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It`s Okay To Be Smart, The Self-Organizing Secret of Sand Dunes

The Self-Organizing Secret of Sand Dunes

Hey smart people, Joe here. But why is this here?

Sand dunes are basically big piles of sand. They're formed by the interaction of sand

with wind. But that's kind of confusing, right? I mean, if wind blows across sand,

wouldn't you expect something way different to happen?

When air blows across sand maybe you'd expect it to spread that sand out into… nothing

special at all. But that isn't what happens.

This is.

At the smallest scale, delicately traced ripples and ridges no more than a centimeter high.

And at the largest scale, oceans of wave-like dunes up to hundreds of meters high. So…

how do they form? Sand dunes are one of nature's most incredible

examples of order, and even beauty, arising out of, well, chaos.

Beautiful sand dune landforms like this form in countless places around the world. And

they all happen from the same few ingredients: wind, time, and trillions and trillions of

pieces of this stuff. And all of that creates the beauty of physics on the granular and

the grand scale. Now, to make some shape like this—what geologists

call landforms…

you have to take stuff from one place, move it, and put it somewhere else.

Or technically speaking: erosion, transport, and deposition.

The key to sand dunes is what's doing the moving, and what's getting moved.

Sand is a paradox. It's solid. I mean, I'm sitting on it. But it can also flow like a

liquid. And sometimes, even behave a little bit like a gas.

Sand is weird stuff! And that weirdness is what causes it to form these patterns and

shapes.

But, like… what IS it? Sand is just a special kind of dirt, right? WRONG.

Sand is so much more than that! It's a record of millions of years of wind

and water that have carved their way across the surface of our planet: Mountains, rivers,

and deserts long gone.

It's… it's, you know…

that stuff. The thing about sand is it isn't defined

based on what it's made of.

It's defined based on the size of the particles. Anything between 1/16th of a mm and 2 mm?

That's technically sand.

The sand many of us are used to is tiny pieces of quartz that've been broken down from

bigger rocks. But volcanic ash can be sand too.

Or gypsum, like the famous White Sands of New Mexico.

Some sand is really ground up coral or seashells.

Even the skeletons of plankton!

Small snow crystals can even technically be sand.

But maybe the strangest kind of sand on Earth comes from the beaches of Normandy, where

the D-Day invasions of WWII took place. They're covered in microscopic particles of shrapnel

known as “war sand”.

So. What is sand? It's just really small stuff. Not like the very smallest stuff. But

still really small. That pretty much covers it.

And that Goldilocks size (not too big, not too small) lets sand move in a way that nothing

else really does.

Big stuff, like rocks… wind doesn't do much to them.

Slightly smaller stuff like gravel, if enough wind hits it, might do this.

The very smallest stuff, like dust, gets swept into the wind and stays there.

Sometimes traveling thousands of miles before it lands again.

Sand is just small enough to be lifted and swept along by the wind, but big enough that

it doesn't stay up for long.

This bouncing is what happens as sand is blown by wind across arid desert-like surfaces,

though it's difficult to see with the naked eye.

Sit down near a sandy surface on a windy day, though, and you'll definitely feel it

If you've ever looked at any sand-covered surface that's been shaped by wind, you've

probably noticed these evenly spaced, repeating ridges or ripples of sand, usually a few centimeters

apart.

And these are another paradox. How does this turbulent cloud of bouncing, chaotic sand

create… order? I think by far the coolest thing about the

dunes, it isn't the dunes themselves, it's these patterns that form on the surface of

the sand.

you'd think if the wind were blowing across this sand, you'd just end up with a nice

smooth surface, it'd just even everything out. But that's not what happens.

These beautiful ripples, they're almost like “fingerprints” of the sand dune.

I mean, it looks like someone came out here with a rake and made these. But what is so

amazing about these ripples, is they form themselves. They organize themselves, out

of just wind and sand.

So how do these ridges form?

Well once a grain of sand is lifted into the wind and dragged along, when it hits the sand

surface again, it almost splashes, driving more grains of sand up into the wind.

But the distance of those hops isn't random. It depends on how big and heavy the grains

are and how fast the wind is moving. And this is likely the key to why these ripples form.

So this feedback loop of bouncing sand begins to form on the surface. All it takes is a

little random spot where a few more grains of sand land than others. And that creates

a little hump, which causes even more sand to land there. And a little shadow behind

that hump where less sand is landing.

That pattern repeats itself all the way down the row. Again, just based on the size of

the grains of sand and how far they bounce in that wind.

Bouncing sand, pulled along by the wind… self organizes to make this.

The size and distance between these ripples can be different in different conditions:

different wind, different sized sand = different ripples.

And if we speed up time, we can even watch those ripples move.

Much of what is known about how sand and wind interact to form dunes is thanks to this man:

Ralph Bagnold. An explorer and brigadier in the British army, he was stationed in North

Africa between WWI and WWII.

In 1929 he completed an expedition in search of a mythical oasis city called Zerzura, crossing

the sand seas of the Libyan desert in a caravan of Ford Model A cars.

His partner on that expedition was a Hungarian adventurer named László Almásy, who was

later made famous in the film The English Patient, where he was played by Voldemort.

Bagnold never found that mythical oasis, but he did discover the foundations of Aeolian

processes, that's the technical term for how wind shapes land through moving sand and

sediment, named for the Greek god of the wind.

And his 1941 book is still used today. It's a bit dry,

but what do you expect for a book about sand?

Thank you, thank you.

It's pretty awesome that in a system that seems like random noise—bouncing sand, it's

like the physical version of TV static—even there, patterns do, in fact, exist.

Creating order on small scales…

and large

Sand dunes can range from a few meters high to towering, sculpted mountains hundreds of

meters tall. Like these at Great Sand Dunes National Park in Colorado, where I decided

to climb them.

Like ripples, dunes are also formed by the interaction of wind and moving particles…

But sand dunes happen for a completely different reason. It's not just sand colliding with

other sand, this is aerodynamics.

When wind flows over an obstacle, like a large bump of sand, it speeds up.

This is why winds are often much stronger on top of hills…

Dunes form when wind accelerates over an obstacle, eroding sand as it goes. What's weird is

the spot on the hill where the wind is pulling hardest on the sand, where the most erosion

occurs, it isn't here at the top, which is what you might expect. The most erosion

happens here on the windy side of the dune. Those grains bounce up the hill, pulled by

the wind, and get dumped at the crest of the growing pile. So the dune can grow.

Because the sand gets eroded the most here, and not at the top, that's the reason dunes

exist instead of getting blown away by the wind.

So as the wind comes up the front side of the dune, eroding sand, it deposits it here

at the crest. Then something weird happens. You can't stack sand forever. Once the angle

of that stack gets to be 33 or 34 degrees, you get an avalanche. You can try it yourself

at home.

Look at this finely powdered sugar. It's almost like dust. Because all those small

particles can pack in with each other and be nice and comfy, it can be stacked to super-steep

angles without avalanching. Nearly vertical even!

But larger granular materials, like this table sugar, which in this demonstration represents

sand, they avalanche at a much shalloEwer angle, because they can't pack as tightly.

And you can see that right behind me. This line is the palace where avalanche after avalanche

have occurred, shaping this side of the dune.

