Life in Death Valley
The Mystery of the Racing Rocks

It is one of Death Valley’s most intriguing geological whodunits — the sliding rocks of the Racetrack Playa.

On an ancient lakebed located on the western side of Death Valley National Park, boulders that weigh up to 700 pounds sail across the almost perfectly flat terrain, leaving grooved trails in their wake. As NATURE’s Life in Death Valley shows, each of these furrows chronicles a rock’s journey, ranging from a mere few inches to nearly 3,000 feet. Some tracks manifest in straight bold lines, while others coil back on themselves in sinuous arcs.

Despite a century of scientific investigation, this curious phenomenon has confounded the geological community and park visitors alike. To this day, no one has ever seen the rocks move. But in lieu of eyewitnesses, countless theories have been put forward over the years in an effort to explain the reasons behind the migrations.

One early suggestion was that the rocks were driven by gravity, sliding down a gradual slope over a long period of time. But this theory was discounted when it was revealed that the northern end of the playa is actually several centimeters higher than the southern end and that most of the rocks were in fact traveling uphill.

Though no one has yet been able to conclusively identify just what makes the rocks move, one woman is coming closer to solving the mystery. For the past ten years, Dr. Paula Messina, professor of geology at San Jose State University in California, has made it her quest to understand what has bewildered geologists for decades. “It’s interesting that no one has seen them move, so I am kind of sleuthing to see what’s really going on here,” says Dr. Messina.

Many scientists had dedicated much of their careers to the racing rocks, but the remoteness of the area kept their research limited in scope. No one had been able to map the complete set of trails before the advent of a quick, portable method known as global positioning. Dr. Messina was the first to have the luxury of this high technology at her fingertips.

In 1996, armed with a hand-held GPS unit, she digitally mapped the location of each of the 162 rocks scattered over the playa. “I’m very fortunate that this technology was available at about the same time the Racetrack captured my interest,” she says. “It took only ten days to map the entire network — a total of about 60 miles.” Since then, she has continued to chart the movements of each rock within a centimeter of accuracy. Walking the length of a trail, she collects the longitude and latitude points of each, which snap into a line. She then takes her data back to the lab where she is able to analyze changes in the rocks’ positions since her last visit.

She has found that two components are essential to their movement: wind and water. The fierce winter storms that sweep down from the surrounding mountains carry plenty of both.

The playa surface is made up of very fine clay sediments that become extremely slick when wet. “When you have pliable, wet, frictionless sediments and intense winds blowing through,” offers Dr. Messina, “I think you have the elements to make the rocks move.”

At an elevation of 3,700 feet, strong winds can rake the playa at 70 miles per hour. But Dr. Messina is quick to point out that sometimes even smaller gusts can set the rocks in motion. The explanation for this lies in her theory, which links wind and water with yet another element: bacteria.

After periods of rain, bacteria lying dormant on the playa begin to “come to.” As they grow, long, hair-like filaments develop and cause a slippery film to form on the surface. “Very rough surfaces would require great forces to move the lightest-weight rocks,” she says. “But if the surface is exceptionally smooth, as would be expected from a bio-geologic film, even the heaviest rocks could be propelled by a small shove of the wind. I think of the Racetrack as being coated by Teflon, under those special conditions.”

In science, hypotheses are often based on logic. But over the years, Dr. Messina has discovered that on the Racetrack, logic itself must often be tossed to the wind. “Some of the rocks have done some very unusual things,” she says.

In her initial analysis she hypothesized that given their weight, larger rocks would travel shorter distances and smaller, lighter rocks would sail on further, producing longer trails. It also seemed reasonable that the heavier, angular rocks would leave straighter trails and rounder rocks would move more erratically.

What she discovered surprised her. “I was crunching numbers and found that there was absolutely no correlation between the size and shape of the rocks and their trails. There was no smoking gun, so this was one of the big mysteries to me.” What appears as a very flat, uniform terrain is in fact a mosaic of microclimates. In the southeastern part of the playa, wind is channeled through a low pass in the mountains, forming a natural wind tunnel. This is where the longest, straightest trails are concentrated. In the central part of the playa, two natural wind tunnels converge from different directions, creating turbulence. It’s in this area that the rock trails are the most convoluted. “What I think is happening,” proposes Dr. Messina, “is the surrounding topography is actually what is guiding the rocks and telling them where to go.”

