In the dusky, cracked surface of a dried up lake bed in Death Valley, California, the stones move across the desert all by themselves.
On the barren Racetrack Player, the rocks, some as big as 700 pounds, leave trails in the sand, marking their inexplicable movements. Some of the tracks are nearly 600 feet long.
The 'magic' force behind these 'sailing stones' has been a mystery to scientists for nearly a century.
Now, a NASA geologist believes he has finally found the answer.
Mystery: The sailing stones of the Racetrack Playa in Death Valley have stumped scientists for nearly 100 years
Leaving their mark: No one has actually been able to record the stones physically moving, but the trails they leave in the mudflats offers proof of the path that have taken
Mythic: The strange and wonderful movement of the stones in the barren expanse of Death Valley has led some to say that the rocks are magic or are manipulated by aliens
Professor Ralph Lorenz, a planetary scientist, believes the rocks become encased in ice during the winter, then as the lake bed thaws and becomes muddy, the ice allows the rock to 'float' on the mud - making them easily blown around by strong desert winds. In an interview with Smithsonian magazine, he summarized his 2009 breakthrough this way: 'Basically, a slab of ice forms around a rock, and the liquid level changes so that the rock gets floated out of the mud.
'It’s a small floating ice sheet which happens to have a keel facing down that can dig a trail in the soft mud.'
To date, no scientist has been able to record the rock physically moving. It is believed that no one has ever seen them in motion.
Smithsonian reports that Lorenz devised his theory after a simple experiment on his kitchen counter.
He froze a small rock in just enough water that a small amount of the stone was sticking out of the ice.
The dried lake bed of the Racetrack Playa greats the perfect conditions to allow the stones to 'sail'
Theft: The Parks Service has begun investigating several incidents where stones were stolen from Death Valley because people believe they hold magical powers
Dr Ralph Lorenz's theory indicates the rocks could move with only a slight breeze, under the right conditions, because the ice causes them to float - dramatically reducing their friction
He then flipped the stone upside down and placed it in a small pool of water with sand on the bottom. The ice allowed the stone to float just enough that it still touched the sand.
Dr Lorenz found he could move the rock around simple by blowing it gently.
Previously, scientists have theorized that massive sheets of ice locked several rocks together and blew them through the desert.
However, new mathematical models calculated that winds would have to be hundreds of miles an hour to push the rocks in this way.
This stone appears to have changed direction midway through its course of sailing across the desert
Like most geological phenomena, the mystery of the 'sailing stones' comes down to wind and water
Dr Lorenz's theory indicates the rocks could move with only a slight breeze, under the right conditions, because the ice causes them to float - dramatically reducing their friction.Despite this new explanation for the movements of the 'sailing stones,' park rangers say many visitors continue to attribute mythical properties to the rocks on the Racetrack Playa.
Visitors have claimed magnetism, aliens and mysterious energy fields move the rocks. Some of the most superstitious believe that stones have magical properties.
Last month, the Los Angeles Times reported that park rangers have begun investigating the disappearance of several of the stones.
'We've had more instances of folks taking the rocks,' Death Valley spokesman Terry Baldino told the Times. 'They don't seem to understand that outside of the Racetrack, these marvelous rocks have no value.'
It's really amazing stone, and the world either!
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