0:00:02 > 0:00:04We are Dr Chris and Dr Xand van Tulleken
0:00:04 > 0:00:07and we're tracking down the most awesome, incredible
0:00:07 > 0:00:11and epic things in the universe!
0:00:21 > 0:00:25Come with us and discover unbelievable things...
0:00:25 > 0:00:27that will blow your mind!
0:00:27 > 0:00:31Blow Your Mind will be bringing you loads of top experts
0:00:31 > 0:00:35and scientists to help you find out more about some amazing stuff,
0:00:35 > 0:00:39from the Arctic to elephants, spaceships to sharks,
0:00:39 > 0:00:43and this week it's all about ice. Yes, frozen water.
0:00:43 > 0:00:45So hold on to your brains!
0:00:45 > 0:00:47Here's what's coming up.
0:00:47 > 0:00:50We leave our camp above the glacier in Greenland
0:00:50 > 0:00:54and take to the iceberg-infested, high Arctic seas
0:00:54 > 0:00:56in the good ship Neptune.
0:00:56 > 0:00:59We're in search of the biggest, most gigantic object
0:00:59 > 0:01:01afloat in the Arctic Ocean
0:01:01 > 0:01:04and, finally, it appears out of the mist.
0:01:04 > 0:01:10The Petermann Iceberg, a mind-blowingly enormous megaberg.
0:01:10 > 0:01:13This looks like it's shaping up to be an amazing afternoon.
0:01:13 > 0:01:16I really want to see what it's like on this megaberg.
0:01:16 > 0:01:19I'm glad you're up for more of our icy adventures, Xand.
0:01:19 > 0:01:21It was fascinating seeing how bergs are born.
0:01:21 > 0:01:24I want to see what happens to them once they're free
0:01:24 > 0:01:25and floating in the ocean.
0:01:25 > 0:01:27That's what we wanted to do as well.
0:01:27 > 0:01:30It was a big move from the glacier to the bergs.
0:01:30 > 0:01:32There were a lot of us involved and a lot of equipment
0:01:32 > 0:01:36but we were all looking forward to seeing our new home.
0:01:39 > 0:01:42Here are the intrepid team members who headed for the berg.
0:01:43 > 0:01:48Chris Packham, wildlife and nature expert.
0:01:48 > 0:01:51Expedition doctor and all-round brave guy, me.
0:01:52 > 0:01:56Helen Czerski, physicist and oceanographer.
0:01:57 > 0:02:01Richard Bates, geophysicist and ice expert.
0:02:02 > 0:02:06Ragi Elson, Arctic sailor and the ship's captain.
0:02:11 > 0:02:15Myself and the team, scientists, camera crews and explorers,
0:02:15 > 0:02:18had swapped our beautiful glacier camp in Greenland
0:02:18 > 0:02:23for research vessel Neptune, a ship well-used to the Arctic waters.
0:02:25 > 0:02:29Neptune, its crew and skipper, had sailed down from Iceland
0:02:29 > 0:02:31to join the expedition,
0:02:31 > 0:02:35bringing with them years of experience sailing these seas.
0:02:38 > 0:02:41We were all about to set off across the Arctic Ocean
0:02:41 > 0:02:43on an ambitious two-week expedition
0:02:43 > 0:02:48to find a colossal megaberg on which to carry out more research.
0:02:48 > 0:02:51I think we just need to think through that plan, now.
0:02:51 > 0:02:54We were heading across these waters in search of an experience
0:02:54 > 0:02:58every bit as exciting, exhilarating and dangerous
0:02:58 > 0:03:00as our time on Store Glacier.
0:03:03 > 0:03:07That boat looks pretty serious, Chris. It's like a big, proper ship.
0:03:07 > 0:03:09Did it have to be that big to take all the gear?
0:03:09 > 0:03:11Well, we had got an incredible amount of kit
0:03:11 > 0:03:15but Neptune was a proper research ship and the skipper, Ragi Elson,
0:03:15 > 0:03:18was really experienced in those waters.
0:03:18 > 0:03:21It can be dangerous. You need someone who knows exactly
0:03:21 > 0:03:24what they're doing when sailing that close to icebergs.
0:03:24 > 0:03:27So did you just sail about until you found a suitable
0:03:27 > 0:03:30- iceberg and then just jump on? - Erm, not quite.
