Latest / Daniel and Kelly’s Extraordinary Universe / What can slime molds teach us about dark matter?

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What can slime molds teach us about dark matter? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Katie, how do you feel about mushrooms. I'm a
0:12
Speaker 1: big fan. They actually make a mean pizza fung Guy
0:15
Speaker 1: over here that reminds me of the best pizza I
0:18
Speaker 1: ever ate. It was covered in morals. I still think
0:21
Speaker 1: about that pizza, like twenty years later. Yeah, they actually
0:24
Speaker 1: have these really good fried mushrooms, these local ones, and
0:28
Speaker 1: it was absolutely amazing. But yeah, that is that is
0:31
Speaker 1: entry level stuff, Daniel. If you're a real mushroom fan,
0:36
Speaker 1: you would be into the weirder varieties. I'll bring on
0:40
Speaker 1: the challenge, you know, hand in the woods, oyster mushrooms.
0:43
Speaker 1: I'm into all of it. You young young, Well, what
0:45
Speaker 1: about manticor's tongue? Is that real? Did you just make
0:50
Speaker 1: that up? Wait until you see monkey's head? Well, put
0:55
Speaker 1: it on a pizza and I will take a bite. Hi.
1:13
Speaker 1: I'm Daniel. I'm a particle physicist and a professor at
1:16
Speaker 1: UC Irvine, and I will taste any mushroom that isn't
1:20
Speaker 1: labeled as toxic. I am Katie Golden, and I too
1:25
Speaker 1: will eat any mushroom as long as you eat it first.
1:28
Speaker 1: I am the host of the podcast Creature Feature, and
1:32
Speaker 1: I'm stepping in for Jorge or, as some theorize on
1:36
Speaker 1: the Internet, we are actually sort of like two states
1:39
Speaker 1: of the same person. Maybe if you eat the right
1:42
Speaker 1: mushroom returned into Jorge, is that how it works? I'll
1:44
Speaker 1: never tell the banana mushroom. Well, Welcome to the podcast
1:49
Speaker 1: Daniel and Jorge Explain the Universe, in which we take
1:52
Speaker 1: a big juicy bite out of the weirdest, strangest, slimiest
1:57
Speaker 1: mysteries in the universe. We think that the whole universe
2:00
Speaker 1: deserves to be understood, deserves to be explained, and deserves
2:04
Speaker 1: to be explored, at least mentally by these funny little
2:07
Speaker 1: apes living on this weird little rock in the corner
2:10
Speaker 1: of the galaxy. We think all of it should make sense,
2:12
Speaker 1: and we do our best to tackle the biggest, weirdest, slimiest,
2:16
Speaker 1: amazing questions about this bonkers and beautiful universe and explain
2:20
Speaker 1: all of it to you. My friend and co host
2:22
Speaker 1: Orgy can't make it today. As it as usual, we
2:24
Speaker 1: are very grateful to have Katie usual host of Creature
2:27
Speaker 1: feature podcast. Katie, thanks again for joining us. Yeah, absolutely,
2:30
Speaker 1: I am pumped to be on. I guess like the
2:34
Speaker 1: slimiest episode you guys have ever done. Did you eat
2:38
Speaker 1: some slimy mushrooms to prepare yourself to get yourself in
2:41
Speaker 1: the right mental frame. I just kind of licked the
2:43
Speaker 1: walls of a cave, a random cave, to get myself
2:46
Speaker 1: in the right mindset. I think everybody out there just
2:50
Speaker 1: had their stomach turnover that mental imagic key not into
2:56
Speaker 1: cave cave tasting. I see, Oh well, and I suggest
3:01
Speaker 1: that nobody out there google cave tasting because you have
3:03
Speaker 1: no idea what might pop up. But today on the podcast,
3:07
Speaker 1: we're gonna be taking advantage of Katie's knowledge of biology
3:09
Speaker 1: to try to bring together two very disparate topics, to
3:13
Speaker 1: try to unify our desire to understand the whole structure
3:17
Speaker 1: of the universe, its shape, its form, its history, together
3:20
Speaker 1: with the things that we see here down on Earth.
3:24
Speaker 1: You know, a lot of folks write to me and
3:25
Speaker 1: wonder about whether there are connections between the shape of
3:28
Speaker 1: the universe on the biggest scale, you know, this cosmic
3:31
Speaker 1: web with filaments and sheets of stars and the patterns
3:35
Speaker 1: that we see down here on Earth, or the organization
3:38
Speaker 1: of the atoms, as if maybe there's some deep structure
3:40
Speaker 1: to the universe, and it reveals itself on many levels. Yeah,
3:44
Speaker 1: I love that. I think that they're often seems to
3:47
Speaker 1: be this parallel between the facets of physics, like the
3:53
Speaker 1: kinds of behaviors that particles will exhibit and the behaviors
3:58
Speaker 1: that biological organisms will exhibit. So these patterns that we
4:03
Speaker 1: see for these you know, inorganic particles will pop up
4:09
Speaker 1: when you're looking at organic particle organic organisms, and I
4:13
Speaker 1: just find that so fascinating. It is fascinating because it
4:16
Speaker 1: hints at something really really deep. If you discover some
4:19
Speaker 1: basic mathematics about the way the particles organized themselves, and
4:22
Speaker 1: it also applies to the way sea lions build colonies
4:26
Speaker 1: and the way that galaxies organize themselves. That suggests that
4:29
Speaker 1: you've revealed something really really true about the universe, that
4:32
Speaker 1: there's an organizing principle of play that can unify them.
4:35
Speaker 1: You know. One of the first people to do this
4:37
Speaker 1: was Isaac Newton. His theory of gravity could describe not
4:40
Speaker 1: just the motion of apples falling from trees, but also
4:43
Speaker 1: the motions of bodies in the heaven. And so to
4:46
Speaker 1: have this moment where you feel like, oh, I've discovered
4:48
Speaker 1: something which is true not just about what's around me,
4:51
Speaker 1: but also about what's in the sky and maybe about everything.
4:55
Speaker 1: That must have been an incredible moment. Of course, we
4:57
Speaker 1: know now that he was wrong about everything, but you know,
5:01
Speaker 1: the idea that you could potentially discover these organizing principles
5:05
Speaker 1: that work across incredibly distant length scales, because galaxies are
5:09
Speaker 1: hundreds of thousands of light years across, and particles are
5:13
Speaker 1: tend the minus twenty meters across, and so to imagine
5:17
Speaker 1: that you could have rules that describe everything on those scales,
5:20
Speaker 1: it's very tempting, it's very tantalizing, and I think that's
5:23
Speaker 1: why people look for these connections, and that's why we're
5:25
Speaker 1: gonna talk about some of those today. Yeah, even Alan
5:28
Speaker 1: Turing would sometimes use his incredible genius level skills to
5:35
Speaker 1: make these connections between things like math and particles and biology.
