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1:27

Jodrell Bank in Cheshire. I'm here with

1:29

the resident space watcher and professor of

1:31

astrophysics, Tim O'Brien. Hiya, Tim. Hello.

1:35

And the drip-drip that we can hear is actually

1:38

the noise of rain on the tin roof. Exactly.

1:40

It's very unusual to have this sort of

1:42

weather here, my friend. Yeah,

1:44

we can't see that much in the sky tonight, but we will get to

1:46

that. In a bit, we are

1:48

going to be finding out about the celestial origins of Halloween,

1:52

and what you might be able to see

1:54

in the sky on this particularly dark night,

1:57

if it's not completely obliterated by rain

1:59

clouds. Also on today's

2:01

gruesome programme, bloodsucking leeches, the

2:03

horror of pumpkin waste, and

2:05

could zombies ever be real?

2:08

No tricks here, just scientific treats.

2:11

Now, Tim, Halloween has its roots

2:13

in an ancient Celtic tradition that

2:15

I'm not all that au fait

2:18

with, but I understand it has

2:20

some celestial origins too. No,

2:22

I believe so. I think it's the

2:24

Celtic festival. I think it might be

2:26

pronounced Samhain, that is at

2:28

the time of Halloween, and it's one of

2:30

what are called the cross-quarter days, which is

2:32

sort of, you know about equinoxes and solstices?

2:35

Yes. So we had a September equinox, the

2:37

autumnal equinox, basically when, sadly for

2:39

us, the sun sort of passed the equator

2:41

heading into the southern hemisphere. Sad day. So

2:43

it's our winter. But basically,

2:46

between the equinoxes and solstices, you've

2:48

got these cross-quarter days. And the

2:50

one that's roughly between the

2:52

September equinox and the December solstice

2:54

is this ancient Celtic festival

2:57

of Samhain, which is now

2:59

what's become Halloween in modern

3:01

terms. I guess we get

3:03

a lot of that association of festivals

3:05

with their celestial points in time. Yeah,

3:07

I mean, people obviously, in the past thousands

3:09

of years ago, would have been very au

3:11

fait with events in the sky, probably more

3:13

so than modern people are, because of the

3:16

light pollution we have these days. So yeah,

3:18

a lot of these sorts of timings

3:20

of events would have been very familiar with

3:22

people, and they assigned various, you know, traditions

3:25

and things to them. So I think that's

3:27

where Halloween came from,

3:30

via a Christian sort of tradition of

3:33

all souls day and all saints day,

3:35

and eventually Halloween. Are you a Halloween

3:37

fan? Oh yeah, of course. Yeah, particularly.

3:39

I mean, I'm a big horror movie fan, so

3:41

I love the idea of Halloween and all the

3:43

things associated with it. It's a

3:45

particularly spooky setting in this kind of machinery

3:47

shed in George Ralbank. It's

3:49

giving us a really good Halloween

3:52

soundscape. Now, thank you very much,

3:54

Tim, and we will be back with you to talk

3:56

a little bit more about what you might see if

3:58

you look up tonight, a little bit

4:00

better than it is now. But as

4:02

promised we're now going to pay a visit

4:05

to some blood-sucking creatures leeches

4:08

because London Zoo and the freshwater

4:10

habitat trust are working together to

4:12

breed these infamous parasitic worms. Why

4:15

you may ask? Well producer Ella

4:17

Hubert visited London Zoo's leech population

4:19

to find out. First

4:24

box down for everyone so this

4:26

is the oldest bunch they're about

4:28

four months old currently. I'm

4:30

behind the scenes at London Zoo's

4:32

tiny giants exhibit where aquatic species

4:34

keeper Aaron Harvey has just pulled

4:36

out a tub full of wriggling

4:38

baby leeches. Wow

4:43

this is so great. So

4:45

the last time I saw well

4:48

the parents of these guys was

4:50

two years ago. For

4:52

me this is the first time ever seeing

4:54

a leech at all but for Dr Naomi

4:57

Ewald an ecologist with the freshwater habitats trust

4:59

this is the first time seeing the babies

5:01

of the parents she collected two years ago.

5:03

Oh they look so

5:05

beautiful they've got really distinctive

5:08

red running stitch down the

5:10

back. Yeah so in the

5:12

box we have two small moss hides just

5:14

for a bit of land for our leeches

5:17

to kind of wallow in the nice cool

5:19

damp moss. They actually get out.