Some people have suggested attaching radio transmitters to the rocks or erecting cameras to catch them “in the act” in order to put an end to the speculation. But as Death Valley National Park is 95 percent designated wilderness, all research in the park must be noninvasive. It is forbidden to erect any permanent structures or instrumentation. Further, no one is permitted on the playa when it is wet because each footprint would leave an indelible scar.

As for Dr. Messina, she is content in the sleuthing. “People frequently ask me if I want to see the rocks in action and I can honestly answer that I do not,” she says. “Science is all about the quest for knowledge, and not necessarily knowing all the answers. Part of the lure of this place is its mystery. It’s fine with me if it remains that way.”

  • logical dude

    ummmm…. a time-lapse camera????

  • humble observer

    Dear Logical Dude,

    In case you missed this part of the above article…

    “Some people have suggested attaching radio transmitters to the rocks or erecting cameras to catch them “in the act” in order to put an end to the speculation. But as Death Valley National Park is 95 percent designated wilderness, all research in the park must be noninvasive. It is forbidden to erect any permanent structures or instrumentation. Further, no one is permitted on the playa when it is wet because each footprint would leave an indelible scar.”

  • Davy

    I wonder if there’s also not some hydraulics involved. Presumably water is being pushed around on the playa as well. Might that create some kind of sucking force on the rocks? I like the teflon analogy as well. Even I can push around a heavy boulder over ice. And don’t forget Newton; objects in motion tend to stay in motion absent any resistance. Very curious.

  • michael

    how about when it is dry to place a small gps system on all the rocks to prove that they move

  • Tim Dalbey

    I have researched pans (playas) in the Karoo of South Africa and I have had a similar problem where large dolerite (basalt) boulders (50 x 50 x 50 cms and greater up to 0.5 cu. m) out in the middle of one flat surface pan in particular. I have no modern day trail as at Racetrack Playa. Any modern day trail would be obliterated by weather conditions shortly after they would appear. The large boulders at this pan arrived at some time in the distant past, however smaller cobbles and small boulders may still be moving. This one particular pan is about 0.70 sq. km in size, not nearly as large as “Racetrack Playa,” but possibly the same forces as work. I have no definite answers just hypotheses an empirical observations. The elevation of the pan (Haaskraal Pan Complex, HPC) is approximately 1,478 masl (4,850 ft. asl), and is in an arid area that receives 100m to the center over a flat surface.

    At first I thought that the floodwaters from the stream played some role in moving the boulders. I excavated cross-sections of the stream channel, terrace deposits south of the pan, and walked up and down the exposed stream banks but did not find any boulders approaching the sizes of the boulders on the pan surface. There were no boulders in the upper stratigraphy of excavations of adjacent terrace deposits outside of the pan that in the past were above today’s pan surface indicating deflation of the terraces and the pan surface. In the upper layers of one terrace deposit I found convoluted drainage patterns indicative of frozen ground.

    A combination of physical occurrences combined to move these large boulders. In a rather fast flip flop of weather conditions cold dry late Pleistocene conditions with frozen ground gave way to saturated montmorillonite sediments as convoluted patterns began to thaw, combined with heavy prevalent northwest winds and high rainfall that made the boulders move slowly toward the center of the pan. Repeated drying and large dessication cracks on the surface followed by high winds and the right amount of moisture from rainfall moved the boulders over the slick clay surface additionally over time.

    From Antarctic ice cores during the late Pleistocene ca. 25-35 kyr there were frequent cold/dry conditions followed by wet/warm conditions during this period. This may be the time when the boulders moved. It seems the Racetrack Playa boulder paths are more current, but is there any evidence for these pathways in the past? What is the mineralogy of the soil? Do dust devils occur? How much patination occurs on the boulder surfaces? How embedded in the surface are the different boulders? I find this an intriguing problem. A waiver and permit from the Park Service to study the problem in a minimalist invasive approach worked out with them through their permit process would seem possible and should be attempted. Believe it or not this is a sedimentological scientific problem that occurs in various parts of the world that needs further research.