0:03:30 > 0:03:33The team already had a particular megaberg in mind
0:03:33 > 0:03:35and a good idea of what they wanted to find out.
0:03:35 > 0:03:36Take a look at this.
0:03:41 > 0:03:43The team had identified their target.
0:03:47 > 0:03:51In 2010, in the northwest corner of Greenland,
0:03:51 > 0:03:55an absolutely enormous piece of ice broke off the Petermann Glacier.
0:03:57 > 0:04:00Over two years, it then drifted south on the ocean currents.
0:04:02 > 0:04:05Vast chunks had broken off on four occasions.
0:04:05 > 0:04:09One of the biggest pieces was now over 1,000 kilometres
0:04:09 > 0:04:11from where it broke away from its mother glacier.
0:04:11 > 0:04:15It was stuck off the coast of Canada's Baffin Island.
0:04:18 > 0:04:21One of the scientists, Richard Bates, already knew this ice.
0:04:23 > 0:04:25So you've stood on this piece of ice before?
0:04:25 > 0:04:28That's right, yeah, back in 2009 we were up here.
0:04:28 > 0:04:30So before it actually broke off,
0:04:30 > 0:04:34we were there doing measurements on it, around it.
0:04:34 > 0:04:36This crack carried on around the back here,
0:04:36 > 0:04:39and this crack worked in its way towards it
0:04:39 > 0:04:41and broke that off as one chunk,
0:04:41 > 0:04:44and that is the iceberg that is working its way south.
0:04:44 > 0:04:48For the team, there was one key mystery they wanted to explain.
0:04:48 > 0:04:52That was, what are the processes which would lead
0:04:52 > 0:04:55to this massive piece of ice getting smaller and smaller
0:04:55 > 0:04:58and eventually disappearing into the ocean?
0:05:00 > 0:05:03The ocean has a huge amount of energy pushing and pulling
0:05:03 > 0:05:06and twisting, and I'm really interested to see how the
0:05:06 > 0:05:09iceberg stands up to all of those stresses.
0:05:12 > 0:05:15That's amazing, that one of the team had been on that ice before.
0:05:15 > 0:05:17I really liked that graphic.
0:05:17 > 0:05:20It really made it easy to understand the glacier
0:05:20 > 0:05:24and how the iceberg was born and just how absolutely enormous it is.
0:05:24 > 0:05:27I think it's like having your own speeded-up camera
0:05:27 > 0:05:29positioned in space.
0:05:29 > 0:05:32Yeah. Now, if the berg is as huge as all that
0:05:32 > 0:05:35and they think it's somewhere off the coast of Baffin Island,
0:05:35 > 0:05:37then it should be quite easy to find, I would think.
0:05:37 > 0:05:40Right, do you have any idea how big Baffin Island is?
0:05:40 > 0:05:44- About the size of the Isle of Wight? - OK, well think of it like this.
0:05:44 > 0:05:48The whole of Great Britain, from Land's End in Cornwall
0:05:48 > 0:05:52to Muckle Flugga in Shetland, the very north of Scotland,
0:05:52 > 0:05:54is 1,580 kilometres.
0:05:54 > 0:05:57Baffin Island is almost exactly the same size,
0:05:57 > 0:06:00so it's quite a big area to search.
0:06:00 > 0:06:02That is a big area! I hope they find it!
0:06:06 > 0:06:09After 36 hours at sea, looming out of the fog,
0:06:09 > 0:06:14we eventually saw an absolutely incredible wall of ice.
0:06:19 > 0:06:22At last, we had found our goal.
0:06:22 > 0:06:23There it is!
0:06:27 > 0:06:29It looks very frightening to me.
0:06:29 > 0:06:32It's full of cracks and fissures and cliffs and rivers.
0:06:32 > 0:06:34There's a huge river coming off.
0:06:34 > 0:06:36And it looks entirely without life,
0:06:36 > 0:06:41an inhospitable lump of freezing, fresh water floating in sea water.
0:06:42 > 0:06:45It's just a stunning sight.
0:06:45 > 0:06:50I've never seen a single piece of ice that is this big.
0:06:50 > 0:06:52It's an absolutely amazing sight.
0:06:54 > 0:06:58This was the iceberg the team planned to board and explore.