5:21

Yes. Yeah and that's true in

5:23

the wilds as well. And what

5:25

type of leeches are these? These

5:27

are Hyridimidicinalis and this is our

5:29

native leech and they have jaws

5:32

inside their mouths which have got

5:34

three serrated teeth and

5:36

that's how they feed. There's

5:38

a clue in the name

5:40

of this species of leech

5:42

Hyridomidicinalis. These are medical leeches

5:45

and they have a long history

5:47

in the UK. It's a fascinating

5:49

history in this country and in

5:51

Europe as well. There was sort of

5:53

a leech craze around the 18th 19th

5:55

century for

5:58

using leeches to cure everything. So

6:00

leeches were collected in their hundreds

6:02

of thousands and leech collectors was

6:05

a profession. Unfortunately, obviously, it was

6:07

the poorest paid job because you'd

6:09

go and stand for 20 minutes

6:11

in a pond waiting for them

6:13

to come feed on you and

6:15

then bleed afterwards. And it's that

6:17

bleeding afterwards that makes them such

6:19

an important use for medicine today.

6:21

They are still used in medicine

6:23

today then. This isn't just some

6:25

strange medieval treatment. They are

6:28

very much still used in medicine today.

6:30

They sort of became more popular again in the

6:32

1970s and 80s when

6:35

they realised that this saliva actually

6:37

had multiple benefits. So one, the

6:39

anticoagulant would allow the blood to

6:41

flow. Secondly, they have

6:43

a sort of antihistamine effect. So it

6:45

would bring down the swelling and it

6:47

would stop you feeling when they bit.

6:50

So essentially it would be numb to

6:53

the pain of them biting. So this

6:55

is a fantastic remedy, particularly if you're

6:57

trying to reattach limbs. And

6:59

that's what they're used for in modern

7:01

medicine is to keep the blood flowing

7:03

through those newly attached limbs or fingers

7:06

or skin grafts. But

7:08

actually what's really interesting is the

7:10

ones used in medicine today are

7:12

actually not our UK leech. They're

7:14

a Mediterranean medicinal leech and our

7:17

UK leech is incredibly rare. And

7:20

this brings us to why we wanted to

7:22

partner with London Zoo as part of the

7:24

recovery programme for them. Medical

7:27

leeches are on the brink of extinction,

7:29

a decline which began hundreds of years

7:31

ago and is intimately tied with our use

7:33

of them. Back when they were

7:35

collected for bloodletting, it probably helped them in

7:37

some ways because if you're collecting leeches and

7:40

you're using them and then you're dumping the

7:42

adults back into a name pond, you're helping

7:44

to spread that population around. But

7:47

when that kind of went out of

7:49

fashion and people stopped collecting them and

7:51

a lot of them had been exported,

7:53

that really knocked the numbers back. But

7:55

to just blame collecting is a little

7:57

bit misleading because actually around the same

7:59

time, time there was huge land

8:01

use change in this country. We stopped

8:03

farming in the way that we used

8:06

to, we started to drain fields, we

8:08

lost a lot of our pond habitats

8:10

where these would naturally have occurred and

8:12

so that really started the beginning of the end

8:15

for them. They're also really a

8:17

bit of a glorified worm bless them and

8:20

in modern farming a lot of animals are

8:22

treated with worming treatments and when that passes

8:24

through the system and then into the ponds

8:26

that probably knocked them back as well. So

8:29

of the 150 ponds where we know they

8:33

occur that's really only in four

8:35

locations. We might have to take a quick break

8:37

as one is almost crawled completely out

8:39

of the tub. It's absolutely fantastic.

8:41

It's coming right out and I

8:43

love the way they look around

8:45

and they're obviously sensing because they're

8:47

so sensitive to movement, chemical receptors

8:49

and heat and I imagine it's

8:51

your body heating up. It's the

8:53

body temperature close. Which is really

8:55

cool. The way they move is

8:57

incredible. Yeah it's kind of like dancing

8:59

wavy and it's really elegant actually to watch

9:01

them. Naomi and Aaron could have

9:03

watched the leeches crawling around for hours but

9:06

I had a burning question. How

9:08

does one breed a leech?

9:11

What we do know is that medicinal

9:13

leeches are hermaphrodite so you only need

9:15

two individuals to create the next generation.

