[SINGING]
You know.
You can sing it yourself.
And then, you don't get dinged on copyright, maybe.
Game of Thrones is incredible.
It's amazing.
I love all the characters and the intrigue and the plot
twists and how no single story or person is too precious
and could just be killed at any time.
I actually really like that.
My first episode that I ever watched,
it was at the end of season one, I remember, because I walked in
and my roommates were watching it on the TV.
And I was like, what the heck is this?
And they were like, oh.
OK.
You can't watch now, because-- and I was like, I get it.
Dragon lady.
She's important.
I don't know.
Whatever.
Just let me watch.
I was hooked, immediately.
Next thing you know, I watched all the episodes,
read all the books, read the nerdy blogs.
I even got the supplemental book about the history
of Game of Thrones and the Seven Kingdoms from the library
recently.
And actually I'm sort of just realizing now
that I did a whole talk about how Dothraki
could be a real language.
Yeah it was wow.
[DOTHRAKI]
But aside from the dragons, the magic white trees,
the slipping into other people's bodies,
and the super cold zombies, there's
always been this one thing that just, you know, bothered me
about the security concerns of the Seven Kingdoms
and that is the wall.
These humans seem to be great at building
castles and ships and swords and potions and stuff.
This isn't just any old wall we're talking.
About it's 213 meters tall, 500 kilometers long.
It's 91 meters thick.
It's like a skyscraper that is as long as the Grand Canyon.
So we veered strongly into fantasy with the wall,
from page one.
Actually, the wall didn't appear til page 19.
Page 19.
Got it.
Anyway, I wanted to know the feasibility
of this giant wall of ice.
Could we build this?
I can crush ice between my teeth.
So can ice actually hold that kind of weight?
I found some experts who know a bit about glaciers and ice
sculptures and construction.
And I put them all together for this episode of Hello Science.
So let's see if we can take this amazing architecture out
of fantasy and bring it into some facts.
Shall we?
Welcome people of the north and all of the Seven Kingdoms.
Have some bread and salt and share my table.
"To the north loomed the wall, almost 700 feet high
it stood, three times the height of the tallest tower
in the stronghold it sheltered.
His uncle said the top was wide enough for a dozen
armored knights to ride abreast."
The wall is massive.
And its whole job is to keep the Night King out of Wester--
what was that spoiler?
It's been two years.
Come on.
I guess it just, you know, didn't work.
But regardless of what actually happened to the wall
or will happen to the wall, building giant things like that
is entrancing, right?
So if I remember correctly from geometry
plus my 2006 tour of Egypt, what we need
is a slope, a bunch of giant bricks,
and a large supply of cheap labor.
But before we can construct, really,
anything, anywhere, at any time in history,
even the great pyramids, what we really need
is an engineer to make a plan.
I think there are two main stages to construction.
There's the preconstruction part where all of the drawings
need to be created.
And so engineers have to take into consideration
where the building is going to be built, what it's built upon,
what conditions it's going to encounter while it's there,
and take into consideration all of those things,
so they can come up with the design.
So really, thinking through everything
that is going to impact the structure over time.
My name is Mara Tsudis.
I am an engineer and project manager.
And my favorite Game of Thrones character is Missandei.
She came from nothing.
She proved her own way.
She's gorgeous.
I love her outfits.
She's top notch.
She's my favorite.
So for perspective, this is what we're going to build.
It's the wall.
It's about the same height as San Francisco's Golden Gate
Bridge and as wide as three of them.
Whoa.
I know.
I asked Mara what it would take to build something as massive
as a 213-meter tall wall.
Once you have the design and everything is finalized,
then comes the idea of how are we actually going to do this.
Are you going to go from right to left or start in the middle?
And why would you need to do something different?
If you think ancient Egypt, how were they
building things that tall?
They needed that pyramid shape to move
the material to the top.
They're going to have to move that material manually up
to the top of the wall.
Now, we can use a crane.
And we can take a crane and move material to the top.
But if you're talking Game of Thrones time,
they're going to have to create some kind of pyramid
shape, at least some kind of slope, to move the material up.
Even when I have construction drawings that
are 100% approved, I go in and I have
to test for compaction in soil and other existing conditions.
And so that can change everything
that they design for, if what we actually have is different.
You have all of these people who have looked at drawings,
who have thought of things.
And then, we get there and we say, wait,
we can't open this door, because this is there.
The wall is big.
It's heavy.
And like any building, it has to sit on the surface of the Earth
in some way that is safe.
You wouldn't want to build the wall
and have it sink into the soil and fall over due to high winds
or anything like that.
We're not even going to consider the fact
that catapulting rocks from the top of the wall
would put a huge amount of shearing stress on the wall
thanks to Newton's laws.
But think about the physical structure itself instead.