  • Kingston Hugh Middleton

    someone needs to walk out there without permission at the edge fo the mountian side with a high zoom time laps camra and leave it there all camo like and come back one week later and see if the 700 lb. roock moved if the tripod legs of the camra “scars” the land so be it it’s in the act of science then u can go back to your computer and see if it moved.
    i think magnetic pulls have something to do with it but a camra will see the forces acting on it.

  • Lance Sievert

    The answer, I believe, is that the Playa stones do not actually move but rather the earth moves under them. The Playa surface is flat and riddled with “viens”, providing reduced resistance in the form of “drag.” The more important force at work here is Magnetic Fields. The rocks have a magnetic field which may have become polarized upon formation or by a electrostactic fields generated by friction or by laying in the same position in relation to the earth’s magnetic field for eons coupled with repeated cycles of extreme heat and cooling. Even moderately polarized material of the smallest size are “acted upon” my the Earth’s magnetic field, by aligning itself with the magnetic poles of the earth or in this case retaining a certain “sweet spot” where the magnetic field of the Earth exercizes a greater force on the stones than does the friction of the soil that the stones are “defying.” The soil, most likely “flows” around the rock much the way water does but without the ripples.

    This can be demonstrated by lightly covering a paper plate with sand, sugar, flour or actual soil about 1/16″ deep. Carefully shake the plate back an forth while holding it level to create smooth horizontal “Playa” surface.

    Gently place your “Playa Stone,” (a small piece of iron, metal or a magnet,) atop the “soil.” Finally, take a magnet and hold it under the plate directly below, but not in contact with your “Playa Stone.” Holding the magnet in place, pull the plate horizontally in only one direction. Your “Playa Stone should have created a trail through your “soil” much like the above picture.

    This may or may not be what is happening in Death Valley.

    Additionally, I propose that if it is the case that magnetic fields are working to hold the stones in place, the tracks have and will again stop and then change direction as the Earth’s magnetic field changes over time.

    It may also be that Playa surface has a very slight incline and that seismic activity of the right magnitude is creating vibrations which act upon larger solids more intensely by transfering that vibrational energy into the solid which uses that energy to vibrate as well, gravity comes into play pulling the stones down the incline as they vibrate.

  • Lance Sievert

    The theories of Dr. Paula Messina which include wind water and bacteria do not hold true

    Have you ever seen wind blow even a small piece of gravel across a road, sidewalk or even ice. If it were water that was causing the movement, the raised “wake” of the soil, (pictured above,) left on either side of the stone’s trail would wash away when created.

    Additionally, wind is not constant either in intensity nor direction. The change in direction and intensity of the wind would serve only to keep the stone in place, as all efforts over time would not amount to a consistant direction.

    As I proposed above, magnetic fields would act on the stones equally despite the size or shape of the stone. The stones are not moving, the Earth is moving under it, so all trails should be basically uniform. The rocks should all move the same distance and the trail should be constant in the distance of it’s cross-section.

  • Mark Berger

    I have spent quite some time trying to get people to listen to my theory, and I am getting somewhat frustrated. The simple fact is that the rocks are sliding downhill. I know that observations by many individuals suggest that the rocks are moving uphill, but those observations are not being made while the rocks are moving. The quite common phenomena that is responsible for the movement of the rocks is frost heave, and ice lens formation. The rocks are NOT sliding uphill, they are sliding downhill along with the surface layer of the playa. As the weather warms, and people make their observations, it would appear as though they are sliding uphill, but the surface has settled back with the melting of the lenses leaving the Southern end of the Playa lower. This is a somewhat simplistic explanation, but I doubt that anyone is going to pay attention anyway.

  • Mark Berger

    I KNEW that noone would pay attention to this. Unfortunately, for the scientific community, this is the actual answer to this mystery. There is far too much evidence in my favor to argue otherwise.

  • marcos

    I’d thought that the stones skate, when the playa bed is frozen solid from cold core storms and a warm core storm come in and melts the upper layers of mud. The combination of storm wind, ice substructure and silty surface is why they move. I’d bet much movement would be in years with strong warm core storms following cold storms.

