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How can we see Dark Matter? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Wouldn't it be cool to have, um, like the power
0:12
Speaker 1: to see invisible things, like if you had anti invisibility glasses. Yeah,
0:17
Speaker 1: there's so much of our universe around us that we
0:19
Speaker 1: can't see things that are going on all the time
0:22
Speaker 1: that are invisible to us. It'd be awesome to invent
0:24
Speaker 1: some new technology to reveal that, to peel back that
0:27
Speaker 1: layer of reality and show us all the crazy stuff
0:29
Speaker 1: that's happening. No. Yeah, I would definitely love to see that.
0:33
Speaker 1: Do you have a million dollars to invent invest in
0:35
Speaker 1: my startup? I have a million dollars, but um, maybe
0:39
Speaker 1: not to invest in you, Dadia. Oh, somebody already got
0:42
Speaker 1: to you with that idea, didn't they. Somebody already pitched
0:44
Speaker 1: you Maybe maybe, But yeah, no, I like this idea
0:48
Speaker 1: that there are invisible things out there in the universe
0:51
Speaker 1: that are really important and are maybe determining my fate
0:55
Speaker 1: and the fate of our planets in our solar system
0:57
Speaker 1: and our galaxy. Hi, am Ory, I'm a cartoonist and
1:17
Speaker 1: the creator of PhD comics. Hi I'm Daniel. I'm a
1:21
Speaker 1: particle physicist. I've never created a web comic, but I
1:23
Speaker 1: did co write a book with a web comic. It's
1:26
Speaker 1: called We Have No Idea and it's all about the
1:29
Speaker 1: unknowns in the universe. Oh man, that sounds amazing. I
1:32
Speaker 1: would love to read that. You should, It's fantastic. I
1:35
Speaker 1: did actually read it a couple of times as I
1:38
Speaker 1: helped write it. Did you read your name on the cover?
1:40
Speaker 1: For example? But welcome to our podcast Daniel and Jorge
1:44
Speaker 1: Explain the Universe, a production of I Heart Radio in
1:47
Speaker 1: which we zoom all around the universe and find cool
1:50
Speaker 1: and fascinating and bizarre stuff to blow your mind. But
1:53
Speaker 1: we don't want to explode your mind. We actually want
1:55
Speaker 1: to take that stuff and insert it into your brain.
1:58
Speaker 1: We want to break it down and make it acessible
2:00
Speaker 1: and reassemble it inside your mind. That's right, when it
2:03
Speaker 1: stuff in your mind with as much stuff as we
2:05
Speaker 1: can't without exploding it critical mental density. That's where we're
2:08
Speaker 1: going for in today's show. But yeah, all the cool stuff,
2:10
Speaker 1: all the amazing stuff, all the dark stuff in the universe,
2:13
Speaker 1: all the invisible stuff, all they have visible stuff and
2:16
Speaker 1: everything in between, because there are invisible things out there
2:20
Speaker 1: in the universe, right there are invisible forces and objects
2:23
Speaker 1: and maybe even matter. There definitely is there's a huge
2:26
Speaker 1: amount of stuff going on in the universe that is
2:28
Speaker 1: not directly observable to us, and it's only recently that
2:32
Speaker 1: we've been gone peeling back those layers of invisibility, figuring
2:36
Speaker 1: out ways to subtly detect what's out there that we
2:39
Speaker 1: haven't even noticed, right, And we also try to talk
2:42
Speaker 1: about how scientists are trying to discover these things, how
2:46
Speaker 1: they're trying to peel back that layer and understand what's
2:49
Speaker 1: going on in the invisible universe. That's right. Sometimes I
2:52
Speaker 1: think about it like scientists are are out there inventing
2:56
Speaker 1: new senses, right, Like your senses are your ways of
2:59
Speaker 1: interacting with the world. Old you can see, you can smell,
3:01
Speaker 1: you can touch, all these things help you build up
3:03
Speaker 1: a model of what's outside your body. Right. Well, scientists
3:07
Speaker 1: were like trying to create new contraptions that are basically
3:10
Speaker 1: new senses, things machines that can see things that we
3:14
Speaker 1: our bodies cannot see, and they can translate what they
3:17
Speaker 1: see into something that we can understand. That would be
3:20
Speaker 1: cool if you can build me like a like a
3:22
Speaker 1: radar helmet, like a radar chip, I can implant in
3:25
Speaker 1: my brain and have like bad like abilities or dare
3:28
Speaker 1: devil like abilities exactly. Well, um, if you have a
3:31
Speaker 1: million bucks, you can put that towards the startup I'm
3:34
Speaker 1: going to start after this show inventing the radar helmet.
3:37
Speaker 1: That sounds like an awesome idea. Man, you're really hungering
3:40
Speaker 1: for some hankering for someone for a million bucks here, Daniel.
3:43
Speaker 1: But you know, we we do this kind of thing
3:45
Speaker 1: a lot, right, We extend the power of our senses, right,
3:47
Speaker 1: Think about like what X rays are, right. X rays
3:50
Speaker 1: are these little invisible rays. You can't see them, but
3:53
Speaker 1: we can use them to see inside of stuff, right,
3:56
Speaker 1: to give us to translate what we couldn't see before
3:59
Speaker 1: into what we can see now. Wow, Yeah, you're right,
4:02
Speaker 1: physicists did invent X ray vision. That's right. We literally
4:07
Speaker 1: happen literally right, Yeah, yeah, absolutely, And we do this
4:11
Speaker 1: kind of thing all the time. You know. That's basically
4:13
Speaker 1: what experimental physics is. It's like try to develop a
4:16
Speaker 1: new technology that can discover things that nobody's seen before.
4:20
Speaker 1: Like you know, we've talked on this podcast before about neutrinos.
4:23
Speaker 1: Neutrinos are these weird little particles that are everywhere and
4:26
Speaker 1: they're you know, part of the table of matter as
4:29
Speaker 1: we understand them. But they're very very hard to see
4:31
Speaker 1: because they mostly just fly through stuff. But physicists figured
4:34
Speaker 1: out a way to spot them. It takes billions of
4:37
Speaker 1: neutrinos to fly through your detector before you see one,
4:39
Speaker 1: but we can see them in that way. We discovered
4:41
Speaker 1: that they're there, that the air is full of them.
4:43
Speaker 1: And so today we're going to talk about what scientists
4:46
Speaker 1: are doing to see to actually maybe even touch a
4:51
Speaker 1: very important part of the universe, very big part of
4:54
Speaker 1: the universe, maybe even the biggest part of the universe
4:56
Speaker 1: that's invisible to us. That's right. It makes up most
5:00
Speaker 1: of the matter of the universe, like of the stuff
5:03
Speaker 1: in the universe. It's literally the biggest mystery in the universe.
5:08
Speaker 1: And so today on the program, we'll be talking about
5:15
Speaker 1: how can we see dark matter, how can we interact
5:19
Speaker 1: with it, how can we finally sort of see it
5:22
Speaker 1: up close, touch it maybe and to understand what it is,
5:24
Speaker 1: because right now we have no idea what it is,
5:28
Speaker 1: right Daniel, that's right. We know that it's there, we
5:31
Speaker 1: know that it's stuff. We know it's some kind of
5:33
Speaker 1: matter because it creates gravity. But we don't know what
5:35
Speaker 1: it's made out of. We don't know if it's made
5:37
Speaker 1: out of particles, made at one particle, two particles, seventeen particles,
5:41
Speaker 1: something else that's not a particle. You know, we only
5:44
Speaker 1: have very indirect evidence, very solid, but indirect evidence. It's
5:48
Speaker 1: sort of like you're solving a murder mystery and you
5:51
Speaker 1: have a bunch of circumstantial evidence. You know that Joe
5:54
Speaker 1: Schmo is the guilty party, but you don't have that
5:57
Speaker 1: smoking gun, you don't have the bloody knife or something.
