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Sliding Rocks Bemuse Scientists 433

Posted by kdawson
from the no-footprints dept.
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.
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Sliding Rocks Bemuse Scientists

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  • Mark Newman Poster (Score:5, Informative)

    by stoolpigeon (454276) * <bittercode@gmail> on Tuesday November 27, 2007 @04:41PM (#21496757) Homepage Journal
    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.
    • by An ominous Cow art (320322) * on Tuesday November 27, 2007 @04:44PM (#21496813) Journal
      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.
      • It's very easy to imagine that if the ground had been muddy, the wind could slide the rocks around.

        There are few sights as graceful as the majestic stoneships with their rocky sails gliding across the bounding main.

        OK, I can possibly imagine storm winds so ferocious that they can drag rocks across a rough surface. I just can't imagine said surface being neatly lined and clean-edged afterward. If the mud were soft enough for the rocks to move across it easily, wouldn't it be prone to the soil equivalent of whitecaps with little ripples across it?

    • Re: (Score:3, Funny)

      by clam666 (1178429)
      In soviet desert, rocks move you?
  • by loftwyr (36717) on Tuesday November 27, 2007 @04:42PM (#21496771)
    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: (Score:3, Funny)

      by 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.
    • No Kill I
    • by sokoban (142301) on Tuesday November 27, 2007 @04:52PM (#21496959) Homepage
      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.
  • by explosivejared (1186049) <hagan...jared@@@gmail...com> on Tuesday November 27, 2007 @04:42PM (#21496775)
    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!!
  • by Anonymous Coward on Tuesday November 27, 2007 @04:44PM (#21496809)

    ...nature's version of desert curling?

  • I think that I can safely speak for everyone here when I say, 'WTF?'
  • by foobsr (693224) on Tuesday November 27, 2007 @04:45PM (#21496827) Homepage Journal
    ... 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.
  • Begs the question (Score:4, Interesting)

    by orclevegam (940336) on Tuesday November 27, 2007 @04:47PM (#21496857) Journal
    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.
    • Take MOVIES of the stupid things ... and have devices in view that measure the wind speed and the temperature.

      Also, build a rock with different measuring devices in it and see if IT moves.
    • why hasn't someone setup a webcam to record these rock movements and solve this thing once and for all?

      The reason is because there is no way to know when these rocks, or which rocks, will move. Since we don't currently know what causes them to move, there is no way to wait for those conditions and then start filming. Even with the best guess (wind + water or ice) you'd still have the multi-choice selection of subjects to choose from.

      What would have to be done is to have multiple cameras pointing a

      • Well, I figured it would probably take a year or so of monitoring before you got lucky enough to catch one in the cameras viewing angle, which is why I was thinking webcams that you could just leave there year around. As for stealing it, maybe an enclosure? Plus, I mean, it's a webcam, if someone tries to steal it at least you'll be able to get a recording of them doing it.
        • if someone tries to steal it at least you'll be able to get a recording of them doing it.


          Not if they come up from behind it or wear a mask. Trust me, if there is something to be stolen, someone will figure a way to do it. Take a look at the houses in Detroit (and other places) which are up for foreclosure. People are stealing the siding off of them to be sold as scrap.

      • by fbjon (692006) on Tuesday November 27, 2007 @05:30PM (#21497495) Homepage Journal
        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: (Score:2, Insightful)

      by Maint_Pgmr_3 (769003)
      I agree, if "they" [USGS] can put spiders on MT ST Helens to see how the dome is growing and moving, you would think that someone could tape a small GPS on the rock. Duct tape shouldn't change the movement by much.

      better yet, put a small weather station, ala north pole, on a sled and leave it in the middle of the playa and see what the weather conditions are and when it moves. 12 volt battery and an automotive condenser should discourage people from disturbing the sled.
    • This begs the question, why hasn't someone setup a webcam to record these rock movements and solve this thing once and for all?

      Why not just take some water and a fan up to there to test the leading theory. Wet down a patch of ground to get it nice an slippery and then turn on the fan to see if you can blow a rock around. If that fails then go with the webcam.
    • Re: (Score:3, Insightful)

      by Bob(TM) (104510)
      Yeah, but ... how you gonna keep the webcam from sliding? :)
      • by mdielmann (514750)

        Yeah, but ... how you gonna keep the webcam from sliding? :)
        First you take a stick and pound it into the ground. Then you attach a camera to it.
        If necessary, a traffic light [howstuffworks.com] can be added to increase accuracy.
  • by CitznFish (222446) on Tuesday November 27, 2007 @04:48PM (#21496869) Homepage Journal
    These stones don't want to gather any moss.
    • by spun (1352)
      While we know that rolling stones gather no moss, more research is needed to determine whether sliding stones do. My hypothesis is that they would in fact gather moss, as the same side is always pointing up. Now I'll just need a $500,000 grant to find out for sure.
    • More importantly, don't build any glass houses near here!
  • by egburr (141740) on Tuesday November 27, 2007 @04:49PM (#21496879) Homepage
    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.
    • by Reality Master 101 (179095) <RealityMaster101@noSPAm.gmail.com> on Tuesday November 27, 2007 @04:59PM (#21497079) Homepage Journal

      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.

