For over a century, the sight of heavy rocks sliding across Death Valley’s Racetrack Playa has baffled scientists and onlookers alike. In 2014, researchers finally captured evidence of these rocks in motion, revealing the secret behind this natural mystery.
Known as sailing stones, these intriguing formations rest on a dry lake bed in Death Valley National Park. They seem to glide across the parched landscape, leaving long trails. For years, people theorized about their movement—some speculated strong winds or even alien forces. But it took a unique combination of environmental conditions for science to unlock this enigma.
In December 2013, Richard D. Norris and his cousin James M. Norris began the Slithering Stones Research Initiative. They equipped stones with GPS trackers and set up time-lapse cameras to capture their movements. Initially, they expected to wait years without any action. However, their patience paid off sooner than anticipated. They recorded the stones moving at speeds of up to 15 feet per minute and, astonishingly, over 60 rocks shifted across the playa at once. One stone traveled 224 meters in just a few weeks.
According to Richard Norris, “Science sometimes has an element of luck. We were there at the right time to see it happen.” This underscores how unpredictable nature can be, reminding us of the interplay between patience and chance in scientific research.
So, what causes these rocks to slide? It turns out that delicate sheets of “windowpane” ice, only 3 to 6 millimeters thick, make them move. These fragile ice panels form overnight when temperatures drop and then break apart as the sunlight warms them. Floating ice not only creates a slick surface but also pushes the stones gently forward. The entire process is subtle yet fascinating, driven by light winds measured at around 9 to 11 mph.
Interestingly, not all rocks slide in the same manner. Their shape and texture play a pivotal role. Rocks with rough bottoms leave straight tracks, while smoother ones create curved paths. These trails can last for several years, gradually fading due to the harsh desert conditions.
The rocks themselves come in various sizes and compositions. Generally made of dolomite and syenite, they weigh anywhere from a few hundred grams to several hundred kilograms. The low-friction environment lets even the heaviest stones move with ease.
This captivating phenomenon draws many visitors to Death Valley, sparking conversations across social media platforms. People share images, videos, and theories, creating a lively online community. As we learn more about these sailing stones, they serve as a reminder of the wonders of nature and the curiosity that drives scientific discovery.
For those eager to dive deeper into the research, check out the PLOS One study, which outlines the detailed findings from this groundbreaking project.