6:00
Speaker 1: You're not going to rest until you really find all
6:02
Speaker 1: the details that really conclusively demonstrate to you what happened
6:05
Speaker 1: on that fateful night. And that's sort of the situation
6:07
Speaker 1: in the case of dark matter. I mean, it could
6:10
Speaker 1: turn out to be that I was a physicist in
6:12
Speaker 1: the cloak room with the wrench, right, I mean, that's
6:15
Speaker 1: what dark matter could be. It could be unicorns, it
6:19
Speaker 1: could be it could have been the engineer in the
6:22
Speaker 1: library right with the bag of dark matter, that's right,
6:25
Speaker 1: trying trying to make things work. Engineers always have altruistic
6:30
Speaker 1: motives in your mind, right, whereas scientists are out there
6:33
Speaker 1: like trying to take over the world. Right, Well, you know,
6:37
Speaker 1: I like to think engineers actually know what they're doing
6:41
Speaker 1: and they're not toying with things they don't understand. You're
6:48
Speaker 1: not trying to create black holes here on Earth, you know, Hey, hey,
6:51
Speaker 1: there's nothing wrong with trying to create black holes on here.
6:53
Speaker 1: And they're tiny, little, cute, very safe black holes. Okay,
6:57
Speaker 1: right right, ped black holes, cozy little black holes, and
7:00
Speaker 1: we got to rebrand them. You know, they sound so dangerous,
7:03
Speaker 1: you know, unicorn black holes. Exactly do you feel like
7:10
Speaker 1: they have a PR problem? Yeah? Exactly, black holes have
7:13
Speaker 1: a PR problem exactly. And for those of you hearing
7:17
Speaker 1: that we are trying to create black holes at the
7:19
Speaker 1: Large Adrian Collider and worrying about it, we have a
7:21
Speaker 1: whole episode dedicated to that, you are in no danger whatsoever. Wait.
7:26
Speaker 1: I just thought of a really nerdy joke. Mm hmmm,
7:31
Speaker 1: Actually black holes have an e PR problem. That's that's
7:38
Speaker 1: a pretty nerdy joke. I agree. Impressive. Thank you. When
7:43
Speaker 1: you have to laugh at your own joke and then
7:45
Speaker 1: rib the other person into into acknowledging it, then that's
7:47
Speaker 1: how you know it was a good joke. Those are
7:50
Speaker 1: Those are the best jokes. Those are the dad jokes. Right,
7:54
Speaker 1: you just made a combination scientist dad joke. It's a
7:56
Speaker 1: whole new subgenre of humor, a dad scientist joke. Well
8:00
Speaker 1: you fortunately, you are as bad scientists, so that hasn't
8:03
Speaker 1: been right. They hit you right in the center. That's right.
8:06
Speaker 1: I am your demographic h Well, that's that's all. Who's
8:11
Speaker 1: listening to this podcast? Right? That's right. Hey, give me
8:14
Speaker 1: a million bucks and I'll do a startup company with
8:16
Speaker 1: dad's scientists jokes. Alright, but only if you pay your
8:20
Speaker 1: podcast partner all of the million dollars. Done and done.
8:25
Speaker 1: All right, we did some business today, all right. So yeah,
8:28
Speaker 1: dark matter, we don't know what it is, and so
8:30
Speaker 1: today we're going to talk a little bit about how
8:33
Speaker 1: we might be able to see it and what scientists
8:35
Speaker 1: are doing to actually see what dark matter is. That's right,
8:38
Speaker 1: and to tease it a little bit. There are three
8:41
Speaker 1: ways that we're looking for dark matter. You can either
8:44
Speaker 1: shake it, break it, or make it. That's also a
8:48
Speaker 1: recipe for cooking a delicious dark matter soufle I feel
8:53
Speaker 1: like that's an informercial all now, and you will receive
8:57
Speaker 1: our special offer for a shake it, break it, and
9:00
Speaker 1: make it and that clever line about shake it, make it,
9:02
Speaker 1: or break it is not something that I came up with.
9:05
Speaker 1: I think the first person to say that was Jonathan
9:07
Speaker 1: Fan He's a dark matter expert at You See Irvine.
9:10
Speaker 1: All right, well let's see how we can shake, break,
9:13
Speaker 1: or make dark matter. But first we were wondering how
9:16
Speaker 1: many people out there think that we could ever see
9:20
Speaker 1: dark matter? Or if we can see dark matter? That's right.
9:23
Speaker 1: So I walked around the campus I You See Irvine
9:25
Speaker 1: and asked folks, hey, do you think we could ever
9:27
Speaker 1: see dark matter? And didn't explain to them what dark
9:30
Speaker 1: matter was or give them much background, and just pop
9:32
Speaker 1: this question on them. And so think about it for
9:34
Speaker 1: a second. If somebody asked you randomly on the street, like, hey,
9:37
Speaker 1: do you think we can ever see dark matter? Think
9:39
Speaker 1: about for a second, how would you answer this question?
9:42
Speaker 1: And would you give that guy a million bucks for
9:44
Speaker 1: his dark matter startup? No? Well, anyways, here's what people
9:50
Speaker 1: had to say. Have you heard of dark matter? Yes,
9:54
Speaker 1: but I don't know what it is? Okay, give any idea?
9:56
Speaker 1: How much see dark matter? Like? How dope? We just
9:58
Speaker 1: discover it. It's like energy electrons. Maybe I'm not really sure,
10:03
Speaker 1: all right, thanks very much. Have you heard of dark matter? Yes?
10:08
Speaker 1: Do you have any idea how we could see or
10:10
Speaker 1: discover dark matter? No? Because it isn't it just a theory?
10:13
Speaker 1: Have you heard of dark matter? Do you know how
10:16
Speaker 1: how might we see dark matter? I don't know if
10:20
Speaker 1: dark I've heard of it, but I can't confidently see
10:23
Speaker 1: about it. Do you know if it's something we could
10:25
Speaker 1: ever see? Like? Can we see or detect dark matter?
10:29
Speaker 1: One day? Probably? I mean I'm not sure now, but
10:31
Speaker 1: I'm confident that one day we'll all find out what
10:35
Speaker 1: it is and discover many things. Okay, I've heard of
10:39
Speaker 1: the term. I'm not exactly sure. I know it's related
10:42
Speaker 1: to like physics in space. Do you know if dark
10:46
Speaker 1: matter something we can ever see? I can we ever
10:49
Speaker 1: be able to see it or detect it? The name
10:53
Speaker 1: implies that we can't, but I'm sure there are methods too,
10:58
Speaker 1: I mean through like radiation, probably can detect if it's there,
11:02
Speaker 1: but I don't know. Pre too visible to see. All right,
11:05
Speaker 1: a little bit of optimism. Some people have never heard
11:08
Speaker 1: of it, Yeah, some people were a little skeptical. I
11:10
Speaker 1: like the well, it's just a theory, like I could
11:14
Speaker 1: have gotten into a whole discussion there about what is
11:16
Speaker 1: a scientific theory, evolution is a theory, what does theory mean?
11:19
Speaker 1: But I just world have nodded and moved on. There
11:21
Speaker 1: was one interesting answer here, uh that said that, UM,
11:25
Speaker 1: that the answer is no because the name of it
11:29
Speaker 1: implies that we can't see it. That's kind of a
11:31
Speaker 1: pretty metaphysical answer, right, like, if we can't see it
11:35
Speaker 1: one day, do we need to change the name of it? Oh?
