People of the world know Death Valley of California for mysterious phenomena of moving rocks. These phenomena also known as rolling stones, sliding rocks, sailing rocks and moving rocks.
Here rock moves and mark a long track along a smooth valley floor without animal or human involvement. Weight of some stone is more than 300 kg that make this place weirdest because it is impossible to move rock having weight more than 300 kg without using a force. In normal life stone of such weight never change its position until we use some force to remove that from its place.
In 1972 scientist conducted a study on these rocks and recorded the stones position over a seven year period. During the seven year study only two stone out of thirty moved .They found that largest stones have weight 36 kg and cover the distance 201 meters and the smallest stone have size 6.4 cm and cover the distance 260 meters.
Tracks of moving rocks have been observed and studied but yet the origins of stone movement were not confirmed. Several hypotheses existed for sailing rocks.
The pattern of trails of sliding rocks varies in both direction and length. Rock from same origin travel parallel to time and change their way to the left, right, or even back to the route from which it originates. Length of trail also varies two similarly sized and shaped stones may travel uniformly and one of them could move ahead or stop in its track.
People believe that death valley stone having magical properties because of this many of them stolen.
Some researchers observed rock movements using GPS and reported mystery has been solved there research based on earlier concept of winds and thick ice floating rocks off the surface. According to them rocks move when large ice sheets few millimeters thick floats during sunny days.
In other study scientist say slippery bacteria cause the moment of sliding rock which produce slippery substances and live on the bottom of lagoon. Some of the stones not moved from the decade and some of them slide in different time zone in different weather condition. Sliding stones requires a rare combination of events for movement.
But people relate these phenomena with alien and magnetic field of earth or even to evil spirits. But real reason behind sailing stone still unknown.