0:00

I'm Dr Karl coming to you from

0:02

the lands of the Gadigal people of

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the Eora nation. I acknowledge Aboriginal and

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Torres Strait Islander peoples as the first

0:09

Australians and traditional custodians of the lands

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where we live, learn and work. G'day

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Dr Karl Schulteres of Science University of Sydney.

0:17

Today I'm talking with Dr

0:19

Kate Howells. Is that the correct pronunciation?

0:21

Howells is correct but I'm not a

0:24

doctor. You've written this amazing book called

0:26

Moons and there are so

0:28

many things I learned I thought it's going

0:30

to be a really interesting sort of summary

0:33

and I had no idea that there

0:35

is a moon in our solar system

0:37

that has twice as much water on

0:40

it than all of planet Earth. That

0:42

there is an active volcano that pops

0:44

somewhere on one of the moons every 500 days or so. I

0:48

knew that Jupiter had more mass than

0:50

all of the other moons

0:52

and planets and etc put together but

0:54

I didn't know it had twice the

0:56

mass and you're saying that it generates

0:59

internally twice as much heat as the

1:01

sun gives it. How's that happen? Jupiter

1:04

is big enough that

1:06

it is almost creating

1:08

fusion in its core. I think it would

1:10

need to be 17 times bigger which

1:12

is you know quite a lot bigger. It would

1:15

start fusing atoms in its core and

1:17

become a star. So it's got a

1:19

little bit of that process happening already.

1:22

Gravity is so strong in its center

1:24

that it does create that kind of

1:26

heat. It's also very

1:28

far away from the sun and so

1:31

those two things combined yeah does create

1:33

this very unusual phenomenon that Jupiter is

1:35

out there creating more warmth than it

1:37

receives. It's also got

1:39

this incredible radiation field and

1:43

apparently I didn't know this either but the

1:45

Pioneer spacecraft 10 and 11 when they

1:47

went past they took photos and

1:50

the radiation was so intense it wiped it.

1:52

The radiation field if you got close to

1:54

Jupiter would be enough to kill a human.

1:57

You also point out that you have

1:59

the large largest active volcano

2:02

on one of the moons up

2:04

there. Io is one of Jupiter's

2:06

large moons. It has four large moons. Io

2:09

is the innermost of those big ones. And

2:12

it is the most volcanically active body

2:14

in the solar system. It has hundreds

2:16

of volcanoes across its surface, including this

2:19

one, Loki, which is its biggest, and

2:21

it is the largest active volcano in

2:23

the solar system. And

2:25

the reason that Io is this way

2:27

is because as it orbits very close

2:29

to Jupiter, it has these other large

2:32

moons orbiting a little bit further out. And

2:34

so there's this sort of gravitational tug of

2:36

war happening. So as a big moon passes on

2:39

the other side of it, it gets pulled a

2:41

little bit that way. As it goes around, Jupiter

2:43

gets pulled a little bit towards Jupiter. That

2:46

gravitational tug of war creates friction

2:48

inside it that warms up its

2:50

interior and creates all this volcanic

2:52

activity. So there's almost constant

2:54

eruptions happening on its surface. And again,

2:56

because it's a small body, it's smaller

2:59

than Earth's moon, it doesn't

3:01

have the gravitational pull keeping things small.

3:04

So on Earth, volcanoes can't get that

3:06

tall. Mountains can't get that tall because

3:08

they're all getting pulled down towards

3:11

the Earth's center by gravity. On

3:13

Io, there's not that same gravitational

3:15

pull to keep things tight. So

3:17

volcanoes can reach these ridiculous heights

3:19

like you see with Loki. The

3:23

eruptions can go up hundreds of

3:25

kilometers. Yeah, so some of the

3:27

volcanoes on Io shoot lava and

3:30

gases even further. Those

3:32

can reach out all the way

3:34

out into space and actually get swept back

3:36

up into Jupiter's mass. So

3:39

Jupiter is gaining some of the material

3:41

from Io as Io spews all of

3:43

its innards out into space. I

3:46

was lucky enough to be alive when

3:49

Voyager went past. And we

3:51

were thinking, oh yeah, we'll get some nice photos. And

3:53

then everybody's going, hey, do you hear? There's

3:56

a volcano on Io. And

3:59

it happened to erupt. at the exact moment we

4:01

took a photograph of it. And it was on

4:03

the horizon on the rim of the disk, so

4:05

it stood out rather than being in the middle

4:07

of the body. What an amazing thing that was.