11:38
Speaker 1: I see, Well, I think that's a little bit more
11:40
Speaker 1: thought than this person I had given it. Um. I
11:43
Speaker 1: think they were not sure what dark matter was and
11:46
Speaker 1: just trying to sort of grasping for clues about how
11:48
Speaker 1: to answer this question based on the limited information in
11:51
Speaker 1: the question. And uh, I think that's where they were going.
11:54
Speaker 1: But I like, I like the idea that if we
11:56
Speaker 1: see dark matter, we can't call it dark anymore. We
11:58
Speaker 1: have to rename it. And probably you're angling to be
12:01
Speaker 1: on that committee to rename it, because I know you
12:03
Speaker 1: have opinions about how physicists have named things. It's not
12:06
Speaker 1: that I'm angling, I just I just feel like anyone
12:08
Speaker 1: could do a better job. Put that on your application
12:13
Speaker 1: to be on the committee. Man, you guys are terrible.
12:16
Speaker 1: Anybody could do a better job than you. Yeah, for sure,
12:19
Speaker 1: they should put kids in charge of naming things. You know,
12:22
Speaker 1: then we'd be called squishy rainbow matter. Yeah, there you go.
12:25
Speaker 1: It would make a lot more sense and be harder
12:29
Speaker 1: to write grand proposal saying please give us money to
12:31
Speaker 1: see squishy rainbow particles. Right, unless it's also children reviewing
12:35
Speaker 1: the proposals. Sometimes I think it is children reviewing the
12:39
Speaker 1: proposals based on the referee reports. So Dan, it remind
12:42
Speaker 1: us what dark matter is, right, So we don't know
12:45
Speaker 1: what dark matter is, but we know that there's something
12:48
Speaker 1: out there. We know that there's a bunch more stuff
12:51
Speaker 1: in the universe than we can see. And we know
12:54
Speaker 1: this in a few ways, but all of them just
12:56
Speaker 1: use gravity. Gravity is our clue that tells us that
12:59
Speaker 1: there's something us out there that has mass, because remember
13:02
Speaker 1: mass is what creates gravity, a mass and energy. And
13:06
Speaker 1: we have a few clues, like we looked at galaxies
13:09
Speaker 1: and we see that galaxies are spinning really really fast,
13:12
Speaker 1: and there doesn't seem to be enough gravity inside those
13:15
Speaker 1: galaxies just from the stuff we can see, the stars
13:18
Speaker 1: and the dust and stuff to hold those galaxies together.
13:21
Speaker 1: So based on how fast they're spinning, the galaxies should
13:24
Speaker 1: be tearing themselves apart, the stars should be thrown off
13:26
Speaker 1: into interstellar space, but they're not. So people suggested this idea.
13:31
Speaker 1: Maybe there's some invisible matter in there that's creating this
13:34
Speaker 1: gravity to hold the galaxies together. And that's the key.
13:37
Speaker 1: It's invisible. We can't see it, hence the name dark,
13:40
Speaker 1: but it creates the missing gravity. We need to explain
13:43
Speaker 1: how these galaxies are spinning. So they called it matter
13:45
Speaker 1: because it gives gravity. So it's like we we can
13:48
Speaker 1: feel it, but we just can't see it. Like we
13:51
Speaker 1: can see it affecting the orbits of things around it,
13:54
Speaker 1: and we can see it affecting how light moves around
13:57
Speaker 1: it and through it, but we can actually see something
14:01
Speaker 1: there or detect something there through light. That's right. We
14:05
Speaker 1: can't use light to detective because it doesn't seem to
14:07
Speaker 1: interact with light at all. It's invisible, you know, the way,
14:10
Speaker 1: like the air is. You can tell the air is
14:12
Speaker 1: there because it pushes against you, but you can't see it. Right,
14:15
Speaker 1: you'd love to be able to see the air. Imagine
14:17
Speaker 1: you had like glasses that you could see different air
14:19
Speaker 1: currents and stuff like that. The world would look like
14:21
Speaker 1: a crazy place. But we can see it only through gravity.
14:25
Speaker 1: You can tell that it's there through gravity. And the
14:28
Speaker 1: reason that's the problem. It's pull. Yes, we can feel
14:31
Speaker 1: it's pull. And you might think, isn't that enough, Like,
14:33
Speaker 1: I mean, you're getting greedy, Like you can already tell
14:36
Speaker 1: the dark matter is there, why do you need to
14:37
Speaker 1: see it? The thing is that gravity is really really weak.
14:40
Speaker 1: It's the weakest force by huge amount, by millions and
14:44
Speaker 1: millions and millions, and so we can only use gravity
14:47
Speaker 1: to see dark matter when there's a huge amount of it,
14:50
Speaker 1: like galaxy sized blobs of it. So that tells us
14:53
Speaker 1: that it's there, but it doesn't really tell us what's
14:56
Speaker 1: going on where the dark matter is, to see any
14:58
Speaker 1: detail in it, to see this isn't made out of
15:01
Speaker 1: particles or is it made out of something else? Really weird.
15:03
Speaker 1: It's like it's enough to know that it's there and
15:05
Speaker 1: roughly where it is, but nothing else about it. And
15:08
Speaker 1: that's tantalizing, you know, because we want to know what
15:10
Speaker 1: this is made out of and how it works and
15:12
Speaker 1: does it interact and is there complicated stuff going on?
15:15
Speaker 1: But we can't. Right, we're blind because gravity is so weak, right,
15:19
Speaker 1: And and so it doesn't reflect light, like if I
15:21
Speaker 1: shine a light into it, the light it is going
15:23
Speaker 1: to go through, and it doesn't emit any light, Like,
15:27
Speaker 1: it doesn't glow or it doesn't give off its own
15:29
Speaker 1: energy that we can see. And so that's what makes
15:32
Speaker 1: it invisible. That's right. Stars give off lights so we
15:36
Speaker 1: can see them. Planets reflect lights so we can see them.
15:39
Speaker 1: Dark matter doesn't either. It doesn't glow and it doesn't
15:41
Speaker 1: reflect light. Yeah, it's totally invisible to loost. It's like
15:45
Speaker 1: a ghosts ghost, Yeah, exactly. I like how sometimes you
15:49
Speaker 1: say that it should have just been called invisible matter,
15:51
Speaker 1: not dark matter. Yeah. I think probably there was a
15:53
Speaker 1: meeting some somewhere somebody said let's call it invisible matter,
15:56
Speaker 1: and then no, dark matter sounds cooler, and I think
15:59
Speaker 1: dark matter does sound cooler. Honestly, dark implies something mysterious,
16:03
Speaker 1: write something maybe a little sinister. One of my favorite
16:06
Speaker 1: questions I get when we give public lectures is somebody
16:09
Speaker 1: invariably asks, is dark matter like bad matter? Like is
16:13
Speaker 1: it dangerous? You know, because it's an error of like
16:16
Speaker 1: you know, sinisterns or what's the word cynicism sinisterism? Do
16:22
Speaker 1: just call it evil matters? Well, I mean, who wouldn't
16:26
Speaker 1: fund that project? Yeah, it's it's like the dark side
16:29
Speaker 1: of the force, right, you know, it's just there, you go,
16:34
Speaker 1: there's my million bucks boom, just like, Hey, there's evil
16:37
Speaker 1: matter out there. We need to track it down. That's
16:41
Speaker 1: something the current administration would probably go for you. Yeah, alright,
16:46
Speaker 1: So that's what that's what dark matter is. Uh, it's
16:49
Speaker 1: some stuff out there in the universe. There's a lot
16:51
Speaker 1: of it. There's a there's like five times more of
16:54
Speaker 1: it than regular matter. But we can't see it through
16:57
Speaker 1: light or touch it because how we touch things is
16:59
Speaker 1: the through electromagnetic forces, right, that's right. If you want
17:03
Speaker 1: to push on the wall that's next to you, for example,
17:06
Speaker 1: why doesn't your hand go through the wall. It's because
17:08
Speaker 1: your hand is a bunch of molecules, and those molecules
17:11
Speaker 1: are tied together with chemical bonds, which are mostly bonds
17:15
Speaker 1: from electrons, and so though that uses electromagnetism. So your
17:19
Speaker 1: hand is like a like a chain link fence, and
17:22
Speaker 1: the walls like a chain link fence, and those links
17:24
Speaker 1: press against each other. So electromagnetism is the dominant force
17:27
Speaker 1: and how you see things and how you feel things
17:29
Speaker 1: in dark matter just doesn't feel it at all. So
17:32
Speaker 1: it seems kind of unlikely that will ever be able
17:35
Speaker 1: to touch it or see it or know what it
17:38
Speaker 1: is with any kind of resolution. And so let's get
17:40
Speaker 1: into this idea of shaking it, breaking it, and making it.
