Sliding Rocks Bemuse Scientists

An anonymous reader writes "Scientists can't figure out why these rocks — weighing up to several hundred pounds each — slide across a dry lake bed. The leading theory proposes that wind moves the rocks after a rain when the lake bed consists of soft and very slippery mud.

Mark Newman Poster

[stoolpigeon (454276)]

Mark Newman [art.com] has a very nice sliding rock poster [amazon.com] with a good shot of rock and trail in a variety of sizes.

Re:Mark Newman Poster

[An ominous Cow art (320322)]

I was there in August this year, and it was quite windy. It's very easy to imagine that if the ground had been muddy, the wind could slide the rocks around.

Re:Mark Newman Poster

[stoolpigeon (454276)]

In the desert the ground is really, really hard. It is completely plausible that a thin layer on the top could be slimy mud, while hard clay lies beneath.
 
I don't think you appreciate how remote this site is and what an effort it would be to pull off something like that. I really don't think it is someone messing around or that the wind theory is as unlikely as you think.

Re:

[ChameleonDave (1041178)]

Indeed.

When my heavy beer glass gets a tiny bit of water between it and the hard table, it starts sliding around all by itself, with no wind at all. I can imagine that these stones slide similarly.

Re:Mark Newman Poster

[Basehart (633304)]

It's not just beer. I was bathing the other day and my pint sized glass of heavily iced water all of a sudden moved across the smooth plastic surface of the toilet seat lid and fell to the floor.

The toilet seat lid was covered in a fine layer of condensation from the bath water at the time.

I'm betting if the stones are cooled way down to almost freezing by the wind, or maybe frozen overnight and still cold when the rains hit, and the top surface of the mud turns into a slurry of fine particles, the stone will move around all on its own just like my cold glass of water on a fine layer of condensation.

Either that or space aliens.

Re:Mark Newman Poster

[vought (160908)]

Just seems to me that instead of crazy rocks sliding round on their own, some damn kids were up there fucking round with rocks.

Considering how difficult it is to get out to the Racetrack, I doubt this. Otherwise, I would think someone might camp out there during a storm and find out if they really skate around on their own.

Problem is that storms come up rarely but suddenly there (usually) and it takes almost two hours to get to the Racetrack from the nearest paved road - three hours from the Death Valley visitor's center - and if you get out there before a storm, there's no guarantee that even a very capable 4x4 will get you back afterwards.

Re:

[Roger W Moore (538166)]

Problem is that storms come up rarely but suddenly there (usually) and it takes almost two hours to get to the Racetrack from the nearest paved road - three hours from the Death Valley visitor's center - and if you get out there before a storm, there's no guarantee that even a very capable 4x4 will get you back afterwards.

Isn't this what remote camera's were invented for? I doubt this location is so remote that there isn't some way to link it up or at least to store the data and then periodically retriev

Re:Mark Newman Poster

[vought (160908)]

It sounds like fun, and it would only take a few years to get results. Compared to raising children the cost is low and the results are fast.

I agree. You do it.

Re:Mark Newman Poster

[radish (98371)]

Yeah, I mean heaven forbid tourists actually come and spend money at their tourist-related businesses. I can imagine they're so glad when all that money goes back where it came from! Then their hotels can be nice and empty like they should be.

Re:

[MillionthMonkey (240664)]

I love places that try to require a tip on the bill. Those places, shoudl I happen to wind up at one unknowingly, will never get a cent for a tip. I'll figure out the actual check total and pay exactly that. The can go scratch on the tip for being retarded about it.

In Death Valley? They'll remember your face and tomorrow you'll end up driving an extra 50 miles for lunch.

Re:

[clam666 (1178429)]

In soviet desert, rocks move you?

It's a Horta!

[loftwyr (36717)]

I saw this on TV once! It was this documentary about these very things! They're called Hortas and their intelligent. Apparently they can be taught to mine.

Re:

[iggymanz (596061)]

you also don't want a female Horta to sit on your face if you wear glasses, that hydrofluoric acid they secrete when they're horny eats right through spectacles.

Re:It's a Horta!

[xSauronx (608805)]

Sit on my face, and tell me tha--- Oh god my eyes... THE BURNING! it burns so bad!

Re:It's a Horta!

[jfdawes (254678)]

.... the goggles ... they do nothing ....

Re:

[jamstar7 (694492)]

So many great setups, so few modpoints.

Re:It's a Horta!

[sokoban (142301)]

Yes, and though the flow of water surrounding these things can be directed, these Horta do not readily absorb moisture.

Thus, you can lead a Horta water, but you can't make it drink.

Re:

[dfn_deux (535506)]

The Horta culture is really complex like that ;)

Re:

[camperdave (969942)]

Plant a camera out there for a year, take a snapshot every minute (or use motion detection), collect weather data (humidity, dew point, temperature, evaportion rates, wind speed/dir) and corrolate that to the time-series snap shots.

... and hopefully you'll be able to find out who made off with your expensive camera.

Re:It's a Horta!

[hazem (472289)]

Easy! You just put a camera to watch the camera...