9:18

For breeding a leech especially when they're coming out

9:20

of the winter season and their dormancy it's

9:23

that temperature increase that starts to

9:25

trigger their breeding response for the leeches

9:28

to kind of come together and then

9:30

produce their oofica. What's oofica? Oofica.

9:32

So that is their egg sack.

9:34

For the layman if you imagine

9:36

an old-fashioned bath sponge like a

9:38

loofah that's kind of what one

9:40

of these looks like once it's

9:42

hardened. But yeah so the first thing for

9:44

us was to mimic that temperature increase and

9:47

decrease throughout the year. Is the idea

9:49

then to eventually release these

9:51

back into the wild? So

9:53

step number one is to try and look

9:55

after the populations that we have in the

9:57

wild. So these are really a backup. And

10:00

if they won't spread out naturally, we've got

10:02

some parts of the country like Yorkshire where

10:04

they've not been recorded for like 100 years.

10:07

The idea would then be at the

10:09

right time and once we know enough

10:11

about what we're doing we'll be able

10:14

to re-release them back into the world

10:16

and increase the population again. I

10:18

have one more box as well. Oh have you?

10:20

I'll show you these ones. So in the second

10:22

box we have slightly

10:25

younger ones. Oh aren't they wonderful,

10:27

look at that. They're so adorable.

10:29

Aren't they just perfect? Wonderful, adorable

10:31

and perfect are not words I

10:34

would have ever used to describe

10:36

a leech before though Naomi

10:38

and Aaron's passion was certainly infectious.

10:41

But the need for recovery program

10:43

for medicinal leeches goes beyond just

10:45

an appreciation for the species. So

10:48

you could look at it in two ways. One, I

10:51

think that every creature intrinsically has a

10:53

value and that we should make sure

10:55

we conserve them for future generations. The

10:58

second argument would be that they are

11:00

part of a food chain so things

11:02

eat them and they eat things but

11:05

also they're a really good sign of

11:07

a healthy habitat. Wherever you've got medicinal

11:09

leeches you know that you've got a lot

11:11

of other wildlife as well so they're almost

11:13

like a canary of the pond world. If

11:15

we can get it right for them then

11:18

we can get it right for everything else.

11:20

To keep our native wildlife happy we have

11:22

to keep our leeches happy. It's

11:24

understandable if you're still wary of

11:26

leeches at the end of this.

11:28

I have to admit that I

11:30

still am but their long history

11:32

in medicine, their role in our

11:34

freshwater ecosystems and their fascinating

11:37

little lives are undeniable.

11:39

So thank you to Aaron Harvey and

11:42

Naomi Ewald for giving me a glimpse

11:44

into that wonderful world. Thank

11:47

you to our very own very brave Ella

11:50

Hubber there. You

11:52

are listening to a particularly spooky and

11:54

slightly soggy Inside Science with me Victoria

11:56

Gill and if you have a fiendishly

11:58

curious science question for us please

12:01

do send it in by Raven if

12:03

possible or just by email to

12:05

inside science at bbc.co.uk. Now

12:07

Tim are you going to be going trick-or-treating this year?

12:11

I think not this year I'm afraid I'm a bit

12:13

of a yeah but it was sort of well away

12:15

from the neighbors really so it's a bit hard to

12:17

do that yeah. Yeah it's difficult if you've not got

12:19

people's doors to actually knock on. So at

12:22

the moment what are you studying at

12:24

Jodrell because Jodrell is much more about

12:26

listening we just walked by the beautiful

12:28

Mark 2 telescope this gorgeous dish that's

12:30

pointed at a particular angle what are

12:32

you listening for at the moment? We're

12:34

actually right this minute we're collecting

12:36

radio waves from a stellar

12:39

explosion that happened about 2.4

12:42

billion years ago so it's 2.4 billion

12:44

light years away it's called

12:46

the gamma ray burst an incredibly bright one the brightest

12:48

one we've ever seen and for that reason rather

12:51

unusually goes by the name of the boat

12:53

as in you know the greatest of all

12:55

time this is boat brightest of all time.