4:11

I can see why you'd get fascinated by it. Yeah,

4:13

I actually saw a documentary called

4:15

The Farthest about the Voyager spacecraft,

4:18

the twin missions. And it

4:20

talks about the person who made that discovery.

4:22

And it was a young woman, I believe

4:24

a grad student who was analyzing the data

4:26

and the images as they came back. And

4:29

she was the one who spotted that. And

4:31

she talks in the documentary about what

4:33

it felt like to be the first

4:35

person in all

4:38

of humanity to ever see a volcanic

4:40

eruption on another world. That's part

4:42

of what I love about space is that

4:44

the human experience of discovering

4:46

these things is so powerful. And just

4:49

to imagine what that would feel like

4:51

is so moving. You know, the big

4:54

moons of Jupiter, Galileo had to get

4:56

his telescope made and he saw it.

4:58

It turns out that just as a

5:00

completely irrelevant side thing, an

5:02

eagle has sharp enough vision

5:05

to be able to see the moons of Jupiter. What?

5:08

That's amazing. Well, it's got to find

5:10

little dots in the sky from a

5:13

long distance and then find them and

5:15

then go and kill them. And so

5:17

it makes sense that a top predator

5:19

like an eagle would have super sharp

5:21

vision. And then you go

5:23

into some of the other moons, Europa. How

5:25

do you get a name like Europa, like

5:28

Europe, when you chop off the universe, and

5:30

apparently you're saying it's got twice

5:33

as much water than all of

5:35

planet Earth, but it's

5:37

only smaller. What's going on? I can actually

5:40

tell you why it was named Europa

5:42

as well. It's an interesting story. Jupiter's

5:44

moons are all named after the

5:47

god Jupiter's consorts. So

5:49

Jupiter had all kinds

5:51

of lady friends. Yes,

5:56

his wife Juno, who the

5:59

Juno space craft is named

6:01

after was famous for jealously

6:03

hunting down his consorts and

6:06

doing horrible things to them and Europa is

6:08

one of them. And I'm guessing that that's

6:10

what Europe is named after as well. Lots

6:14

of Greek and Roman mythology in the

6:16

world of space. But

6:19

yeah, so Europa is this moon

6:21

of Jupiter. It is

6:23

the second largest moon out

6:26

from Jupiter. And it has

6:28

the same kind of process happening

6:30

on it that Io has where

6:32

it's getting squeezed by Jupiter's gravity

6:34

and by the gravity of these other

6:36

large moons. But whereas

6:38

Io is a rocky moon and so when

6:41

it gets squeezed and its interior heats up,

6:43

it creates magma. Europa

6:47

is an ice moon because out at Jupiter temperatures

6:49

are very low and so water is

6:53

ice as hard as granite. But

6:56

the ice inside Europa is

6:58

squeezed and heated up and

7:00

that turns into water. So

7:03

underneath a crust about 30 kilometers

7:06

thick, there is this huge

7:08

global ocean of water.

7:12

It winds up being they think about twice as

7:15

much water as we have in all the oceans

7:17

and lakes and rivers and everything on Earth. And

7:20

that's because Earth just has this

7:22

pretty shallow covering of water and

7:24

only on some parts even though the oceans

7:26

are so enormous. It's not very,

7:28

very deep. The oceans on

7:31

Europa are I think as deep as

7:33

100 kilometers. In

7:35

fact, you'll find book it's called moons by

7:37

Kate Howells. It says up to 300 kilometers.