5:40
Speaker 1: Like he explored the how animals can have things like
5:44
Speaker 1: stripes or spots, like these clusters of melanin, and he
5:50
Speaker 1: worked out this whole kind of model with like the
5:53
Speaker 1: move randomized movements of particles and sort of using that
5:58
Speaker 1: as a way to understand and how you could get
6:01
Speaker 1: a pattern like stripes through the like semi random movement
6:06
Speaker 1: of say like melanine cells. And it's really it's just
6:09
Speaker 1: so interesting how deep these things go, like these very
6:14
Speaker 1: broad mathematical or physics based principles. Yeah, it's like the
6:19
Speaker 1: universe is a grand experiment and it's revealing the underlying
6:22
Speaker 1: rules as it plays out, and if you pay attention,
6:25
Speaker 1: you can spot them here, and you can spot them there,
6:27
Speaker 1: and you can learn things about galaxies by looking at
6:30
Speaker 1: things under a log in the forest. The universe is
6:33
Speaker 1: the world's biggest escape roam. That's exactly. There are clues everywhere,
6:39
Speaker 1: you know. I was talking to my son about science
6:40
Speaker 1: fiction movies and he was asking me why I'm so
6:42
Speaker 1: picky about the science being right, and I was telling
6:44
Speaker 1: him that it was like a detective movie. You know,
6:47
Speaker 1: if you get a bunch of clues and they point
6:49
Speaker 1: you in one direction, and then at the end the
6:50
Speaker 1: clues didn't make sense or they're not consistent with the answer,
6:53
Speaker 1: then it feels pretty frustrating and disappointing. And I see
6:56
Speaker 1: every science fiction movie as sort of like a new mystery,
6:59
Speaker 1: like what are the rules of this universe? How does
7:02
Speaker 1: it all come together? What clues are we getting? And
7:05
Speaker 1: so I want the clues to be accurate and not
7:07
Speaker 1: just to lead you Australia to be nonsense and you
7:09
Speaker 1: don't want to like accidentally frame a neutrino for murder
7:13
Speaker 1: or something. I don't know. They're pretty sneaky, those neutrinos
7:17
Speaker 1: really weird, pretty suspicious. But you know, there is one
7:20
Speaker 1: organism which has inspired a lot of strange reactions in
7:23
Speaker 1: people to wonder whether or not it's intelligent, or whether
7:26
Speaker 1: or not it's structure reveals something about the nature of
7:29
Speaker 1: the universe. And this is very weird entity called the
7:31
Speaker 1: slime mold. And you know, my first interaction with the
7:34
Speaker 1: slime mold actually came from a listener email. We had
7:38
Speaker 1: an episode about the book Semiosis, which is a science
7:41
Speaker 1: fiction novel in which plants organize and become intelligent in
7:45
Speaker 1: sort of a strange way that's not exactly penetrable by
7:48
Speaker 1: human intelligence, but you know, they can act and they
7:50
Speaker 1: can think and they can plan in this novel. And
7:53
Speaker 1: one listener, Ian Hans Portman, from the UK, wrote to
7:56
Speaker 1: me and said that it reminded him of one of
7:58
Speaker 1: his favorite pets, which were slime molds, and would I
8:01
Speaker 1: be interested in him mailing me some example slime molds
8:06
Speaker 1: so of course I said, sure, please send me these
8:09
Speaker 1: crazy creatures via the post, and he did so. He
8:13
Speaker 1: sent us some slime molds via the mail. Because they're
8:16
Speaker 1: very hardy, right, they can survive a long time. And
8:18
Speaker 1: my wife grew them for a while, and then I
8:20
Speaker 1: think she threw them out and they ended up taking
8:22
Speaker 1: over our compost bin for a while. So they're out
8:25
Speaker 1: there now exploring southern California and gobbling up all the
8:29
Speaker 1: amazing treats that they can find. Wonderful. I'm sure that
8:33
Speaker 1: won't sort of come back to bide us and say,
8:36
Speaker 1: a hundred million years. But slime olds are fascinating because
8:40
Speaker 1: they are these tiny little creatures, but they also seem
8:42
Speaker 1: to exhibit some form of intelligence, and the way they
8:45
Speaker 1: organize themselves might provide clues as to where the whole
8:48
Speaker 1: universe organizes itself. The patterns of slime mold networks might
8:52
Speaker 1: reveal something which tells us about the structure of the
8:55
Speaker 1: universe and where all the dark matter is. And I
8:58
Speaker 1: guess where all the compost keeps Jupiter has been keeping. Yeah,
9:02
Speaker 1: maybe dark matter is just the compost of the universe,
9:05
Speaker 1: you know, it's just the universe is recycling would that
9:09
Speaker 1: make black holes the sort of uh incincreators of the
9:15
Speaker 1: universe universal garbage disposals. So I was curious if people
9:19
Speaker 1: had thought about this or understood that there might be
9:21
Speaker 1: a connection between weird, sticky blobs on forest floors and
9:25
Speaker 1: the structure of the universe on the grandest scale. So
9:28
Speaker 1: I went out to our cadre of Internet volunteers and
9:30
Speaker 1: ask them what they thought about a potential connection between
9:34
Speaker 1: slime molds and dark matter. So thanks to everybody who participated,
9:38
Speaker 1: and if you would like to get similarly puzzling questions
9:41
Speaker 1: via email from me, don't be shy, right to me
9:44
Speaker 1: two questions at Daniel and Jorge dot com. So before
9:47
Speaker 1: you hear these answers, think to yourself, what do you
9:50
Speaker 1: think slime molds might tell us about dark matter? And
9:53
Speaker 1: I have no idea what slim mode is, but I'm
9:57
Speaker 1: guessing it might be the movement of dark matter around
10:02
Speaker 1: the universe, and objects help discus and fluid it is
10:08
Speaker 1: where it fills in the gaps. I actually don't know
10:14
Speaker 1: slime molds. I know they can they've been shown to
10:18
Speaker 1: be able to compute stuff, but what that has to
10:24
Speaker 1: do with dark matter? I have no idea. I didn't
10:29
Speaker 1: I didn't expect to expect a question like this. I
10:32
Speaker 1: have no idea whatsoever slime molds. Uh, no, nothing, I've
10:39
Speaker 1: got absolutely nothing. Sorry, best I can do these lime
10:44
Speaker 1: molds and dark matter. I'm all in favor of mixing
10:48
Speaker 1: up stuff, but I don't see any connection between those two.
10:53
Speaker 1: Very curious to know what. I have no idea what
10:56
Speaker 1: slime molds have to do with dark matter, but I
10:58
Speaker 1: imagine they are growth or something in their molecular constitution
11:03
Speaker 1: that might be maybe affected by dark matter. I'm not sure.
11:07
Speaker 1: I have no idea. I have no idea what slime
11:10
Speaker 1: molds are. When I think of slime, I just think
11:13
Speaker 1: of the green goo. I'm sure that has nothing to
11:16
Speaker 1: do with what we're talking about. I don't know what
11:19
Speaker 1: they say about arma matter. Um. I just know that
11:24
Speaker 1: they try to map something. I don't do too much,
11:32
Speaker 1: too many details about it, but it is interesting. How
11:37
Speaker 1: close can can you get with this with this model?
11:43
Speaker 1: I don't know. Is there's something about slime molds that
11:45
Speaker 1: we just do not know, Like it's like the mystery
11:47
Speaker 1: mold of the universe. It's what holds all mold together.
11:52
Speaker 1: Ah Man, Maybe it just tells us there's more mystery
11:55
Speaker 1: here than we really thought there was, all right, So
11:57
Speaker 1: a lot of confusion in these answers. Not a lot
12:00
Speaker 1: of people have even heard of slime molds or had
12:02
Speaker 1: any idea what they might tell us about the universe.
12:04
Speaker 1: That surprised you, Katie, Yeah, yeah, I mean I love
12:08
Speaker 1: slime molds, so I feel like everyone should love them
12:12
Speaker 1: as well. Obviously they are in a way cute. I
12:16
Speaker 1: suppose I try to find the cuteness in every organism
12:21
Speaker 1: or I guess like globular cluster of organisms. So yeah,
12:25
Speaker 1: I really hope people gain some slime mold awareness through this.
12:31
Speaker 1: I'm glad that you're pro slime mold, that you're really
12:32
Speaker 1: thinking about what the slimes need. They need human representatives
12:36
Speaker 1: to really speak up for them, advocates. Yes, our interest
12:39
Speaker 1: here is not just to think about what the slime
12:42
Speaker 1: mold needs, but to try to solve the mysteries of
12:44
Speaker 1: the universe, to think about where in the universe everything
12:47
Speaker 1: is and how it got there and how we can
12:49
Speaker 1: learn about it. Yeah. Yeah, I I am really curious
12:53
Speaker 1: because slime molds are one of the most mysterious organisms
12:58
Speaker 1: on Earth that their behave year and what exactly is
13:01
Speaker 1: going on with them is really interesting, and it's relative.
13:06
Speaker 1: There's a lot of room to explore still, so there's
13:10
Speaker 1: a lot unknown about them. There are a lot of
13:11
Speaker 1: studies and a lot of controversy. So I feel like
13:15
Speaker 1: the fact they are just so already so mysterious, it's
13:19
Speaker 1: just very intriguing that if we unlock some of these
13:23
Speaker 1: mysteries of the slime mold, we may be able to
13:25
Speaker 1: unlock some of the mysteries of the universe exactly. Maybe
13:29
Speaker 1: slime molder aliens and they're here to tell us the
13:31
Speaker 1: secrets of the universe. They do look very alien like
13:34
Speaker 1: in just like they're sort of a blob, a growing blob.
13:38
Speaker 1: So if that is your image of an alien sort
13:41
Speaker 1: of a blob, I think there's been a few sort
13:44
Speaker 1: of be movies where an alien blob comes from outer
13:47
Speaker 1: space and then consumes people or takes over the world. Well,
13:51
Speaker 1: I'd love to talk about b movies with blob aliens.
13:54
Speaker 1: Let's first talk about the structure the universe, where everything
13:57
Speaker 1: is and where everything isn't because you probably know the
14:00
Speaker 1: universe is not just the stuff that we see out there.
14:03
Speaker 1: Of course, there are galaxies and there are stars, and
14:06
Speaker 1: there are planets, and there's huge clouds and gas and dust.
