Scientist have been puzzled for decades as to how large rocks move across the dried-up lake bed in Death Valley. Theories on how these “sailing stones” move across the desert have ranged from slippery algae and high winds to alien tomfoolery.
In a study published this week in PLOS ONE, scientists observed the rocks actually moving for the first time ever and they now believe they know what is happening. In December 2013, a storm covered the lake bed in ice. A light but steady wind then kicked up and hundreds of rocks started to slide along the lakebed. The rocks traveled as much as 200 feet and as fast as 10 mph. For the first time, this was all captured on camera.