7:41

There you go. I knew it was very deep. Thank

7:43

you. Because the moon is basically

7:45

just ice and water, it can hold an enormous

7:48

amount. And so people are

7:50

very excited at this prospect because when

7:52

we look for the possibility of life

7:54

existing somewhere else beyond Earth, we tend

7:56

to look for where there's liquid water

7:59

because all life on Earth relies

8:01

on liquid water. It's the one

8:03

thing that all life forms have

8:05

in common is they need some

8:07

kind of water. So the possibility

8:09

is out there that maybe underneath

8:11

the crust of Europa there might

8:13

be some little bacterial life forms

8:15

swimming around. Now

8:18

Kate, on page 19, you

8:20

once again told me something I had never

8:22

ever thought of, that

8:24

Io, a moon around

8:26

Jupiter, and Earth's moon are

8:29

the only large rocky moons

8:31

in the entire solar system.

8:33

Everything else is either small

8:35

and rocky or large

8:38

and icy, but only two

8:40

of them are large and rocky. And

8:42

I had no idea. You kind

8:44

of mentioned this, that because the temperatures

8:46

are so low, you can have

8:49

something like water or methane being an

8:51

ice, and then that acts

8:53

effectively as a solid substance, but it's

8:55

not rock, which is based on silica.

8:57

It's based on other chemicals. Thank you

8:59

for blowing my mind on that one.

9:01

I had no idea of that concept.

9:03

And actually the former planet Pluto, the

9:05

dwarf planet Pluto is another icy world

9:07

where it's mountains and everything are made

9:09

of ice. Because again, it does behave

9:11

like rock at those very, very low

9:13

temperatures far away from the sun. You

9:15

can have the exact same kind of

9:17

processes. Like I said earlier, it's as

9:19

hard as granite. So what you imagine being

9:21

able to do with granite or what nature

9:23

can do with granite, it can do with

9:25

ice when it's that cold. It

9:27

was a shame when they got rid of Pluto. One

9:30

of the people I work with in my school of physics

9:32

at the University of Sydney, I kind

9:34

of had a go at him for getting

9:36

rid of Pluto and he said it was an honest mistake

9:38

at the time. See,

9:40

I'm kind of on the other side of this

9:43

where I think it's just fine that

9:45

we demoted Pluto because it's important to

9:47

learn about things other than planets. And

9:49

just because Pluto is not a planet

9:51

anymore doesn't mean it's less interesting or

9:53

less important or less worth learning

9:56

about. And now people know about

9:58

the concept of dwarf planets. so

10:00

they can learn about Eris and

10:02

the really interesting dwarf planets out there.

10:05

Well, it is good to get it right,

10:07

Koo. You recently had an eclipse going across

10:10

North America and a

10:12

politician in Texas said,

10:15

and I quote, the moon

10:17

is a complete rounded circle, comma,

10:20

which is made up mostly of gases, 100% wrong.

10:25

And that's why, comma, the question is why

10:27

or how could we as humans live on

10:29

the moon? Are the gases such that we

10:31

could do that? That politician

10:33

was totally wrong. But one

10:35

other thing that I had

10:37

no idea of, on

10:40

page 58, you talk about the

10:42

moon had volcanic

10:45

activity as recently as 50 million

10:48

years ago. And I'm thinking, what?

10:51

I thought it would have died out like a

10:53

long time ago. And then you're

10:55

saying that the atmosphere was

10:57

twice as thick as Mars.

10:59

Well, Mars's atmosphere is if you go to

11:02

1% of the thickness of the Earth, and

11:04

then you go to 0.6, that's

11:06

Mars, and it had volcanic

11:08

activity. Can you

11:11

tell me more about that? And how come

11:13

there are few, this is something I didn't know

11:15

either. Thank you for getting to see me straight.

