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this. This

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is a CBC Podcast. Hi,

0:38

I'm Bob McDonald. Welcome to Quirks and

0:41

Quarks. On this week's show, one

0:44

species' feces is another one's

0:46

treasure. But this treasure

0:48

might be poisoned. We saw

0:50

many instances of chimps coming, black

0:53

and white colobus monkeys and

0:55

red diker. And they were all coming to

0:58

feast on this bat poop. And

1:01

five million years ago, a gigantic

1:03

salmon with tusks swam the seas

1:05

of the Pacific. They actually look more

1:07

like a warthog. Some people describe them almost

1:09

looking like a mustache. Looks like

1:11

they could have been spikes and used for tools.

1:14

Plus desperate measures might be

1:17

working for woodland caribou, the

1:19

Gulf oil spill and the fish we don't

1:22

see. And why

1:24

tiny black holes might be spinning through our

1:26

solar system. All this today on

1:29

Quirks and Quarks. A

1:32

few years ago, researchers working

1:34

in the lush tropical Budongo

1:37

rainforest in Uganda saw something

1:39

peculiar. A group of

1:41

chimps were huddled together at the base of a

1:43

big hollow tree. They were

1:45

reaching in and retrieving something that they

1:47

were then eating. And

1:49

upon closer inspection, what they were

1:51

eating was kind of nasty. It

1:54

was bat poop. Apart

1:56

from the obvious ick factor, it

1:58

made the researchers wonder. wonder why were

2:00

they eating it and what

2:02

were they being exposed to? Bats

2:05

are known to be carriers of

2:07

several nasty pathogens that can spread

2:10

to other wildlife and to humans.

2:12

So they recruited some epidemiologists

2:14

and began to investigate, and what

2:16

they found could have an impact

2:18

on our understanding of how diseases

2:20

escape wildlife into the wider world.

2:23

Dr. Tony Goldberg is a professor of

2:26

epidemiology in the School of Veterinary Medicine

2:28

at the University of Wisconsin-Madison. He was

2:30

part of the team. Dr.

2:33

Goldberg, welcome to Quirks in Quarks. Thank you for

2:35

having me. Now tell

2:37

me about these chimps eating bat poop

2:39

or bat guano. Is this a new

2:42

behavior for them? This

2:44

is a new behavior and you're right, ick.

2:47

When we first saw this a few

2:49

years ago, we had never seen it before, so

2:52

that's despite the fact that these chimps have been the

2:54

subjects of research for decades. So if they had been

2:57

doing it, we would have noticed. So

2:59

what do you do to try to understand this

3:01

behavior better? We thought

3:03

about it and we realized that chimpanzees

3:06

have a problem that they have to

3:08

solve on a daily basis. Where do

3:11

you get your minerals? And in forests

3:13

like Budongo in Uganda, natural sources that

3:15

are rich in minerals are rare. So

3:18

we thought, aha, maybe they're doing

3:20

this because they're in search of

3:22

minerals in their diet. Now

3:25

were the chimps the only animals doing this

3:27

or were other animals also attracted to the

3:29

bat poop? Over several months,

3:31

we saw many instances of

3:33

chimps coming, black and white

3:35

colobus monkeys and red

3:38

diker, a kind of small cute forest antelope.

3:40

And they were all coming to

3:42

feast on this bat poop. So

3:45

why would these animals decide to eat

3:47

bat poop? So we knew

3:49

from decades of research at this site

3:52

that animals eat weird things in

3:54

their pursuit of minerals. The

3:58

question that really got us interested though is why

4:00

did they just start doing this now? Chimpanzees

4:02

and other animals have their

4:05

preferred sources of natural dietary

4:07

minerals. One of those sources,

4:09

its scientific name is Raffia

4:11

farinifera, and it used

4:13

to be very abundant in this

4:15

environment. And when that tree died,

4:17

the rotting inner pith of the

4:19

tree was very rich in sodium

4:22

and other minerals, and chimpanzees loved

4:24

it. About 20

4:26

years ago, that tree all

4:29

but disappeared in Budongo. There was a

4:32

demand in the area for

4:34

the leaves of that tree to

4:36

make strings for drying

4:38

tobacco leaves that were

4:40

produced during tobacco farming.

4:43

And these animals lost dietary minerals, so

4:45

they had to find something else. And

4:49

that's when we started to see them eating guano,

4:51

which is rich in the minerals that they used

4:53

to get from this tree. Well,

4:56

how were they able to eat the bad

4:58

feces and not get horrendously sick to the

5:00

stomach? We have all wondered that.

5:03

I get horrendously sick to the stomach just

5:05

watching them eat the bad guano. All

5:07

I can say is that these

5:09

animals naturally eat

5:12

soil. It's a

5:15

behavior that we call geophagy. And

5:18

it's not too much of a stretch to

5:20

go from eating soil to eating a pile

5:22

of something that looks like soil. Well,

5:24

what minerals are the chimps getting

5:27

from the bad poop? They are

5:29

getting a lot of phosphorus, also

5:31

calcium and magnesium. They're getting sodium.

5:34

Not as much as we thought,

5:36

but phosphorus, magnesium, calcium, and sodium

5:39

are pretty essential elements for

5:41

a diet. Okay,

5:44

so if it's so nutritious, why

5:46

is it concerning that the animals are eating

5:48

these feces? It's

5:51

concerning because we know something else

5:53

about bats. We also know

5:56

that bats carry interesting and

5:58

sometimes dangerous animals. pathogens.

6:01

We think that bats are the

6:03

source of coronaviruses, many coronaviruses that

6:06

have caused outbreaks in humans like

6:08

the SARS coronaviruses. So

6:10

did you find any of those pathogens in

6:12

the bat guano? We sure did.

6:14

We found 27 viruses

6:17

in this bat guano. Two-thirds

6:19

of them are things you'd

6:21

expect to find in insects because

6:23

these bats are eating insects, so

6:25

that wasn't surprising. We found some

6:27

fairly obscure viruses of mammals, but

6:30

we also found something surprising,

6:33

a first cousin relative to

6:35

SARS coronavirus too. Wow.

6:38

Now are the chimps showing

6:40

any signs that they're getting

6:42

the coronavirus? They

6:45

are not. So we have not

6:47

seen chimps eating this

6:50

guano and then getting something that

6:52

looks like a coronavirus disease. That

6:54

being said, chimps in the wild

6:56

do get sick and they do

6:58

get respiratory infections, but they're rarely

7:00

diagnosed, so we rarely have the

7:02

opportunity to know what they're infected

7:04

with, but it's plausible. So

7:07

why might this be a problem for human health?

