Putting science on the map

Back in 2019 the company Dreamworks launched a film abominable about some children and

a Yeti they're trying to save.

Surprisingly for a kid's cartoon it ended up banned in several countries and it's all

thanks to an invisible border.

In one brief scene in the animation there's a map of Asia seen in the background and

over the South China Sea is a nine-dash line.

Those dashes mark China's claim to several island groups in the sea and it's a claim

that many of its neighbours dispute.

Now why the map was included in the film when it wasn't a crucial plot point it doesn't

really matter for the outcome which was that the film ended up being banned in Vietnam,

Malaysia and the Philippines and some movie executives faced a costly reminder of the

power of a map.

I'm Marnie Chesterton from the BBC World Service, this is unexpected elements.

As this is not a show I do alone I have with me an international panel of science journalists.

So in Helsinki, Finland we have editor at large for Grist magazine Tristan Arton, welcome

Tristan.

And in Mexico City getting up horribly early to be with us welcome back to science and

health journalist Katie Silver.

So this is the science show that takes its inspiration from the news and what we do is each

week we look to the headlines, we find a story that jumps out at us and we explore the

surrounding science.

Sometimes we throw an expert in to join the party, we explore the BBC's archive to see

what we can find there, we raid the science journals for a research that may have passed

you by and we all learn a lot.

But it all starts with that one headline, take a listen to this.

You might have heard that old cliche that we know more about the surface of the moon

than we do about the deep sea.

You think about the sea floor and floor implies flat.

You don't always think of it as being this incredibly varied terrain.

Deep ocean trenches, undersea mountains and deep reefs.

It's just so expensive to do deep sea exploration and research, only the wealthiest countries

have access to these kinds of tools.

And one of those wealthy countries is China.

It was recently reported that China is quietly conducting a massive undersea mapping operation

across the Pacific, Indian and Arctic oceans.

Dozens of research vessels and hundreds of sensors are gathering data on marine conditions

and mapping the sea floor.

Now on paper, this is science research, but according to the shipping and satellite data

tracked by Reuters, the ships have been sailing in systematic grids focused on militarily

important waters.

Naval experts have told Reuters that this information would be crucial for deploying submarines

more effectively and potentially waging undersea warfare against the United States.

Katie Tristan, have either of you come across this story?

Katie, I'm going to go to you first because you used to be based in Singapore pretty much

on the doorstep.

Is this something that you've heard about before?

I haven't heard this specific story.

I mean, we talked a lot about US China and I guess the battle there, and we talk about

things like electric vehicles, green tech, and to kind of use scientific advances to make

political advances.

Something we talked a lot about, I haven't personally heard about it.

Have you Tristan?

No, not at all.

And I'm not going to lie.

I kind of actually thought that submarine warfare was a thing from the Cold War.

It's probably because I watched that movie.

Hard for a October in theaters when I was a kid, so I kind of never thought about submarines

again after that.

Yeah, it all seems like it's more north these days, drones and things like that, not under

the sea.

But we're not really here to talk about international relations.

We're here for the science.

And this story has us thinking about the depotions and mapping.

How would you like to take this conversation?

What science do you want to bring to the party?

Well, I'm going to bring hydroacoustics to this party.

Of course.

It's a cool science party here.

So it seems like hydroacoustics are kind of becoming like the big sort of defining technology

for like mapping the undersea world.

That's what I got for you.

Okay.

So by hydroacoustics, you mean like sonar.

So we're back to pinging and submarines and the hunt for red October.

Yeah, sort of like hydroacoustics is a field and sonar is one of the tools in it.

But I want to talk about hydrophones.

Is that just using an underwater microphone?

Well, yeah, you make it sound not very exciting.

No, I mean it's definitely very exciting.

I borrowed one from the BBC's tech department and stuck it in a fjord in Norway.

And it's impressive how much sound carries versus through the air.

Okay.

First, I'd like to hear that.

And second, yes, you're right.

They are just sort of underwater microphones and they detect and record sound waves and

water by converting pressure changes into electrical signals.

And really have been incredibly useful for science.

Any guesses how you do?

Maybe hearing about the change in tides and waves or, you know, tracking various animals

beneath the water and they can kind of, I guess, monitor their populations.

Yeah, I definitely go with that.

I know that scientists track whales using these things, maybe fishermen and, and comms.

Yeah, well, I mean, good guess.

All the guesses.

We've given you all the guesses.

You've got all the guesses.

Where do you want to go with all the guesses, Tristan?

I've got a couple of examples that I can share.

There's a lot of noise that's happening under the waves, like underwater earthquakes, volcanic

explosions, even landslides.