11:17

Why there are fewer craters on the

11:19

side of the moon that faces us than the other

11:21

side. I know the audience is mind like here,

11:23

blue mind. So

11:26

Earth's moon, I

11:28

always thought it was boring compared to the

11:30

other moons of the solar system because it

11:32

doesn't have volcanoes all over it right now,

11:34

and it doesn't have oceans of liquid water

11:37

under the surface or anything like that. But

11:39

it's actually got a really cool history. We

11:42

think the best leading theory is that the

11:44

moon formed about four and a half billion

11:46

years ago in the early days of

11:48

the solar system, when the early Earth was

11:51

smashed into by another early

11:53

planet, something about the size of

11:55

Mars, that collision

11:57

annihilated that other planet and kicked

11:59

it off. up just a ton

12:01

of debris that coalesced into the

12:03

moon. That process

12:06

of it coming together gravitationally

12:08

to form the moon happened relatively

12:10

quickly and created a

12:12

ton of heat just from all

12:14

of that energy. And so the

12:16

moon for a long time for I

12:19

think hundreds of millions of years was

12:22

molten, like it was just

12:24

a magma sphere. It

12:26

gradually cooled down from the outside in.

12:28

So the crust formed

12:31

and then gradually the interior cooled

12:33

and that took a long time.

12:35

So up until about 50 million

12:37

years ago, there was still volcanic

12:39

activity. So, you know, I

12:41

think the eruptions that would have been happening through

12:44

a thinner crust with magma underneath the surface like

12:46

we have on Earth, that would

12:48

have gradually slowed down up until about 50

12:50

million years ago. What I like to think

12:52

about is 65 million

12:54

years ago was when the dinosaurs ruled

12:56

the Earth. I know this from Jurassic

12:59

Park. And so I'm

13:01

not a paleontologist. I like to think

13:03

about the dinosaurs roaming the Earth. And

13:06

meanwhile, there are volcanoes going off on

13:08

the moon above them. So

13:10

it was a much more dynamic world

13:13

than it is now up until very recently.

13:15

I mean, 50 million years ago does sound

13:17

like a long time, but it's a blip

13:19

in the cosmic scale. And the

13:21

reason that it is different on one

13:23

side than the other. If you ever see pictures of

13:25

the far side of the moon, it looks very different

13:27

from the near side of the moon. The near side,

13:29

I mean, first of all, people might

13:31

not know that the moon always shows us the same

13:33

face. So that's why when you look up at the

13:35

sky, you always see

13:38

those very familiar sort

13:40

of shapes, the sort of dark splotches on

13:42

the moon. As it orbits the Earth, it

13:44

rotates at just the right speed. So it's

13:46

always pointing towards the Earth with the same

13:48

face. The reason that happens

13:50

is actually really common in the universe

13:53

for things to be tidally

13:55

locked, we call it. And that's because

13:57

as something is orbiting, the gravity of

13:59

the object that it's orbiting. So in

14:01

this case, the Earth's gravity pulls on

14:03

the moon and kind of pulls some material closer.

14:06

So one side of the moon gets

14:08

like a little bit denser. And then that part of

14:11

the moon gets sort of attached

14:13

gravitationally to the Earth a little bit

14:15

more. So it wants to point in

14:17

that direction. And then that has a

14:19

sort of feedback loop where then that

14:21

part gets a little bit thicker again.

14:24

And so then it keeps pointing to

14:26

it and it just reinforces itself. The

14:28

point is when this tidal locking process

14:30

was taking place and when the moon

14:32

was cooling down from having been completely

14:34

molten, the Earth was also super hot

14:36

because when it got smashed into by

14:38

that protoplanet in the collision

14:41

that created the moon, that kicked

14:43

up a lot of stuff on the Earth as well.

14:45

It created a lot of energy. And so it was

14:48

a pretty magma heavy surface

14:50

on the Earth at that time.

