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Astronomy Picture of the Day -- A Sailing Stone in Death Valley
NASA ^ | February 22, 2012 | (see photo credit)

Posted on 02/21/2012 9:54:30 PM PST by SunkenCiv

Explanation: How did this big rock end up on this strange terrain? One of the more unusual places here on Earth occurs inside Death Valley, California, USA. There a dried lakebed named Racetrack Playa exists that is almost perfectly flat, with the odd exception of some very large stones, one of which is pictured above. Now the flatness and texture of large playa like Racetrack are fascinating but not scientifically puzzling -- they are caused by mud flowing, drying, and cracking after a heavy rain. Only recently, however, has a viable scientific hypothesis been given to explain how 300-kilogram sailing stones ended up near the middle of such a large flat surface. Unfortunately, as frequently happens in science, a seemingly surreal problem ends up having a relatively mundane solution. It turns out that high winds after a rain can push even heavy rocks across a temporarily slick lakebed.

February 22, 2012

(Excerpt) Read more at 129.164.179.22 ...


TOPICS: Astronomy; Astronomy Picture of the Day; Science
KEYWORDS: apod; astronomy; deathvalley; science
[Credit: Nathan Alexander, Wikipedia]

1 posted on 02/21/2012 9:54:40 PM PST by SunkenCiv
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To: brytlea; cripplecreek; decimon; bigheadfred; KoRn; Grammy; married21; steelyourfaith; Mmogamer; ...

I think there's been a topic or two about these before, but here ya go!

2 posted on 02/21/2012 9:55:45 PM PST by SunkenCiv (FReep this FReepathon!)
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To: SunkenCiv

You rock!


3 posted on 02/21/2012 9:56:57 PM PST by null and void (Day 1127 of America's ObamaVacation from reality [Heroes aren't made, Frank, they're cornered...])
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To: SunkenCiv

And what does this have to do with Astronomy? I enjoy the “Astronomy Picture of the Day” greatly, however ...


4 posted on 02/21/2012 10:01:16 PM PST by doc1019 (Romney will never get my vote!)
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To: SunkenCiv

Did you know that Death Valley is sinking? The valley has been sinking about 1/2 in per year.In relation to the valley, the Black Mountains under you are movng to your left as well as rising. The eroding mountains fill the valley at about the same rate as it sinks.


5 posted on 02/21/2012 10:01:32 PM PST by U-238
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To: SunkenCiv
Unfortunately, as frequently happens in science, a seemingly surreal problem ends up having a relatively mundane solution. It turns out that high winds after a rain can push even heavy rocks across a temporarily slick lakebed.

Don't have an answer, but I'm not buying that wind pushed a 660 pound rock.

6 posted on 02/21/2012 10:05:44 PM PST by umgud (No Rats, No Rino's)
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To: doc1019

Death Valley is mentioned in several prominent Astronomy Books. In fact NASA tested the Viking probes to Mars here.


7 posted on 02/21/2012 10:05:44 PM PST by U-238
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To: U-238

Still, what does this have to do with our daily Astronomy picture of the day. This should be presented in “Our Geology Picture of The Day”, not here.


8 posted on 02/21/2012 10:11:23 PM PST by doc1019 (Romney will never get my vote!)
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To: doc1019

NASA has also Death Valley on their Earth Observatory site,too


9 posted on 02/21/2012 10:20:34 PM PST by U-238
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Death Valley has similar geology to the Red Planet


10 posted on 02/21/2012 10:24:45 PM PST by U-238
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To: U-238

So, in my repartee of saved Astronomical pictures, I should consider this one as just another “astronomical phenomenon”?


11 posted on 02/21/2012 10:27:33 PM PST by doc1019 (Romney will never get my vote!)
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To: SunkenCiv

http://www.youtube.com/watch?v=u1hoiHvOeGc


12 posted on 02/21/2012 10:29:01 PM PST by smokingfrog ( sleep with one eye open (<o> ---)
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To: doc1019

Death Valley is a important site on the planet and in Solar System.


13 posted on 02/21/2012 10:40:44 PM PST by U-238
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To: umgud

You do realize that it is “wind” that lifts a Boing 747-400 weighing 870,000 lbs (max takeoff wt) up into the air.

SO on an extremely “slick” (very low coefficient of friction) muddy surface, a very strong desert wind - which can easily exceed 100 mph - can generate enough horizontal force to break the rock free, and then, once it is moving, slide it these long distances.

Visualize a weatherman showing off in a hurricane, and being blown away down the road.

Weatherman - rock - basically the same thing... :-)

:-) to any weathermen, don’t be offended.


14 posted on 02/21/2012 11:06:56 PM PST by muffaletaman (ABOAR)
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To: muffaletaman

Not sold. BTW, a 747 has wings.


15 posted on 02/21/2012 11:11:20 PM PST by umgud (No Rats, No Rino's)
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To: umgud

Morelocks. That’s my guess.


16 posted on 02/21/2012 11:32:12 PM PST by Ken H (Austerity is the irresistible force. Entitlements are the immovable object.)
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To: umgud

“Don’t have an answer, but I’m not buying that wind pushed a 660 pound rock.”
Think of a beer being slid from on end of a bar to the other.


17 posted on 02/22/2012 12:21:29 AM PST by BigCinBigD
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To: SunkenCiv

I’ve read about this for years. I first came across it in a strange phenomenon book from the 60s or early 70s and this was given as one particularly plausible explanation. Its really neat, but nothing new regarding science.


18 posted on 02/22/2012 12:22:06 AM PST by lefty-lie-spy (Stay metal. For the Horde \m/("_")\m/ - via iPhone from Tokyo.)
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To: lefty-lie-spy
but nothing new regarding science.