  • Mark Berger

    The surface of the playa does not have to thaw or be melted in order for the rocks to move. The surface of the playa may experience sublimation, leaving the rocks free to move. The underlying layer of ice does explain why the stones, no matter what size they are, leave a uniform depth of track. However, if there is an underlying layer of frozen soil, there almost certainly is ice lens formation because the soil type of the playa is highly conducive to this phenomenon. The point I am trying to make is that the surface of the playa is dynamic as opposed to static.

  • george

    A satellite that can be dedicated for awhile in the area would be able to show the phenomena. Why not drive out each day and night in shifts until the movement is captured on camera. I like logical dude’s thoughts on the issue and also think about it being much less intrusive to nature by placing a camera out there rather than all these people driving out there on a daily basis polluting the area! Come on guys, think about it. Perhaps a researcher would be granted a special permit; it’s been done b4.

  • Steve Griffith

    Here it is! I saw a rock in Phenix city, AL move and here is how it’s done. The rock has a flat bottom as the Playa rocks in Death Valley. When a storm or ground water comes the water flows to the front of the rock that is facing the mountain or bluff runoff water. The silt and heavy clay material gets washed underneath the front of the rock creating a opening from the front bottom of the rock continually washing away ever so slowly. This seadament is pushed to the sides of the rock. Then as the weight of the rock loses it’s support , the build up of silt and clay is about 3/4 of the way to the underside and back of the rock making the rock slide forward and then the process starts again and again until the rock reaches some resistance the travels in a new direction. The more rainfall or snow melt coming off the mountain or bluff moves the rocks faster. That’s my take on this and I’m sticking to it!

  • Steve Griffith

    Sorry Mark Berger, Your Theory is incorrect but I feel your pain as it is hard to get anyone to listen. All other scientist a wrong also. Guess you need a PHD in science to figure this one out! If you look at the rainfall history and Dr. Messinas GPS charts she has posted on the web, you can see the years with more than 2.3 cm of rain the rocks moved. At other times with little rain there was no movement. 1. All these rocks have a flat surface on the bottom 2. all are moving up hill 3. water runs downhill as H20 travels were there is least resistance. 4. when playa is wet the mud/silt is about 1 inch deep 5. hard clay is under the mud/silt 6. sometimes you need to get outside the box 7. learn to listen with your eyes!

  • bryan

    hey mark, how about no. if they were sliding downhill, then they would’nt stop and change direction in a 90 degree fashion. Your entire post is incorrect because you fail to realize they dont just move in one direction, they move in all kinds of directions, and stop and do 90 degree turns. Sorry, maybe next time.

  • Jim

    “People frequently ask me if I want to see the rocks in action and I can honestly answer that I do not,”

    Of course, that would erase your claim to fame and most of your body of published work. You do not want to find the answer? egads

  • http://nolimitleads.com

    Thanks to you for this great info. Where I can get more information about this writting? I have a panel discussion incoming this week and your writting is related with it.

  • Mattis Piegat

    I think that during winter nights arround the stones frost makes the ice table, and this few square meters is enough to move the stone by the light wind : 10 mph.

  • Marco

    Racetrack Playa is possibly the most spectacularly otherwordly place I’ve ever been. In that context, as remarkable as they are, the walking stones didn’t even seem that particularly strange.

    If it is ever conclusively proven how the stones walk it would probably be interesting and little more, (unless some environmentally earth changing energy source was discovered). What I find essential, is that humans experience places like Death Valley & Racetrack Playa to feel the overwheliming tinyness and insignificance of human concerns.

    With that perspective, perhaps we can re-orient our species from competition to cooperation. But heck, I’m just a ski bum, not a scientist.

  • Allen

    The hypothesis of the lady scientist could indeed be true but other unseen forces could also be at play. Every thing in existence has a molecular structure constantly in motion. It’s too bad that scientists don’t have access to more information that could solve the mystery because it could open unseen doors to the forces of nature at work. I wonder if anyone has ever tested the area for electromagnetic fields in relationship to the mineral composition of the rocks/boulders in question? Spectrographic analysis would suffice. Just another idea but the last word is ” why explore other worlds & planets when we don’t even know or understand our own yet?”

