99 Years Later... We Solved It 

It's so impressive how the pioneers managed to ride these for miles

I had a book growing up called 'why does a ball bounce and 100 other questions' that was full of physics questions and these stones were in it! It was the only question that didn't have an answer and that always bothered me 😂 now, about 20 years after first reading about them, you have provided the answer. That book was one of the reasons I got into physics and I'm so glad the mystery has been solved. Makes my heart happy in so many ways 😊

I only discovered this channel when the update about your health, done by your friend, came up in my recommended feed. I'm so sorry you're going through such a terrible time and just wanted to thank you for all these wonderful videos. I'm sorry I didn't find them before now! I can't subscribe to your patreon right now so I'm letting all the ads play, watching your videos, in the hopes that every little bit of revenue helps. All the best, Diana, I hope you get better soon xxx

Those are the children/nephews of my geology professor (Dr. Robert Norris). He studied those rocks for decades. I'm surprised he wasn't mentioned. His hypothesis was wind-blown ice sheets, also.

Id like to imagine the rocks just Tokyo drifting across the race track and suddenly stopping when people observe them lol

I did a report on this over 12 years ago in college. The ice sheets with wind was the theory I believed the most. So it's cool they finally got evidence

Sending all my love to you guys. Can't wait to see you back sharing learning and knowledge!

I recognized that ice as soon as it showed it on screen it made sense to me. I live in Michigan and ice like that covers the shore some years

As a young boy back in the 50s my Grandparents had a cabin on the Saltin sea one year the lake was very low and I found a rock that left a trail in the mud. The rock was so large I couldn't move it. I showed my Grandad and he couldn't explain it. I wished he was alive so I could share this with him thank you for sharing ❤

I saw them in 1976. I assumed either the wind was pushing them on very slick sediment that got wet. Or, they were frozen in shallow water ice floes and floated, pushed by wind. I worked at the Nevada Test Site and the dry lake sediment I had to deal with was slick as snot when wet. And I had seen ice move on the frozen dry lake beds. Never put together the gooey silt PLUS the ice. WAY COOL.

I remember reading about this phenomenon in a book about the paranormal in 2013, and I see this video solving it! Thanks for making it :)

I discovered "Physics Girl" just today and watch several videos when I came upon this one. When I was a child (in the sixties) my parents took us on a trip to Death Valley. I remember a wooden sign at the "Race Track" stating it was believed the rocks moved due to water and wind. Having seen many accounts through the years by people amazing at the rocks I would always think to myself "Of course these were pushed by those forces". Not that I had any brilliant thoughts about them, but having been there, I contemplated and observed thinking this now proven theory makes perfect sense. I love it when science proves what attention and "common sense" tells us. I look forward to many more of your vids. Thank you Physics Girl

That video of the rocks moving is pretty spectacular. I wouldn't have believed it could be ice till they filmed it. Crazy dedication.

I remember reading about this in the early 80's with a friend I hung with. We thought it was ice and over the years I had thought had been confirmed a long time ago. We grew up on the shore of Lake Champlain and watched the ice do lots of powerful things.

The pioneers used to ride these babies for miles

Great job on the creation of a well-told story. It is so easy to drift off into the land of dry and dense on STEM topics. This effort is great example for others to follow. Nicely done!

It's thin ice and the wind. I just saved 13mins of your life.

Living in the land of ice near the northern part of the Great Lakes we witness a number of unique ice events. Including wind driving the spring ice amazing distances with perceptible speed along with great force. Separately a Friend of ours has a rock quarry that upon occasion seems to let some large rocks travel as much as a hundred yards without any apparent provocation. Always in the cold season and a bit slower than walking speed. These rocks, sometimes the size of a VW, are usually relatively flat bottomed and move while the ground is frozen with no visible pitch to the ground. One of these rocks weighed close to 50 tons(we know because we were unable to lift it with a 50-ton crane). lce and gravity, amazing stuff.

Thank you for doing such an in depth and thorough job on this video. I've always been fascinated by this mystery and you have presented the answer in a comprehensive way. And your footage is spectacular! I have subscribed🙂🙏

What most puzzling to me is the weight of the rocks and how it only takes very little to actually move them. You’d think they’d stay put because of their weight!

This is so amazing to me. I remember years ago learning about the sailing rocks. The "latest science" was that it was wind that pushed the sailing rocks across the play. I think it was in the 1990s. Back then, in the documentary, I remember that they ruled out ice. Really awesome that 30 some years later they determine it was ice and wind.

