Episode 5 Blow Your Mind

We are Dr Chris and Dr Xand van Tulleken

-and we're tracking down the most awesome...

-Incredible...

..and epic things in the universe!

Come with us and discover unbelievable things...

that will Blow Your Mind!

Blow Your Mind will be bringing you loads of top experts

and scientists to help you find out more about some amazing stuff.

From the arctic to elephants,

spaceships to sharks, and this week, it's all about ice.

Yes, frozen water. So hold on to your brains...

Because here's was coming up.

We once again explore the icy megalith that is Store Glacier,

wonder at the 3-D image of the glacier underwater...

..just as we're about to leave, Store delivers a parting gift

of astonishing scale and incredible natural destruction and beauty.

And we look ahead to the next leg of our incredible

exploration, the mega-berg.

We've been following Chris's adventure

living on Store Glacier in Greenland with a bunch of ice scientists.

We've seen some incredibly mind-blowing stuff,

like massive ice tunnels big enough to fit

two double-decker buses on top of each other inside...

And divers diving so deep under the ice,

the water eventually became warmer...

And the bonkersly brave glaciologist fixing

a GPS tracker to the top of an ice tower. It's been incredible.

Find out more about glaciers and icebergs.

Well, today, I'll be showing you the next step in the adventure

as we leave our glacier in Greenland and set off

in search of a mega-berg.

A mega-berg?

That sounds so cool. I bet you were sad to leave the glacier

because you'd seen so much there,

-but going to a mega-berg sounds even better.

-It does, doesn't it?

We were all excited to find the mega-berg, but before we left,

the team still had a few things to do

in their floating science lab, the Gambo.

Aboard the Gambo, our experts are...

..Chris Packham, wildlife and nature expert...

..Helen Czerski, physicist and oceanographer...

..Alun Hubbard, glaciologist and ice expert...

..Richard Bates, geophysicist and ice expert.

Their little research yacht, Gambo,

had returned to the perilous waters they'd sailed during

the sonar scanning that had helped the team

to map out the front of the glacier.

Chris Packham had spotted something then,

an area of water bubbling up that could help them

understand the route of meltwater from the glacier to the ice front.

They returned to investigate.

This body of water here is very different than everywhere else.

There's brash ice everywhere and yet this is open,

it's turbid and parts of it are boiling.

Well, not boiling, but there's a lot of Jacuzzi action.

Jacuzzi action, that's a pretty cool word for it.

The plumes, these jacuzzis, I think, I suspect are absolutely

fundamental to the processes going on in the iceberg.

So Alun believed these plumes, or jacuzzis, played

a part in the formation of icebergs and the team wanted to find out

if they were connected to the hidden tunnels within the glacier.

Richard is an imaging expert

and joined the team to turn the underwater scan into a 3-D image.

They hoped the 3-D image would have the answers

they were looking for, so Richard wasted no time.

What have we got, then?

This is the side-scanning sonar results,

but you've transformed them with some software into something...

Yeah, that's right, yeah.

I mean, if I put that into 3-D, you can start to see, now...

So that's just the seafloor, no ice?

That's just the seafloor we're looking at.

We can put the ice back into that and there you can see the ice

stretching from the north side to the south side of the glacier.

Look at that!

But then round the corner, into that, I'm beaming a huge cave.

And this on the south side, here, that's where the plume's coming from?

Exactly. These places match where all that water is coming out.

This was the first time this had been seen.

The 3-D image clearly showed caves which were

the mouths of the sideways tunnels coming from under the blue lakes,

pumping out millions of litres of fresh meltwater into the sea.

These tunnels are the source of the water for the jacuzzis that

Chris Packham had spotted earlier.

It shows that most of these tunnels come out at the base of the ice,

but not all of them.

Is that a cave in the face of the glacier, then?

Yes, it is a hole or a cave,

or at least a heavily-fractured zone, in there.

That's coming up within the face and that's something very new.

-What an astonishing view!

-It's lovely, isn't it?

You can really visualise the fact that this glacier front

-is not just a big flat wall.

-This, for me, is it.

Our time on the Gambo has been very well spent. Look at that.

These amazing results caused the team to come up with

a new theory about how mega-bergs are made.

Alun now believes that these plumes of water, or jacuzzis,

melt the glacier front into horseshoe shapes that form bays,

leaving massive headlands sticking out, which eventually break off.

What we're seeing is massive headlands with towering

ice above the water line.

They're 100, 120 metres high in places

and that's where we're getting the really big mega-bergs forming.

There it is. After three weeks at the glacier,

all the pieces of research now fit together.

The meltwater from the blue lakes flowing through the moulins,

the speed the glacier moves, the discovery of the undercut,

the sea temperature, it all adds up to explain how bergs are born.

That's right, and the 3-D pictures are amazing, aren't they?

It's fantastic to be able to see these huge tunnels emerge,

carry all that water to the sea.

It was an incredible few weeks, but I think we should leave it up

to our friend, the physicist Helen Czerski, to sum it all up.

We've seen that huge amounts of meltwater are produced at the surface

and they percolate down into the ice through moulins and crevasses.

And one theory was that all that water flowed down to the bedrock

and underneath the ice,

lubricating the movement of the glacier as it surges forward.

