With all of the advanced technology at our fingertips today, it's somehow comforting that Mother Nature can still surprise us with her secrets. For many years, the sailing stones of Death Valley represented one of the most curious mysteries that scientists had never been able to solve…until recently, that is.
Perhaps the sailing stones kept their secret for so long because they're so hard to reach. Deep within Death Valley National Park you'll find a dry lake bed (called a playa) nestled between two mountain ranges. Racetrack Playa, as it is known, is approximately three miles long and one and a half miles wide.
To reach Racetrack Playa, you'll need a four-wheel-drive vehicle with good ground clearance and tough, off-road tires. You'll want to set aside about three and a half hours to drive the 27 miles on the washboard gravel road that leads to the playa.
Uphill all the way, you'll be dodging boulders and trying to avoid the sharp rocks that'll puncture your tires. If you do get a flat tire, you'd better know how to change it. You won't be able to call for assistance, since there's no cell phone reception in the area.
Racetrack Playa formed as a result of dramatic climate change that occurred over 10,000 years ago. This climate change resulted in the lake that existed in the valley evaporating, leaving behind light brown mud that's more than 1,000 feet thick.
Today, Racetrack Playa receives only about one to two inches of rain each year. This dry and incredibly hot environment is one of the harshest on Earth. Footprints left on the playa can last for many years before enough moisture and wind can erase them.
Erosion of the surrounding mountains causes rocks of all different sizes to fall to the surface of Racetrack Playa. For many years, visitors to Racetrack Playa have noticed that these rocks appear to have moved by themselves.
While no one had ever seen one of the rocks move, it was clear that they did indeed move. Clear tracks behind the rocks revealed that some of them had moved as much as 1,500 feet. Since there were no footprints around, these rocks — known as "sailing stones" — were somehow moving on their own.
But how is that possible? Rocks don't have feet. Have you ever seen a rock move on its own? Of course not! The sailing stones of Racetrack Playa baffled scientists. Sure, there were plenty of theories. From aliens to some sort of weird magnetic effect, none of these theories could ever be supported with any physical evidence.
Scientists who studied the rocks noticed that not all of the rocks moved. The ones that did move only moved every two or three years. Further complicating things was the fact that the stones that moved never moved at the same time or in the same direction. What's going on at Racetrack Playa?
Recently, scientists used time-lapse photography, motion-activated GPS receivers, and a great deal of patience to solve the mystery of the sailing stones once and for all. So how do the sailing stones move? It's due to a rare and unique combination of water, ice, and wind.
When the playa fills with water after it rains or snow melts from nearby mountains, thin sheets of "windowpane" floating ice can form during cold winter nights. As temperatures rise during the day, the sheets of ice start to melt and break into large, jagged panels of ice that resemble broken windows.
These panes of ice can be pushed easily across the slick, wet mud by even light breezes. As they move across the playa, they push rocks in front of them. The rocks leave trails in the mud below as they move. When the ice is gone and the playa dries out, all you can see is the rock and the evidence of how far it has moved!