Original subtitles

Narrator: worldwide, 300 Million surveillance cameras

Are watching us.

On our streets, at work, and in our homes,

They capture things that seem impossible.

It defies the laws of physics.

♪♪

Narrator: experts carry Out forensic analysis

Of these unusual events.

There's got to be some Explanation for what's going on.

♪♪

Narrator: coming up...

A massive shock wave hurtles Towards a terrified driver.

Moran: is this an act of terror?

Did terrorists get their hands On a very powerful weapon?

♪♪

Narrator: an alien-like signal Rises up from the abyss.

Could this be a godzilla-like creature?

Narrator: an unseen force Controls a perfect circle of ice.

I just can't believe for A minute it's natural.

Narrator: and a bizarre glowing orb Swoops across a remote forest road.

What we're viewing may Be a very rare phenomena

Which has not been caught on camera before.

♪♪

Narrator: bizarre phenomena...

Mysteries caught on surveillance...

What's the truth behind This strange evidence?

♪♪

A dash cam captures an apocalyptic event.

♪♪

You can see a shock wave Coming towards the car.

♪♪

Whatever has happened Has been catastrophic.

Van duren: fireball's huge.

Size of houses.

I thought I was gonna die.

What the... Oh, my god!

Narrator: investigators race To explain the terrifying blast.

Did it fall from the sky?

Where's next?

Narrator: tianjin, northern china...

A town of 13 million people And vital to the nation's economy.

Price: tianjin is a large coastal Town in china with a big port.

It's one of the closest Metropolitan areas to beijing.

Narrator: yearly, 550 million tons Of cargo pass through the docks.

Trade with 600 ports in 180 countries

Makes keeping tack of it all Nearly impossible for outsiders.

♪♪

August 12, 2015, 11:33 p.M.

♪♪

Dash cam video records a stop

At a dockside entry gate.

What seems like a normal kind of stop

In front of a gate turns Very bad very quickly.

♪♪

Price: night turns into day,

And there's this bright Light ahead of the car.

Narrator: instinctively, the Driver begins to back up.

But it's not enough.

And then as the car starts to reverse,

There's a second explosion.

♪♪

It's much, much larger than the first.

And there's kind of bits of flying material

Going everywhere.

It's really scary.

You can see the shock Wave coming towards the car.

♪♪

Bends the trees by the car,

And the guard gate Has actually bent itself.

The explosion is a little bit reminiscent

Of a nuclear explosion,

Because you see this flash of bright light.

However, the light stays bright

A bit longer than a nuclear explosion,

And luckily, you don't See any mushroom cloud.

Narrator: an american Citizen, daniel van duren,

Is visiting friends in the city.

He witnesses the event From a friend's apartment.

Van duren: what the...

I seen fire raining down Everywhere around me.

♪♪

Oh, my god!

Massive fireballs,

Containers flying throughout the city.

Narrator: hundreds of shipping Containers, each 25 tons,

Are blasted into the sky like fireworks.

They offer a vital clue.

Van duren confirms the two explosions

Come from the heart of the docks.

♪♪

It was something out of a nightmare.

Narrator: the following morning, van Duren returns to his own apartment

Closer to the blasts.

It has been destroyed.

Van duren: holy moly.

We were just stunned.

I mean, it blew out every Window in the building.

It rained glass throughout the whole city.

Oh, my god.

It just destroyed everything for miles.

♪♪

Narrator: seismic monitors reveal The devastating second blast

Is seven times more powerful than the first

And equivalent to over 20 tons of tnt.

The bright light

Followed by chunks flying everywhere

And bits of what must be buildings.

To be present in tianjin on The night of that explosion

Would've been something Really, really unbelievable,

Something totally terrifying.

♪♪

Narrator: the blasts take The lives of 173 people,

Injuring a further 800.

Investigators race to find the source

Of the terrifying explosions.

Farrow: this is a major world event,

And so it's important to figure out

What went wrong to cause so much damage

And so much loss of life.