Okay.

And those are the things that cause tsunamis, right?

Yes.

And there are sophisticated systems which monitor seismic activity and sea level changes

to provide warning for tsunamis, but they can still lead to false positives.

And new research using hydrophones is really developing right now and is providing scientists

the ability to get faster or more accurate alerts when one of these events, like happens

in the ocean in the UK, for instance, Cardiff University's great system, which stands

for global real-time early assessment of tsunamis.

Great.

It uses sound waves that travel through the ocean faster than tsunamis themselves.

And that research is sort of indicating that if events happen within essentially like

a thousand kilometers of a hydrophone station, it takes an average of about six minutes

to run an assessment on what's happened.

So they're thinking that the method could really replace traditional warning systems.

That's fascinating stuff.

Anything else?

Yeah.

I got more.

How much time do you get?

I mean, we've got half an hour.

All right.

Well, recently, hydrophones were used off the coast of Brazil to successfully record

the high frequency clicks made by at least three different species of beach whales.

They're considered to be some of the least understood mammals in the world and are the deepest

diving mammals on record, like they reached up to 3,000 meters below the surface.

And why do those whales click?

So researchers think that they're clicking when they're foraging.

So it's essentially like echolocation.

The sound hits objects like prey.

It reflects back telling the whale information like size-shaped distance of what they're looking

at.

And they do this between around 400 meters depth all the way down to that like deep 3,000

meters that they go.

And essentially the hydrophone method shows that acoustic monitoring is a sort of viable

strategy to monitor like really evasive deep sea creatures like these whales.

But you know, generally it's sort of that race for a comprehensive real time acoustic

picture of oceans is intensifying.

Unfortunately, military applications are where we're seeing the most action, but used in

another way like the infrastructure could really be like an important front on understanding

like the least understood part of the planet.

Exactly.

Thank you, Tristan.

It sounds like this is a kind of sonic version of a window onto this mysterious part of

the planet.

We're often being told we know less about the deep oceans than we do about the surface

of the moon.

So Katie, you're up next.

The floor.

And I mean, the whole ocean floor is yours.

So what do you want to talk about?

Yeah, I'm actually going to go even beyond the ocean floor.

So of course, China wants to map the ocean.

But how about mapping a brain?

Now, a lot of people think that we know a lot about how the brain works because we

already do lots of fancy scans and all that sort of thing, but I'm basically here to tell

you just how little we know it.

So it was only a couple of years ago that they first mapped a full brain.

And I'm not even talking yet about a human one.

This was a fruit fly.

The brain is the size of a grain of sand.

And that was an amazing feat of both human engineering and collaboration.

That sounds like an impressive piece of science.

Tell me more.

Basically, our brains, they're made up of neurons connected by synapses to form circuits.

But the big question is how all these circuits connected to explain complex behavior, like

for example, as humans, how interact or how animals fly.

And this field of study, it's called connectomics, how all these circuits combine.

Now, before this research, scientists had mapped the connectome of a ground worm.

But they've only got 302 neurons.

And in 2024, this team managed to map the fruit fly and that has 140,000 neurons, about

50 million synapses.

Now, it's a remarkable feat.

The group behind it is known as fly wire.

And it actually involved researchers from 127 institutions around the world.

They teamed up.

And just how do you go about mapping that many neurons and connections?

It's incredibly complicated.

So first of all, what they did was they sliced the fly brain, which, as I say, the size of

a pinhead, small than a grain of sand into 7,000 incredibly thin pieces using a microscopic

knife.

They then managed to photograph this at the resolution of a nanometer.

Basically, it's a million times smaller than a millimeter.

Then what they did is they needed to identify and map the connections between the neurons,

which they did through AI.

But the problem is, as we're all discovering, AI makes a lot of mistakes.

And in this case, there's about three million mistakes altogether.

So then this team, this consortium of researchers, basically corrected these mistakes.

They even used an online platform so that volunteers could help out to correct some of

these mistakes.

That's brutal work.

Yeah, they say it would have taken a single person that 33 years working alone.

So absolutely a feat of science.

So can this be scaled to humans, or do we sort of like need to move up the chain through

like lizards and mice and stuff first?

Tristan, you've volunteering to have your brain sliced incredibly thin.

Sure.

I mean, I need it right now, but you can have it later.

That's fine with me.

Sure.

Yeah.

Can you imagine how many slices they would need to make if it was 7,000 for a fruit fly?

For me, not many.

Tristan, the less you.

Yeah.

So as you say, they kind of actually are going to be working their way up.

So first of all, we mentioned how they're doing the female fly, or they've done the

female fly.

