Incredible Death Valley mystery finally solved

Before you go, we thought you'd like these...
Incredible Death Valley Mystery Finally Solved

There's a place in Death Valley National Park where a mystery that has puzzled scientists and park visitors for decades finally has been solved.

Across a dry lake in the park known as the Racetrack Playa, hundreds of rocks scattered along the ground -- many weighing up to several hundred pounds -- seem to move all on their own. They leave behind long, winding trails in the lakebed, evidence that something has been pushing or sliding them across.

Researchers have guessed at the forces moving them since the rocks were discovered nearly a century ago, but no one had seen them move until last December, when a team of scientists led by Richard Norris, a paleobiologist with the Scripps Institution of Oceanography, caught them on camera.
40 PHOTOS
Death Valley
See Gallery
Incredible Death Valley mystery finally solved
UNITED STATES - JUNE 15: Sand desert, Death Valley National Park, California, United States of America. (Photo by DeAgostini/Getty Images)
DEATH VALLEY NATIONAL PARK, CA - MAY 23: A view of Badwater Basin from Dante's View on May 23, 2014 in Death Valley California. (Photo by Ethan Miller/Getty Images)
DEATH VALLEY NATIONAL PARK, CA - MAY 23: A view of Badwater Basin from Dante's View on May 23, 2014 in Death Valley California. (Photo by Ethan Miller/Getty Images)
DEATH VALLEY NATIONAL PARK, CA - MAY 23: A view of Badwater Basin (below) from Dante's View on May 23, 2014 in Death Valley California. (Photo by Ethan Miller/Getty Images)
DEATH VALLEY NATIONAL PARK, CA - MAY 23: Tourists walk at Dante's View on May 23, 2014 in Death Valley California. (Photo by Ethan Miller/Getty Images)
DEATH VALLEY NATIONAL PARK, CA - MAY 23: A view of Badwater Basin from Dante's View on May 23, 2014 in Death Valley California. (Photo by Ethan Miller/Getty Images)
VISALIA, CA - FEBRUARY 5: A bald eagle flies along a hillside of rocks and dead grass on February 5, 2014 near Visalia, California. Now in its third straight year of unprecedented drought, California is experiencing its driest year on record, dating back 119 years and possible the worst in the past 500 years. Grasslands that support cattle have dried up, forcing ranchers to feed them expensive supplemental hay to keep them from starving or to sell at least some of their herds, and farmers are struggling with diminishing crop water and what to plant or whether to tear out permanent crops which use water year-round such, as almond trees. About 17 rural communities could run out of drinking water within several weeks and politicians are are pushing to undo laws that protect several endangered species. (Photo by David McNew/Getty Images)
VISALIA, CA - FEBRUARY 5: A bald eagle perches in an oak tree on hills of pastureland that has turned of dirt and dead grass on February 5, 2014 near Visalia, California. Now in its third straight year of unprecedented drought, California is experiencing its driest year on record, dating back 119 years and possible the worst in the past 500 years. Grasslands that support cattle have dried up, forcing ranchers to feed them expensive supplemental hay to keep them from starving or to sell at least some of their herds, and farmers are struggling with diminishing crop water and what to plant or whether to tear out permanent crops which use water year-round such, as almond trees. About 17 rural communities could run out of drinking water within several weeks and politicians are are pushing to undo laws that protect several endangered species. (Photo by David McNew/Getty Images)
A dead tree is seen against a barren landscape in the Tejon Pass between the San Joaquin Valley to the north and Los Angeles to the south, in Lebec, California, January 22, 2014. Amid California's driest year on record, Governor Jerry Brown declared a drought emergency in the state. The lack of rain is threatening crops in the San Joaquin Valley. AFP PHOTO / ROBYN BECK (Photo credit should read ROBYN BECK/AFP/Getty Images)
DEATH VALLEY NATIONAL PARK, CA JULY 16: Ray Sanchez (L) of Sacramento, California runs along highway 136 north of Lake Owens as he approaches the town of Lone Pine during the AdventurCORPS Badwater 135 ultra-marathon race on July 16, 2013 outside of Death Valley National Park, California. Billed as the toughest footrace in the world, the 36th annual Badwater 135 starts at Badwater Basin in Death Valley, 280 feet below sea level, where athletes begin a 135-mile non-stop run over three mountain ranges in extreme mid-summer desert heat to finish at 8,350-foot near Mount Whitney for a total cumulative vertical ascent of 13,000 feet. July 10 marked the 100-year anniversary of the all-time hottest world record temperature of 134 degrees, set in Death Valley where the average high in July is 116. A total of 96 competitors from 22 nations are attempting the run which equals about five back-to-back marathons. Previous winners have completed all 135 miles in slightly less than 24 hours. (Photo by David McNew/Getty Images)
DEATH VALLEY NATIONAL PARK, CA JULY 16: Iris Cooper-Imhof (R) of Canada walks toward Mount Whitney (L) during the ascent of Whitney Portal Road to the finish of the AdventurCORPS Badwater 135 ultra-marathon race on July 16, 2013 outside of Death Valley National Park, California. Billed as the toughest footrace in the world, the 36th annual Badwater 135 starts at Badwater Basin in Death Valley, 280 feet below sea level, where athletes begin a 135-mile non-stop run over three mountain ranges in extreme mid-summer desert heat to finish at 8,350-foot near Mount Whitney for a total cumulative vertical ascent of 13,000 feet. July 10 marked the 100-year anniversary of the all-time hottest world record temperature of 134 degrees, set in Death Valley where the average high in July is 116. A total of 96 competitors from 22 nations are attempting the run which equals about five back-to-back marathons. Previous winners have completed all 135 miles in slightly less than 24 hours. (Photo by David McNew/Getty Images)