♪♪

Narrator: van duren's Visit to tianjin coincides

With the annual perseid meteor shower,

A stream of space rocks Grazing the earth's atmosphere,

Lighting the sky with Bright trails and fireballs.

He's watching the skies for meteors

When the first explosion strikes.

♪♪

The very first explosion

Was just pretty much the light,

The sky lighting up.

We thought a meteor hit.

♪♪

Narrator: hundreds of Golf-ball-sized meteors

Pierce the earth's atmosphere every day,

But those large enough to Generate a shock wave are rare.

You see sort of fire Raining down from the sky.

The last time we saw that Was an air burst meteor

Above chelyabinsk in russia.

♪♪

That knocked through Windows and hurt a lot of people.

Narrator: but when experts analyze The tianjin surveillance footage,

They realize something's missing.

Moran: when there's a meteor, You expect to see a streak

Coming out of the sky And the trail of the meteor,

And you don't see that here.

It's dark until the very Moment of explosion.

♪♪

It's clear that something Exploded on the ground,

And now the question is what exploded?

Narrator: in the immediate Aftermath of the tianjin blasts,

Chinese authorities impose a news blackout.

There's no information coming out.

It's completely clamped down.

Narrator: china is deeply secretive

About issues relating to homeland security.

Tianjin is a strategic port

Directly supplying the chinese capital.

Investigators consider the possibility

That the docks were targeted.

My immediate thought Upon seeing that footage

Is this is a city that's being bombed.

♪♪

If this is a bomb, it must be a big one.

♪♪

Narrator: a bomb detonating in Docks vital to china's economy

Raises a chilling possibility.

♪♪

Is this an act of terror?

Did terrorists get their hands On a very powerful weapon?

♪♪

Narrator: coming up, an unexplained Sound echoes from the abyss.

It's very strange, because there Should be nothing down there

To make a noise.

Narrator: scientists investigate A bizarre luminous presence.

We are ready to do a plasmoid discharge.

7,000 volts.

In three, two, one.

♪♪

Narrator: and investigations in China reveal a deadly cargo

At the dockside.

We know some of the chemicals in the area

Were potentially bomb-making material.

♪♪

This stuff is deeply, deeply unstable.

♪♪

Narrator: analysts investigating Two successive dockside explosions

Wonder if terrorists are to blame.

Moran: given that this Takes place at the docks,

My immediate question is What is being transported

In and out of this area?

Narrator: investigators believe The port's trade in raw chemicals

Could explain the blasts.

We know some of the chemicals in the area

Were potentially bomb-making material.

♪♪

Narrator: research chemist andrea Sella from university college, london,

Is an expert in chemical analysis.

He studies the list of Compounds stored at the docks

At the time of the explosion.

Among them is a highly volatile chemical.

One of the key things that was there

Was this material here Called calcium carbide.

Now, calcium carbide Is absolutely notorious.

Narrator: sella sets up a Laboratory-scale demo

To show what makes the crystalline chemical

So dangerous.

Sella: we'll take this calcium carbide,

And now we're going to add water.

You can see that it Immediately starts to fizz.

Narrator: the violent chemical reaction

Produces invisible, highly Volatile acetylene gas.

Now what we'll do is we will Light the gas that is produced.

Watch.

And you can see that It burns very, very fast,

And it's actually got a bit of a pop to it.

Farrow: you might be Familiar with acetylene,

'cause people talk about acetylene torches,

Which are what you use to cut steel.

So it's very, very hot. It expands very quickly.

And water is pretty much the last thing

That you want to put on calcium carbide.

Narrator: yet scientists are baffled.

How did water make contact with The chemical to trigger a blast?

♪♪

A review of the dash cam footage

Confirms no rainstorms that night.

♪♪

Instead, news reports hint At a chain of unlikely events

Culminating in a nightmare scenario.

♪♪

40 minutes before the first explosion,

A fire breaks out near the warehouse

Storing calcium carbide.

Which the fire crews try to extinguish

By spraying on water.

When they poured the Water onto the burning fire,

What they got was this highly Flammable and explosive gas.

