The mystery of Death Valley’s moving rocks has baffled scientists ever since they were discovered. Now, thanks to time-lapse photography and custom GPS technology, we finally know what causes the “sailing stones” in California’s infamous desert.
The California national park has had an area known as Racetrack Playa, which to outsiders might sound like the latest song produced by Suge Knight. It’s actually a dry river bed that hasn’t seen water in quantities capable of consumption for a long time, a place where you would likely die of thirst if you did more than visit.
It’s this location where a peculiar phenomenon has taken place: Large rocks are seen with clear drag marks behind them, completely unaided by human effort as they move, even uphill.
What causes the rocks to move?
Scientists have theorized shifts in Earth’s gravitational pull, gale-force winds, slippery algae, aliens, and even late night pranksters as the reason behind the sailing stones. Gravity pulls downward, so the idea of the moving rocks being pulled uphill defies logic, especially with the algae theory. Gale-force winds wouldn’t leave such a clear trail of drag marks, most likely spraying sand beyond them if anything. The last two were most likely, if impractical.
The reason behind the Death Valley moving rocks was stranger than we’d thought as revealed in a series of photos taken with time-lapse photography via custom GPS devices.
— NBC News (@NBCNews) August 27, 2014
Frost forms on the surface of Racetrack Playa, creating a layer of extremely thin ice which apparently pushes the rocks across the wet and pliable mud as it breaks up. While the physics don’t seem likely, the evidence is almost as solid as the sailing stones themselves. You would expect ice that thin to simply crack around the edges of the rocks, but thanks to the water’s influence it has just enough force to start the rocks hydroplaning and baffle scientists.
The experiment was admittedly boring, claimed one of the scientists involved, since most of it involved simply waiting in a place most people don’t feel the need to linger.
NASA’s Ralph Lorenz expanded on the concept:
“It’s very quiet out there, and it’s very open – and you tend to have the playa to yourself. And the longer you stay out there, it just takes on this incredible sense of mystery.”
With the mystery of Death Valley’s moving rocks now solved, the amount of interest in the Racetrack Playa might dwindle. That’s the price of scientific curiosity though.
What had you thought was the truth behind the mystery of Death Valley’s “sailing stones”?
[image via Bing]