0:06:58 > 0:07:03It was criss-crossed with crevasses, huge cracks and melt rivers,
0:07:03 > 0:07:06and for two years it had been the largest, floating object
0:07:06 > 0:07:07in the Arctic seas.
0:07:09 > 0:07:12It even had a name.
0:07:12 > 0:07:15The Petermann Iceberg.
0:07:17 > 0:07:22Wow! That thing is colossal! I never imagined it would be that big.
0:07:22 > 0:07:24I mean, it makes the ship look like a tiny, little toy!
0:07:24 > 0:07:27Imagine how I felt when that appeared out of the mist.
0:07:27 > 0:07:29It looked like a continent.
0:07:29 > 0:07:32So how massive is it, exactly? Did you measure it?
0:07:32 > 0:07:35For something that size, you need a bit more than a tape measure!
0:07:35 > 0:07:38There's a lot of specialised equipment involved.
0:07:38 > 0:07:41- Do you want to see how we did it? - Course I do! It's incredible!
0:07:43 > 0:07:46As soon as we arrived, it was action stations.
0:07:49 > 0:07:50We've got the funny angles...
0:07:52 > 0:07:55Our first task was to scan the berg.
0:07:55 > 0:07:58The scanning equipment would reveal the iceberg's size
0:07:58 > 0:08:00both above and below water
0:08:00 > 0:08:05but to get accurate results, we needed to sail all the way around it
0:08:05 > 0:08:08and the nearer the ship was to the berg, the better the results.
0:08:12 > 0:08:1515 metres towards the iceberg, if the captain's happy with that.
0:08:15 > 0:08:19The ship's captain was very cautious, and for good reasons.
0:08:19 > 0:08:23Icebergs are amazingly unstable and unpredictable.
0:08:23 > 0:08:26Smaller ones can suddenly roll over and, without warning,
0:08:26 > 0:08:28can completely shatter.
0:08:33 > 0:08:36That's why the expedition team picked the Petermann Iceberg.
0:08:36 > 0:08:41It's big, it's flat and, we hoped, more stable.
0:08:41 > 0:08:44This was especially important when we were sailing
0:08:44 > 0:08:46so close to its edge for the scan.
0:08:49 > 0:08:52So, once they have the scanner in the water, they have to sail
0:08:52 > 0:08:56right around the berg to collect all the information they need, right?
0:08:56 > 0:08:59Right. That's it, Xand, bang on. Then they feed all the data
0:08:59 > 0:09:02into computers, which turn it into images
0:09:02 > 0:09:04that you and I can understand.
0:09:04 > 0:09:06Chris Packham got to grips with the results
0:09:06 > 0:09:08with scientist Richard Bates.
0:09:12 > 0:09:17As well as being a geophysicist, Richard is an imaging expert
0:09:17 > 0:09:20and he has turned the results of the berg scan into a 3D image.
0:09:22 > 0:09:25He found that the bit of the iceberg under the water
0:09:25 > 0:09:29was nine times bigger than the bit above the water.
0:09:29 > 0:09:33The results also enabled Richard to estimate the iceberg's size
0:09:33 > 0:09:37reasonably accurately and the result is amazing.
0:09:38 > 0:09:41OK, so we've measured the circumference.
0:09:41 > 0:09:43It's about 27km around.
0:09:43 > 0:09:46We've measured the thickness all around,
0:09:46 > 0:09:50and we've got an average of about 70, 75 metres of thickness.
0:09:50 > 0:09:53It gives us a volume of about 2 billion metres cubed
0:09:53 > 0:09:55of ice in there.
0:09:55 > 0:09:572 billion metres cubed?!
0:09:59 > 0:10:042 billion metres cubed! That's difficult to get your head around.
0:10:04 > 0:10:07That's roughly the same as 2 billion tonnes in weight.
0:10:07 > 0:10:11That's hard to get your head around, too! This might be easier.
0:10:11 > 0:10:15If you melted it all in the biggest pan ever made, it would be the
0:10:15 > 0:10:18same as 2 trillion litres of water.
0:10:18 > 0:10:22And if that's still too hard, it's enough water to supply
0:10:22 > 0:10:26the whole of the United Kingdom for 200 days.
0:10:26 > 0:10:31That's enough water for every single person in the country. Wow!
0:10:35 > 0:10:36Xand.
0:10:36 > 0:10:37Xand!
