Wind farms, hair growth and inherited fears

This is a Triple J podcast.

Hi, I'm Bec Charlwood, and welcome to this week's episode of Science with Dr. Carl.

This week, we'll be answering the questions, why does your Bluetooth speaker glitch when

you use the microwave?

Can your fears be genetically passed down?

And why does hair grow here, but not there?

Let's jump in.

It is Science Hour with Dr. Carl.

He joins me in the studio now.

How are you doing?

Pitchy keen.

I'm very excited.

My 48th book is out.

It's an ABC book, and it's called A Periodic Tale, My Science Memoir.

And the trouble is that instead of saying things, hey, did you know that you can make

really good microphones out of spider web, or trees talk to each other via the underground,

by the world, the wood wide web, or all black holes have the same size, which is zero.

Instead, I've written a book, which is kind of like, I've written a book about me telling

you how wonderful I am.

Buy the book, and there'll be an exam.

I'll tell you how wonderful I am.

I'm not expecting you to get 80% or else.

No, no.

But it is a book.

I'm doing shows at Bundaberg on Monday the 9th.

So do come along to Bundaberg.

And then you can find out how to get there by going to drcarl.com, D-R-K-A-R-L.com.

And then on Wednesday the 11th in Brisbane, Thursday the 12th in somewhere, Sunshine Coast.

And then Sydney Sunday, Tuesday the 17th, and then Adelaide Monday the 23rd.

And the basic thing is I've tried to write a book that's interesting, and it doesn't

fall, yeah, driven by generosity, curiosity, and what else, optimism.

And I've tried not to fall into the category of, I've read, I've read one autobiography.

Do you read autobiographies much?

Yes, yes.

Have you read, do you read the one by Flea, yeah, from Little Hot Chili Peppers?

No, I haven't read Flea's yet.

I'm currently in the middle of Viv Albertine's from The Slits.

Oh, what's that autobiography?

Viv Albertine from the punk band The Slits.

Is he a nice person?

Um, no, but that makes for a great memoir, I think.

Yeah, well, so with Flea.

So I don't know what yours is going to be like, because you're a delight.

No, I'm kidding.

Okay, so with Flea, he has incredible adventures.

Like, okay, so I accidentally, while I was high on methamphetamines, wandered into the

police shop with another five kilograms of heroin, and amazingly I got out.

And so there's all these terribly exciting story page turners, but you're thinking, if

I was a cab driver or a barista.

He'd be mean to me.

And so there's no sort of higher moral.

And then there's other autobiographies that fall into the straight chronological, I had

a cup of coffee, I had a cup of tea, I went to the toilet.

And there's others that are name dropping.

Well, as Prince Charles said to me while we were listening to Madonna, you know, I really

don't think that we should come to the party, you know, in that category.

And then there's the other category of, I've had a whole bunch of really bad relationships.

So I've tried to be positive and tell stories.

That'd be my memoir, just a bunch of breakups and sob stories.

Yeah.

I've done various things in my career, like when I was a roadie for Bo Diddley and Chuck

Berry once.

I learned so much about you every single time I tuned into Science Hour.

And it makes sense because this book, I'm holding it in my hands.

It's heavy.

It's thick.

And it's got pictures of me on the inside.

On the back, there's pictures of me wearing disarmingly high pants with the jumper tucked

into the trousers.

That's, I try not to do that look anymore.

My family advised me against that.

It's still very appealing.

You look absolutely stunning on there.

Oh, come on.

You're too kind.

We've got some callers.

Are you ready for some questions?

We live for the audience.

All right.

We've got Mike here from Port Macquarie.

Mike, Dr. Mike, my apologies for getting your formal title.

What's your question for Dr. Carl?

Hi, doctors.

I've got an interesting question for you.

Every time my kids and I listen to a lot of music, and when we have our Bluetooth speaker

playing, and then somebody uses the microwave, the speaker glitches.

And it doesn't really matter where we put the speaker.