14:09
Speaker 1: But that only adds up to about five percent of
14:11
Speaker 1: all of the stuff in the universe. The rest of
14:13
Speaker 1: the universe is other stuff, stuff that we do not
14:16
Speaker 1: understand a huge chunk of that, Like is dark matter
14:22
Speaker 1: something we know is out there. We know it's matter,
14:25
Speaker 1: we know it's stuff, we know it has gravity, but
14:27
Speaker 1: we don't know what it's made out of. And all
14:30
Speaker 1: that just adds up to about of the universe. The
14:33
Speaker 1: other seventy percent of the energy density of the universe.
14:36
Speaker 1: If you took like a cubic light year of the
14:39
Speaker 1: universe and asked where is all the energy, seventy percent
14:42
Speaker 1: of that would be in something else called dark energy,
14:45
Speaker 1: which is accelerating the expansion of the universe, tearing it
14:48
Speaker 1: apart faster and faster every year. And while we'd love
14:51
Speaker 1: to dig into dark energy on every podcast because it's
14:53
Speaker 1: an amazing mystery, today we're focusing on sort of where
14:56
Speaker 1: is the stuff in the universe? Where is the matter
14:58
Speaker 1: by which we mean dark matter and normal matter. How
15:01
Speaker 1: do we even know that dark matter exists? If it's
15:05
Speaker 1: something that's so mysterious and so seemingly extremely difficult to
15:10
Speaker 1: like directly observe it. What are the signs that dark
15:14
Speaker 1: matter exists, Like, is it sort of a negative space
15:16
Speaker 1: scenario where we are able to see the dark matter
15:20
Speaker 1: based on the things around dark matter? Exactly, we can't
15:24
Speaker 1: see dark matter directly. The name dark matter itself is
15:27
Speaker 1: a little misleading because it makes you think of like
15:29
Speaker 1: a big dark cloud that would block your vision. But
15:32
Speaker 1: actually dark matter is more like invisible or transparent matter
15:36
Speaker 1: because light passes right through it doesn't give off any light,
15:39
Speaker 1: it doesn't reflect any light. You can't see it directly
15:42
Speaker 1: using light because it just doesn't interact with photons at all.
15:45
Speaker 1: And the only way that we can see it is
15:47
Speaker 1: through its gravitational effects on other things. And so that means,
15:50
Speaker 1: for example, that it holds galaxies together, because we think
15:53
Speaker 1: that all galaxies are swimming in these big dark matter
15:57
Speaker 1: halos that are compressing them and keeping them together as
16:00
Speaker 1: they spin really really fast. We also know that dark
16:03
Speaker 1: matter has played a huge role in determining the structure
16:06
Speaker 1: of the universe, Like why is there a galaxy here
16:08
Speaker 1: at all? It's because there was a big pool of
16:11
Speaker 1: dark matter that pulled together all these gas and dust
16:14
Speaker 1: to form stars. Without dark matter in the universe, that
16:17
Speaker 1: structure would take a lot longer to form, be like
16:20
Speaker 1: another ten billion years before the gravity of just the
16:23
Speaker 1: gas and the dust was able to pull it together
16:26
Speaker 1: to make stars. So dark matter really has shaped the
16:29
Speaker 1: universe even though we can't see it directly. So it's
16:32
Speaker 1: kind of like the invisible hand of the universe if
16:36
Speaker 1: we want to get all economics about it. But that
16:40
Speaker 1: is really interesting. Could you, I mean, if you gave
16:44
Speaker 1: me a spoonful of dark matter, like, could I feel it?
16:49
Speaker 1: Or would it just sort of destroy me? Would it
16:52
Speaker 1: start impacting the things around it? Would my office chairs
16:57
Speaker 1: start to float up and get sucked in around and
17:00
Speaker 1: are pushed around? What is that sort of physical attribute
17:04
Speaker 1: of the dark matter? Because my sense of matter is
17:07
Speaker 1: matter is a physical thing that impacts things physically, whereas
17:12
Speaker 1: energy differs from matter, and that it's not it's not
17:15
Speaker 1: like a it is it's hard for me to describe
17:19
Speaker 1: without the kind of reiterating the physics concepts. Yeah, it's
17:24
Speaker 1: a great question, but unfortunately, dark matter is not something
17:26
Speaker 1: that you can like put on your pizza. Dark matter
17:29
Speaker 1: interacts with you gravitationally, which means that it pulls on you.
17:32
Speaker 1: It tugs on you gravitationally, but because it doesn't interact
17:35
Speaker 1: with you using electromagnetism, it passes right through you, the
17:39
Speaker 1: same way that like neutrinos can. Neutrinos come from the
17:42
Speaker 1: Sun and they shoot through the Earth and they don't stop.
17:45
Speaker 1: They don't obey the boundaries of your body or the
17:48
Speaker 1: walls or the ground because they don't see them. The
17:51
Speaker 1: universe is transparent to them. They don't have that way
17:54
Speaker 1: to interact, so they just ignore that kind of matter
17:57
Speaker 1: and pass right through it. The same is true for
18:00
Speaker 1: dark matter, which remember, is not out there in the universe.
18:02
Speaker 1: It's here surrounding us. It's all around us. It's in
18:05
Speaker 1: this very room that you are in. But if a
18:08
Speaker 1: piece of dark matter flew right through your brain, you
18:10
Speaker 1: wouldn't notice, and either would it, because you two cannot
18:14
Speaker 1: interact except through gravity, which is super duper weak. The
18:18
Speaker 1: only way we can even know dark matter is there
18:20
Speaker 1: is when there are enormous, like galaxy sized blobs of
18:23
Speaker 1: it having gravitational effects on the visible matter. What you
18:27
Speaker 1: didn't see it was me with a broom trying to
18:29
Speaker 1: sweep out all the dark matter, as you told me
18:32
Speaker 1: that it's here with me right now, So like it's
18:34
Speaker 1: it's scattered throughout the universe. But then you can have
18:38
Speaker 1: like these big sort of blobs of it as well
18:41
Speaker 1: that have a stronger impact on their surroundings. Yeah, and
18:46
Speaker 1: these blobs have an amazing history that really shaped the
18:49
Speaker 1: whole structure of the universe. If you cast your mind
18:52
Speaker 1: back to the very very beginning of the universe, everything
18:55
Speaker 1: was filled with like an even smooth amount of energy.
18:58
Speaker 1: No spot was any different from any other spot, because like,
19:01
Speaker 1: why would any spot be special. The universe doesn't have
19:04
Speaker 1: a center. No location is different from any other location,
19:07
Speaker 1: so everything is the same. But if everything is the same,
19:09
Speaker 1: then gravity can't really do anything because it's being tugged
19:12
Speaker 1: in every direction the same amount. But what happened very
19:15
Speaker 1: early on was that you've got quantum fluctuations. You know,
19:18
Speaker 1: pairs of particles were created out of the vacuum just randomly,
19:22
Speaker 1: energy converted into matter and back, and so some places
19:25
Speaker 1: were a little denser than others. And then the universe
19:27
Speaker 1: expanded very very rapidly. So those little quantum fluctuations, which
19:32
Speaker 1: normally you would never notice, I would have no gravitational
19:34
Speaker 1: impact got blown up to enormous proportions. The early universe
19:38
Speaker 1: expansion is like a factor of tend to the thirty.
19:42
Speaker 1: That's ten with thirty zeros in front of it. Something
19:45
Speaker 1: used to be like a nanometer is now light years across.
19:48
Speaker 1: And so then gravity had something to hang onto. You
19:52
Speaker 1: could say, oh, this spot here is denser than its
19:54
Speaker 1: neighboring spots. I'm gonna start tugging on those particles. And
19:57
Speaker 1: that's how structure was formed. It it was the sea
20:00
Speaker 1: the gravity needed to grab onto. And then you fast
20:03
Speaker 1: forward some millions of years and gravity has gathered that
20:05
Speaker 1: together into these huge sheets of dark matter. And where
20:09
Speaker 1: those sheets overlap with each other, you get even stronger densities,
20:13
Speaker 1: and those we call filaments. And where those filaments intersect
20:16
Speaker 1: with other filaments are the most powerful densities. And those
20:20
Speaker 1: are the intersections where galaxies form. Because you get this
20:23
Speaker 1: intersection with a lot of dark matter, and it's like
20:26
Speaker 1: a lake with all the filaments sort of like contributing
20:28
Speaker 1: to it. Everything is flowing towards the densest spots, and
20:32
Speaker 1: that's where galaxy is formed. So these sheets and these
20:35
Speaker 1: filaments of dark matter really have determined the whole structure
20:38
Speaker 1: of the universe. Well, so we we kind of started
20:41
Speaker 1: out as a puree and then became like Campbell's chunky
20:45
Speaker 1: chicken noodle soup. But yeah, that is I mean, even
20:48
Speaker 1: the way you describe it does sound very biological. Things
20:52
Speaker 1: kind of coagulating and coalescing and pulling on each other.
