}

The sound of the drum in the desert

2006/09/03 Rementeria Argote, Nagore - Elhuyar Zientziaren Komunikazioa

The desert is a mysterious place, unknown. It is not a place to go alone, imagine that, in the shelter of a caravan, eleven people have been lost. The legend says that to get lost it is enough not to have a moment of caravan in sight; the spirits confuse us: they will whisper our name and we will also hear the sounds of the drum. Thanks to science, these sounds have their explanation.
After the mysterious sounds of the desert there is a collision between grains of sand, as some physicists explain.
Aitziber Lasa

During his trip to China, Marco Polo followed the Silk Road in Asia and crossed the Gobi desert. And on the desert of Lop de Gobi he wrote, among other things, the book entitled The Voyages of the Marco Polo ( Il Milione ). “During the night, when someone walks away from the caravan to sleep or for another need, while trying to meet again with the traveling companions, he hears voices calling by his name. Consequently, the passenger loses even more until it is completely lost. Many travelers have been lost and died that way. During the day the voices of strange spirits and tools like drums are also heard.”

After the mystery

Sounds and voices in the desert. It is undoubtedly a mysterious question, capable of awakening the curiosity of the human being. If you want to know the explanation of the event, the legend explains the mystery through the spirits. From the point of view of current thought, however, the explanation of legend cannot be accepted and requires rigorous scientific research. And it is that the sounds of the desert are not a legend, they are real facts.

Legend says that spirits confuse the traveler if he loses himself in the desert.
MEC

At least drum or similar sounds are quite common in some deserts. This phenomenon occurs in the deserts of residual dunes. Not all deserts are formed by remains, moreover, in many deserts appear more of a structure: dune zones, plains covered with gravel, mountains... But these mysterious sounds are only heard in areas with dunes.

As they have known so far, this sound occurs when the residual dunes fall. When the sand of a dune falls (when sand detachment occurs), the sound comes out forcefully up to 105 decibels and can reach ten kilometers.

Well, according to recent studies, these special sounds are due to the synchronization of the movement of the grains of sand. Therefore, the event is not related to the dune itself, but only to the sand. The physical explanation of desert sounds is the resonance of the grains of the residual layer that collapse and produce resonance waves that make the residual layer vibrate.

The support of the team is important to travel through the desert, hence the custom of composing caravans.
Aitziber Lasa

The researchers have worked in two places to study the behavior of sand grains: the laboratory and some dunes of Morocco. Once the study is finished, several data have been published. For example, for resonance to occur, a layer of two or three centimeters is considered sufficient, so a very high residual layer is not required, while as for speed, the grains of sand must move 0.45 meters per second or faster, and the wet sand does not produce resonance.

Thus, the mystery of the sounds of the drum in the desert is solved; the Marco Polo XIII. The explanation he received in the twentieth century is, at least, surpassed.

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