I wonder if they can just "tag" the rocks like they do with sharks, elephants, walruses, etc. I mean, I know the rocks don't have ears or collars, but there has to be a way.

Re:

[Carnildo (712617)]

There are a number of reasons why they haven't:
* The rocks don't move very often -- typically once every two or three years.
* Cheap webcams have only been around for a few years, and I don't know if there have been any movement episodes during this time.
* It's an incredibly hostile environment for electronic equipment: surface temperatures of 150+ degrees F during summer days, temperatures below zero F during winter nights, violent rainstorms, and intense direct sunlight.
* There is no electricity. There is

Re:It's a Horta!

[vought (160908)]

Given the hottest temperature ever recorded in the United States is 56.7 degrees celsius (134.1 degrees fahrenheit) I find it impossible to believe this small part of America regularly gets temperatures of above 65.6 degrees celsius (150F).

A friendly nitpick: surface temperatures on the desert floor - even on light-colored surfaces like the Racetrack - can often rise above 200 degrees F. Note that the ambient temperature may be far cooler than the ground surface.

From a dependable source [pbs.org]:

In the heat of summer, Death Valley roasts in temperatures greater than 120 degrees, cool when compared with the surface temperature of the salt pan. "The ground temperature gets to over 200 degrees [f] at some points here," says Dr. Douglas.

I'd wager that the surface temperatures at the Racetrack in early afternoon during high summer range above the boiling point of water at sea level*, since the racetrack's playa is lower and darker than the salt pan at Badwater. In other words, don't fall; you'll skin and burn your knees.

If you've never been to Death Valley in the summer, you should give it a try. If you're from a mild climate, I suggest March instead; the regular 90 degree temperatures before April has shown it's face will give you a little idea of the radical heat that this region experiences.

*The Racetrack and Badwater are both below sea level, so you'd need to get up to at least 240f to boil water.

Re:It's a Horta!

[martinX (672498)]

They won't move if they know they're being watched.

Obvious Answer!!

[explosivejared (1186049)]

Anyone who has seen an M Night Shamylan movie or been involved in a Usenet discussion about UFO's can readily see that there is one glaringly obvious answer...

IT'S ALIENS GUYS!! RUN FOR YOUR LIVES!!

So this is...

[by Anonymous Coward]

...nature's version of desert curling?

Answer on page 42 ...

[foobsr (693224)]

... literally:
Quote: "Research of the Racetrack has continued. In the April 1997 GPS World, Paula Messina, Phil Stoffer and Keith C. Clarke reported a GPS study they conducted of the Racetrack. In ten days of intense field work they mapped every featured of the playa using differential GPS to produce, "the first-ever, complete, georeferenced, submeter-resolution map of the wandering rocks." (Messina, 1997, p. 42)"
http://sophia.smith.edu/~lfletche/deathvalley.html [smith.edu]

But it seems they have no real conclusion too.

What about 'The Force"?

CC.

Re:Answer on page 42 ...

[orclevegam (940336)]

GAH! MY EYES!!! Put a warning on that link, geez.

Begs the question

[orclevegam (940336)]

This begs the question, why hasn't someone setup a webcam to record these rock movements and solve this thing once and for all? I mean, if they can setup cameras in the arctic circle, death valley shouldn't be that hard to handle.

Re:

[Bob(TM) (104510)]

Yeah, but ... how you gonna keep the webcam from sliding? :)

Re:Begs the question

[fbjon (692006)]

It still seems strange. The place is really dry, meaning there's lots of sun. Just make a small package with a GPS receiver, some simple weather instruments, a radio uplink to a nearby relay, a small camera and a solar panel with battery. If the GPS detects any movement, or the weather instruments detect any drastic changes, turn on all other stuff and start piping data to the relay, which passes it on by whatever means.

If anybody steals the package, it'll sound an alert and record who took it, and where they're taking it.

Re:

[Random Destruction (866027)]

I'm siding with Paul Brians on this one.
http://wsu.edu/~brians/errors/begs.html [wsu.edu]

Raises the question != Begs the question.

Isn't it obvious yet?

[CitznFish (222446)]

These stones don't want to gather any moss.

no buildup in front

[egburr (141740)]

In all those pictures, I don't see any buildup of dust in front of the rocks, though there is plenty on the sides of the paths. Usually, when I push something through the dirt/mud/snow/whatever, I end up with a good buildup in front, too. I wonder where that has gone.

Re:no buildup in front

[Reality Master 101 (179095)]

In all those pictures, I don't see any buildup of dust in front of the rocks, though there is plenty on the sides of the paths. Usually, when I push something through the dirt/mud/snow/whatever, I end up with a good buildup in front, too. I wonder where that has gone.

I had to think about this for a second... I think the answer is that if a rock was digging into the mud, you wouldn't have this effect, because of having to shove the mass of the mud. If you look at the pictures, the fronts of a lot of them tend to be sticking up, implying they're "surfing" over the mud.

I am pretty sure ...