But just trying to figure out what's going on there, and is it safe to, you know, does

it assign the microwaves dodgy or something like that, so if you can help us out, that

would be very useful.

Okay.

So firstly, a tiny amount of microwave energy does escape from the microwave, but it's certainly

not enough to be harmful.

And by harmful, the harm that it does is make you warm.

It does not cause cancer.

So we've had yet another report come out summarizing 20 years.

Showing in this particular case that mobile phones do not cause cancer.

Now, what's happening is that there's a coincidence.

The number is 2.5 roughly gigahertz, and both your Bluetooth and your Wi-Fi and your microwave

all work close to this frequency.

Now, with your Bluetooth, they're very clear about what they're doing, and they've got

some very clearly defined frequencies, and so the frequencies that it works on are really

exact, around 2.5 something something, and at a slightly different bunch of frequencies

are the ones for the Wi-Fi, and they're clearly defined.

Now, the microwave is not made to the same degree of precision, so it sort of blasts

out a whole bunch of things, and a small amount of it can leak out.

So I think you would find that if you were to, now hang on, with the Bluetooth, are you

using Bluetooth to play music, or is it Wi-Fi to play music?

Um.

Interesting question.

It's from Spotify, and it'll be, you know, beaming from the laptop to the Bluetooth speaker.

Ah.

Do you have a home Wi-Fi network with speakers that run on Wi-Fi around the house, or is

it just purely...

No.

Sorry.

Just a single Bluetooth speaker.

Okay.

So if it's a single Bluetooth speaker, I think what you would find is that maybe chuck a

big glass of water, and chuck it in the microwave, and then take the laptop and put it in the

microwave.

And then you would have the laptop and the speaker, and have them really close to each

other, and have them really close to the microwave, and then the further away you go, the weaker

the interference should become.

Now, with Wi-Fi, you can, by going into the settings, alter the frequencies that you work

on.

There's a whole bunch of higher and lower frequencies, and you can try and juggle them

to get away from the bad frequencies that cause the interference.

I don't know if that availability is there on Bluetooth.

If somebody is skilled as an entrepreneur...

If you're an IT officer, if you can advise us whether Bluetooth speakers can be tuned,

if you go into the firmware, to work on slightly different frequencies, please ring in.

What's the magic number, Dr. Beck?

0-4-3-9-7-5-7-triple-5.

Yoo-hoo.

Ring now, and you get a free set of steak knives.

Disclaimer, we do not give away steak knives on the ABC.

Okay, we don't.

Okay.

So, Mike, hang in there for that, and also try the forum on the internet called Whirlpool.

It's an Australian forum, and ask your question there.

And they would know whether you can do something by going to the firmware of your speaker

and retuning it slightly.

Very cool.

Thank you very much, Doctor.

Thank you so much, Dr. Mike.

We've got Dr. Candice now.

You are from Gippsland.

You've had some storms up there recently, which have been causing some bizarre behaviour.

What's your question for Dr. Carl?

Morning, Doctors.

My question is involving our local murder of crows,

who haven't been themselves since the storm, actually.

So they've, like, swapped trees.

They're, like, seriously fighting with each other, taking swipes out of each other,

and have been cawing, like, cawing non-stop for a couple of days.

So we were just trying to figure out if it might be, like, mourning one of their members

or if it's, like, territorial, because they're not normally like this at all.

Are the winds still going at the moment?

A little bit.

Okay.

Now, do you remember the story of Ulysses, the Greek guy,

and floating around the Mediterranean having adventures?

You might have to refresh me on that one.

So Ulysses, a two-and-a-half-thousand-year-old,

and at some stage, King Aeolus gives him a bag of winds.

Okay, it's a fairy tale.

King of the fancy mayonnaise.

So open the bag when you want to get some winds to bring you back home after your journeys,

he says to young Ulysses.

And Ulysses, being impatient, opens the bag straight away.

And then he gets blown around the Mediterranean and has these adventures,

and so we have the concept of Aeolian winds, especially windy areas.

