The ‘Sailing Rocks’ of Death Valley

I first read about these large stones in Death Valley that supposed moved on their own back in the late 1980s. Specifically, I remember comments by skeptics, who found the idea hilarious. They suggested that the people who were reporting that the stones rolled across the valley on their own were scientifically challenged. In other words, wackos. If the stones did move, it was the work of pranksters. End of story. I wish I still had that debunking article.

Yes, the skeptics said the stones had trails behind them that seemed to indicate movement, but the logical answer was that someone pushed them across the valley floor—known as Racetrack Playa— or created the lines behind them.

They assured us that stones‑especially large ones weighing hundreds of pounds, don’t move on their own. They used this example as a way of showing the gullibility of people who believed in the paranormal, and accepted things that weren’t scientifically sound.

Well, now we know for a fact that the stones do move across Racetrack Playa, and pranksters are not the cause. We also know the mechanism by which they move.

It’s an interesting example of the process that takes place when the veracity of an idea shifts from the realm of the impossible and implausible to acceptance.

First there is ridicule. Then when evidence is presented, which might include measurements, strong doubts are raised and the evidence is dismissed because the idea is still preposterous, outside of scientific reality.

Finally, more evidence is presented and the explanation for what seems impossible is linked to a scientific truism. In the case of the so-called ‘sailing rocks,’ forces of erosion—water and ice—move the rocks along. The theory was supported by GPS readings and video proof. The skeptics accept the explanation, and they tell us that they knew it all along, that it’s another victory for science over nonsense. No alien intervention or mysterious magnetic forces were involved.

The problem is that the debunkers would not have solved the mystery. Because there was no mystery. Rocks don’t move on their own. Period. End of story.

Fortunately, there are still scientists who are curious about the unknown, and not simply in the business of defending the current scientific paradigm. Some tried to show that dust devils or strong straight-line winds moved the stones. But no one had seen the rocks moving.

In some cases the rocks’ trails were measured to be as long as 820 feet (250 meters), according to Slate.com. Some of the trails formed a graceful curve, while other trails created a straight line, then an abrupt shift to the left or right, which further baffled researchers.

In 2006, Ralph Lorenz, a NASA scientist investigating weather conditions on other planets (hello aliens!), took an interest in Death Valley. In particular, Lorenz wanted to compare the meteorological conditions of Death Valley to those near Ontario Lacus, a vast hydrocarbon lake on Titan, a moon of Saturn.

That pursuit led him to take an interest in the enigmatic sailing stones of Racetrack Playa.

Lorenz developed a kitchen-table model — using an ordinary Tupperware container — to show how the rocks might glide across the surface of the lake bed.

“I took a small rock and put it in a piece of Tupperware, and filled it with water so there was an inch of water with a bit of the rock sticking out,” Lorenz told Smithsonian.com.

After putting the container in the freezer, Lorenz ended up with a small slab of ice with a rock embedded in it. By placing the ice-bound rock in a large tray of water with sand at the bottom, all he had to do was gently blow on the rock to get it to move across the water.

And as the ice-embedded rock moved, it scraped a trail in the sand at the tray’s bottom. Lorenz devised his clever experiment by researching how the buoyancy of ice can cause large rocks, when encased in ice, to move by floating along tidal beaches in the Arctic Sea.

The ultimate proof came when James Norris, a research engineer, attached GPS to stones and set up video cameras. The right conditions eventually occurred and he had documented Lorenz’s theory.