    • by Evil Pete (73279)

      Yes I noticed too. I also noticed that the rocks pictured were not random shapes. The front of the rocks looking more like a slidable(?) geometry. Perhaps the rocks are not pushing any mud in front of them but riding over it. Too many ifs. We need some observations.

  • The rocks wouldn't by themselves leave such deep impressions and well-developed ridges along the path unless they were moving through mud.
    • by geekoid (135745)
      Except this is old and it's a really thin piece of ice.
      Because there isn't a place windy enough to push a 100 pound rock through a 1/4 inch of mud. SOmething must be lowering the friction AND be thin enough to break.
  • Do the rocks have a large iron content? I wonder how the magnetic fields are in the area...
  • by Culture (575650) on Tuesday November 27, 2007 @04:50PM (#21496917)
    ... 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.
    • Not necessarily. Some kind of localised microtremor could cause the ground to jolt quickly beneath the rock by a small amount. The rock would stay more or less motionless in the Earth's reference frame, while the ground moves quickly beneath it, its frictional forces unable to overcome the rock's inertia. The ground could then settle back to its original place more slowly, this time taking the rock with it.
  • 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
  • by mcg1969 (237263) on Tuesday November 27, 2007 @04:51PM (#21496935)
    is that posting this article in Slashdot is sure to produce a definitive solution to the mystery...
    or rather, 100 of them.
  • welcome our new sliding rock overlords, even though it will likely be a very slow conquest.
  • If there is really this much interest in figuring out how the rocks move, its pretty easy to do. Mount a solar powered camera with a motion detector. If the rock moves start shooting. If you really want to get fancy, you could do a continual time lapse to catch the movement if it is too slow for the motion detector. I think they do this kinda thing when you want to get pictures of wild animals in there natural habitat and the cameras are avaliable at your nearest outdoor outfitter.
    • Mount a solar powered camera with a motion detector. If the rock moves start shooting.

      Logic dictates that they'll then only move at night... :-)

  • FSM (Score:2, Funny)

    by Anonymous Coward
    They were obviously moved by his noodly appendages.
  • The Skeptoid podcast addressed this issue and presented a theory. Most theories have the wind pushing the rocks, but that doesn't make much sense since it's hard for wind to push a big rock a long way without rolling. Skeptoid says the lake is sometimes frozen (we're talking about very shallow water here) so there is a layer of ice thru which the rocks protrude. At this point the wind acts on the whole sheet of ice which has the power to slide the rocks without rolling them.

    Yeah, that or it's space aliens w
    • Another theory that I've heard (which isn't mentioned in this article) is that the daily expansion and contraction of these rocks causes them to inch along. No idea how plausible any of these theories are. Until we set up a camera (including one that can take night shots) and record it, we won't know for sure.
  • It rains. Water freezes into large floating sheets. Sheets are blown around. Rocks move.
  • ...welcome our new geological overlords.

  • by VE3MTM (635378) on Tuesday November 27, 2007 @04:57PM (#21497049)
    Clearly the Flying Spaghetti Monster is moving them with his Noodly Appendage.
  • Sorry guys, but I personally don't have to see a photo in the far-octarine to tell that these are your average, semi-bored trolls. They will obviously just look like rocks to the untrained eye during daytime, but they are no puzzle to someone who's been around the disc...
  • by sunking2 (521698)
    Stupid scientists. It's the Graboids doing it. And Kevin Bacon HAS seen them.
  • From our friend wikipedia [wikipedia.org] we learn: "Professor John Reid led six research students from Hampshire College and the University of Massachusetts in a follow-up study in 1995. They found highly congruent trails from stones that moved in the late 1980s and during the winter of 1992-1993. At least some stones were proved beyond a reasonable doubt to have been moved in ice flows that may be up to half a mile (800 m) wide. Physical evidence included swaths of lineated areas that could only have been created by movi
    • Re: (Score:2, Funny)

      by sunking2 (521698)
      Hampshire college. Can we look for an explanation that didn't come about from smoking massive amounts of dope in the middle of the desert.
  • I sense that there are some tax dollars at work, or soon to be at work on this very question! Perhaps we could have the government fund a study to watch these rocks, observe them 24 hours a day, 7 days a week, 365 days a year, record their activity, and uncover the truth! It's for science! ;-)
  • ...it is the earth that is moving underneath them. Perhaps there is enough of a lift by a small mud sheet that the rotational forces of the earth allow the rocks to slide on top.

  • There's obviously a runaway solution in the differential equation governing that part of the Matrix.
  • One possibilty (Score:5, Interesting)

    by edwardpickman (965122) on Tuesday November 27, 2007 @05:15PM (#21497299)
    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.
  • by scubamage (727538)
    This is really cool actually. My guess would be high wind, tied with a low friction surface. Long flat stretches of land tend to equate to massively strong winds. The ground is bone dry, so I'd guess that adding water is going to first add a layer of water that the rock would travel on, and not so much the ground itself. As the water begins to soak into the ground the rock will face more and more resistance because its traveling on progressively more silt and clay than water. Has anyone seen any arial phot
  • by SmallFurryCreature (593017) on Tuesday November 27, 2007 @06:21PM (#21498075) Journal

    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?

1: No code table for op: ++post

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