Digging Through the Planet: The Geography of Antipodes

Rob Bell:
Hello, and welcome to Sketchplanations The Podcast, sharing facts, ideas, and philosophies to help fuel your own interesting conversations.

I'm engineer and broadcaster Rob Bell.

That there is the creator of Sketchplanations, Jono Hey.

Hello, Jono.

Hello.

And this is entrepreneur and past winner of The Apprentice, Tom Pellereau.

Hello, Tom.

Hello.

This time we're talking about Jono's sketch that explains antipodes, or is it antipodes?

I'm not sure.

You'll see Jono's sketch for this as the artwork for the episode, but if you head to sketchplanations.com, you can find it in its full form.

Now, Jono, when I hear the word, especially when it's pronounced antipodes, I think of Australia and New Zealand.

But please tell us, is there more to this word than just that?

Jono Hey:
Well, I was told about this by a colleague at one point.

Rob Bell:
About what?

Jono Hey:
About the antipode to where you are at the moment.

Rob Bell:
The antipode to where you are at the moment.

Explain.

Jono Hey:
So the antipode is the point exactly on the other side of the planet if you were to take a line from where you're standing and draw it straight through the centre of the planet and come out the other side.

Rob Bell:
Gotcha.

Jono Hey:
So diametrically opposite, you take the longest line that you can draw from your feet to come out the other end of the planet and that is your antipode.

Rob Bell:
The confusion between our pronunciation here or about the pronunciation.

Antipodes is spelt the same way, right?

Antipodes.

And for us in the UK, we talk quite casually about the antipodes being Australia and New Zealand, right?

On the other side of the world as a kind of loose sense, whereas this is a very specific sense and very relative to wherever you are, your exact point on the earth.

Jono Hey:
That's right.

And you know what?

I am familiar with that use of antipodes.

Rob Bell:
Yeah.

Antipodean as an adjective.

Jono Hey:
Yeah.

But I was really talking about this geographical physical sense of the antipode.

So you can be standing anywhere on the planet and you have an antipode, which is your point directly opposite.

So it's not just things in that part of the world.

It is wherever is opposite from you.

And I picked out an example in the sketch of New Zealand and Spain.

So if you stand in Spain, there are certain points in Spain where the longest line through the center of the planet has you coming out in New Zealand.

And there were a few other ones like that.

So for example, if you're in Hawaii, you're opposite Botswana.

If you're in Argentina, you are opposite some parts of China.

Chile overlaps a bit with Russia.

And I think you can do a more like an East-West antipode, which is essentially around the equator.

So if you're in Ecuador, your point directly opposite is somewhere around Indonesia.

But I think what's quite interesting is actually, if you start to look at any of this, and Tom, I was looking at you figuring this out just before that.

Rob Bell:
Yeah.

Jono Hey:
Almost everywhere you do this, except for some of these few places which I've mentioned, you end up in the ocean.

So your antipode is somewhere in an ocean.

And I think what is remarkable, and actually I only realized somewhat later in life, honestly, that most of the land is in the Northern Hemisphere, and far more of the people, which is really why most of the antipodes don't end up on a bit of land on the other side of the planet, that you're in the middle of the ocean.

I was looking at some of the stats, and for example, I think Northern Hemisphere has like 68% of the land, Southern Hemisphere about 32%, and Northern Hemisphere has around 87% to 90% of the population of the planet, and only 10% to 13% in the Southern Hemisphere.

Rob Bell:
And when you add to that the fact that I think around 70% of the earth is covered by our seas and our oceans, then it's no surprise that most antipodes are in the water somewhere.

Yeah.

Jono Hey:
Yeah.

And you know, it's one of these ones, I feel like you spend all the time growing up like looking at maps, and typically you end up with the Mercator Map.

And I've always sort of focused the Mercator sort of skews more of the Northern Hemisphere and makes it larger than the Southern Hemisphere.

Rob Bell:
Yep.

The Mercator Map being the map of the entire world, the sphere, if you like, of the globe being flattened out and how that is presented to us.

Jono Hey:
Yeah.