There's a new theory that water could be taking a different route

through a small number of huge tunnels, and that helps melt

away the ice where the tunnels have formed and so we get these bays.

And in between the bays, there are headlands,

and those seem to be the bits that break off intact and that

form the huge lumps of ice that carry on out to the open ocean as icebergs.

Well, I couldn't have put that better myself,

Chris, I completely understand, now.

The formation of bays leaves these other bits sticking out

and eventually they break off and, hey presto,

you've got yourself an iceberg.

That's it, and they can be absolutely enormous,

as you're going to see in a little bit.

I suppose the thing is, you never actually know

when an iceberg's going to form or carve,

-so capturing it on camera must be really difficult.

-Completely.

Every day, we'd been hoping that we'd see a mega-berg carve,

but we hadn't.

Then, on our last day, just as we were packing for the move,

Store Glacier decided to give us an incredible leaving present.

And what a sight. Feast your eyes on this.

Just as we were packing up, it happened...

A classic demonstration of the effect

of everything we'd discovered.

-Wow!

-Oh-ho-ho!

-Oh, wow, look.

-That is massive.

Just as Alun had predicted,

a whole headland started collapsing.

It was the most enormous

and most violent carving,

or birth of a berg,

we'd seen so far.

Just phenomenal.

This was a mega-berg

to end all mega-bergs.

That iceberg is a kilometre across.

As the mighty berg rose from the water,

you could see a line in the ice toward the left-hand end.

The line separated the ice that was above the water on the left

and the massive amount of ice that was below the water on the right.

Oh-ho-ho!

So there's a wave of, kind of, fractures going along the top

end of it, so all the stuff that was the cliff is now just crumbling.

And that's the first time the water in that has seen the light of day

for thousands of years.

We talk about glaciers as, like, a metaphor for slowness and tedium,

but this thing is completely alive.

That is one of the biggest bits of natural destruction

I've ever seen in my life.

It was fantastic.

The glacier had given us an amazing leaving present, a mega-berg.

All of the things the team had learnt

so far was demonstrated before their very eyes.

And now that I've seen all of what's going on to produce just one

iceberg, all of the things that happen behind the scenes,

if you like, watching an iceberg carve is a much richer event.

We've been trying to measure these things in St Paul's Cathedrals,

but I wouldn't know where to start.

I wonder where that iceberg will end up. Where's it going to drift to?

Where's it going to finally melt?

Where's it going to be when the last little piece,

the size of a golf ball,

melts and becomes part of the ocean?

Makes you wonder, doesn't it?

Wow! I just don't know what to say, that was so incredible!

It was indeed an awesome sight.

To be honest, it was amazing being there at the time,

but these camera shots are astonishing.

I think they really capture the moment brilliantly.

You know what I'm going to ask, don't you?

I think I can guess. Could it be that you want to see it again?

Who wouldn't?

Not many people wouldn't, I don't think,

and I'm not one of those that wouldn't want to...

-Do you want to see it or not?

-Yes.

Run the VT, guys!

That was absolutely amazing.

It was a massive amount of ice,

creating an absolutely enormous mega-berg.

I loved to see it when it just reared up out of the water

and created such gigantic waves.

-Wow.

-Oh-ho-ho!

Really incredible.

That was even better the second time around, Chris,

that was absolutely awesome!

It was awesome, I was genuinely in awe of nature

and so was everyone else watching.

What a brilliant leaving gift from Store Glacier.

It's a shame you didn't have much time to hang around

and appreciate it, but I guess you all needed to finish packing

and head off to the mega-berg to carry out more icy experiments.

Right, but packing wasn't quick,

it was a massive logistical operation to move everything.

We had tonnes of equipment to take

from the glacier and get to the iceberg.

So did you need to find an iceberg

big enough to land a jumbo jet on to get all the kit there?

No, Xand, we didn't take a jumbo jet,

but it was still a big, big job.

And before we go, I thought I'd give you a little teaser,

a little flavour of what lies in store next time,

when we get to the iceberg.

Nice one, Chris. I'm looking forward to this.

Next, we headed for an absolutely gigantic island of ice,

an enormous arctic mega-berg.

A huge piece of ice the size of a city,

an absolute wonder of the natural world.

This is super, super hard ice.

The science team were determined to discover what happens

-to an iceberg out at sea...

-Beautiful.

..and to understand the forces that cause it, ultimately,

to melt and disappear.

And it looks entirely without life,

an inhospitable lump of freezing freshwater floating in seawater.

It's just a stunning sight.

I've never seen a single piece of ice that is this big.

It's an absolutely amazing sight.

For two years, this berg had been the single biggest object

afloat in the northern seas.

It even had a name, the Petermann Iceberg.

Whilst on the iceberg,

we had huge challenges to overcome...

It's falling, here.

..from facing the biggest land predator

to surviving in one of the most unpredictable environments on Earth.

MACHINE BLEEPS

Whoa, that just looks unbelievably exciting. I can't wait!

-Well, you're going to have to wait, Xand.

-OK, then, I will wait.

I want to see what happens on that berg.

OK, well, make sure you come back to see things that will Blow Your Mind.