7:10

We think that a lot

7:12

of human epidemics and maybe

7:15

even pandemics begin in

7:17

wildlife. This is not a new

7:19

idea. We've seen this with

7:22

Ebola, for example. There's

7:25

decent evidence that some human

7:27

Ebola virus outbreaks begin

7:30

when animals in the forest get

7:33

Ebola die and then humans touch the

7:35

carcasses. And another thing

7:37

that we realized when we first saw

7:39

this behavior is that three of the

7:41

animals that have been implicated as

7:45

hosts in Ebola outbreaks are

7:47

chimpanzees, black and white colobus, and dyker,

7:49

which are the same three animals we

7:52

saw eating the bat poop. Well

7:54

what does this mean for our understanding

7:56

of how viruses can spread from bats

7:58

to other animals? and then eventually to

8:01

us. It's sort of a

8:03

missing link because it was

8:05

never clear how these sorts

8:07

of chains of events happen

8:10

in nature. Well, how could knowing

8:12

about this missing link help us

8:14

prevent future disease outbreaks? I

8:17

can't help but think, what

8:19

if the solution to

8:22

the potential problem of

8:24

these animals being exposed to bat viruses

8:27

was as simple as giving farmers a

8:29

ball of twine so they

8:32

didn't have to cut down this tree and

8:34

dry their tobacco leaves. What

8:36

an incredibly inexpensive and

8:38

simple solution to this problem.

8:41

Just another amazing example of

8:43

the unintended consequences of human

8:46

activity. Exactly. Dr.

8:50

Goldberg, thank you so much for your time. You

8:53

are very welcome. Dr. Tony Goldberg

8:55

is a professor of epidemiology at

8:57

the School of Veterinary Medicine at

8:59

the University of Wisconsin-Madison. Caribou

9:12

are an iconic Canadian animal with

9:14

a long history in our landscape,

9:17

but they also have a long history

9:20

of struggling when humans encroach on their

9:22

habitat. The Southern

9:24

Mountain Caribou of British Columbia

9:26

and Alberta are particularly vulnerable.

9:29

They live in small groups and

9:31

need large undisturbed swaths of old-growth

9:34

forest in order to survive. Conservation

9:38

groups started rallying to protect these Caribou back

9:40

in the 1950s, but decades of

9:44

half-measures did nothing, and

9:46

populations still continued to decline.

9:49

So in recent years, scientists have been

9:51

trying anything and everything to save these

9:53

animals from long-term programs

9:56

like habitat restoration to

9:58

short-term strategies that seem extreme,

10:01

like captive breeding programs, penning

10:04

mothers and offspring to keep them safe

10:07

and even killing predatory wolves. And

10:10

in a new study, they've looked at which, if

10:12

any of these measures, is working and

10:14

whether caribou were really better or worse

10:16

off as a result. Dr.

10:19

Clayton Lamb is a wildlife scientist

10:21

at Biodiversity Pathways and the University

10:23

of British Columbia, Okanagan. He led

10:25

the study. Dr. Lamb,

10:27

welcome back to our program. Thanks for having

10:29

me today. First of all,

10:32

tell me about these caribou. Most

10:34

of us are familiar with the caribou and the high Arctic.

10:37

What are these mountain caribou like? So

10:40

in British Columbia and Alberta, especially in

10:42

the southern half of the provinces, there's

10:44

a special type of caribou called a

10:46

mountain caribou. And these are caribou

10:48

that basically live up in the mountains of

10:50

the Rockies and the Purcell's and the Selkirk's

10:53

and they eat arboreal lichen,

10:55

so the lichen in trees and also

10:57

the lichen found along the ground. And

11:00

these are animals that migrate up and

11:02

down the slopes as opposed to these

11:04

far distances like we see in the

11:06

Arctic. Oh, so they stay within the

11:08

Rockies? Yeah, exactly. They actually

11:10

typically stay in fairly small areas, sort

11:12

of distinct herds right now, partly due

11:14

to how few there are left, but

11:16

they don't move nearly as far as

11:18

the high Arctic animals. Now, why

11:21

is it so challenging to keep their

11:23

populations healthy? Yeah,

11:25

so southern mountain caribou are one

11:27

of the most challenging conservation issues

11:29

that Canada has right now. So

11:31

their populations have declined dramatically over

11:33

the last 50 years or

11:35

so. And it really comes down

11:37

to a landscape that's just not working for these

11:39

caribou. The landscape has

11:42

been transformed from industrialized resource extraction,

11:44

so logging, which has basically produced

11:46

a landscape that is more attractive

11:49

for deer and moose. And

11:51

that's not necessarily a bad thing in that that can

11:53

be good for hunters and it is good for

11:55

deer and moose, but it brings in wolves.

11:58

And caribou basically... struggle to

12:00

coexist with high predator densities. And

12:02

those wolves prey on

12:05

caribou on sustainable race and have

12:07

precipitated very dramatic declines of caribou

12:09

populations across southern Canada. Well,

12:11

when you say dramatic decline, how much have

12:13

their populations gone down? By

12:16

over 50% in the last 30 years,

12:19

and a number of those distinct

12:21

herds have actually been completely lost.

12:23

So they've gone to zero and

12:25

the actual distribution of caribou is

12:27

shrinking quite dramatically. Wow. Take

12:30

me through some of the interventions that are being used

12:32

to help save the caribou. Yeah,

12:35

so there's a number of interventions

12:37

that are being used to keep

12:39

caribou on the landscape while habitat

12:41

restoration and protection is underway. And

12:43

the important thing there is to

12:45

sort of create a landscape that

12:47

works for caribou could take decades.

12:49

And so in that interim period,

12:51

we need to keep caribou around.

12:53

And those interventions are

12:56

largely focused on reducing this unsustainable

12:58

predation on caribou. And so

13:00

they range from maternal pens, which

13:02

is bringing caribou into sort of

13:05

a high elevation enclosure where they would sort of

13:07

naturally be at that time of year to have

13:09

their calves and safety. Some

13:11

of the other actions are reducing

13:13

the density of wolves. So, you

13:15

know, because this landscape has been

13:17

so dramatically transformed, the density of

13:19

wolves is much, much higher than

13:21

caribou historically co-existed with. So

13:24

there is the direct removal of wolves

13:26

and then also other ways to reduce

13:28

wolves through reducing the number of moose,

13:30

which eventually should reduce the density of

13:32

wolves. So, you know, people are trying

13:34

all sorts of different things, including also

13:36

feeding caribou and just trying to keep

13:39

these caribou around as best as they

13:41

can using the tools that we have in hand.

13:44

And what did you find? What we found

13:46

was that since 1990s,

13:48

the population of Southern Mountain Caribou has declined

13:50

quite dramatically by over 50%. So in the

13:52

1990s, there was around 10,000 caribou.

