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"Sailing Stones" (Racetrack Playa In Death Valley, Etc.)

A slow burner, this one;

Back in 2009...

rynner2 said:
Another article, but nothing really new, it seems:

Real-life rolling stones creep across Death Valley in California

Scientists believe the pebbly phenomenon is caused by a melting-pot of specific weather conditions.
Studies suggest a combination of 90mph winds, ice formations at night and thin layers of wet clay on the surface of the desert all combine to push them along.

http://www.telegraph.co.uk/earth/earthn ... fornia.htm l
In 2010, Mytho wrote...
I'm a little surprised that nobody has set up a webcam or time-lapse camera. That would help to shed light on the mystery.
Now someone has done just that:
United States: 'Sailing rocks' mystery finally solved
By News from Elsewhere...
...media reports from around the world, found by BBC Monitoring

Scientists have finally solved the mystery of how rocks can move across the flat ground of a dry lake bed in Death Valley, California.

Visitors have long been puzzled by the sight of boulder tracks criss-crossing a dusty bowl known as the Racetrack Playa in Death Valley National Park. But two researchers now say the rocks - which can sometimes be heavy and large - are propelled along by thin, clear sheets of ice on breezy, sunny days. They call it "ice shove". "I'm amazed by the irony of it all," paleobiologist James Norris tells the LA Times. "In a place where rainfall averages two inches a year, rocks are being shoved around by mechanisms typically seen in arctic climes."

The findings are based on a lucky accident by James Norris and his cousin Richard Norris - while they were studying the sliding rock phenomenon. They actually witnessed the boulders moving in December when they went to check their time-lapse cameras in the valley. "There was a pop-pop-crackle all over the place in front of us and I said to my cousin, 'This is it'," Richard Norris says in the science journal Nature. They watched some 60 rocks sail slowly by, leaving the well-known snaking trails in the ground. "A baby can get going a lot faster than your average rock," Norris notes. The rocks also don't slide around very often - scientists estimate only a few minutes out of a million - which is why the event has not been noticed before.

http://www.bbc.co.uk/news/blogs-news-fr ... e-28989520
So, move along now, nothing to see here... ;)

(Until another couple of years have passed, when somebody else will anounce the problem is finally solved! :roll: )
 
Source: https://motherboard.vice.com/en_us/...in-the-desert-stumped-scientists-for-70-years

Death Valley’s ‘sailing stones’ are able to move thanks to unique environmental conditions.

Have you ever seen a rock move? I mean move independently—not, like, roll after someone kicked it or knocked it over—just sliding across a flat surface of its own accord. With the exception of certain psychedelic experiences, I'm going to guess you haven't. But these rocks exist, and they stumped scientists for decades.

The Racetrack Playa is a wide, flat, desert basin in the middle of Death Valley National Park. It's surrounded by tall, rocky hills and, hundreds of years ago, was filled with water, but these days it's just a dried up lakebed. It's one of the hottest, driest, and lowest places in North America, and it's home to the "sailing stones:" rocks that move along the playa on their own. It took until 2014 for scientists to conclusively uncover how the stones get from one place to another: an unusual, and unique combination of ice, wind, and sun.

It's rare to see the stones in motion, but there's a clear sign that they've been on the move. Behind the rocks are long, sometimes winding trails in the dirt. Scientists have used GPS units to track to stones' movements, and have proven that they're mobile. They were first publicly documented in the early 1900s, but for decades, nobody could explain how they moved, according to Richard Norris, an oceanographer at University of California San Diego, and one of the researchers who finally solved the mystery of the rocks.

1493670126736-Death-Valley-Recetrack.jpeg

Image: Wikipedia

"The first scientific study was done 1948 and then there was a succession of scientific papers," Norris said. "Every ten years or so somebody published a new paper on the Racetrack, but nobody is basing their scientific career on this kind of work. It's just a really fun sort of mystery."

Norris became aware of the stones when he was just a kid. His uncle, a geomorphologist at UC San Diego, would take class trips out to the playa, and Norris and his cousin would tag along. As adults, and both scientists themselves, Norris and his cousin decided they ought to take a stab at solving how the rocks moved, so they designed an experiment.

Previous research had produced hypotheses about how the rocks moved. Some thought it was exceptionally heavy winds, others believed ice formed around the rocks and caused them to be buoyant. There were also some less scientific theories, such as acoustic levitation—the belief that sound can cause heavy objects to levitate.

To figure it all out, Norris and his cousin attached specially-designed GPS units to the back of rocks they had brought into Death Valley (the National Parks Service wouldn't let them mess with the rocks that were already there). They also installed a weather station, and then...they waited.