And a separate sketch on that, which we can talk about sometime.

And it was really interesting.

Like it allows you to do essentially straight line navigation, but it distorts everything.

And so that's actually, I think, if you grew up in the Northern Hemisphere, one of the ones you're most familiar with.

And so you actually have quite a distorted view.

And actually, particularly if we grew up in Europe, and so you tend to put naturally your country's center of the map.

And if you do that, what you end up doing is you break up the Pacific Ocean on the left and the right of your map.

Rob Bell:
Yes.

Jono Hey:
And you also, the Mercator Projection, shrink everything in the Southern Hemisphere somewhat.

Rob Bell:
Yeah.

Jono Hey:
And so you neglect to the fact that you can pretty much, and I've got this here, this is my prop for this.

You can't see it, but I've got a globe in my hand.

Rob Bell:
Lovely.

Jono Hey:
Because obviously, if you look at a flat map, everything the furthest on the right is actually the point furthest on the left, because it obviously goes around.

And I can look at this thing here, and almost the entire view of this globe I'm looking at is the Pacific Ocean.

It's almost completely blue from that vantage point.

And actually, if you turn it up, and this is very rare, do you ever do this?

If you look at it from Antarctica, straight from the bottom of the planet, so to speak, it's almost all blue as well.

That's because the Southern Hemisphere is vastly more water than it is land compared to the Northern Hemisphere.

Which is why, when you do an antipode, most of them end up in the ocean, which I never really, really think about that much before.

Tom Pellereau:
Yeah.

Jono, thank you, because I had never heard of antipodes.

Like Rob, I had heard of antipodes.

This is exactly the kind of thing that my son Jack would ask.

Daddy, if I was to drill through the center of the earth from here, where would I be?

It would be on that list of questions that kids ask.

Daddy, who do you think has kicked the ball more times, Ronaldo or Messi?

Or you're kind of on a beach and you go, Daddy, how many grains of sand are there on this beach?

Kids always have those sort of amazing questions, don't they?

Thankfully, now we have sort of ChatGPT, you can go, I don't know, Jack, but let's ask this.

Antipodes, great new word.

And next week, I'm going to be in China, which is the Antipode of Chile, which Jono, you and I went to about 20 years ago on that brilliant trip.

Jono Hey:
Yeah.

I have here a lovely book called Marvellous Maps.

And one of the maps it's got is called an Antipodal Map, which is basically you take the regular projection of the Earth that you know, and then you take the other one, you turn it upside down and back to front and put it overlaid on top of the other one.

Rob Bell:
And that's a mind bender.

Jono Hey:
Yeah, no, it is.

But it actually shows you really clearly that most of the continents sit over ocean on the opposite side of the world.

Rob Bell:
That's interesting.

Jono Hey:
So like most of Europe, Africa and Asia, because the Pacific is so damn big, sit over the Pacific.

Australia is sort of over the North Atlantic, most of North America sort of over the Indian Ocean.

And you can see that really clearly, which actually would have been a lovely addition to the sketch.

Rob Bell:
An interesting fact I found is that the Australian mainland is the largest landmass with its antipodes entirely in the ocean.

So none of Australia overlaps on that map you've just described as well.

Jono Hey:
Yeah, just give me just give me a second because I've got the map on the floor.

Rob Bell:
Oh, he's got more.

Have you got that?

You've got the overlay map there.

Tom Pellereau:
Jono loves the map.

Jono Hey:
Sorry, he doesn't.

Rob Bell:
So you've got that overlay map there with you.

Jono Hey:
It was just out of reach.

Yeah, you guys.

Oh, yeah.

Rob Bell:
Nice.

Jono Hey:
I don't know how precisely done this one is.

But yeah, you see like North America almost directly mirrors the Indian Ocean and yeah, Australia fits sort of neatly in the North Atlantic, remarkably.

Rob Bell:
That's brilliant.

Jono Hey:
Which is quite, quite neat.

Rob Bell:
I feel like, like culturally in the UK, we talk about the other side of the world, antipodes.

But we again, we casually kind of refer to the other side of the world as being Australia, right?