DEATH VALLEY NATIONAL PARK, CA JULY 15: Runners pass through Death Valley during the AdventurCORPS Badwater 135 ultra-marathon race on July 15, 2013 in Death Valley National Park, California. Billed as the toughest footrace in the world, the 36th annual Badwater 135 starts at Badwater Basin in Death Valley, 280 feet below sea level, where athletes begin a 135-mile non-stop run over three mountain ranges in extreme mid-summer desert heat to finish at 8,350-foot near Mount Whitney for a total cumulative vertical ascent of 13,000 feet. July 10 marked the 100-year anniversary of the all-time hottest world record temperature of 134 degrees, set in Death Valley where the average high in July is 116. A total of 96 competitors from 22 nations are attempting the run which equals about five back-to-back marathons. Previous winners have completed all 135 miles in slightly less than 24 hours. (Photo by David McNew/Getty Images)
DEATH VALLEY NATIONAL PARK, CA - JUNE 30: Heat waves distort the appearance of a car when the temperature reaches 119 degrees and rising as a heat wave spreads across the American West on June 30, 2013 in Death Valley National Park, California. Weather forecasters predict that high temperatures could reach 130 degrees in Death Valley today and tomorrow, breaking the hottest-ever temperature for June of 128 degrees, set on June 29, 1994. It is also just four degrees shy of breaking the all-time world record of 134 degrees which occurred here 100 years ago on July 10, 2013. Since then, the 130-degree mark has never been repeated and the 129-degree mark has occurred on only four occasions. Formerly, it was thought that the world's highest temperature occurred in El Azizia, Libya in 1922 but an international team of climate experts from the World Meteorological Organization (WMO) declared that reading invalid because of the combination of poor weather instrumentation which was operated by an inexperienced record-keeper located in a bad spot for accurate readings. (Photo by David McNew/Getty Images)
California and Nevada, Death Valley National Park, Sand Dunes in Mesquite Flat, and Cottonwood Mountains in the background. (Photo by: Universal Images Group via Getty Images)
California and Nevada, Death Valley National Park, Badwater Basin, Mesquite and the Black Mountains of the Amaragosa Range from Mormon Point. (Photo by: Universal Images Group via Getty Images)
California and Nevada, Death Valley National Park, Sand Dunes in Mesquite Flat, and Cottonwood Mountains in the background. (Photo by: Universal Images Group via Getty Images)
Death Valley. (Photo by: Education Images/UIG via Getty Images)
Death Valley. (Photo by: Education Images/UIG via Getty Images)
DEATH VALLEY, CA - July 11: Runners take off down the road at the start of the Badwater Ultramarathon in Death Valley, CA, on July 11, 2011. Participants run 135 miles non-stop from Death Valley to Mt. Whitney, CA. The start line is at Badwater, Death Valley, which marks the lowest elevation in the Western Hemisphere at 280 feet below sea level. The race finishes at the Mt. Whitney Portals at nearly 8,300 feet. (Photo by Toni L. Sandys/Washington Post)
Prickly Poppy, Near Death Valley, California. (Photo by Education Images/UIG via Getty Images)
This 2013 photo provided by Xanterra Parks & Resorts shows a wavy rockscape in sun and shadow in Death Valley National Park in California. The park is one of the hottest places on earth but temperatures are less extreme in the spring than summer. (AP Photo/Xanterra Parks & Resorts)
A divot left by an off-road truck that went out of control running into a crowd of spectators at the California 200 Saturday night is shown Sunday, Aug. 15, 2010 in Lucerne Valley, Calif. The truck pinned bodies beneath it and sending others flying into a chaotic cloud of dust in a crash that killed eight people, injuring 12 authorities and witnesses said. (AP Photo/Alex Gallardo)
In this April 11,2010 photo showing tourist walking along a ridge at Death Valley National Park, Calif. California's Death Valley has racked up another extreme accolade, it's now deemed the world's hottest place. Long known as the lowest, driest and hottest spot in the United States, Death Valley this week was named as the hottest place on the globe by the World Meteorological Organization. (AP Photo/Brian Melley)
** ADVANCE WEEKEND EDITIONS DEC 16-17 ** Hikes make their way up Surprise Canyon towards Panamint City, an old mining camp at the head of this canyon near Ballarat, Calif., Dec. 10, 2006. This canyon, just miles from arid Death Valley, has inspired a passionate legal battle between two perennial foes: off-road drivers and environmentalists. (AP Photo/Chris Carlson)
A mesquite tree stands just west of Furnace Creek Ranch in Death Valley National Monument March 12, 1999. The Tibisha Shoshone tribe are considering harvesting mesquite when the land is returned to them under a recently reached agreement between the U.S. Park Service and the tribe. (AP Photo/Laura Rauch)
Tourists watch a sunset view of the mountains, looking west, from Zabriskie Point, Aug. 8, 1998, in Death Valley, Calif. Tourists from all over the globe come to experience Death Valley, which in summer is often the hottest place in the country. (AP Photo/Mark J. Terrill)
Cactus and shifting sands ? a new picture of Death Valley, whose arid sweep has claimed the lives of many a pioneer, shown Dec. 17, 1932. In the distance are the Funeral Mountains. Aside from an occasional tourist and prospector, there are few inhabitants in this region. (AP Photo)
Walter Scott “Death Valley Scotty,” who shopped all over the state of California for five weeks and spent $4,500 for 15 mules, is with Barnum, his saddle mule, and two of his pack animals in Los Angeles on July 15, 1936. The other twelve mules are scattered throughout the state and will not be assembled until Scotty leaves for the desert. (AP Photo/Ira W. Guldner)
“It’s the finest mule in the world,” said the famous Monte Christ of Death Valley, Walter Scott, as he wound up his five weeks shopping tour through California in Los Angeles on July 10, 1936, for a string of 15 pack mules, costing $4500, including pack outfits. This big bay mule weighs 1250 pounds and is 15.2 hands high. (AP Photo/Ira W. Guldner)
of
SEE ALL
BACK TO SLIDE
SHOW CAPTION +
HIDE CAPTION

