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What is Mirror Matter? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, I have a question. The particles have families.
0:12
Speaker 1: Oh yeah, actually each particle has a whole set of relatives. Really,
0:17
Speaker 1: so who is the electrons closest cousin? Well, the positron
0:21
Speaker 1: is kind of like the electrons evil twin. Does you
0:25
Speaker 1: have like a twurly mustache? Or whereas where is the
0:29
Speaker 1: opposite color clothes? Yeah, and then it's got the muan,
0:34
Speaker 1: which is like it's heavier cousin, it's more massive cousin,
0:38
Speaker 1: Like it's more fit, like it's bulky or does it
0:41
Speaker 1: just sit around and eat bananas? Nobody knows? Nobody knows.
0:45
Speaker 1: And then the electron even has like hypothetical relatives. What
0:50
Speaker 1: you mean, like long lost relatives. Yeah. Like there might
0:53
Speaker 1: be a super symmetric version of the electron. We call
0:57
Speaker 1: it the selectron. That sounds like a great suit for power.
1:00
Speaker 1: I'd love to select my own relatives. I'm or Hand,
1:20
Speaker 1: a cartoonists and the creator of PhD comics. I'm Daniel.
1:24
Speaker 1: I'm a particle physicist, and there is no super symmetric
1:27
Speaker 1: version of me. Is there an asymmetrical version of you?
1:30
Speaker 1: I don't know, but if there was a super symmetric version,
1:33
Speaker 1: it would be the Daniel or the Daniel Leno, the
1:38
Speaker 1: Daniel Tron. I'm sure you would come up with an
1:41
Speaker 1: awesome name for that version of Daniel. Welcome to our
1:44
Speaker 1: podcast Daniel and Jorge Explain the Universe, a production of
1:48
Speaker 1: I Heart Radio in which we take you on a
1:50
Speaker 1: mental tour of everything that's amazing, that's wonderful, that inspires
1:54
Speaker 1: your curiosity, everything that makes you wonder how does that work?
1:57
Speaker 1: Why is it like that? Why isn't it some other way?
2:00
Speaker 1: We take the whole universe and try to break it
2:02
Speaker 1: down into time little pieces and explain them to you,
2:05
Speaker 1: and we try to take you in a tour of
2:07
Speaker 1: all the things that are out there, all the amazing
2:09
Speaker 1: and incredible types of objects like black holes and neutron stars,
2:15
Speaker 1: and all of the incredible and mysterious particles that are
2:19
Speaker 1: out there and then might be out there. That's right,
2:22
Speaker 1: because part of the journey of understanding the universe is
2:25
Speaker 1: thinking about what's there and what might be there. What
2:28
Speaker 1: would make more sense if the universe had it in it.
2:31
Speaker 1: What do we need to add to our vision of
2:34
Speaker 1: the universe to make it make more sense? What puzzle
2:36
Speaker 1: pieces are we missing? Because that's how scientists explore, right,
2:40
Speaker 1: I know. That's how we kind of probe the unknown.
2:43
Speaker 1: We as we sit around and we think, well, well,
2:45
Speaker 1: I guess you guys sit around on and I went
2:47
Speaker 1: some coffee, and you try to think of what would
2:50
Speaker 1: be what could be out there, what would make sense
2:52
Speaker 1: in terms of the what the equations predict and what
2:55
Speaker 1: the data suggests, and and try to think about what
2:58
Speaker 1: we can discover out there and universe. Yeah, there's sort
3:01
Speaker 1: of two ways to make big discoveries in physics. One
3:04
Speaker 1: is like try to anticipate them, to look at the
3:07
Speaker 1: pattern of what we know and say, what's missing? Would
3:10
Speaker 1: this make more sense if we had another piece? Like
3:13
Speaker 1: if you were doing a puzzle and you fill the
3:14
Speaker 1: whole thing in, is one piece missing? You're going to
3:17
Speaker 1: go out and look for that one piece and you
3:18
Speaker 1: know sort of what to look for, you have expected it.
3:21
Speaker 1: The other way to make discoveries just to like go
3:23
Speaker 1: out there is an explore and see what you're find
3:26
Speaker 1: and maybe you're run into something amazing you didn't expect.
3:28
Speaker 1: That's also fun, But there's a lot of times that
3:31
Speaker 1: we can't just do that. We don't have necessarily the
3:33
Speaker 1: way to explore. We have to think about it in
3:35
Speaker 1: advance and try to figure out in advance what is
3:38
Speaker 1: it we should be looking for. I usually find my
3:40
Speaker 1: puzzle pieces in between my couch cushions, or or under
3:45
Speaker 1: the or on the table. I borrowed a bunch of
3:48
Speaker 1: puzzles from some friends and I put the first one
3:51
Speaker 1: together and it was missing a piece, and it had
3:54
Speaker 1: an extra piece from another one of the puzzles. What
3:58
Speaker 1: I think your friends are trying to drive you crazy
4:00
Speaker 1: to think so, because then the next puzzle was the same.
4:02
Speaker 1: So by the time the next puzzle, I had this
4:05
Speaker 1: like two extra random pieces and two puzzles each missing
4:08
Speaker 1: a piece. And it wasn't symmetric LIKEE was missing from
4:12
Speaker 1: the other one. No, it was like a cycle. It
4:14
Speaker 1: was like you have to finish all six to finish
4:16
Speaker 1: any of them. It was torture. Um, I think they're
4:19
Speaker 1: trying to gas light you in the puzzle version of
4:21
Speaker 1: gas lighting, trying to puzzle light you down exactly. But
4:25
Speaker 1: you know, I have to take issue with what you
4:26
Speaker 1: said earlier that physicists, when we try to have ideas,
4:28
Speaker 1: we sit around and think about stuff. Why is that
4:31
Speaker 1: you think about It's just like sitting around these days
4:34
Speaker 1: trying to do my thinking. Well, I'm active, I'm going
4:36
Speaker 1: for a walk to think about stuff. I'm doing jumping
4:38
Speaker 1: jack to think up new theories. I thought you were
4:41
Speaker 1: going to complain that you actually lie down when you
4:43
Speaker 1: think physics. Is that how you get your creative ideas?
4:47
Speaker 1: Curl up under the desk or something. My best ideas
4:51
Speaker 1: come when I have my feed up. For sure. Post
4:54
Speaker 1: definitely leads to creativity. Yeah. So we know a lot
4:57
Speaker 1: about the universe, and we know all a lot of
4:59
Speaker 1: the particles that are out there that make up matter,
5:02
Speaker 1: that might make up matter, and that um make up
5:05
Speaker 1: other things that maybe are not as useful to the universe.
5:09
Speaker 1: But there are also a lot of missing pieces in
5:11
Speaker 1: the universe. There's a lot of empty places in our
5:15
Speaker 1: ideas of particles and matter that could be filled by
5:19
Speaker 1: new particles. That's right, because when we look at the particles,
5:22
Speaker 1: we don't just want to make a list and say here,
5:25
Speaker 1: all the particles in the universe were done. We want
5:27
Speaker 1: to understand that. We want to fit them together into
5:29
Speaker 1: patterns because those patterns are clues, clues that will lead
5:33
Speaker 1: us to be able to pull back a layer of
5:35
Speaker 1: reality and see what's underneath those particles, what are the tiny,
5:39
Speaker 1: even smaller particles that make them up all the way
5:42
Speaker 1: down to the smallest bits of the universe. So the
5:45
Speaker 1: way to do that is to organize our knowledge and
5:47
Speaker 1: look for holes. For example, before we discover the top cork,
5:51
Speaker 1: we had five corks and they fit together in two
5:53
Speaker 1: pairs plus one lonely bottom cork, And we thought, where's
5:57
Speaker 1: the partner for the bottom cork? It must be out there,
6:00
Speaker 1: and we went and looked for it and found it.