Anybody have a protractor? Anybody? Should have brought one. Measure it.

Some really interesting things happen right at the top too. The air passing over the dune

will try to follow the curve of the dune.

The same way that liquid will flow down the side of a cup if it's poured too shallow.

But if the flow is faster, and the surface peels away really sharply, like it does thanks

to that avalanche angle, the air detaches and can't follow, just like how water poured

from a spout pours into our cup and doesn't flow down the side.

The wind is clearly blowing sand off the top of the dune, but as long as the wind from

upstream keeps depositing more sand at the top than gets blown away, the dune won't

shrink.

As sand piles and avalanches, the whole dune may even move or migrate,

over months or years.

Dunes can grow to ridiculously large scales. The ones I climbed were more than 700 feet

above where I started.

Many dunes are even visible from space! And from that perspective I think you get the

clearest view that there's obviously another level of order arising from the chaos and

turbulence of sand blowing in the wind.

And that order comes in many different shapes. The shape of a dune tells us about the wind

that created it. This is a transverse dune. A barchan dune. A longitudinal dune. And a

star dune. Just a few of the shapes that dunes can take.

Why Care? Let's be real for a sec. Some of you are

probably saying, “hey Joe, why should I care about wind blowing a bunch of sand around?”

And to that I say “Knowing stuff is awesome.”

And also because moving sand impacts a lot of people's lives.

As temperatures rise on Earth and our population expands, urbanization, mining, farming, and

deforestation are degrading lands into dry, desert-like landscapes. It's called “desertification”,

and every year, an area equal to half the European Union deteriorates into dusty, scorched

Earth. Climate change will only speed that up.

30% of Earth's surface could end up drying out, affecting billions of people.

And as erosion increases, dunes may threaten to bury whole towns.

Towns like the tiny spaceport of Mos Espa, in Tunisia, slowly getting swallowed by a

giant moving sand dune.

Ok, that's actually the set they built for Star Wars: Episode I, but it'll happen to

real places too! In fact, it was the threat of sand dunes overtaking

a coastal town in Oregon that inspired one of the greatest works of science fiction ever

written.

A young newspaper reporter was sent to investigate how engineers and ecologists were fighting

to keep migrating dunes from swallowing roads, bridges, and houses.

The story he was sent to write was never written, but a few years later, he wrote a book you

may have heard of: Dune. Watch out for sandworms, kids! Never know

when you're gonna run into one of those things.

In that story, the complex interplay of life and sand on the desert world Arrakis is threatened

with collapse at the hands of humans.

It's a lesson about appreciating the delicate balance and the forces of nature. A warning

about our own planet. But also a hint that what happens here on Earth, happens elsewhere.

You see, our planet isn't the only planet with dunes.

We find sand dunes on Mars, with unique ripples and hills shaped by the thin atmosphere and

constant winds of the red planet. Dunes on Saturn's moon Titan, made of frozen hydrocarbons.

Even dunes of frozen methane on Pluto. It's pretty likely that every solid thing

in our solar system or others has some fine-grained stuff on its surface, something sand like.

So wherever there's an atmosphere that can move that grainy stuff, patterns like ripples

and dunes will also form there. These patterns are fingerprints left by a planet's past,

ours and others.

So why care about big piles of sand?

Well, because they are beautiful. Because it feels good to understand why something

is the way it is, not just how it is. And because they are an incredible example of

self-organization and patterns formed by physics alone. But also because something as simple

as wind and sand can inspire us to think about something a bit bigger.

I think I finally understand what the poet WIlliam Blake meant when he wrote:

To see the world in a grain of sand, and heaven in a wildflower,

hold infinity in the palm of your hand, and eternity

in an hour.

Stay curious.

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The Self-Organizing Secret of Sand Dunes ||организующие|Секрет|||дюн ||||||Sanddünen Das selbstorganisierende Geheimnis der Sanddünen The Self-Organizing Secret of Sand Dunes El secreto autoorganizativo de las dunas de arena Le secret de l'auto-organisation des dunes de sable Il segreto dell'auto-organizzazione delle dune di sabbia 砂丘の自己組織化の秘密 모래 언덕의 자기 조직화 비밀 Smėlio kopų saviorganizacijos paslaptis Het zelforganiserende geheim van zandduinen Samoorganizujący się sekret wydm piaskowych O segredo de auto-organização das dunas de areia Самоорганизующийся секрет песчаных дюн Sanddynernas självorganiserande hemlighet Kum Tepelerinin Kendi Kendini Düzenleyen Sırrı Секрет самоорганізації піщаних дюн Bí mật tự tổ chức của cồn cát 沙丘的自组织秘密 沙丘的自组织秘密 沙丘自我组织的秘密

Hey smart people, Joe here. But why is this here? ||||||почему||| |schlaue||Joe hier|||||| |||Joe|||||| أيها الأذكياء، جو هنا. ولكن لماذا هذا هنا؟ Hallo kluge Leute, hier ist Joe. Aber warum ist das hier? Hola gente inteligente, Joe aquí. ¿Pero por qué está esto aquí? Ehi gente intelligente, qui Joe. Ma perché è qui? Ei, pessoas inteligentes, Joe aqui. Mas por que isso está aqui? Эй, умные люди, это Джо. Но почему это здесь? Hey akıllı insanlar, Joe burada. Ama bu neden burada? Này những người thông minh, Joe đây. Nhưng tại sao nó lại ở đây? 嘿聪明的人,这里是乔。但为什么会在这里?

Sand dunes are basically big piles of sand. They're formed by the interaction of sand |||||кучи|||||||взаимодействия|| Sand|die Dünen||||||||||||| |||||山||||||||| الكثبان الرملية هي في الأساس أكوام كبيرة من الرمال. لقد تم تشكيلها من خلال تفاعل الرمال Sanddünen sind im Grunde große Sandhaufen. Sie entstehen durch die Wechselwirkung von Sand Las dunas son básicamente grandes montones de arena. Se forman por la interacción de la arena Dunas de areia são basicamente grandes pilhas de areia. Eles são formados pela interação de areia Kum tepeleri temelde büyük kum yığınlarıdır. Cồn cát về cơ bản là những đống cát lớn. Chúng được hình thành do sự tương tác của cát 沙丘基本上就是一大堆沙子。它们是由沙子相互作用形成的

with wind. But that's kind of confusing, right? I mean, if wind blows across sand, ||||||||||||дует|по| |||||||||||vento|sopra||com vento. Mas isso é meio confuso, certo? Quero dizer, se o vento sopra através da areia, مع الريح. لكن هذا نوعاً ما مربك، أليس كذلك؟ أعني، إذا هبت الرياح عبر الرمال، con viento. Pero eso es un poco confuso, ¿verdad? Quiero decir, si el viento sopla a través de la arena, 風で。でも、それはちょっと紛らわしいでしょ?つまり、風が砂の上を吹くとしたら com o vento. Mas isso é um bocado confuso, não é? Quero dizer, se o vento sopra na areia, с ветром. Но это как-то сбивает с толку, верно? Я имею в виду, если ветер дует по песку, Ama bu biraz kafa karıştırıcı, değil mi? Yani, eğer rüzgar kumun üzerinden esiyorsa, với gió. Nhưng đó là loại khó hiểu, phải không? Ý tôi là, nếu gió thổi qua cát, 有风。但这有点令人困惑,对吧?我的意思是,如果风吹过沙地,

wouldn't you expect something way different to happen? разве||||||| ألا تتوقع أن يحدث شيء مختلف؟ ¿no esperarías que ocurriera algo muy diferente? 何か違うことが起こると思わないか? não seria de esperar que acontecesse algo muito diferente? Разве вы не ожидаете, что произойдет что-то иное? çok daha farklı bir şey olmasını beklemez miydiniz? bạn sẽ không mong đợi điều gì đó khác biệt xảy ra chứ? 你不希望发生一些不同的事情吗?