So different parts of the world.

There's California, have the Santa Ana wind, which is hot and dry,

and makes the bushfires worse, and also, just to make things worse, carries a fungus.

You have the Mistral in France, where you've got two rivers coming together,

and they combine to make a really cold breeze come down.

And then over in Sicily, on the top end of the Mediterranean,

you get sand being brought across from the Sahara on the bottom side of the Mediterranean.

So you've got the Mediterranean about 4,000 kilometres across,

and underneath you've got Africa, on top you've got Europe,

and the sand blows across, and it's hot and dry, and it's gritty, and it's got a negative charge.

So there's this long history of winds influencing people's behaviour,

and I think it kind of falls into not so much scientific with regard to ionisation,

that's kind of hippie bulldust, or pressure changes, too small to be measured,

but more in the category of it's really annoying being in the wind

because things are moving unpredictably,

and there's dust blowing.

There's dust blowing into my face, so I'm going to feel annoyed.

Going to the crows.

Do crows have the same thing that many primary school teachers talk about with their students?

Don't know.

So it could be, as you wisely suggested, they're mourning the loss of one,

or that they're affected by the wind, so we need an ornithologist to ring in.

And what's the magic number, Dr Beck?

0-4-3-9-7-5-7-triple-5.

Someone on the text line also saying, how does Dr Karl know everything?

But the text line number, because that's my one job,

and I get to feel important, okay?

Candice, does that answer your question?

Yeah, thank you.

Partly.

Partly, yes.

And I do like the way that you've started thinking scientifically,

coming up with possible conjectures as to what might be the cause,

and the idea that a crow might have died in their mourning,

that fits in, because it could have been there was a baby crow

that got blown out by the winds and plummeted before their wings had grown,

or an eagle, I don't know, but we'll know.

We'll know.

Empathy for the crows out there.

Love it.

Thank you so much, Dr Candice.

We've also got Dr Corey on the line with a culinary question.

Dr Corey, what's your question for Dr Karl?

Morning, doctors.

I've got a food question.

What have we got for you?

Why do some foods, you know, such as garlic and onions and fish

and cheeses, meats, I guess,

why do they smell so bad when they're uncooked?

And when you cook them, they smell really nice,

and particularly when you're eating them, they taste nice.

We've evolved into our last stage about 200,000 years ago,

but about 2 million years ago, we started inventing tools and fire,

and there are chemicals in the foods.

So going through the foods you mentioned, fish, fresh fish, have no smell.

The chemical involved that makes them smell bad,

is called trimethyl amine,

and there are some humans who actually are born with a genetic condition

where they smell like bad fish.

It's called trimethyl aminuria,

and it's discussed in the Vedas and ancient Hindu medical texts

about 2,500 years ago.

Now, some foods, it doesn't matter whether you cook them or not.

Apple, you can eat it raw, or you can cook it and you can eat it.

Potato, mate, no way can you eat it raw.

You eat a raw potato.

So think about six people holding hands in a ring

and turning six people into carbon atoms.

So that's your glucose molecule, six atoms in a ring.

And believe it or not, depending on which way an oxygen or a hydroxide comes off,

there's one position where if it comes off at this angle, you can eat it raw,

but if it comes off at the other angle, you can't, and so that's a potato.

So we've been conditioned that if you cook potatoes,

you will be able to digest it.

And then if you cook meat, oh, my God, you are getting so much protein

and you're getting B12, and you could kind of live off meat for a little while

before you begin to suffer nutritional deficiencies.

So we've been evolved over the last 200,000 years.

Cook the meat, you'll live longer.

Don't cook the meat.

It's a kind of a conditioning to your brain that...

Yeah, so it's been sort of passed down and taught from generation to generation.

Unlike octopuses, because I'm going to bring the mood down,

every octopus is an orphan.

Oh, the saddest fact.

I know, they're so intelligent.

Imagine that they can use tools and stuff.