12:57

How are you studying

13:00

that? We're actually linking this telescope up which

13:02

is part of the e-Merlin network so I

13:04

can't offer you a witch but I can

13:06

offer you a wizard so Merlin

13:08

is a network of telescopes around the UK but

13:11

we're linking those up with telescopes

13:13

right the way across Europe and

13:16

also a whole network that's spread across

13:18

the USA from Hawaii to

13:20

Puerto Rico and another network that's

13:22

in Australia and with that we're

13:24

creating a radio telescope that's effectively the size of

13:26

the whole planet. So almost like an

13:29

enormous dish that's just that's like taking in

13:31

all of that data the kind of the

13:33

most intense signal that you could get? Yeah

13:36

yeah and the real power of it is

13:38

that by spreading these telescopes far apart so

13:40

you know as far apart as the diameter

13:42

of the planet then you

13:44

actually get a sort of zoom lens effect you

13:46

see the fine detail when you make the images

13:48

of these radio objects in the sky you see

13:51

very fine detail and we really need to do

13:53

that with an object like this because it's so

13:55

far away it's going to be very very small

13:57

on the sky. And the wonderful thing

13:59

is you can actually see through the

14:01

clouds with radio waves. So you

14:03

don't need the weather to clear up. That is the

14:06

great way. We probably wouldn't be here in lovely

14:08

sunny Cheshire if

14:10

we couldn't do that. Yeah, radio tar scopes, that's

14:12

the power we can observe through the clouds. We

14:15

can observe during the day as well as at night. And so it's

14:17

really a 24-hour operation here. Working

14:22

through the nights, even on Halloween. Thanks,

14:24

Tim. Now,

14:27

here's a disturbing question. Could

14:29

zombies walk amongst us? Frank

14:32

Swain has been looking into the science

14:34

of the undead. When

14:44

the folklorist Laffcadio Hearn went searching for

14:46

zombies in the Caribbean island of Martinique

14:49

in 1889, he

14:51

found them curiously difficult to pin down.

14:55

A zombie, one young woman told him, was

14:58

an uncanny and unsettling event, a

15:00

three-legged horse passing in the road, or

15:03

a great fire at night that recedes into

15:05

the distance as you approach it. It

15:09

was only when US troops occupied Haiti in 1915,

15:13

bringing with them the return of forced labor, that

15:16

the zombie coalesced from an unsettling

15:18

idea into a tangible calamity. A

15:22

zombie was henceforth a pitiful creature,

15:25

one raised from the dead and enslaved

15:27

by a malign authority. But

15:30

if Hearn had instead turned his attention

15:32

to the natural world, he would

15:34

have found endless examples of real-life

15:36

zombies, every bit as terrifying

15:38

as one of his ghost stories. The

15:41

beautiful emerald wasp, for example, stupefies

15:44

a cockroach with a sting to its brain,

15:47

turning it into a docile living larder

15:49

for the wasp's hungry young. Crickets

15:52

laden with aquatic horsehair worms

15:55

find themselves compelled to leap into

15:57

ponds of water, where they drown,

16:00

releasing the worms inside. And

16:03

mosquitoes infected by malaria are

16:05

induced to starve themselves until

16:07

a protozoan inside is fully

16:09

developed. Why risk your

16:11

host being swatted before you're ready to be

16:13

passed on? There

16:15

is no evidence that we are immune from

16:17

this kind of microbial meddling. Meet

16:20

toxo. The single-celled toxo

16:22

palasma gondii is common in mice,

16:25

but can only complete its life

16:27

cycle inside a cat. To

16:29

get from one to the other, toxo

16:31

will rewire the mouse's brain,

16:34

turning it into a thrill-seeking,

16:36

if slow-witted rodent. The

16:39

host's new livefast, die young attitude

16:41

soon delivers it into the belly

16:43

of a passing cat. Toxo

16:46

can also live inside humans, and

16:49

seems to treat us as an especially large

16:51

mouse. Czech researcher

16:53

Jaroslav Lega found that

16:55

people carrying the microbe have slower reaction

16:58

times, and a study at

17:00

a Prague hospital found those responsible

17:02

for car accidents were two and

17:04

a half times more likely to

17:06

test positive for toxo than the

17:08

general population. Around

17:10

half of Brits show evidence of toxo

17:13

infection by age 50. Just

17:16

as well there are no big cats stalking the

17:18

streets of London, or we might be in

17:20

real trouble. Benjamin

17:23

Franklin famously said that nothing in

17:26

life was certain except death and

17:28

taxes. And so far there's

17:30

no sign that nature has found a way to raise

17:32

the dead. Yet in 1929, reports

17:36

surfaced that Soviet scientist Sergei

17:38

Bryokanenko had used his autojector,

17:41

a kind of primitive heart-lung

17:43

machine, to do just that.