When air blows across sand maybe you'd expect it to spread that sand out into… nothing ||||||вы||||||||| ||||||||||espalhar||||| عندما يهب الهواء عبر الرمال، ربما تتوقع أن ينشر تلك الرمال إلى... لا شيء Cuando el aire sopla a través de la arena tal vez se espera que se extienda la arena en ... nada 空気が砂の上を吹き抜けると、その砂は......何もないところに広がっていくと思うだろう。 Quando o ar sopra sobre a areia, talvez seja de esperar que espalhe essa areia em... nada Когда воздух дует по песку, возможно, вы ожидаете, что он рассеет этот песок в… ничто. Hava kumun üzerinden estiğinde, belki de kumu hiçbir şeye yaymamasını beklersiniz... Khi không khí thổi qua cát, có thể bạn sẽ cho rằng nó sẽ thổi cát đó ra thành… hư không 当空气吹过沙子时,您可能会期望它会将沙子散开成……什么都没有

special at all. But that isn't what happens. |||||||происходит خاص على الإطلاق. ولكن هذا ليس ما يحدث. especial en absoluto. Pero eso no es lo que ocurre. まったく特別なことだ。でも、そんなことは起こらない。 especial de todo. Mas não é isso que acontece. вообще особенный. Но это не то, что происходит. 特别的。但事实并非如此。

This is. Así es. これがそうだ。 Это так. 这是。

At the smallest scale, delicately traced ripples and ridges no more than a centimeter high. ||||деликатно||волны|||||||| ||||||ripples|and|small elevations|||||| |||escala|delicadamente|traçadas|ondulações||sulcos|||||| |||Maßstab|delikat ausgeprägt||Wellen||Rippen|||||| ||||섬세하게|그려진|물결||능선|||||| ||||繊細に|描かれた|波紋||隆起|||||| ||||||ondas||crestas|||||| على أصغر المقاييس، تم رسم التموجات والتلال بدقة لا يزيد ارتفاعها عن سنتيمتر واحد. Im kleinsten Maßstab, fein gezeichnete Wellen und Rillen, die nicht höher als einen Zentimeter sind. En la escala más pequeña, ondulaciones delicadamente trazadas y crestas de no más de un centímetro de altura. À l'échelle la plus petite, des ondulations et des crêtes délicatement tracées ne dépassant pas un centimètre de haut. 最も小さなスケールでは、高さ1センチにも満たない波紋や隆起が繊細にトレースされている。 Op de kleinste schaal fijn getraceerde rimpelingen en richels van niet meer dan een centimeter hoog. Na escala mais pequena, ondulações e cristas delicadamente traçadas com não mais de um centímetro de altura. На самом маленьком масштабе, нежно очерченные ряби и гребни высотой не более сантиметра. Ở quy mô nhỏ nhất, những gợn sóng và đường gờ được vẽ tinh vi cao không quá một cm. 在最小的尺度上,精致的波纹和脊线不超过一厘米高。

And at the largest scale, oceans of wave-like dunes up to hundreds of meters high. So… |||||||волноподобных|||||сотен|||| |||||||ondas|como|dunas|de|||||| وعلى نطاق أوسع، توجد محيطات من الكثبان الرملية الشبيهة بالأمواج يصل ارتفاعها إلى مئات الأمتار. لذا… Y a mayor escala, océanos de dunas onduladas de hasta cientos de metros de altura. Así que... Et à plus grande échelle, des océans de dunes en forme de vagues pouvant atteindre des centaines de mètres de haut.... そして最大のスケールでは、高さ数百メートルにも及ぶ波のような砂丘の海。つまり... А на самом большом масштабе, океаны волнообразных дюн высотой до сотен метров. Так что…

how do they form? Sand dunes are one of nature's most incredible |||образуют|||||||| |||||모래언덕|||||| |||||||||自然の|| ¿cómo se forman? Las dunas de arena son uno de los fenómenos más increíbles de la naturaleza. como é que se formam? As dunas de areia são um dos fenómenos mais incríveis da natureza как они формируются? Песчаные дюны — одно из самых невероятных мест природы

examples of order, and even beauty, arising out of, well, chaos. ||||||возникающей|||| ||||||entstehend|||| ||||||生まれる|||| ||||||||||caos příklady řádu, a dokonce i krásy, vznikající z chaosu. ejemplos de orden, e incluso belleza, que surgen del caos. des exemples d'ordre, et même de beauté, naissant du chaos. 秩序、そして美しささえも、カオスから生じている例だ。 voorbeelden van orde, en zelfs schoonheid, die voortkomen uit, nou ja, chaos. exemplos de ordem, e mesmo de beleza, que surgem do, bem, caos. примеры порядка и даже красоты, возникающие из хаоса.

Beautiful sand dune landforms like this form in countless places around the world. And ||дюна||||||||||| ||Düne||||||||||| |||shapes of sand|||||||||| ||砂丘|地形|||||||||| |||formações de relevo|||||incontáveis||||| En innumerables lugares del mundo se forman bellas dunas como ésta. Y Em inúmeros locais do mundo formam-se belas dunas de areia como esta. E Красивые формы рельефа песчаных дюн, подобные этой, образуются в бесчисленных местах по всему миру. И

they all happen from the same few ingredients: wind, time, and trillions and trillions of |||||||||||триллионов||| |||||||||||수조||| |||||||||||||trilhões| todos se producen a partir de los mismos pocos ingredientes: viento, tiempo y billones y billones de todos eles acontecem a partir dos mesmos ingredientes: vento, tempo e triliões e triliões de

pieces of this stuff. And all of that creates the beauty of physics on the granular and |||вещи|||||созит||||физики|||гранулярном| ||||||||||||物理学|||粒子状| pedaços||||||||||||pedaços dessa coisa. E tudo isso cria a beleza da física em nível granular e|||partículas| trozos de este material. Y todo eso crea la belleza de la física en el granular y stukjes van dit spul. En dat alles creëert de schoonheid van de natuurkunde op het korrelige en... pedaços deste material. E tudo isto cria a beleza da física a nível granular e куски этого материала. И все это создает красоту физики на гранулированном и шматочки цього всього. І все це створює красу фізики на гранулярному та

the grand scale.  Now, to make some shape like this—what geologists |огромном|||||||||| |||||||||||地質学者 |grande||||||escala grandiosa. Agora, para fazer alguma forma assim—o que os geólogos|||| la gran escala. Ahora, para hacer alguna forma como esta-lo que los geólogos 壮大なスケールである。さて、このような形状を作るには、地質学者は次のように考えている。 de grote schaal. Om nu een vorm als deze te maken - wat voor geologen? a grande escala. Agora, para fazer uma forma como esta - o que os geólogos грандиозный масштаб. Теперь, чтобы придать такую форму, какие геологи грандіозного масштабу. Тепер, щоб зробити якусь фігуру на зразок цієї - те, що геологи

call landforms… называют| |Geländetypen |formações de relevo llaman a los accidentes geográficos... noem landvormen...

you have to take stuff from one place, move it, and put it somewhere else. ||||||||перемести|||||| tienes que coger cosas de un sitio, moverlas y ponerlas en otro. il faut prendre des choses à un endroit, les déplacer et les mettre ailleurs. é preciso tirar coisas de um sítio, movê-las e colocá-las noutro sítio.

