Latest / Daniel and Kelly’s Extraordinary Universe / What's the problem with the Standard Model?

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What's the problem with the Standard Model? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, are you guys done with physics yet? Done
0:11
Speaker 1: with physics? I mean we're just getting started. Yeah, But
0:13
Speaker 1: then you build that large hattern collider. Didn't that answer
0:16
Speaker 1: all of your questions? Now there's always more stuff to
0:18
Speaker 1: figure out? Man, What do you mean people paid ten
0:20
Speaker 1: billion dollars for that and now you need more money.
0:23
Speaker 1: That was just like the down payment on the project.
0:26
Speaker 1: What was that a defined print? We missed that. Somehow
0:30
Speaker 1: research is exploration. Man, They're never any guarantees about what
0:33
Speaker 1: we're going to find. But I thought the Higgs Boson
0:36
Speaker 1: completed the standard model. I mean it's called the standard model.
0:40
Speaker 1: Aren't you done? It's the standard model. Now we want
0:42
Speaker 1: to upgrade it to like the super standard model. Sounds
0:45
Speaker 1: like you need to go work for Apple. It sounds
0:46
Speaker 1: like we should work for f t X. Sounds like
0:48
Speaker 1: we paid you ten billion dollars for the wrong model.
0:52
Speaker 1: Can we have a hundred billion please? Hi am more
1:09
Speaker 1: hammered cartoonist and the creator of PhD comics. Hi. I'm Daniel.
1:13
Speaker 1: I'm a particle physicist and a professor at U C Irvine,
1:16
Speaker 1: and I will never be done asking questions about the
1:19
Speaker 1: nature of reality. But what if you get the final answer,
1:21
Speaker 1: wouldn't you be done? Well? The lesson from that book
1:24
Speaker 1: is that you're never done that even if you do
1:27
Speaker 1: get the final answer. The next question is, well, why
1:29
Speaker 1: this answer and not something else? Why do we live
1:32
Speaker 1: in a universe where the answer is forty two and
1:34
Speaker 1: not forty seven? What does it mean anyway? The questions multiply.
1:39
Speaker 1: Maybe the ultimate answer is because that's a non answer.
1:42
Speaker 1: It's an answer, it's not a very satisfying answer, and
1:46
Speaker 1: in the end we're looking for explanations, not nonsense. But
1:50
Speaker 1: welcome to our podcast. Daniel and Jorge Explained the Universe,
1:53
Speaker 1: a production of I Heart Radio, in which we try
1:55
Speaker 1: to satisfy your curiosity about the nature of the universe.
1:59
Speaker 1: Why is the world made up of tiny little particles
2:02
Speaker 1: frothing together to build up our reality? How far down
2:06
Speaker 1: do you have to go before you can really understand
2:08
Speaker 1: the universe at its most basic level? And is there
2:11
Speaker 1: even a most basic level? Or is there an infinite
2:14
Speaker 1: tower of questions all the way from galaxies down to
2:18
Speaker 1: black holes, down to particles, down to strings, and then
2:22
Speaker 1: down to whatever strings are made of. Yeah, it's an
2:25
Speaker 1: incredible universe full of gigantic phenomenon like black holes and
2:29
Speaker 1: galaxies and clusters of galaxies, but also with a lot
2:32
Speaker 1: going on at the microscopic level, with atoms and particles
2:36
Speaker 1: and tiny little quantum lips, and somehow it also needs
2:38
Speaker 1: to be ruled by the same rules. The same rules
2:41
Speaker 1: supplies from the tiniest levels to the most cosmic of
2:44
Speaker 1: all levels. It really is incredible how many layers of
2:48
Speaker 1: zoom we have for the universe. Like we can think
2:51
Speaker 1: about the universe on the scale of super clusters of galaxies,
2:55
Speaker 1: objects that are hundreds of millions of light years across,
2:58
Speaker 1: and they follow gravity. We can make predictions about how
3:01
Speaker 1: they swirl around each other, and then you can sort
3:03
Speaker 1: of adjust your zoom knob and think about planets and stars,
3:07
Speaker 1: and you can adjust your zoom knob again and think
3:09
Speaker 1: about rocks and liquids, and you can do it again,
3:12
Speaker 1: and think about atoms, and you can do it again.
3:13
Speaker 1: You can think about protons. You can do it again
3:16
Speaker 1: and think about corks. And we just don't know how
3:18
Speaker 1: many layers of zoom are there, and we don't actually
3:21
Speaker 1: even know the answer to the question of whether they
3:23
Speaker 1: all follow the same rules. You know, our reductionist approach
3:26
Speaker 1: assumes that there is a basic nature to the universe
3:29
Speaker 1: with a certain set of laws from which everything else emerges.
3:33
Speaker 1: But that's sort of a philosophical assumption. We're not even
3:36
Speaker 1: sure that's true. Do you find yourself, Daniel, reading a
3:39
Speaker 1: scientific paper that you print it out on paper and
3:41
Speaker 1: then you're trying to zoom in with your fingers? Does
3:44
Speaker 1: that work? I do sometimes click on blue links on
3:47
Speaker 1: printed out papers, and I'm frustrated that they don't just
3:50
Speaker 1: like print out the right paper for me. That would
3:52
Speaker 1: be awesome if you could click on a link on
3:53
Speaker 1: a paper and your printer would just print the next paper.