13:54

And today

13:58

there's just shy of 5,000. But

14:01

we did find that those recovery measures

14:03

that were applied have increased the population

14:05

by quite a bit, by over 1,500

14:07

animals compared to what would have been

14:09

here otherwise. And what

14:12

is really working for caribou is

14:14

the reduction of predators. So the

14:17

reduction of wolves and additional recovery

14:19

interventions that are supporting the recovery

14:21

of caribou on top of the

14:24

wolf productions are maternal penning, so

14:26

to keep those calves safe and

14:28

feeding caribou. So

14:31

would you consider the programs a success

14:33

then? I mean

14:35

from a caribou perspective and from

14:37

the perspective of trying to keep

14:39

caribou around and averting the loss

14:41

of those herds, yes, the wolf

14:44

reductions and the remainder of the

14:46

restoration or recovery actions that were

14:48

applied have avoided the excavation of a number of those

14:50

herds. Now we've

14:53

talked on this program a lot about the importance

14:55

of predators in an ecosystem. Are

14:58

you concerned that these

15:00

interventions of reducing the number of predators

15:02

could have other problems in the ecosystems?

15:05

Yeah, I think we have to consider that. I

15:07

mean we don't want to sort of trade one

15:10

problem for another. You know I

15:12

think we are seeing some shifts in

15:14

the landscape and the composition of species

15:16

on it and I think we have

15:18

to keep our mind to what the

15:20

additional ecological consequences could be. From

15:23

the wolf perspective, generally the wolf

15:25

density is brought quite low, like

15:27

the target is less than three

15:29

wolves per thousand square kilometers and

15:31

it generally quickly rebounds after they

15:33

are reduced due to dispersal from

15:35

outside the area. So there usually

15:38

remains some wolves in these areas

15:40

but not as many as there

15:42

were previously. Why

15:45

is it important to protect the caribou to

15:47

this extent? Well

15:50

in this case it's sort of this

15:52

binary option of if we don't protect

15:54

them, they will be lost.

15:57

There are a number of these herds that have already

15:59

been... been completely lost before these

16:01

interventions took place. And if

16:05

the interventions that did take place weren't

16:07

done, a number of the other herds

16:09

would have been lost. And so we're

16:11

essentially in the situation where we either

16:13

act to keep caribou on the landscape

16:15

or they will rapidly not be in

16:17

British Columbia and Alberta. It

16:20

does speak to the larger vision here

16:22

though that this is an interim action

16:24

and we don't necessarily want to be

16:26

solely sustaining a caribou population off these

16:29

interim actions. They are expensive,

16:31

they have ecosystem and ethical

16:33

concerns, especially on the wolf

16:35

cull side. And this

16:38

is an intervention to stave off extirpation,

16:40

but we need to be thinking forward

16:42

to restoration of course. So how do

16:44

we make a landscape that will work

16:46

for these caribou so that these are

16:48

truly interim actions and not, that doesn't

16:50

form the backbone of what keeps caribou

16:52

around forever. So what's

16:54

the next step for you now that you

16:56

have this information? I

16:58

mean, I think that the work here

17:01

can inform, you know, what are the

17:03

effective strategies to keep caribou around in

17:05

the interim? Like if folks are going

17:08

to be applying these interventions, then we

17:10

should use the ones that are working.

17:13

And for our research program

17:15

is certainly shifting rapidly towards

17:18

this restoration focus. So trying to

17:20

think about what does a landscape

17:22

that works for caribou look like

17:25

and how do we create it

17:27

as fast as possible, as

17:29

efficiently as possible and what are the strategies

17:31

that we haven't thought of that can help

17:33

us do that. Dr.

17:36

Lam, thank you very much for your time. Thank

17:39

you. Dr. Clayton Lam is a

17:41

wildlife scientist with Biodiversity Pathways and

17:43

the University of British Columbia, Okanagan.

17:56

The Chinook salmon is the biggest salmon living

17:58

in the Pacific North. Northwest today, it can

18:01

grow up to be a meter and a half

18:03

long and weigh over 100 pounds. But

18:07

once it had a relative that dwarfed it,

18:10

the now extinct Oncorhynchus rasterosus

18:12

was the largest salmon known

18:14

to science. It

18:16

was almost twice the length of the Pacific

18:18

salmon alive today, a full

18:20

three meters. And

18:23

if that wasn't impressive enough, it

18:25

also sported two oversized front teeth

18:28

that originally earned it the nickname

18:30

of the saber-toothed salmon. But

18:33

a new study by paleontologist Karen

18:35

Clason suggests that this name needs

18:38

a rethink, because those

18:40

teeth weren't fangs at all. Instead,

18:42

they stuck out of the side of

18:44

the salmon's head like tusks. Dr.

18:47

Clason is a paleo-ichthyologist and

18:49

professor of anatomy at the

18:51

Philadelphia College of Osteopathic Medicine.

18:54

Dr. Clason, welcome to Corks and Corks. Thank

18:57

you so much for having me. I'm really glad to talk

18:59

about this. When did we first

19:01

learn about these giant salmon? The

19:04

first giant salmon were found probably

19:06

in the 1960s, and then they

19:08

were ultimately published in the early 1970s. What

19:11

did they look like? So what

19:14

we can tell from most of

19:16

their bones is that they look like really

19:18

enormous versions of the salmon that we're aware

19:20

of now. And they

19:22

had this very unique bone

19:24

at the front of their mouths that would

19:26

have had this very large bulbous shape to

19:28

them and these enormous teeth

19:31

on them. And based on

19:33

what we think that most of the animals

19:35

would have been related to, we

19:37

assumed that they faced down like sabers.

19:39

So that was the original construction, to

19:41

have this very large head with big

19:43

fangs that faced into the mouth. When

19:46

did these salmon live? So

19:48

we have evidence that they would have

19:51

been around about five million years ago

19:53

at this point in time, probably transitioning

19:55

between the Miocene and the Pliocene. And

19:57

where were the fossils found? fossils

20:00

that we found around the time of 2011 till

20:02

2014, those were found in the same locality. It's

20:08

known as the Gateway locality in Oregon.

20:11

Oh, so they were Pacific

20:14

salmon then? Yes, definitely. They are

20:16

absolutely part of this entire group known

20:18

as the Pacific salmon. And you gave

20:21

the full scientific name earlier, which is

20:23

Oncorhynchus rastrosis. And Oncorhynchus is the genus

20:25

name for all of the living and

20:28

modern Pacific salmon as well. Well,

20:30

what made you reconsider these teeth that

20:33

were originally thought to look like fangs?

20:35

Well, the fact was that they found

20:38

remarkable specimens that had all of these

20:40

bones in place. So everything was in

20:42

situ. Everything was preserved in three dimension.

20:45

We had two fish very

20:47

closely situated together as if they

20:50

were in a breeding situation. And

20:52

they both had these enormous bones

20:54

plus their tusks and they were

20:56

all facing outwards. What do

20:59

you mean facing outwards? Tell me about that. So

21:01

as we thought with the saber tooth salmon

21:03

configuration, they would have faced down like we

21:05

have with all the modern salmon today. They

21:07

would have been able to grab at their

21:09

food and sliced it or grabbed and held

21:11

on really tight. It turns

21:13

out that these are filter feeding

21:16

salmon. And so they wouldn't

21:18

have used their teeth for that anyways. And

21:20

so now these teeth that are facing outwards.

