Slip Sliding Away

December 2, 2007 1:46 AM

The Mystery of the Sliding Rocks of Racetrack Playa. One of the most interesting mysteries of Death Valley National Park is the sliding rocks at Racetrack Playa (a playa is a dry lake bed). These rocks can be found on the floor of the playa with long trails behind them. Somehow these rocks slide across the playa, cutting a furrow in the sediment as they move. Some of these rocks weigh several hundred pounds. That makes the question: "How do they move?" a very challenging one. [Via]. For more in-depth information, including maps and additional pictures, see Paula Messina's website about the Sliding Rocks.
posted by amyms (37 comments total)

Mystery solved, it's the Canadians
posted by mattoxic at 1:57 AM on December 2, 2007 [1 favorite]

hehe mattoxic!
posted by amyms at 1:59 AM on December 2, 2007

Previously.
posted by Slithy_Tove at 2:47 AM on December 2, 2007

I feel like I've seen this 'mystery' crop up a number of times, only to recall having read explanations or even seen videos of the phenomenon explained. We should have known all along it was the Canadians.
posted by derami at 2:55 AM on December 2, 2007

I've never been impressed by this mystery, because I always think to myself: "Get a damned time-lapse -- or motion-activated -- camera, set it up out there, and wait." Boom! Easily solved. In fact, wasn't there news just a few months ago that said it was due to a combination of overnight freezing water and winds?

Or Canadians. Always Canadians.
posted by barnacles at 3:08 AM on December 2, 2007

Well what the fuck do you want us to do? You're trying to take away our beer fridges!
posted by blacklite at 3:16 AM on December 2, 2007 [6 favorites]

"Get a damned time-lapse -- or motion-activated -- camera, set it up out there, and wait."

There have been many long term studies on the rocks, over years, and ice has not been definitively determined to play a factor in all the movements, although ice sheets do form and do play a part in at least some.

Time lapse cameras are relatively useless as these rocks don't move every night, sometimes they take years, and it is not every rock. Two similar rocks from the same dolomite source, and one of them will move, the other will not.

Rocks also disappear and then are found later a considerable distance away.
posted by Henry C. Mabuse at 3:35 AM on December 2, 2007 [1 favorite]

from Slithy_Tove's previously link:

"A likely explanation of the movement of the stones.
posted by hortense at 9:56 AM on December 31"

According to the video, it's the result of a large shallow rain pool on the edge of the playa. When a heavy wind blows, it pushes the water over the dry lake bed in thin sheet very quickly. Then as the temperature drops and ice flows form that push the stones. The ice then melts and the water evaporates leaving no trace but the muddy tracks behind the stones.

cool stuff.
posted by Merik at 3:43 AM on December 2, 2007

Time-lapse cameras may not be that helpful, but the USGS hooked up GPS devices to record the position of the rocks. They concluded that the wind is doing it.
posted by grouse at 3:43 AM on December 2, 2007 [2 favorites]

naw, mattoxic, it's the Scots. We invented it, then the Canadians started cheating, but changed the rules so it became okay.
posted by scruss at 4:18 AM on December 2, 2007

Rocks also disappear and then are found later a considerable distance away.

A cynical person might reckon that this is done by folks who are aware of The Mystery and want to fuck with researchers.

Great USGS links, grouse!
posted by barnacles at 4:54 AM on December 2, 2007

"A cynical person might reckon that this is done by folks who are aware of The Mystery and want to fuck with researchers."

That's what the researchers thought.
posted by Henry C. Mabuse at 5:33 AM on December 2, 2007

So, Henry, are you saying that the researchers are cynical?
posted by micayetoca at 5:42 AM on December 2, 2007

You say that like it's a bad thing.
posted by Kirth Gerson at 6:28 AM on December 2, 2007

I've never been impressed by this mystery

Don't be a playa hater, Barnacles.
posted by Horace Rumpole at 6:30 AM on December 2, 2007 [10 favorites]

(the USGS study is of course the one made by Paula Messina; see the original post for a link to her site)
posted by effbot at 6:45 AM on December 2, 2007

Did she fund her study of them by selling naming rights to each rock?
posted by nax at 7:51 AM on December 2, 2007

These rocks...they move?
posted by waldo at 8:35 AM on December 2, 2007

Good one, Horace Rumpole.
posted by wsg at 8:38 AM on December 2, 2007

There is no rock.
posted by The Deej at 8:40 AM on December 2, 2007

Did she fund her study of them by selling naming rights to each rock?