Or technically speaking: erosion, transport, and deposition. ||||транспорт|| |||침식||| |||侵食|||堆積 O, en términos técnicos: erosión, transporte y deposición. Of technisch gesproken: erosie, transport en depositie.

The key to sand dunes is what's doing the moving, and what's getting moved. |||||||||||||перемещается La clave de las dunas de arena es lo que se mueve y lo que se mueve. La clé des dunes de sable est de savoir ce qui se déplace et ce qui est déplacé. 砂丘で重要なのは、移動するものと移動されるものだ。 A chave para as dunas de areia é o que está a mover-se e o que está a ser movido. Ключом к песчаным дюнам является то, что движется и что движется.

Sand is a paradox. It's solid. I mean, I'm sitting on it. But it can also flow like a |||||твердый|||||||||||течь|| |||모순||||||||||||||| La arena es una paradoja. Es sólida. Quiero decir, estoy sentado sobre ella. Pero también puede fluir como Zand is een paradox. Het is solide. Ik bedoel, ik zit erop. Maar het kan ook stromen als een A areia é um paradoxo. É sólida. Quero dizer, estou sentado nela. Mas também pode fluir como um

liquid. And sometimes, even behave a little bit like a gas. ||||ведет себя|||||| líquido. Y a veces, incluso se comportan un poco como un gas. Et parfois, il se comporte même un peu comme un gaz. líquido. E, por vezes, até se comportam um pouco como um gás.

Sand is weird stuff! And that weirdness is what causes it to form these patterns and ||странный||||странность||||||||узоры| ||||||奇妙さ||||||||| La arena es una cosa rara. Y esa rareza es lo que hace que forme estos patrones y Le sable est une matière étrange, et c'est cette bizarrerie qui lui permet de former ces motifs et ces formes. 砂は奇妙なものだ!むかついている砂のののの生長した。 A areia é uma coisa estranha! E essa estranheza é o que faz com que ela forme estes padrões e Песок - странная штука! И именно эта странность заставляет его формировать эти шаблоны и

shapes. формы

But, like… what IS it? Sand is just a special kind of dirt, right? WRONG. ||||||||||||земля|| ||||||||||||흙|| ||||||||||||terra|| Pero... ¿qué ES? La arena es sólo un tipo especial de suciedad, ¿verdad? ERROR. Но, типа... что ЭТО? Песок — это просто особый вид грязи, верно? НЕПРАВИЛЬНЫЙ.

Sand is so much more than that!  It's a record of millions of years of wind |||||||||запись|||||| |||||||||Aufzeichnung|||||| Zand is zoveel meer dan dat! Het is een record van miljoenen jaren wind A areia é muito mais do que isso! É um registo de milhões de anos de vento Песок — это нечто большее! Это запись миллионов лет ветра

and water that have carved their way across the surface of our planet: Mountains, rivers, |вода||||||||поверхности||||горы| ||||刻んだ|||||||||| ||||esculpido|||||||||| et de l'eau qui se sont frayés un chemin à la surface de notre planète : les montagnes, les rivières, en water dat zich een weg baant over het oppervlak van onze planeet: bergen, rivieren, e água que abriram caminho através da superfície do nosso planeta: Montanhas, rios,

and deserts long gone. |||ушедшие y desiertos desaparecidos hace tiempo. e desertos há muito desaparecidos. и пустыни давно нет.

It's… it's, you know… É... é, sabe...

that stuff.  The thing about sand is it isn't defined |||вещь||||||определено |stuff|||||||| esas cosas. Lo que pasa con la arena es que no está definida esse material. O problema da areia é que não está definida этот материал. Дело в том, что песок не определен

based on what it's made of. основанный||||| com base no material de que é feito. исходя из того, из чего он сделан.

It's defined based on the size of the particles. Anything between 1/16th of a mm and 2 mm? |||||размере||||всё||1/16|||мм|| ||||||||||||||Millimeter|| ||||||||입자|||||||| Se define en función del tamaño de las partículas. ¿Algo entre 1/16 de mm y 2 mm? Il est défini en fonction de la taille des particules : entre 1/16e de mm et 2 mm ? Het wordt gedefinieerd op basis van de grootte van de deeltjes. Iets tussen 1/16e van een mm en 2 mm? Он определяется на основе размера частиц. Что-нибудь между 1/16 мм и 2 мм?

That's technically sand. Isso é tecnicamente areia. Технически это песок.

The sand many of us are used to is tiny pieces of quartz that've been broken down from |||||||||||||которые|||| |||||||||||||が|||| ||||||||||||quartzo|||quebradas|| La arena a la que muchos de nosotros estamos acostumbrados son diminutos trozos de cuarzo que se han descompuesto de Het zand waar velen van ons aan gewend zijn, zijn kleine stukjes kwarts die zijn afgebroken A areia a que muitos de nós estamos habituados é constituída por pequenos pedaços de quartzo que foram decompostos a partir de Песок, к которому многие из нас привыкли, представляет собой крошечные кусочки кварца, расколотые из

bigger rocks.  But volcanic ash can be sand too. rocas más grandes. Pero la ceniza volcánica también puede ser arena. rochas maiores. Mas as cinzas vulcânicas também podem ser areia.

Or gypsum, like the famous White Sands of New Mexico. |Gips|||||||| |석고|||||||| |石膏||||ホワイト|||| |gypsum|||||||| Ou gesso, como as famosas Areias Brancas do Novo México. Или гипс, как знаменитые белые пески Нью-Мексико.

Some sand is really ground up coral or seashells. ||||gemahlen|||| ||||crushed or pulverized|||| |||||moído|||conchas Algunas arenas son en realidad coral molido o conchas marinas. Néhány homok valóban korall vagy tengeri kagyló.

Even the skeletons of plankton! ||骨|| Até os esqueletos de plâncton!

Small snow crystals can even technically be sand. |neve|||||| Les petits cristaux de neige peuvent même être techniquement du sable.

But maybe the strangest kind of sand on Earth comes from the beaches of Normandy, where |||most unusual|||||||||||| Mas talvez o tipo de areia mais estranho da Terra venha das praias da Normandia, onde

the D-Day invasions of WWII took place. They're covered in microscopic particles of shrapnel ||||||||||||||metal fragments ||||||||||||||estilhaços |||||Zweiter Weltkrieg|||||||||Splitterteilen ||||||||||||||파편 ||||||||||||||破片 ||||||||||||||esquirlas as invasões do Dia D da Segunda Guerra Mundial tiveram lugar. Estão cobertos de partículas microscópicas de estilhaços

known as “war sand”. ||guerra| conocida como "arena de guerra". conhecida como "areia de guerra".