In the UK, where it's not, we're in the sea.

But I was trying to find out what that cultural reference is for the US.

And I might be wrong in this, but I think it could be China, not geographically, I should say.

Jono Hey:
Yeah.

Rob Bell:
But culturally, they refer to the other side of the world as being China.

Now, I might be wrong in that, but if I'm not, and if I may be so bold, that feels a bit silly because the USA is in the Northern Hemisphere and China is also in the Northern Hemisphere.

How can it be on the other side of the world?

Tom Pellereau:
Depends on where you're digging.

Rob Bell:
Well, through the core.

Tom Pellereau:
You don't want to dig through that core.

It's very hard, the core.

Rob Bell:
Well, that's what we're talking about.

Tom Pellereau:
You know, any sensible person would go through the site and get it right.

I'll tell you what, let's start digging and we'll see.

Jono Hey:
If you were to do a sort of flatline parallel with the slice at the equator, yeah, then I think you do sort of naturally end up in middle of Asia somewhere from North America.

Rob Bell:
Yeah, but in the Southern Hemisphere, right?

Jono Hey:
If you do it perpendicular to the surface, yes, you have to dig parallel to the equator and then you'll come out.

You'll come out China.

Actually, you know, there was a nice thing, and I didn't realise this until more recently, but like the pod from antipode, which is why I say that, it's the same pod as podiatry.

It means basically feet.

So it kind of means opposite feet.

So it's the people on the planet who have their feet opposite to you.

Rob Bell:
If you squish the earth flat, and they were standing there, and you're standing on their feet.

Yeah.

Yeah.

The soles of your feet and the soles of their feet would come together.

Oh, lovely.

Tom Pellereau:
Links very nicely to another question, I'm sure Jack's probably asked them before, which is, who has dug the deepest into the core?

I wonder what the record is for the deepest dug down.

Jono Hey:
Well, it looks like Jono might have the answer to me.

No, because it's a good question, isn't it?

Because first of all, how far is an antipode?

How far away are they from you?

Rob Bell:
Yeah.

Jono Hey:
So I believe they're around 7,900 miles.

So that is essentially the diameter of the earth.

Tom Pellereau:
So that in itself is like a 14-hour flight.

Jono Hey:
Yeah.

Tom Pellereau:
As you were, if there was a tunnel.

It's a long way.

Rob Bell:
I've got it.

To fly there is a 20,000-kilometer flight.

We're mixing apples and pears here, kilometers and miles.

Tom Pellereau:
So to go around the earth is 20,000.

To go straight through is 7,900.

Jono Hey:
I'm digging through 7,900 miles.

Tom Pellereau:
So even if you could fly, drop faster.

Jono Hey:
You drop half of it and then you have to climb out the other side.

It's always fun to think about.

But the biggest hole, at least from the book I've got, was we've only ever dug 7.6 miles.

Rob Bell:
That's a long way down.

Jono Hey:
Which is an incredible, incredible way down.

But when you compare it to 7,900.

Tom Pellereau:
But it's not even a percentage, right?

It's a 0.1, not even 0.1%.

Rob Bell:
Yeah.

Gosh.

Jono Hey:
Exactly.

So it's a really long way.

Tom Pellereau:
The planet is big.

Jono Hey:
I had another sketch a long time ago, which was just so simple about this fact that the crust of the earth, which is the bit that we think is pretty decent and big, is about the same as the skin of an apple.

Rob Bell:
Nice.

In terms of its thickness.

Jono Hey:
In terms of its thickness.

Yeah.

It's proportional.

So it's this tiny little fraction that we've ever got anywhere near.

So when Jack asks you, Tom, you can say, we've dug 7.6 miles, but as you say, was it 0.1% of the way down to your antipode?

Tom Pellereau:
Nice.

Rob Bell:
Some interesting bits about, because the three of us are based in Britain, there are no parts of Great Britain that have antipodes on land.

There are United Kingdom land-based antipodes because we can consider the British overseas territories like the Pitcairn Islands, Gibraltar, South Georgia Island.