17:44
Speaker 1: But first let's take a quick break, Okay, Daniels. So
17:59
Speaker 1: dark matter, it doesn't give off light or reflect light,
18:03
Speaker 1: or it doesn't even care about light, and just light
18:05
Speaker 1: just goes through it or magnets. Hey, you don't know that.
18:09
Speaker 1: Maybe it's like feeling left out. It's like, hey, this
18:12
Speaker 1: is this LFE part of the universe and all this
18:14
Speaker 1: fun stuff is happening, and we're stuck over here in
18:16
Speaker 1: the dark corner. Maybe we should call it sad matter
18:18
Speaker 1: then depressed matter exactly. But yeah, so but you know,
18:23
Speaker 1: and generally you can't touch up with light, you can't
18:26
Speaker 1: touch it with a magnet, you can't touch it with
18:27
Speaker 1: your finger. Um, but we know it's there because we
18:30
Speaker 1: feel it's gravitational pool. So you're saying that that that
18:34
Speaker 1: gravitational poll is not enough to really study it, to
18:38
Speaker 1: really kind of kind of like run it through your
18:41
Speaker 1: fingers and study what it is and what it's made
18:43
Speaker 1: out of. That's right. The goal is to get a
18:45
Speaker 1: finer grain sense of where it is, like where on
18:48
Speaker 1: Earth is the dark matter? Is it just a big
18:50
Speaker 1: diffuse blob. Is it clumped up somewhere? Is it all
18:53
Speaker 1: gathered in the sun. You know, we'd like to be
18:55
Speaker 1: able to see it much more, a much finer grain resolution,
18:59
Speaker 1: which requires interacting with it more powerfully than gravity can do. Um,
19:04
Speaker 1: that's one thing. And the other thing is we'd like
19:05
Speaker 1: to know what it's made out of, right, like is
19:07
Speaker 1: it made out of particles, it made multiple particles or
19:09
Speaker 1: something else totally different, And that definitely requires seeing it
19:12
Speaker 1: more up close and interacting with it. And so currently
19:16
Speaker 1: the only thing we can do is gravity. And you know,
19:18
Speaker 1: let's start off pessimistically. It might be that dark matter
19:22
Speaker 1: only feels gravity and that's the only force that ever
19:24
Speaker 1: will feel, and that seeing it or touching it or
19:27
Speaker 1: whatever is totally hopeless. But we have no concrete evidence
19:32
Speaker 1: that it has to feel another force. We have some
19:34
Speaker 1: indirect clues from the way things happened in the early universe,
19:37
Speaker 1: but nothing really solid. Well, here's a question then, I mean,
19:41
Speaker 1: we know that dark matter doesn't feel light or electromagnetic forces,
19:46
Speaker 1: and we know it doesn't feel weak forces or strong forces.
19:51
Speaker 1: I know it's because I listened to our podcast episode
19:53
Speaker 1: about dark matter. Um, but um, how do we know
19:57
Speaker 1: it doesn't feel maybe some other forces, some other year
20:00
Speaker 1: to undiscovered forces in the universe. Yes, in fact, we
20:03
Speaker 1: are hoping that it does, right, We are arresting the
20:06
Speaker 1: entire This entire field of searching for dark matter rests
20:08
Speaker 1: on the hope that there is some new kind of force,
20:11
Speaker 1: some way that dark matter interacts with itself and with
20:14
Speaker 1: our kind of matter. So if it only interacts with
20:17
Speaker 1: via gravity, then we're kind of sunk. All we can
20:19
Speaker 1: never do is do observational astronomy and see galaxy sized blobs.
20:23
Speaker 1: But if there is some new force we haven't discovered yet,
20:27
Speaker 1: then maybe it can mediate the interactions between normal particles
20:31
Speaker 1: like electrons and corks and these dark matter particles. So
20:34
Speaker 1: that would be awesome because you could make two discoveries
20:37
Speaker 1: at once. You discover some new force which is huge,
20:40
Speaker 1: and you discover that that new force interacts with dark
20:43
Speaker 1: matter particles, so you discover a new force and a
20:45
Speaker 1: new particle and the same day, like two discoveries for
20:48
Speaker 1: the price of one. Is that possible though? Is it
20:51
Speaker 1: possible that there is another force that we haven't noticed? Oh? Absolutely, absolutely,
20:56
Speaker 1: it's possible. Yeah. I mean we've only studied a tiny
21:00
Speaker 1: fraction of the universe and the interactions between those particles,
21:03
Speaker 1: So it's certainly possible that there are other kinds of
21:05
Speaker 1: interactions that we haven't noticed because the particles were familiar
21:08
Speaker 1: with don't interact that way. Oh I see so, but
21:11
Speaker 1: so then we wouldn't be able to measure this force then,
21:15
Speaker 1: exactly so. But it could also be that this force
21:18
Speaker 1: is just very very weak, that it's not very powerful,
21:21
Speaker 1: and so it's hard to detect. But if you have
21:23
Speaker 1: enough clever physicists, they can build a device to suss
21:26
Speaker 1: it out and to notice those tiny little hints that
21:29
Speaker 1: give us the clues that it's there, just like we
21:31
Speaker 1: found neutrinos. Neutrinos are very very difficult to interact with.
21:34
Speaker 1: They only feel the weak nuclear force, but we were
21:37
Speaker 1: able to build detectors that can spot them, so we
21:40
Speaker 1: know that they are there. In the same way, if
21:43
Speaker 1: there's another force that dark matter feels where we're gonna
21:47
Speaker 1: talk about in a minute. Are all the ways that
21:48
Speaker 1: we're trying to reveal dark matters interaction with normal matter
21:52
Speaker 1: through that new force. But if it only feels gravity,
21:55
Speaker 1: don't we have some amazing gravitational wave detectors now, couldn't
21:59
Speaker 1: that may be help us. We do have amazing gravitational
22:02
Speaker 1: wave detectors, but as far as I understand, they don't
22:05
Speaker 1: give us much insight into where the dark matter is
22:08
Speaker 1: because gravitational waves come from like huge accelerating masses like
22:12
Speaker 1: black holes and neutron stars circling each other and eating
22:15
Speaker 1: each other. Dark matter, as far as we know, doesn't
22:18
Speaker 1: do that, and so it doesn't create gravitational waves as
22:21
Speaker 1: far as I know. But you know, there could be
22:23
Speaker 1: black holes made of dark matter. I guess that are
22:26
Speaker 1: doing that, but it wouldn't necessarily give us insight into
22:28
Speaker 1: the dark matter itself. But wait, would those be dark
22:31
Speaker 1: black holes or black dark holes? I don't know. Um,
22:36
Speaker 1: that's your responsibility since you're being nominated to the Physics
22:39
Speaker 1: Naming Committee, But I'm pretty sure that every black hole
22:42
Speaker 1: has to have some dark matter in it, because remember,
22:44
Speaker 1: eight of the matter in the universe is dark matter.