♪♪

The firefighters couldn't have known

That there was calcium carbide there,

And so when they put The water on, accidentally,

They made the situation a lot worse.

Van duren: oh, my god!

Narrator: investigators believe

The key to the second, Much larger explosion

Could lie with another Dangerous chemical at the docks.

Ammonium nitrate was Being stored nearby, as well,

And ammonium nitrate's a Very dangerous chemical.

It's a precursor to fertilizer.

It's also a precursor to tnt, to dynamite,

And it's used in a lot of kind Of explosive-making devices.

Narrator: andrea sella Demonstrates what happens

When a spark meets even a Small amount of ammonium nitrate.

♪♪

So, I'm gonna light it with a sparkler.

We'll lay it down, and You'll see almost immediately

That the fire breaks out,

And it's really very, very fast

And very, very intense.

♪♪

Narrator: the tiny pile creates a Sudden, sustained tower of flame.

Investigators believe

Sparks from the initial acetylene explosion

Reaches an 800-ton stockpile of This explosive ammonium nitrate

To trigger the second cataclysmic blast.

The explosion in tianjin

Really is a kind of three-headed monster.

What you have is an initial fire,

Which is then aggravated By well-meaning firemen

Who cause an explosion.

♪♪

And that triggers the Second massive detonation.

♪♪

Chemical nightmares Don't get worse than that.

♪♪

Narrator: for daniel van duren,

It's a nightmare he won't easily forget.

I've watched it hundreds of Times, especially right after.

So I'll never forget

Every little detail about it.

Let's go!

I didn't know if we were gonna live.

There's no words, really, to explain

Something that monumental.

♪♪

♪♪

Narrator: now an ominous signal Rises from the ocean depths.

[ humming ]

I haven't heard anything like this before.

It's hard to imagine a living Being making that kind of sound.

[ humming ]

Narrator: analysts consider if a war Is breaking out beneath the waves.

We're on the verge of starting

An underwater military arms race.

Narrator: others fear a Monster is rising from the deep.

Very weird sounds made by Really big things in the ocean.

Could this be a godzilla-like creature?

♪♪

Narrator: october 14, 2014.

The western pacific ocean.

A research vessel navigates This vast expanse of water.

Onboard, a team of scientists From oregon state university.

The crew lowers a deep-water Drone into the water.

Its destination... 35,000 feet,

7 miles down.

♪♪

Their mission... To explore The deepest place on earth,

The mariana trench.

Copley: it's bigger than the grand canyon.

It's a lot deeper than the grand canyon.

And in fact, from the surface, If you took mount everest,

And you turned it upside down

And dangled it into the Trench, the top of mount everest

Wouldn't reach the bottom of the trench.

Narrator: the drone begins its descent.

It takes around three hours

To reach the deepest Point on the ocean bed,

A forbidding black abyss Named challenger deep.

More people have walked on the moon

Than have experienced these depths.

Here, the water pressure

Is a bone-crushing 8 tons per square inch.

They call it hadal, meaning hades.

It's like hell.

♪♪

Narrator: two hours into the Mission, the drone's onboard sensors

Pick up an unnerving sound.

[ whirring, humming ]

Lacasce: I haven't heard Anything like this before.

It's very unusual.

[ whirring, humming ]

Sounds like a movie Special effect, you know?

Like a laser gun or something like that.

[ whirring, humming ]

Narrator: the research team posts The unidentified signal online.

Experts can offer no explanation.

This is one of the most inhospitable places

On the planet.

It's very, very strange, Because, theoretically,

There should be nothing Down there to make a noise.

What could be down there That's creating this sound?

Narrator: coming up, a Remote security camera

Captures a strange invader.

You just have the appearance Coming out of nowhere

Of this orb.

♪♪

Narrator: and scientists Investigating the eerie signal

From the mariana trench Check for signs of life.

[ whirring, humming ]

Narrator: a sinister signal From the bottom of the ocean.

Marine biologists investigating It make a remarkable discovery.