If only they could have passed knowledge from one generation to the other,

they could take over the world and the world would be a better place.

And I welcome our octopus overlords taking over sooner rather than later.

And they smell when they die until you cook them, so...

They are delicious.

More sad but informative news.

Oh, okay, yes.

Yeah, very good.

Thank you so much, Dr.

Dr. Corey.

Can I do a quick shout-out?

Like the other caller, I was on down in Gippsland too,

and the joint's been annihilated by the storm,

so a big shout-out to all the SES, CHI workers, CFA,

and all the emergency workers involved in the cleanup.

We're getting a lot of questions.

We talked about why different foods smell different after they've been cooked.

A lot of people texting in saying that they eat raw potato

and want to know if there's something wrong with that.

You will probably get a tiny amount of nutrition,

but not as much as if you cooked it.

And almost certainly, based on a long history of having potatoes,

it won't cause any bad effects.

So it might be just fibre.

There might be some minor benefits.

We discovered potatoes with the Spaniards going into South America,

and it turns out that the value of the annual potato crop worldwide

is more than the value of all the gold that they took out.

And the reason...

And secondly, the reason...

There are so many Irish people around the west parts of the world

is that the British were doing bad things to the Irish,

plus they had, out of the 14,000 or so different varieties of potato,

two, not 2,002,

and both of them were subject to being attacked by a certain mould.

And so you end up with the population of Ireland dropping by more than half

and didn't get back to where it was for over a century.

It was a terrible thing,

and many people starved to death during the Irish famines.

It was partially due to the potato

and also the bad practices of the English at the time.

There we go.

All the potato facts that you could need or want.

It's okay to eat them.

You just won't get as many nutrients.

We also have our first question in this segment.

Dr Emily is on the line.

Dr Emily, what's your question?

Hi, doctors.

So my question's about something I saw recently in relation to genetics.

So I'm wondering whether trauma or fears can be passed on,

passed down genetically to children in the sense of on a cellular level,

not on a nurture basis where they've learnt to be afraid of something

because of their parents or their parents had a car accident, for example,

so they're afraid of cars.

I'm sort of wondering if there's the possibility that, yeah,

trauma or an intense fear or even an intense love

and really good reaction to something can be passed down genetically to kids.

Some of it can be.

We've got hard proof.

And the other?

The softer side of things like loving or disliking, we have less proof.

So you've got the DNA and the molecule is shaped like a ladder.

It's about two or three metres long.

It's got three billion rungs.

And one of the great discoveries of the 20th century was that any three of these rungs

tell the biological machinery in the cell to make an amino acid

and you string amino acids together, you get a protein,

you've got enough proteins, you've got insulin, you've got a human being.

So it's all manufactured.

So you've got this, it's like an instruction manual that's read.

Now, here's the trick.

Certain types of trauma have been proven to alter how it's read.

So the DNA still stays the same.

So the person has the same DNA, but now groups called methyl, CH3 and other things,

they latch onto parts of the DNA due to trauma and they stop it being read.

So here's the example.

Second World War, the Allies re-invade.

Nazi Europe, they head for Holland and the Dutch rise up against the Nazi overlords

to try and help the incoming Allies, but the Allies don't get to a certain bridge.

There's a movie about it called A Bridge Too Far.

They don't get to the bridge, they don't get there.

The Nazis still control Holland.

They then punish the locals by starving them to death.

A lot of people die.

A lot of women die.

A lot of pregnant women die, but a few pregnant women manage to have some food

and survive.

And of course...

Of course, as you would expect, their babies are born small.

Now, here's the kicker.

When their babies grow up in full 100% post-World War II nutrition, they're small.

And then when their babies grow up, they're small.

So when they went looking, they found that in the women who had survived the starvation,

bits had been added onto their DNA that said, read this or don't read this.

If you want to make a baby, make it a small one and we're kind of thinking there's not

going to be much food around.

A smaller baby eats less than a big baby.