20:57
Speaker 1: It sounds like something like milk curdling, which is really interesting.
21:02
Speaker 1: So dark matter has this huge impact on the universe.
21:08
Speaker 1: How do we How have we kind of observed that happening.
21:12
Speaker 1: It's a great question because dark matter is kind of invisible.
21:15
Speaker 1: So some of this is a little bit theoretical. Some
21:18
Speaker 1: of this is like running simulations and saying, if we
21:20
Speaker 1: put all these rules into the universe, what kind of
21:22
Speaker 1: universe do we get? Do we get the kinds of
21:25
Speaker 1: structure that we see today. But of course we'd like
21:28
Speaker 1: to see the actual structure. We'd like to look out
21:30
Speaker 1: into the universe and observe how things really are. And
21:34
Speaker 1: the fascinating thing about these filaments is like connections between galaxies. Right,
21:38
Speaker 1: Like our galaxy is floating in space and the's another
21:41
Speaker 1: galaxy nearby Andromeda. But there's not just empty space between
21:45
Speaker 1: US and Andromeda. There's an invisible filament of dark matter,
21:49
Speaker 1: but there's also a filament of normal matter. Not all
21:52
Speaker 1: of the gas and the dust ended up in the galaxies,
21:55
Speaker 1: a lot of it is actually between the galaxies. And
21:57
Speaker 1: so for example, like only ten percent of the matter
22:00
Speaker 1: is in galaxies, Like if you take a random proton
22:03
Speaker 1: in the universe, only one other ten are in the
22:06
Speaker 1: galaxy right now. Another fifty percent of them are around
22:09
Speaker 1: the galaxies, like in a big blob of gas that
22:12
Speaker 1: hasn't yet fallen in but might soon. And the rest
22:14
Speaker 1: of it, like of the stuff in the universe, we're
22:17
Speaker 1: not even sure where it is. It might be in
22:20
Speaker 1: these filaments between galaxies. Might be that there's huge amounts
22:24
Speaker 1: of gas lying along these filaments made by dark matter,
22:27
Speaker 1: but it's hard to tell. It's hard to see these
22:29
Speaker 1: things because the gas is so faint. That's so interesting.
22:33
Speaker 1: So we've got like these almost these like tendons or
22:37
Speaker 1: sort of strings that are connecting these galaxies and but
22:41
Speaker 1: not not just connecting them, but also influencing the matter
22:45
Speaker 1: around them by by pulling on it. Can we actually
22:48
Speaker 1: like when say we got just a really good telescope,
22:52
Speaker 1: could we actually see these filaments, or would since dark
22:57
Speaker 1: matter is invisible, would we not really see anything. We
23:01
Speaker 1: can see them a little bit, but it's very unlimited.
23:04
Speaker 1: So these filaments have lots of gas in them, and
23:06
Speaker 1: if the gas is hot, meaning the particles are moving
23:09
Speaker 1: really really fast, then they emit light. They emit X rays,
23:12
Speaker 1: for example, and we can see that with our X
23:14
Speaker 1: ray telescopes, And you might be confused, like, how can
23:17
Speaker 1: this gas be hot? We're talking about something in deep
23:19
Speaker 1: space between galaxies or remember that things can be hot,
23:23
Speaker 1: but they can also be dilute. It's not like hot
23:25
Speaker 1: in the sense that you could like hang out there
23:26
Speaker 1: in your swimsuit and have a nice time. You would
23:28
Speaker 1: definitely freeze if somebody dumped you in these filaments because
23:32
Speaker 1: there isn't a lot of heat there. But there are
23:34
Speaker 1: vast moving particles and those emit X rays. So we
23:38
Speaker 1: have seen these filaments directly. The problem is that it's
23:41
Speaker 1: hard to see the whole cosmic web using these X rays,
23:44
Speaker 1: because where at one little spot of it, it's easiest
23:47
Speaker 1: to only see their really close parts. We'd like to
23:49
Speaker 1: see the whole map of the universe. Another way we
23:51
Speaker 1: can look at these is to see how light is
23:53
Speaker 1: absorbed as it comes to us from things behind these filaments.
23:58
Speaker 1: For example, quasars are very very bright sources of light.
24:02
Speaker 1: They are black holes that have swirling gas around them,
24:05
Speaker 1: and that gas is being squeezed by the tidal forces
24:08
Speaker 1: of the black hole and heated up to incredible temperatures
24:11
Speaker 1: and emitting these very very bright pencil beams of light.
24:14
Speaker 1: And when they pass through the filaments, some frequencies of
24:17
Speaker 1: light get absorbed based on what's in them. So we
24:20
Speaker 1: can use this to sort of like X ray these
24:22
Speaker 1: filaments to say, oh, here's one and it has some
24:25
Speaker 1: hydrogen in it. Oh, and look it also has some
24:26
Speaker 1: iron in it. How did that get there? So we
24:28
Speaker 1: can see sort of the nearest ones using X rays,
24:31
Speaker 1: and we can have a few like pencil beams through
24:33
Speaker 1: the universe to give us a sense for where some
24:35
Speaker 1: of the other ones are, but we don't have a
24:37
Speaker 1: great way in general to figure out where these filaments are.
24:41
Speaker 1: That's really interesting, I mean, it seems like basically trying
24:45
Speaker 1: to detect these filaments, it's like trying to sort of
24:48
Speaker 1: toss a marble at another marble, like another a mile
24:52
Speaker 1: away and hit it. So by observing sort of like
24:55
Speaker 1: how the effect it's having on light as it's passing through.
24:59
Speaker 1: We can kind of tell a little bit about them. Yeah,
25:03
Speaker 1: but you need a source of light, You need like
25:04
Speaker 1: a conveniently placed quasar to show you where these things are.
25:08
Speaker 1: It's sort of like the way a laser beam in
25:10
Speaker 1: a dark room will show you where the dust is,
25:13
Speaker 1: but it won't show you where the dust is where
25:15
Speaker 1: the laser is not pointing, you know. And so if
25:17
Speaker 1: you have a few lasers to a room, you can
25:18
Speaker 1: see where the dust motes are, but most of the
25:20
Speaker 1: room is still invisible to you. Wow. So we're really
25:23
Speaker 1: just relying on luck to be able to see any
25:28
Speaker 1: any sign of these filaments. Yeah, and it's a huge
25:31
Speaker 1: mystery how much gas is in these filaments. You know,
25:34
Speaker 1: we're talking about a big chunk of the universe's budget
25:37
Speaker 1: is like unexplained. And people are used to the idea
25:40
Speaker 1: that dark matter is sort of like this missing chunk
25:42
Speaker 1: of the universe and that five percent of the universe
25:44
Speaker 1: is our kind of matter. Now we're talking about like
25:47
Speaker 1: of that five percent, not some mysterious form of matter,
25:50
Speaker 1: but just like normal matter, protons and neutrons. We can't
25:54
Speaker 1: explain where all that stuff is, like a huge chunk.
25:57
Speaker 1: But a third of the visible universe, the stuff we're
26:00
Speaker 1: supposed to understand, is gone missing. This is called the
26:03
Speaker 1: missing Baryon problem, and so understanding if it's in these
26:06
Speaker 1: filaments could really help us get a clear picture of
26:09
Speaker 1: you know, the whole universe. I mean, have we tried
26:12
Speaker 1: printing out posters with missing baryon call this number reward.
26:18
Speaker 1: We've tried sending traps, you know, with nice hasty Russian
26:21
Speaker 1: pizzas on them, but they don't seem interested. So let
26:25
Speaker 1: me go grab delicious pizza right now. And when we
26:30
Speaker 1: get back, why don't we talk a little bit about
26:33
Speaker 1: those slime molds and uh see what they're about. And
26:36
Speaker 1: now that we've learned a little more about dark matter,
26:52
Speaker 1: all right, and we are back and I have just
26:55
Speaker 1: polished off this wonderful slime mold pizza. Actually, no, don't
27:01
Speaker 1: do that. Don't eat unidentified slime molds. But Daniel, I mean,
27:05
Speaker 1: you have gotten to know a slime mold personally, so
27:09
Speaker 1: you've actually had a personal relationship with a slime old.
27:12
Speaker 1: What did you learn in that relationship with that slime mold?