It was very common for people to say

That the deep sea was like a desert,

Almost devoid of life.

Well, it turns out that the Deep sea is actually quite diverse.

There's a huge variety of animals.

Narrator: footage from unmanned Subs mapping the trench

Reveal species that don't exist

Anywhere else on the planet.

Crustaceans over a foot Long patrol the ocean bed.

The ghost fish, with colorless eyes

And translucent, scaleless skin.

It survives pressure 1,000 times greater

Than at the surface.

But these strange marine Creatures are too small

To account for the loud, disturbing sound

Caught by the deep-sea sub.

Carney: I would think the sound Energy generated by a small crustacean

Living in the mud would not carry very far.

♪♪

[ whirring, humming ]

Narrator: scientists Reexamine the recording,

Searching for clues to its origin.

Paleo-geologist darren naish

Believes the location of The sound may yield clues.

♪♪

The mariana trench forms part of a vast,

Highly unstable zone Called the pacific ring of fire.

Could it be a sound, something To do with geological events?

Bell: this is a really Active part of the world.

75% of the active Volcanoes lie in this zone,

And 90% of all earthquakes That happen on earth

Are from this area.

Narrator: records show that The most violent earthquakes

On the planet strike in this zone.

When rocks slip and we have an earthquake,

They produce vibrations.

We call them seismic waves.

We detect these seismic waves

Using instruments called seismometers.

Narrator: experts check seismometer data,

Looking for a match with A signal from the deep.

But they draw a blank.

Earthquakes produce Low-frequency acoustic waves,

Which are very low in pitch.

This sound had a range of frequencies,

So it couldn't have been Produced by an earthquake.

♪♪

Narrator: analysts examine each Part of the signal separately.

[ whirring, humming ]

It's got a series of Different complex parts.

It sweeps through the frequencies.

And it's got this weird Metallic twang at the end.

The sound, particularly that metallic twang

It has at the end, sounds very robotic.

Maybe this could be a sound Which man has produced.

Narrator: experts consider What kind of manmade objects

Could be sending out signals Deep beneath the ocean.

A clue lies in the proximity Of a large u.S. Naval base

On the nearby island of guam.

Guam is a strategically vital scrap of land

For the united states. It Represents a stepping stone

Between the united states and towards asia,

Right in the middle of the pacific.

Narrator: intelligence reports suggest A military technology arms race

Is playing out in the ocean depths.

♪♪

The u.S. Military is pumping millions

Into developing unmanned Underwater systems.

Narrator: and the u.S. Isn't The only military superpower

Operating near the mariana trench.

What we do know is that the chinese

Are now using highly sophisticated,

Remotely operated drones underwater

To try and control some Of these stretches of water.

Narrator: with both the u.S. And china

Engaged in underwater drone testing,

The tension in these waters is mounting.

We're on the verge of starting

An underwater military arms race.

There's nothing to stop these Drones from being weaponized.

Narrator: analysts consider if The mysterious metallic signal

Could indicate an Escalation of hostilities.

♪♪

Narrator: coming up, a Razor-sharp spinning circle of ice

Cuts through a frozen river.

What could provide the force

To start that whole disk rotating

In the first place?

Narrator: and experts realize their Signal is not the only mysterious sound

To rise from the ocean's depths.

There's the so-called "Star wars" sound...

[ pulsating huming ]

...Another weird noise made In some oceans of the world.

♪♪

Narrator: experts are investigating The source of an ominous signal

From the black abyss of the pacific's

7-mile deep mariana trench.

[ whirring, humming ]

Some fear it could be a new type of sonar

Developed by the military to Weaponize undersea drones.

The latest military Developments use sonar pings

To enable the drones to Lock onto their targets.

♪♪

Narrator: but marine biologist joe Lacasce believes the erratic nature

Of this signal rules out this theory.

It has a metallic ring to it,

So it sounds a little bit manmade.

[ whirring, humming ]

But if it were some pinging sound,

You'd expect it to be more regular.

This wasn't quite regular, either,

So it's very unusual.