So. What is sand? It's just really small stuff. Not like the very smallest stuff. But Então. O que é areia? É apenas uma coisa muito pequena. Não é o material mais pequeno. Mas

still really small. That pretty much covers it. még nagyon kicsi. Ez nagyjából lefedi. nog echt klein. Dat dekt het ongeveer. еще очень маленький. Это в значительной степени покрывает это.

And that Goldilocks size (not too big, not too small) lets sand move in a way that nothing ||Goldilocks-Größe||||||||||||||| ||Goldilocks size|||||||||||||||nothing ||Ricitos de Oro||||||||||||||| ||Papinha|||||||||||||maneira||nada Et cette taille "Boucles d'or" (ni trop grande, ni trop petite) permet au sable de se déplacer d'une manière que rien ne permet d'espérer. И этот размер Златовласки (не слишком большой и не слишком маленький) позволяет песку двигаться так, что ничто

else really does. еще действительно делает.

Big stuff, like rocks… wind doesn't do much to them. Крупные предметы, такие как камни… ветер мало что с ними делает.

Slightly smaller stuff like gravel, if enough wind hits it, might do this. ||||Kies|||||||| ||||砂利|||||||| ligeiramente|||||||||||| Des éléments un peu plus petits comme le gravier, s'ils sont frappés par un vent suffisant, peuvent le faire. Iets kleinere dingen zoals grind, als er voldoende wind op komt, zou dit kunnen doen. Немного более мелкий материал, такой как гравий, может сделать это, если на него ударит сильный ветер.

The very smallest stuff, like dust, gets swept into the wind and stays there. |||||||날아간다|||||| |mesmo|menor|||poeira||varrido|||||| De allerkleinste dingen, zoals stof, worden meegesleurd in de wind en blijven daar. Самые мелкие частицы, такие как пыль, уносятся ветром и остаются там.

Sometimes traveling thousands of miles before it lands again.

Sand is just small enough to be lifted and swept along by the wind, but big enough that |||||||||fortgeweht|||||||| ||apenas|||||levado|||junto||||||| Песок достаточно мал, чтобы его поднимал и уносил ветер, но достаточно велик, чтобы

it doesn't stay up for long. ||permanece|para cima||muito это не остается на долго. 它不会持续很长时间。

This bouncing is what happens as sand is blown by wind across arid desert-like surfaces, |hüpfende|||||||||||trockenen||| ||||||||||||dry||| ||||||||吹かれる||||乾燥した||| Isso|quicando|||||||||||||| Ce rebondissement se produit lorsque le sable est soufflé par le vent sur des surfaces arides et désertiques, Это подпрыгивание происходит, когда песок разносится ветром по засушливым пустынным поверхностям.

though it's difficult to see with the naked eye. embora|||||||a olho nu| хотя это трудно увидеть невооруженным глазом.

Sit down near a sandy surface on a windy day, though, and you'll definitely feel it

If you've ever looked at any sand-covered surface that's been shaped by wind, you've

probably noticed these evenly spaced, repeating ridges or ripples of sand, usually a few centimeters |||uniformly||||||||||| вероятно, заметил эти равномерно расположенные повторяющиеся гребни или рябь песка, обычно в несколько сантиметров

apart. Кроме.

And these are another paradox. How does this turbulent cloud of bouncing, chaotic sand ||||逆説||||||||| そして、これらはもうひとつのパラドックスである。この乱れ飛ぶ砂の雲は、どのようにして En dit is een andere paradox. Hoe werkt deze turbulente wolk van stuiterend, chaotisch zand?

create… order?  I think by far the coolest thing about the |pedido||||||||| создать… порядок? Я думаю, что самая крутая вещь в

dunes, it isn't the dunes themselves, it's these patterns that form on the surface of ||||||||Muster|||||| |||||elas mesmas||||||||| дюны, это не сами дюны, это узоры, которые образуются на поверхности

the sand.

you'd think if the wind were blowing across this sand, you'd just end up with a nice вы думаете, если бы ветер дул по этому песку, вы бы просто закончили с хорошим 你会想,如果风吹过这片沙子,你最终会得到一个漂亮的结果

smooth surface, it'd just even everything out. But that's not what happens. lisa||||||||||| superficie lisa, que acaba de igualar todo. Pero eso no es lo que ocurre. Mais ce n'est pas ce qui se passe. glad oppervlak, het zou gewoon alles eruit halen. Maar dat is niet wat er gebeurt. гладкая поверхность, это просто выровняло бы все. Но это не то, что происходит.

These beautiful ripples, they're almost like “fingerprints” of the sand dune. ||ondulações|||||||| Эта красивая рябь, она почти как «отпечатки пальцев» песчаной дюны.

I mean, it looks like someone came out here with a rake and made these. But what is so |||||||||||Rechen||||||| |||||||||||garden tool||||||| |||||||||||rastrillo||||||| ||||||veio|||||ancinho||||||| Ik bedoel, het lijkt erop dat iemand hier met een hark kwam en deze maakte. Maar wat is zo? Я имею в виду, похоже, что кто-то пришел сюда с граблями и сделал это. Но что так

amazing about these ripples, is they form themselves. They organize themselves, out verbazingwekkend aan deze rimpelingen, is dat ze zichzelf vormen. Ze organiseren zichzelf, uit Удивительно в этих рябях то, что они формируются сами собой. Они организуют себя, вне

of just wind and sand. только ветер и песок.

So how do these ridges form? ||||Rücken| Так как же образуются эти гребни?

Well once a grain of sand is lifted into the wind and dragged along, when it hits the sand Welnu, als een zandkorrel eenmaal in de wind wordt getild en meegesleurd, wanneer hij het zand raakt Хорошо, когда песчинку поднимает ветер и тащит за собой, когда она ударяется о песок

surface again, it almost splashes, driving more grains of sand up into the wind. ||||spritzt||||||||| ||||はじける|||粒|||||| поверхность снова, он почти разбрызгивается, поднимая по ветру новые песчинки.

But the distance of those hops isn't random. It depends on how big and heavy the grains |||||跳躍||||||||||| |||||saltos||||||||||| Maar de afstand van die sprongen is niet willekeurig. Het hangt af van hoe groot en zwaar de korrels zijn Але відстань між цими хмелями не випадкова. Це залежить від того, наскільки великі та важкі зерна

are and how fast the wind is moving. And this is likely the key to why these ripples form. ||||||||||||||理由|||| и как быстро дует ветер. И это, вероятно, ключ к тому, почему образуются эти волны.