17:46

Films shot in his laboratory

17:48

shows dogs, or rather just

17:50

their heads, kept alive by

17:53

a whirring contraption of glass vials

17:55

and rubber tubes. The

17:57

film culminates in the death and then

17:59

minuscule. later resurrection of a small

18:02

brown dog. Briokarenko

18:04

even claimed his machine had

18:06

successfully revived a human test

18:08

subject. While his

18:11

results were no doubt sensationalized, such

18:13

work helped build the foundation of

18:16

emergency medicine that today has

18:18

returned millions of patients from the brink

18:20

of death. And

18:22

while we can't raise the decidedly dead,

18:25

some still choose to have their

18:27

remains cryogenically frozen in

18:29

hopes that one day, reanimation science

18:31

will succeed. Be

18:34

warned though, some early

18:36

patients were unceremoniously thawed out and

18:38

disposed of when they fell behind

18:41

on maintenance payments to the cryonics

18:43

firm. Proof that

18:46

even if death isn't certain, there

18:48

will always be taxes. Thank

18:57

you very much to Science Writer and author

18:59

of How to Make a Zombie, Frank Swain.

19:02

Finally, to this celebration's iconic

19:04

fruit, the humble pumpkin.

19:07

You may have visited a pumpkin patch to pick

19:09

your own this year, or perhaps you're carving and

19:11

decorating one as I speak. But

19:13

what happens after Halloween? I

19:16

spoke to Dr. Alice Brock, who's been

19:18

looking into the environmental horrors of pumpkin

19:21

waste. I started by asking her,

19:23

just how many pumpkins are thrown away each year?

19:26

So it's about 18,000 tons of pumpkins, maybe

19:29

around about 13 million pumpkin

19:32

are going to landfill. They think it

19:34

could be kind of 27 million pumpkins

19:36

are being purchased. It's kind of hard

19:38

to estimate because every pumpkin weighs slightly

19:40

differently, but it is about

19:42

18,000 tons of pumpkins going into

19:44

waste. And how much

19:46

of a problem is that? I mean, they'll

19:49

just buy a degraded way, won't they? So

19:51

the problem is actually that. What

19:53

happens is when food waste goes

19:55

into landfill, it will

19:58

biodegrade, but it degrades anaerobic.