It took two years, but finally, the rocks moved. Norris and his cousin, completely by chance, actually got to witness them in action. The researchers discussed their findings in a paper published in PLOS One. They found that when enough rain fell on the playa to pool, and the temperature dropped, the water would freeze into huge, thin sheets of ice around the rocks—which tumble onto the playa from a nearby hillside. As the morning sun began to melt the ice, if a gentle breeze blew, it could move the ice, which dragged the rocks along with it.

"The ice is like the thickness of a window pane," Norris told me. "And although it's very thin, it's a huge, huge sheet of ice. It's sort of being moved sort of inextricably by these breezes and it can shove around really big things—and a lot of rock."

The results shocked Norris and many other scientists, but it's a phenomenon that's since explained similar moving rocks around the globe. Though it wasn't the paranormal explanation that so many people had hoped for, the truth was even more tantalizing.

"Science is delightful," Norris said.
 
Thanks for this! I wish they'd filmed it - what a thing to see.
 
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Thanks for this! I wish they'd filmed it - what a thing to see.
I'm sure this topic came up on the MB before. I tried a quick search, but couldn't find anything... I'll try again when I have more time.
 
This recently presented paper provides a number of interesting points:

- Mention of "sailing stones" known from sites other than Racetrack Playa;
- A summary of the two methods by which sailing stones are believed to move;
- A particular case involving a fossil that seems to exhibit a sailing stone track; and
- The possibly catastrophic climatic event(s) that triggered the Triassic-Jurassic extinction event, for which this fossil sailing stone track provides evidence.
Fossil Find Shows The Enigmatic 'Sailing Stones' Existed Even 200 Million Years Ago

In the Death Valley desert in California, the dry lake of Racetrack Playa is renowned for being home to a wonderful peculiarity. Here, large and heavy rocks known as 'sailing stones' regularly cruise across the ground, leaving long tracks behind them.

Such sailing stone tracks (or at least one like them) have now turned up in an unexpected place: a fossil dating back 200 million years, and prized for its exceptionally well-preserved dinosaur footprints.

The fossil, which clearly shows the shape of the foot and even skin texture of a prosauropod - an early sauropod - has been on display since 1896. No one had thought anything of the long, smeared track next to the prints, until palaeontologist Paul Olsen of Columbia University copped an eyeful in 2017.

Now, he and colleagues have presented their findings at the 2019 Fall Meeting of the American Geophysical Union. They argue that the track we see on this fossil, right there - it was left by an ancient sailing stone. ...

How did the rock slide through the dinosaur prints? According to Olsen and colleagues, their discovery could be evidence of briefly freezing temperatures in the tropics during the Early Jurassic 200 million years ago, when the dinosaur world expanded and mammals started to evolve and diversify at a furious rate. ...

The sailing stone-like track in the ancient fossil slab looks a heck of a lot like the sailing stone tracks on the Racetrack Playa. It even has striations seen in some modern sailing stone tracks, created by uneven textures on the stone as it goes through.

Thus, we get back to the team's hypothesis about the sudden freezing in the tropics, an idea that actually provides a bit of a problem.

You see, the fossil was excavated from Portland, Connecticut - a region that, 200 million years ago, would have been more equatorial, sitting at around 18 degrees latitude, with low elevation. Most of the plants and animals in the region at the time were not suited to frosty conditions. ...
FULL STORY: https://www.sciencealert.com/there-were-sailing-stones-scudding-across-the-mud-200-million-years-ago

ABSTRACT & SUMMARY OF PRESENTED PAPER:
https://agu.confex.com/agu/fm19/meetingapp.cgi/Paper/580376
 
The following video was posted on Youtube the 1/4/22 (yes I know..."April Fools Day)

99 Years Later... We Solved It The Moving Rocks.
It's interesting, but I don't think that this video has all the answers though.

1) Not all rocks seem to travel in the same direction (at the same time).
2) Where are the tracks of the smaller rocks?.
 
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1) Not all rocks seem to travel in the same direction (at the same time).
2) Where are the tracks of the smaller rocks?.
1. As someone who's seen dust-devils, tornadoes and the like, wind currents do weird things in general.

2. I would guess that they're not massive enough to leave tracks.
 
1. As someone who's seen dust-devils, tornadoes and the like, wind currents do weird things in general.

2. I would guess that they're not massive enough to leave tracks.

1) Oh, I agree about wind currents, especially living a UK suburan cul-de sac. I have seen at least 3 small "dust devils" in small space of maybe 24? ft square.
1a) IIRC The UK has more recorded Tornados than the US per year.
2) Possibly, but there again, lighter the rock, the further that rock would travel?
 
2) Possibly, but there again, lighter the rock, the further that rock would travel?
I might be misunderstanding this, but what I was getting at was if it was light enough, it could travel all over the place and yet not leave a trail.
 
I might be misunderstanding this, but what I was getting at was if it was light enough, it could travel all over the place and yet not leave a trail.

In the video, it does show that some small rocks have moved though:- 1:08 to 1:15.
 
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