0:10:37 > 0:10:40I'm going to have to call a doctor if you don't respond.
0:10:40 > 0:10:42CROWD: You are a doctor!
0:10:42 > 0:10:43Yes, I am. Xand!
0:10:43 > 0:10:45Oh, sorry, Chris.
0:10:45 > 0:10:48I'm just completely gobsmacked by that. I mean, what is a trillion?
0:10:48 > 0:10:50I know it's a lot but how much is it?
0:10:50 > 0:10:53Do you really want to know? It might set you off again.
0:10:53 > 0:10:55Nope, I'll be fine, just hit me with it.
0:10:55 > 0:10:57OK, stick with me.
0:10:57 > 0:10:59Hold the board.
0:10:59 > 0:11:01Now, 1,000 is a one with three zeros, OK?
0:11:03 > 0:11:07A million is a thousand thousands, so that's one with six zeros.
0:11:10 > 0:11:14A billion is a thousand million. That's a one with nine zeros.
0:11:18 > 0:11:21And a trillion is a thousand billions,
0:11:21 > 0:11:24so that's one with 12 zeros behind it.
0:11:28 > 0:11:30And remember,
0:11:30 > 0:11:32we're talking about two of those.
0:11:32 > 0:11:362 trillion litres of water floating around in the ocean, frozen solid.
0:11:36 > 0:11:39No wonder my mind was blown cos it is mind-blowing!
0:11:39 > 0:11:40Can we see more?
0:11:40 > 0:11:42Yes, of course.
0:11:44 > 0:11:47The scan results also revealed something else.
0:11:47 > 0:11:49An unexpected problem.
0:11:49 > 0:11:52The position of the ship related to the position of the iceberg
0:11:52 > 0:11:54seemed to be changing all the time.
0:11:56 > 0:11:59According to your diagram, we're in the middle of the iceberg,
0:11:59 > 0:12:03which can only mean one thing to me and that is that it's moved.
0:12:03 > 0:12:05Exactly.
0:12:05 > 0:12:07It was a shock. The team chose this berg
0:12:07 > 0:12:10because they thought it had gone aground
0:12:10 > 0:12:12and, therefore, it wasn't moving.
0:12:12 > 0:12:15Instead, it looked like the opposite.
0:12:15 > 0:12:17It was on the move.
0:12:17 > 0:12:21We needed to put more equipment onto the actual iceberg to try
0:12:21 > 0:12:25and keep a track of its shifting position but the bigger problem was
0:12:25 > 0:12:30that the skipper, Ragi, had to dock the ship against a moving target.
0:12:30 > 0:12:32HE SPEAKS IN HIS LANGUAGE
0:12:40 > 0:12:44So hang on, the glaciology team chose the Petermann Iceberg
0:12:44 > 0:12:48- because they thought it was grounded and not moving.- That's right.
0:12:48 > 0:12:50- But it is moving.- Yes.
0:12:50 > 0:12:52Whoa, so that must have been difficult to get on.
0:12:52 > 0:12:54Must be hard enough getting on an iceberg
0:12:54 > 0:12:57when it is standing still, let alone when it's moving around.
0:12:57 > 0:13:00- How did you do it? - With a lot of difficulty.
0:13:00 > 0:13:02There's loads of danger from the ice
0:13:02 > 0:13:05and a lot of precision sailing from Ragi, the skipper of the ship.
0:13:05 > 0:13:08Ice isn't the only danger in this part of the world
0:13:08 > 0:13:10but you'll have to wait until next time
0:13:10 > 0:13:12to find out what the other danger was.
0:13:12 > 0:13:15I hate it when you do this! You get me all interested and excited
0:13:15 > 0:13:17and then you tell me I have to wait!
0:13:17 > 0:13:19You're not alone. Everyone else has to wait, too,
0:13:19 > 0:13:22and it's really worth waiting for, I can tell you.
0:13:22 > 0:13:25- Well, can you at least give us a hint?- Erm, OK.
0:13:25 > 0:13:29One of the dangers is furry with big teeth and claws.
0:13:29 > 0:13:30A penguin.
0:13:30 > 0:13:31No, wait. A lion.
0:13:31 > 0:13:34No, Xand. But I'll tell all later,
0:13:34 > 0:13:38so join Xand and me for more stuff that will blow your mind!