6:02
Speaker 1: So this strategy of organizing our knowledge and looking for
6:05
Speaker 1: holes and gaps and symmetries is a really productive way
6:08
Speaker 1: to find new things. And so today on the program,
6:11
Speaker 1: we'll be talking about one such set of wholly particles
6:15
Speaker 1: that might exist and that might answer a lot of
6:17
Speaker 1: questions about our understanding of the universe. So we'll be
6:21
Speaker 1: asking the question, what is mirror matter and why is
6:31
Speaker 1: it so hard to say? It is a little hard
6:33
Speaker 1: to say. I feel a little punk tight just saying
6:35
Speaker 1: mirror matter mirror Well, you know, there's an a whole
6:38
Speaker 1: sociological question we'll dig into later about why mirror matter
6:42
Speaker 1: is not so popular among theoretical physicists. But One answer
6:46
Speaker 1: might be that it's just kind of hard to say.
6:49
Speaker 1: Do you think that matters? It's more fun to say
6:52
Speaker 1: dark matter antimatter than mirror matter. Don't, don't, don't use
6:56
Speaker 1: alliteration when you when you discover something new and amaze
7:00
Speaker 1: in physics, you know what you're saying and ours ours
7:02
Speaker 1: are just horror to say their horror, horror. There there
7:05
Speaker 1: are harder horror choice exactly? Is that why particle physics
7:12
Speaker 1: has some problems there? Yeah? I think so? All right? So,
7:16
Speaker 1: as usual, Daniel went out there into the wiles of
7:19
Speaker 1: the Internet to ask if people were familiar with this
7:22
Speaker 1: idea of mirror matter. So thanks to everybody who sent
7:25
Speaker 1: in their speculations about what mirror matter might be. If
7:28
Speaker 1: you'd like to speculate on a future topic of one
7:31
Speaker 1: of our podcast episodes, please write to us two questions
7:35
Speaker 1: at Daniel and Jorge dot com. We'd love to have
7:38
Speaker 1: you participate. So think about it for a second before
7:40
Speaker 1: you listen to these answers. If someone ask you what
7:43
Speaker 1: is mirror matter, or ask you how to pronounce it?
7:46
Speaker 1: For that matter, what would you say? There is what
7:50
Speaker 1: people had to say something that reflected um like a
7:54
Speaker 1: positive trium versus uh. You know, it's kind of the
7:56
Speaker 1: opposite of each of the particles that we have. I
7:59
Speaker 1: can only guess, and the name probably it's the matter
8:03
Speaker 1: that imitates the matter that comes close to or get
8:09
Speaker 1: gets in contact with. I have no idea. So there
8:13
Speaker 1: are two things that come to my mind immediately. The
8:16
Speaker 1: first one is antimater, but I think that this answer
8:20
Speaker 1: is to straightforward, so I don't think this is the
8:22
Speaker 1: right concept to your question. So the second thing that
8:26
Speaker 1: comes to my mind, that's supersymmetry. I assume that mirror
8:31
Speaker 1: matter talks about particle physics, and I don't know a
8:34
Speaker 1: whole lot about it, but from what I know, I
8:38
Speaker 1: think mirror matter wants to kind of explain why the
8:45
Speaker 1: weak force is the only one that does not respect
8:48
Speaker 1: the mirror reflection symmetry That sounds made up, sounds like
8:52
Speaker 1: something i'd hear on Star Trek, but I'm gonna go
8:55
Speaker 1: with it relates to supersymmetry. Those are words I've heard before,
9:00
Speaker 1: or I wouggest that mirror matter is matter with the
9:04
Speaker 1: opposite handedness. Mirror matter is maybe matter with particles of
9:10
Speaker 1: opposite spin in charge. I'm immediately thinking of anti matter,
9:15
Speaker 1: but I'm presuming it's something different, all right. I like
9:19
Speaker 1: the star Trek reference. We should be writing for star Trek, Daniel.
9:25
Speaker 1: Star Trek is just stealing from reality. You know, reality
9:28
Speaker 1: is so weird that inspires hilarious fiction. But people seem
9:32
Speaker 1: to have sort of the idea that it's like a matter,
9:34
Speaker 1: but it's somehow their mirror image. So I guess it
9:36
Speaker 1: is a pretty good name. Kind of like there's some
9:39
Speaker 1: kind of idea about symmetry and handedness and spin, and
9:44
Speaker 1: there seems to be a general understanding that there are
9:47
Speaker 1: these symmetries that everything we know could be reflected. There
9:50
Speaker 1: could be a whole other set of stuff, and exactly
9:53
Speaker 1: the way that there are is anti matter. Now we're
9:55
Speaker 1: talking a moment about what mirror matter is. It's not
9:57
Speaker 1: the same thing as anti matter, but it does share
9:59
Speaker 1: that thing in common that it's a reflection of the
10:02
Speaker 1: particles we know. It tells us something about the symmetries
10:05
Speaker 1: that are built into the universe and the ideas that
10:07
Speaker 1: there's potentially more than one of these reflections, you know,
10:10
Speaker 1: the reflection of all the matter particles into antimatter particles.
10:14
Speaker 1: And you can also have the reflection potentially of matter
10:17
Speaker 1: particles into these mirror matter particles. So it's in the
10:20
Speaker 1: same sort of family of ideas, but it's just a
10:22
Speaker 1: different kind of reflection. Man, I feel like we were
10:26
Speaker 1: living in a house of mirrors or a universe of mirrors.
10:29
Speaker 1: It's crazy and it's amazing, and it blows my mind
10:32
Speaker 1: how many of these reflections there are. Because you know,
10:35
Speaker 1: we talked about antimatter, and we will talk about mirror matter,
10:37
Speaker 1: but then there are also these particle families, Like the
10:39
Speaker 1: electron is not just reflected into the muon, it's reflected
10:43
Speaker 1: into the muan and the tao. And so the whole
10:46
Speaker 1: structure that we understand of the universe of particle physics
10:49
Speaker 1: is really built around all these symmetries and reflections. I mean,
10:52
Speaker 1: that's what we're trying to do, is like organize these
10:55
Speaker 1: things into patterns, and the look at the patterns and say,
10:57
Speaker 1: what does that pattern mean about the universe? Means that
11:01
Speaker 1: maybe you shouldn't have decorated your whole universe with mirrors.
11:05
Speaker 1: Perhaps you know who did, right? Who put up all
11:09
Speaker 1: these mirrors? Right? This place is like a crazy fun house.
11:12
Speaker 1: Why is it so hard to understand? No, it's it's fascinating,
11:15
Speaker 1: you know, just like you can ask the question, you know,
11:17
Speaker 1: why is there no antimatter left in the universe. You
11:19
Speaker 1: can ask the question like, well, why do we have
11:21
Speaker 1: antimatter at all? Right? Why is there this symmetry? What
11:24
Speaker 1: does it mean about the universe that there seems to
11:27
Speaker 1: be this balance in the list of particles, but not
11:30
Speaker 1: in their actual existence, right and so so and some
11:33
Speaker 1: people also mentioned the idea of supersymmetry, But mirror matter
11:37
Speaker 1: is not related to supersymmetry, right, that's right. Supersymmetry is
11:40
Speaker 1: yet another hypothetical reflection and that looks to try to
11:44
Speaker 1: build a symmetry into the universe. It says, we have
11:47
Speaker 1: some particles called fermions and make up matter particles, and
11:50
Speaker 1: other particles called bosons that make up forces like photons
11:53
Speaker 1: and z bosons. What if each of those has a
11:56
Speaker 1: corresponding particle on the other side, Every fermion has some
12:00
Speaker 1: boson that corresponds to it, So the electron has a selectron,
12:04
Speaker 1: and the mulan has a smew on, And then every
12:06
Speaker 1: boson like the photon, has a fermion partner. So the
12:10
Speaker 1: photon would have a photino and the w particle would
12:13
Speaker 1: have a we know, for example, and so that again
12:16
Speaker 1: just reflects the whole set of standard model particles over
12:20
Speaker 1: into a new set of hypothetical particles that we have
12:22
Speaker 1: not yet discovered and are not the same as antimatter
12:25
Speaker 1: and not the same as mirror matter. It's just another
12:29
Speaker 1: kind of reflection that tells you about how we're always
12:31
Speaker 1: looking for symmetries in the universe. But this one seems
12:35
Speaker 1: to claim the mantle of mirror matter, Like it just
12:38
Speaker 1: grabs that word and says, I'm the I'm the mirror
12:41
Speaker 1: type of matter. Yeah, exactly, and it's mostly championed by
12:45
Speaker 1: like one guy in Australia. Wait. Wait, this is a
12:50
Speaker 1: major physics theory that has a support of exactly one physicists,
12:56
Speaker 1: not exactly one physicist. But you know, um, not that
12:59
Speaker 1: many physicist believe in mirror matter. Although other people have
13:02
Speaker 1: ideas that are very similar to mirror matter, they just
13:05
Speaker 1: don't call it that. So maybe it's just the naming issue.