14:52

So that was actually heating the

14:54

moon. So the side of the moon that was pointing

14:57

towards the Earth is kind of still

14:59

getting cooked by this hot Earth. Meanwhile,

15:01

the back of the moon that's pointing

15:03

out into space all the time is

15:05

just staying very cold because it's just pointing

15:08

towards the coldness of space, sometimes towards the

15:10

sun, but it's not getting that magma heat.

15:13

So it cooled more quickly and

15:15

formed a thicker crust. So

15:17

when you look at the moon and you

15:19

see those dark splotches, those are

15:22

actually the remnants of volcanic activity.

15:24

So darker material from inside the

15:26

moon would erupt out of these

15:29

volcanoes and settle into impact craters

15:31

to form what are called volcanic

15:33

basins. So the dark parts of

15:35

the moon are volcanic

15:38

material that settle into these basins. You

15:40

don't see that on the far side.

15:42

The far side looks pretty uniform with

15:44

impact craters and such, but without these

15:46

kind of big features. Well,

15:48

so let me get this straight because I've

15:51

been wanting to know this for a long

15:53

time and yours was the first explanation that

15:55

really hit it for me. So

15:57

back in the early days, there were lots of rocks.

16:00

floating around there were lots of rocks running

16:02

into the earth and the moon. And back

16:05

then the earth was still very

16:07

very hot and so with

16:09

the moon you'd have one

16:11

side of the moon facing deep

16:13

space at a temperature of minus

16:15

270 degrees C. Okay you got

16:17

the Sun there but that's only half a degree

16:20

of the sky and the risk was really cold

16:22

so there's a big what you call temperature gradient

16:24

but the other side of the moon is facing

16:26

the earth which is a like a thousand degrees

16:28

Cetera gradient so it takes longer to cool

16:30

the volcanoes run for longer and

16:33

they then obliterate the crater

16:35

impacts. Have I got it right? Yeah

16:38

so the really big impact craters where you have

16:40

the dark material that settled into them those

16:43

are remnants of a much earlier time but

16:45

the sort of peppered craters that you

16:47

see on the far side of the

16:50

moon those just never got reworked by

16:52

volcanic activity like the reason for example

16:54

that the earth doesn't have a whole

16:56

bunch of craters on it even though

16:59

it was bombarded heavily earlier in the

17:01

solar systems history is that our tectonic

17:03

and volcanic activity reshapes the

17:05

surface it sort of refreshes the surface

17:07

all the time it blends out all

17:10

of those craters so you had that

17:12

kind of blending happening on the

17:14

more volcanically active side of the

17:16

moon that had like the thinner crust and

17:18

because it was being warmed by the earth

17:21

so you'd have volcanoes smoothing things out and

17:23

on the far side it has more craters

17:25

because it's maintained that history because there was

17:28

just there weren't volcanoes. Wow that is

17:30

the first time I really have

17:32

an explanation of why the difference between

17:34

the two sides of the moon that I'm very happy with

17:36

thank you for that but the other thing that I had

17:38

no idea of you say

17:40

that there are lava tubes on

17:43

the moon now I've been in a lava tube

17:46

in the top right hand corner of Australia in

17:48

a place called Cairns and it

17:50

was maybe 30

17:54

meters in diameter it was

17:56

huge and you're saying that there

17:58

I don't come across it before You're saying there

18:00

are lava tubes on the moon. How do we

18:03

find out about that? You can

18:05

actually see evidence of lava tubes on

18:07

the moon from what they call

18:09

skylights where the lava tube has

18:11

collapsed. And so you can see

18:14

this pothole kind of from

18:16

the surface. Basically while

18:18

the moon was still volcanically active, there

18:20

would be lava flowing on

18:22

the surface. The coldest of space would

18:25