21:22

They actually look more like a warthog. Some

21:25

people describe them almost looking like a mustache.

21:27

They have this completely unique configuration that looks

21:29

like they could have been spikes and used

21:31

for tools that if they

21:33

slash their head from side to

21:36

side, they would have created a

21:38

very, very unique aspect to these fish. So

21:40

what part of their face today stick out

21:42

of? So right at the tip of

21:44

their rostrum it's called. So right at the

21:46

front where we would expect the modern

21:49

salmon to have this major change happen during

21:51

metamorphosis. So if you've ever taken a look

21:54

at pictures of when they're breeding, they're this

21:56

bright red color and they have this kind

21:58

of greenish head. All of

22:00

the males have a very, very long russum.

22:02

Their nose almost looks like gonzo from the

22:04

Muppets. This is the

22:06

same bone that is changing in the

22:09

fish that we're describing. And

22:11

what's also interesting is though that males and females

22:13

are doing it in these fossils, which is unlike

22:15

what the modern do now. Boy.

22:19

And were they curved? Did they curve back

22:21

or curve forward or stick straight out? They

22:23

kind of blew up like balloons right at

22:26

the front, and then they just stuck

22:28

straight out towards the side. So instead of

22:30

creating this long hook in the front,

22:32

they actually more a tiny little

22:34

hammerhead almost if you will. Wow.

22:37

And you say both the males and the females had

22:39

this. They did. They

22:41

did. So unlike all of

22:44

the salmon that are around today, we

22:46

only see the changes occurring in a

22:48

few of the bones. And

22:50

so we still see the changes that are

22:52

occurring due to metamorphosis in

22:54

the males, but not on this particular

22:57

bone, not this pre-maxilla with these teeth.

22:59

So this is occurring in

23:01

both the male and the female on

23:03

this particular fossil, which is definitely unique.

23:06

Well, you said that these salmon

23:08

were filter feeders, sort of

23:10

like baleen whales. So they plankton and stuff like

23:12

that. They didn't eat other fish. So

23:15

why would they need these large teeth sticking up

23:17

the side of their head? That's

23:19

a great question. So the ideas

23:22

that we've been coming up with have a lot

23:24

to do with strategy for probably defense,

23:26

maybe a little bit of offense. And

23:29

these were really large. Perhaps they could have

23:31

been a very tasty meal for some type of predator. And

23:34

the fact that they were so large, they had

23:36

these very strong muscles that would have helped to

23:38

move their entire body while swimming. These

23:41

would also be able to move their head. And

23:43

so they could create a lot of force to

23:45

ward off some type of predator. They

23:47

could have created a lot of force to

23:49

keep other competition out of the way. It

23:51

makes me think a little bit of when you

23:53

think of the street races and the movie Grease

23:56

and their spikes coming out of their

23:58

tires or something to just keep them away from you. Perhaps

24:00

by the time that they got up

24:03

to the area where they were ready

24:05

to breed, they would have used them

24:07

for tools to actually build the nests

24:09

where the eggs on the sperm would

24:12

have been deposited. Once those

24:14

nests are in place and the fry exists,

24:16

they could have potentially protected that

24:19

nest from other sorts of predators as

24:21

well. Now, how can

24:23

you tell that this wasn't a one-off, that

24:26

not all of these giant salmon had these spiked

24:28

teeth? Well, the fact that we

24:31

didn't have only one specimen with this configuration

24:33

was a good tip-off. And

24:35

then we were actually using medical

24:37

imaging. We used CT scanning at

24:39

an industrial strength to look inside

24:42

the rock and start to remove

24:44

the sediment and the matrix that

24:46

was surrounding and protecting the really delicate parts

24:48

of the bones that we don't tend to

24:50

get to see otherwise

24:52

when the fossils are preserved.

24:55

So by using this technology to

24:58

appear inside the entire skull, we

25:00

were able to find the small processes that

25:02

fit together like puzzle pieces that

25:04

said that this is the actual configuration that

25:06

it should have been. What

25:08

went through your mind when you realized that these

25:10

salmon had this strange formation sticking out the sides

25:12

of their heads? I just thought it

25:14

was really fascinating and thought to myself, again, why

25:17

would you be doing this? And

25:19

why don't we see it in a lot of

25:21

other animals now? It's not a strategy that a

25:23

lot of animals are using at all. And

25:26

so it was pretty unique. Well, why

25:28

do you think modern day salmon don't have these

25:30

teeth? So if you think about

25:32

it from an evolutionary perspective, these are

25:34

not the ancestors to the modern salmon.

25:36

They're probably more derived

25:39

or as derived as some of the ones

25:41

that are around now. So it wouldn't have

25:43

been something that came first and then left

25:45

the modern ones around. These actually existed and

25:47

co-existed at the same time as some of

25:49

the species that are around today like the

25:51

sockeye. And

25:53

I think it was a very interesting experiment. And

25:56

so not a lot of the other ones though

25:58

would have tried it. seems, at least

26:00

based on what we can see in the fossil record. So

26:03

for any time travelers out there, if you go back

26:05

a million years or so, don't go swimming in the

26:08

ocean. Yeah, I know. Well,

26:11

there are some pretty large animals that are

26:13

in the ocean nowadays, but they don't school

26:15

quite as much as what we would think

26:18

about for those salmon as well.

26:20

So could you imagine seeing so many of

26:22

them all together at once coming and charging

26:24

at you? I don't know. That

26:27

would have been pretty crazy. Patrick Gleason, thank you so much for your time.

26:29

Thank you. Dr. Karen Gleason

26:31

is a paleo ichthyologist and an

26:33

anatomist at the Philadelphia College of

26:36

Osteopathic Medicine. I'm Jordan

26:38

Heathralling's host of The Big Story. For

26:41

six years now, we've been telling one

26:43

story a day, every one of them,

26:45

about something that matters to Canadians. This

26:47

spring, though, we're going deeper. The

26:50

Big Story presents Paydirt,

26:52

the inside story of Ontario's

26:54

Greenbelt scandal, from political games

26:57

to stag and doe parties,

26:59

endangered species, RCMP investigations and

27:01

Las Vegas massages. You

27:04

will hear the full story. The Big

27:06

Story presents Paydirt, new episodes

27:08

every Monday, and you can get

27:10

them all by following The Big

27:12

Story wherever you get your podcasts.

