Ahhh this is one that captured my imagination quite a while back. Now this particular phenomenon takes place in a basin called Racetrack Playa, Death Valley National Park in California. The basin is actually a dried up lake about 3 miles long and is surrounded by mountains that help channel the winds into the basin at high speeds. Now what is it about these rocks you may ask...well, i'll tell you....
Satellite image of the basin
The rocks are located in the southern end of the basin, with these chunks of dolomite weighing anywhere from a measly few pounds up to a hefty 700 pounds. They sit pretty in their dried up lakebed under the scorching California sun and do what rocks generally do, just sit there. However, the reason why they're called the Racing Rocks is because they move. Yes you read that right, they move...and on their own to boot. You see, the basin floor is basically dried mud and something moving along the ground would leave a trail in the baked mud. So as the rocks move, they leave long, clear furrows that can be followed. Their tracks vary in length, going every which way from zig-zags to loops; some double back on themselves. Some travel only a few feet; others go for hundreds of yards, yet they can be right next to each other, and right next to some that don't move at all. The choice of rocks and direction of movement seem totally random and most probably is. Even more spinetingling is the fact that no one has ever actually seen the rocks moving. The final location of the rocks and the trails they leave are all that viewers have to witness. However, as with most phenomena, there are a number of theories to explain these mysterious movements.
In a hurry to go nowhere
Theory 1 : That hoaxers drive out there in the scorching sun, drag some rocks around to create trails, somehow erase their own tracks, avoid the detection of the National Park rangers, and hustle outta there,chuckling all the while at their magnificent plot to...urm...i'm not sure what's the point...
Theory 2 : Under specific weather conditions (rain, fog, dew, etc), the dried mud becomes a thin layer of slippery soil that allows the stones to glide around, pushed by the wind. However, this doesn't take into account the fact that the furrows are pretty deep and you would need an incredible amount of wind force to get the rocks to move that way. In addition, if the wind DID blow at that kind of velocity, why is it that some rocks move and some don't? Size doesn't seem to be much of factor and rocks that do move don't move in the same pattern.
Theory 3 : During especially wet winters several inches of water collect on the playa surface, turning it briefly into a lake. On cold nights it's surmised that thin sheets of ice form, locking in rocks. When the strong winds blow through the valley and hit the ice sheets at an angle, the wind pushes with enough force to move the ice and the rocks embedded in it along the slippery surface. This one doesn't take into account the fact that the rocks move irrespective of season and still exbihits movement in the driest seasons of the year.
Theory 4 : Squirrels with super-rodent strength that push the rocks together for shelter in difficult winters...ok,moving on...
Paul Messina from the Department of Geology in San Jose University did what i would do and tracked the movements of 162 rocks using Differential Geographical Positioning System (DGPS) which is accurate up to 30 centimeters or so. What he found was that the trail patterns showed a general trend in rock movement consistent with the direction of the prevailing winds. However, there is a high degree of variation in trail character. A rock's distance travelled and the degree to which it follows a straight line is more significantly influenced by where it was before it moved rather than any physical attributes of the stone. This is taken to mean that the winds are channeled more strongly in certain 'corridors' hence pushing the rocks located there further. While the report sounds convincing and very confident, the thought occured to me that it doesn't explain how come some of the rocks double back. They make a nice smooth u-turn and head back home. What's more is that some rocks can be seen to be moving past each other in opposite directions and there may even be a third rock sitting there that hasn't moved at all.
Imagine the wind blowing a rock around like that
The explanation for this mystery could be a combination of many mundane factors but i'm hoping that the true explanation is so mind-boggling that we would have to sit down and totally reevaluate our belief systems. Maybe something like dormant alien energy sitting deep beneath the soil that infuses the dolomite chunks with semi-sentience, enabling them to struggle towards the horizon and as consciousness wanes with every inch away from the energy, they finally stop dead in their herculean effort to inch their rocky bodies across the baked landscape, leaving naught but a trail of dust to mark their passing...a fitting silent eulogy for a life that almost was...