Next up, they're going to do the male fly.

So it might be one of the first examples in science where women were studied first.

They also then want to do, stand it to the fly's nerve cord.

We're almost there when it comes to zebrafish.

And then the future is mice and even humans.

Now when it comes to humans, they say it could take about 30 years.

And in fact, there's about 86 billion neurons in the human brain.

I'm sure many more in yours, Tristan, and so it does show just how far they're still

is to go.

Thank you, Katie.

I love that ocean floor mapping took us to sonic mapping and then brain mapping, which

is a little bit left-field, but how we roll on this show.

Still to come on the show, life on the ocean floor, or rather, several kilometres beneath

it.

And to be joined by a guest who will explain the incredible party going on down there.

That's off to this.

Hello, this is Georgia here for this week's Unexpected Elements Quiz.

You may think mapping the world's continents would be an easy task, but in fact, there

are many different ways to draw a map of the world.

And they often contradict one another.

The map, most people would recognize, is the Mercator projection.

If you looked at one of these maps, you would see that Finland looks bigger than Zambia.

But in reality, it's the other way around.

What I want to know is what is the actual size difference between the two countries in

land area?

Compared to Finland is Zambia, A, 1.5 times larger, B, 2.2 times larger, or C, 3.1 times larger.

That's how much larger is Zambia compared to Finland, A, 1.5 times larger, B, 2.2 times

larger, or C, 3.1 times larger.

Think it over.

I'll be back soon with the answer.

You're listening to Unexpected Elements from the BBC World Service, and this week we've

been inspired by China's new mission to map the ocean floor, but now it's time to dig

a bit deeper.

A few kilometres deeper, in fact, thousands of metres below the ocean floor, where there's

no light, there's precious little oxygen, and you wouldn't expect any life, well, you'd

be wrong.

The subsurface of the earth is teeming with microbes, and these microbes are unlike anything

you would find above ground.

Here to tell us about them is Karen Lloyd, a microbial biogeochemist at the University

of Southern California, and author of the book Intraterrestrials, discovering the strangest

life on earth.

Welcome, Karen.

Thanks for having me.

I find it extraordinary that there's microbes living under the ocean floor.

How on earth did anyone discover this?

Well, for years, there were a couple of scientists who sort of saw cells under a microscope

from deep sediments, and it's like, well, that could be seawater contamination, because

we know there's lots of microbes in seawater.

I mean, that's the phytoplankton that make the air that we breathe.

It really wasn't until we got really good drilling techniques, where we could be really

sure, no, these are not contaminated with seawater, we're getting good samples.

The big thing was when we became able to sequence their DNA directly, and that's when we

saw, okay, this stuff is pretty different.

This is not just like the stuff floating around in seawater that fell down to the bottom.

This is its own thing.

So how many of these things are there?

There are six times 10 to the 29.

That's too big for my brain to actually...

That's a very specific number, and it's, of course, like, that's a guess, right?

That is an estimation that is made of people who have estimated how many are under the

oceans, and then I'm adding in the amount that's thought to be in the crust of the earth,

and it's an astronomical number.

It's like a thousand to ten thousand times more than the number of stars in the universe.

That's crazy.

And so is that the majority of life then on this planet?

It's definitely the majority of diversity of life on this planet, like in terms of just

how different they are and how many different things there are.

They're definitely winning the diversity game.

And not to be rude to these microbes, but what are they doing there?

They do different things, like different ones do different things, and some of them have

been grown in a laboratory, and when you grow something in a laboratory, then it's like,

okay, I know exactly what's going on.

I can poke it, I can see it move, but there's huge, huge swaths of them where no one's

really gotten them to grow in lab, or if they've grown in somebody's lab, they're growing

so slowly that we can't really do much experimentation on them at all.

And so we kind of have to guess at what they're doing based on the chemistry that we see

around them.

And I mean the fact that they're growing really slowly, that's part of their story, isn't

it?

That's how they survive.

Yeah, as far as we can tell, what we can do in marine sediments is we can calculate

how much energy is being delivered across the entire sea floor to these microbes that they

can use.

If we look at how much energy they're getting per time, per cell, it's 10,000 times lower

than the lowest amount of energy that we know can support life on a laboratory bench.

So it's just extraordinary how little energy is being delivered to these communities.

We can also do the calculation of how much energy it would take to make a new cell, and

it's not enough to really make a new cell with any regular frequency.

So from that, we conclude that they're not really growing in sediments that are hundreds

of thousands of years old.

It appears that it could be possible that these cells live for that long without actually

making a new cell.