13:07
Speaker 1: People like, we hate that name. We're gonna come up
13:09
Speaker 1: with a similar idea and call it something else. Yeah,
13:13
Speaker 1: you're telling me that this idea also has other names,
13:16
Speaker 1: like alice matters, or shadow matter. Yeah, that's that's all
13:19
Speaker 1: the same one idea with several different potential names. So
13:22
Speaker 1: I guess, you know, the community around mirror matter was
13:25
Speaker 1: trying out a few things to see what would stick,
13:27
Speaker 1: and I guess mirror matter is the most popular. I
13:29
Speaker 1: kind of like alice matter because it has the like
13:31
Speaker 1: literary reference to it. I like shadow matter. It sounds
13:35
Speaker 1: like something out of Dungeons and Dragons. You're gonna roll
13:39
Speaker 1: a die and try to use your shadow matter sword. Yeah,
13:42
Speaker 1: the shadow mage uses a shadow matter sword. Of course.
13:46
Speaker 1: I think it's too similar to dark matter, you know,
13:48
Speaker 1: because then people are like, well, if you put matter
13:51
Speaker 1: in the shadows, does it become dark matter? You know,
13:53
Speaker 1: it's very confusing. All right, well let's jump right into
13:56
Speaker 1: Daniel what let's answer the question what is mirror better.
14:00
Speaker 1: I'm guessing it has to do it's sort of like
14:02
Speaker 1: supersymmetric matter. But maybe you're saying it's a different kind
14:05
Speaker 1: of mirror. Yeah, it's a different kind of mirror. So
14:08
Speaker 1: whenever we create a new set of hypothetical particles to
14:11
Speaker 1: balance the particles we have, it's because we see an imbalance,
14:15
Speaker 1: we see something asymmetric, and we wonder why do we
14:17
Speaker 1: have positive charge particles and not negative for example, Or
14:20
Speaker 1: you know, why do we have fermion matter and boson
14:23
Speaker 1: forces not the opposite. So in this case, we've created
14:26
Speaker 1: a whole new set of particles, the mirror particles, to
14:29
Speaker 1: try to balance the parity asymmetry of the universe, the
14:32
Speaker 1: symmetry about being reflected in the mirror? Does the universe
14:35
Speaker 1: look the same when you reflected in the mirror? And
14:38
Speaker 1: we've talked on the podcast several times about how our
14:41
Speaker 1: universe seems to be weirdly left handed, like some parts
14:45
Speaker 1: of the standard model, the forces that are involved like
14:48
Speaker 1: to only talk to particles that are left handed and
14:50
Speaker 1: not right handed, and that's weird. I guess it all
14:52
Speaker 1: sort of goes back to the concept of particles and
14:55
Speaker 1: matter having um like properties or values of things charge
15:01
Speaker 1: or color or what's the other one, spin spin, favor,
15:06
Speaker 1: spin flavorite. They have all these properties and so, and
15:10
Speaker 1: really in the math you can just flip them and
15:13
Speaker 1: such a particle could still exist. Like mathematically you can
15:16
Speaker 1: flip these things, even though you may not necessarily see
15:20
Speaker 1: them in nature. Right, That's kind of the idea, is
15:22
Speaker 1: that particles has these properties, and you can flip some
15:25
Speaker 1: of them, and sometimes you see particles that have them,
15:28
Speaker 1: and sometimes you don't see particles that have them. Yeah,
15:30
Speaker 1: that's exactly right. We look at the structure of our
15:34
Speaker 1: theory and we wonder if it's symmetric. We're like, well,
15:36
Speaker 1: what happens if you flip all these things? You know,
15:38
Speaker 1: if you flip the charges from positive negative, or you
15:42
Speaker 1: flip everything for the minus z access to the positive
15:44
Speaker 1: z axis, or you run time backwards, and all these things.
15:47
Speaker 1: We wonder, like, is our theory symmetric? And so as
15:50
Speaker 1: you say, you can take this this set of particles
15:52
Speaker 1: and you can say, well, do we have the opposite
15:54
Speaker 1: set in this sense or in this other sense, or
15:56
Speaker 1: in this third sense? Do we have the opposite set?
15:59
Speaker 1: You know, do exist? And if not, then why not?
16:02
Speaker 1: Because that tells you something about the universe, right, like
16:04
Speaker 1: why do we only have negatively charged electrons and not
16:08
Speaker 1: positively charged electrons, you know, positrons? And so it's it's
16:12
Speaker 1: interesting because you feel like there must be a reason.
16:14
Speaker 1: We like to think that that the universe should be symmetric,
16:17
Speaker 1: because that makes sense because if it's asymmetric, then like
16:21
Speaker 1: who made that choice? Right, why matter or not antimatter?
16:24
Speaker 1: Did somebody flip a coin? Is it totally random? And
16:27
Speaker 1: we don't like that. In physics, we don't like things
16:28
Speaker 1: that don't have explanations, So we like things to be
16:31
Speaker 1: symmetric because then then they don't need explanations. So we
16:34
Speaker 1: take our theory, we look for all the things that
16:36
Speaker 1: are asymmetric, and then we try to fill in those holes.
16:39
Speaker 1: But I guess when when you know, why do physics
16:40
Speaker 1: have a preference for symmetry, like um, when you couldn't
16:44
Speaker 1: you ask the same question like who made the universe symmetric?
16:47
Speaker 1: Like if the universe was symmetric, wouldn't you ask the
16:50
Speaker 1: same question? That's a great question, and that really goes
16:53
Speaker 1: to philosophy. Um, And it's a question of what's simple.
16:57
Speaker 1: You know, when we look at a physics theory, we
16:58
Speaker 1: have questions about it. And when we compare two different
17:01
Speaker 1: physics theories, we want the one that's simpler, that needs
17:04
Speaker 1: like less explanation and fewer ideas. And that's sort of um.
17:08
Speaker 1: You know, we don't know why the universe is that way,
17:11
Speaker 1: but it does seem to work that way. That's simpler
17:13
Speaker 1: ideas seem to work best, and so I would just
17:16
Speaker 1: ask fewer questions about a theory that was symmetric than
17:20
Speaker 1: the theory that was asymmetric, because a theory that's symmetric,
17:23
Speaker 1: you're right, there's no reason why the universe has to
17:26
Speaker 1: be symmetric. But it just seems to make more sense
17:29
Speaker 1: intuitively or or aesthetically. But you know, that's not a
17:32
Speaker 1: scientific feeling at all. That's sort of like a philosophical
17:35
Speaker 1: um um or personal aesthetic feeling. Yeah, that's what I mean.