cool the very top layer of that

18:27

lava and form hard rock,

18:29

but underneath that hard rock, the lava would

18:31

continue to flow until it had kind of

18:33

all flowed out and it would leave this

18:36

empty tube. And we do have this, like

18:38

you say on earth, we have lava tubes

18:40

as well, but they're much bigger on

18:42

the moon for the same reason that

18:45

Io has humongous volcanoes is just

18:47

that gravity is much weaker. So

18:49

you can have these massive caverns,

18:52

these massive tubes sustained without the

18:54

roof caving in because there's not

18:56

that much gravity pulling the roof

18:58

down, the lava tubes on the moon are

19:00

big enough that you could build a whole

19:02

city with skyscrapers and everything inside it. And

19:04

actually, um, there's, there

19:07

are plans in place to further explore and

19:09

study lava tubes on the moon, uh, as

19:12

part of these, this sort of ongoing effort

19:14

to have human presence expand

19:17

on the moon. So we've got the

19:19

U S and its international partners heading

19:21

to the moon and then in the

19:23

coming decade, and they really

19:25

want to try to expand the

19:28

human presence on the moon in a more sustainable

19:30

way. Perhaps someday we'll build

19:32

a lunar city inside a lava tube. I

19:34

think that would be really cool. There

19:37

are a whole bunch of moons in

19:40

our solar system that you like and

19:42

that also have water on them. The

19:44

one that really blew my mind was

19:46

Enceladus, a moon of

19:48

the ringed planet Saturn, in

19:50

my mind, one of the prime contenders for

19:53

life in our solar system. Yeah,

19:55

absolutely. So Enceladus is

19:58

very similar to Europa in that. it

20:00

is a icy moon that

20:03

for similar reasons has a liquid

20:06

water ocean underneath the

20:08

crust. What

20:10

makes Enceladus different

20:13

in terms of our access

20:15

to that ocean is that it

20:17

has these huge geysers that spew

20:19

that water out into space. If

20:22

we were to try to get a sample of the

20:24

water in the oceans of Europa, we'd have to

20:26

drill through 30 kilometers of

20:28

ice that's as hard as granite.

20:32

You can imagine, not easy to

20:34

do. 30 kilometers, that's pretty deep

20:36

to drill. But

20:39

on Enceladus near its south pole,

20:41

there are these fissures that send

20:45

huge eruptions of water from

20:47

that ocean out into space.

20:50

The Cassini spacecraft that was

20:52

orbiting Saturn in

20:54

the 2000s, it actually flew through

20:56

one of those plumes and sampled

20:58

it. It didn't have on board

21:01

the instruments to look for signs of

21:03

life in that water, but

21:05

it did sample that water and send

21:08

back a bunch of data that is

21:10

still being analyzed to this day. People

21:12

are still making discoveries about what might

21:15

be in the waters of Enceladus. Part

21:18

of what makes Enceladus really intriguing is

21:20

that it seems to have hydrothermal

21:22

vents in that

21:24

subsurface ocean. This

21:27

means that the ocean waters are in

21:29

contact with a rocky seabed

21:31

like the waters on Earth. That

21:34

rocky seabed has hydrothermal vents

21:37

so that they shoot super

21:39

hot water and gases out

21:41

into the ocean. It's hydrothermal

21:43

vents on Earth are where we think probably

21:45

life originated on this planet. It's one of

21:48

the contenders. It's not for sure, but that's

21:50

what we think is quite likely. It

21:53

combines water, which as we know

21:55

life needs, with an energy source. This energy coming from the core

21:57

of the Earth is going to be a huge part of the

21:59

planet. getting shot into the water, those

22:02

are ingredients for life. So

22:04

we have evidence that Enceladus may

22:06

also have hydrothermal vents, shooting energy

22:08

into these subsurface waters. The thick

22:10

layer of ice also protects that

22:12

water environment from the harmful radiation

22:15

that you would experience if you

22:17

were right out on the surface.