Dibs on Mr. Slidy Pants.
posted by Horace Rumpole at 8:46 AM on December 2, 2007

I was given "Arthur C. Clarke's Mysterious World" when I was a kid. I don't recall whether it was in Death Valley or another location, but the same observations were made. I think the ice/wind theory was put forward there, too.
posted by dreamsign at 9:22 AM on December 2, 2007

See also...National Geographic, November 2007
posted by jaronson at 9:35 AM on December 2, 2007

I'm pretty sure it's God. I'ma gonna start a new church. "The Church of the Rolling Stones."
posted by five fresh fish at 10:20 AM on December 2, 2007 [2 favorites]

playa @ night
posted by hortense at 10:21 AM on December 2, 2007 [5 favorites]

A Park Service sign near the car read: "Please do not remove the rocks; they become essentially meaningless when moved out of place."

There are some very cool people working for our National Park Service.
posted by oneirodynia at 11:43 AM on December 2, 2007

I don't doubt that people have taken moving rocks home because they're "magical".
posted by 2sheets at 11:56 AM on December 2, 2007

Any time something happens in the desert and there's no obvious explanation, assume the answer is ice. Someone stabbed, but no murder weapon? Ice dagger. Someone shot, but no bullets? Ice bullets.
posted by Hildago at 12:09 PM on December 2, 2007

The rocks were all named by the original researcher, who's name has now escaped me. They all have female names. (Ex-)Girlfriends?
Paula also teaches a great GIS course at San Jose State University.
posted by agentofselection at 12:41 PM on December 2, 2007

Obviously the rocks are motionless and the planet just moves around them. Duh.
posted by BitterOldPunk at 12:59 PM on December 2, 2007

I don't doubt that people have taken moving rocks home because they're "magical".

Most people associate the 1980 eruption of Mt. St. Helens with producing tons and tons of very fine ash. But if you are right on the mountain, you start getting actual chunks of the stuff that look just like what you might pick up in Hawaii. Consequently the Forest Service posts signs that read "Don't be a pumice picker".

I wonder why no one seems to study the playa's strange process using "control" rocks of uniform shape, density and mass. Heck, why use rocks at all? Would a bowling ball move in the same way? How about a golf club, or a cinder block? How about a starter motor from a 1972 Ford Pinto?

More seriously, why not create "test rocks" that contain electronic telemetry sensors? I'll bet solar panels would work to power them for long term study.

With today's technology, you could embed a motion activated switch into a test rock that would trigger a remotely positioned camera to record when the test rock moved.

What happens if two rocks (or more) are tethered together? Would they move as one, or writhe independently like snakes on Medusa's head?

Lastly, what happens if you corral some of the rocks? Could you coerce them to fight like Battlebots? Or would they just bounce off the walls like pinballs during "multiball"?
posted by Tube at 1:56 PM on December 2, 2007 [2 favorites]

related askme
posted by philomathoholic at 2:40 PM on December 2, 2007

Why not pick pumice? Is there a whole lotta unique life growing on it?
posted by five fresh fish at 5:50 PM on December 2, 2007

Someone shot, but no bullets? Ice bullets.

That one's been Mythbusted.
posted by Kirth Gerson at 3:50 AM on December 3, 2007

Solid! Thanks for the post.
posted by petersn1 at 5:47 PM on December 3, 2007

The answer is the wind, what else could it be! I've seen this story before.
posted by sebastionjacksongallery at 6:50 AM on December 5, 2007

Here is a slideshow by a guy riding a bicycle around DVNP including the racetrack, hard core touring.
posted by hortense at 7:39 PM on December 18, 2007