So the Pitcairn Islands, you come up near Doha in Qatar, Gibraltar near a beach near Auckland in New Zealand, and South Georgia Island, you pop up somewhere in Russia.

Jono Hey:
I mean, if you're a tiny little island in the middle of the ocean, there's a strong chance that you do have a land-based antipode as we've established.

Rob Bell:
Yes.

Good point.

Jono Hey:
Yeah.

Particularly in the Southern Hemisphere.

Rob Bell:
Lovely.

Jono Hey:
Just two interesting facts, I think.

One is that one of the little terms that I quite like is something called the Great Circle, which is imagine if you had a hoop, like a hula hoop, and you centered it around the middle of the earth and spun it.

All of those are what's called a Great Circle route.

You're going in the longest possible way to come back to where you were.

So that's quite striking.

If you're in Europe and you look at a world map, if you imagine going to the west coast of the US., it looks like you ought to fly across the US to get there.

But in fact, you don't.

You take the Great Circle route, which is basically takes you over the top of, over by the Arctic.

Rob Bell:
Greenland, Canada.

Jono Hey:
Yeah, in order to get there.

So I think the Great Circle is quite a nice little term.

And then the other one about this is that not all antipodes are quite equal because the Earth is not a perfect sphere.

Tom Pellereau:
Yes.

Rob Bell:
Good point.

Jono Hey:
And I think the term for it was an oblate spheroid.

Rob Bell:
Yes.

Tom Pellereau:
Okay.

Jono Hey:
Which is if you imagine like you put your fingers at the North Pole and the South Pole and you spun it, which is what's essentially happening.

Rob Bell:
Yeah.

Jono Hey:
The mass around the middle is going faster around the equator and is getting pulled out slightly more than the rest of the planet.

So it's slightly sort of bulgy in the middle.

Rob Bell:
Squished slightly.

Jono Hey:
Yeah.

So the areas around the equator are actually further from the centre of the Earth than other parts of the planet further north and south because it's not perfect sphere.

Rob Bell:
So if you were to find antipodes on the equator and measure the distance between them and then you measured the distance between the North and South Pole antipodes, the North and South Pole is going to be shorter than the distance between the antipodes on the equator.

Jono Hey:
I would say, though I've not done it.

Yeah.

That makes sense.

So, Ecuador to Indonesia is further than North Pole to South Pole, I would presume.

Rob Bell:
Yeah.

Good.

I've just found something here about my tunnel through the earth.

Tom Pellereau:
You get zero gravity in the middle, right?

Rob Bell:
Well, the most interesting thing that I saw in here is that it would take about 42 minutes to go from one side of the earth to the other if you just jump down it.

But then you'd oscillate.

Yeah.

No, you'd go faster and faster and faster and faster until you hit the middle.

And then you start slowing down, slowing down, slowing down until you got to the other side.

And then you'd oscillate straight back down to where you came from.

And you'd just go back and forth.

Jono Hey:
It's the most epic bungee jump you can imagine.

Rob Bell:
That's frictionless.

If it were a frictionless tunnel, I might add.

Tom Pellereau:
And you didn't hit the sides.

Jono Hey:
You didn't hit the sides.

We find a small dwarf planet to mess around with.

Tom Pellereau:
That's one deep well.

Jono Hey:
Very cool.

Rob Bell:
If anybody was interested, I did find quite a fun website.

Tom Pellereau:
Digging a hole with you?

Rob Bell:
No, that's a separate website.

I'll be asking for subscribers to that scene.

I found a website called antipodesmap.com, where you can type in any location.

It'll tell you what your antipode is, which is quite fun.

Tom Pellereau:
Nice.

Rob Bell:
Thank you very much, chaps.

Another fun and informative chat.

Thank you all for listening.

And wouldn't it be great, right now, if there were two of our listeners out there in the world who are antipode-related?

Jono Hey:
What are the chances?

Rob Bell:
Wherever you are, go well, stay well.

Cheers.

All music on this podcast series is provided by the very talented Franc Cinelli.

And you can find many more tracks at franccinelli.com.