22:46
Speaker 1: So if you're a black hole, you're just indiscriminately sucking
22:49
Speaker 1: up matter and you're definitely gonna hoover up some dark matter.
22:57
Speaker 1: So it seems like a pretty hard problem. And so
22:59
Speaker 1: break it down for us den. What are some of
23:01
Speaker 1: the different options for studying dark matter? Alright? So number
23:05
Speaker 1: one is shake it. And the idea here is, let's
23:09
Speaker 1: build a really big tank a very quiet liquid. By quiet,
23:13
Speaker 1: we mean liquid that doesn't interact very much, mostly just
23:16
Speaker 1: sits there. And we put this tank really far underground,
23:20
Speaker 1: so the cosmic rays and other particles from space don't
23:23
Speaker 1: interact with it very much. And then you just wait.
23:25
Speaker 1: You wait for one of those particles to shake. The
23:28
Speaker 1: idea is that maybe a dark matter particle, which should
23:31
Speaker 1: have no trouble penetrating through the ground and getting all
23:33
Speaker 1: the way underground into your your vat of liquid, will
23:37
Speaker 1: bump using this new force, will bump into one of
23:39
Speaker 1: these molecules and shake it a little bit. And when
23:42
Speaker 1: you spot that, you can say, ah, maybe that was
23:44
Speaker 1: dark matter. Oh I see, so you're not shaking the
23:47
Speaker 1: dark matter. You're just waiting for dark matter to shake
23:49
Speaker 1: something else. That's right. We're hoping that dark matter flies
23:52
Speaker 1: down and then occasionally bumps into one of these it's
23:55
Speaker 1: usually liquid xenon atoms, and then we can see that
23:58
Speaker 1: atom shaking, so we you know that that's where the
24:02
Speaker 1: force comes in. Gravity isn't enough for that to happen.
24:05
Speaker 1: But if dark matter has this new force, it could
24:07
Speaker 1: give a little bump to one of these xenon atoms,
24:10
Speaker 1: and by seeing them get bumped, then we could deduce
24:12
Speaker 1: that maybe it's dark matter. So the theory is that
24:15
Speaker 1: maybe dark matter feels does feel more than just gravity,
24:19
Speaker 1: like maybe it feels us some kind of other force.
24:22
Speaker 1: But it's so weak that you really would have to
24:25
Speaker 1: isolate everything else just to maybe every once in a
24:28
Speaker 1: while feel that force from dark matter. It's like you're
24:32
Speaker 1: listening for the tiniest little whisper. Right, you don't want
24:35
Speaker 1: to do that in a crowded stadium or in a bar.
24:38
Speaker 1: You want to go to a place where there's nothing
24:40
Speaker 1: going on, so you can really crank up they gain
24:43
Speaker 1: on your on your microphone and listen for that little whisper.
24:46
Speaker 1: So we go deep, deep underground to look for these
24:49
Speaker 1: little particle whispers because they're probably drowned out. I mean,
24:52
Speaker 1: if dark matter is around, then it may be interacting
24:55
Speaker 1: with us all the time, right, giving little shakes, But
24:58
Speaker 1: you can't tell because there's particles everywhere giving shakes, but
25:01
Speaker 1: deep down underground, most of those particles are filtered out.
25:04
Speaker 1: And you put a really quiet liquid there, and then
25:06
Speaker 1: you hope that dark matter hits it, and you know,
25:09
Speaker 1: you might be thinking, well, how can you tell it
25:11
Speaker 1: was dark matter not something else? Right? What they've come
25:14
Speaker 1: up with really clever ways to distinguish between dark matter
25:17
Speaker 1: hitting it and like a gamma ray hitting it or
25:19
Speaker 1: nuclear radioactive decay hitting it, because dark matter is probably
25:25
Speaker 1: heavier than like electrons, and and because different kind of
25:29
Speaker 1: recoil than a gamma ray. So they have all these
25:31
Speaker 1: really clever details about ways to see it, and that
25:35
Speaker 1: make it more likely to tell if it's dark matter
25:37
Speaker 1: or not. But you can never be for sure. You
25:39
Speaker 1: can never be sure that one of these wiggles is
25:43
Speaker 1: exactly dark matter. Okay, so that's pretty good. Is that
25:45
Speaker 1: an actual like physics position, like particle whisperer, But it
25:50
Speaker 1: should be. It should be again, when you're on the
25:52
Speaker 1: naming committee, you can rename these titles anything you like.
25:55
Speaker 1: You know, throw a professor and come in with particle whisper.
25:59
Speaker 1: But the key is the key is that I don't
26:01
Speaker 1: think anybody would really conclusively accept the discovery of dark
26:05
Speaker 1: matter just from that kind of experiment. And that's why
26:07
Speaker 1: we have three prongs of this search. We have um,
26:10
Speaker 1: shake it, break it, and make it, because if dark
26:13
Speaker 1: matter does exist and it does feel this new force,
26:16
Speaker 1: we would expect to see it in all three prongs,
26:18
Speaker 1: and that would really be more conclusive. Why don't you
26:20
Speaker 1: think people would not believe it? It's a hard experiment
26:23
Speaker 1: to do, and the kind of signal we're looking for
26:27
Speaker 1: is like one or two shakes over a year of running.
26:32
Speaker 1: And then you have to really have a lot of
26:33
Speaker 1: confidence that these folks know what other kind of things
26:36
Speaker 1: might shake those molecules at the same level, Um, that
26:39
Speaker 1: they've really done everything carefully. You know, it's not as
26:43
Speaker 1: like direct as you'd like. You'd like to like hold
26:46
Speaker 1: the dark matter particle and say here it is, everybody,
26:48
Speaker 1: come and look at it. We found it, right, But
26:50
Speaker 1: instead you're you're noticing it bumps somebody, and that's still
26:54
Speaker 1: a bit indirect. I mean, it's more direct than gravity
26:56
Speaker 1: because you're talking about the interaction with a particle, but
26:58
Speaker 1: you're not left with it. You haven't to create intergator
27:00
Speaker 1: been able to study it. Well, I remember our conversation
27:03
Speaker 1: about the sky being blue. That you know, things have
27:06
Speaker 1: to be kind of around the same size or the
27:09
Speaker 1: same frequency for them to interact. Is it possible that
27:11
Speaker 1: maybe dark matter is just like at a different frequency
27:15
Speaker 1: or wavelength. It's certainly is possible, right, It's possible that
27:19
Speaker 1: dark matter fields forces and those forces don't interact with
27:21
Speaker 1: our matter at all. Right, it's certainly possible. Um. And
27:25
Speaker 1: these detectors are sensitive to dark matter of certain masses, right,
27:29
Speaker 1: usually between like a few giga electron volts and a
27:32
Speaker 1: hundred giga electron bolts. And they're sensitive to those masses
27:36
Speaker 1: because those are the masses that are going to make
27:38
Speaker 1: the particles shake the way they're expecting. If the masses
27:41
Speaker 1: are much much smaller or much much heavier than the
27:43
Speaker 1: shake is going to be different and they might not
27:45
Speaker 1: spot it. So yeah, these have windows where they can
27:48
Speaker 1: see it. And again that's why we have different approaches,
27:51
Speaker 1: so we can try to cover all the blind spots. Okay,
27:53
Speaker 1: so that's option number one in our infomercial offering is
27:57
Speaker 1: listening to dark matter whispers at the dark whispers that's right,
28:02
Speaker 1: And see if it maybe bumps a particle in a really,
28:05
Speaker 1: really really quiet environment. But that one is a little
28:08
Speaker 1: suspicious because it's so hard, and but you're saying there's
28:10
Speaker 1: a second option, which is to break it, break dark matter.