20:00

so it's not using oxygen. It's trapped

20:02

in plastic bags under other rubbish and

20:04

that produces methane. Methane is 25 times

20:07

as potent as carbon dioxide in terms

20:09

of its global warming potential so a

20:11

ton of carbon dioxide compared to a

20:13

ton of methane, that methane is 25

20:16

times as bad for the planet in

20:18

terms of warming. So why

20:20

is it going into landfill rather than

20:22

compost? Do we have a good measure

20:24

on just how much? Because it sounds

20:26

like the problem is landfill rather

20:29

than the degradation process or

20:31

is it what happens when these pumpkins go

20:33

into a compost heap? So

20:35

composting will release a little bit of

20:38

kind of greenhouse gases but it's not

20:40

as bad. There have been studies that

20:42

have kind of compared these things. Composting

20:44

doesn't have as high a kind of

20:46

global warming potential because it's

20:48

a different kind of process. So

20:51

when it goes into landfill it's particularly problematic

20:53

because of the environment it's in. It's also

20:55

contributing to landfill gas which is mostly methane,

20:58

about 60%. So all of those

21:01

pumpkins going into landfill, do

21:03

we have a measure on

21:05

how much greenhouse gas comes

21:07

from that? Yeah so I can give you the numbers

21:09

on food waste and I don't have

21:12

exact pumpkin figures because it turns out there aren't

21:14

that. I was like this is

21:16

a whole area of research I'm now gonna

21:18

nag my colleagues that we should go and

21:20

do. But a ton of food waste according

21:22

to Dephra is about 627

21:25

kilograms of carbon dioxide equivalent. So

21:27

carbon dioxide equivalent is the unit we use for all

21:30

kind of greenhouse gases. So if we consider our 18,000

21:32

tons of pumpkins that's about 11,200 tons of carbon dioxide

21:34

equivalent. So

21:38

if you look at your pumpkin around about 60% of

21:41

that is then going to become

21:43

a greenhouse gas when it goes into

21:45

landfill essentially. Right more than

21:48

half of your pumpkin is going to be

21:50

transformed into a planet warming gases

21:52

if it goes into landfill. Yeah

21:54

I mean essentially. Right and what about

21:56

the resources that it takes to grow

21:58

each of those? pumpkins? Yeah,

22:02

I mean a pumpkin itself actually

22:04

isn't that bad. You know most

22:06

vegetables compared to say meat, fairly

22:08

low-carbon, it's the fact that it's

22:10

then going to landfill, it's that kind of waste aspect

22:12

that's the real problem when it comes to pumpkins. And

22:15

they're not necessarily going into food

22:17

waste. Now some local councils

22:19

don't collect food waste, in my city they

22:22

don't currently, that is going to change by

22:24

2026. But at the moment it might be

22:26

that people

22:28

can't put it into a food waste bin.

22:31

I kind of think it might just do because pumpkins

22:33

are really big. So you might kind of

22:35

go, oh I guess I've got to put this in general

22:38

waste. It might be something as straightforward as that. It might

22:40

that you're just thinking of it differently

22:42

because it was kind of a decoration. Yeah,

22:45

you're not eating it so you're not thinking of it as

22:47

food. I mean my food waste bin is

22:50

probably not big enough for our pumpkin. It's

22:52

really quite small. So what about just,

22:54

are there other ways to dispose of

22:57

it? The best thing to do with

22:59

a pumpkin is to just eat it.

23:01

It's food, you could just cook it

23:03

and then we don't have any of this problem

23:05

at all because suddenly it's not actually in that

23:08

waste stream anymore at all. Okay, so does

23:10

that change how we should be treating

23:12

pumpkins then? So you wouldn't necessarily suggest

23:15

that we just just we should stop

23:17

picking and carving pumpkins decoratively for Halloween

23:19

but that we should treat them as

23:21

food as well as decorations? Oh definitely.

23:24

I mean if you're kind

23:26

of looking at this from a sustainability

23:29

perspective that the social side of pumpkins

23:31

at Halloween, massively important. You

23:33

can still do all of the

23:35

messy fun bit, you can still carve it,

23:37

you can still decorate it and then you

23:39

could just roast it or

23:42

you can turn it into my colleague makes

23:44

really good pumpkin blondies. You know it is

23:46

food, it's still something that we can get

23:48

nutrition from. Okay, so talk

23:51

me through a more sustainable and

23:53

still fun Halloween journey with your

23:55

pumpkin. So I mean some people don't

23:57

even cut up the pumpkins, you could just leave it as

23:59

a a nice decorative pumpkin, that's not

24:01

very fun. You might want

24:04

to kind of just not cut it so you've

24:06

not got like exposed bits to the air and

24:08

you know maybe do something like edible paints. I've seen

24:10

people do that. It can look really, really cool. You

24:13

might want to still carve it but then

24:15

only have it out very briefly, sort of

24:17

in the evening and

24:19

then put it in the oven, which

24:22

I think would probably be quite a horrifying Halloween

24:24

experience if you've given it a face. Sounds

24:27

quite fun. A sort of carved Halloween

24:29

feast. Yeah, so once you've roasted your

24:32

pumpkin you can either eat it roasted

24:34

or pumpkins can be used in all

24:36

sorts of recipes. As I said,

24:38

you can make pumpkin blondies. There's always things

24:40

like pumpkin pie. There's a ton of different

24:42

foods once you start looking into it. So

24:44

it's just sort of rethinking a little bit

24:46

like what you're doing with this thing. And

24:49

yeah, don't put a candle in it because that's

24:52

not going to be good for human consumption

24:54

if you've burnt a candle in it and

24:56

don't put it outside. You can still

24:58

do sort of something with it and then

25:00

eat it. Thank you

25:02

very much to Alice Brock there who's

25:04

from the Sustainability and Resilience Institute at

25:06

the University of Southampton. I am definitely

25:08

going to be looking at my pumpkin

25:10

in a different and hopefully delicious way,

25:12

although I've got to admit I am not a very good cook.

25:15

But if you have any recipe

25:17

suggestions for your Halloween leftovers please

25:20

do get in touch at insidescienceatbbc.co.uk.

