0:03

When someone is hurt in a truck

0:05

accident, the one question everyone has is

0:07

why did this terrible collision happen? To

0:10

answer that question takes an experienced team

0:12

of lawyers and experts. Not

0:14

everyone has this type of experience. At

0:17

Colombo Law, we are truck injury

0:19

lawyers. It's what we do every

0:21

day. When someone is

0:23

hurt by a truck, Colombo Law is the

0:25

law firm people call to get answers. Hurt by a

0:27

truck? Hurt by a truck? Call Colombo Law. Call Colombo

0:30

Law. again, thanks for joining us. This

0:32

is Space Nuts. Coming up, we're talking

0:35

Lagrange points, supermassive black holes,

0:37

dark matter and a what

0:39

if question about meeting

0:42

aliens and what we would want to know from

0:44

them. All coming up

0:46

on this edition of Space

0:48

Nuts. Space

1:00

Nuts. Astronauts report it

1:02

feels good. Okay,

1:06

Fred, shall we tackle some questions? We

1:09

should, shouldn't we? That would be nice. Yeah, I

1:11

guess so. Okay, well, we've got

1:13

a couple of text

1:15

questions to start off with. This one

1:17

comes from Jim Skelly in Plano, Texas.

1:19

He says, I have a

1:21

question about Lagrange points or Lagrange points.

1:25

If we look at the five Lagrange

1:27

points around the Earth and the Sun,

1:30

I can fully comprehend L1, which is

1:32

between the Sun and the Earth. I

1:34

can also understand L4 and L5, which

1:37

are 60 degrees ahead of and behind

1:39

the Earth's orbit respectively. I

1:41

can readily see where the force of

1:44

gravity between the Sun and the Earth

1:46

would be in balance at these three

1:48

locations. I really struggle

1:50

to understand L3, which

1:53

is on the opposite side of the Sun

1:55

from the Earth and L2, which is beyond

1:57

the Earth and is a popular location. positioning

2:00

telescopes like well, you

2:02

know the blanket and

2:06

the new European one that's gone up there too. I

2:09

cannot understand how gravity between the Earth and

2:11

the Sun is balanced at L2 and L3

2:14

locations. Can you kindly enlighten me?

2:17

Thank you for the answer and the great podcast

2:20

that you produce each week. It's not great

2:22

every week, I can tell you. Anyway,

2:26

it's a bit sick today. They

2:29

know about it, you don't have to tell them

2:31

it's not great, everybody knows. Now

2:36

a good question and I must confess that this

2:38

is one that confuses me as well. So

2:42

that's very very nice. It's

2:45

a fairly simple answer actually and you'll kick

2:47

yourself. So you'll

2:50

kick yourself because

2:54

there is another force involved. So

2:59

you've got gravity and yes, the

3:01

L1 sitting between the two, one

3:04

and a half million kilometres towards

3:06

the Sun from our own planet which

3:08

is that one percent of the

3:11

distance to the Sun pretty

3:14

well. Exactly, okay. So

3:16

that's easy to understand but the others

3:18

are totally counterintuitive especially the ones that

3:20

are outside the orbit of the Earth L2. But

3:26

the other force

3:29

that comes into this is centrifugal force

3:31

because the Earth is moving around the

3:33

Sun at 30 kilometres per second, takes

3:35

365.25 days to go around and that

3:37

generates an

3:41

outward force just as

3:43

spinning a wheel puts

3:46

an outward force up and there's the balance

3:48

between that and the gravity that

3:52

it's a marvellous thing really. It's another

3:54

of these wonderful natural phenomena that you

3:56

don't expect but the balance

3:58

between centrifugal force. force and

4:01

gravity gives you these five stable

4:03

points which are very useful.

4:07

So that's it. It's just a

4:09

centrifugal force. Someone's

4:14

going to email us

4:16

a question saying, okay, it's a centrifugal force,

4:18

but how? Why? Let

4:21

me just elaborate a little bit

4:23

further. So if you think of L2, which

4:26

is on the opposite side of the

4:28

Earth from the Sun, one

4:30

and a half million kilometres

4:32

away, that's being pulled

4:36

directly inwards by the

4:38

gravity of the Sun and the

4:40

Earth because they're

4:42

in a straight line. So the two are

4:44

in a straight line. They're both pulling light

4:46

mad with a

4:49

giant gravity. But the centrifugal

4:51

force is trying to push anything at

4:53

that point outwards. Oh,

4:55

right. So yeah, you've

4:58

got a resistance. Yeah, again, just

5:00

got everybody's gotcha. And it's

5:02

pretty way for L3 as well, even though

5:04

that's on the other side of the solar

5:06

system. It's still feeling the gravitational

5:08

pull of both the Earth and the Sun.