So we've definitely proven it with regard to various starvation, famine events in Holland

and in Sweden.

When it gets onto things like trauma, like you look at the Civil War in America,

that was the 1850s, survivors, and their children are brought up differently.

But if you survive a war, normally you're not as well off as you are before and you

don't have as much food.

So there's a whole lot of softer stuff.

So maybe some emotions can go through.

So look up epigenetics in Wikipedia, E-P-I, genetics, and have a good long read and that'll

tell you the latest research, which I don't know.

Does that help?

No, that's awesome.

Thank you.

Thanks for all that.

That's great.

Thanks, Dr. Emily.

That might explain why I was born with a vendetta against my next-door neighbor for no reason.

Oh, so it's run down the evolution.

Came from my mother.

Ah.

Okay, we won't mention any names.

No, no.

No, absolutely not.

We've got another doctor on the line.

Dr. Pat.

What's your question for Dr. Carl?

I have a two-part question about our evolution.

How long did it take to reach our level of human from what it was as a chimp?

And is there any cause to believe that there'll be another major evolutionary period for us

or have we stunted our chances with what we've done to our environment and our diets?

The first answer with regard to the environment and diet.

Well, forget that.

I won't go straight for the chimp.

And you're 100% right.

So, seven million years ago, there were all these two-legged animals in Africa and there

were the chimps.

There was a creature that would become the line that led to the chimps and the bonobos.

The bonobos are the ones who have sex all the time, apparently.

And then there was a split and there was another line that led to us.

We were on that separate line.

And if you go looking Wikipedia, look up Lucy, L-U-C-Y, who was a two-legged creature that

was the first one that we know of back then, seven million years ago, and she was about

the height of a, when fully grown, of an eight-year-old child, but had hips that could walk rather

than hips that had to stay in the trees.

And so, she was mostly, that line, were mostly walking around on the land and their brain

grew a bit bigger.

They had their hands.

They had their thumbs.

They were sort of doing stuff.

But two million years ago, you asked about the timeline.

The big change happened.

The big change happened when we had, firstly, a mutation that we'd lost all of our body

hair.

Now, it turns out that hair's made of protein.

And there was another mutation that allowed this protein to go into the brain.

So, the big change two million years ago was that our brains began to get bigger and bigger

and bigger.

And so, we invented fire and tools.

And so, we then went through various stages.

About 800,000 years ago, there was Homo heidelbergensis, who had a brain a bit smaller than ours, but

by looking at the inside.

The skull cavity and the dents created by the brain, we are very confident they had

language.

And 200,000 years ago, we turned up.

And we haven't changed much since then.

We evolved the ability to have milk as adults, 6,500 years ago in Hungary, and following

mutations on the same theme in the Middle East and in Africa.

But only one-third of the world can have a lot of milk as an adult, two-thirds can't.

Are we still evolving?

Yes.

Is the environment making it worse for us or not?

Well, we're actually changing our own evolution right now by having, we're genetically modifying

certain babies who are born with a disease called spinal muscular atrophy, where they

can't make a protein to control their muscles, and they normally die in the first year of

life.

And so, my brother-in-law is an anaesthetist, and he's been part of this.

And what you do is you get an adenovirus, which is a virus that's really good at crossing

into cells.

So, we're doing genetic mutation.

We then scoop the guts out.

We put it in the DNA that says, make this protein, and then you inject it into the spinal

fluid of babies.

This is not the sort of thing you do at home after looking up how to do it on YouTube.

You need maybe 10 years of training.

And so, he does this, and then the babies, instead of dying at the age of one, they live

a normal life.

We've genetically modified them.

So, we are in a position now where we can do genetic modifications.

We've genetically modified in 2021 a man who can...

Now, not have to inject himself with insulin.

And this treatment will spread around the world.

It cost 20 scientists, no, 15 scientists, 20 years and $50 million.