So this feedback loop of bouncing sand begins to form on the surface. All it takes is a ||feedback loop|loop|||||||||||||| Así que este bucle de retroalimentación de arena que rebota comienza a formarse en la superficie. Todo lo que se necesita es un 砂の跳ね返りのフィードバックループが表面に形成され始めるのだ。必要なのは Dus deze feedbacklus van stuiterend zand begint zich op het oppervlak te vormen. Het enige dat nodig is, is een Таким образом, на поверхности начинает формироваться эта петля обратной связи прыгающего песка. Все, что нужно, это

little random spot where a few more grains of sand land than others. And that creates un pequeño punto al azar donde caen unos granos de arena más que otros. Y eso crea 砂の粒が他より少し多く着地するような、ちょっとしたランダムな場所だ。それが маленькое случайное место, где приземляется на несколько песчинок больше, чем других. И это создает

a little hump, which causes even more sand to land there. And a little shadow behind ||Höcker||||||||||||Schatten| ||bump||||||||||||| ||小さな隆起||||||||||||| ||montículo||||||||||||| ||uma pequena elevação||||||||||||| 小さなこぶがあり、そこにさらに砂が降り積もる。そして、その背後には小さな影が een bult, waardoor er nog meer zand op de grond komt. En een beetje schaduw achter небольшой горб, из-за которого туда оседает еще больше песка. И маленькая тень позади

that hump where less sand is landing. 砂の着地が少ないあのコブだ。 тот горб, где меньше песка приземляется.

That pattern repeats itself all the way down the row. Again, just based on the size of |patrón||||||||||||||| |padrão||||||||fileira||||||| Ese patrón se repite a lo largo de toda la fila. Una vez más, sólo basado en el tamaño de このパターンが列の下までずっと繰り返される。繰り返しますが Этот шаблон повторяется на всем протяжении строки. Опять же, только исходя из размера

the grains of sand and how far they bounce in that wind. los granos de arena y lo lejos que rebotan con el viento. 砂粒が風に乗ってどこまで跳ねるか。 песчинки и как далеко они отскакивают от ветра.

Bouncing sand, pulled along by the wind… self organizes to make this. ||||||||自己組織化||| |||junto|||||||| Arena que rebota, arrastrada por el viento... uno mismo se organiza para hacer esto. 砂が跳ね、風に引っ張られ......。 Прыгающий песок, увлекаемый ветром… самоорганизуется, чтобы сделать это.

The size and distance between these ripples can be different in different conditions: これらの波紋の大きさや間隔は、コンディションによって異なる:

different wind, different sized sand = different ripples. разный ветер, разный размер песка = разная рябь.

And if we speed up time, we can even watch those ripples move. |||velocidade|acelerarmos|tempo||||||| そして、時間を早めれば、その波紋の動きを見ることもできる。

Much of what is known about how sand and wind interact to form dunes is thanks to this man: ||||||||||interagieren|||||||| 砂と風がどのように相互作用して砂丘を形成するかについて知られていることの多くは、この人物のおかげである: Многое из того, что известно о взаимодействии песка и ветра при формировании дюн, получено благодаря этому человеку:

Ralph Bagnold. An explorer and brigadier in the British army, he was stationed in North |Bagnold||||||||||||| Ralph|Bagnold||||||||||||| |バグノルド||||准将||||||||| ラルフ・バグノルド探検家であり、イギリス陸軍准将であったバニョルドは、北マリアナ諸島に駐屯していた。

Africa between WWI and WWII. ||Erster Weltkrieg|| ||第一次世界大戦||

In 1929 he completed an expedition in search of a mythical oasis city called Zerzura, crossing |||||||||mythologischen||||Zerzura| |||||||||||||oasis city| |||||||||||||ゼルズーラ| В 1929 году он завершил экспедицию в поисках мифического города-оазиса Зерзура, пересекая 1929 年,他完成了一次寻找神话般的绿洲城市 Zerzura 的探险,穿越

the sand seas of the Libyan desert in a caravan of Ford Model A cars. |||||||||||Ford Model A||| по песчаным морям Ливийской пустыни в караване автомобилей Ford Model A. 乘坐福特 A 型汽车的大篷车穿越利比亚沙漠的沙海。

His partner on that expedition was a Hungarian adventurer named László Almásy, who was ||||||||||László Almásy|Almásy|| ||||||||||László|Almásy|| ||||||||||ラースロー|アルマーシ|| その探検のパートナーは、ラースロー・アルマシーというハンガリー人の冒険家だった。 Его партнером в этой экспедиции был венгерский авантюрист Ласло Алмаши, который был

later made famous in the film The English Patient, where he was played by Voldemort. ||||||||||||||Voldemort ||||||||||||||Ralph Fiennes ||||||||paciente|||||| más tarde se hizo famoso en la película El paciente inglés, donde fue interpretado por Voldemort. 後に映画『イングリッシュ・ペイシェント』でヴォルデモートに扮したことで有名になった。 Позже он прославился в фильме "Английский пациент", где его сыграл Вольдеморт.

Bagnold never found that mythical oasis, but he did discover the foundations of Aeolian |||||||||||||äolischen |||||||||||||エオリアン |||||||||||||aeólica Bagnold nunca encontró ese mítico oasis, pero sí descubrió los cimientos de Eolia バニョルドは神話上のオアシスを発見することはなかったが、エオリア諸島の基礎を発見した。 Багнольд так и не нашел этот мифический оазис, но он обнаружил фундамент Эолийского

processes, that's the technical term for how wind shapes land through moving sand and Процессы - это технический термин, обозначающий, как ветер формирует землю, перемещая песок и

sediment, named for the Greek god of the wind. ||||grego|||| ギリシャ神話の風の神にちなんで名付けられたセディメント。 sediment, genoemd naar de Griekse god van de wind. Осадок, названный в честь греческого бога ветра.

And his 1941 book is still used today. It's a bit dry, Y su libro de 1941 se sigue utilizando hoy en día. Es un poco seco, そして、彼の1941年の著書は今日でも使われている。ちょっと辛口だけどね、

but what do you expect for a book about sand? でも、砂の本に何を期待しているんだ?

Thank you, thank you.

It's pretty awesome that in a system that seems like random noise—bouncing sand, it's ||||||||parece||aleatório|ruído||| Es ist ziemlich genial, dass in einem System, das wie zufällig aufgewirbelter Sand aussieht, es Es bastante asombroso que en un sistema que parece arena que rebota ruido al azar, sea このシステムは、ランダムなノイズを跳ね返す砂のように見えるが、これはかなりすごいことだ。 Потрясающе, что в системе, которая кажется случайным песком с шумом, есть

like the physical version of TV static—even there, patterns do, in fact, exist. como la versión física de la estática televisiva: incluso en este caso, los patrones existen. テレビの静止画の物理的バージョンのようなもので、そこでもパターンは実際に存在する。 как физическая версия телевизионной статики - даже там паттерны действительно существуют.

Creating order on small scales… 小さなスケールで秩序を生み出す... Orde scheppen op kleine schaal… Создание порядка в небольших масштабах...

and large

Sand dunes can range from a few meters high to towering, sculpted mountains hundreds of ||||||||||altas|||| ||||||||||imponentes|||| 砂丘の高さは数メートルのものから、何百メートルもそびえ立つ彫刻のような山まである。 Высота песчаных дюн может варьироваться от нескольких метров до возвышающихся, скульптурных гор в сотни

meters tall. Like these at Great Sand Dunes National Park in Colorado, where I decided |||||||Dünen||||||| メートルの高さだ。コロラド州のグレートサンドデューンズ国立公園で私が決めたように。 Такие, как в Национальном парке Грейт-Сэнд-Дюнс в Колорадо, где я решил

to climb them.

Like ripples, dunes are also formed by the interaction of wind and moving particles… |Wellen|||||||||||| ||dunes||||||||||| 砂丘もさざ波と同様、風と移動する粒子の相互作用によって形成される。 Подобно ряби, дюны также образуются в результате взаимодействия ветра и движущихся частиц...