[ whirring, humming ]

Narrator: scientists turn their Attention to a biological source

For this strange signal.

Paleo-geologist darren naish cross-checks

The metallic-sounding part of the recording

With known marine species Throughout the pacific

And gets a partial match.

There are already some similar, complex,

Sweeping metallic sounds that are confirmed

As having been made by Certain whale species.

There's the so-called "Star wars" sound

That's been attributed To dwarf minke whales

In some oceans of the world.

[ pulsating humming ]

Different whales have Slightly different calls

In different parts of the World. It's almost like...

In some cases, it's like they Have their own kind of dialect

Or accent.

So it might not exactly match recordings

From dwarf minke whales elsewhere,

But it has a lot of the characteristics.

Narrator: if the signal is biological, Oceanographer john hildebrand

Believes the sound's location

Means another species of whale

Is the most likely source...

The bryde's whale.

When we look at the Calls of bryde's whales,

There's a call recorded In the marianas trench

To the north of this

That matches very well Those characteristics.

♪♪

Narrator: but hildebrand Admits there's a problem.

Hildebrand: it matches well In the low-frequency part,

But it's missing some of the other parts.

[ whirring, humming ]

Narrator: it leads some to fear The sound may be produced

By an entirely unknown undersea entity.

There might be all kinds Of creatures down there

That we haven't yet Recorded or observed at all.

♪♪

Does make you wonder what Kind of strange creatures

Might be hiding in the Depths of our oceans.

How might they have evolved into monsters

That we could've never imagined?

[ whirring, humming ]

Narrator: now a mysterious flying object

Lights up a deserted forest road.

♪♪

It is a bit "Close encounter" -esque.

Narrator: the strange glowing Orb baffles scientists.

This does seem just so weird, so alien.

A phenomena which has not Been caught on camera before.

♪♪

Narrator: march, 2013.

Prokopyevsk, russia.

♪♪

A remote woodland wilderness

Between mongolia and kazakhstan.

The only thing stirring here Are the creatures of the forest.

[ animal howling ]

♪♪

The dead of night along a forest track.

Light from a security camera Reveals a strange invader.

♪♪

You just have the appearance Coming out of nowhere

Of this orb.

♪♪

It is a bit "Close encounter" -esque,

Based on the fact that it's Glowing and it's flying so low.

It's very strange, the altitude.

Narrator: the mysterious orb drifts Effortlessly through the scene,

And then it's gone.

It travels right down the road Until it disappears out of view.

Narrator: experts reviewing The recording are mystified.

This is a rather odd phenomenon,

'cause you really cannot see Any activity going on in the area,

No other strange lights.

So it's a little different From what you would expect.

♪♪

My initial reaction was "What is it, why is it flying,

And why is it glowing?"

Narrator: video analyst conor mccourt

Studies the footage frame by frame.

When he enlarges the object, He finds a potential obstacle

To identifying its true nature.

Mccourt: the ball doesn't Have any detail on it.

What we're getting is a Whiter-than-white area.

Narrator: mccourt reasons this white glow

May not be produced by the orb itself,

But instead results From a nighttime exposure.

If there's an Over-saturation on the object,

You get a thing called blooming.

And what blooming is Is the whiter than white,

And it gives it, like, a Ghostlike orb kind of quality,

And it erases the detail In the object itself.

♪♪

Narrator: he believes the strange Glow is the security camera's own light

Reflecting back off a White or pale surface.

Mccourt: the reasonable explanation here

Is that this is some kind Of light-colored object,

Like maybe a white butterfly.

Nickell: if you do shoot Lots of footage at night,

You will see this effect From flying insects.

You will see that they are illuminated.

They look very white.

I'm confident that it's bird Or insect, something like that,

And the light is lighting it up.

Narrator: but some experts Detect a flaw in this explanation.

♪♪

Price: flying animals have wings.

Animals with wings flap.

If there were flapping going on,

The orb theoretically Should be going up and down

As it moves along, but it doesn't.

It's very smooth.