  • Laura B

    How invasive could a small camera be? REALLY. Considering the decades of research that has gone into this….it seems just ridiculous. I’ve loved the valley my whole life — lost count of the times I’ve visited…..so I don’t say this out of a lack of respect for its welfare. Death Valley was an active mining area — in some parts — well into the 70s, and still has an active licensed mine operating within its boundaries. So it’s OK to extract ore, but not set up a few web cams? It seems absolutely ludicrous…and makes me think there *must* be another reason….something associated with the actual ability of the cameras/transmitters to properly operate (cell phones won’t in a lot of the park due to iron content I believe)….I’d really like to know. Maybe they just like the “mystery” hype. Bonnie Claire Playa nearby (Nevada) also has a bi of a ‘racetrack’…..wonder if anyone’s though of setting up there?

  • Jon

    Of coarse I think the real question here is who really cares? Figuring this will help create jobs how? Stop famine how? What is nuts is someone spent years figuring this (well nothing) out. I hope no taxpayers money was wasted on this case of mental masturbation.

  • Connie Scott

    I believe between the water the moon, the earth, that magnetic attraction is in play and causing the rocks to move.

  • Jon

    Science is all about the quest for knowledge, and not necessarily knowing all the answers. Part of the lure of this place is its mystery. It’s fine with me if it remains that way.”

    There it is in her own words. Basically she is pursuing a goal that it matters not a wit if she achives it. Only that she pursues it, and others are in awe of her. This kind of pursuit paid for by taxpayers via federal grants must be a wonderful career for those whose chose it. (Not sure if she did but be assured many do and for just as useless knowledge) Again I ask with all that needs to be figured out, why bother with this? But I guess it beats a real job, and if you set your sights as low as her above quote you can’t fail.

  • John Kelly florida

    Not really a comment but a question. if it’s wind then why don’t we see ripples in the clay surface also?

  • Linda Royo

    I think her theory of wind, water, bacteria are sound. But why is the trail so “marked” in that the particles are bunched up “showing” a trail? And then fresh footprints doing the same?

    Everything looks so fresh. I would think wind and water would sweep away the trail marks at the same time. They are as fresh as the footprints that just visited.

  • GreatRewards

    Wind? No. Magnetic Fields? No. Frost Heave? No.

    You’re all wrong. It’s aliens. How many of us have enjoyed torturing a cat with a laser pen? Mr. Cat does not understand of the source of the light, or the cause of it’s movement, but he chases it ceaselessly, nonetheless. In this case, WE are the cat, and the aliens are “messing with us”.

    And what a laugh they are having. :)

  • tree

    I find it so wrong when the Dr. Messina says that she doesn’t care to know. As a fellow scientist, I do want to know. Yes there is beauty in mystery, but science is about figuring out the mysteries. We probably won’t figure out all of them, but we can try.

  • Omnipotent Being

    The stones are obviously being carried by microscopic dessert ants

  • John

    I dont think this can be a magnetic field effect. Magnets exert force if AND ONLY IF there is a gradient (a continuous change) in field strength. In uniform magnetic fields, which is the case given the scale of these rocks compared to the size of the earth, all magnetic fields can exert is torque, no work can be done. This is why compass needles dont slowly bend their balance toward north. I cant say anything about any electro-static forces but i do not think this could be caused by magneto-statics.

  • Lil Ol’ Me

    My theory is something along the lines, if you were put a beach chair at the edge of the ocean and you sit in said chair with your feet in the sand, when the water rushes up around your feet and then resides back to the ocean you can see a “trail” where the water eroded the sand from around your feet. This would somewhat explain how the rocks are “traveling uphill” I’m not a scientist by the traditional definition, I just enjoy the sciences. If I’m wrong, please tell me and explain how. I look forward to the responses!

  • just me

    i have no idea of how this happens there, but it does remind me of how as a kid my dad would take us to florida and in some places one could stop the car and turn it off. it would still move uphill a small ways. so maybe what ever causes that is at play there? but really if it was that simple the scientists would have already figured it out. just thought i would put my thoughts out there to. i have not thought of those places in florida for decades.