I remember learning about this years ago. I love this experiment because it’s a great example of humans trying to make sense of evidence found. As much as we think outside the box, sometimes we just need to sit and wait and let nature teach us a few things.

That's amazing! I was there in 1997/1998 and visited The Racetrack, and had heard about the moving rocks before going there. It was incredible to see them in-person, and now it's good to know what caused their movement!

Fascinating! Thank you for investigating this phenomenon for all of us to learn about, Dianna!

I took a Geomorphology class at NAU a few years ago, and we were on a week long field trip in Death Valley. On our last night, we camped in a playa outside of the park. When we got there, we ran into these two when they kindly asked us to make sure we weren't doing donuts in the playa where they were about to film a german documentary for PBS. They were incredibly nice, and even showed us their GPS equipment that they used to track the rocks, and gave us an explanation of the whole process. I recorded a video of their talk and have been meaning it to upload it to RU-vid ever since. It was SO cool to be in the presence of the actual scientists who discovered this mechanism.

I remember hearing about rocks being moved by icy winds on salt water dry lakes because the wind would hit one side of the rock, freeze the water on that edge, the ice would expand and lift the rock, then more ice would get under it and eventually it would be enough to lift the rock and move it a tiny tiny bit. Then the ice would melt and the rock would have moved and no one knew why

Wow, I had only heard of this thanks to you guys and RU-vid, and thanks because it's very interesting! It's amazing that a bit of ice, water, and wind can push even really big rocks like this without the wind having to be tornado- or hurricane-force! And what else is interesting is that someone tried really hard to solve this curiosity even though it wasn't causing a problem while staying unsolved. Thanks for sharing!

Very interesting! I've wondered about those tracks in the sand. This explains it. Thank you.

I remember traveling through Death Valley on vacation with my family and being really fascinated by the phenomenon! Really cool to see a conclusion to a scientific mystery that I've seen in person!

My old teacher told me 40 years ago that the surface needed to be wet. The ground is too dry and hard to get those Mark's unless the ground was very wet. He had no idea why/ how they actually moved though!

In Kansas there is a place called monument Rock. I was there after it snowed. I noticed the snow would roll up the monument. Me and a buddy figured maybe the monument rocks were actually at a slant or something. But never could figure out why the snow would literally roll up into like a snow log and roll up the monument on their own. It was wild

Aristotle: "These stones want to move elsewhere but they are old and slow".

I remember reading about this when I was very young (possibly at school), I'm nearly 60 now. It's great to finally hear the explanation (I missed it between 2014 and now), still it's good to get closure. Thanks physics girl.

Just before Easter in 1986, I watched a light breeze push the winter ice off Lake Wallenpaupack in Pennsylvania. I walked on to the ice that had reached dry ground and rode it as it slowly pushed ashore, piled up and broke into flimsy shards and ice straws. The ice pushed a huge nearby boulder through the sand and mud, leaving a trench about eight feet wide and three feet deep. I could reach into that rotten ice and crush it so easily in my hand, but the massive force exerted by a light breeze on the surface of a couple of square miles of ice was absolutely unstoppable and awesome to see.

Error: Winds do not push down against the water as drawn in your seiche event diagram. Rather, winds at a smooth horizontal surface like a lake or lakebed ALWAYS travel horizontally, even in a hurricane or tornado. Your green three arrows of wind should be horizontal, not drawn at a 45 degree angle. Instead, horizontally-blowing wind creates a sheer force with the lakes surface, which leads to a surface current and higher water elevations on the leeward side of a lake than on the windward side. It's not the dramatically lower pressure which pulls water at the eye of a hurricane upwards, resulting in water levels several feet higher than MSL +/- tide, although it does have some effect. Rather, it's the horizontal surface winds blowing around and towards the eye of the hurricane which drag ocean water towards the center. That warm air then rises in the hurricane's heat engine, fueling the hurricane's activity. For example, standard day pressure is 29.92 in Hg. The lowest recorded hurricane pressure was 26.0454 in Hg, for a difference of 3.8746 in Hg. That translates to 4.3908 foot of head, meaning it'll draw up 4.39 feet of fresh water. Due to ocean water's higher density, however (1,023 to 998 kg/cu m) that only comes to 4.28 feet of head for seawater. The rest of the storm surge is ALL driven by horizontal winds!