But sand dunes happen for a completely different reason. It's not just sand colliding with |||||||||||||衝突する| |||||||||||||colidindo| しかし、砂丘ができる理由はまったく違う。単に砂が Но песчаные дюны возникают совсем по другой причине. Это не просто столкновение песка с

other sand, this is aerodynamics. これが空気力学だ。 ander zand, dit is aerodynamica.

When wind flows over an obstacle, like a large bump of sand, it speeds up. Cuando el viento pasa por encima de un obstáculo, como un gran bulto de arena, se acelera. 風が大きな砂の段差のような障害物の上を流れるとき、風速は速くなる。 Wanneer wind over een obstakel stroomt, als een grote zandbult, versnelt het. Когда ветер обтекает препятствие, например большую песчаную кочку, он ускоряется.

This is why winds are often much stronger on top of hills… |||||||||||colinas 丘の上の方が風が強いのはそのためだ。

Dunes form when wind accelerates over an obstacle, eroding sand as it goes. What's weird is |||||||||||||||is ||||||||砂を削る||||||| 砂丘は、風が障害物を越えて加速し、砂を侵食することで形成される。奇妙なのは Дюны образуются, когда ветер налетает на препятствие, размывая песок по ходу движения. Что странно, так это то, что

the spot on the hill where the wind is pulling hardest on the sand, where the most erosion |o local|||||||||||||||| 丘の上で風が最も強く砂を引っ張る場所、最も浸食が激しい場所。 место на холме, где ветер сильнее всего натягивает песок, где больше всего эрозии.

occurs, it isn't here at the top, which is what you might expect. The most erosion Но, как и следовало ожидать, он находится не на самом верху. Самый эрозионный

happens here on the windy side of the dune. Those grains bounce up the hill, pulled by ocurre aquí, en el lado ventoso de la duna. Esos granos rebotan colina arriba, arrastrados por この砂丘の風の強い側で起こる。砂粒が丘の上に跳ね上がり、それに引っ張られる。 Это происходит здесь, на подветренной стороне дюны. Зерна подпрыгивают вверх по склону, подгоняемые

the wind, and get dumped at the crest of the growing pile. So the dune can grow. |||||||top||||||||| |||||||頂上||||||||| ||||depositado|||crista||||da pilha||||| den Wind und werden am Kamm des wachsenden Haufens abgeladen. So kann die Düne wachsen. el viento, y se vierten en la cresta de la creciente pila. Así la duna puede crecer. 砂丘は風によって削られ、成長する砂丘の頂上に捨てられる。だから砂丘は成長できる。 de wind, en wordt gedumpt op de top van de groeiende stapel. Het duin kan dus groeien. и сбрасываются на гребень растущей кучи. Таким образом, дюна может расти.

Because the sand gets eroded the most here, and not at the top, that's the reason dunes ||||侵食される|||||||||||| Omdat het zand hier het meest geërodeerd wordt, en niet aan de top, zijn dat de duinen Потому что песок размывается больше всего здесь, а не на вершине, вот почему дюны

exist instead of getting blown away by the wind.

So as the wind comes up the front side of the dune, eroding sand, it deposits it here だから、風が砂丘の前側を上がってきて砂を浸食し、ここに堆積させる。 Так что, когда ветер поднимается по передней стороне дюны, размывая песок, он откладывает его здесь.

at the crest. Then something weird happens. You can't stack sand forever. Once the angle на гребне. И тут происходит нечто странное. Вы не можете складывать песок вечно. Как только угол

of that stack gets to be 33 or 34 degrees, you get an avalanche. You can try it yourself |||||||||||Lawine||||| |||||||||||雪崩||||| В стоге достигнет 33 или 34 градусов, произойдет сход лавины. Вы можете попробовать сами.

at home.

Look at this finely powdered sugar. It's almost like dust. Because all those small Посмотрите на эту тонкую сахарную пудру. Она почти как пыль. Потому что все эти маленькие

particles can pack in with each other and be nice and comfy, it can be stacked to super-steep |||||||||||cómoda|||||||superempinado partículas se pueden empaquetar entre sí y ser agradable y cómodo, se puede apilar a super-empinada частицы могут складываться друг в друга и быть удобными, их можно укладывать на супер-высокие

angles without avalanching. Nearly vertical even! ||雪崩||| hoeken zonder lawine. Bijna verticaal zelfs! Углы без обвала. Даже почти вертикальные!

But larger granular materials, like this table sugar, which in this demonstration represents Но более крупные гранулированные материалы, такие как столовый сахар, который в данной демонстрации представляет собой

sand, they avalanche at a much shalloEwer angle, because they can't pack as tightly. ||||||flacheren||||||| ||||||shallower||||||| ||||||浅い||||||| Sand, so dass sie in einem viel flacheren Winkel abrutschen, weil sie nicht so dicht gepackt werden können. 砂の場合、詰めが甘いため、雪崩の角度が浅くなる。 zand, lawineseren ze in een veel ondiepere hoek, omdat ze niet zo strak kunnen samenpakken. песка, они лавируют под гораздо меньшим углом, потому что не могут так плотно упаковываться.

And you can see that right behind me. This line is the palace where avalanche after avalanche ||||||||||||Palast|||| Y se puede ver que justo detrás de mí. Esta línea es el palacio donde avalancha tras avalancha 私の真後ろにも見えるだろう。このラインは、雪崩に次ぐ雪崩が起きた宮殿だ。 Вы можете видеть это прямо за мной. Эта линия - дворец, где сходит лавина за лавиной.

have occurred, shaping this side of the dune. が発生し、砂丘のこちら側を形成した。 hebben plaatsgevonden, die deze kant van het duin hebben gevormd.

Anybody have a protractor? Anybody? Should have brought one. Measure it. |||Geodreieck||||||| |||protractor||||||| |||分度器||||||| ¿Alguien tiene un transportador? ¿Alguien? Debería haber traído uno. Mídelo. 分度器を持っている人は?誰か?持ってくるべきだった。測ってくれ

Some really interesting things happen right at the top too. The air passing over the dune Auch auf dem Gipfel passieren einige wirklich interessante Dinge. Die Luft, die über die Düne strömt Er gebeuren ook echt interessante dingen aan de top. De lucht die over het duin gaat

will try to follow the curve of the dune. wird versuchen, der Kurve der Düne zu folgen. は砂丘のカーブに沿おうとする。

The same way that liquid will flow down the side of a cup if it's poured too shallow. |||||||||||||||||too shallow |||||||||||||||vertido|| 浅く注ぐと液体がコップの側面に流れ落ちるのと同じことだ。

But if the flow is faster, and the surface peels away really sharply, like it does thanks ||||||||||||||||thanks to |||||||||剥がれる||||||| Aber wenn die Strömung schneller ist und sich die Oberfläche sehr stark ablöst, wie es beim Dank der Fall ist Pero si el flujo es más rápido, y la superficie se despega muy bruscamente, como lo hace gracias しかし、もし流れが速くなり、表面が鋭く剥離するようなことがあれば、それは感謝すべきことだ。

to that avalanche angle, the air detaches and can't follow, just like how water poured ||||||剥がれる|||||||| a ese ángulo de avalancha, el aire se desprende y no puede seguir, igual que cuando el agua se vierte

from a spout pours into our cup and doesn't flow down the side. ||Ausguss|||||||||| aus einer Tülle in unsere Tasse fließt und nicht an der Seite herunterläuft. de un caño se vierte en nuestra taza y no fluye por el lateral.