17:39
Speaker 1: It's like if one of your kids was really well
17:41
Speaker 1: behaved on the other one was a lot of trouble,
17:43
Speaker 1: and you'd be like, yeah, that that makes sense in
17:45
Speaker 1: the universal cosmic balanced sense. I think there is something there, though,
17:53
Speaker 1: because if the universe is asymmetric, there are lots of
17:55
Speaker 1: ways it could be asymmetric, but there's only really one
17:58
Speaker 1: way to be symmetric. And so if you're asymmetric, and
18:01
Speaker 1: you're asymmetric in one particular way, then you have to
18:03
Speaker 1: wonder why are we living in a multiverse where every
18:06
Speaker 1: choice for that asymmetry is made. Are there other universes
18:09
Speaker 1: out there that are antimatter instead of matter, for example,
18:12
Speaker 1: or are we living in a simulation where this was
18:14
Speaker 1: decided by the people who ran the simulation. It's just
18:17
Speaker 1: sort of unsatisfying to not have an explanation if there
18:20
Speaker 1: are lots of options, whereas if there's only one option,
18:22
Speaker 1: then you know that's just the option. You can ask like,
18:24
Speaker 1: why is there only that option? And that's a deeper question,
18:28
Speaker 1: like if both your kids are well behaved, you'd be suspicious.
18:31
Speaker 1: I'd give my wife credit if that was the case. Unfortunately,
18:34
Speaker 1: we don't live in that universe. Al right. Well, okay,
18:39
Speaker 1: so mirror matter, then, is a matter that also breaks
18:43
Speaker 1: one of these symmetries in nature that you have, and
18:46
Speaker 1: it's sort of related to the weak force, right. I
18:49
Speaker 1: find it a little confusing to think about parody because
18:52
Speaker 1: it's hard to think about whether it matters if you're
18:55
Speaker 1: reflected in the mirror, whether the universe prefers right handed
18:59
Speaker 1: or left handed. Now it's the same basic concept, but
19:02
Speaker 1: I think it's easier to think about whether it matters
19:05
Speaker 1: if you rotate your experiment, whether the universe has a
19:08
Speaker 1: preferred direction, which seems obviously crazy. Imagine you throw a
19:12
Speaker 1: ball and it follows some law of physics, right, parabolo
19:15
Speaker 1: goes up and it comes down. Now you watch that
19:17
Speaker 1: same ball toss, but now you're standing on your head.
19:20
Speaker 1: It looks a little different, right because you're you've rotated yourself,
19:24
Speaker 1: But the same laws apply, and like you can still
19:26
Speaker 1: apply the laws of physics to the ball. Moving shouldn't
19:29
Speaker 1: matter if you're standing on your head, right, except that
19:32
Speaker 1: now down means up and up means down. Yeah, exactly,
19:35
Speaker 1: you have to put some minus signs in there, but
19:37
Speaker 1: the same laws do apply. Now you don't see exactly
19:40
Speaker 1: the same thing, Like it looks different if you're standing
19:42
Speaker 1: on your head, but the same rules apply. And so
19:45
Speaker 1: parody is sort of like that, like if you reflect
19:48
Speaker 1: something into the mirror, do the same rules apply or not?
19:52
Speaker 1: And people for a long time thought, well, of course,
19:54
Speaker 1: like just because you're doing in the mirror, the same
19:56
Speaker 1: rules should apply. Like it would be nonsense if our
19:59
Speaker 1: you niverse was somehow left handed and it looked different
20:02
Speaker 1: in the mirror, and like the mirror was right handed,
20:05
Speaker 1: it would be weird. They would be weird. And people
20:07
Speaker 1: just assumed for like, you know, as long as people
20:10
Speaker 1: had this idea, until about fifty years ago, people assumed
20:13
Speaker 1: the universe was symmetric in the mirror that if you
20:15
Speaker 1: didn't experiment, it would look the same in the mirror
20:18
Speaker 1: that you know that the mirrors that in the in
20:20
Speaker 1: the mirror world, the same laws of physics would apply.
20:23
Speaker 1: Now we can't actually go to the mirror world. We
20:25
Speaker 1: can't do the mirror experiment. Right, the ideas we do
20:28
Speaker 1: experiments in our universe and we think about what they
20:31
Speaker 1: would look like in the mirror world. We try to
20:33
Speaker 1: we imagine that all the experiments we do in our
20:36
Speaker 1: universe would look the same in the mirror world. But
20:40
Speaker 1: but he neverse is a little bit weirder than that.
20:43
Speaker 1: The universe is super duper weird in fact, and it
20:47
Speaker 1: was about fifty years ago the people realized, you know,
20:49
Speaker 1: we never actually checked to see if this is true
20:52
Speaker 1: for all the different kinds of interactions. They had checked
20:54
Speaker 1: for the strong force, they had checked for electromagnetism, and
20:58
Speaker 1: parody was preserved like everything a perfect sense, but nobody
21:01
Speaker 1: had actually checked for the week interaction. And then one
21:05
Speaker 1: summer people wrote this paper realizing, wow, nobody's ever checked
21:08
Speaker 1: this one thing. Somebody should do it, and the paper
21:10
Speaker 1: came out, and then over Christmas vacation, a scientist at Columbia,
21:14
Speaker 1: the famous professor C. S. Wo. She did the experiment
21:18
Speaker 1: and she set up a system that would look different
21:20
Speaker 1: in the mirror. So they broke the mirror. And that
21:23
Speaker 1: was seven years of seven decades of bad physics. Luck
21:26
Speaker 1: Is that kind of what happened? Yeah, exactly. All right,
21:29
Speaker 1: let's jump into the details here about the weak floorce
21:32
Speaker 1: and symmetry and left and right handedness. But first let's
21:35
Speaker 1: take a quick break. All right, we're talking about mirror matter.
21:52
Speaker 1: And this is um not related to how I looked
21:55
Speaker 1: like in the morning when I look in the mirror, Daniel,
21:58
Speaker 1: that's right, but there is no face. Six could explain
22:00
Speaker 1: that this relates to how particles look in the mirror,
22:04
Speaker 1: because particles, as weird as they are, they have this
22:07
Speaker 1: bizarre property that they're either left handed or right handed.
22:11
Speaker 1: And of course particles don't have hands right, but they
22:14
Speaker 1: do have a property which gets inverted in the mirror
22:18
Speaker 1: sort of the way that left handedness and right handedness does.
22:22
Speaker 1: And that's when you compare the direction they spin with
22:25
Speaker 1: the direction they're moving. And because clockwise spin in the
22:29
Speaker 1: mirror still looks clockwise, whereas moving in the mirror can
22:32
Speaker 1: get flipped in the other direction. So a left handed
22:35
Speaker 1: particle um looks like a right handed particle in the mirror,
22:39
Speaker 1: and a right handed particle in our universe looks like
22:41
Speaker 1: a left handed particle in the mirror. Right, It's kind
22:44
Speaker 1: of like the mnemonic, you know, like when you use
22:47
Speaker 1: your hand, like you point your thumb one way and
22:49
Speaker 1: then you curl your fingers, and that that's sort of
22:52
Speaker 1: like a handedness kind of thing for particles. Right, Like
22:54
Speaker 1: the thumb could be pointing to where its going, and
22:57
Speaker 1: the curl of your finger points to how it's spinning.
22:59
Speaker 1: And so when you look in the mirror, that looks
23:02
Speaker 1: not the same, that's right, And that tells you if
23:04
Speaker 1: a particle is left handed or right handed, is it
23:06
Speaker 1: moving in the same direction as its spin vector is pointing,
23:10
Speaker 1: or is it moving in the opposite direction. And in
23:12
Speaker 1: a mirror, left handed particles turned into a right handed particle. Now,
23:15
Speaker 1: the weird thing is that the weak force, the weak
23:19
Speaker 1: nuclear force, only interacts with left handed particles. It totally
23:23
Speaker 1: ignores right handed particles. That's the big asymmetry that they're
23:28
Speaker 1: the force ignores these other particles. It doesn't interact with
23:31
Speaker 1: them at all, you know how some forces interact with
23:34
Speaker 1: some particles and not others, Like the strong nuclear force
23:37
Speaker 1: doesn't interact with electrons. Electrons just totally ignore the strong force.
23:41
Speaker 1: Oh I see, it just doesn't apply to that. It
23:45
Speaker 1: just doesn't apply. So there are actually two kinds of electrons.
23:49
Speaker 1: There's the left hand electron and the right hand electron.