You obviously do not understand Science.

What makes this different than all those decades old speculations is that this is prefaced by, "Scientist says...".

19 posted on 02/22/2012 12:35:37 AM PST by ApplegateRanch (If any of their "Alternatives" actually works, the Greenies will proceed to kill it.)
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To: umgud
Not sold. BTW, a 747 has wings.

But a truck or a van doesn't, and the wind can push on those hard enough to tip then over or push them off the road.

20 posted on 02/22/2012 12:55:13 AM PST by El Gato ("The second amendment is the reset button of the US constitution"-Doug McKay)
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To: El Gato

Sounds like a job for Myth Busters. Although the photograph in question with the trail in the dirt running up to the rock, and no vehicle tracks, footprints, etc. would also seem to support the theory. Or maybe leave a cheap webcam triggered by motion on a tripod (VERY WELL ANCHORED!) by the rock and wait for the next windstorm might confirm it.


21 posted on 02/22/2012 1:04:04 AM PST by 21twelve
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To: muffaletaman; umgud
You do realize that it is “wind” that lifts a Boing 747-400 weighing 870,000 lbs (max takeoff wt) up into the air.

Actually wind doesn't lift the airplane, vacuum does. The air going over the top of the wing moves slower than the air going under it and creates a vacuum, the air rushing to fill the vacuum lifts the plane. This is a different, and quite a lot stronger, force than simple wind. There is no vacuum created in front of the large rocks that move, at least I don't think so, unless the rocks have an airfoil shape to them.

22 posted on 02/22/2012 2:47:08 AM PST by calex59
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To: SunkenCiv

You mean it’s NOT Giant Aliens playing checkers?

I am SO disappointed! :-)


23 posted on 02/22/2012 4:07:17 AM PST by left that other site
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To: SunkenCiv
It turns out that high winds after a rain can push even heavy rocks across a temporarily slick lakebed.

Once they're moving, but what gets them unstuck to begin with?
24 posted on 02/22/2012 4:11:53 AM PST by aruanan
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To: SunkenCiv
From the Conclusion in the dissertation (emphasis added):
Despite the extensive work conducted most notably by Kirk (1952), Stanley (1955), Sharp and Carey (1976) and by Reid et al. (1995) the causative conditions promoting the sliding rocks’ motions remain unclear.

At the outset this project was conceived and designed in hopes of revealing predictable order in the sliding rock trails. The patterns have been successfully captured for the first time to high accuracy standards, and they do indeed show general trends. Yet the degree of chaotic motion implied by the furrows, and the insignificant correlations of rock and trail parameters, are remarkable. Perhaps the most surprising outcome of this research is the unanticipated lack of order in this natural system. Countless efforts to establish statistically significant relationships between rocks, trails and terrain characteristics yielded disappointing results.

25 posted on 02/22/2012 4:16:34 AM PST by aruanan
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To: umgud

I’ll take glacial deposit for $100 dollars Alex. heh

That’s generally how things got moved around into the strange positions we see them today, although this does look odd even for that.


26 posted on 02/22/2012 4:36:32 AM PST by Bulwyf
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To: umgud; BigCinBigD
"Don't have an answer, but I'm not buying that wind pushed a 660 pound rock."

See post 25. It's funny how NASA refers to a dissertation that flatly denies the claim made in the sentence referring to it.
27 posted on 02/22/2012 4:47:45 AM PST by aruanan
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To: muffaletaman
Visualize a weatherman showing off in a hurricane, and being blown away down the road.

Ice shanties on snow free ice need to be anchored or they will be blown away on high wind days.....

I've had to chase down ice buckets that were blowing away while I was drilling holes for icefishing.

28 posted on 02/22/2012 4:47:54 AM PST by Hot Tabasco (The only solution to this primary is a shoot out! Last person standing picks the candidate)
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To: SunkenCiv

It’s the flying rocks you have to watch out for.


29 posted on 02/22/2012 5:51:20 AM PST by Blogatron (Brought to you by The American Frog Council; 'Frog - The other green meat')
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To: SunkenCiv
God gives us these puzzles to solve. This one is a toughy.

Death Valley taught me one thing. Even water that is hot from sitting in the car tastes very, very good after you've been hiking in 110-degree heat.

It is a beautiful and terrific (in the original sense) place.
30 posted on 02/22/2012 6:21:44 AM PST by TheOldLady (FReepmail me to get ON or OFF the ZOT LIGHTNING ping list)
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To: aruanan

If the ground turns to mud, it never rains enough to wipe out the track behind? Or rains but the wind isn’t strong enough to break the rock free? I can’t see by the pick if there is any water erosion on the trail of the rock, doesn’t look like any to me.

Seems like you would only get that type of thing if every time it rained the rock only moved after the rain stopped. But why wouldn’t the next rain wipe out the track behind? Maybe the rain only moistens the very top level of soil? But then you would think there would be a lot more friction, that looks like a fairly deep furrow. The furrow itself looks like the rock almost scooted along on three points, with places between where the mud is cracked from the heat like the rest of the ground.

Freegards


31 posted on 02/22/2012 6:23:02 AM PST by Ransomed
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To: smokingfrog; umgud

Thanks!


32 posted on 02/22/2012 4:32:43 PM PST by SunkenCiv (FReep this FReepathon!)
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To: Blogatron

/bingo.
Spitzer Sees the Aftermath of a Planetary Collision | Universe Today | Jan. 10, 2005 | Dolores Beasley and Gay Yee Hill | Posted on 01/13/2005 8:50:18 PM PST by SunkenCiv

33 posted on 02/22/2012 8:01:41 PM PST by SunkenCiv (FReep this FReepathon!)
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