The wind is clearly blowing sand off the top of the dune, but as long as the wind from

upstream keeps depositing more sand at the top than gets blown away, the dune won't ||堆積する|||||||||||| Si la corriente ascendente sigue depositando más arena en la cima de la que se lleva el viento, la duna no se desintegrará.

shrink.

As sand piles and avalanches, the whole dune may even move or migrate, ||||雪崩||||||||移動する

over months or years.

Dunes can grow to ridiculously large scales. The ones I climbed were more than 700 feet Duinen kunnen uitgroeien tot belachelijk grote schalen. Degenen die ik beklom waren meer dan 700 voet

above where I started.

Many dunes are even visible from space! And from that perspective I think you get the

clearest view that there's obviously another level of order arising from the chaos and duidelijkste zicht dat er duidelijk een ander niveau van orde voortkomt uit de chaos en

turbulence of sand blowing in the wind.

And that order comes in many different shapes. The shape of a dune tells us about the wind En die volgorde komt in veel verschillende vormen. De vorm van een duin vertelt ons over de wind

that created it. This is a transverse dune. A barchan dune. A longitudinal dune. And a ||||||quer|||Barchan-Düne|||||| ||||||crosswise|||barchan dune|||linear dune||| ||||||横断的な|||バルカン|||||| |||||||||barchán|||||| dat het heeft gemaakt. Dit is een dwarsduin. Een Barchan-duin. Een langsduin. En een

star dune. Just a few of the shapes that dunes can take. Sterndüne. Dies sind nur einige der Formen, die Dünen annehmen können.

Why Care? Let's be real for a sec. Some of you are |||||||eine Sekunde|||| ¿Por qué preocuparse? Seamos realistas un momento. Algunos de ustedes son

probably saying, “hey Joe, why should I care about wind blowing a bunch of sand around?” Wahrscheinlich sagt er: "Hey Joe, warum sollte ich mich darum kümmern, dass der Wind einen Haufen Sand umherweht?"

And to that I say “Knowing stuff is awesome.” Und dazu sage ich: "Wissen ist großartig".

And also because moving sand impacts a lot of people's lives. Und auch, weil das Bewegen von Sand das Leben vieler Menschen beeinträchtigt.

As temperatures rise on Earth and our population expands, urbanization, mining, farming, and

deforestation are degrading lands into dry, desert-like landscapes. It's called “desertification”, |||||||||||Wüstenbildung |||||||||||land degradation 森林伐採||劣化させている|||||||||砂漠化 ontbossing degradeert land tot droge, woestijnachtige landschappen. Het heet "woestijnvorming",

and every year, an area equal to half the European Union deteriorates into dusty, scorched ||||||||||||||quemada und jedes Jahr verkommt eine Fläche, die der Hälfte der Europäischen Union entspricht, zu staubigen, verbrannten y cada año, una superficie equivalente a la mitad de la Unión Europea se deteriora en polvorientos y abrasados

Earth. Climate change will only speed that up.

30% of Earth's surface could end up drying out, affecting billions of people. 30% van het aardoppervlak zou kunnen uitdrogen, met gevolgen voor miljarden mensen.

And as erosion increases, dunes may threaten to bury whole towns. Y a medida que aumenta la erosión, las dunas pueden amenazar con sepultar ciudades enteras.

Towns like the tiny spaceport of Mos Espa, in Tunisia, slowly getting swallowed by a ||||Raumhafen||Mos Espa|Mos Espa||||||| ||||||Espa|Mos Espa||||||| ||||宇宙港||モス|モス・エスパ||チュニジア||||| ||||puerto espacial||||||||||

giant moving sand dune.

Ok, that's actually the set they built for Star Wars: Episode I, but it'll happen to ||||||||||Episode I||||| Vale, en realidad es el decorado que construyeron para Star Wars: Episodio I, pero pasará a

real places too! In fact, it was the threat of sand dunes overtaking ||||||||||||侵食する ¡lugares reales también! De hecho, fue la amenaza de las dunas de arena la que superó ook echte plaatsen! In feite was het de dreiging van het inhalen van zandduinen

a coastal town in Oregon that inspired one of the greatest works of science fiction ever

written.

A young newspaper reporter was sent to investigate how engineers and ecologists were fighting |||||||||||生態学者||

to keep migrating dunes from swallowing roads, bridges, and houses.

The story he was sent to write was never written, but a few years later, he wrote a book you

may have heard of: Dune. Watch out for sandworms, kids! Never know ||||Dune (1)||||||| ||||||||砂虫|||

when you're gonna run into one of those things. cuando te vas a encontrar con una de esas cosas. wanneer je een van die dingen tegenkomt.

In that story, the complex interplay of life and sand on the desert world Arrakis is threatened ||||||||||||||Arrakis|| |||||相互作用|||||||||アラキス|| ||||||||||||||Arrakis||

with collapse at the hands of humans. con el colapso a manos de los humanos.

It's a lesson about appreciating the delicate balance and the forces of nature. A warning ||||||empfindliches||||||||

about our own planet. But also a hint that what happens here on Earth, happens elsewhere. |||||||indicio||||||||

You see, our planet isn't the only planet with dunes.

We find sand dunes on Mars, with unique ripples and hills shaped by the thin atmosphere and

constant winds of the red planet. Dunes on Saturn's moon Titan, made of frozen hydrocarbons. ||||||||土星の||タイタン||||炭化水素 constante wind van de rode planeet. Duinen op Saturnusmaan Titan, gemaakt van bevroren koolwaterstoffen.

Even dunes of frozen methane on Pluto. It's pretty likely that every solid thing ||||||冥王星|||||||

in our solar system or others has some fine-grained stuff on its surface, something sand like. |||||||||細かい粒状の||||||| in ons zonnestelsel of anderen heeft wat fijnkorrelig spul op het oppervlak, iets zandachtigs.

So wherever there's an atmosphere that can move that grainy stuff, patterns like ripples |||||||||粒状の||||

and dunes will also form there. These patterns are fingerprints left by a planet's past, y también se formarán dunas. Estos patrones son huellas dactilares dejadas por el pasado de un planeta,

ours and others.

So why care about big piles of sand?

Well, because they are beautiful. Because it feels good to understand why something

is the way it is, not just how it is. And because they are an incredible example of

self-organization and patterns formed by physics alone. But also because something as simple

as wind and sand can inspire us to think about something a bit bigger.

I think I finally understand what the poet WIlliam Blake meant when he wrote: ||||||||William Blake|Blake|||| ||||||||William|William Blake|||| Здається, я нарешті зрозумів, що мав на увазі поет Вільям Блейк, коли писав:

To see the world in a grain of sand, and heaven in a wildflower, |||||||||||||Wildblume |||||||||||||flower |||||||||||||野の花 Бачити світ у піщинці, а небо - у польовій квітці,

hold infinity in the palm of your hand, and eternity |無限||||||||

in an hour.

Stay curious.