23:52
Speaker 1: The weak force only interacts with left handed electrons. It
23:55
Speaker 1: doesn't interact with right handed electrons at all. And that
23:59
Speaker 1: to do right handed electrons exists? Are there? Are they
24:02
Speaker 1: out there right lying around ignoring the weak force absolutely
24:06
Speaker 1: all the time? There are left hand, right handed electrons,
24:09
Speaker 1: and only left handed electrons interact with the weak force.
24:12
Speaker 1: And that's what causes this parity asymmetry. In the mirror,
24:16
Speaker 1: the weak force interacts with right handed electrons, but in
24:18
Speaker 1: our universe it only talks to left handed particles neutrinos, electrons,
24:23
Speaker 1: and quarks. That is so bizarre, it's really weird. It's
24:27
Speaker 1: a huge asymmetry. And it's not like a little asymmetry
24:30
Speaker 1: like it talks to left handed particles more than right
24:32
Speaker 1: handed particles. It's complete asymmetry. Only ever talks to left
24:36
Speaker 1: handed particles, never too right handed particles. What if I
24:41
Speaker 1: threw and right handed electron, like, nothing would stop it
24:44
Speaker 1: in terms of the strong force, in terms of the
24:46
Speaker 1: weak force, in terms of the weak force, Yeah, that's right,
24:49
Speaker 1: but you don't really notice that because the weak force
24:51
Speaker 1: is super weak, and right hand electrons still feel electromagnetism
24:55
Speaker 1: right the photons, and it's biased, but it's a weak
24:58
Speaker 1: by that's right, um and and so most of the
25:03
Speaker 1: interactions work with both of them. But the weak force
25:05
Speaker 1: only talks to the left handed particles. And that's why,
25:08
Speaker 1: for example, we've never seen a right handed new trino,
25:12
Speaker 1: because neutrinos only feel the weak force, and so the
25:16
Speaker 1: only way to talk to neutrinos is through the weak force.
25:19
Speaker 1: But the weak force doesn't talk to right handed particles,
25:22
Speaker 1: and so we've never seen a right handed new trino. Wow,
25:25
Speaker 1: it's not just that it it has a bias against
25:29
Speaker 1: the electron being right handed, has a bias against any
25:31
Speaker 1: particle being right handed. That's right. There are two kinds
25:34
Speaker 1: of every particle, that is, the left handed kind and
25:36
Speaker 1: the right handed kind. And the weak force only talks
25:38
Speaker 1: to left handed quarks. To what left handed electrons, left
25:41
Speaker 1: handed muans? Left handed new trinos it never talks or
25:44
Speaker 1: right handed anybody. It kind of makes me wonder if
25:46
Speaker 1: there's a right handed weak force. Have you guys thought
25:49
Speaker 1: about that? Like, is there are? Maybe there are two forces?
25:52
Speaker 1: And that's the genesis of the idea for mirror matter.
25:58
Speaker 1: This kind of it's me and the from Australia. No,
26:01
Speaker 1: but that's exactly. This kind of asymmetry makes you wonder
26:05
Speaker 1: is there's something out there to balance it? Right? That
26:07
Speaker 1: was exactly the thought you just had live right here
26:09
Speaker 1: on the program. And that's the whole motivation for this
26:12
Speaker 1: entire program of physics is can we find something else
26:15
Speaker 1: out there to balance it? You didn't like that asymmetry,
26:18
Speaker 1: and you're like, let's fill in that gap, let's balance
26:20
Speaker 1: the universe. And that's exactly what we're trying to do
26:22
Speaker 1: with mirror matter. Yeah, because I believe in cosmic justice.
26:28
Speaker 1: And so there's sort of two different sets of ideas there.
26:31
Speaker 1: One is a minimal idea and say well, can we
26:33
Speaker 1: restore the balance by saying, well, maybe there is a
26:36
Speaker 1: right handed neutrino out there. We've just never seen it
26:39
Speaker 1: because we can't interact with it with our weak force.
26:42
Speaker 1: So maybe there's a right handed neutrino, and then like
26:44
Speaker 1: some other version of the weak force that's biased in
26:47
Speaker 1: the other way, like a w prime boson and is
26:50
Speaker 1: the prime boson, And and that's a cool idea, um,
26:54
Speaker 1: and that would restore some balance. I mean it would.
26:57
Speaker 1: It would mean that the universe sort of cracked in half.
27:00
Speaker 1: It's not really symmetric, it's sort of like cracked in half.
27:02
Speaker 1: And we have two different pieces, and we happen to
27:05
Speaker 1: be on the left handed part of it. The mirror
27:07
Speaker 1: matter takes a step further and it says, instead of
27:10
Speaker 1: just adding a right handed new trino and a new
27:13
Speaker 1: force to talk to it, let's copy all of the particles.
27:16
Speaker 1: So let's take the electron and make a mirror electron,
27:20
Speaker 1: and let's take the quarks and make mirror corks. And
27:23
Speaker 1: let's have a whole new set of forces, a mirror
27:26
Speaker 1: strong force and mirror weak force and mirror electric force.
27:29
Speaker 1: And in that whole mirror then parody is violated in
27:33
Speaker 1: the opposite direction. So rather than just adding the minimal
27:36
Speaker 1: pieces to our standard model to balance parody, reflect the
27:39
Speaker 1: whole thing and this have the whole thing be balanced
27:42
Speaker 1: in the other direction. But well, wait, I thought that
27:46
Speaker 1: right handed electrons did exist. Right hand electrons do exist. Yeah,
27:50
Speaker 1: And so this idea would say, well, let's make mirror
27:52
Speaker 1: electrons and you'll have both left and right handed mirror electrons. Right,
27:57
Speaker 1: and we have left handed neutrino, so this would make
28:01
Speaker 1: right handed mirror neutrinos. Oh, I see, it's like a
28:05
Speaker 1: whole different It's like a whole new set of two hands. Yeah, exactly.
28:10
Speaker 1: It's like you got one family, you know, where everything
28:12
Speaker 1: is balanced, except the neutrinos only left handed. And instead
28:15
Speaker 1: of just inviting one more neutrino that's right handed, invite
28:18
Speaker 1: a whole other family, right if they have a right
28:22
Speaker 1: handed neutrino. It's it's more like in our family, we
28:26
Speaker 1: only like the kids that are right hand the left handed,
28:29
Speaker 1: and instead of making up because we have kids that
28:32
Speaker 1: are left handed, right now, we have kids that are
28:35
Speaker 1: right handed, we just don't like him. And to balance
28:38
Speaker 1: it out, maybe there's another family out there down the
28:40
Speaker 1: street that that has right and left handed kids, but
28:44
Speaker 1: they have a different, different preference, different they make different
28:47
Speaker 1: parenting mistakes that balance our parenting mistakes, and a whole
28:52
Speaker 1: and the terrible in a whole mirror symmetric play. That's right.
28:55
Speaker 1: The universe doesn't care if you make parenting mistakes as
28:57
Speaker 1: long as somebody else is making the opposite one. That's
29:01
Speaker 1: the physics approach to parenting. Symmetry is restored and all
29:06
Speaker 1: is good. Oh man, I'd love to see maybe wouldn't
29:10
Speaker 1: love to see how things work in your house and
29:12
Speaker 1: then you um, But there's some fascinating twists. They're like.
29:16
Speaker 1: One of them is gravity is not mirrored. If there
29:19
Speaker 1: is a graviton, this particle that transmits gravity and a
29:23
Speaker 1: quantum theory of gravity, it would not be mirror. There
29:26
Speaker 1: would not be like a mirror graviton. It's like it
29:29
Speaker 1: sits at the edge of the mirror or something. Yeah,
29:31
Speaker 1: because it sits at the mirror line. Because gravity is
29:33
Speaker 1: how we bend space, and there's only one space. We
29:36
Speaker 1: think that our particles and the mirror particles live in
29:39
Speaker 1: the same space. If they have their own graviton, that
29:41
Speaker 1: have to have their own space, and that would be weird.
29:44
Speaker 1: And so yeah, it sits on the mirror itself. Okay.