They're just really good at hanging out and not doing much.

Right.

So one of the things that I've always loved about trees is that they seem to operate

on a different timescale to us humans, you know, hundreds of years rather than 70.

But with these cells, we're talking another league.

Yeah.

I mean, I can't say I know for sure that an individual cell lives for 100,000 years.

But all my evidence points to the fact that a living cell lives for 100,000 years.

How does that make you feel to know that there's this whole world of ancient slow growers

out there?

I don't think I fully wrapped my brain around it yet.

Theoretically, there could be cells that were around before real good hominoids were walking

there.

So that's an individual cell that's doing its thing, it's metabolizing, it's creating

wastes, and humans have sort of evolved in front of it.

It's crazy.

I was curious about, you said they need just a tiny amount of energy to like power themselves.

But where do they actually get the energy from?

They get it from more unique places than we would ever think about getting energy in our

daily lives.

You know, we do one chemical equation over and over and over again.

We take electrons from food from organic matter, candy bars, whatever we eat, and we take

those electrons and we put them into oxygen.

That's respiration, that's breathing.

But these organisms can breathe so many different things, some of them can breathe carbon dioxide,

which is our waste, and they can take it in and breathe it like it's oxygen.

So the range of different chemistries that are available to them to power them are just

infinite.

So they don't really need much energy, they don't have enough energy to reproduce at anything

like a kind of surface level rate.

I mean, they sound like a halfway house to sort of minerals.

Oh yeah, I know.

They really do.

They blur the lines between biology and geology for sure.

And how deep have they been found?

We've mentioned sort of under the sea floor.

Yeah, we've also looked for them in the crusts as well.

So I believe the deepest ones are around five kilometers deep into the crust, like drilling

in a mine.

But that is not an absolute limit, and it's often not known exactly how deep the water

comes from.

So even if you have like a deep mine, you know, you're pulling water out of the rock walls,

but it could be coming from even deeper.

So that five kilometers number is not like a hard number.

But I was down three kilometers a couple of weeks ago, and they were there.

Just Bragg.

I know.

Well, it's amazing.

Some of these deep mines are amenable to scientists coming in and I'm grateful to them

for doing that.

I was going to ask what the use in knowing more about all this, like how might it help

us humans?

That's a great question.

Part of our big challenge is humans is to deal with our own waste.

We've been pulling carbon in the form of fossil fuels and natural gas out of the subsurface

where these organisms live and putting it into the atmosphere and that's causing us

a lot of problems.

And so there's a lot of motion to capturing some of that carbon and putting it back underground.

And I think that's, it's a smart thing to at least look into doing.

And so when that carbon goes back underground, it's not going to be as fossil fuels.

And we need to monitor the subsurface life because they might be helpful if they convert

it into rock.

That's a big help.

Any more questions for Karen?

Otherwise, I will let her go.

I'm thinking about evolving in front of a cell that doesn't do anything in a situation

or maybe better yet.

I'm actually thinking about like, what are they biting their time for?

What's going to keep me alive?

Yes.

What are they waiting for?

Because you can't just say like, oh, they live forever and never divide and never have

frogyny because like Charles Darwin has to be right.

So they have to have passed these genes along that are the genes that enable them to be super

slow to somebody.

And so they have to be waiting on something.

And so since they hang out for geological time scales, then you know, in my own research,

I've been looking to what geological event are they waiting to have happen.

And so one thing is ice ages.

They come about every 100,000 years or so.

So maybe they're waiting on an ice age to come back or waiting on the slow, tectonic

movements of the plates to sort of crash into each other and push them somewhere.

But they're waiting for a swarm of earthquakes or something.

Well, Karen Lloyd's author of intra-terrestrials discovering the strangest life on Earth.

Thank you so much for coming on to unexpected elements and blowing our brains.

Thank you so much.

Fun conversation.

So the news headline of China's efforts to map the ocean floor has led us to Wales clicks,

flybrains and the most abundant diversity of life on the planet, which turns out to be

in the planet.

Still to come on the show, the most valuable potato-shaped rocks on the sea floor.

Should we leave them there?

This is Unexpected Elements from the BBC World Service.

The science show that's inspired by the news.

I'm Marnie Chastatin in Cardiff in the UK and with me are...

Katie Silver in Mexico City in Mexico and...

Tristan Arton in Helsinki, Finland.

We always like to make space for a story that may have passed us by.

One of the panel brings it.

It's kind of like a show or tell item.

Often I award them totally spurious bonus points if they can relate it to the overall

theme of this show, which this week I should remind you our show is inspired by the Reuters

headline that China has been secretly mapping the ocean floor.