28:13
Speaker 1: That's right. Um, if you imagine this the interaction we
28:17
Speaker 1: talked about a moment ago shaking it, that's one dark
28:19
Speaker 1: matter particle comes in and a normal matter particle comes in,
28:22
Speaker 1: like xenon, and then both those come out. Xenon comes
28:26
Speaker 1: out and dark batter comes out. Can sort of rotate
28:28
Speaker 1: that ninety degrees in your head and say, well, if
28:30
Speaker 1: that can happen, then maybe it's possible for two dark
28:33
Speaker 1: matter particles to bump into each other, annihilate using the
28:38
Speaker 1: same force, and turn into normal matter particles quarks for example,
28:42
Speaker 1: which is what makes a zenon. And so it's the
28:45
Speaker 1: same interaction, right, it's dark matter interacting with quarks um,
28:50
Speaker 1: but instead of dark matter bouncing off of corks, it's
28:52
Speaker 1: dark matter annihilates itself and turns into corks. Oh, because
28:58
Speaker 1: dark matter, if it's in our universe, it's stuff. And
29:03
Speaker 1: if it's stuff, then it can turn into energy, which
29:07
Speaker 1: can then turn into other things. That's right, And only
29:11
Speaker 1: if there's this particular force, this force that can that
29:14
Speaker 1: can touch normal matter and can touch dark matter, then
29:18
Speaker 1: dark matter can annihilate. It turns into the particle that
29:21
Speaker 1: mediates this new force, and that particle that mediates this
29:24
Speaker 1: new force can also touch normal matter, right, and so
29:28
Speaker 1: we can turn into normal matter. That's the idea. It
29:31
Speaker 1: would have to be a new kind of force, or
29:32
Speaker 1: it could like the weak force or one of these
29:34
Speaker 1: forces do that. We thought for a while the weak
29:37
Speaker 1: force might be able to do that, and maybe dark
29:38
Speaker 1: matter felt the weak force like neutrinos, but we pretty
29:41
Speaker 1: much ruled that out because if that had happened, we
29:43
Speaker 1: would have seen it already. Our detectors are powerful enough
29:46
Speaker 1: to see dark matter interacting via the weak force, and
29:48
Speaker 1: it hasn't. So it have to be a new force.
29:52
Speaker 1: But you're saying, but we don't really know what dark
29:53
Speaker 1: matter is, So how can we be so confident that
29:56
Speaker 1: we haven't seen it this way? We don't know what
29:58
Speaker 1: dark matter is, and so we are not confident in
30:01
Speaker 1: basically anything. But all we can do is what we
30:03
Speaker 1: can do, and we can say, well, what if dark
30:06
Speaker 1: matter is a particle, and what if it interacts with
30:09
Speaker 1: normal matter? What would that look like. Okay, let's go
30:11
Speaker 1: look for that and if we find it, awesome. If
30:14
Speaker 1: we don't find it, then there's a lot of things
30:17
Speaker 1: that we might wonder about, like, well, maybe it's not
30:19
Speaker 1: a particle, or maybe it doesn't interact with via this
30:21
Speaker 1: new force, or maybe we built this thing wrong. Right,
30:23
Speaker 1: So negative results are less powerful than positive results, for sure,
30:27
Speaker 1: But you can only do what you can do right.
30:29
Speaker 1: And in science we do this a lot. We say,
30:31
Speaker 1: we don't know how to solve this problem. Let's start
30:33
Speaker 1: simple and see if that works. Let's imagine it's a
30:35
Speaker 1: unicorn and see if we see any rainbows. That's right.
30:38
Speaker 1: And so you might be wondering like, well, how do
30:40
Speaker 1: you make dark matter collide into other dark matter? And
30:42
Speaker 1: the way you do it is that you just look
30:44
Speaker 1: for places where there's a lot of dark matter. And
30:47
Speaker 1: we think that dark matters clumped at the center of
30:49
Speaker 1: the galaxy, like close to that black hole that's the
30:52
Speaker 1: biggest blob of dark matter. So what we do is
30:54
Speaker 1: we point our space telescopes at the center of the
30:57
Speaker 1: galaxy and we wait and we hope to see like
31:01
Speaker 1: a flash of light from the center of the galaxy
31:04
Speaker 1: that's of a particular energy that would tell us that
31:07
Speaker 1: dark matter collided and created normal matter. It's a really
31:11
Speaker 1: hard thing to do. Yeah, it seems like a really
31:14
Speaker 1: wishful thinking, or you know, like you're reaching a little bit.
31:18
Speaker 1: It is, but you know, there was a moment when
31:19
Speaker 1: we thought we saw a signal a few years ago.
31:22
Speaker 1: We had the data from this telescope. And if dark
31:25
Speaker 1: matter exists and it can do this and it happens,
31:29
Speaker 1: then you would expect that all the particles that come
31:32
Speaker 1: from the center of the galaxy would have a particular energy,
31:35
Speaker 1: and that energy would tell you what the mass of
31:36
Speaker 1: the particle was. So you'll be looking for like a
31:38
Speaker 1: peak over a spectrum. And there was a guy in
31:41
Speaker 1: the Germany who looked at the data and he saw
31:43
Speaker 1: this big peak in the spectrum and every thought, oh
31:45
Speaker 1: my gosh, maybe he discovered dark matter. Then it turned
31:48
Speaker 1: out no, really, so um it would it would happen
31:54
Speaker 1: in a big flash that's brightened us for us to see.
31:57
Speaker 1: It's not one big flash. It's a slow accumulu lation
32:00
Speaker 1: of data. It's like great build up years and years
32:03
Speaker 1: of information and then maybe you see a bunch of
32:06
Speaker 1: of um. You see a bunch of these things all
32:09
Speaker 1: the same energy, and that tells you that maybe there's
32:11
Speaker 1: something else going on here, some process that's happening in
32:14
Speaker 1: the center of the galaxy that's producing these particles at
32:16
Speaker 1: all the same energy, and that gives you a clue
32:18
Speaker 1: as to what the dark matter is. And again, on
32:21
Speaker 1: its own, not that convincing. But if you see that
32:24
Speaker 1: and you see something in these underground detectors and the
32:27
Speaker 1: two are consistent, you're like, oh, look, maybe these two
32:30
Speaker 1: things are telling us the same story from a different
32:32
Speaker 1: point of view. Then you start to build up a
32:34
Speaker 1: credible story. All right. But then and now there's even
32:38
Speaker 1: um a third option to study dark matter, right, that's right,
32:42
Speaker 1: And this is my favorite because of the one that
32:44
Speaker 1: I personally work on, and that's making dark matter. I
32:47
Speaker 1: feel like, if we're going to believe the dark matters
32:49
Speaker 1: of particle, we got to be able to create it.
