As a member of Amazon Prime, Amazon helpfully told me I was entitled to a free Kindle Ebook, and I chose this one to read; I love the XKCD web comic at https://xkcd.com/ (updated comic on Mondays, Wednesdays, and Fridays), which I’ve been checking out for a few years now, and this book and illustrations are by the same guy.
As a CNU graduate with a degree in physics, followed by a few high-power jobs for guys with degrees in physics, the author gets a lot of submissions of questions to his What If? page at https://what-if.xkcd.com/154/ , and this book is made up of some of those questions (and answers). Among the questions are “If every person on Earth aimed a laser pointer at the Moon at the same time, would it change color?” (short answer: no), “What would happen if you made a periodic table out of cube-shaped bricks, where each brick was made of the corresponding element?” (short answer: death and destruction), “Is it possible to build a jetpack using downward-firing machine guns?” (short answer: yes, but don’t try this at home), “How long could a nuclear submarine last in orbit?” (short answer: until the air in the sub ran out), and “If an asteroid was very small but supermassive, could you really live on it like the Little Prince?” (short answer: if you ran too fast, you’d enter orbit around your asteroid). There is a lot of science stuff and physics stuff and chemistry stuff brought into play to answer these and other burning questions, but not so much that you feel at all like you are reading a textbook.
I very much enjoyed reading this book, and I recommend it to anyone needing a break from deeply serious thoughts.