[Culture (575650)]

... that the rocks slide because the lateral forces exerted on the rocks exceed the static and dynamic frictional force cause by the gravity induced weight of the rock acting across the mud-rock interface. I guess I could be wrong and there are worm-holes involved.

god doesn't play dice

[circletimessquare (444983)]

but he does hold magnets under the surface of the table, moving objects on top as if by magic, just to bemuse and entertain us

One thing I know for sure

[mcg1969 (237263)]

is that posting this article in Slashdot is sure to produce a definitive solution to the mystery...
or rather, 100 of them.

Silly scientists...

[VE3MTM (635378)]

Clearly the Flying Spaghetti Monster is moving them with his Noodly Appendage.

One possibilty

[edwardpickman (965122)]

I'd be curious if the under sides of the sliding sliding stones were concave? Why I mention it is I still remember a certain chinese restaurant's tea cups had a habit of sliding across the table. The table tops were resin coated and the concave cups tended to capture moisture under them so when the tea heated the moisture under the cup the expansion provided enough lift to break the friction and allow them to slide. They would move randomly in different directions then stop for a few minutes then slide again. Since the area is hot a unique combination of heated rocks with slippery mud and wind could in combination cause the effect. I remember that some rocks slid and others didn't as well as the direction changes.

Problem with the ice or even water theory

[SmallFurryCreature (593017)]

The cracked effect is what you get when muds dries out, the effect is NOT visible in the trails. How can this be IF the rocks moved when the mud was still there? There is a cracked effect in the trail but it is crushed, the effect you would expect if the rocks had been moved AFTER the ripple effect had already started to form, AFTER the mud started to dry or even when it was already dry.

But if the rocks moved on ice then AFTER the ice melted there would be mud, that if dried would show the same pattern all around the newly positioned rock with just the ridges of the trail left. NOT flattened dried mud.

As for purely the wind moving them, how fast do the winds get there anyway? Wind can be extremely powerfull even in areas with lots of obstructions, in open areas, well if it can pick up/move trucks, why not rocks? Far heavier things are lifted up by air alone, how do you think aircraft work?

Re:Any word on magnetic influence?

[$RANDOMLUSER (804576)]

Actually, it's caused by the continential tilt. It causes all the loose cannons and nuts and bolts to roll towards California.

Re:Any word on magnetic influence?

[TempeNerd (410268)]

Obviously, the rocks were casually lurking on Slashdot, when they read "Move along, nothing to see here..."

{rimshot}

Everything must be ruled in or out, but...

[ackthpt (218170)]

Re:Any word on magnetic influence? I'd guess it isn't wind...are these rocks ferrous? Or...maybe the earth is tilting on its side...weird stuff like that always happens here...I think our perspective of it is just off a bit.

I've camped a few times at Texas Spring campground in Death Valley. Nice place in the right times of the year. One year, however, the wind blew all night at about 40 knots. Nearly took me and my tent away. There are sand dunes to the north of the valley, too. I expect the winds there are more than up to the task of pushing around rocks on moist clay. Perhaps most enigmatic is the question, 'Why don't these larger rocks sink into the mud?' Though with strong enough winds, I imagine they could get a

Re:Magnetism?

[Rob T Firefly (844560)]

Do the rocks have a large iron content?

I hope not. If there's one thing I can't stand, it's ironic rock.

Re:Magnetism?

[spun (1352)]

Ironic rock is worse than rai-e-ain on your wedding day, or a free-ee ride, when you already paid.

Re:Global Warming

[AlamedaStone (114462)]

because teutonic plate theory was just too crazy to accept...
 
... although it replaced the even more silly Gaulish plate theory, quickly discarded by history.

Re:

[Ambiguous Coward (205751)]

Come now...while I agree that the video is (mildly) interesting, it is not what you claim. But beside that, the article doesn't say "there's no possible explanation" at all. In fact, the article presents at least a couple possible explanations. In fact, and I say this with every ounce of *gasp* I can muster, the article presents an explanation for the moving rocks that is identical to the one presented in the video! Did you happen to read the article? You ought to. It's relevant to this discussion.

-G

Re:Amazing how no-one bothers to actually CHECK.

[DigitalCrackPipe (626884)]

In true /. form, you either failed to RTFA or to WTFV, as the video clearly does not show the rocks moving. It shows water and miscelaneous floating scum moving, and posits the same theories as in the article (just claiming them to have been proven).

And as to the foolishly simple explanation, H.L. Mekcken is quoted to have said, "Every complex problem has a solution that is simple, direct, plausible, and wrong".

Re:Amazing how no-one bothers to actually CHECK.

[evanbd (210358)]

Did you watch the video carefully? They offer a very authoritative sounding explanation of the water / ice theory presented as one option in the article, but don't actually capture rocks in motion on film. There's water moving, and some sort of foam on top of the water, but that's about it. As the original article says, there's lots of evidence in favor of this theory, but also evidence against it being that simple -- like experiments involving undisturbed stakes and such. As far as I can tell, that seems to be a piece of the explanation, but not the whole explanation.

That was Strangely Topical.

[Smordnys s'regrepsA (1160895)]

Rick Rolled while Reading about Rolling Rock Research, by a link Represented as Relevant.

I Require you Rectify this Rankling Repugnance.


Regards,
Ryan