5:14

The other two, there a bit.

5:16

I actually find L4 and L5,

5:18

the hardest ones to understand intuitively,

5:21

which Jim was saying are the

5:23

ones you can understand. Because

5:26

we've got a sort of triangle of

5:31

vectors, basically. It's a pull by

5:34

the Earth and by the

5:36

Sun, forming a triangle

5:38

like that. Here's the Sun

5:41

pulling, here's the Earth pulling. So you've got

5:43

to point an object

5:45

at the apex of the two

5:48

vectors, if I can use a technical term, the

5:50

pull. But once again,

5:52

that is balanced by the centrifugal force

5:54

as these things troll

5:56

around the Earth orbit. So it is

5:58

very neat stuff. invented

6:00

by the mathematician who

6:03

probably never thought we'd ever use

6:05

it for practical purposes as

6:08

his name Le Grange very

6:12

good things uh was

6:15

it said no it's Fred Fred Fred

6:17

Le Grange yeah that's it of

6:21

course well you know all the Paul Le Grange

6:23

so called Fred Fred that's

6:27

right thanks for the question Jim

6:30

our next question comes from Kerry

6:33

hi Andrew and Fred excellent podcast keep

6:37

up the great work the following

6:39

has been nagging me for some time

6:41

how is the gravitational effect of supermassive

6:43

black holes and dark matter on galaxies

6:46

separately determined if both are

6:48

impacting a galaxy how is

6:50

the specific mass of a

6:52

supermassive black supermassive black hole

6:54

determined could an incorrect

6:56

estimation of the mass of supermassive

6:58

black holes be the cause of

7:00

the need to include dark matter

7:02

i.e. are the actual masses of

7:04

supermassive black holes big enough to

7:07

cause the gravitational effect that has

7:09

prompted the need to include dark

7:11

the dark matter component looking forward

7:13

to hearing your views and Kerry

7:15

thanks for putting supermassive black holes in

7:17

the question four times all

7:21

right you can get your tongue around that Andrew

7:24

you're already really yeah um

7:27

it is a great question um uh but

7:30

the two are separate

7:33

enough that they can be measured with

7:35

pretty high precision uh separately

7:38

so if you've got a galaxy

7:40

um you you can

7:43

um with a supermassive black hole at

7:46

its center uh and

7:48

if it works best for what

7:50

we call active black holes ones that are

7:52

gobbling up their surroundings so

7:54

there's gas and dust which is whizzing around

7:57

the black hole at relativistic

7:59

speeds speeds close to the speed of light and

8:02

those speeds can be measured. And

8:04

so what you can

8:07

do is actually you

8:09

can sense that

8:12

very close to the black hole

8:14

there is a very high

8:16

gravitational pull and

8:19

that's what the speed of rotation of the

8:21

accretion disk tells you. It tells you that

8:23

there's an enormous gravitational pull. And

8:25

that's really, you know,

8:27

it's far into the centre of the

8:30

supermassive black hole. And that phenomenon, when

8:33

you get, I don't know, even

8:35

only 100 light years away, some supermassive

8:39

black holes, it would be more than that. But you

8:42

don't have to go far away before it

8:44

disappears. So this is very much an effect

8:46

due to the black hole itself. Whereas

8:49

the effect on the galaxy and if you

8:51

take the simplest example, and we've got many,

8:54

many observations of

8:56

a different kinds that tell us that there

8:58

is something missing there, that

9:00

that matter is real. When

9:03

you look at the rotation of the whole galaxy,

9:06

and you look at what would cause

9:09

that the mass distribution that would cause

9:11

that it's not concentrated at the middle,

9:14

you can work out what the distribution of matter

9:16

is by the rotation. And you find that it's

9:18

a blob, which is all around

9:20

the galaxy, but it's quite separate from

9:22

what the black hole measurements are. So

9:25

good question, though. I like it. Yeah.

9:27

Okay. Thank you, Kerry. I hope that

9:29

helped. But yes, there's obvious signs that

9:31

differentiate them is what Fred said, which

9:33

would have been a shorter answer. But

9:36

I've got to

9:38

stretch the program out some more, Andrew.

