How Explosives, a Robot, and a Sled Expose a Doomsday Glacier

Two Decembers ago, Erin Pettit layered up, slapped on goggles, cued up an audio book, and went on a hike--across Thwaites Glacier in Antarctica. Behind her, she dragged a sled loaded with a ground-penetrating radar, which fired pulses through a thousand feet of ice and analyzed the radio waves that bounced off the seawater below, thus building a detailed image of the glacier beneath her feet. Pettit--a glaciologist and climate scientist at Oregon State University--hiked alone through the snow, sometimes eschewing headphones for the absolute auditory stillness of the most remote landscape on Earth. "It was actually kind of an amazing, meditative field season," she says, "I just bundled up, I went out there and pulled my sled, and just walked for miles and miles." In case you were worried, her colleagues always knew where Pettit was; every so often someone would roll out on a snow machine to bring her supplies or to swap out the radar's battery.