  • Oklahoma J. Hill

    I’d say alot of really smart people here. Just to dumb to research anything. Just a bunch of guessing. You need to start with the birth of Death Valley range. I’ll let ya’ll smart guys out there figure on it, while my dumb red-neck farm bred boy goes on out back and watch a Toronader slide a rock crossin ma pond.
    You have to take a peek-see overn dere on da otta side of da fence. See ole Ralph has this pig that wollers in the mud. and damnin he dont get into that thang them people on the coast a.do, Oh, Piggy Wallerin, That be it.
    Wel’n one winter long come a nasty blizzard that left 2.5′ snow there in the lower plains of ma back yard. Naw ole Ralphs a boar “8 Ball” as mean as the devil himself. Just to darn dumb to headin for shelter. Heard a Ralph out’n there just for the storm a settled in just a cursing and whoppin on ole 8 Ball. Ralph, soon gave up to roost his yard birds. Left Ole 8 Ball to fiend for himself.
    Come next mornin, I heads on out to have me some a funnin for ma gets up and tends me to ma chores. Well, I’m a out on my 4 wheeler rig lookin for some good ole white snow mug runnin, cutting near the back of the ole forty I spots me a muddin hole. I thinks to maself, “boy, dar be some mudding overn dar on Ralphs place”, So, I jumps off ma rig and heads over for a closer peek-see. And damn’n if Ole 8 Ball just a rolling and enjoyin himself so much. I was stump’d. Thinks in ma head. ” boy, how a comin dis ole pig aint on ice?” Hmph! ” nowin dat make no darn sencin ta me. I heads on up ta Ralphs and goes to askin him how come ole 8-Ball aint a frozen.
    Well by-gawd! Dat ole pig a bin wholler’n right there in adarn ole hot mud pit. It a looked like ma wifes S.O.S. S_it on Shingles. Just a hot’n steamy. Sorta burnt bit,Can tell it’s right when it bubbles and pushes the clumps about.
    Ya’ll know what I’ma telling ya. Right? Figured So’s much.
    Thank you all for listening to my story.I think if you research the history and pick up on the clues, Without influence and an open mind, forget about theory and think more about Earths evolving, You’ll see that the earth is elaborate system of caverns, caves, oil, gas, water and FIRE. It all works together untill something fails. Then we have Natural Distaters…..

  • Whade

    I believe Steve’s got it: … read what Steve Griffith’s comment obove from February 25, 2010 at 2:04 pm says.
    :^}

  • GetOffYourHighHorse

    It’s a hoax like the bigfoot footprints or crop circles. The rocks don’t move. Someone is creating the tracks, making it look like the rocks have moved.

  • Quisco

    What about local liquefaction under and/or in front of the rock?

  • just a girl not a scientist

    So… to all these theories about ground water and such… you all do realize this is Death Valley, right? As in, like NO rain. Not literally none, but not enough to “wash away” the rocks. We are talking cm of rain, throughout a whole entire year. Not exactly enough to account for anything except maybe some of the theorized surface ice. I don’t have the answer, just pointing this out.

  • Robert

    I believe it’s a combination of water, silt, wind, gravity, and magnetic (possibly affected by lunar gravitation) effects that cause the movement. If it was caused by one singular solution it would’ve been explained long ago.

    One thing’s for sure, one shouldn’t get angry if your hypothesis isn’t automatically accepted. Only pure proof will get you that, and people have been trying to explain this phenom for decades, with very little success.

  • Drewsky

    Lil Ol’ Me, that’s not really possible because there isn’t any water in that area and even if there were, it wouldn’t leave a trail that long since the objects in question aren’t that tall.

  • Yowie9644

    Surely the likes of Google Maps or Near Maps can take regular images of the place. May not catch the smaller stones, but the big ones will be easy enough to identify.

    Wonder if freezing and thawing have anything to do with it? If ice forms at one side of the rock before the other, there’s a small but significant “lift” on that side of the rock. Would it be enough to move the rock? I have no idea. But it could explain why some rocks change paths – the ice doesn’t form on the same side each time.

  • Christian Bäro

    Can someone please call Mythbusters to the rescue?