Narrator: whatever this is, it Seems to be on the very edge

Of scientific understanding.

What we're viewing on here May be a very rare phenomena

Which has not been really Caught on camera before.

♪♪

Narrator: coming up, a perfect circle Of ice appears out of nowhere.

Where does it come from?

How does this form?

♪♪

Narrator: and scientists Investigating a strange flying orb

Get a lead from its eerie glow.

This may be something that could be due

To an electrical discharge somehow.

Narrator: researchers studying A mysterious, glowing entity

Consider whether it could Be an electrical phenomenon.

You may not realize, But there's electricity

All around us, all the time.

Electricity has a very Strange phenomenon to it,

So this may be something that could be

Due to an electrical discharge somehow.

Gay: this charge can Build up in the atmosphere.

It can build up to be lightning.

[ thunder crashes ]

Narrator: in a lightning strike,

Electricity charges Gases in the atmosphere,

Transforming them into plasma.

[ thunder crashing ]

Plasma is defined as the Fourth state of matter.

A state of matter

Where the electrons Have become unassociated

From the atoms that They want to be part of.

Narrator: the creation of plasma Releases a vast amount of energy.

One of the ways it can give off Energy is through visible light.

And that's what we can See darting across the sky.

[ thunder crashing ]

♪♪

Narrator: physicist scott dubowsky

Has an in-depth understanding of plasma.

He believes the intensity of the orb's glow

And its floating, spherical Form are vital clues.

The observables that you see in the video

Tell me that it could be plasma.

Narrator: dubowsky builds a Bucket-sized rig in his lab

To re-create the effect in the video.

He aims to ionize water vapor

By sending a massive electrical discharge

Through a pair of electrodes

To create a floating ball of plasma.

Dubowsky: and the idea is here That this electrode setup

Is then submerged in This five-gallon bucket,

Which is full of a weakly Conductive solution of water.

♪♪

And we're charging now.

We are fully charged up,

So we are ready to do a plasmoid discharge.

7,000 volts in 3, 2, 1.

♪♪

You can see we get a plasma

That forms at the center of that electrode,

And it forms a ball...

A ball that rises up and away From that central electrode.

Narrator: it looks just Like the self-contained,

Floating ball captured By the surveillance camera.

It is possible to create

These free-floating balls of plasma.

♪♪

Narrator: dubowsky Suggests the high humidity

And huge electrical discharge

Required to generate a plasma ball

Can be found outside the laboratory

When a lightning bolt strikes the ground

And discharges around a billion volts.

The idea is that you have lightning

That strikes a piece of soil

And energizes that material That eventually forms this ball.

[ thunder crashes ]

This is a possibility of What we see in the video...

A ball of plasma coming In to view on the screen

And then traveling down the road.

♪♪

Narrator: if this is the Case, it's a spectacle

That scientists call ball lightning.

Now, one of the things that We notice about ball lightning

Is the way it moves.

And one of the main factors That can create this movement

Of ball lightning would be the presence

Of a strong magnetic field To help force it along its way.

♪♪

Narrator: in the laboratory, Physicists use vast magnetic chambers

Weighing up to 23,000 tons

To maintain plasma in a ball shape.

♪♪

Wallace: now, in this video, We see this plasma ball or orb

Floating across the sky,

But there's no external forces

Being able to contain it in that shape.

So what is causing this Ball to be able to fly there

And maintain the shape?

Now, could it be the magnetism of the earth

Or some other magnetic Force in the area causing this?

We really do not know.

Narrator: the mystery deepens When investigators play

To the end of the surveillance tape.

♪♪

All of a sudden, it reappears,

Coming straight at the camera again.

Narrator: the returning orb casts doubt

On scientists' plasma ball theory.

So here you have a Phenomenon that's very odd.

You have a light just Out of nowhere it appears,

And it starts traveling down the road.

A few seconds later, you get another one

Coming back the opposite direction,

A little bit closer to the road.

Why does it come back?

You have no actual cause of this happening.

We don't know why.

♪♪

Narrator: now...