So Tristan, what have you found that slipped under the radar that you need to tell us about?

Well, today I'm bringing you something I've been following closely for the last year.

Deep sea mining.

Okay.

To be clear, you're spurious points.

You're taking all of the spurious points.

I'm taking the spurious points because in the past, I've had to make some stretches.

This is clear.

You've already won.

Congratulations.

When you say deep sea mining, are you going to talk about harvesting sea potatoes or

rather to give them their proper name, those deep sea nodules?

Sea potatoes, yes.

So ocean floors hold vast deposits of critical minerals like cobalt and meganese, nickel, copper,

and they're held in something called a polymetallic nodule, essentially potato-sized rock.

The nodules are found particularly in regions like the Clarian Clipperton zone, which is

a vast abyssal plane and the Pacific Ocean spanning roughly four and a half to six million

square kilometers between Hawaii and Mexico.

And the U.S. says sea bed mining is a national security issue, basically securing dominance

over critical mineral supply chains for defense systems would break China's control of the

critical mineral industry.

I know that some countries, including the U.S. and the Trump administration, they are

on fast track to mining these nodules.

And I think other places have more of a kind of, well, let's leave these alone for the

time being.

But what's America doing?

Well, around this time last year, Trump signed an executive order to accelerate granting

U.S. entities permits for deep sea mining.

So right now, the administration is evaluating nearly 105 million acres for extraction.

That area spans U.S. territories and international waters.

But the move puts the administration up against the international sea bed authority, which

is the international organization created by the UN to regulate and organize and control

all mineral-related activities on the ocean floor.

So essentially, the ISA is responsible for establishing an international framework for

deep sea mining.

And they've been working on those regulations for like almost a decade.

So what Trump is doing is essentially bypassing that framework in order to spur mining.

And this is really where the under the radar stuff comes in.

Last month, the ISA council ended its session without agreeing to a mining code.

And while the international regulatory framework remains unfinished, the legal loophole kind

of allows the U.S. to continue permitting, and it could still allow commercial extraction

to occur.

Right now, the ISA is working to finalize rules by the end of the year, but it looks pretty

tough because even going into negotiations, there were more than like 30 disagreements

on the code.

Okay.

I mentioned that other nations were more or let's wait to see about deep sea mining.

What is the opposition saying?

I guess beyond the proposed regulations, global opposition is growing.

At this point, 40 nations now officially back a moratorium on deep sea mining from the

reporting that we've seen some of the fiercest opposition is really coming from indigenous

peoples in the Pacific who would be directly impacted by operations.

It must also be scientific concerns as well behind why people don't want to do this.

Yes, they're actually almost entirely science-backed.

The bottom of the ocean is super fragile.

It's the least understood ecosystem of the planet, less than 0.001% of the sea floors

been studied.

Some scientists estimate that deep sea mining could cause up to 25 times more damage to global

biodiversity than just land-based mining.

Digital research shows that sediment plumes kicked up by these underwater tractors, which

are like the size of a house, could like severely harm zooplankton, essentially creating

like a domino effect that could like lead to broader, just ecosystem collapse.

And what about the nodules themselves because they are a one-time harvest, right?

Yeah, it's effectively like a one-time extraction.

They only grow millimeter by millimeter over millions of years.

And do we know enough about their actual functions on the sea floor?

Because I know that there was talk that they might generate oxygen.

Yeah, like scientists know that the nodules are like vital habitat for deep sea life,

you know, like sponges and corals and anemones.

A lot of species are only found on or near the nodules.

But yeah, there's this big question about whether they produce something called like dark

oxygen, which is essentially producing oxygen without photosynthesis.

So scientists are kind of looking at this.

I understand that they're debating it as well too, but it's a big question that hasn't

been answered.

And Tristan, is it bad that I really want one of these for my mental piece?

Probably, I would say at least put some guardrails and say that you have to dive to get

it yourself.

You know, you could also take the wholesome option and just like make cookies with different

nuts and chocolates that kind of look like them for an ode, super, super wholesome.

I almost can't believe I just said that actually.

Yeah.

Yeah.

There was two wholesome for you, Tristan.

Absolutely not.

Well, thank you, Tristan, for bringing up polymetallic nodules.

So listeners, should we be harvesting the sea potatoes of the deep sea?

And if not, why not?

The email address for this show is unexpected at bbc.co.uk.

And our WhatsApp number, if you want that, is plus 4, 4, 3, 3, 0, 6, 7, 8, 30, 80.

And any spare sea potatoes you have lying around can be re-homed at unexpected elements,

BBC World Service, Cardiff, CF-104GA.