Communication during an inner turmoil has set up a home in my mind, days or even years later i find myself struggling with how i had failed myself and others in messaging in an appropriate manner, when those situations arise, I've learned to best stay quiet when unsure about how to properly state my thoughts!

I think there's one other factor in the rock movement. Notice the picture at 8:51. It appears that in addition to ice forming, the water turns the base into mud, making it even easier for the rocks to be dragged along by the ice.

At 6:13 in the video, several papers are shown. John Reid, the first author of Sliding Rocks of Death Valley: What makes them move? was my advisor at the time (1995); the other authors were fellow students. I was not part of the research team, but as a student at a collaboratively oriented college , I did participate in discussions and making the calculations presented in the manuscript. To my knowledge, it was the first time large scale detailed measurements were made and the required wind shear forces were calculated and resolved with the mechanism of wind shear on a large ice sheets and reduced friction of the rocks on wet mud , and the conclusions were fundamentally correct. Notable in that publication is mapping that demonstrates that rocks moved in groups that would divide into subgroups, an observation that necessitates either ice sheets or divine intervention to accomplish! The contribution of the research by the Richard and James Norris is to irrefutably demonstrate the findings of that research with technology not readily available 25 years ago. It is important to give all credit where credit is due. The contribution of the Norris' work is wonderful, and it satisfying to see the phenomenon that we understood 25 years ago so elegantly proven. I think it would be more accurate although perhaps less sensational to say that they provided the unequivocal proof of research that solved the mystery in 1995. Congratulations to all!

I read articles about this mystery when I was much younger, and it's cool to see that someone has managed to solve it.

Fascinating. I guessed wind but like everything in life, it's more complicated than one thing. Thank you. Kudos also to the videography. I appreciate talented videographers dedication their work to science. Subscribed.

I'm a retired science teacher and an article about these rocks was in one of our textbooks at some point or, I think, maybe I clipped an article from "Discover" or "Science Digest" magazine and used it in my classroom. I'm not sure now. But this was always something that we talked about and I presented it to my students as a mystery that needed to be solved. I'm so glad to hear that there is a reasonable explanation now! Also, it warms my heart to know that the girl in Germany did a science fair project on this. I always had my students enter the regional and state science fair and my own daughters received college scholarship offers due to science fair!

I've made many trips to Death Valley over the years, and my favorite place is definitely the Racetrack Playa. It's fantastic to see the "mystery of the rocks" solved in this video. I always felt that it had something to do with the playa becoming wet and slippery, but "ice" never occurred to me. I will also say, to anyone who'd like to make the trip, yes, it's long way, and lots of driving, but it's well worth the effort and somewhat life changing. There's an energy that stays with you, when you see the rocks with their long tracks and also see the Grandstand in the distance. One tip, which I learned to help prevent getting your tires punctured on the gravel roads in and around the area, is to take out about 15-20% of the air in your tires. This will soften the tires, and will allow them to flex a bit more when driving over jagged rocks. This flexing, will prevent the rock from puncturing the tire tread. And once back to Stove Pipe or Furnace Creek, you can refill the tires with air, or carry cans of air, which are easily bought at a car parts store. Works great, and I have never had a flat!

I was intrigued as soon as I saw the title and subject of this video, and I have enjoyed this presentation greatly. This is just amazing!

Physics Girl is in a very serious way. Any help or donations you can send her would be great.

Rocks should be free to amble around without their motives being questioned. 😅

the literal "perfect storm" of environmental conditions that had to happen at this specific place in the world for the rocks to move is just insane, makes perfect sense that it took so long to figure out

Accidentally stumbled on to this video and channel. I'm hooked and subscribing to Physics Girl. Everyone in this video is really cool. Even the rocks.

I used to go to Death Valley with my dad when I was a teenager and that was definitely an odd thing. My dad was being a dad with all of the answers, .. but couldn't explain that one. Thank you for posting this physics girl!

I used to fly over this valley while doing low level flights for the Navy. I was always amazed to see the mysterious rock trails from the air. Very cool to learn how they were made!

I live on the shores of Lake Erie. Seiches are somewhat common. They are incredibly powerful and destructive. The lake can rise 8ft in just hours. This seems easy for a mini-seiche.