So, we are in a position where we are genetically modifying ourselves, and hopefully, we'll

all end up with immortality, with a healthy 18 to 25-year-old body, which will live in

for 500 to 5,000 years, and we'll have fixed climate change as well, and we'll all be happy

and have unicorn parties.

Great question from Dr. Pat there.

Thank you so much.

We've got Dr. Anton.

Dr. Anton, what's your question?

Yes, good morning or afternoon, whatever it is, doctors.

My question is about sitting down to take a poo, so I apologize in advance for that.

No, very relatable.

Very relatable.

And by the way, it's not just terrorists and murderers that go to the toilet to defecate.

Regular people have been known to do it as well.

I'm going to come out right now as very brave and say, yes, I have defecated.

I will join you.

I have at least once in my life as well.

Oh, you're making it more invulnerable.

Dr. Anton.

Yeah, look, I have to admit that I have done it a couple of times myself.

So what was the situation then?

What's happening there?

Okay, well, I think about this every single time.

I just wonder why, when one sits down to defecate, you would normally urinate, then you would

defecate, and then you urinate again.

And my question is, why isn't the bladder emptied on the first piss, and is there a

physiological purpose behind the second piss?

There's no physiological purpose.

It's an accident.

And what you're looking at is a phenomenon called residual volume.

Now, I'm guessing from your name that you are a male.

Good guess.

Yeah, didn't go to medical school for nothing, mate.

Anyway, so what happens, it's thought to be slightly more common in males than females.

So you have a couple of systems that run your body automatically.

One of them is called the parasympathetic nervous system.

And it controls being relaxed after a meal, and your blood flow to your gut increases,

and you urinate, and you defecate under that.

Now, looking at the bladder alone, think of, are you familiar with the musical instrument

called a piano accordion, where it can sort of expand and contract?

It's got these sort of bellows type thing.

Are you familiar with that?

I am.

Yeah, okay.

So in your bladder, it can be like really small, like the size of a small fruit, but

it's got piano accordions.

It's got piano accordion-like folds in the wall.

And so it'll stretch and stretch and stretch and hold up to a litre.

Oh, okay, 700 mils for a male, maybe 500 for a female.

I forget the exact figures.

That's kind of the ballpark.

So when you have been overnight in bed, there's a lot of stuff in your bladder, and so there's

a big drive.

You know, like when many of the piano accordion folds are stretched open, there's a drive

to urinate, urinate.

So you'll start urinating, and then they'll collapse down, and then the nerves don't tell

the parasympathetic system, we've got to keep going.

They say, oh, look, we're not feeling any more stretch.

So you stop the urination because there's another drive from your bowel.

It's saying, I want to get out of here.

And so that gets out, and then once that's calmed down, then the remaining stretched

endings in your bladder say, what about me?

And then...

Then you urinate the last bit out.

But the concept is residual volume, and being a male, the anatomy was not designed as nicely

as in females.

So unfortunately, most males, like you and me, we have prostate cancer, but it's a very

slow-growing cancer, and we'll die of something else before we die of prostate cancer.

But part of that is that the prostate swells, and it pushes its way into the bladder, and

it leaves areas that don't automatically...

It doesn't automatically flow from the bottom.

So it's not all down.

You've got to sort of move around and jiggle to get the residual volume out of certain

areas.

We've got Dr. Luke on the line.

What's your question for Dr. Carl?

G'day, doctors.

My question is just in regards to offshore wind turbines.

With taking energy out of the wind, because energy is either...

It's not created nor destroyed, just transferred.

Will we start to lose...

Some of the cooling effects of the wind, or how many turbines do you think it might take

before that starts to happen?

Oh, okay.

So if you read the book Disturb the Universe by Freeman Dyson, by the time you get to the

end of it, you'll think everything I do disturbs the universe.

Secondly, I'm a proud grandparent of two young babies who...

And I've been pooed on by both of them through their nappies onto me, and the bottom line

is that at the end of a year...

You've got this absolutely gorgeous baby, and they just smell so nice, you want to just

cover them in Vegemite and eat them all, or whatever.

