Book · 2014
What If?: Serious Scientific Answers to Absurd Hypothetical Questions
by Randall Munroe
A cartoonist answers a stranger's question about dropping an entire thunderstorm as one giant raindrop, then keeps doing that for 300 pages.
What does Reddit think of What If?: Serious Scientific Answers to Absurd Hypothetical Questions?
r/AskScience doesn't review What If? so much as cite it, the way you'd cite a paper mid-argument. The ↑319 comment reaches for the giant-raindrop scenario, an entire thunderstorm's water condensed into one blob with a person inside it, and calls it the only example they had off the top of their head. The ↑219 comment does the same move for supernovas, the neutrino count from one AU away. The ↑56 comment remembers the nuclear-reactor-pool question but can't recall if it was from What If or its sequel How To, which says something about how thoroughly these blend together after enough years of citing them. The sharpest praise comes from someone positioned to judge: a working r/AskScience answer-writer (↑48) says Munroe does their own job better than they do. r/suggestmeabook barely registers, two unscored mentions since 2021. Nobody here is selling the book. They keep reaching for it because the question already has a good answer.
Community feedback & reader fit
Themes
- · Bizarre physics scenarios reused as ready-made citations in AskScience threads
- · The giant raindrop and the one-AU supernova neutrino count as recurring reference points
- · A working science-answer writer rating Munroe better at their own job
- · Confusion between What If and its sequel How To after years of citing both
Common praise
- + The ↑48 comment, from someone who answers science questions for a living, says Munroe does it better than they do.
- + The ↑268 comment tells strangers to just check it out from a library or buy it.
- + The ↑319 comment can summon the giant-raindrop scenario from memory alone, seven years after reading it.
Common criticism
- − Most of the top-upvoted comments cite What If as a source, not something anyone's actually reviewing.
- − The ↑56 comment mixes it up with How To, unsure which book the nuclear-reactor question came from.
- − r/suggestmeabook contributes only two unscored mentions since 2021, barely a signal next to r/AskScience's volume.
Who it's for
Keep this on the shelf if you're the person your group chat forwards weird physics questions to. The ↑48 comment is the best endorsement in the dataset precisely because it comes from someone who does this professionally and still rates Munroe higher. If you liked one XKCD What If column online, the book is just more of that, in depth, with citations, no paywall. Confusing it with How To is apparently common even among people who've read both, so don't worry about keeping the two straight before you start.
Mentions over time
Top subreddits
Which Reddit comments matter for What If?: Serious Scientific Answers to Absurd Hypothetical Questions?
The most relevant excerpts across the subreddits where this book is mentioned — opinionated, argued takes first, then top-upvoted mentions. Click through to read the full thread.
“This is the only reference I had off the top of my head, one of the XKCD What If columns. It asks "what would happen if you dropped all the water from a thunderstorm as one BIG drop?" As an additional exercise, it imagines a person inside the drop as it falls. > As the…
“Randall Munroe did a What If question about this a few years before covid 19. IIRC he concluded that the level of shut down needed to eliminate the common cold would probably not be feasible because we have to have a certain percentage of people keeping our various utilities and food supply chains o…
“There's a book called "What If?" by author Randall Munroe (author of xkcd.com comics) where people submitted crazy or silly scientific questions and he provided in depth, serious answers. You should check it out from a library or just go buy it if you like to wonder about these k…
“Same with Supernovas. Every time I try to figure out how massive the numbers are I'm reminded of the XKCD What If that points out that if you were 1 AU away from a star undergoing core collapse in a supernova, you'd die from the sheer number of neutrinos slamming into you (in addition to everything …
“A cavitating hypersonic whale would be a sight to see. Especially if it impacted anything at that speed... Does anyone know if Randal Munroe is doing another What If book soon?
“There's a book by XKCD creator, either "How to" or "what if" and it asks a question: what would happen if you swam in the water pool used to cool a nuclear reactor. It was very interesting, and iirc the basic answer was "nothing really, depending on how close to the reactor you were" Apparently wat…
“I've been answering science questions in this sort of format for a bit longer than Mr. Munroe has been running the What If? part of XKCD, but I think he's significantly better at it! The comparison is high praise indeed, thanks! Part of the reason, and I know Randall gives this justification too, i…
“The term 'near' means very little when talking about the speed of light, but others have pointed that out already. Given that you asked the question, I thought you might enjoy these two articles on XKCD What If! There's one where he tries to figure out what happens to a diamond meteor that hits the…
“This is the subject of an amazing XKCD ‘What If’ post. Here’s the link
“For most of the ocean, dilution is enough: unless you're near where the continued contamination is coming out, the amount of radioactive waste in the Pacific is near homeopathic (read: diluted to undetectable). Even then, water is an amazing radiation blocker: XKCD di…
“You could imagine a strange scenario where there are so many neutrinos passing through the eye that some of them induce beta decay, and the electrons that are released fly through the vitreous humor of the eye so fast that they produce Cerenkov radiation. In such a scenario, you'd see a blue glow. …
“>...yeah, sure, but if you're lost in the forest, you likely know which hemisphere you're in, whether you're upside down, and whether there's an eclipse at that moment. These are all excellent topics to contemplate. They might not answer your immediate question of "how to get out of this forest". …
“It's still relevant because if the mass of the earth was the same distance as the magnet, the magnet would no longer be able to lift the paper clip. The analogy requires both the difference in force and the difference in distance to work out. The first "What If?" book by Randall Munroe of XKCD fam…
“There's much good conversation here, so i'm just going to say this exact question crops up in *What If? 2* By Randall Munroe, which came out this week. If you're interested it might be worth checking out, both the original and the sequel are very good.
“Ooohhhh. Let me give you one. [What If *serious answers to absurd hypothetical questions*] It's an amazing book that I've read a bunch of times and recommended to many people. VERY fun. If y…
Convinced? Pick up What If?: Serious Scientific Answers to Absurd Hypothetical Questions
What else does r/AskScience read?
Other books mentioned in the same sub, ranked. Shared-sub overlap with this title breaks ties.
What If?: Serious Scientific Answers to Absurd Hypothetical Questions — frequently asked
Is What If? by Randall Munroe worth reading?+
Yes, on the evidence here. The ↑268 r/AskScience comment tells people to check it out from a library or just buy it, and multiple other top comments reach for its scenarios, the giant raindrop, the supernova neutrino count, years after reading them. Nobody in the displayed excerpts argues against it.
What does r/AskScience actually say about What If?+
Mostly, they cite it instead of reviewing it. The ↑319, ↑289, and ↑219 comments all use specific What If scenarios to answer someone else's question, treating the book as a settled reference rather than something up for debate. The closest thing to a review is the ↑48 comment calling Munroe better at this than a working science writer.
Is What If? the same book as How To by Randall Munroe?+
No, they're separate books, but the ↑56 r/AskScience comment shows how easily people mix them up: the commenter remembers a nuclear-reactor-pool question clearly but isn't sure which of the two it came from. Treat them as a matched pair rather than expecting either title alone to cover everything Munroe has answered.
Is Randall Munroe writing a sequel to What If?+
Unclear from what's here. The ↑63 r/AskScience comment asks outright whether Munroe is doing another What If book soon, and no reply in the displayed excerpts answers it. Treat that as an open question rather than a confirmed one either way.