27:16
Speaker 1: The listener sent you, Um, I learned the slime molds
27:19
Speaker 1: are not as slimy as you might expect. You know,
27:22
Speaker 1: they're one of these weird creatures with multiple stages in
27:25
Speaker 1: their life that look very different. You know, like how
27:27
Speaker 1: caterpillars and butterflies are in the same creature, just in
27:30
Speaker 1: a different part of its life, and slime molds only
27:33
Speaker 1: are slimy and like one mode of their life. So
27:36
Speaker 1: sometimes it can look just sort of like a normal
27:38
Speaker 1: weird blob or like an actual mushroom or something sort
27:41
Speaker 1: of crawling its way across your countertop. So it's a
27:44
Speaker 1: little bit underslimed. Yeah. That is one of the most
27:48
Speaker 1: baffling things about slime molds is they have a life
27:52
Speaker 1: cycle that's just very confusing, and it's almost like they
27:57
Speaker 1: turned into completely different sort of organisms throughout their life.
28:02
Speaker 1: I mean, this is not something unheard of for other animals.
28:06
Speaker 1: Of course, you know, the first person to see a
28:09
Speaker 1: caterpillar and then see a butterfly, I would have no
28:11
Speaker 1: idea this is the same animal. It goes through these
28:15
Speaker 1: very different stages, and it goes through a crawling stage
28:19
Speaker 1: and then the chrysalists this immobile, sessile stage and then
28:23
Speaker 1: a flying stage. So that is must have been very
28:26
Speaker 1: mystifying for the first people to to see these organisms.
28:30
Speaker 1: And of course slime molds are also really mysterious, and
28:35
Speaker 1: we're learning so much about them even now. But yeah,
28:39
Speaker 1: so the first thing I think to know about them
28:42
Speaker 1: is that it is not a single organism. It is,
28:46
Speaker 1: generally speaking, these slime molds that you you will see
28:50
Speaker 1: like this kind of blob or splat mark is going
28:54
Speaker 1: to be a amalgamation of a bunch of individual organisms
29:00
Speaker 1: that are all interacting with each other, like an ant
29:03
Speaker 1: colony or a b colony, but on a microscopic scale
29:07
Speaker 1: and smooshed together. So it's like a community you're saying,
29:10
Speaker 1: not just like a single organism. Yeah, I mean it.
29:14
Speaker 1: They will have stages in their life where they will
29:16
Speaker 1: be sort of a single organism, but yeah, the most
29:20
Speaker 1: of their life, and indeed, like they when we can
29:24
Speaker 1: actually see this thing that looks like a single organism,
29:28
Speaker 1: that is a cluster of these single celled organisms. So
29:34
Speaker 1: they used to be classified as fun guy. You know,
29:38
Speaker 1: we've talked about the mushroom pizza and everything, but that's
29:42
Speaker 1: actually a somewhat outdated classification. So now they are just
29:48
Speaker 1: kind of their own thing. It's a very strange classification
29:52
Speaker 1: because it is like eight hundred species who are all
29:58
Speaker 1: sort of loose related phylogenetically, but kind of lumped together
30:04
Speaker 1: as It's like the extra pile in terms of organisms,
30:07
Speaker 1: where we try to make these classifications, and now we
30:11
Speaker 1: have this group of kind of weird those that we
30:14
Speaker 1: don't know how else to classify them, so they all
30:17
Speaker 1: get lumped together as slime molds. I mean, if I
30:21
Speaker 1: just google slime mold, for example, I see a bunch
30:23
Speaker 1: of interesting things. I see some weird yellow things with
30:27
Speaker 1: like what looks like veins in them, you know, these
30:29
Speaker 1: like transport networks. And then also see like weird purple
30:33
Speaker 1: blobs and weird pink things that look like mushrooms, and
30:36
Speaker 1: you know some things that just really do look like
30:38
Speaker 1: gelatinous cubes taking over the earth. You know. So are
30:41
Speaker 1: you saying this is sort of like a biological frontiers,
30:43
Speaker 1: not something we really understand how they evolved and how
30:46
Speaker 1: they're related to, sort of like a grouping of mysterious
30:49
Speaker 1: objects that are sort of similar to each other. I mean,
30:52
Speaker 1: I wouldn't say it's completely mysterious. We have I mean
30:57
Speaker 1: researchers have discovered a lot about them, but it is
31:00
Speaker 1: a little more of a wild West situation than maybe
31:04
Speaker 1: some other organisms that we've studied. So basically they are
31:08
Speaker 1: What we do know is they are eukaryotes like humans, plants,
31:11
Speaker 1: and animals. These are all eukaryotes, but they are protests.
31:15
Speaker 1: So a protest is any kind of eukaryote that is
31:19
Speaker 1: not an animal, plant, or fungus. So it's just basically
31:23
Speaker 1: we know definitely what they aren't. So we know that
31:28
Speaker 1: they are not animals, plants, or fungus, so we kind
31:31
Speaker 1: of give them their own group. But in terms of
31:34
Speaker 1: figuring out how they are related at each of these
31:38
Speaker 1: slime old species, you know, that is still a growing
31:42
Speaker 1: topic of research um And in fact, that a slime
31:46
Speaker 1: old you google that yellow one probably is the Phicerum polycephalum,
31:52
Speaker 1: which is that yellow blob. And I think we've actually
31:57
Speaker 1: shot that species of slime mold into space to see
32:03
Speaker 1: exactly what is going to happen with it in a
32:07
Speaker 1: low gravity setting. So do you think that they're going
32:10
Speaker 1: to land on the Moon and partner with tar degrades
32:12
Speaker 1: to build the next alien empire? I fear what would
32:15
Speaker 1: happen if they partnered with tar degrades. So they have
32:20
Speaker 1: a very strange life cycle. So during one stage of
32:24
Speaker 1: its life, it's an a cellular organism. So instead of
32:28
Speaker 1: actually like at least for this phi serum paul cephalum,
32:32
Speaker 1: so it differs depending on the slime mold, but like
32:36
Speaker 1: for that specific slime mold, it just has like one
32:39
Speaker 1: kind of cell that instead of just like dividing into
32:43
Speaker 1: multiple cells as it grows, it's just like one big
32:46
Speaker 1: kind of goopy blob. But you know, other types of
32:49
Speaker 1: slime molds are a group of individual you know, cellular organisms,
32:54
Speaker 1: and they can really a mass to large sizes. So
33:01
Speaker 1: some can be up tom and mass and they can
33:07
Speaker 1: be measured in square meters in size, which is alarming.
33:11
Speaker 1: Twenty ms. Wow, that's like big enough to tackle somebody.
33:16
Speaker 1: I mean, has a slime mold ever taken down a person?
33:18
Speaker 1: I don't think they have, just because they move so slowly.
33:24
Speaker 1: What about like a cartoonist that was like sleeping in
33:26
Speaker 1: really late, and do you think it could eat Jorge
33:29
Speaker 1: if he was not paying attention? I think maybe, Yeah,
33:31
Speaker 1: Jorge was staying up late at night finishing a cartoon
33:35
Speaker 1: and kind of slept in. Maybe all right, well, let's
33:38
Speaker 1: hope somebody warns him. That's why you set alarm clocks
33:41
Speaker 1: so your local slime mold won't devour you as you
33:44
Speaker 1: sleep in. So I think slime molds are fascinating because
33:47
Speaker 1: they have these weird life cycle and biologically they're really interesting.
33:50
Speaker 1: But also they seem to be able to like to
33:52
Speaker 1: do things. And you talked about slime molds at these
33:54
Speaker 1: individual entities which sometimes come together to act communally, And
33:59
Speaker 1: it's amazing to me when they can do things as
34:01
Speaker 1: a group that an individual couldn't do. Some example, these
34:04
Speaker 1: things like learning. Yeah. Yeah, So they can either live
34:08
Speaker 1: freely or they will join together to form a multicellular aggregate.