You just love them so much, and they're so beautiful.

What you don't see is a massive amount of disorder behind, and it'd be probably a few

cubic metres of poo in nappies.

We know, with us for a while doing minnows, I was the person in charge of washing the

poo off the nappies, and we got a little hose on the bathroom, all that sort of stuff.

So the point is you're always causing problems.

So with regard to wind turbines, yes, there will be problems, but in scale, they're microscopic.

The amount of heat disturbance is so minuscule compared to what global warming is doing to

us each day.

Right now, we've got carbon dioxide acting like a one-way valve, trapping sunlight.

So the heat of global warming comes not from burning the fossil fuels, but from the trapped

sunlight.

How much is it each day?

600,000 Hiroshima bombs per day.

So if you add up all of the heat effects from the warming up turbine generators across the

whole world, it might add up to a 10,000th or a 100,000th of a single nuclear weapon

per year.

But we're putting in 600,000 every day, just 600,000 Hiroshima bombs of heat per day.

So yes, there will be effects, but they're so, so minor compared to...

So we should just leave all atoms of carbon in the ground and gradually things will get

better.

I'm very optimistic.

So if you see a bunch of wind turbines popping up around where you live, you don't need to

be concerned about all of a sudden it's going to...

You need to buy a higher sunscreen and, you know, buy some more bikinis to wear around

the place because it's going to get hot.

And some politicians who said that it's been proven that they kill whales, to put it delicately,

they were stretching the truth a little.

Oh, how does that work?

How does that work?

How does it relate to whales?

Oh, wind turbines at sea have been claimed to kill whales.

And if you follow the trail back, you end up at a big old fossil fuel company.

So the first time I ran across the concept of global warming was probably before you

were born in 1973.

Yeah, a little bit before.

When all the...

Munich Re, the world's largest insurance company in the whole world, said, we've got weather

records going back four centuries.

We've been providing insurance for four centuries.

We're seeing stuff and we're relating.

We're relating it directly to climate change.

They call it global warming.

And in 1973, the world's biggest re-insurance company started increasing the premiums.

In 1982, the fossil fuel companies said global warming is real and this is what we expect

to see by the year 2020 if we keep on doing business the way we were.

And in 1990, all the scientists said it's real.

But also in 1990, the fossil fuel companies denied it and started denying it at the rate

of $1 billion per year in lies.

And you can't blame them if you tell the same lie over and over again.

For a third of a century, some people will believe it.

It's going to get around.

Oh, well, thank you so much for your question, Dr. Luke.

We've got Dr. Jamie from Brisbane.

What's your question?

Hi.

I have found this personal anecdote first just to start it off and you'll kind of understand.

When I have my weekly everything shower that the girlies will understand, I always notice

the hair on the bottom half of my lower leg grows faster than the top leg.

Like, faster.

Faster and longer towards the ankle than it is shorter at the knee.

I don't understand.

Is it like blood flow?

You are not alone.

How does that apply to the whole body?

Jamie, I have the same thing.

There are parts of my body that grow faster.

It's weird, right?

Let me get it straight.

So you each have a leg.

The leg extends from the hip to the knee to the ankle.

And in the area between the knee and the ankle, we're looking in the, you're saying in the

lower part of your lower leg, the hair grows faster than in the upper part of your lower

leg.

Between the knee and the ankle?

Yes.

And let me just check.

We have a sample size of two.

Agreeing?

Yes.

That's not bad.

That is correct.

I mean, on one hand, the plural of anecdote is anecdotes, not data.

But on the other hand, it's interesting.

So firstly, if you look overall at hair or look at nails, nails grow at fingernails at

three millimeters a month, toenails at one and a half.

But they reach their maximum rate of growth.

We've been able to track this easily.

They're in their 20s and they begin to slow down after that for various reasons, including

sometimes Raynaud's phenomenon, which is a decreased blood flow.

Hair is very variable.

You've got between six and 12 millimeters a month.