And we give out those details because we genuinely love it when you get in touch.

So we're going to take a moment to rummage through the postbag, starting with a feature

from week before last, which dumbfounded Jeff in the UK.

So Jeff heard our segment on the auditory puzzle of Green Needle or BrainStorm, in which

and we're going to do this.

So don't worry, everyone gets a chance to hear again, in which we played an audio clip

that can either sound like the words Green Needle or BrainStorm, depending on which word

BrainStorm or Green Needle you're expecting to hear you hear a different thing.

Jeff gave it a try and told us how it went.

I was absolutely blown away by this.

I not only managed to make it be either Green Needle, Green Needle or BrainStorm, BrainStorm.

In the end, I could quite easily make it in the same plane, mean BrainStorm, Green Needle

and Green Needle, BrainStorm and that's why I actually heard and I still can't believe

it.

Thank you very much for a massively interesting show.

Listen to it all the time and I still cannot tell the difference between Marnie Chester

and Caroline Steele.

Wow.

It is hard, it is hard.

I promise if you listen closely, I definitely sound more southern as in I'm actually from

several miles further south than Caroline.

That's probably why we've got the same accent.

Katie, Tristan, do you have voice doppelgangers, either of you?

I do actually.

I used to work in the newsroom in London in the BBC and I had a fellow Australian friend

and no one could ever tell if it was me or her voicing packages.

Well, that just means you get to take the credit for twice as much work.

It looks very efficient.

How about you, Tristan?

It's embarrassing.

So I'll tell you, obviously, a lot of people tell me I sound like Kevin Costner.

Oh, now that you say it.

Yeah, it hurts my feelings.

I do hear it.

Kevin Costner and the generic Australian joining me, Caroline Steele.

So after last week's programme, we also got a lot of interesting emails about your experiences

with migraines.

So triggers, auras, remedies and Chris in the UK writes, as a post script to your recent

feature on migraine auras, I'm red-green colourblind, but I still see brilliant reds and greens

in the auras I experience prior to a migraine attack.

So obviously, my brain isn't colourblind, only my eyes.

Isn't that amazing?

I miss the show.

So I'm not actually sure what the, like, the aurea you're describing as.

I take it.

We don't have migraine sufferers on the panel.

Thankfully not.

No, not particularly.

So it's basically like a light show that your brain puts on as a sort of warm up to having

the most terrible headache.

Yeah, it's part of the migraine attack and it's how some people know that they're going

to happen.

This listener who can't tell the difference between reds and greens from the light actually

coming through his eyes can do in the the lights that he experiences as a migraine auras.

So that's, I think that's amazing.

I'm not, I'm not trying to be cheeky, but how do they know that it's red or green if

they haven't seen that?

That's a really good point.

Chris, I'm actually, I'm actually like legitimately interested, not, not, definitely not trying

to be rude here.

Chris, could you get back in touch with us and tell us when you see brilliant reds and

greens in auras, do they look like reds and greens when you look at say, strawberry

or a green tree?

And if they are different colors to the reds and greens that you're seeing on strawberries

and trees, how do you know that they're reds and greens?

Chris or anyone else color blinds who experiences migraine auras, I feel like that's a very

small percentage of our listenership, do get in touch and tell us.

Talking of getting in touch, I've got a couple of postcards, both of which acknowledge

the fact that I always say, please write to us because I love postcards.

Chris in the UK says, you like postcards so much, I thought I'd send you this one.

Thank you Chris, who has sent me a picture of Hilda Ogden, who's an iconic character from

a Northern UK soap opera called Coronation Street, so thank you for that.

To go from British to the other side of the world, epic postcard, a fold out one of Melbourne,

Australia. And this is from Carl, who writes very much enjoying listening to your show and

often learning something new. I hope you can keep finding new topics to look at.

Keep up the great work, Carl, from the hills of Endeavour.

On that note, what I'm trying to say is, I love postcards.

Thank you for sending them, do send more.

Postal address is Unexpected Elements BBC World Service Cardiff CF-104GA in the UK.

Still to come, flipping poles and flipping problems on the sea floor.

That's all to come after this.

Hello, it's Georgia again, back with the quiz answer.

Earlier, I asked you how much larger is Zambia than Finland in land area,

despite the Mercator Projection showing Finland as bigger.

Is Zambia A 1.5 times larger?

B 2.2 times larger?

Or C 3.1 times larger?

The answer is B. Zambia is 2.2 times larger than Finland.

It has a land area of 723,000 kilometres squared,

compared to Finland's 338,000 kilometres squared.