29:47
Speaker 1: So the idea of mirror matter then is that there's
29:50
Speaker 1: a whole set of matter particles that are mirrored somehow,
29:55
Speaker 1: in this bias that the weak force has, and there's
29:58
Speaker 1: a whole different weak force that has a different bias. Yeah,
30:02
Speaker 1: if you build that parody violation experiment that Dr Wu's
30:06
Speaker 1: experiment out of mirror matter and did the experiment, you
30:09
Speaker 1: would get the opposite results. I guess my question is
30:12
Speaker 1: where does this where's all? Where is all this mirror matter?
30:14
Speaker 1: Like you sit on top of us? Is it next
30:16
Speaker 1: to us? Is it kind of like a parallel universe
30:19
Speaker 1: kind of thing. Well, we don't know if it exists,
30:21
Speaker 1: first of all, and if it does exist, to be
30:23
Speaker 1: very hard to see. And so in that respects it's
30:26
Speaker 1: sort of similar to dark matter, because we suspect we
30:29
Speaker 1: might only have gravitational interactions with it that we'll talk
30:32
Speaker 1: in a moment about other ways we might probe it,
30:35
Speaker 1: And so it could be right here on top of
30:36
Speaker 1: us without us interacting with it. A right, Remember that
30:39
Speaker 1: the universe is filled with all sorts of invisible stuff
30:42
Speaker 1: that you cannot sense, like all the new trinos that
30:45
Speaker 1: are flying through you right now, that you don't interact
30:47
Speaker 1: with all the dark matter that surrounds the Earth and
30:50
Speaker 1: fills your room. You can't see or touch or interact
30:53
Speaker 1: with So it's possible to share space physically overlap with
30:57
Speaker 1: other kinds of matter that you if you do not
31:00
Speaker 1: direct with them. And mirror matter, if it exists, we
31:03
Speaker 1: may only interact with it gravitationally, which is very very weak,
31:06
Speaker 1: which means essentially we wouldn't sense it. And so if
31:08
Speaker 1: there is mirror matter, could be right here on top
31:10
Speaker 1: of us, but it could also be out there in
31:12
Speaker 1: the universe, separated from us. Well, yeah, I guess, yeah,
31:15
Speaker 1: I guess like dark matter and the trains, they're all
31:17
Speaker 1: sitting on top of us, but we don't feel them.
31:19
Speaker 1: Maybe there's a whole bunch of right handed laws and
31:24
Speaker 1: right handed matter that's sitting on top of us too. Yeah,
31:26
Speaker 1: there could be a right handed horgy and doing a
31:28
Speaker 1: right handed podcast right now, doing it the right way
31:33
Speaker 1: we left, and we'd feel left out exactly. Wow. Alright, So, um,
31:41
Speaker 1: I guess my question is like, why why wouldn't our
31:45
Speaker 1: week fource with the left handed bias interact with the
31:51
Speaker 1: left handed mirror matter? Do you know what I mean? Like, like,
31:55
Speaker 1: if in my house I only like my left handed kids,
31:58
Speaker 1: wouldn't I like the right handed kids in the other house. Well,
32:03
Speaker 1: first of all, I hope that either all your kids
32:05
Speaker 1: are left handed or they don't listen to this podcast. Um,
32:09
Speaker 1: but you're right, but our forces don't interact with those
32:11
Speaker 1: particles at all. So those particles don't carry like electric charge,
32:16
Speaker 1: they carry mirror electric charge, and they interact with like
32:19
Speaker 1: the mirror photon, with mirror electromagnetism. And so yeah, you
32:24
Speaker 1: might ask, like, why do you need to create all this,
32:26
Speaker 1: all these particles, Why don't you just add a right
32:28
Speaker 1: handed neutrino. And I think that's one of the biggest
32:30
Speaker 1: sort of theoretical criticisms of this idea is that it's
32:33
Speaker 1: too much. You don't need all this extra stuff. It
32:36
Speaker 1: just seems like too much of a copy. But the
32:39
Speaker 1: reason to do it, remember, is to try to restore symmetries,
32:42
Speaker 1: to try to say, well, let's have balance in the universe.
32:45
Speaker 1: And and then you might ask, but you know, we're
32:47
Speaker 1: not really balanced. We have like two pieces cracked in
32:50
Speaker 1: half that sort of compliment each other, but we're living
32:53
Speaker 1: on one half of it, right, It's not like the
32:55
Speaker 1: universe has this symmetry sort of broken, and we see
32:58
Speaker 1: that a lot in particles ZIX that we see symmetries
33:01
Speaker 1: that have been broken, and we think that these symmetries
33:04
Speaker 1: are fundamental, that they like existed in the early parts
33:07
Speaker 1: of the universe when everything was hotter, when the universe,
33:11
Speaker 1: when different effective laws of physics were taking place, and
33:14
Speaker 1: then as the universe cooled, just sort of like cracked
33:16
Speaker 1: the way you know ice can crack as it freezes,
33:19
Speaker 1: or where things can crack as a change phase, or
33:22
Speaker 1: like we we everything felt to one side of the
33:24
Speaker 1: mirror kind of or got trapped inside. Yeah, and we
33:27
Speaker 1: ended up trapped in one side of the mirror, and
33:29
Speaker 1: that there's other particles that got trapped on the other side.
33:32
Speaker 1: And so these are what we call broken symmetries. We
33:34
Speaker 1: think that they do reflect something deep that's happening in
33:37
Speaker 1: the universe, but that they got broken, and we actually
33:40
Speaker 1: see examples of those, like the Higgs boson is a
33:42
Speaker 1: broken symmetry. Like the Higgs boson unifies the weak force
33:47
Speaker 1: and electromagnetism, and it says that the photon is actually
33:51
Speaker 1: part of the electroweak force. It should go along with
33:54
Speaker 1: the W bosons and the Z boson, But when the
33:58
Speaker 1: universe was cooling, the Higgs sort of stuck in a
34:00
Speaker 1: weird spot, and it gave all this mass to the
34:02
Speaker 1: w n Z and none to the photon. It broke
34:05
Speaker 1: that symmetry. And so in the same way symmetry is
34:08
Speaker 1: that existed in the early hot universe can be broken
34:11
Speaker 1: as a sort of the phase of the universe changes,
34:13
Speaker 1: you know, universites and go from like liquid to gas.
34:16
Speaker 1: But as it cools, different physics sort of takes over,
34:19
Speaker 1: and so we think that that might have broken. So
34:22
Speaker 1: that's another explanation for the asymmetry. That wouldn't require this
34:26
Speaker 1: whole new universe sitting on top of us that we
34:28
Speaker 1: can't see her touch. That would explain why this symmetry exists.
34:32
Speaker 1: Sort of at a higher level, it's like, you know, yeah,
34:35
Speaker 1: we still have an asymmetry here today, but we think
34:37
Speaker 1: that maybe there was a symmetry early in the universe,
34:40
Speaker 1: that that the other half exists, that it explains why
34:43
Speaker 1: the symmetry was broken at some point. All right, So, um,
34:46
Speaker 1: it sounds like a pretty amazing and incredible concept. I
34:50
Speaker 1: guess the question now is how do we verify if
34:53
Speaker 1: it's true? How how do we know it's real? And
34:55
Speaker 1: how do we look for these mirror particles? I guess
34:58
Speaker 1: we can't just look in the mirror. Then, Oh my god,
35:01
Speaker 1: nobody thought of that. I'm gonna do that right now,
35:03
Speaker 1: Hold on, Nobel prize right here, mirror? What's the noble
35:09
Speaker 1: mirror of Nobel Prize? Is the Lobel Prize? Literally? Yeah,
35:14
Speaker 1: do you have to pay a million dollars for that one?