27:16

I'm Bob McDonald, and you're listening to Quarks

27:18

and Quarks on CBC Radio One. Coming

27:20

up later in the program. Could

27:22

the universe be full of tiny black holes

27:25

that occasionally blast through our planet? So it's

27:27

like a bullet through cotton candy. These things

27:29

enter one side of the planet, they're out

27:31

the other, and then they're off into space,

27:33

never to come back again. Fourteen

27:37

years ago this month, the

27:39

Deepwater Horizon oil well disaster

27:41

began, ultimately releasing

27:43

an estimated 800 million liters of

27:46

oil and gas into the Gulf

27:48

of Mexico. It was

27:50

the largest accidental marine oil spill

27:52

in history. At

27:55

the time, scientists flocked to the

27:57

scene to understand how this unprecedented

27:59

pollution Not just the

28:01

oil, but the chemical dispersants released to

28:03

break up the spill would affect

28:05

the rich ecosystem in those waters. Much

28:09

of the early research focus was

28:11

on the economically important species in

28:14

the area, like tuna, swordfish, shrimp

28:16

and oysters, and

28:18

these species fortunately recovered

28:21

quickly. That seemed like good news.

28:24

Canadian biologist Pro Santa Chakrabarti was also

28:26

on the scene at the time, but

28:29

he was focused on the rarer creatures that

28:31

live only in the deepest parts of the

28:33

Gulf, closest to where the

28:36

chaos was happening. And for

28:38

these animals, the picture is less rosy.

28:41

In his latest study, Dr. Chakrabarti and

28:43

his colleagues report that out of the

28:46

78 endemic species, 29 of

28:48

them haven't been spotted in the years since the

28:51

spill. Dr. Chakrabarti

28:53

is a professor and curator

28:55

of fishes at Louisiana State

28:57

University's Museum of Natural Science.

28:59

Hello and welcome to our program. Thanks for having me.

29:02

Now we've heard for a while how the

29:05

fish populations in the Gulf seem to be

29:07

holding steady after the spill, but

29:09

now you're saying that's not the whole story? Yeah,

29:12

unfortunately it's not. You know, we

29:14

typically focus on the food fish

29:16

that we eat, right? The fish

29:18

that are commercially important. But

29:21

those are only a handful of species while

29:23

there's actually 1,500 or

29:25

more species in the Gulf of Mexico of fishes.

29:28

And those are the ones I'm also

29:30

interested in that are often overlooked, and

29:32

that's the focus of these papers. Well,

29:35

why did you want to focus on the animals in the deep

29:37

ocean? Well, the oil spill happened in

29:40

the deep sea. So

29:42

that's the part of the world, not

29:44

just the Gulf of Mexico, but of

29:47

the world that we know the least

29:49

about, this deep sea, cold, perpetually dark

29:51

ecosystem that houses some amazing species that

29:53

are bioluminescent, that are doing all kinds

29:56

of things that we know very little

29:58

about, and, you know, they're endangered,

30:01

then somebody has to speak for them.

30:03

And that's our role as scientists. Well,

30:06

now 14 years after the disaster, what

30:08

do we know about the long-term effects

30:11

of the oil spill? Not

30:13

as much as we would suspect that we would

30:15

know by now. Still, 14 years

30:18

later, another spill were to happen

30:20

tomorrow. I'm afraid that we just

30:22

don't know the impacts of how

30:25

a deep sea environment would be

30:27

impacted and affected any better

30:29

than we were 14 years ago. And

30:32

that's problematic. And it's in part due

30:34

to the difficulty in studying the deep sea.

30:37

There have been efforts to make

30:40

new collections, to make new

30:42

environmental impact assessments. But

30:44

it's still a drop in the bucket compared

30:46

to how much we could know. Well,

30:49

you mean nobody's been down to actually look at

30:51

what's going on down there? Not

30:54

in a way that people would expect. So

30:56

it's not like we can easily get to

30:58

1,000 meters. Very

31:00

few submersibles exist that can

31:03

get to the bottom of the ocean still.

31:05

And long-term studies

31:08

are just difficult to do in these

31:10

perpetually dark environments. And so figuring

31:14

out populations of deep sea fishes

31:16

is almost impossible. Well,

31:18

tell me about how you've been looking at

31:21

the species that seem to be disappearing. Yeah,

31:24

for me, as a museum curator,

31:26

our collections are this library

31:29

of the Earth's biodiversity. And

31:32

these collections have specimens or

31:34

vouchers, as we call them,

31:36

of creatures from around the

31:39

world. And so I thought it'd be

31:41

useful to use this library. And

31:44

we all share our data. So

31:46

we can look online and see

31:48

where specimens from around where the

31:50

spill happened, where

31:52

were they collected, when were they collected,

31:55

and can we make a sort of

31:57

guesstimate or estimates of how

31:59

these populations are doing. So

32:02

I want to know what species

32:04

have we not seen since the time of

32:06

the spill or from before the spill that

32:08

we should know more about. And those

32:10

are the 29 species that you mentioned that

32:12

are still quote, missing, things

32:15

that we haven't seen from the time of the

32:17

spill or before. So how many

32:19

animals usually get added to a museum collection?

32:22

That's an interesting point. And so it

32:24

sort of depends if there's survey work

32:26

being done. So in my

32:28

own collections here, we have

32:30

about 300,000 fish from 60 or so different countries.

32:35

And 300,000 fish sounds like a lot. But

32:37

5 million fish are caught every minute

32:39

by the fishing industry. So

32:42

often what's being caught in the

32:44

Gulf and other parts of North

32:47

America, what's not the target

32:49

fish. So if they're targeting menhaden, all

32:51

that other fish gets thrown overboard, the

32:53

bycatch. And so that's

32:56

a larger portion of some

32:59

of the species that might be so-called missing

33:01

that we might not have data for. And

33:04

so they only become data when they're in a

33:06

museum collection. And that's what we're here for. Are

33:09

there any species that only exist in

33:11

the Gulf of Mexico? Yeah, in fact, those

33:14

are the species that we were targeting. So

33:16

there's 1,500 or so species

33:18

in the Gulf of Mexico. But many of them are

33:20

found in this very

33:22

wide range. I was

33:24

interested in those that are only found in

33:26

the Gulf of Mexico, so not even in

33:29

the Caribbean or on the eastern coast of

33:31

the US. So

33:33

those species, there's only 78 of those

33:35

species. And

33:38

so those are the ones that we focused on as

33:40

sort of a proxy for what's going on

33:42

in the entirety of the Gulf. Well,

33:45

tell me about some of these animals.

33:47

What are they like? Yeah, perhaps the

33:49

most well-known of these will be the

33:51

pocket shark. So that species was actually

33:53

described around the time of the oil

33:55

spill. And it's a

33:57

shark that's not even a foot long, big

34:00

old head. It's actually very cute as far

34:02

as sharks go. It's got

34:04

dark skin, it's bioluminescent, and

34:07

so it produces light. And there's

34:10

only been one specimen ever found, ever.

34:13

There's a fringe lantern shark,

34:15

which was only seen right before this

34:17

bill in 2009. There's an eel

34:21

pout and other sharks and rays and

34:23

hag fish, things that people don't eat

34:25

and most people don't think about, but

34:27

I do and other scientists

34:29

do. And some of those

34:31

that I mentioned haven't been seen since

34:33

the 60s, from well before the spill.