32:51
Speaker 1: We've got to be able to like make it in
32:53
Speaker 1: the lab and play with it and study it. So
32:56
Speaker 1: that's what we're trying to do at the large hair
32:58
Speaker 1: Dum Collier. You laugh, You think that's ridiculous. Wow. We
33:02
Speaker 1: just talked a little bit earlier about scientists making things
33:05
Speaker 1: and playing with things that they don't fully understand. Yeah, exactly,
33:09
Speaker 1: that's how we understand them. Right, you know, what is
33:11
Speaker 1: this thing? I don't know? Let's make a pile of
33:13
Speaker 1: it and poke it and see what happens. That's not
33:15
Speaker 1: a grand plan to take over the world. It's not
33:17
Speaker 1: like here, I'm going to become the dictator of the
33:19
Speaker 1: Earth by making dark matter. Right, dark matter is not dangerous.
33:23
Speaker 1: It's like it's even difficulty to spot, to to interact with. Right,
33:27
Speaker 1: it's not going to hurt anybody. We just like want
33:29
Speaker 1: to create some of us so we can see what
33:30
Speaker 1: it's like. Is that so wrong? Uh? Well, I'll let
33:38
Speaker 1: you know, of you guys the story of the Earth.
33:40
Speaker 1: I'll let you know if that was a good idea
33:41
Speaker 1: or not. Drop me a line. But then on my tombstone?
33:44
Speaker 1: Was that so wrong? In your tombstone? Inside the dark
33:48
Speaker 1: matter black hole? Okay, that sounds good. Dark matter black holes.
33:53
Speaker 1: There's a start of idea. One million bucks. Please, Well,
33:55
Speaker 1: this is a perfect point to take a break. You're
34:11
Speaker 1: saying another way to study dark matter is to make
34:14
Speaker 1: it to like created out of nothing. Yes, not out
34:18
Speaker 1: of nothing. So imagine think about the process we just
34:21
Speaker 1: talked about in the Galactic Center. We're talking about dark
34:24
Speaker 1: matter annihilating it to some particle and that particle turning
34:27
Speaker 1: into quarks. Well, if that can happen, then the reverse
34:30
Speaker 1: can happen. That is, quarks should be able to annihilate
34:33
Speaker 1: turn into some new force particle, and that new force
34:36
Speaker 1: particles should be able to turn into dark matter. So
34:39
Speaker 1: we should be able to smash corks together and create
34:42
Speaker 1: dark matter. And that's coincidentally exactly what we're doing at
34:45
Speaker 1: the Large Hadron Collider. We smash quarks in the form
34:48
Speaker 1: of bags that we call protons together it's super high speeds,
34:52
Speaker 1: and try to create new kinds of matter. But again,
34:54
Speaker 1: that assumes that you have this magical force that helps
34:59
Speaker 1: you go between the two worlds kind of right, Yes, exactly,
35:02
Speaker 1: we have to assume that it's it's there to look
35:04
Speaker 1: for it, right. It's like you're saying, like, well, you
35:07
Speaker 1: went hunting for unicorns in the forest, and you're assuming
35:09
Speaker 1: the unicorns exist, Well, you know, we're out there looking
35:12
Speaker 1: for them, like we'll see. Right. It is that kind
35:16
Speaker 1: of similar, right, Like yeah, yeah, sure. But you know,
35:20
Speaker 1: if you go out looking for unicorns and you find
35:22
Speaker 1: something else crazy instead, you still call it a success. Right,
35:25
Speaker 1: But you have to have something to look for, and
35:27
Speaker 1: this in particular, like you know, we believe dark matter
35:30
Speaker 1: is there. Of all the crazy things we look for
35:32
Speaker 1: at the Large Header and Collider, most of them we
35:34
Speaker 1: have no clue that exists. Supersymmetry and large extra dimensions
35:38
Speaker 1: and all this other crazy stuff. We have no real
35:40
Speaker 1: clue that it's even real. Dark matter, we know is
35:43
Speaker 1: a thing. It's out there. It's part of the universe. Man,
35:46
Speaker 1: It's like it's an important element in the matter pie.
35:49
Speaker 1: So at the Large Hadron Collider and we smash particles together,
35:52
Speaker 1: we make everything that can be made. So if dark
35:56
Speaker 1: matter exists and it can be made, then eventually we'll
35:59
Speaker 1: make it, and we to be able to find it
36:01
Speaker 1: in the remnants of some of those collisions. Right. And
36:03
Speaker 1: the interesting thing is that it's not like you make
36:05
Speaker 1: it and then you hold it in your hand and say,
36:07
Speaker 1: hey see I made it. It's more like you made it.
36:10
Speaker 1: That is my particular fantasy. But you're right, well, technically
36:14
Speaker 1: you do have some dark matter in your hand already. Right,
36:17
Speaker 1: that's right. But you can't hold it because it passes
36:19
Speaker 1: through you, because it doesn't interact with you. But you're right,
36:21
Speaker 1: go ahead. You can't just make it and hold it. Yeah, yeah,
36:24
Speaker 1: I think the the idea is that you make it
36:27
Speaker 1: and you um, and you know that you made it
36:30
Speaker 1: because some energy disappeared and you can't account for it. Exactly.
36:33
Speaker 1: The problem with making dark matter is that we can't
36:35
Speaker 1: and then see the dark matter. It's like, hey, look,
36:38
Speaker 1: I here's my Science Fair project. I made an invisible man.
36:41
Speaker 1: You can't touch. Where is he? I don't know. Um,
36:44
Speaker 1: it's not that convinced. I made your lasagna, but it
36:46
Speaker 1: disappeared after I made it. But hey, the effort is
36:49
Speaker 1: what counts, right, honey, here's your invisible Mother's Day present. Um, exactly,
36:54
Speaker 1: I didn't forget. It's just invisible. It's extra impressive. Um.
36:57
Speaker 1: That's exactly the problem. But as you say, we can
36:59
Speaker 1: do the presence of invisible things because we know some
37:03
Speaker 1: things about how these collisions work, and in particular, we
37:06
Speaker 1: know that momentum is conserved, meaning you have momentum coming
37:10
Speaker 1: into the collision. All that same momentum has to come
37:12
Speaker 1: out of the collision. So if you add up all
37:14
Speaker 1: the stuff that you saw come out of the collision,
37:16
Speaker 1: and we're pretty good at capturing things, and something is missing,
37:19
Speaker 1: it doesn't add up. Then you know something disappeared, something invisible.