25:23

I'm still here with Professor D'Arcy and Professor

25:25

Tim O'Brien at Jodrell Bank, hunkered under the

25:27

tin roof of a machinery shed. But we

25:29

can see a little bit of sky, but

25:31

it's looking pretty cloudy. You're not going to

25:33

be able to see very much tonight. But

25:35

at this time of year, are there

25:38

astronomical events that we could be looking out

25:40

for? Yeah, I mean, it's very

25:42

appropriate actually that this is what we call

25:44

dark time in astronomy at the moment. What

25:47

does that mean? It's very sought

25:49

after by visual astronomers. So astronomers who use optical

25:51

telescopes because it's when the moon is quite close

25:53

to the sun. So as the moon orbits the

25:55

earth, it's sort of sometimes it's very near the

25:58

sun at the time of the new moon. moon

26:00

and then other times it's on the other

26:03

side so full moon so now we're near

26:05

new moon which means that the moon's not

26:07

up during the night and therefore the dark

26:09

the very dark skies so anybody who wants

26:11

to study faint objects would be interested in

26:14

using a telescope around the time of dark

26:17

time yeah but yeah

26:19

if we have clear skies it's a great time

26:21

of year for if you look straight up you'll

26:24

see Cassiopeia it's a classic W shaped

26:26

constellation or M shaped. You need to

26:28

know your Greek mythology don't you? so yeah

26:30

actually my Greek mythology is a little bit

26:32

pitiful probably a lot less good than yours but but

26:35

yeah I'm vaguely aware of who's related to

26:37

who what's the story of Cassiopeia? Yeah she

26:39

was the mother of a

26:41

vandromedo the princess that they decided to

26:44

sacrifice to a sea monster called Cetus.

26:46

These are all constellations

26:49

and she was saved by Perseus who

26:51

had gone and sliced off the head

26:53

of Medusa you know the snake-headed Gorgon

26:56

and he then flew in

26:58

on the winged horse Pegasus

27:01

and he flew in and sort of saved and

27:03

saved Andromeda but all these constellations are basically up

27:06

in the in the night sky this time of

27:08

year and one of my favorite sort

27:10

of Halloween-y things about those constellations

27:12

is that in Medusa's head which

27:14

Perseus is holding in the in

27:16

the in the night sky in

27:18

that sort of Greek constellation picture

27:21

the eye of Medusa is a

27:23

star called Algol which is an

27:25

Arabic word for algul as in

27:27

goo the demon the sort of

27:29

demon star and this

27:31

eye winks so every 2.8 days or so

27:34

it goes down in brightness by

27:37

a factor 3 or something because it's actually

27:39

a star that has a binary system

27:41

in it where one star goes

27:43

in front of the other and it blocks

27:45

out the bright star and so it very

27:47

noticeably even just to the the unaided eye

27:49

it dips in brightness significantly so the the

27:52

eye of the Gorgon Medusa winks the algol

27:54

the demon star and that's over the head

27:56

of that's amazing so whereabouts in

27:58

the night sky should we look for the

28:00

eye of the Gorgon. Yeah what I would

28:02

I mean if you can find the W

28:04

of Cassiopeia, it's a classic sort of W

28:06

shape, then below that you see Perseus and

28:08

to the right of that if you like

28:10

if you're looking at that is the head

28:12

of Medusa. I mean I would recommend getting

28:14

hold of one of these, I'm a fan

28:16

of free apps, I'm not saying I'm tired,

28:18

I'm tired or anything but there's a very

28:20

good one called Stellarium which

28:23

I would recommend downloading. To

28:25

give you a guide of what you're looking at. It'll give you

28:27

a guide of exactly where you are, they're really handy for

28:29

that sort of thing if you want to find the exact

28:31

position of this star. Well Tim thank

28:33

you so much for coming out on

28:35

this slightly gloomy evening. We didn't get

28:38

much of a night's guide did we

28:40

but I will be looking out for

28:42

the Gorgon's blinking eye. Thank you so

28:44

much Tim O'Brien. No problem. You've

28:46

been listening to BBC Inside Science with

28:49

me the ghoulish Victoria Gill, the producers

28:51

were the haunting Ella Hubba, the sinister

28:53

Sophie Ormiston and the horrifying Jerry Holt.

28:55

Technical production was by the menacing Kath

28:58

McGee and the show was made in

29:00

Cardiff by BBC Wales and West. And

29:02

away from the overworked Halloween adjectives if

29:05

you want to discover more fascinating science

29:07

content head to bbc.co.uk search for BBC

29:09

Inside Science and follow the links to

29:11

the Open University. Until next

29:14

time from the rainy gloom

29:16

of darkest Cheshire thanks for

29:18

listening and mwahaha.