35:18
Speaker 1: That's why nobody accepts it. All right, let's get into
35:21
Speaker 1: how we look for a mirror matter, But first let's
35:23
Speaker 1: take a quick break. All right, Daniel, sir, there might
35:39
Speaker 1: be a whole mirror universe of mirror electrons and quarks
35:45
Speaker 1: and particles and also forces. There might be a whole
35:49
Speaker 1: universe of mirror forces, like the opposite electromagnetic force and
35:54
Speaker 1: opposite strong force sitting right on top of us right now,
35:58
Speaker 1: acting and ignoring us. But yeah, and they might even
36:01
Speaker 1: have like better snacks than we have. Yeah, all the
36:05
Speaker 1: bananas would be um curve the other way. They would
36:09
Speaker 1: actually be tasty. But you would still hate it though,
36:14
Speaker 1: probably would hate it. Yeah, all right, I guess that
36:17
Speaker 1: the question is how do we look for a mirror
36:19
Speaker 1: matter if it does exist? And how could we ever,
36:22
Speaker 1: you know, confirm the existence is something we can't see
36:25
Speaker 1: or touch? It's pretty tough. In the sort of cleanest
36:29
Speaker 1: version of the idea, we can only interact with mirror
36:32
Speaker 1: matter through gravity, and so in that sense, we can
36:35
Speaker 1: only look for its effects on a gravitational scale, which
36:38
Speaker 1: means like looking for it the way we look for
36:41
Speaker 1: dark matter, because gravity is kind of like the the
36:44
Speaker 1: one thing in common we have with mirror matter, Like
36:47
Speaker 1: it's it's like a two vent diagrams that touch at
36:50
Speaker 1: a point. Yeah, it's the only way that we can
36:52
Speaker 1: interact with it, And so to discover something, to prove
36:55
Speaker 1: that it exists, to understand it, we need to be
36:57
Speaker 1: able to interact with it. There could be all sorts
37:00
Speaker 1: crazy stuff happening right here on top of us, but
37:02
Speaker 1: if it doesn't interact with us, then we could never
37:04
Speaker 1: discover it. But we think that gravity is sort of universal.
37:07
Speaker 1: Everything that has mass feels gravity. That's like another way
37:11
Speaker 1: that gravity is super weird and amazing. But so we
37:14
Speaker 1: might have to just use gravity to study it. And
37:16
Speaker 1: then there's the natural question of like, well, if there's
37:19
Speaker 1: all this weird stuff out there that we can't see
37:22
Speaker 1: and gives us extra gravity, maybe it's not like dark matter.
37:25
Speaker 1: Maybe it is dark matter that's what I was about
37:28
Speaker 1: to ask Daniel. It feels like the perfect conspiracy theory
37:32
Speaker 1: bom bom bomb. But this guy in Australia has cracked.
37:35
Speaker 1: O Um. People always right in and try to connect
37:39
Speaker 1: the mystery of dark matter with other mysteries. You know,
37:41
Speaker 1: is dark matter like antimatter? Is dark matter? This is
37:45
Speaker 1: dark matter that? And it's super fun. It's fascinating because
37:48
Speaker 1: wouldn't it be awesome to like crack two mysteries simultaneously, right,
37:52
Speaker 1: to solve two big questions of physics at once. This
37:55
Speaker 1: seems really tantalizing, right because you just told me that
37:58
Speaker 1: there might be a whole universe of matter out there
38:02
Speaker 1: that we can't see a touch, but that influences us gravitationally.
38:05
Speaker 1: Then that that sounds like exactly like dark matter. Yeah, Well,
38:08
Speaker 1: do you want the good news first or the bad news?
38:11
Speaker 1: I want? I want the news that gives me the
38:13
Speaker 1: Nobel Prize. Okay, well, then here's the good news, and
38:17
Speaker 1: you should go off on your trip to get the
38:18
Speaker 1: new prize before you hear the bad news. In this case,
38:22
Speaker 1: the good news is that you can use dark matter
38:24
Speaker 1: detectors to look for this kind of stuff, and that
38:26
Speaker 1: there is a detector out there. It's called the DAMA experiment.
38:30
Speaker 1: It's in Italy, and it's actually had a very strong
38:33
Speaker 1: signal for dark matter for like more than ten years.
38:36
Speaker 1: We're gonna do a whole episode on why nobody believes
38:39
Speaker 1: that DAMA detected dark matter despite their amazing evidence for
38:42
Speaker 1: a dark matter and nobody's been believing their signal. They
38:46
Speaker 1: have this very clear signal that looks like it should
38:48
Speaker 1: be dark matter, but nobody else sees it, like other
38:51
Speaker 1: dark matter experiments don't see the same thing and they should.
38:54
Speaker 1: But this guy in Australia has this explanation. He's like, oh, well,
38:57
Speaker 1: maybe that's because um, those dark other dark matter experiments
39:02
Speaker 1: are only sensitive to heavier versions of mirror matter, and
39:06
Speaker 1: this one experiment in Italy is different from all the
39:08
Speaker 1: other ways in such a way that makes it sensitive
39:11
Speaker 1: to mirror matter. So he thinks that this Dama experiment
39:15
Speaker 1: might actually be a signal of dark matter and a
39:18
Speaker 1: signal that dark matter is mirror matter. Is this one
39:22
Speaker 1: of the ones that that you know has has like
39:24
Speaker 1: a huge vat of some noble gas sitting around waiting
39:27
Speaker 1: for things to ping ping it. Yeah, it's sort of
39:29
Speaker 1: similar it's a slightly different setup, which is why it's
39:32
Speaker 1: a little bit different, and we'll dig into the details
39:35
Speaker 1: on another episode. But they have this signature that most
39:38
Speaker 1: of the people in the community think probably isn't dark matter,
39:41
Speaker 1: but you know, they believe it, and their experiment is
39:44
Speaker 1: different from other experiments, and so they try to find
39:47
Speaker 1: like a reason why only they would see this thing
39:49
Speaker 1: that other experiments don't see, and they're saying it could
39:52
Speaker 1: also be mirror matter, meaning that they're both the same thing. Yeah,
39:55
Speaker 1: and so Bob Foot in Australia he wrote this paper saying,
39:58
Speaker 1: ha ha, maybe this ex planes why Dama is seeing
40:01
Speaker 1: this weird signal and it's a discovery of mirror matter.
40:04
Speaker 1: So that was pretty exciting for a few minutes. But
40:11
Speaker 1: but somebody found an error. Well, it's a little bit
40:14
Speaker 1: unlikely because we know that dark matter, if it exists,
40:17
Speaker 1: is cold, right, it's not fast moving. It tends to
40:21
Speaker 1: poke around the universe, it doesn't zip around, whereas mirror matter,
40:25
Speaker 1: if it's real and it really is a mirror of
40:27
Speaker 1: everything we know, should have similar properties to our matter.
40:31
Speaker 1: It should there should be relativistic elements of it. And
40:34
Speaker 1: so already we think like, well, mirror matter doesn't really
40:37
Speaker 1: fit the same profile of dark matter. What we know
40:39
Speaker 1: about dark matter doesn't really mimic everything we know about
40:42
Speaker 1: the standard model. It seems like it should be heavier
40:45
Speaker 1: and slower. Mirror matter is too hot for dark matter.
40:48
Speaker 1: That's right, exactly. Everybody looks better in the mirror, right,
40:53
Speaker 1: everyone looks hotter. Yeah. Well, but I guess, um, I mean,
40:56
Speaker 1: are you saying that dark matter is significantly colder in
41:00
Speaker 1: general than we are? Yes, m absolutely, you know, I see. Yeah.
41:06
Speaker 1: And then the other thing is that that was fifteen
41:09
Speaker 1: years ago, and since then there has been a lot
41:11
Speaker 1: more experiments looking for dark matter and cross checking the
41:14
Speaker 1: DAMA experiment, And if mirror matter was making a signal
41:18
Speaker 1: in the DAMA experiment, we would have seen it in
41:20
Speaker 1: some of these other experiments c d M S and xenon.
41:23
Speaker 1: And it's not as special anymore. Yeah. So there was
41:26
Speaker 1: a brief window, you know, when the experiments looked like
41:29
Speaker 1: they might support this crazy idea, and that was exciting
41:32
Speaker 1: for a few minutes, but it sort of fell apart,
41:34
Speaker 1: all right. So, um, not a lot of support experimentally
41:38
Speaker 1: for this idea. Are there any other ways that we
41:40
Speaker 1: could find mirror matter. Well, the other things we could
41:44
Speaker 1: do gravitationally are trying to look for its effects, you know, astronomically,
41:49
Speaker 1: because it might be that mirror matter isn't like diffused
41:52
Speaker 1: and spread out the way dark matter is. It really
41:54
Speaker 1: does have interactions that can form interesting structures, like there
41:58
Speaker 1: could be mirror stars out there, or there could be
42:00
Speaker 1: mirror galaxies and mirror planets, right, and so that could
42:03
Speaker 1: be exciting. Would we be able to see them Do
42:06
Speaker 1: they still spit out you know, photons or do they
42:09
Speaker 1: spit out mirror photo They spit out mirror photons only
42:12
Speaker 1: for the mirror astronomers to write mirror papers about and
42:14
Speaker 1: win mirror Nobel prizes. Um. But of course we might
42:18
Speaker 1: be able to see their effects gravitationally. But you know,
42:21
Speaker 1: these are not studies where you're like looking for individual
42:24
Speaker 1: particles of mirror matter, but you're like looking forward distortions
42:27
Speaker 1: in cosmic gravitational fields. You know, we talked on the
42:31
Speaker 1: podcast before about weird gravitational anomalies in the universe, like
42:34
Speaker 1: the Great Attractor, a strange source of localized gravity somewhere
42:39
Speaker 1: beyond the Milky Way that we can't explain in terms
42:42
Speaker 1: of the stuff that we see. So that's the kind
42:45
Speaker 1: of thing that you might try to explain using like
42:48
Speaker 1: mirror galaxies. Oh but I guess at the mirror at
42:52
Speaker 1: the galaxy level, it's sort of maybe indistinguishable from dark matter, maybe,
42:57
Speaker 1: except that dark matter tends to clump with normal matter.
43:01
Speaker 1: Dark matter normal matter tend to overlay each other. In fact,
43:04
Speaker 1: the reason you have normal matter where it is is
43:06
Speaker 1: because there's dark matter. They're like pulling it together. So
43:09
Speaker 1: then are you saying that there could be a mirror planet,
43:12
Speaker 1: like right now in our Solar system spinner around our sun.
43:18
Speaker 1: We just can't see it, but we might feel it gravitationally.
43:21
Speaker 1: Is that kind of the idea. That's kind of the idea.
43:22
Speaker 1: I mean, I never thought about in terms of like
43:24
Speaker 1: a whole mirror planet in our solar system. That's pretty awesome,
43:27
Speaker 1: And I'm right now writing that down for an idea
43:29
Speaker 1: for a science fiction novel, which somebody should write. That's
43:33
Speaker 1: pretty cool. I was more thinking about like entire mirror
43:36
Speaker 1: galaxies separated from ours. But no, you're right. I mean,
43:38
Speaker 1: if our matter feels gravity, it could pull on this stuff,
43:41
Speaker 1: and so our son could have a mirror planet surrounding it,
43:44
Speaker 1: And in fact, Bob Foote from Melbourne claims that some
43:48
Speaker 1: weird things in the Solar system support the existence of
43:52
Speaker 1: mirror matter. H like that there could be mirror asteroids
43:55
Speaker 1: kind of in in the in how all of the
43:59
Speaker 1: things in our solar system move around. Yeah, and he's
44:01
Speaker 1: looked at some like craters on some things in the
44:04
Speaker 1: Solar system and claimed that they can't be explained using
44:08
Speaker 1: normal impacts from normal asteroids. You would need a mirror
44:11
Speaker 1: asteroid to explain it. And I'm pretty spectical and glass everywhere,
44:15
Speaker 1: and you're like, like, it has to be a mirror collision.
44:19
Speaker 1: I'm pretty skeptical of that because you know, mirror objects
44:23
Speaker 1: wouldn't collide with normal objects the normal way, right, They
44:26
Speaker 1: don't feel electromagnetism or the strong force, so they would
44:29
Speaker 1: mostly just pass through each other and affect each other
44:31
Speaker 1: just gravitationally, So you can't really have like impact sites
44:35
Speaker 1: or collisions in that same way. You can only feel
44:37
Speaker 1: a gravitational tug. So that would be pretty spectacular. But
44:41
Speaker 1: I'm not sure I buy that argument all right, But
44:43
Speaker 1: it sounds like a pretty interesting idea, and again, I
44:46
Speaker 1: think it really taps into against the whole feeling that
44:49
Speaker 1: maybe there's a whole universe out there that's kind of
44:53
Speaker 1: on top of us but maybe unreachable. You know, all
44:55
Speaker 1: these ideas are fascinating for that reason, and this idea
44:58
Speaker 1: may be wrong or maybe right, but it's definitely true
45:02
Speaker 1: that there is stuff out there that we don't understand,
45:04
Speaker 1: that there's a whole invisible universe of stuff going on
45:07
Speaker 1: that if we could tap into it and figure it out,
45:09
Speaker 1: would give us a sense of context, you know, like
45:12
Speaker 1: where which part of the puzzle are we in. It's
45:14
Speaker 1: like when you're doing a puzzle and you're just working
45:16
Speaker 1: on a time a little bit and you don't even
45:17
Speaker 1: really know, like where does this go? Is this part
45:19
Speaker 1: of that foot, there's this part of the person's face.
45:21
Speaker 1: That's where we are in physics. We have no idea
45:23
Speaker 1: where our little piece fits in. We know that the
45:26
Speaker 1: puzzle is huge and we've only tapped into a little
45:29
Speaker 1: bit of it, and so this is temptation will be like, well,
45:31
Speaker 1: maybe this fits on over here, maybe this is other
45:33
Speaker 1: part over there. And so it's definitely a good idea
45:36
Speaker 1: to look for weirdnesses and what we see and try
45:39
Speaker 1: to reflect it into the larger context. I think that's
45:42
Speaker 1: definitely a good way forward. I'm not sure about this
45:44
Speaker 1: particular theory, but you know, I'm definitely a fan of
45:47
Speaker 1: this kind of idea. I like what you did there, Daniel,
45:50
Speaker 1: he said, reflected. I reflected on that joke for a while.
45:56
Speaker 1: All Right, well, m hopefully that will get everyone to
46:00
Speaker 1: think a little bit about all of these amazing symmetries
46:02
Speaker 1: we have and and all of the amazing asymmetries that
46:05
Speaker 1: we have in our universe, because you know, there has
46:07
Speaker 1: to be kind of a reason for these weird, unexplained
46:11
Speaker 1: patterns in our universe. That's right, and anybody out there
46:15
Speaker 1: could be the person who figures it out. We joke
46:18
Speaker 1: around a little bit about how this just one guy
46:19
Speaker 1: in Australia, but you know, it only takes one person
46:22
Speaker 1: to have an idea and to change the world, and
46:25
Speaker 1: for that to be correct. Einstein was just one guy,
46:29
Speaker 1: you know, Maxwell was just one guy. All these people
46:31
Speaker 1: who contributed to science, they had an idea and they
46:34
Speaker 1: propagated it forward. And so that could be bob Foot
46:37
Speaker 1: in Australia, or it could be you, or it could
46:39
Speaker 1: be your kids. So everybody out there should be thinking
46:41
Speaker 1: deeply about the universe and trying to understand the whole
46:44
Speaker 1: context of our lives. Yeah, so all of you thinking
46:48
Speaker 1: about physics, look in the mirror and raise your right
46:51
Speaker 1: hand or your left hand and help us figure all
46:55
Speaker 1: this stuff out. Well, we hope you enjoyed that. Thanks
46:57
Speaker 1: for joining us, See you next time. Thanks for listening,
47:09
Speaker 1: and remember that Daniel and Jorge Explain the Universe is
47:12
Speaker 1: a production at I Heart Radio or more podcast for
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Speaker 1: my heart Radio, visit the I Heart Radio Apple Apple Podcasts,
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Speaker 1: or wherever you listen to your favorite shows. H