The Indonesian earthquake and tsunami happened when 31-year-old Karen Thompson Walker was pursuing her M.F.A. at Columbia. She was struck by the revelation that the force had been powerful enough to shorten the length of the day by microseconds.

“I thought it was so haunting that something we think of as unchanging— sunrise and sunset, the length of a day—could be changed,” says Walker.

She wrote a brief story and set it aside for a few years, but then picked it back up while working as an editor at Simon & Schuster, sensing it could be a novel. The Age of Miracles (Random House) has a more extreme premise than its inspiration—11-year-old Julia and her family wake up one morning to news that the Earth’s rotation is slowing, causing each day to grow first to 25 hours, and then 26. Set against this apocalyptic circumstance is Julia’s coming-of-age story. The book has already sold in 25 foreign territories, and River Road Entertainment, the production company behind Brokeback Mountain and The Tree of Life, has optioned movie rights.

Random House executive v-p and associate publisher Kate Medina snapped up the title from Eric Simonoff of William Morris Endeavor. “When I first read this book, I couldn’t sit down. I felt as if it had really happened to me,” says Medina. “It shows the fragility of everything, and yet it’s affirmative because the people keep going.”