37:23
Speaker 1: So we can tell them when we make invisible stuff
37:25
Speaker 1: at the colliders, and in fact we do this all
37:27
Speaker 1: the time. We can't see neutrinos either, and all the
37:30
Speaker 1: time we do this interaction where quarks annihilate and then
37:32
Speaker 1: they turn into a pair of neutrinos, which just basically
37:35
Speaker 1: look invisible. So we we can do this, We've measured this,
37:38
Speaker 1: we can see it's happening. The question is is it
37:41
Speaker 1: also making dark matter? So that's what we're doing. We're
37:44
Speaker 1: trying to tell like is it just making neutrinos or
37:47
Speaker 1: is it making neutrinos and dark matter? All right, So
37:55
Speaker 1: those are the three ways in which we might see
37:58
Speaker 1: dark batter um again just to recab. One of them
38:02
Speaker 1: is to listen for it really really quietly. The other
38:06
Speaker 1: one is to see try to look for places where
38:10
Speaker 1: it's crashing into itself. And the other one is to
38:12
Speaker 1: try to make it here on Earth. That's right, with
38:15
Speaker 1: a million dollars, that's right, exactly so we have those
38:17
Speaker 1: three ways, and you know, we've been doing this for
38:20
Speaker 1: a while, and at first we were sort of just
38:22
Speaker 1: playing around with like could we even see dark matter
38:24
Speaker 1: and the collider, could you look at the center of
38:26
Speaker 1: the galaxy. And people spend a lot of time refining
38:28
Speaker 1: these techniques and making them more and more powerful, and
38:31
Speaker 1: at the same time, we have predictions. We have like
38:33
Speaker 1: clues from the early universe, that's say, dark matter is
38:36
Speaker 1: definitely there, and and these clues from the early universe
38:39
Speaker 1: tell us that probably dark matter came into equilibrium with
38:42
Speaker 1: normal matter, and that means that it's like the energy
38:45
Speaker 1: has sort of like smoothed out, and for that to happen,
38:48
Speaker 1: it has to be able to interact. So we suspect
38:51
Speaker 1: that there's some way for dark matter to interact with
38:53
Speaker 1: normal matter, but it's very indirect clue, and we just
38:56
Speaker 1: don't know how what that is. So we're hoping that
38:59
Speaker 1: we'll be able to see it in one of these experiments,
39:01
Speaker 1: and that india clue suggests that the experiments that we're
39:04
Speaker 1: doing now in the next few years should be able
39:07
Speaker 1: to see dark matter interact with interacting with normal matter
39:11
Speaker 1: at the level necessary to explain that equilibrium. So it's
39:14
Speaker 1: an exciting moment in the search for dark matter. Can
39:16
Speaker 1: you explain what that a clear remans? So you're saying
39:18
Speaker 1: that that you have some sort of feeling that it
39:22
Speaker 1: does feel a special force that we haven't discovered yet
39:27
Speaker 1: because because there's evidence that it has interacted with matter
39:31
Speaker 1: in this way. That's right. We can sort of trace
39:33
Speaker 1: back the history of the universe and the very beginning
39:36
Speaker 1: of the universe just after the Big Bang there was
39:38
Speaker 1: a bunch of matter created, some matter, some some normal
39:41
Speaker 1: matter or some dark matter, right, and then the universe
39:44
Speaker 1: expanded and cooled. Right at some point, the universe cools
39:48
Speaker 1: enough that certain kind of interactions can't happen anymore. So
39:51
Speaker 1: that's what we call that freeze out because it's not
39:53
Speaker 1: hot enough to like make certain things happen anymore. Since
39:57
Speaker 1: the freeze out moment is less interaction between normal matter
40:00
Speaker 1: are in dark matter, we think, right, So we think
40:02
Speaker 1: that before that they were sort of mixing and playing
40:04
Speaker 1: along and interacting, and then the universe cooled down and
40:07
Speaker 1: is less interaction. And we can do those calculations and
40:10
Speaker 1: we could say if there was interaction and things were
40:13
Speaker 1: you know, getting into equilibrium and bouncing off each other.
40:16
Speaker 1: That changes how much dark matter is left in the universe.
40:19
Speaker 1: So we call this a relic density. So the amount
40:21
Speaker 1: of dark matter in the universe now depends on how
40:25
Speaker 1: much it was interacting with normal matter in the early universe,
40:28
Speaker 1: because that changes like how much is made when when
40:31
Speaker 1: normal matter turns into dark matter, or how much disappears
40:33
Speaker 1: when dark matter interacts with itself and turns into normal matter.
40:37
Speaker 1: And so the amount of dark matter we see in
40:40
Speaker 1: the universe now tells us that there was very likely
40:44
Speaker 1: interactions in the early universe. I think what you're saying
40:47
Speaker 1: is that, um, you know, the universe right now only
40:51
Speaker 1: makes sense from what we know of it. If there
40:53
Speaker 1: is some sort of interaction between dark matter and regular matter. Yes, yes, exactly, Okay,
40:59
Speaker 1: But if it turns out that there isn't this special
41:02
Speaker 1: magical unicorn force, then we're sort of toast right like
41:05
Speaker 1: there's then there's really no way for us to really
41:08
Speaker 1: study dark matter. It would be much much harder, and
41:11
Speaker 1: all we can do in that case is lean on gravity,
41:13
Speaker 1: and we're pressing that pretty hard. You know. We're looking
41:15
Speaker 1: at galaxies and how they rotate, but we're also looking
41:18
Speaker 1: at gravitational lensing, we're looking at collisions. We're doing everything
41:22
Speaker 1: we can to try to use the gravitational information, but
41:25
Speaker 1: it's pretty limited. Gravity is a weak force and it
41:27
Speaker 1: doesn't capture a lot of information. So it would be
41:30
Speaker 1: a bit of a tragedy if dark matter doesn't feel
41:32
Speaker 1: anything but gravity, it would make it really hard to
41:35
Speaker 1: ever discover. Is it made of particles, is it made
41:38
Speaker 1: it something else? Is it made of the unic horns?
41:40
Speaker 1: You know, it would be it would be a sad
41:42
Speaker 1: day if we discovered that. So that's that's amazing. It
41:44
Speaker 1: could be that will never ever in the history of
41:46
Speaker 1: humanity until the end of the universe know what this
41:49
Speaker 1: thing is. You sort of sound like you're rooting for
41:52
Speaker 1: that outcome, not either outcome. Are you playing that playing
41:57
Speaker 1: on the tragic arc here? I'm not taking sides between
41:59
Speaker 1: the dark side on the light side. I'm just saying
42:01
Speaker 1: that that that is a distinct possibility, and it's interesting
42:04
Speaker 1: to think about, isn't it to know that maybe there
42:07
Speaker 1: are mysteries will never know the answer to. I'm sure
42:09
Speaker 1: there are mysteries we never know the answer to, and
42:11
Speaker 1: probably the greatest mysteries we don't even know to ask, right,
42:14
Speaker 1: we're that clueless when it comes to the nature of
42:17
Speaker 1: the universe. This is a mystery that we've recently stumbled on,
42:20
Speaker 1: that we've discovered that this huge parts of the universe
42:23
Speaker 1: we don't understand. In fact, most of it the biggest
42:25
Speaker 1: slice of the pie. So we should even be grateful
42:28
Speaker 1: that we know it exists. And now we're getting greedy.
42:30
Speaker 1: We don't want to know everything about it, right, But
42:32
Speaker 1: you're right, it could be that we never know anything
42:34
Speaker 1: more than that it's there and that it has gravity
42:37
Speaker 1: and it plays a role in how things clump. All right.
42:39
Speaker 1: So that's the answer to the question can we ever
42:41
Speaker 1: see dark matter? And the answer is stay tuned, right,
42:45
Speaker 1: Maybe we'll see it, maybe we won't. The answer is
42:47
Speaker 1: keep funding particle physics. The answer is San Daniel a
42:52
Speaker 1: million dollars. That's the answer to every question, isn't it sure? Yeah?
42:56
Speaker 1: What did you have for breakfast? I don't know. I
43:00
Speaker 1: sent Daniel million bucks and I'm still waiting for my eggs, Benedict, Hey,
43:05
Speaker 1: startups don't offer a quick return, okay, right? Right? Or
43:09
Speaker 1: breakfast or breakfast not usually? All right? Well, thanks for
43:13
Speaker 1: joining us. I hope you enjoyed that discussion, and next
43:16
Speaker 1: time you look out there into the universe, I know
43:19
Speaker 1: that they're you are bathing in dark matter, but that
43:22
Speaker 1: we may never or possibly soon be able to see it.
43:26
Speaker 1: That's right, Mysteries the Universe potentially revealed tomorrow on our
43:32
Speaker 1: net next podcast. Stay tuned, all right, see you next time.
43:37
Speaker 1: Thanks for tuning in. If you still have a question
43:48
Speaker 1: after listening to all these explanations, please drop us a line.
43:51
Speaker 1: We'd love to hear from you. You can find us
43:53
Speaker 1: at Facebook, Twitter, and Instagram at Daniel and Jorge That's
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Speaker 1: one word, or email us at back at Daniel and
44:01
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44:05
Speaker 1: and Jorge Explain the Universe is a production of I
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