knowledge or facts around my friends.

I really can recommend this to everyone. Fun!