Lorenz (one of the co-authors of this piece) has disproven his previous theory--that the rocks were temporarily embedded in a slab of ice which then floated. [1] I mean, I know that's how science is supposed to work, but in these days of politicized <i>everything</i> it's cool to see someone say "new data disproves my previous hypothesis" and continue working to find the real truth.<p>[1] <a href="http://www.livescience.com/37492-sailing-stones-death-valley-moving-rocks.html" rel="nofollow">http://www.livescience.com/37492-sailing-stones-death-valley...</a>
I've been to Racetrack Playa, and it's awesome. I'm glad a rational, scientifically plausible explanation has been found for the movement of the rocks.<p>You need to rent a Jeep with reinforced tires, otherwise you could find yourself in the same predicament as some people we met, who got a flat tire on their rented SUV at Racetrack Playa.
Ice sheets moving rocks, this has been seen before: <a href="http://skeptoid.com/episodes/4021" rel="nofollow">http://skeptoid.com/episodes/4021</a><p><i>"The surrounding mountains were still covered with snow, and the playa itself was firm but had a large lake covering about a fifth of its surface, perhaps an inch or two deep at its edges, concentrated at the playa's south end where it's lowest. We ventured out, armed with cameras, shortly before sunrise. The temperature was just above freezing. The wind, from the south, was quite stiff and very cold. When we reached the lake, we found to our great surprise that the entire lake was moving with the wind, at a speed we estimated at about one half of a mile per hour. The sun was on the lake by now and we could see a few very thin ice sheets that were now dissolving back into water. This whole procession was washing past many of the famous rocks. It's easy to imagine that if it were only few degrees colder when we were there — as it probably had been a couple of hours earlier — the whole surface would be great sheets of thin ice. Solid ice, moving with the surface of the lake and with the inertia of a whole surrounding ice sheet, would have no trouble pushing a rock along the slick muddy floor. Certainly a lot more horsepower than wind alone, as has been proposed. The wind was gusty and moved around some, and since the surface is not perfectly flat and with rocks and various obstructions, the water didn't flow straight; rather it swapped around as it moved generally forward. Ice sheets driven by the water would move in the same way, accounting for the turns and curves found in many of the rock trails."</i>
Still not quite sure how the trails themselves are formed if the rocks are riding on ice sheets 10's of meters in area, or am I reading this wrong / quickly?<p>Edit: n/m, it appears the ice sheets are massive and free-of-friction enough to actually <i>push</i> the rocks around. Cool!
Here's a human interest story on the study and its authors in a local paper: <a href="http://www.independent.com/news/2014/aug/27/death-valley-mystery-solved/" rel="nofollow">http://www.independent.com/news/2014/aug/27/death-valley-mys...</a>
"In addition, rock movement is slow and relatively brief—our GPS instrumented stones traveled at speeds of 2–5 m/minute for up to 16 minutes—so casual observation is likely to miss rocks in motion." Sounds like a passage that could be in Einstein's Dreams :)