And so it could well be that in one part, you're having it grow at the high rate and

another part at the low rate.

Now, you could be winning a prize here, Jamie.

Have you been taking photographs and measuring it and writing it down and documenting this?

No.

Oh, you're so close.

Oh, okay.

But on the other hand, I can see where you're coming from because you have to do the shavy

thing.

You think, oh, it's bigger there than this.

The answer is I'm reckoning that it's local effects and I'll just stop right there and

I don't know what they are.

We'd need either a dermatologist because they own hair.

They call hair a skin appendage to ring in.

And the magic number is?

043-975-7555.

Because I don't know.

But I'm beginning to think that there's something there.

I'm going to start checking around in a gentle way with females I happen to run across without

trying to be too invasive and rude.

Maybe I'll get some advice on how to do this without being rude.

Find the politest way to say, hey, can I see your legs?

It's for science.

That's a start.

I want the Mark II version.

How would that apply to the rest of your body?

Sorry.

I'm so sorry.

How would that apply to the rest of your body?

Arm hair grows less than leg hair or chest hair doesn't grow at all.

How would that apply to the rest of the body?

I thought it was something to do with oxygen, more blood flow to some areas.

One thing I do know relates to a hormone called testosterone.

So both men and women make male and female sex hormones.

And then women, of course, make testosterone like men make estrogen.

But the women make more estrogen.

So getting back to the testosterone that women make, they make different types of testosterone.

And then it can act on hair follicles in different parts of the body to different degrees.

Because some hair follicles have got different receptors for the different types of testosterone.

So it's sort of genetically wired in that this will grow faster than that.

So I'm out of my depth here.

I don't know whether it's testosterone that drives female scalp hair or not.

I'm sorry.

I failed you.

I saw a real live version of this.

Oh, yeah?

And this is just a single experience.

But I had a friend of mine transition from male to female.

And when she was male presenting before she took the hormones,

she was nearly completely bald.

But once she started taking the estrogen, all of her hair grew back.

Ah, so it may well be a hormonal thing which varies with age and other factors as well.

Oh, man, it's complicated.

It's complicated.

Well, thank you so much for your very beautiful, complex question, Dr. Jamie.

I think our final question, Dr. Daniel, what's your question for us?

Hey, doctors.

I have a question about ships and ocean levels.

If we were to remove all the ships, all of the boats somehow, miraculously, all at the same time,

would it have a dramatic effect on the water level?

Would it drop, you know, a fair way?

It would drop.

It would definitely drop.

So roughly speaking, we have 2 billion tonnes of ships,

that's just the empty weight of the ships, in the water at any given time.

By the way, more than half of the load carried by ships across the world,

is fossil fuels, from here to there.

And if we went totally renewable, we wouldn't have that.

If you were to remove that 2 billion tonnes of shipping from the oceans,

the ocean level would drop by roughly one-fifth of the thickness of a human hair.

A human hair is about 50 to 70 microns in thickness.

A micron is a millionth of a metre.

So the oceans would drop.

The oceans would drop by 12 microns,

but we're melting close to a billion tonnes of ice each year.

And so in that same day, the ocean level would go up by 9 microns.

And so you'd have...

Oh no, sorry, it's the other way around.

You would drop by 9 microns, but we're melting enough to give you 12 microns.

So by around two-thirds of the way through the day,

you would have recovered the loss from the melting ice.

So the oceans are rising, and it varies around the world,

depending on local gravity.

Gravity and subfloor.

So the answer to your question is, yes, it would drop by 9 microns.

The answer is 9 microns, roughly.

That was this week's episode of Science with Dr. Carl.

Thank you so much for tuning in.

Lucy Smith will be back with you next week.

But in the meantime, if you want to leave us a five-star review,

that would be greatly appreciated.

This episode was produced by the wonderful Sarah Harvey,

and I am Bec Charlwood.

Catch you later.

See you later.

Dave Marchese here,

from the Triple J Hack Team.

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