34:36

But even with targeted efforts, we would expect

34:39

to see one or two more specimens, but

34:41

they are only known from the Gulf and

34:43

we haven't seen them since. Now,

34:46

is it possible that the reason these

34:48

species haven't been seen is that, well,

34:50

they've just evaded capture all these years?

34:52

Oh, certainly, yeah. So some of these

34:54

species have, again, you know, haven't been

34:56

seen since the 60s. And

34:59

they're deep sea animals that are very hard

35:01

to get. The Gulf's a very big place

35:04

and so you just have

35:06

to get lucky sometimes. But with

35:08

more effort and especially around the region

35:11

of the spill, I think we can

35:13

learn more and we should learn more

35:15

about what exists. Now

35:17

you were on site at the oil spill 14

35:19

years ago. Did you think you'd still be calling

35:21

attention to the deep sea animals all these years

35:24

later? When I came

35:26

to Louisiana, and I'm a Canadian who

35:28

lived in New York for a long

35:30

time before I moved here in 2008,

35:33

I didn't really feel like a Louisiana until

35:35

the oil spill happened. It made me really

35:37

feel a connection to this place. And all

35:39

of a sudden, I just fell in love

35:41

with the Gulf, especially when it was endangered.

35:43

This 12 weeks of the spill made

35:46

me really feel like Louisiana was home.

35:48

And it's still very much home 15

35:51

years later since I've

35:53

been here. And I couldn't

35:56

imagine then how little we still

35:58

know. the remnants

36:00

of the oil at the surface was gone, it

36:02

was out of sight and out of mind. And

36:05

even though there may be smaller spills,

36:07

the impact of that spill, I

36:10

wish we knew more. And I'm surprised we still know

36:12

so little 15 years later. So

36:15

the Gulf is this wonderful place shared

36:17

with several countries that I

36:20

think deserves more attention. Dr.

36:23

Chakrabarti, thank you so much for your time. Thank

36:26

you for having me, and thanks for calling attention

36:28

to the spill. Dr. Prasanta

36:30

Chakrabarti is a Curator of

36:32

Fishes at Louisiana State University's

36:34

Museum of Natural Science. Let

36:51

me take you back to the Big Bang. The

36:54

universe explodes into existence

36:57

as an infinitely dense, infinitely

36:59

hot point, and immediately

37:01

starts to expand at a tremendous

37:03

rate. Almost

37:08

instantaneously matter evolves out of

37:10

pure energy, and the

37:13

tiny proto-universe is filled with

37:15

super-hot stuff. Then,

37:18

perhaps, something very strange

37:20

happens. So it's possible

37:23

that just white noise, little

37:25

fluctuations in the density of this huge

37:27

bath of matter in the early universe,

37:29

could have produced huge numbers of black

37:31

holes that could have had really any

37:33

range of masses. That's

37:35

physicist Matt Kaplan, and what he's

37:37

talking about is the theory of

37:39

primordial black holes. These

37:42

are black holes that have been around for 13.7 billion years

37:44

since the birth of our

37:47

universe. And if

37:49

researchers' suspicions are correct, they

37:51

could come in a range of sizes, from

37:54

the unimaginably tiny to the

37:57

supermassive, and the universe

37:59

might be full. of them. Invisible.

38:01

Largely undetectable. Some

38:04

of the smallest of these

38:07

primordial black holes might also

38:09

be a promising candidate to

38:11

explain another mystery. The coincidentally

38:13

invisible and so far undetectable

38:15

dark matter that astronomers say

38:18

makes up more than four-fifths of the mass

38:20

of the universe. Dr.

38:22

Kaplan. It's just a fact that most

38:24

of the matter in the universe doesn't

38:26

light up. It doesn't seem to interact

38:28

with light and it doesn't seem to

38:30

have electric charge. So this

38:33

puts real restrictions on what it could

38:35

be. It might be some new undiscovered

38:37

particle. But when I think of matter

38:39

that doesn't light up, black holes

38:41

really fit the bill perfectly, right? I mean, I'm

38:43

not crazy for thinking that. Well,

38:45

history will be the judge. But

38:47

if he's right that these primordial black

38:50

holes form shortly after the Big Bang,

38:52

the next natural question is, can

38:55

we find the ones that could be the solution

38:57

to the dark matter mystery? Well,

39:00

maybe. And maybe right

39:02

in our stellar neighborhood. Dr.

39:04

Kaplan is a professor of physics

39:07

at Illinois State University in Normal,

39:09

Illinois. Hello and welcome back to Quirks

39:11

and Quarks. Hey Bob, good to be back.

39:13

First of all, tell me what a primordial

39:15

black hole is. So

39:18

a primordial black hole is a

39:20

black hole. Let's start with that. A black

39:22

hole is just this overdense region of space

39:24

time that's collapsed on itself to produce a

39:26

singularity. The question then is what

39:28

makes a black hole primordial and that's when

39:30

it formed. It takes very dense matter to

39:32

make black holes. So the most obvious way

39:34

to do this is in a supernova and

39:36

that makes these order solar

39:38

mass black holes. But the early

39:41

universe was incredibly dense. So it's

39:43

possible that just white

39:45

noise, little fluctuations in the density of

39:47

this huge bath of matter in the

39:49

early universe could have produced huge numbers

39:51

of black holes that could have had

39:53

really any range of masses. Why

39:55

do you think primordial black holes may be

39:57

the answer to the dark matter problem? I

40:00

like primordial black holes as a

40:03

dark matter solution because it

40:05

doesn't require new physics

40:07

beyond what we already know. If

40:09

dark matter is a new undiscovered

40:11

particle, that would be really cool,

40:13

that would be really exciting but

40:15

that's also this massive theoretical garden

40:18

of how many millions of

40:20

different possible particles that we

40:22

could theoretically think up. And

40:25

that's a step away from

40:27

known physics. Black holes are not unknown physics,

40:29

they are very well known. We've seen plenty

40:31

of them, we've seen the merging LIGO black

40:34

holes. So I don't think it would be

40:36

too much of a stretch to think that

40:38

some large number could have been produced in

40:40

the early universe. It seems like it has

40:42

the fewest assumptions of any dark matter explanation

40:45

I've ever seen. Okay, so primordial black holes

40:47

are the answer to dark matter. There's a

40:49

lot of dark matter out there so what

40:51

does that mean for how common these little

40:53

black holes would be? It

40:56

depends on their exact mass, right? So

40:59

the less massive these black holes would

41:01

be, the more abundant they would be

41:03

by number. And so they could

41:05

be whizzing through the solar system even if

41:07

they're low enough mass. But if

41:10

dark matter is made of black holes and they're

41:12

passing through our solar system, wouldn't we notice that?

41:14

Because black holes do have a tendency, as you

41:16

say, to eat things and stuff

41:18

that falls into them lights up and all that.