9:41

Yes, that's true. Thank

9:43

you, Kerry. All right. Our next question,

9:45

which we had to dump last week

9:47

due to time constraints we're going to tackle

9:50

now. This is a what if

9:52

question from Robert. Hello,

9:54

Fred and Andrew. This is Robert from the Netherlands. I

9:57

would like to propose some experiments for

9:59

us. We've made a

10:01

connection with a very superior alien

10:03

race, but because it's

10:05

done through a super-cordant computer, I'll ask

10:08

one question. You two slight gentlemen have

10:10

been selected. So what will it

10:12

be? It can be via within lottery numbers.

10:15

You can ask anything else. I'll just relate

10:17

it to dark energy, big bang, cure

10:21

for aging, have

10:23

a stop time, travel back in time. Anything

10:26

you like, please let me know. I'll

10:30

be listening. Okay, thank

10:33

you Robert. Only one question. I

10:35

did some research on this thread

10:37

and I couldn't

10:40

think of an intelligent

10:42

scientific question to ask.

10:46

And I actually went to one of

10:48

my favorite social media sites, Reddit, to

10:50

see what people would say

10:52

because Reddit people are a little bit

10:54

weird compared to other social media. I

10:57

got a few ideas, but I do remember

11:00

that the Harvard Gazette did actually

11:02

hone in on this via

11:06

our good friend R.V. Loeb.

11:09

And they made a point

11:11

of saying, well, your first stumbling block's going to be

11:13

language. Language is going

11:15

to be the really, the first

11:17

major hurdle to overcome when it comes

11:20

to speaking to another

11:22

interstellar race. And

11:24

I don't know if you've seen the movie Arrival. Arrival

11:28

was a film where these creatures

11:31

came to Earth in their spaceships and sort

11:33

of planted themselves all over the world. And

11:35

they had to get a linguist

11:40

in to try and decipher their language so we could find

11:42

out what they wanted. And of course, Earth being Earth, we

11:44

went on Ready Alert and we're going to blow them all

11:46

up. So there

11:48

was a time limit on how this would be

11:50

resolved. It was very clever film. And

11:53

not only that, it had a

11:55

time element that completely confused

11:57

me until the very end that I went.

12:00

Oh, Danny's plays, all the stories

12:02

are weird. But yeah, that

12:04

was that's the first problem. I

12:07

probably wouldn't ask a scientific question

12:09

straight up. I'd leave that

12:12

to the Fred Watson's of the world. I'd

12:14

want to ask them more rudimentary stuff like,

12:16

you know, how, how

12:19

do you live day to day? What's

12:21

your civilization like? Do

12:24

you have religion? Do

12:27

you, you know, live in houses and have

12:29

streets and get garbage collected? That's the stuff

12:32

I'd want to know. That's exactly what

12:34

goes through my brain. What is their

12:37

lifestyle? Not very scientific. But

12:39

then again, I suppose it is really

12:41

important. And yeah, the sort of thing

12:43

you should ask. Trouble

12:46

is, the answer you might get

12:48

to a question like that could be 42.

12:50

Yeah. Because where

12:56

it goes a bit wonky. I'd

12:59

like to thanks. Sorry, did

13:01

I interrupt you there? Nana.

13:08

Yeah, I mean, in some

13:10

level, I think

13:12

we'd be asking the same question, but maybe framed in a

13:15

different way. Because I would like

13:17

to know, at the

13:20

moment, oh, let me step back a

13:22

bit at the moment, our best understanding of

13:25

reality, the way the universe

13:27

works on big and small scales, is

13:30

the two theories, the two pillars of our understanding

13:32

of the universe. General

13:34

relativity, about things on

13:36

big scales, gravity and all that stuff,

13:39

the ground points, all of that. General

13:42

relativity and, and

13:45

quantum mechanics, which is things

13:48

being in two places at once, and curious

13:50

things like that and things when you look

13:52

at one in one place, you

13:55

immediately know what the other one looks like in the other place.

13:57

So those. Those

14:00

are incompatible and

14:03

a lot of physicists

14:05

in particular have suggested that

14:07

there is a deeper theory,

14:10

some deeper theory that

14:13

maybe quantum mechanics and relativity

14:15

emerge out of. And

14:19

it could be that there

14:21

are things that we simply don't understand at all.