That's because, by flattening the globe into a two-dimensional rectangle,

the Mercator Projection stretches out the map at the top and bottom.

This makes countries near the equator look smaller than they are,

and countries near the north and south poles bigger.

Were you able to locate the right answer?

If not, maybe next week's quiz will point you in the right direction.

Now, on this show, we love to map out answers to your questions.

Yes, it is time for Ask the Unexpected,

and this week's question comes from Mark.

Katie, do you want to read it out?

Sure, so Mark said, why do the magnetic poles on the sun flip every 11 years,

giving us two 11-year maximum or minimum cycles or 22 years total?

That is a very good question.

And to help us find an answer, we spoke to space weather researcher.

Yes, that's a job.

Dr Edmund Henley at the UK's Met Office.

The sun's cycle changes in strength on an 11-year basis,

and then in direction on a 22-year basis.

The sun's magnetic field gets generated in small amounts

deep inside the core of the sun,

and this gets pulled up to the surface and aggregates together

to become the sun's overall magnetic field.

And the upshot of that is that the sun's overall magnetic field

ends up waxing and waning in strength over time.

There's quite a few physical mechanisms that play,

so one of them is that there's a circulation pattern inside the sun

that's a bit like those that we see at Earth,

where the magnetic field that's coming up from deep inside the sun

comes up near the equator.

And then once it gets through to the surface,

it then gets pulled towards the poles,

where it then sinks down again under the sun's surface.

Okay, so the strength of the sun's overall magnetic field

is waxing and waning over time.

But what other physical mechanisms are happening?

The other one that's important here

is called the Babcock latent mechanism.

So when magnetic field comes up through the surface of the sun,

you end up getting a sun spot

and these end up decaying over time.

But we think that there's some magnetic field

that ends up getting left over after those sun spots have decayed.

And it's that remagnetic field that gets pulled up towards the poles.

And it ends up pointing in the opposite direction

to the magnetic field that's already there.

So it ends up cancelling it out basically

and slowly over time that chips away

that magnetic field until there's nothing left.

And then the sun's overall magnetic field

starts pointing in the other direction.

And that magnetic field in the opposite direction

slowly gets eaten away by the sun spots as well

and that completes the cycle.

And that ends up happening on this 22-year basis.

Okay, so it's 11 years times two.

Thank you, Dr. Edmund Henley.

And thank you, Mark, for the question.

So it's a bit like the Earth's version

of our magnetic North and South poles flipping.

And that is something that happens on average every 450,000 years

and is completely unpredictable.

But when the poles flip on the sun,

it causes more solar flares which, in turn,

trigger more intense aurora displays.

So, Tristan, I think we've talked about this before

because I just think of Finland and I think auroras

because I went there and I saw the Northern lights.

And you haven't really seen anything amazing, have you?

I mean, I've seen them before here,

but they don't make it as a Helsinki very often

and frankly, when they do, I'm asleep.

And it's cold outside.

Also, when I was in the North of Finland

and we all went outside because we had the app

that says aurora watch.

And so you're kind of running outside to go and watch.

Even with a coat on, it's still minus 35 degrees and it's dark.

And what I could see was a smear in the sky.

It didn't look as impressive as the photos

that my camera managed to take.

Katie, have you seen much?

No, I haven't either.

It's very bucket list.

But if you're saying the photos are better, maybe I've seen enough.

I mean, they are cool to see.

I mean, I was quite happy.

But I have a question that wasn't answered.

When is the next flip?

Yeah, the reversal happens.

I think around the peak of the 11-year solar cycle.

So the solar maximum, which from everything I've heard,

is kind of now.

So I think it takes about a year to complete.

So full flip should be happening at the moment.

Peak aurora.

So aurora seekers should be flocking to Finland,

Norway, Sweden, etc.

To see these things, kind of like, now wish.

I mean, everyone should be flocking to Finland.

Anyway, listeners, if you have a question causing your brain to flare

and an internet search isn't helping,

we'd love to try and have a go.

You can email us at unexpectedatbbc.co.uk

or our WhatsApp message is plus 444-330-678

Now, we've talked about ocean floor mining in the context of polymetallic nodules,

and I wanted to take us before we go on another kind of underwater mining.

So with the help of the BBC extensive cavernous archives,

I want to dip a toe into the science and tech of naval warfare.

And here's the BBC World Service news from early March.

The US Defense Secretary Pete Hegseth says a torpedo fired by a US submarine

has sunk an Iranian warship in the Indian Ocean.

In fact, yesterday in the Indian Ocean, and we'll play it on screen there,

an American submarine sunk an Iranian warship.