Like what is underneath the wall?
Ice?
On the coasts, there's definitely a beach.
So is it sand?
What's under the sand and what's under the ice?
I mean, maybe the sand has a really good bedrock
or foundation underneath it you can drill into.
And maybe the ice is ice for a really long time
and there's nothing solid or maybe it moves more.
I don't know.
This is a fictional world.
We don't know what we're getting.
They could have different laws of physics.
We don't know.
There is magic.
As a general rule, the taller the building is,
the deeper its foundation must be.
The mass of the wall would definitely
require some ridiculous foundations.
In the early years of skyscraper construction,
engineers realized that they needed
to dig foundations of these big heavy buildings
deeper than topsoil to keep the building
from falling over or sinking.
So what they did is they learned to sink
what are called piles into the ground below the foundation.
Piles are wood or cement or steel poles, essentially.
If they couldn't do that, they just
had to keep digging until they got to bedrock, because that's
stable.
For something like the Empire State Building,
for example, there are 210 piles driven more than a dozen meters
into the rock and soil of the island of Manhattan.
And that's what keeps the building upright and stable.
And Bran the Builder would also have
to consider the mass of the wall.
Skyscrapers aren't solid.
They're hollow, just a skin of glass of brick
over a steel skeleton.
The square-cube law says, generally speaking,
the volume of a thing grows much faster than its surface area.
And so to build the wall, you'd have to move a lot of material,
like eight swimming pools of water, ice,
for every meter of wall constructed.
The logistics of getting so much material into one place
exhausts me to think about it.
Ice is so heavy that you can't pile too much on a small base
or it will fracture or break with the increased weight.
A cubic meter of ice is actually 2,026 pounds.
And this would be a factor with building an enormous wall.
That means 1 meter wide, 213-meter tall section
of the wall would weigh 17.8 million kilograms.
That's Rex by the way.
He is my version of Bran the Builder
Hi.
I'm Rex Covington.
And I'm a sculptor here in Los Angeles.
You know, I don't watch Game of Thrones religiously.
But I've seen many episodes.
And I've definitely seen the ice wall
and some of the good episodes with the dragons and stuff.
Rex knows ice.
He's been working with it for decades.
He knows how to make it, to build with it, to chop it up,
and to turn it into everything from, say,
a rearing horse or an eight foot tall person to an entire ice
wall complete with fully stocked.
Bar he's my kind of guy.
If there's any degree of radius or curvature to the wall,
then it would certainly stand without question
and be less likely to fall over.
So if it were 300 miles long and there was some curvature to it,
likely, it would stand.
You need a large enough footprint
to support the weight.
Just talking about real life, not with magic.
But magic could help.
If the base is big enough, it really
could support an unbelievably large amount of weight,
like a glacier.
That's right.
Think of the wall not as a skyscraper,
says Rex, but as a glacier, a 500 km long 200 meter
high mass of ice cutting through the landscape of the north
and ending in the sea, on both ends.
Those dimensions remind me a little bit
of the Jakobshavn Glacier, which is a glacier in Greenland.
And it's where the iceberg fell off, that they think,
sunk the Titanic.
That's Mary Miller.
I figured, since we're talking glaciers,
why not bring in someone who has seen her fair share?
I'm Mary Miller.
I'm the director of environmental science
here at the Exploratorium.
My favorite thing about Game of Thrones
is the dragons, of course.
But my mother-in-law is a huge fan.
So she is going to so super excited that on a video
about Game of Thrones.
In order to actually build something
that's like the Wall of Ice, it would take a lot of work.
I mean, nature builds walls of ice.
They're called glaciers.
Mary also has experience building
her own walls of ice while on research trips in Antarctica.
Building a small wall was a lot of work.
It took about five of us three or four hours
to cut chunks of ice out of the snow and then just build a wall
and pitch our tent on the other side of it.
But some people actually really got into it
and they built igloos and snow caves
and just loved playing around with the snow.
But I was exhausted.
Glaciers are like nature's versions of the wall.
But they're built over thousands upon thousands of years.
A glacier uses falling snow to build on the top.
And then, the weight compresses the snow below it.
And that eventually makes ice.
I'll let Mary explain it.
If you cross section that glacier from the top
to the bottom, the top would be sort of more fluffy white snow.
As you get farther down, the compaction of the snow
forces most of the air out, or into really small bubbles.
And then, you see a much more sort of clear or blue color
with little bubbles in it, all the way
to the bottom where you might see a film with water
on the bottom.
And that water is important, because though glaciers
do seem solid to us, on human scales,
they're actually not at all.
I think people look at these big ice sheets and glaciers
as being extremely stable, but they're very dynamic.
Anything that big and massive wants to spread out.
A famous glaciologist, Richard Alley,
told me that glaciers are like pancakes.