34:14
Speaker 1: And this is where, yeah, it gets really weird and
34:17
Speaker 1: really interesting. So like there have been multiple studies to
34:21
Speaker 1: see how they act as a group. I mean, you know,
34:24
Speaker 1: when you think about something like an ant colony and
34:27
Speaker 1: you leave a piece of food out, the ant colony
34:30
Speaker 1: is going to sort of act as a group. They'll
34:32
Speaker 1: form these lines of ants guided by pheromones to go
34:37
Speaker 1: pick up this food. But we can still kind of
34:39
Speaker 1: see these individual ants for sly molds when they get
34:43
Speaker 1: together they're so small. What we're seeing is basically a
34:46
Speaker 1: blob or a slug seeming to act as one organism,
34:51
Speaker 1: even though it's made up of many individual organisms. So
34:55
Speaker 1: they will sometimes when they detect food, they will come
34:59
Speaker 1: to other and kind of act together as if they
35:03
Speaker 1: are a single organism. And there was actually a study
35:09
Speaker 1: that was done that was like kind of trying to
35:13
Speaker 1: see like whether slime old could figure out how to
35:17
Speaker 1: get to food, and they would put these little oat
35:21
Speaker 1: flakes around in a little dish with the slime mold,
35:24
Speaker 1: and the slime wold was able to relatively efficiently figure
35:30
Speaker 1: out how to um get to these oat flakes, and
35:35
Speaker 1: it actually somewhat resembled like the Tokyo train system because
35:43
Speaker 1: it was finding out roots to the oat flakes in
35:48
Speaker 1: a relatively efficient way. I think that's super fascinating and
35:52
Speaker 1: that connects to the idea we were talking about at
35:54
Speaker 1: the top of the episode about having similar mathematical problems
35:57
Speaker 1: on different scales. You know, people want or like how
36:00
Speaker 1: could a slime mold replicate the Tokyo rail network? What
36:03
Speaker 1: does that mean? Well, think about like how you build
36:05
Speaker 1: a rail network. You want it to be efficient, you
36:07
Speaker 1: want to be able to get from one place to
36:09
Speaker 1: the other with a minimal number of connections and the
36:11
Speaker 1: shortest distances. So you build this network between your cities
36:15
Speaker 1: and the slime mold, it seems like it's sort of
36:17
Speaker 1: solving a similar problem. It's like, if I have food
36:20
Speaker 1: in these locations, then where should I build my connections
36:23
Speaker 1: between them so I can most efficiently move my nutrients
36:25
Speaker 1: around and get my cells from one food source to
36:28
Speaker 1: the next. You know, where should I focus my energies.
36:31
Speaker 1: And it's amazing that the network that comes out of that,
36:33
Speaker 1: if you place like the oats in the same structure
36:36
Speaker 1: as like the Japanese cities, that it basically replicates the
36:39
Speaker 1: Tokyo rail network because it suggests that it's solving a
36:43
Speaker 1: mathematical problem, not like it's got a little chalkboard in there,
36:47
Speaker 1: but that effectively it's doing computing. You know, what is
36:50
Speaker 1: a computer other than like a physical representation of a
36:52
Speaker 1: mathematical problem. You get the universe in terms of transistors
36:56
Speaker 1: or whatever to solve a problem you've represented symbolically. And
37:00
Speaker 1: that seems like that's what the slime mold is doing.
37:02
Speaker 1: It's like basically doing slime mold computing. It's solving this
37:06
Speaker 1: optimization problem. Yeah. Actually, some researchers are interested in studying
37:11
Speaker 1: whether it could be used to build like a bio
37:14
Speaker 1: computer and use the slime mold to form these logic
37:18
Speaker 1: gates in a biocomputer, so instead of using you know,
37:22
Speaker 1: a circuit board, you would have a gooey, living sort
37:26
Speaker 1: of bioboard. Yeah, you can form computers out of all
37:29
Speaker 1: sorts of stuff. You know, people think about computers as
37:32
Speaker 1: like transistors and switches flipping, and that is one way
37:35
Speaker 1: to use a computer, one way to design a computer.
37:37
Speaker 1: But any time that you build something which solves a
37:40
Speaker 1: math problem where you're using the physical universe to represent
37:44
Speaker 1: your problem again an answer effectively, that's a computer. And
37:47
Speaker 1: so yeah, you could represent a computational problem as a
37:51
Speaker 1: challenge for a slime mold where the answer is how
37:53
Speaker 1: the slime mold builds its network, which is pretty cool.
37:57
Speaker 1: I also really like these studies that show that slime
37:59
Speaker 1: molds can like learn, and remember they had these experiments
38:02
Speaker 1: where they were basically torturing slime molds every ten minutes
38:06
Speaker 1: on the hour. They would like cool it downs. It
38:09
Speaker 1: was uncomfortable for the slime molds and the slime wolds
38:11
Speaker 1: would like react to that, and then when they stopped
38:14
Speaker 1: doing it, they took a break. The slime molds anticipated
38:17
Speaker 1: it anyway, They were like, oh, is it going to
38:18
Speaker 1: get cold? And they reacted before the cold snap would come.
38:22
Speaker 1: Would suggest that they have like some internal clock or something,
38:25
Speaker 1: some way to keep track of time and anticipate what's
38:28
Speaker 1: going to happen based on what's happened to them before.
38:31
Speaker 1: That's incredible to me. Yeah, that's absolutely so strange because
38:36
Speaker 1: it is a question of exactly how do they store
38:40
Speaker 1: that kind of data, right, Like how are they storing
38:43
Speaker 1: this memory of the cold snaps? And I don't mean
38:47
Speaker 1: memory in terms of like a human memory like thinking
38:50
Speaker 1: back to something, but how a computer might store memories.
38:53
Speaker 1: So it is really it's spooky, it's really strange, And
38:58
Speaker 1: I think comparing it to accume puter is so apt
39:01
Speaker 1: because at this point, in terms of how we've developed computers,
39:04
Speaker 1: computers don't probably have a sort of conscious understanding or
39:09
Speaker 1: or a cognitive system like It's AI is still a
39:14
Speaker 1: pretty distant goal at this point. And so sometimes these
39:18
Speaker 1: slime olds will do things that make it seem like
39:21
Speaker 1: they are behaving in this very like conscious way or
39:27
Speaker 1: even altruistic way, but then when you look at the
39:30
Speaker 1: mechanisms behind it, it's actually this weird just probability maths.
39:36
Speaker 1: So slime olds like this study you mentioned with the
39:40
Speaker 1: researchers just torturing them when they are behaving as a
39:43
Speaker 1: collective as that mass, they will try to avoid hostile
39:48
Speaker 1: environments and get out of it. And one way they
39:51
Speaker 1: can do that is they will actually, like if they
39:54
Speaker 1: are on an environment and they want to kind of
39:58
Speaker 1: make sure that there's spores will be able to get
40:02
Speaker 1: to another place, they will form a slug and then
40:06
Speaker 1: that slug will stop somewhere and then will grow a
40:11
Speaker 1: stock like a plant, and then form like a fruiting
40:14
Speaker 1: body at the end that releases these slime old spores
40:19
Speaker 1: that can then go colonize another area. And it seems
40:24
Speaker 1: like the because it remember this is made out of
40:27
Speaker 1: a bunch of individuals. The ones that are like on
40:31
Speaker 1: the base of the stock or forming the stock, the
40:34
Speaker 1: ones that are not at the fruiting body that get
40:36
Speaker 1: to release their spores. It seems like they are sacrificing
40:40
Speaker 1: for their comrades to be able to get to the
40:44
Speaker 1: tops where they can release their spores, but in fact
40:48
Speaker 1: they are probably not acting altruistically. It is simply sort
40:53
Speaker 1: of a probability distribution where they are all trying to
40:57
Speaker 1: climb up to the top, and only some can reach
41:01
Speaker 1: the top. But as they are all collectively trying to
41:04
Speaker 1: make this climb, they happen just by the sort of
41:08
Speaker 1: the the probability distribution of how these slime molds are
41:11
Speaker 1: going to stack up they form the stock and this
41:14
Speaker 1: fruiting body, and it's just it's purely math. There's no
41:18
Speaker 1: slime mold cooperation or camaraderie going on. What is it
41:22
Speaker 1: like to be a slime mold? Will never know, but
41:24
Speaker 1: it's amazing that they have something that seems like an intelligence,
41:28
Speaker 1: ability to learn, to remember, to anticipate, though they have
41:31
Speaker 1: no central processing unit. There is no brain to these things.
41:34
Speaker 1: As you say, It all just emerges from the operations
41:37
Speaker 1: of these individual entities following local rules. That's really incredible
41:41
Speaker 1: to me. So let's take another break and we get back.
41:44
Speaker 1: We'll talk about how slime molds and the slime mold
41:47
Speaker 1: computing problems that they solve might give us a clue
41:51
Speaker 1: about the whole structure of the universe and where the
41:54
Speaker 1: dark matter is I have to hear this. All right,
42:09
Speaker 1: we're back and it was my turn to go off
42:12
Speaker 1: and polish a pizza. But I imagine that I'm getting
42:14
Speaker 1: over here in southern California are not really as you know,
42:17
Speaker 1: amazing as the ones you get over there. How far
42:20
Speaker 1: are you from a really excellent pizza if you want
42:22
Speaker 1: to go from zero to pizza Katie, how long does
42:24
Speaker 1: it take you? Well, there's a really good, like for
42:26
Speaker 1: catcha pizza place that's maybe a like five minute walk
42:31
Speaker 1: for me, and then yeah there's and then there's another
42:33
Speaker 1: just traditional pizza place that's maybe a seven minute walk.