So that got me thinking about the underwater warfare

that's going on out of sight.

And submarines really are the expensive headline-grabbing pieces of military technology.

But if you look at what's done the most damage over the years,

it's the relatively cheap naval mines or the ROVs, the remote operated vehicles.

So from a year ago, in the BBC Archives, I found a BBC World Service documentary

called The Subsea War. And here's reporter Douglas Fraser laying out the issue.

The sea bed hosts the arteries of the modern economy.

Telecom cables carrying terabytes of data, electricity grid connections,

and cables linking wind turbines. Pipelines bringing oil and gas ashore,

or pumping it between countries to keep our home fires burning.

These assets are so valuable and strategically important to modern life,

the sea bed has become the battleground for a new type of warfare.

So there we go, the sea bed as the battlegrounds, which is why it makes sense that up in

Bergen is the headquarters of the Royal Norwegian Navy, where they shared with Douglas the tech

they used to monitor and map their sea floors.

My name is Tim Orton Standoff. I'm the chief weapons officer of this container system.

So can you describe what we're looking at here?

Right here we have a Norwegian-made Kongsberg AUV, autonomous underwater vehicle.

So we use it for mapping the sea bottom, and we can use that later on to detect difference

or to detect any changes. So we make a baseline of all the cables and everything,

and then we'll be a lot less time-consuming to do a follow-up run,

and then we can see if there is any changes.

Okay, so that's the Norwegian Navy looking out for unusual things on their sea floors,

and they regularly check their feuds, where incredibly just had to share this.

They've got telecom cables that have been laid over some legacy mines that were laid

before the Second World War, so here's Morton showing images of these two worlds colliding.

So this is a mixture of the seabed from its sonar.

I actually have taken pictures of British Mark 17 mine, who was laid pre-war

like in 1939, and on top of it you can see there is a fiber cable on it.

So the cable goes right across a British mine, and that could still be live?

There is explosives in it, but it's not live. So all the electronics and all firing devices

is gone, but the explosives are still there.

It doesn't pull any threat to the cable.

It might do, but it's deep, so it's stable, and it's been there for 85 years, so.

So when they laid the cable, were they aware that this was a British minefield from 85 years ago?

I would say probably not.

Wow, isn't that incredible?

He's very laid back about the fact that some of Norway's internet is essentially just

lying on top of a bomb, and this brings me back to these mines just like land mines, which were

banned by the Ottawa Treaty in 1997. Naval mines are cheap to deploy, but they are much more

expensive and a real pain to get rid of. So deploy with the caution.

Since I have you, Tristan and Katie, do you know who does the mine clearing?

And they say no idea. The US has a specially trained unit of dolphins that they use for

mine clearing, and they said back in 2012 that they were going to phase these dolphins out and

replace them with robots, essentially. But I think as of 2023, they were still using them,

so they were just waiting for the tech to come back online. I can't find anything more recent

than that. And there's no, I assume the dolphin dies.

No, neither mine, no, they report, they locate and they report back.

That's incredible. I'm just trying to imagine how they're relating the information back,

which just seems silly, and my imagination.

Well, I'm reading, so they use Eka location to take us back to Tristan to detect where the

mines are, and then they signal it to a handler. So they locate the mine and it returns to its

handler, communicates the finding, and often, often by pressing a small paddle or boy device,

and the dolphin is then guided to release a marker boy or a transponder directly onto or near the

mine. And then Navy personnel actually go and detonate the mine. Wow. But that's a proper tag

team effort. That's great. I mean, they're very well-trained. Yeah.

And they use Eka location. I mean, as long as they get the retirement afterwards, this is what I,

you know, the last show I was on, you guys told me that the medical leeches go to live on a farm

effort. So I want to make sure that's the same, same situation. Yeah, that was lies, but this,

yeah, I promise you.

So, there we go. Who knew that about dolphins? All of which brings us to the end of a science show

that has been scraping the bottom of the ocean. For stories of mining and telecoms, polymetallic

potato-sized rocks and hydroacoustics all inspired by a Reuters story about China ramping up

its mapping of the sea floor. That's asked pretty much out of time, so it just remains for me to

map our way to the end of the program, which should involve thanking our excellent panel.

In Helsinki, Finland, bringing us tales of underwater acoustics. Thank you, Tristan Arton.

Oh, oh wow.

And in Mexico City, bringing us the mapping of the flybrain, thank you, Katie Silver.

Thanks, Manny, as a love for Oxima. I'm Manny Chesterton. The producer was Ella Hubba with Lucy Davis

and Georgia Christie, technical production by Gwyn Jones. Join us next week for more unexpected elements.