A very old and popular mysterious topic on the Internet is the Crawling Stones of Death Valley. Well, you remember that this is a geological phenomenon discovered on the dried up Lake Racetrack Playa in Death Valley in the USA. The stones slowly move along the clayey bottom of the lake, as evidenced by the long footprints that remain behind them. The stones move independently without the help of living beings, but no one has ever seen or recorded the movement on camera. The stones come into motion only once every two or three years, and most of the tracks last for 3-4 years.
Until the beginning of the 20th century, the phenomenon was explained by supernatural forces, then during the formation of electromagnetism, the assumption arose about the effect of magnetic fields, which, in general, did not explain anything. Most of the hypotheses agreed that the wind at a wet lake bottom explains the phenomenon at least in part.
And in 2014, a work was published in the Public Scientific Library, the authors of which describe the mechanism of the movement of stones.
The fact is that not everyone knows that these stones are located on a dry lake, which is sometimes filled with water.
Therefore, the scientists placed several of their stones weighing 5-15 kg at the bottom of the lake, equipping them with navigation sensors and surrounding them with cameras. The reason for the movement was large (tens of meters), but thin (3-6 mm) areas of ice formed after freezing in the previous frosty nights. This floating ice, carried away by the wind and under-ice currents, moved stones at a speed of 2-5 m / min.
Full study in English -
Something like that I do not mind "freshness" in this scientific article.
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In fairness, it should be noted that back in 1955, geologist George Stanley from the University of Michigan published an article in which he and his colleague proposed a theory according to which, during the seasonal flooding of a dry lake, an ice crust forms on the water, which promotes the movement of stones.
In May 1972, Robert Sharp (California Institute of Technology) and Dwight Carey (University of California at Los Angeles) began a stone movement monitoring program. Thirty stones with relatively fresh footprints were marked and their location was marked with pegs. For 7 years, during which the position of the stones was recorded, scientists have created a model according to which, during the rainy season, water accumulates in the southern part of the lake, which is spread by the wind along the bottom of the dried lake, wetting its surface. As a result, the hard clay soil is very wet and the coefficient of friction is sharply reduced, which allows the wind to move even one of the largest stones (it was named Karen), which weighed about 350 kilograms, from its place.
Hypotheses of ice movement were also tested. Wind-spread water can be covered with ice at night, and stones located in the path of the water will be frozen into the ice layer. The ice around the rock could increase the cross-section of interaction with the wind and help move rocks along water streams. As an experiment, a corral with a diameter of 1.7 m was created around a stone 7.5 cm wide and weighing 0.5 kg.
The distance between the supports of the fence varied from 64 to 76 cm. If a layer of ice formed around the stones, then during movement it could catch on the support of the fence and slow down the movement or change the trajectory, which would be reflected on the track from the stone. However, no such effects were observed - in the first winter the stone passed near the fence support, moving 8.5 m beyond the fenced area in the direction of the northwest. The next time, 2 heavier stones were placed inside the corral - one of them moved in the same direction as the first five years later, but its companion did not budge during the research period. This fact indicated that if the ice crust has an influence on the movement of stones, then it must be small. Here's a contradiction with the latest 2014 survey!
Ten of the marked stones moved during the first winter of exploration, with Stone A (called Mary Ann) crawling 64.5 m. It was noted that many stones also moved in the next two winters, and in summer and other winters, the stones remained in place. At the end of the study (after 7 years), only two of the 30 observed stones did not change their location. The smallest of the stones (Nancy) was 6.5 cm in diameter, and this stone moved to the maximum total distance of 262 m and to the maximum distance in one winter - 201 m. The most massive stone, the movement of which was recorded, weighed 36 kg.
In 1993, Paula Messina (California State University at San Jose) defended her thesis on moving stones, which showed that, in general, stones did not move in parallel. According to the researcher, this confirms that ice does not promote movement in any way. After studying the changes in the coordinates of 162 stones (which were carried out using GPS), it was determined that the movement of the boulders was not affected by their size or their shape. It turned out that the nature of the movement is largely determined by the position of the boulder on Racetrack Playa. According to the created model, the wind over the lake behaves in a very complex way, even forming a vortex in the center of the lake.
In 1995, a group led by Professor John Reid noted the high similarity between the tracks of the winter of 1992-93 and those of the late 1980s. It was shown that at least some of the stones moved with streams of ice-covered water, and the width of the ice crust was about 800 m, as evidenced by characteristic tracks scratched by a thin layer of ice. It was also determined that the boundary layer, in which the wind slows down due to contact with the ground, on such surfaces can be only 5 cm, which means the possibility of exposure to winds (the speed of which reaches 145 km / h in winter) even on very low stones.
So there are probably several reasons why stones can move, and they can act simultaneously. But this is definitely not magic:-)