I've always heard of these "moving rocks," but never knew why they did that. Thanks to you (and that 13 y.o. girl) it's a mystery no more. Great video!

Thanks for this, it is a real example of curios and smart person that resolve a question, it can help to explain other situation

i love how their approach was literally "let's put imposter GPS tracked rocks among these moving rocks to see how they do it"

“Its not just a boulder it’s a rock” and “ The pioneers use to ride these for miles” - SpongeBob

I remember as a kid, seeing this on a National Geographic show thinking that it must be wind. They said the rocks were very heavy. I found it very interesting and nice to have the mystery solved.

Love your presentation and evaluation. Just brilliant

When I started shooting photos at Racetrack in the early 2000s, there were almost no footprints or signs of people disturbing the playa when it was wet. Since the huge social media explosion, and all of the attention brought by the explanation, it's now almost impossible to find rocks without footprints around them. Please - if you want to visit the playa, don't walk on the surface if it's at all soft - your footprints will ruin it for everyone else that comes after you for decades. Kudos to them for solving the mystery, but every time I see something else published about this place, I know it means it will never be the same again...

12:00 yeah he's right. Saline water is more dense than non saline water and this demonstration has already proven it only takes millimeters. So a very thin layer of fresh water may form on the surface which would be more than capable of moving exposed stones.

I'm so happy this mystery had been solved in my lifetime I really appreciate geologist now very personal feeling of knowing something truly interesting

I was stationed at Edwards Air Base in the early 1970s which had 2 dry lake beds and the same phenomenon occurred. The explanation then was wind moving the rocks when the rare rains occurred. Similar environment, high desert and very windy.

So glad I found your channel! Really interesting. When I was 15 years old, very interested in sailing and boats, my uncle asked me 'if a ship is made out of steel, how does it float?' I couldn't really answer him at the time. I learned about displacement later, while studying boat design. Looking forward to watching more of your videos.

So cool to finally be able to understand this mystery. I must have been around 10 or 11 when I first heard about these rocks in Death Valley. There were all kinds of theories but it takes determination to figure some things out and these guys did it! Awesome!

I always love how things that people couldn't explain in the past, and that generated all kinds of crazy stories to explain them, end up getting solved when scientists carefully study the problem and find a perfectly reasonable scientific explanation to put it to rest.

Get better please!

When talking about geology, it's amazing how fast these actually move!

Ice is incredibly strong laterally. Working on a dredging barge I found that 1/8th inch of ice can stop 50 tonnes of tugboat assisted floating steel.

I have a relative who is a tenured physics professor at University of Wisconsin at Stout, in Menomonie. She teaches physics to non-physics students, and her explanation of physics could make even me understand it (I will be 80 in July, 2024, and have a learning disability with numbers, so even basic math is most of the time very difficult for me). She is very active in promoting STEM for young female students. I am proud to be related to her.

SpongeBob was right. The pioneers could’ve rode those rocks for miles

I recall these rocks being featured on the tv show THE MYSTERIOUS WORLD OF ARTHUR C CLARKE. I do not remember how it was explained but I think it was thought to be the wind. The rocks may also have been on a tv show called IN SEARCH OF. It was hosted by Star Trek's Leonard Nimoy. A commenter below said the rocks were also in an UNSOLVED MYSTERIES episode.

My father, Allen F. Agnew, wrote his PhD Dissertation on this phenomenon while earning his Doctorate at Stanford University in either 1946 or 1947. Sadly, he died about two years before the actual cause was resolved, finally. Mom and Dad lived near there, in Death Valley, for three summer months, in a small, one-room cabin, while Dad did his research. That is where Mom was given the nickname "Watery Eyes" and Dad earned "Pealy Face". Allen B. Agnew (B for Boy, F for Father, eh?)

I hope you’re doing okay Diana you're video popped up on my feed and I remembered what happened to you and just wanted to say I hope you’re doing OK. I hope you can fully regain you’re strength and happiness again ✌️❤️😉🙏

That was incredible, well told!

Outstanding video PG! 👍 I always thought that the high wind/wet playa theory had some holes in it even though a wet playa can be incredibly slippery. I saw moving sheets of ice destroy a boathouse once. Very destructive even at low speed.

This was wonderful 🤓 What an interesting backstory, setting, and of course the answer itself. Crazy this eluded people for so long. Such a great video.

So my curiosity didn't disappoint. This was fun. Thank you! Looking forward to learning more stuff. I will continue my rabbit hole in this channel with less caution now.