14:23

One is gravity. We know the way

14:25

it behaves because relativity tells us that. We've no idea

14:27

what it is. So

14:30

we postulate, it might be Gramm Itelbs, but we haven't discovered

14:32

them yet. And the other one is time. We've

14:34

got no idea what time is. It's

14:37

sort of, it's a unit in four

14:39

dimensional space time. You can see it

14:41

in the equations. You find

14:43

this term, which is c squared

14:46

t squared coming up in these equations. And

14:48

that tells you that time's a dimension. But

14:51

beyond that, we really don't know much

14:53

about it. And

14:55

so the thinking is that that theory

14:58

that underpins everything

15:01

might explain things like time,

15:03

things like gravity, things

15:05

like why quantum mechanics is

15:07

incompatible with general relativity. And

15:10

it might be, well, it might really be the answer

15:12

to life, the universe and everything. It

15:15

doesn't call the theory of everything. We

15:17

don't have it. So your

15:19

question would be, have you guys figured this stuff

15:22

out? Yes. That's right.

15:24

But where it

15:28

overlaps what you said, they

15:30

might say, yeah, yeah, we have actually, we call

15:32

it religion. You

15:34

know, it's these

15:37

are such deep questions. We really don't know the

15:40

answer to them. And

15:42

so I think I think there's a lot

15:44

of really pointed questions you could ask. Robert

15:47

says we can only have one question. Since

15:49

you two of us, that means we can have two and they might.

15:54

And it's very sad, Robert, to

15:56

have to admit that being humans

15:58

and we get this. contact and

16:00

we can ask one question and the guy

16:02

on Earth at the telescope who receives it

16:04

goes, can you hang on a second?

16:08

Too late, done. That's

16:11

what had happened. Yeah,

16:14

I do agree with you. Arrival was a

16:16

very good movie I really enjoyed. Remo

16:19

film. Most science fiction movies irritate me

16:21

enormously but the wind didn't talk. No,

16:23

no, no, it's so deep, so

16:26

deep, very cleverly constructed film

16:28

and you've got to concentrate.

16:30

You can't go away and

16:33

make a cup of tea because you come back

16:35

and go, what's happened? I

16:37

said, what happened? I can never do

16:39

that, I'm afraid. I lose the track of

16:41

things so quickly, it takes about two milliseconds and

16:43

I've lost the track so I've got to concentrate

16:45

on everything. My

16:47

wife and I'm talking quietly

16:50

because she's just out there. My wife will

16:52

watch a half-hour show after lunch

16:55

and not finish it for three

16:58

or four hours because she keeps stopping it to go

17:00

and do little jobs around the house and that's

17:03

how she spends her afternoon. I'm going to watch

17:05

a half-hour show, start at 12 and

17:08

by the time I'm finished doing these things around the

17:10

house it'll be four o'clock and the show will be

17:13

finished. I think there's

17:15

a lot to be said for that. That's time management,

17:17

isn't it? Yeah, it's time management of the kind

17:19

that I simply don't have. I don't think you

17:21

needed to lower your voice there. I think that was

17:23

a compliment. I hope you're listening Judy. She

17:27

didn't bang on the door or something. Look

17:31

I could go on with ideas about

17:33

this question from Robert

17:35

for forever. There

17:37

is questions just coming to

17:40

mind and you could ask squillions of questions

17:42

and still not scratch the surface about anything

17:46

really but it is a great question and

17:48

one we might get to tackle again further

17:50

down the track. Thank

17:53

you very much for the question. Don't forget

17:56

if you have a question send it into us

17:58

whether it's by audio or text. through

18:00

our website space nuts podcast.com space

18:02

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18:05

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18:07

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always what I've always wanted to do this Click

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18:18

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18:29

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18:31

lights on and you

18:34

know pay Hughes enormous

18:36

salary and And

18:40

Fred that brings us to the end of yet

18:42

another show. Thank you very very much. That's a

18:44

pleasure I'm thinking what's a brined

18:46

up my health a bit Having

18:49

the show because often that's all you need is get

18:52

out of your mind and get out of your misery

18:55

Absolutely, keep yourself occupied and you feel a

18:58

lot better very true. Thanks Fred.

19:00

We'll catch you next week and

19:04

Thanks to Hugh in the studio for reasons that

19:06

don't come to mind but I'm going to get

19:08

the telescope out and ask an alien what he

19:10

does and Until next

19:13

week looking forward to your company

19:15

on the next episode of space

19:17

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