These mysterious rocks have puzzled scientists for decades—until one geologist found the answer on his kitchen table
Start at the Furnace Creek visitor center in Death Valley National Park. Drive 50 miles north on pavement, then head west for another 30 miles on bone-rattling gravel roads. During the drive—which will take you four hours if you make good time—you’ll pass sand dunes, a meteor crater, narrow canyons, solitary Joshua trees and virtually no evidence of human existence whatsoever. But soon after cresting the Cottonwood Mountains, you’ll come upon a landscape so out of place even in this geologically bizarre park that it almost seems artificial.
Racetrack Playa is a dried-up lakebed, ringed by mountains, about 3 miles long and flat as a tabletop. During summer, the cracked floor looks prehistoric under the desert sun; during winter, it’s intermittently covered by sheets of ice and dustings of snow. But the dozens of stones scattered across the playa floor are the most puzzling part of the view. Ranging from the size of a computer mouse to a microwave, each one is followed by a track etched into the dirt, like the contrail behind an airplane. Some tracks are straight and just a few feet long, while others stretch the length of a football field and curve gracefully or jut off at sharp angles.
Staring at these "sailing stones," you’re torn between a pair of certainties that are simply not compatible: (1) these rocks appear to have moved, propelled by their own volition, across the flat playa floor, and yet (2) rocks don’t just move themselves.