41:21

Yes, they would be very easy

41:23

to miss. The amount of dark matter in the

41:25

solar system is comparable to a molten. So if

41:28

we said, well, what if that was all a

41:30

black hole? So what if there was roughly one

41:32

black hole, the mass of a mountain, passing through

41:34

the solar system at any given time? That

41:36

black hole would also be about the size of an atom.

41:39

So it would be very easy to miss. You're probably not

41:41

going to find it with a telescope. But

41:43

you're onto it, which is that

41:45

occasionally things will hit planets,

41:48

stars, moons. And when

41:50

that happens, then something exciting and observable

41:52

could happen. Wait a minute. A

41:54

black hole the size of an atom? Oh,

41:56

yeah. Yeah. Straightforward homework problem.

42:00

So it's the sort of asteroid mass black

42:02

holes that could potentially explain the dark matter

42:05

So what then would happen if

42:08

one of these atom-sized black holes was to hit

42:10

the earth? So people

42:12

have thought about this there are actual real

42:14

peer-reviewed Publications about what would happen if

42:16

one of these itty-bitty teeny tiny black holes hit

42:18

the earth if you can believe it or not

42:22

So a black hole of that

42:24

mass would be falling in at a very

42:26

high speed. It's coming from the galaxy So

42:29

it's going fast. It's falling towards the earth

42:31

and accelerated by Earth's gravity So it's going

42:33

to be fast So it's going significantly faster

42:35

than escape velocity when it enters the atmosphere

42:37

and it's so small It can

42:39

barely eat any mass while it's passing through

42:41

the planet So it's like a bullet through

42:44

cotton candy these things enter one side of

42:46

the planet They're out the other and then

42:48

they're off into space never to come back

42:50

again And it all happens in a few

42:52

seconds Wow So they're above the

42:54

atmosphere and they're invisible and then as soon as

42:56

you put matter around them that they can start

42:58

To pull in they're going to start

43:00

to get very hot and bright because matter falling

43:03

into a black hole is going very fast It

43:05

gets heated by friction colliding with other matter that's

43:07

falling in and what you get

43:09

are these really bright accretion discs These

43:11

are the pictures that you usually see

43:13

those orange bands around black holes. Those

43:15

are these accretion discs So you

43:17

have a black hole that's now entering the atmosphere

43:19

and it is lighting up like a fire as it

43:22

streaks through the sky Punches through the planet punches all

43:24

the way through to the other side and leaves like

43:26

a shooting star coming up from the ground Okay,

43:30

so if one passed through my house what I noticed

43:33

Yeah, you your house would probably be

43:35

on fire and It

43:38

depends on the mass of the black hole

43:40

because the masses have this huge range of

43:42

masses The smallest ones could potentially leave your

43:44

house intact and the biggest ones would probably

43:46

destroy your house and the neighbors Now

43:49

do we have any evidence that little black

43:51

holes have gone through the earth and he

43:53

scars any any holes through the planet? So

43:57

to the best of our knowledge we haven't found

43:59

any of these that doesn't mean they don't exist.

44:01

And that's because the Earth has surface

44:03

processes. It has rain, it has wind,

44:06

it has erosion, it has seasons. All

44:08

of these things tend to erase surface

44:11

impacts in craters. Only the

44:13

largest, biggest, beefiest craters in

44:15

deserts stick around for a

44:17

really long time. So

44:19

if you did wanna look for evidence

44:21

of primordial black holes hitting the Earth,

44:24

you should probably start with the moon because the

44:26

moon doesn't have those things that would

44:28

erase the evidence of those impacts. Okay,

44:32

so do we have any evidence on the

44:34

moon? I know it's covered in a lot

44:36

of craters. It's been hit a lot by

44:38

real asteroids, like actual asteroids. Any signs that

44:40

it's been hit by black holes? Indeed

44:43

it has. And so this is

44:45

a search that's ongoing. We have

44:47

done our first attempt and

44:50

the sizes of these black holes mean that

44:52

their craters are only a couple meters in

44:54

size. So think about the size of a

44:56

car. You could comfortably fill up one

44:59

of these craters just by standing in

45:01

it. And the highest resolution

45:03

surface scans that we have of the moon

45:06

are about a football field per pixel,

45:08

so like order 65 meters. And

45:11

as a result, the craters are too small to

45:14

even show up as one pixel if they exist.

45:16

So we've done a search for them as

45:18

a proof of concepts computationally through all of

45:21

these images. And we can't push

45:23

low enough to find them, but that doesn't mean they're

45:25

not there. What we hope is

45:27

that some future generation of satellite will

45:29

take surface images

45:31

that are 10 times higher in

45:34

resolution. And with that, we could

45:36

reasonably test this hypothesis. Well,

45:38

how could you tell the difference between a crater made

45:40

by a black hole and one made by an asteroid?

45:43

That is another fantastic question,

45:45

Bob. So a regular crater

45:47

is rock hitting rock. So that's like

45:50

a point explosion. That's like piling up

45:52

a bunch of TNT on the surface

45:54

and then detonating it. That's gonna make

45:56

those nice big round basin craters with

45:58

the ejecta blankets around it, sloping

46:00

anthill that sort of comes away from the

46:02

crater. A black hole doesn't do

46:05

that precisely because it goes

46:07

straight through the moon. The

46:09

black hole is a creating matter

46:11

creating this high

46:14

density, high pressure, high temperature volume

46:16

around it and it does this

46:18

as a big stripe. So

46:20

instead of having a point explosion like

46:22

the TNT on the surface or the

46:24

asteroid hitting it, you have a line

46:26

explosion. You could think it's the difference

46:28

between having all of your TNT and

46:30

a big pile on the surface versus

46:32

drilling a borehole and then filling that

46:34

with TNT and then detonating it. The

46:36

cratering dynamics and how it spreads matter

46:38

around the crater are going to be

46:40

different resulting in a different crater shape.

46:44

So would you have a hole right through the moon

46:46

and an exit crater on the other

46:48

side? You do get an exit

46:50

crater on the other side. So this is fortunate

46:52

for us. If a later asteroid comes and overwrites

46:54

one of them, you still have the other one

46:56

on the far side. So you don't have to

46:59

worry too much about that. The

47:01

hole through the moon, fortunately the moon's not

47:03

Swiss cheese. If you are deep

47:05

enough in the moon, the pressure is high

47:07

enough that the sort of sand and rock

47:09

will flow back and fill it in. So

47:11

you shouldn't think of it as like you're

47:14

gonna look through and see out the other

47:16

side. This is going to, on the surface,

47:18

look like a crater. It's just going to

47:20

have different dimensions than asteroid or impact made

47:22

craters. Okay, so we haven't seen

47:24

any black hole craters on the moon yet,

47:27

but possibly with instruments and better

47:29

resolution we might spot them. You

47:32

got it. Dr. Kaplan, thank

47:34

you so much for your time. Yep, so

47:36

good to be here. Thanks Bob. That

47:38

was Dr. Matt Kaplan, a professor of

47:40

physics from Illinois State University. Now

47:43

what's exciting is that if these

47:45

tiny primordial black holes are the

47:47

answers of the dark matter mystery,

47:49

we might already

47:51

have the observations we need to find

47:53

them. Theoretical physicists

47:55

from Belgium are proposing we

47:57

could find indirect evidence of

48:00

them from outside of our Milky

48:02

Way galaxy. All we

48:04

have to do is look for the

48:06

shadow of the shattered remains of stars

48:08

they've destroyed. Nicolas

48:10

Esser is the lead author of

48:12

the study and PhD candidate of

48:15

theoretical physics at the French pre-University

48:17

of Brussels. We caught up

48:19

with him in Montreal. Hello Mr.

