What If?: Serious Scientific Answers to Absurd Hypothetical Questions to make them shatter on contact?" The book was received positively by critics. Ethan Gilsdorf of the "Boston Globe" stated that "it’s fun to watch as Munroe tackles each question and examines every possible complication." According to Gilsdorf, "What If?" gives a view into "Munroe’s playful yet existentially-tinged worldview" by contrasting cataclysmic scenarios with more heady ideas, such as examining the effects of a magnitude minus-7 Richter scale earthquake. The "Huffington Post" remarked that "What makes Munroe's work so fantastic is a combination of two elements: his commitment to trying to answer even the weirdest question with solid science, and
Magnitude (astronomy) by astronomers are: The difference between these concepts can be seen by comparing two stars. Betelgeuse (apparent magnitude 0.5, absolute magnitude −5.8) appears slightly dimmer in the sky than Alpha Centauri (apparent magnitude 0.0, absolute magnitude 4.4) even though it emits thousands of times more light, because Betelgeuse is much farther away. Under the modern logarithmic magnitude scale, two objects, one of which is used as a reference or baseline, whose intensities (brightnesses) measured from Earth in units of power per unit area (such as watts per square metre, W m) are and , will have magnitudes and related by