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If a hydra breaks in two, each half of the ageless sea creature grows into a fully formed organism. Planarian worms, axolotls, sea stars, and certain geckos regrow lost body parts as well, but this select club excludes humans and other mammals. People can regenerate small pieces of tissue, but lost limbs are gone forever.

When Caltech’s Nadia Lapusta creates computer models of earthquakes, she must integrate an astonishing range of data—on scales from thousands of kilometers down to microns and from millennia down to thousandths of a second. That’s because to understand the big and slow, she needs to understand the tiny and fast. “Large-scale earthquake ruptures—even those around 8 on the Richter scale—are ultimately happening in very narrow layers of granulated rock,” she says. In fact, where one side of a fault moves against the other, those layers are powdered so thin that a stack of a thousand grains would equal the thickness of a credit card. And although a fault can go eons between destructive quakes, the first slip that kicks off the shaking can take place in a blink.