42:37
Speaker 1: Uh so yeah, you know what, if you're a human
42:40
Speaker 1: and you want to live the slime old life of
42:42
Speaker 1: trying to find the shortest distance between two points, finding
42:46
Speaker 1: out a walkable city is a way to go because
42:49
Speaker 1: you can just walk right to a pizza place. If
42:51
Speaker 1: I live there, then I think the map of my
42:53
Speaker 1: walking around with follow the slime old map of the city.
42:55
Speaker 1: You know, the efficient paths between pizza joints. Yeah, your
42:58
Speaker 1: your oat flakes would be all the pizza joints around here. Yeah.
43:04
Speaker 1: So we've been talking about the mystery of the structure
43:07
Speaker 1: the universe. Where is some of the missing stuff in
43:10
Speaker 1: the universe, the normal matter, the protons, the neutrons, the electrons,
43:13
Speaker 1: A lot of that might be between galaxies, but we
43:16
Speaker 1: can't see it directly. We also suspect that there are
43:19
Speaker 1: filaments of dark matter, these tendrils between galaxies that feed
43:23
Speaker 1: new matter into the dark matter haloes and connect us
43:25
Speaker 1: and show us sort of the history of where things
43:28
Speaker 1: split apart, but we can't see them directly. And now
43:30
Speaker 1: we have, on the other hand, this sort of slime
43:32
Speaker 1: mold computer that lets us think about networks and how
43:35
Speaker 1: to build them efficiently. So you might be wondering, like,
43:38
Speaker 1: what do these things have in common? There were some
43:41
Speaker 1: researchers in Santa Cruz I had an idea for how
43:44
Speaker 1: to use slime molds to build a map of these tendrils,
43:47
Speaker 1: these cosmic filaments. The idea actually starts with galaxies. You know,
43:51
Speaker 1: if you want to know where the filaments are, you
43:52
Speaker 1: want to know where the connections are between galaxies. Instead
43:55
Speaker 1: of looking for the filaments directly, why not just look
43:58
Speaker 1: for the galaxies because galaxy are something that we can see.
44:01
Speaker 1: Galaxies are like the nodes of this network, right, we
44:05
Speaker 1: can see them because they generate a lot of light.
44:07
Speaker 1: They have billions and billions of stars in them. We
44:09
Speaker 1: could see them across the universe. And there's a huge
44:12
Speaker 1: number of galaxies, right, quasars that we used to see
44:15
Speaker 1: the filaments when they shoot these like pencil rays of
44:18
Speaker 1: light and we can see them highlighting the filaments. Those
44:21
Speaker 1: are pretty rare. There aren't that many quasars in the universe.
44:24
Speaker 1: But galaxies are goodness because if there were too many quasars,
44:28
Speaker 1: that would mean a bunch of black holes that we
44:30
Speaker 1: would all get be getting sucked into. Yeah, an incredible radiation.
44:35
Speaker 1: But you know, if you hold up your finger, then
44:37
Speaker 1: like the size of your finger nail, for example, the
44:41
Speaker 1: size of your fingernail has like a million galaxies behind
44:44
Speaker 1: it just in the observable universe. Like if the universe
44:47
Speaker 1: is infinite, there's an infinite number of galaxies behind it,
44:50
Speaker 1: but just in the part that we can see. If
44:51
Speaker 1: you like focused hubble on that one spot in the sky,
44:55
Speaker 1: there'd be a million galaxies each with hundreds of billions
44:58
Speaker 1: of stars. You know, it's just it's mind boggling the
45:00
Speaker 1: hole this in your mind, but it's a really good
45:03
Speaker 1: way to get a sense for what the network is.
45:05
Speaker 1: It's like asking, we want to know where the trains run.
45:08
Speaker 1: Why don't you start out by looking for the stations
45:10
Speaker 1: and then figure out where the trains run in between
45:13
Speaker 1: the stations. Just don't stand in between the stations on
45:16
Speaker 1: the railroad tracks with your camera because that's probably not
45:20
Speaker 1: a good idea exactly. So that's the easy part is
45:23
Speaker 1: to figure out where the galaxies are. We spend a
45:25
Speaker 1: lot of time looking at galaxies. We have big catalogs
45:28
Speaker 1: of where galaxies are. But these folks are wondering, well,
45:31
Speaker 1: if you know where the galaxies are, does that tell
45:33
Speaker 1: you necessarily where the filaments are. You can't just draw
45:35
Speaker 1: a line between every pair of galaxy. You'd have like
45:38
Speaker 1: lines everywhere, Right, These filaments tend to cluster together places
45:42
Speaker 1: of larger mass. These filaments tend to form between the
45:44
Speaker 1: larger clusters of galaxy, and they form between the neighbors.
45:47
Speaker 1: There's a bit of an optimization problem here, right, Like
45:50
Speaker 1: how do you find the filaments? You need to explain
45:53
Speaker 1: the galaxy clusters that we have. You can't just spread
45:56
Speaker 1: them everywhere. And so folks have this idea. They're like,
46:00
Speaker 1: maybe we need to use slime mold computing to find
46:03
Speaker 1: out what is the optimal way to place filaments between
46:07
Speaker 1: the galaxies that we can see to figure out where
46:10
Speaker 1: those filaments probably are. So in order for that to work,
46:14
Speaker 1: the filaments, the dark matter filaments would have to have
46:18
Speaker 1: some kind of behavioral similarity to slime molds. So filaments
46:23
Speaker 1: have that push, pull, attraction and repulsion sort of characteristics.
46:29
Speaker 1: And is that sort of the connection with slime old.
46:33
Speaker 1: So if slime old has like an attraction to food
46:37
Speaker 1: and uh, sort of a wanting to avoid scientists trying
46:41
Speaker 1: to torture it, what are sort of the analogous behaviors
46:45
Speaker 1: of dark matter filaments. Well, it's all gravity, right. Dark
46:49
Speaker 1: matter creates those galaxies where there is more dark matter,
46:53
Speaker 1: then you get more dark matter halos and you get
46:55
Speaker 1: more bowls for galaxies to form in. So there's a
46:58
Speaker 1: tight connection between where the filaments are and where the
47:01
Speaker 1: galaxies formed sort of like support and encourage and create
47:04
Speaker 1: each other. So that's the push, right, They helped create
47:07
Speaker 1: each other, and there's also a pull they pull on
47:09
Speaker 1: each other. They sort of like tug on each other
47:11
Speaker 1: to make each other more compact. And so instead of
47:14
Speaker 1: just like spreading out in every direction. The dark matter
47:17
Speaker 1: pulls itself into these halos and into these filaments between them,
47:21
Speaker 1: and so that's why it's sort of like a push
47:23
Speaker 1: and a pull, as you say, like an optimization problem.
47:25
Speaker 1: You can't just spread out everywhere. You need to figure
47:27
Speaker 1: out like what is the best arrangement of dark matter?
47:30
Speaker 1: If I give you some dark matter, how would you
47:32
Speaker 1: sprinkle it around the universe to create the galaxy map
47:36
Speaker 1: that we see. What's the best place to put it?
47:38
Speaker 1: And so they discover that slime bolds could help us
47:40
Speaker 1: figure this out if they turn this like dark matter
47:44
Speaker 1: filament problem into a food problem. So they did this,
47:47
Speaker 1: of course in simulation. They didn't use real slime molds,
47:50
Speaker 1: So they didn't put a pile of slime mold next
47:53
Speaker 1: to a powerful telescope and say, what do you think?
47:55
Speaker 1: What would you guys do? You guys are in charge?
47:57
Speaker 1: Tell us where to look? And that's scenario. What would
48:00
Speaker 1: how would you behave? So what they do is they
48:03
Speaker 1: put blobs of simulated the slime mold where they see
48:06
Speaker 1: the galaxies, and then they simulated slime molds send out
48:09
Speaker 1: tendrils in every direction and if it finds another galaxy,
48:13
Speaker 1: then it strengthens that connection. And so this is the
48:15
Speaker 1: part where it's like simulating how a slime mold explores
48:19
Speaker 1: its space. It's sending out tendrils and looking for stuff,
48:22
Speaker 1: and when it's successful, a slime mold will build a
48:24
Speaker 1: stronger network. That's how it replicated, for example, the Tokyo
48:27
Speaker 1: train map. And so in the universe, these simulated slime
48:30
Speaker 1: molds start from galaxies and when they find other galaxies
48:34
Speaker 1: and they like enhance that connection between them. So there
48:36
Speaker 1: must be more of a filament here. So they're not
48:39
Speaker 1: actually modeling like the real physics of dark map. They're
48:43
Speaker 1: like saying, if you had a stimulated slime mold and
48:45
Speaker 1: you put in this artificial problem, would it solve that
48:48
Speaker 1: problem effectively? Can you use slime mold computing to figure
48:51
Speaker 1: out where the filaments should be? What are the benefits
48:55
Speaker 1: of trying out sort of a slime mold model versus
48:59
Speaker 1: modeling physics. Is it that having some kind of physics model,
49:03
Speaker 1: we're still asking the questions that we would need to
49:06
Speaker 1: be able to make a physics model. At this point.