When you pour pancake batter on a griddle,
it wants to spread out under its own weight.
And if you pour enough of it, it will fall off
the edge of your griddle, which is what happens
when glaciers calve off.
And you probably have seen these big icebergs
falling off glaciers in Greenland and Antarctica.
That's what happens, is that the glacier is moving.
It reaches the edge and gravity just takes it off the edge.
So it would seem, we'll never be able to actually build
something like this out of ice, at least using
traditional building materials.
Even though it might be strong enough to hold up its own mass,
the soil might not be stable enough,
we'd need a surveyor to find out.
And on Earth, ice melts under pressure,
which is part of the reason glaciers
flow across the landscape and the wall would likely
bow out at the bottom.
So let's instead just assume that we
had the perfect conditions and the magic
is what's helping hold it up.
So according to our experts, this
is what we would need to build the wall.
So when we built our survival wall, our ice
wall in Antarctica, we just dug the ice blocks out
of snow that was there that had compacted over time.
I imagine that you probably could make a mold
and pour water into it.
What if you made forms like you do with concrete?
But instead of pumping up concrete you pump up water.
It would probably be really clear ice
if you had to pump up like boiling water.
Cause boiling water makes clearer ice.
And you make a block of ice at the top of the wall.
Then, you just let it freeze?
And you just let it freeze in the existing cold conditions.
It's very, very cold.
It's a lot more brittle.
And that's not what we want.
So we temper it and it softens.
And then, we sculpt it.
When ice is connected together, when the mass of the ice
itself is greater, it actually melts slower,
because it keeps itself cold.
The outer edges melt, but the interior doesn't.
So piece it together by searing each plate
and connecting them together, sort of like how
you would build a wall.
It really is a man-made glacier.
Over time, it would want to spread out.
So in order to sort of keep it stable,
I would think you'd have to put some support structures,
like those buttresses in old cathedrals,
to kind of keep it in place.
But it's a magical wall so anything is possible.
Well, if I had infinite money and resources,
like an infinite supply of ice, if you take away
all the limitations in that regard
and you have the proper tools to move that kind of weight
in pieces, I don't see why you couldn't build almost anything.
We can build the wall any way that they
want us to, as long as we have a stamped set of engineering
plans, because that's the most important thing to have.
If the engineer stamps it, I'll build it.
So with a little bit of magic, there
you have it Georgie Mar-tan.
Science seemingly can find answers for almost everything.
Although, in this case not for magic.
If you're thinking magically enough,
there are 17 different types of water ice
that we know of in our universe.
Ice as we put it in our drinks and stuff, that's just ice one.
When water freezes, those little bent H2O molecules
form into lattices.
And maybe, just maybe, one of those lattices
is stronger than regular old ice.
We can't actually make them outside of a laboratory
or another planet, but there are hundreds
of possible configurations on our planet
and elsewhere in the universe.
So what if the children of the forest
made the wall out of some other type of water ice?
That would seem like magic, even to today's scientists.
And it would still fall within the realm
of the laws of physics.
While talking to these experts about building
a giant wall of ice, I sort of started getting parallels
to climate change.
We're losing ice in massive quantities around our planet
right now.
And if you think of the Wall of Ice as the ice on our planet
and the dragon as climate change,
you would never think that all that ice would
disappear or cause the destruction of all mankind
until it happens.
There was a recent study that just came out,
looking at 19,000 glaciers, all around the world.
So these are glaciers on mountains, as well as
in polar regions.
And they're melting five times faster
than they were in the 1960s.
When you melt ice and you warm those regions,
you really disrupt the whole climate system on earth.
Not only is it getting warmer everywhere,
but the ice itself disappearing is
making bigger swings in weather than we've had before.
I hope that you agree that Game of Thrones
is a wonderful piece of art and a thoroughly enjoyable fantasy
fiction.
And while it does seem to be rooted
in some semblance of physical reality,
there is a lot more magic and mystery in the pages
of this world without dragons or zombies.
The sheer scale of the wall just helps transport us
to a fantastical world, where people
are capable of doing incredible things,
even if they can't form a stable government.
I hope that season 8 ends on a high note,
because it-- oh my god.
Please tell me what you think is going
to happen in the comments.
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Thank you guys.
And thank you for watching.
So while the giant wall of ice that we see and read
about in Game of Thrones wouldn't actually
be possible with engineering that doesn't involve magic,
it is still a lot of fun to think about.
So again, thanks for watching.
I'm Trace.
And I'll see you in the future.
Game of Thrones season 8.
[SINGING]
But if I had to live anywhere in game of Thrones,
I would definitely live in Dorne,
because it's beautiful there.
Long flowing outfits and wine and snacks.
Sign me up.
I like the snacks.
I don't know what snacks they have, but I'm ready for them.