Cosmologist on a Tire Swing

Cosmologist on a Tire Swing

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No matter how fast I swing, I can never travel outside this loop! Maybe space outside it doesn't exist! But I bet it does. This tire came from somewhere.

Special 10th anniversary edition of WHAT IF?—revised and annotated with brand-new illustrations and answers to important questions you never thought to ask—coming from November 2024. Preorder here!