A special 10th anniversary edition of the million-copy bestseller What If? from the creator of the wildly popular webcomic xkcd--revised and annotated with brand-new illustrations and answers to important questions you never thought to ask. 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? What if everyone only had one soulmate? What would happen if the moon went away? 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 his signature xkcd comics. (They often predict the complete annihilation of humankind, or at least a really big explosion.) In celebration of 10 years of unusual insight, Randall Munroe has revised his classic blockbuster to ask what if? x 10. The result is 10x the adventure of scientific inquiry. Featuring brand-new 2-color annotations and illustrations, this special anniversary edition is far more than a book for geeks, What If? explains the laws of science in operation in a way that every intelligent reader will enjoy and feel much smarter for having read.