Get well soon Dianna! Can't wait to see you back 👍

Once you see the solution you say, "Of course , how simple!" That's good science in action, easy when you know how!

Hi! Very interesting! Of course one factor that makes it easier for the thin ice to move the rocks is that the surface they are being pushed on does become very slippery. Looks like a fine particulate mud forms on the pia. It's a chilly slip and slide! I always thought it took thousands of years caused by temperature contractions in the rock, but no!

I've seen this story before but it was so far back in the day that no one knew what was going on I didn't even know but now I do thanks to your video thank you

I lived as a child on a large northern lake. When the surface ice melts in the spring the first place it disappears is at the shorelines. Then if you have a stiff wind heading southward the surface ice moves up on the south shoreline. At the same time the gap of water on the north shoreline expands. If you are an ice fisherman your ice hole heads south as well.

Hearing the ice explanation, reminds me of when I was installing docks on a local lake. On a calm night a 1/4 inch thick sheet of ice formed. Well when we started in the morning the wind was out of the north, a couple of hours later the wind shifted to the south. We being on the north shore soon seen the ice moving our way. I tried breaking the ice as it moved our way (I'm in the water) and soon I had to get out of the water because it was knocking me over! And soon all the 4×4posts we had pounded into the bottom were getting knocked over!

When my geology class in college back in (mumbled year some time in the last millennium) went to Death Valley, we surmised that it had to be a combination of heavy flooding and heavy winds occurring simultaneously. The real answer was more fascinating.

Watching the ice move around the great Southbay in New York. I could see how the coves are formed. They push a lot of sand and pile up 10 to 15 feet high on the beach. One year the ice piled up about 15 feet high and the last sheets stayed solid, and we went sledding. Down it how fun it was.

I just found this Awesome channel! I really hope you feel better. Thank you to everyone that is helping!

I didn't realize that someone had actually solved it. I live in Michigan I can tell you when the ice comes on shore (as shown in the video) it is amazing what destruction it causes.

Like the big Stones in the Netherlands and North Germany. They build "hunebedden" with them. Huge graves. Ice is powerfull. Great story!

i cannot d oanything but thank youtube for making this pop out in my home... This video is so well-made that when i checked your sub count i was surprised in negative. If all of your videos are even just remotely close to this, your channel may be a good comparison to veritasium, which I deeply admire. Loved this way more than expected!

Seeing them standing there with the sign at the end was so great. So happy this finally got solved, and someone made such a good video about it.

Back in the 1970's I saw a PBS TV documentary pertaining this mystery of heavy rocks leaving trails in the middle of nowhere. Well about 4 years ago I went trail bicycling in the Imperial Valley's south California desert area. Just across the famous Salton Sea , near the inland Border Patrol Inspection on Highway 86 there is the Juan Bautista de Anza National Historic Trail . And out in the middle of nowhere in this trail I saw these medium size boulders and rocks that had left trails behind them . I did take photos of this . Now I know how these heavy stones and rocks moved to leave trails behind them .

i saw an ice dam blown up the shore of lake manitoba destroy a small housing development by portage la prarie...or was it lake winnipeg? i cannot be botherd to look it up.

Get well soon

I remember debating in several different science classes during school, all the different ways the rocks could have been moved. Pretty neat that someone finally solved it.

I remember seeing these rocks in books as a kid. Great to find out why 🙏

"Most replayed" at 06:05 me: huh what was there? me: *watches* me: 👁👄👁 me: oh yeah it totally must be because of the papers.

I am glad the mystery of sailing rocks was finally solved with proof to confirm it! Congrats to them!

I remember this mystery from my childhood and remember the many theories that surrounded it. I'm so impressed with the collaboration of these scientists and their tenacity to discover the answers and the truth. Each understanding of our natural world brings us closer to it. Thank you for sharing this!

My Geology professor Dr. Stanley at Fresno State solved the mystery in the 50s. He showed our class his research in 1963. It was the same explanation as given in the video. He solved the mystery without any of the modern technology used here.

i wanna say, i love how the title and thumbnail are perfectly captivating yet not clickbait, almost no one can do that

Always enjoyed the race track. Cool deal - nice job guys.

I've heard about these mysterious moving rocks several years ago and it has always rattled around in my head about what caused this phenomenon. Thanks for stopping the rattle.