  • Tom R

    I thought nat’l parks said take only pictures, leave only footprints. And we aren’t allowed in the name of science?!

  • GatorALLin

    This is the desert, at night it is very cold and during the day these rocks get VERY hot. Each rock only moves half a mm or less per day, but it is the massive change in temperature every day that creates the very small movement and diff. in temp and mosture of sand around rock vs. under it. (wind/gravity/magnetic forces + other have nothing to do with the movement). The darker the rock the more itcan move as it gets hotter. The shape at the front of each rock will also affect the movement some. Line up 2 rocks, paint one white and one black for heat differnce and watch the black rock move vs. the white rock…. or put a sun sheild over the top of one rock and watch it stop moving. The pattern of the sun in the sky also will slowly affect the rock movement. most rock movement is fairly straight line with some minor curving. You need a thermal camera to see how hot the rock vs. the sand temp is to really understand what is happening. You also need a microscope to see at the rock edges and under the rock. It would be easy to sent up some fun experiments to watch this…but if you are not in the desert, your experiment won’t match what is happening…

  • GatorALLin

    ——This is the desert, at night it is very cold and during the day these rocks get VERY hot. Each rock only moves half a mm or less per day, but it is the massive change in temperature every day that creates the very small movement and diff. in temp and mosture of sand around rock vs. under it. (wind/gravity/magnetic forces + other have nothing to do with the movement). The darker the rock the more it moves. The shape at the front of each rock will also affect the movement some. Line up 2 rocks, paint one white and one black for heat differnce and watch the black rock move vs. the white rock…. or put a sun sheild over the top of one rock and watch it stop moving.

  • SarahBeara

    Faith moves mountains. What are mountains made of?? ..Rock..

  • Jw kesslar

    During the rainy season a shallow lake forms at one end of the playa. You can find video on YouTube of the water in that lake quickly being driven across the surface of the playa by high winds. It also gets cold enough at night for ice to form on the surface of the ice.

    I suspect the water surrounds the rocks and turns the playa’s surface into a slick, thick mud with a reasonably firm surface that can support some weight. If you have ever tried walking on a mud flat (growing up on eastern Long Island I have) you will know that such mud can become very slick and slippery but will support a person’s weight. I have fallen more than once trying to walk on the stuff.

    At night ice forms on the surface of the shallow standing water. Winds blow the ice around. The ice hits the rocks applying force to them, and the rocks are pushed across the slick surface, leaving a trail in the mud.

    When the water goes away and the mud dries, you see the rocks have moved.

  • Genoajoe

    Occam’s Razor generalizes that the simplest explanation for a phenomenon is the most likely. This tosses out
    aliens, magnetic fields and ants. Some pictures show rock trails traveling in different directions; if gravity or wind were powering the movement, the trails would be parallel in a small area. This leaves the relevant factors of water, slippery clay and flat bottoms of the rocks plus local changes in the climate: The high playas of Death Valley experience a dramatic temperature range. If rocks move in different directions and only when the clay is wet, a reasonable hypothesis would be that the mud freezes under the rocks and lifts them; then sunshine melts the ice first on the East, South or West side, depending upon the time of sun exposure and color and geometry of the rock. The collapse of ice crystals under the rock allows the rock to subside in that direction, thus moving it by small increments. Over time the increments add up to a long trail.

    Tests of the hypothesis: 1. Do rocks ever move due North? 2. Can a smooth bottomed rock in a level, slippery, controlled environment be shown to move similarly in response to water freezing at night and melting in sunshine?

  • Al

    Why not leave several different metal sheets out there. Also, you could leave different rocks, potential magnetic and non magnetic. In this way you could see if any of them move, and then narrow down which force is acting on them.

  • Boyd Colton

    Some of you scientific minds might look into the fact that clay swells when wet and is slippery when wet. And the swelling and wet cycle of death valley playa is what moves the rocks. Swelling of wet clay. Think about it???

  • jeff

    I ve seen the rocks in death valley. It is the wind and water, but this area has mini torados blowing thru all the time. Which can drag rocks in funny ways specially when ground is wet and catches them,but can t lift them. It sometimes spins them to move. I thought about it and I am sure this is the answer- mini desert tornados.

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