A sheet of ice seems to come alive.

There's this weird ice disk

Going around and around.

It's a perfect circle.

Narrator: analysts fear it's a Sign of toxic contamination

In the water.

Walters: radioactive Waste will give off heat,

And it can create all Sorts of strange phenomena.

♪♪

Narrator: omsk oblast, siberia...

One of the coldest places on earth.

♪♪

Winter temperatures Here plummet to minus-50.

♪♪

January 2016.

A river frozen in time scars the landscape.

Sella: you've got this big River in a bit of a gorge.

It's clearly very cold,

And the surface of The river is frozen over.

Narrator: nearby cameras Capture a bizarre sight.

We look over a frozen River with what appears to be

Just a perfect circle of snow-covered ice

Rotating in the middle of it.

Narrator: experts are baffled.

A block of ice with this Kind of geometric perfection

Is out of this world.

I just can't believe for A minute it's natural.

♪♪

Narrator: what's more, an unseen force

Appears to be controlling the spinning ice.

The question I ask Myself is how did that disk

Begin to move in the first place?

Narrator: scientists Discover a circle of ice

Spinning in the middle Of a frozen siberian river.

Measurements reveal it to Be over 50 feet in diameter.

Some believe its near-perfect shape

Holds a clue to its origin.

What springs to my Mind looking at this video

Is the military maxim

That if you see straight Lines and perfect circles,

That means that man's around.

Narrator: analysts check for Human activity in the area.

They discover an abandoned

Soviet weapons testing site nearby.

♪♪

They dumped a lot of the Nuclear waste into rivers.

Radioactive waste will give off heat,

And it can create all Sorts of strange phenomena.

Narrator: but in this instance, Investigators can find nothing

That links nuclear waste

To the behavior of The bizarre spinning ice.

♪♪

Experts shift their Focus to the river itself.

Perhaps there's some Kind of eddy in the flow

Which is actually Causing this thing to spin.

Farrow: sometimes there's Obstructions on the bottom

Or on the side that Twist and turn the river

And create very weird currents and eddies.

Narrator: but close inspection Of the tape confirms

That the river is moving too slowly

To generate any unusual currents.

When you look closely at the footage,

The river doesn't seem to be moving at all.

Farrow: we don't see any Of those weird currents

In the rest of the river,

So something else must be happening here.

Narrator: the footage Comes to the attention

Of material scientist suze kundu.

She suspects the ice is spinning

Because of a peculiar property of water...

That solid ice is less Dense than liquid water.

That's why ice floats.

Nothing else around us behaves in this way.

Water is pretty special.

Narrator: kundu sets up an experiment To show what happens to ice

When it melts in a tank of warmer water.

She freezes a scaled-down ice circle

To represent the disk in the footage.

♪♪

As the ice melts, it releases water

That's a fraction of a degree above zero.

Water just above the freezing point

Is actually the densest form.

Because it's more dense, It wants to drop down

To the bottom of this relatively Warmer water around it.

Narrator: this denser water Displaces the warmer water below it.

♪♪

However, in doing so, it creates A slight sideways movement

As it tries to drop down.

Narrator: kundu believes this interaction

Between the cold and warmer water

Creates a vortex of turbulence.

♪♪

These little movements all Add up to create a vortex,

Like a very slow-moving water tornado.

♪♪

When you scale this up, The vortex that's created

As the ice melts is much larger

And, therefore, much stronger.

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Narrator: yet experts Still need to figure out

How this remarkable slab of ice

Got to be so geometrically precise.

Circles that perfect and that Large are pretty rare in nature.

Normally, you expect Some kind of irregularity.

Narrator: many believe it's The spinning motion itself

That creates a perfect circle From a jagged piece of ice.

As it rotates, it contacts The ice all around it,

Slowly grinding that piece of ice.

Farrow: the force is exerted Equally on every side,

Which will create a circle.

Narrator: scientists believe they Know how ice disks can form,

But no one has recorded one forming.

It means this phenomenon Is still incredibly rare

And mysterious.