Living Stones of Death Valley
An examination of the mysterious stones that move by themselves across the desert floor.
Filed under Aliens & UFOs, Ancient Mysteries, Paranormal
| Skeptoid #21 January 15, 2007 Podcast transcript | Listen | Subscribe |
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By Brian Dunning, Skeptoid Podcast
Episode
21 , January 15, 2007
http://skeptoid.com/episodes/
4021
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| The author with one of the rocks (Photo: Richard Saunders) |
If you're familiar with the American Southwest or even if you're a fan of the paranormal, you've heard of the mysterious stones that move across the surface of a dry lakebed in Death Valley called Racetrack Playa. Hundreds and hundreds of rocks, scattered about the surface of this several square mile mudflat, have left trails behind them where they've moved across the surface. Nobody has ever seen one move, despite many studies. I came as close as anyone could.
Proposed explanations run the gamut from natural to paranormal to alien. Strange magnetic forces, psychic energy, alien spacecraft, teenage pranksters, and even transdimensional vortices have all been proposed. The leading scientific hypothesis is that the rocks are moved by high winds, on rare occasions when the playa is wet enough to be extremely slippery, and conditions are just right. I've always had trouble with this explanation. I used to play in mud flats as a kid, and when a rock is glued onto that surface it's pretty damn hard to move. The rocks at Racetrack Playa are quite streamlined, and it's hard to imagine any wind strong enough to break their bond with the surface and shove them along deep enough to leave those trails. The real cause of the moving rocks, it turns out, carries a lot more punch than wind, and requires conditions that are not oddball and that are easily observable.
In the early spring of 2002, I made one of my many trips to Racetrack Playa with two friends, Dan Bocek and John Countryman. 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.
But don't take my word for any of this. I told you we had cameras, and I captured the event on video. It's well worth two minutes of your time:
That nobody has ever seen the rocks move is easy to believe. When there's water on the surface of the playa, you're not allowed to go out there — and indeed, you probably wouldn't want to. Thus there's nobody around when the ice sheets drag the rocks.
We missed the actual event, probably by a couple of weeks, so we didn't get the first real video of a moving rock. No doubt someone soon will. But we did see and document all the forces at play, and I think our explanation is far more plausible than any previous hypotheses.
© 2007 Skeptoid Media, Inc.
References & Further Reading
Bacon, D., Cahill. T., Tombrello, T.A. "Sailing Stones on Racetrack Playa." Journal of Geology. 1 Jan. 1996, Volume 104, Number 1: 121-125.
Cooke, Ronald U., Warren, Andrew, Goudie. Desert Geomorphology. London: UCL Press Limited, 1993. 211-212.
Dunning, Brian. "Moving Rocks of Death Valley's Racetrack Playa." YouTube. YouTube, LLC, 13 Mar. 2006. Web. 18 Nov. 2009. <http://www.youtube.com/watch?v=u1hoiHvOeGc>
Evans, Robert. "Dancing Rocks." Smithsonian. 1 Jul. 1999, Volume 30, Number 4: 88-94.
Reid, John B., Bucklin, Edward P. "Sliding rocks at the Racetrack, Death Valley: What makes them move?" Geology. 1 Sep. 1995, Volume 23, Number 9: 819-822.
Sharp, W. E. "The Movement of Playa Scrapers by the Wind." The Journal of Geology. 1 Sep. 1960, Volume 68, Number 5: 567-572.
Stanley, George M. "ORIGIN OF PLAYA STONE TRACKS, RACETRACK PLAYA, INYO COUNTY, CALIFORNIA." Geological Society of America Bulletin. 1 Nov. 1955, Volume 66, Number 11: 1329-1350.
Reference this article:
Dunning, Brian.
"Living Stones of Death Valley." Skeptoid Podcast. Skeptoid Media, Inc.,
15 Jan 2007. Web.
3 Feb 2012. <http://skeptoid.com/episodes/4021>
Discuss!
5 most recent comments | Show all 20 comments
Remember, you should always read with skepticism the comments of anyone too lame to put their real name & city.
I'm not sure a lot of these explanations are as solid as people think.
I've seen photos of rocks that have moved over flat, level surfaces, so a slippery gradient and gravity couldn't be the answer. And unless I'm mistaken (a possibility) this is a year-round phenomenon, so ice can't fully explain it either.
Todd G, Houston, TX
June 08, 2011 10:03am
I had a thought about this the other day. Perhaps there is a sporadic lack of gravitation pull or a horizontal gravitational pull due to some other phenomonon. Im wondering if a scientist had ever used an equipment to monitor for gravitation fluctiations? I heard recently that in canada there is a place that has less gravity because of an ice sheet that used to be there.
steve schulak, peoria az
July 08, 2011 1:30pm
thanks for the info.from the point icame to know about these rocks,i was really eager to know about them.and now i got my answer:)
hasanthi, andhrapradesh,india
August 05, 2011 6:09am
1/ The stones move due to the heating action of the sun on ice at dawn. The sun rises in the ENE in summer and ESE in winter. At dawn the frozen ground thaws on the sunny side of the stone with a very large and short lasting pressure drop due to the reduce volume of water as compared to the expanded volume of ice. The stone rapidly shifts directly towards the sun, pressure is equalised and all movement ceases until the next dawn.
2/ A summer dawn produces more frequent thawing than a winter dawn - hence the ENE prevalence over ESE.
3/ High surface area exposure to the sun means loaf shaped rocks alligned with the long axis perpendicular to the dawn move more than loaf shaped rocks aligned with the long axis towards the sun.
4/ The clay pan is nothing more than very small rocks. This sun causes the clay pan itself to move towards the dawn - hence the slight incline of the otherwise flat surface to the ENE.
Lesley Jean Roberts, Adelaide
December 03, 2011 6:25pm
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This is great. I have always been curious about this mystery. I never really could figure out, why oh why, do ghosts, aliens or the other weird creatures, would want to move rocks around in the middle of the desert! Finally an explanation that I can believe. Thanks!
banff, Vancouver, Canada
April 16, 2011 5:57pm