48:21

Esser, welcome to Quarks and Quarks. Hello

48:23

Bob, thanks for having me. So where

48:25

do you think we might be able to

48:27

detect primordial black holes? Well

48:30

one possibility to study ultra-fine

48:32

dwarf galaxies. These galaxies

48:34

are small galaxies which are satellites of

48:36

our own galaxy, the Milky Way. Small

48:39

galaxies, now why these dwarf galaxies and

48:42

not our own Milky Way? So

48:46

in these galaxies we have seen for

48:48

observations of the motion of the stars

48:51

that there must be more dark matter

48:53

in there and hence potentially more black

48:56

holes. So if they

48:58

are the mass of an asteroid they would actually be

49:00

the size of an atom and

49:02

we wouldn't be able to see them which

49:04

is why we need some indirect

49:06

way of proving them. Okay,

49:09

since we can't see black holes what

49:12

are we going to see with the stars in their relationship

49:14

to the black holes? So one

49:17

possibility is that if primordial

49:20

black holes exist and are roughly of

49:22

the mass of an asteroid what

49:24

could happen is that when stars

49:26

form it actually starts from a

49:29

huge cloud of gas, a cloud which is

49:31

like tens of times the

49:33

size of our own solar system

49:36

and this cloud of gas when contracting

49:39

will carry with it the primordial

49:41

black holes that are moving around in

49:43

this cloud and these black holes would

49:46

be carried with the gas towards

49:48

the final product of this contraction which

49:50

is the star and

49:52

since this scenario works

49:54

better for heavier stars what

49:57

could happen is that this black hole would end up

49:59

well completely. stuck in the star

50:01

and would eat it. Oh

50:03

I see, so they would get caught up in

50:06

the big clouds of what just slow down by

50:08

friction because they're so small and end up inside

50:10

the star. So what happens from

50:12

that point? What has star with a black hole

50:14

in its center? What

50:17

happens from that point is that well we

50:19

know that black holes they basically

50:22

attract everything that's around them and once

50:25

you've entered a black hole you cannot get

50:27

out and what would happen is that

50:29

the matter in the star would slowly

50:31

get attracted inside the black hole

50:33

would be basically strongly eaten

50:36

with the technical term is accreted and

50:39

the black hole would slowly eat the particles of

50:41

the star and in a few million years what

50:43

could happen is that the stars would be completely

50:45

destroyed and there would be nothing

50:47

less apart from a remnant black hole which

50:50

would be roughly the mass of this initial

50:52

star. Holy smoke, talk

50:55

about indigestion, a star being

50:58

eaten from the inside out. Yeah that's

51:00

kind of the idea. Now you mentioned

51:02

that this would only happen to big

51:04

stars, why is that? Well

51:06

the reason is that if you have

51:08

a bigger star this means you

51:10

have a stronger gravitational attraction and

51:13

also you start with a bigger cloud

51:16

which means that you just have a

51:18

higher probability of capturing a black hole

51:20

and of getting an indigestion when

51:22

you have a bigger star. Okay

51:25

so then where will

51:27

the data come from when you're looking at

51:29

these dwarf galaxies that will tell you that

51:31

these primordial black holes are there that they've

51:33

eaten these stars? So

51:35

the observation we

51:37

could use is called the mass

51:40

function of the stars and this

51:42

basically is just the information of

51:44

how many stars you have for

51:46

a given star mass

51:49

right so this gives you the function of

51:52

the number of stars that functions their masses and

51:54

we can observe we can

51:57

measure this using our last telescopes such

51:59

as the the Hubble telescope, the James

52:01

Webb telescope, as well as the Euclid

52:03

telescope. These telescopes could allow us to

52:05

measure these mass functions, and if we

52:08

see that heavy stars

52:10

are missing, then this could

52:12

give us a hint that there is

52:14

primarily black holes in the 12th galaxy.

52:17

Oh, I see. So it's what you

52:19

don't see in these galaxies that tells you the

52:21

black holes are there if the big stars are

52:23

missing. Exactly. How

52:26

far along in this process are

52:28

you to count how

52:30

many big stars are missing out

52:32

of these galaxies? So actually,

52:36

there already exist measurements of

52:38

star counting in these galaxies.

52:40

These measurements exist. What

52:42

we are trying to do now is to

52:44

obtain these results, which are now in the

52:46

end of other astrophysicists, and try

52:49

to analyze the data with this idea

52:51

that high mass stars should be

52:53

missing. OK,

52:55

so if you do detect that

52:58

these big stars are missing

53:00

from these dwarf galaxies, and

53:03

that shows that there's probably black

53:05

holes there, what would

53:07

that say to you about the idea

53:10

that primordial black holes are going to

53:12

solve our dark matter mystery? I

53:15

wouldn't say it would be like a pure

53:17

confirmation that there is asteroid mass primordial

53:19

black hole in these galaxies, but it

53:21

would be a great hint towards this

53:24

idea. But of course, there could be

53:26

some other astrophysical explanations for missing high

53:28

mass stars in these galaxies. But it

53:30

would be a hint, and it would

53:32

motivate further study. How

53:35

much closer would your observations bring us

53:37

to the idea that these primordial black

53:39

holes even exist? It

53:42

cannot be approved, because it's still indirect,

53:45

so there can be other

53:47

explanations. But if

53:49

you combine different observations, among

53:52

which would be this observation of missing

53:54

high mass stars, then at some point

53:56

you would be convinced that, OK, that

53:59

it must be. these black holes

54:01

because we have three, four, maybe five

54:03

different observations. They all correlate. They all

54:05

say, okay, there should be

54:07

black holes. So it would

54:09

be a step among others to prove the

54:11

existence of these black holes. Mr.

54:14

Esser, thank you so much for your time. Well,

54:16

thanks for having me again. That was

54:19

Nicolas Esser, a PhD candidate at

54:21

the French Free University of Brussels.

54:25

And that's it for Quirks and Quarks this week. If

54:28

you'd like to get in touch

54:30

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54:32

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54:34

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54:36

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54:41

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54:50

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54:59

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