22:19

Earth is protected from radiation by our

22:21

magnetic field. Without a magnetic field, you're

22:23

not gonna last very long just living

22:26

on the surface, but underneath that ice,

22:28

it's possible. So these are just a

22:30

few of the reasons why Enceladus is very

22:32

intriguing in the search for life. There's

22:34

a wonderful Scientific American article,

22:37

and it goes through it in great details. It's

22:40

just entirely on Enceladus. And the thing that blows

22:42

my mind about the hydrothermal vents is

22:44

that they are at the peaks

22:47

of the longest mountain range

22:49

on Earth that almost none

22:51

of us will ever see. And

22:54

this mountain range is 40,000 kilometers long, and

22:57

it runs along the ocean floor, rising up two and

22:59

a half kilometers up from the ocean floor. So the

23:01

top is about two and a half kilometers from the

23:03

surface. And at the top, we've discovered some 500 of

23:06

these hydrothermal

23:08

vents with the water, as you said, squirts out

23:10

at up to 400 degrees C, and

23:14

it's kept liquid by the pressure above it. And in

23:16

it, we find all the chemicals of life and

23:18

the energy that the life

23:20

forms need to survive comes not from

23:22

the sun, but from the heat.

23:24

And they live off that energy. And

23:27

we've found 500 of these colonies of

23:29

life, just weird creatures living entirely off

23:31

these hydrothermal vents as the hot

23:34

water comes up through the rock. There

23:36

are tiny particles of rock, four

23:39

to 16 nanometers in

23:41

diameter, a nanometer is a billionth of a meter.

23:45

And blow me down, the water squirts out

23:47

of Enceladus at 200 kilograms a second. And

23:50

we've found the same range of rocks,

23:52

four to 16 nanometers coming out of

23:54

Enceladus. And just in the last week,

23:56

they reanalyzed the data, and they found

23:58

there were another two. peaks of data

24:01

smaller than a micron. Those two peaks

24:03

correspond exactly to the diameter of bacteria

24:05

that live in the hydrothermal vents on

24:07

Earth. And I'm thinking, life, life, life,

24:10

there has to be life there. But

24:13

as you say, at the moment we've got

24:15

no proof. Look, we've come to the end.

24:17

We haven't even got to the fact of

24:19

Miranda having the tallest cliff in the solar

24:21

system. Miranda is a moon of? Uranus. And

24:23

a 20 kilometre high cliff. And the wonders

24:25

of landing on Titan and the stuff we've

24:28

found there, and the oceans of liquid methane

24:30

and ethane, and how Triton, there's

24:32

just so much stuff there. Triton

24:34

is probably a planet. Your book

24:36

is by Kate Howells, H-O-W-E-L-L-S for

24:38

Sierra. You were lucky enough, your

24:40

parents were wealthy enough to have a plural name, I

24:43

guess. And so it's

24:45

called Moons, M-O-O-N-S, Mysteries and

24:47

Marvels of Our Solar System.

24:50

And if you get this book, you'll learn so much

24:52

stuff like I did. So how can people follow you

24:54

and your fine work, Kate? So

24:57

I am not much of a social media

24:59

user. I do have a Twitter account. If

25:01

you want to contact me, it

25:03

is at spacekateh. But

25:06

most of my work is through

25:08

the Planetary Society. I'll just do

25:11

a quick plug. We are an

25:13

international organization that does public education

25:15

on planetary science and space exploration

25:17

topics. And we advocate

25:20

for increased funding, mostly for NASA. It's

25:22

a US-based organization, but we have members

25:24

around the world and we

25:26

do crowdfunding for projects. I write

25:28

articles and a magazine for the

25:30

Planetary Society. So you can find

25:32

more of my work on all

25:34

different topics, moons and otherwise at

25:36

planetary.org. I also have another book

25:38

that came out a few years ago called Space

25:40

is Cool as F. I will not

25:43

say the final word, but it's there. And

25:45

that's again, just on broader space

25:48

topics. And like moons has a

25:50

lot of really cool space imagery.

25:52

I think the photos that we

25:55

have of things out in

25:57

space are among the most accessible.