49:09
Speaker 1: You can do it with physics as well, but it's
49:11
Speaker 1: difficult because you don't know what the initial conditions are. Like,
49:14
Speaker 1: what we can do with physics is we can say,
49:17
Speaker 1: let's say we had a random universe and let's run
49:19
Speaker 1: a simulation of that and understand how the particles interact
49:22
Speaker 1: and how gravity works. What do you get? And you
49:24
Speaker 1: get a universe with tendrils and galaxies, but you don't
49:27
Speaker 1: get our universe, right, that's a different random universe. So
49:31
Speaker 1: because we don't know what the initial conditions of our
49:33
Speaker 1: universe are, it's hard to run that simulation and so
49:36
Speaker 1: you could like try to run it backwards. So this
49:39
Speaker 1: is just like an alternative approach to say, like, maybe
49:41
Speaker 1: we can find a shortcut, a clever way to solve
49:44
Speaker 1: this problem using ideas from slime molds so that we
49:47
Speaker 1: don't have to figure out how to run the universe backwards. Man,
49:50
Speaker 1: slime molds are so smart. They're teaching us about about physics.
49:54
Speaker 1: It's so interesting and mind blowing to me because with
49:57
Speaker 1: slime molds, when we talk about their intelligent it is
50:01
Speaker 1: not the kind of intelligence of a researcher sitting there
50:04
Speaker 1: programming this, uh, this mimicry of for the slime mold.
50:11
Speaker 1: It's just the the intelligence of a pattern of like
50:15
Speaker 1: individual particles. Let's let's just call one of the unicellular
50:18
Speaker 1: organisms like a particle doing a behavior. What gets even
50:23
Speaker 1: more kind of like Russian nesting dollars. You look at
50:27
Speaker 1: that individual, uh unicellular organism, and it is also basically
50:32
Speaker 1: just a domino effect of particles colliding with each other
50:36
Speaker 1: and interacting so like molecules setting off other molecules. And
50:40
Speaker 1: then that's how that unicellular organism is able to move around.
50:44
Speaker 1: And then you zoom back out, and then many of
50:46
Speaker 1: these unicellular organisms such just it almost makes my eyes
50:51
Speaker 1: crossed just thinking about how many complex like basically little
50:56
Speaker 1: little individual units bonking into each other many many times,
51:01
Speaker 1: and how that can create such incredibly complex and seemingly
51:06
Speaker 1: very intelligent behavior. Yeah, the same way that like a
51:09
Speaker 1: computer can seem intelligence can do complicated things, but at
51:13
Speaker 1: the lowest level, it's just following very simple rules about
51:16
Speaker 1: flipping bits from zeros to ones. And of course we
51:18
Speaker 1: don't know if consciousness could arise from that kind of system,
51:21
Speaker 1: and we also don't know why intelligence and consciousness does
51:24
Speaker 1: arise from our biological system, which in the end, it's
51:27
Speaker 1: just a bunch of neurons zapping each other. So there
51:30
Speaker 1: is really a deep mystery there about the connection between
51:32
Speaker 1: the underlying rules and the emergence of consciousness. But I
51:36
Speaker 1: think it's really cool and you can take advantage of
51:38
Speaker 1: that and say like, well, let's model these systems. Let's
51:41
Speaker 1: figure out what they're doing, and see if we can
51:42
Speaker 1: use that to solve this other problem. And it's awesome
51:45
Speaker 1: to see the connections between problems on the cosmological scale,
51:48
Speaker 1: like the filaments between galaxies and how the universe formed
51:52
Speaker 1: and how this weird GROOPI thing crawls across the forest floor.
51:56
Speaker 1: It really suggests that there are some mathematical connections that
52:00
Speaker 1: they're the problems are similar in some deep way. In
52:03
Speaker 1: the end, the galaxies and the slime molds are both
52:06
Speaker 1: just solving and optimization problem to figure out what's the
52:09
Speaker 1: best way to hang together. I mean that makes me
52:12
Speaker 1: feel kind of more I guess connected to the universe,
52:15
Speaker 1: where you know, it's not the way that these galaxies
52:18
Speaker 1: are behaving, it's it's similar to how something is seemingly simple,
52:23
Speaker 1: as like the slime mold that we can find licking
52:26
Speaker 1: the walls of your local cave or maybe not, maybe
52:29
Speaker 1: don't do that has not been cleared by our legal department.
52:32
Speaker 1: By the way, do not endorse cave looking here at
52:35
Speaker 1: your own risk. I mean there are many they're like
52:39
Speaker 1: splunking in cave looking are both only activities for highly
52:43
Speaker 1: trained individuals, exactly. Professional cave liquors were used for this
52:48
Speaker 1: podcast and folks, But even these slime molds have taught
52:53
Speaker 1: us something about the nature of the universe. These guys
52:56
Speaker 1: ran this simulation and they now have a map of
52:59
Speaker 1: these cosmic filaments between the galaxies. And what they did
53:02
Speaker 1: is then they turned Hubble to one of these locations
53:04
Speaker 1: where they thought, maybe here's a cosmic filament. Our slime
53:07
Speaker 1: mold simulation tells us that should be there, and they
53:10
Speaker 1: were able to see little hints of X rays emissions
53:12
Speaker 1: from what was otherwise deep empty space. So they found
53:16
Speaker 1: new filaments using this simulation. So if they get a
53:19
Speaker 1: Nobel prize, is that going to go to the slime
53:22
Speaker 1: mold or to the researchers who ripped off the slime
53:26
Speaker 1: molds mathematical model. Well, you know, in the great history
53:29
Speaker 1: of professors taking advantage of their students, I think will
53:31
Speaker 1: probably just toss him a few oat flakes and assume
53:33
Speaker 1: that that's enough. But this is a deep mystery in
53:36
Speaker 1: the universe, not just where are the filaments, but where
53:38
Speaker 1: is all the missing stuff? And so understanding where these
53:41
Speaker 1: filaments are might give us a clue is to like,
53:44
Speaker 1: where those missing particles are. Are they really stretching between
53:47
Speaker 1: the galaxies what seems like otherwise empty space. Is there
53:50
Speaker 1: really a third of all the normal matter in the
53:52
Speaker 1: universe in these long bands between galaxies. It would be
53:56
Speaker 1: incredible to discover that a whole third of the pie
53:59
Speaker 1: is really there and what we otherwise thought was deep
54:01
Speaker 1: empty space. I mean, that makes me feel good, warm
54:05
Speaker 1: and fuzzy. It's like we're holding hands with other galaxies.
54:09
Speaker 1: It's not just just cold empty nothingness. We're all just
54:13
Speaker 1: part of the big galactic slime mold. Ah. That's gross,
54:19
Speaker 1: all right, So thanks everybody for joining us for this
54:22
Speaker 1: fun conversation about the structure of the whole universe and
54:25
Speaker 1: how it's creeping along the forest floor of the cosmos,
54:28
Speaker 1: as well as the mysteries of slime molds and how
54:30
Speaker 1: we can take advantage of them to understand the questions
54:33
Speaker 1: of the universe. And thanks Katie for coming along and
54:36
Speaker 1: telling us about your cave looking habits. Yeah. Absolutely, I
54:39
Speaker 1: hope people have an appreciation for even the slimiest, moldiest
54:43
Speaker 1: pritters out there, because maybe they contain the keys to
54:47
Speaker 1: the universe. And it never ceases to amaze me how
54:50
Speaker 1: is even possible for us to understand the universe at
54:52
Speaker 1: any scale, especially at these largest scales, using the tiny
54:56
Speaker 1: little networks encased in our skulls. And so I'm glad
55:00
Speaker 1: that our slime mold brethren have come to help us
55:02
Speaker 1: in that great cosmic detective mystery, the escape Room of
55:06
Speaker 1: the Universe. Is that just your way of saying everyone's
55:09
Speaker 1: got slime for brains? I mean, you ever tasted brains,
55:14
Speaker 1: They're pretty slimey. Alright, Thanks everybody for joining us. Tune
55:20
Speaker 1: in next time. Thanks for listening, and remember that Daniel
55:30
Speaker 1: and Jorge explained. The Universe is a production of I
55:33
Speaker 1: Heart Radio. For more podcast for my Heart Radio, visit
55:36
Speaker 1: the I Heart Radio app, Apple Podcasts, or wherever you
55:40
Speaker 1: listen to your favorite shows.