English version.
In Racetrack Playa (a
dry lake) in Death Valley National Park in California some rocks move
without the intervention of men or animals.
The rocks that make
these movements can weigh as much as 300 kg (about 700lb).
The mechanism
underlying these movements has not yet been well understood, although
the phenomenon has been known and documented since the
1950s.
Previous theories for explaning the phenomenon involved: hurricanes, algae films and ice sheet.
The mechanism I propose is based on the following facts:
Previous theories for explaning the phenomenon involved: hurricanes, algae films and ice sheet.
The mechanism I propose is based on the following facts:
- in the Racetrack Playa occasionally there are small floods, in any way there are precipitation (about 33 mm / year = 1.3 in / year);
- the wind is common and can reach great speeds and intensity;
- in the valley you can experience very high temperatures. Sometimes it is so hot that you can cook an egg simply by exposing it to the sun in a frying pan.
The ingredients of hypothesis.
Step 1.
The wind strikes the rock. The air temperature rises above the boiling point of the water.
Step 2.
Hot air goes under the rock. Water under the rock becomes a "cushion" of steam. This greatly reduces the coefficient of friction between soil and rock and the wind can push the rock forward.
The trail left behind
the rock helps to gather rainwater under the rock to start a new
movement.
References:
