For many decades scientists have been stumped by the phenomenon known as sailing stones. Located in Death Valley, these 300-pound rocks appear to glide effortlessly through the sands. They are found in a particularly remote part of the Death Valley, which is why it has been so difficult to study them. Nicknamed the sailing stones because they are found on the dried lake known as the Racetrack Playa when they move they leave a cracked trail behind them in the mud.
The explanation for the movement of these boulders and rocks has seen everything from space aliens, to pranksters, to magnetic fields. However, no one has ever seen them actually move, which is why they have been able to remain so mysterious. Park ranger Alan Van Valkenburg has stated that you tend to have that whole section of the playa for yourself if you go out there, nobody is around at all. It is very quiet and very open, so a rock moving by itself really is quite incredible.
Scientists, of course, have tried to solve this mystery for many generations. They even thought dust devils were moving the rocks, or that the strong winds were moving these boulders that weigh up to 700 pounds. All the theories were eventually disproved, leaving us with zero explanation around the movement. Until now.
While researching the weather conditions on a hydrocarbon lake on Titan, NASA scientists became interested in comparing it with the Death Valley conditions. And Ralph Lorenz became intrigued by the sailing stones. He figured out what most likely was happening was that during periods of rain and temperature drops, the rock’s were being encased in ice. As the lake dried up the water levels were extremely low so the rock encased in ice was still scraping on the sandy floor but the conditions were good enough to let it float a little.
Lorenz figured out that if the winter conditions were just right in Death Valley, with enough water and ice, the rocks could float across the mud of the Racetrack Playa. And then in a light breeze, they would glide across the sands.