In a study published Aug. 27 in the online scientific journal PLOS ONE, Norris reports on his team's two-year-long effort to photograph and track the movement of the stones, and the amazing luck they had in actually seeing them move.

"Science sometimes has an element of luck," Norris said in a news release. "We expected to wait five or ten years without anything moving, but only two years into the project, we just happened to be there at the right time to see it happen in person."

Norris and his team began their experiment in the winter of 2011, when they devised a plan to monitor the rocks' movement with a high-resolution weather station that could measure wind gusts in very small time frames. They also fitted 15 rocks -- which they brought from outside their park, as National Park Service officials wouldn't allow them to move any of the rocks already there -- with GPS devices that tracked their motion.

Next, they waited for something to happen, what study co-author Ralph Lorenz of the Applied Physics Laboratory at Johns Hopkins University said he thought would be "the most boring experiment ever."

When the team visited Racetrack Playa in December 2013, they found it covered in a pond of water about three inches deep. And then they noticed something interesting: the rocks began moving.

Here's how the Scripps Institution of Oceanography described it in their news release:

"Their observations show that moving the rocks requires a rare combination of events. First, the playa fills with water, which must be deep enough to form floating ice during cold winter nights but shallow enough to expose the rocks.

"As nighttime temperatures plummet, the pond freezes to form thin sheets of "windowpane" ice, which must be thin enough to move freely but thick enough to maintain strength. On sunny days, the ice begins to melt and break up into large floating panels, which light winds drive across the playa, pushing rocks in front of them and leaving trails in the soft mud below the surface.

On Dec. 21, Norris and his study co-author Jim Norris said they heard "popping and cracking sounds coming from all over the frozen pond surface," according to Scripps, adding: "I said to Jim, 'This is it!'

Thanks to being able to witness the rocks' movement in real time, it became clear why no one had reported seeing them move in the past. The rocks moved only a few inches every second, a speed that would be virtually impossible to notice at a distance.

"It's possible that tourists have actually seen this happening without realizing it," Jim Norris said in an interview with Scripps.

More from AOL
A flavor out of favor: Dog meat fades in S. Korea
John Lennon's killer sorry for being 'an idiot'
Japanese lawmaker, martial artists in North Korea
Read Full Story

People are Reading