3:56
Speaker 1: But it is pretty amazing that we know so much
3:58
Speaker 1: about the universe, from the neest levels to the largest
4:01
Speaker 1: of all stages the entire universe. And I guess the hypothesis,
4:05
Speaker 1: like you said, it, is that there's one set of
4:07
Speaker 1: rules that somehow rules at all. That's certainly one philosophical approach.
4:11
Speaker 1: We call that reductionism, the idea that the tiny dominates
4:14
Speaker 1: the huge. And it sort of makes sense to us
4:17
Speaker 1: intuitively that things emerge from the smallest bits, But if
4:20
Speaker 1: you dig down into it, there's not really a whole
4:22
Speaker 1: lot of justification for it. I mean, why should the
4:25
Speaker 1: small dominate the large? Why can't rules emerge at the
4:29
Speaker 1: larger levels as well and dominate the small? Wait? Who
4:32
Speaker 1: said the tiny dominate the large? I would say that
4:35
Speaker 1: the particles here on Earth pretty much subject to whatever
4:38
Speaker 1: the Sun wants to do. I think the sort of
4:39
Speaker 1: standard philosophical approach to physics is to imagine that there
4:43
Speaker 1: are basic rules at the smallest scale, and those rules
4:46
Speaker 1: somehow weave themselves together to make our reality. And so
4:49
Speaker 1: in order to understand the basic nature of the universe,
4:51
Speaker 1: we should dig deep into the smallest particles to try
4:54
Speaker 1: to find the smallest of the smallest of the small,
4:57
Speaker 1: and a long way we have made a lot of progress,
4:59
Speaker 1: a lot of encouraging results. We've understood the nature of
5:02
Speaker 1: the periodic table based on how protons and neutrons and
5:04
Speaker 1: electrons fit together to make all of those different atoms.
5:08
Speaker 1: We've even understood how protons and neutrons are built out
5:11
Speaker 1: of smaller pieces. So there are a lot of hints
5:13
Speaker 1: that suggest that we should keep digging down into the
5:16
Speaker 1: nature of reality to understand how the bigger things emerge.
5:20
Speaker 1: It's kind of interesting how physics has some I've covered
5:23
Speaker 1: both ends of the spectrum, but not the stuff in between.
5:26
Speaker 1: Like you start on small with the particles and atoms,
5:29
Speaker 1: but then that's when you're like, ah, that's chemistry, and
5:31
Speaker 1: after that biology, and after that you know, political science.
5:35
Speaker 1: We don't care about that. But then once you get
5:37
Speaker 1: to like the size of the planet of the Solar System,
5:39
Speaker 1: and you're like, Okay, now I'm back. Now I'm interested
5:42
Speaker 1: in this again as a physicist will take over from
5:45
Speaker 1: here until the end of the universe. Yeah, that's right.
5:48
Speaker 1: And it's really fascinating sort of from a sociological point
5:51
Speaker 1: of view, because for a long time, those communities, the
5:54
Speaker 1: astrophysics community and the particle physics community were totally separate.
5:58
Speaker 1: The people who worked on galaxies didn't they spent a
6:00
Speaker 1: whole lot of time talking to the people who build
6:02
Speaker 1: colliders and smashed particles together. Though they were in the
6:05
Speaker 1: same department, they didn't really overlap very much. But more
6:08
Speaker 1: recently those communities have come together because there is a
6:11
Speaker 1: common mystery, for example, the mystery of dark matter. We
6:14
Speaker 1: discovered it through astronomical observations that revealed that there's stuff
6:18
Speaker 1: out there that is not made of our kinds of particles,
6:21
Speaker 1: and now we have particle physicists searching for that dark matter.
6:24
Speaker 1: So now we have a new kind of physicist, astro
6:27
Speaker 1: particle physicists that work both on the biggest things and
6:31
Speaker 1: the tiniest things in the universe. But you're right, skipping
6:34
Speaker 1: everything in between. Yeah, I feel like you guys skip
6:36
Speaker 1: over anything that's messy and complicated. I wonder if that
6:39
Speaker 1: says something about your personalities. I do think that I
6:43
Speaker 1: got into physics to avoid all the complications of chemistry
6:46
Speaker 1: and biology. That's certainly true. We like approximating things as
6:51
Speaker 1: simple objects, dots, spheres, circles whenever we can. Planets, right,
6:55
Speaker 1: Planets are also just circles to you. So sons right,
6:58
Speaker 1: basic kindergarten, She's as long as you stick with that
7:01
Speaker 1: than your physicist. I think kindergarten is probably too advanced.
7:03
Speaker 1: I mean, I wouldn't want a triangle shaped planet or anything.
7:06
Speaker 1: Wouldn't that be interesting though, I'd be like that sounds
7:08
Speaker 1: like chemistry to me. I'll focus on the spears. It
7:11
Speaker 1: sounds like geometry. Forget about it exactly. We do have
7:14
Speaker 1: a pretty interesting view of the universe now, and an
7:17
Speaker 1: interesting model that describes how things work at the tiniest
7:20
Speaker 1: levels and that we are hoping extends to the largest
7:24
Speaker 1: of levels. But we do have a model about the universe,
7:26
Speaker 1: and we've been building it over centuries. Right. Physics builds
7:30
Speaker 1: our concepts of the universe sort of on these levels. Right.
7:33
Speaker 1: We have like the atomic level where we think about
7:36
Speaker 1: the elements, and then we zoom in and we think
7:38
Speaker 1: about the nucleus, and then we zoom in and we
7:40
Speaker 1: think about the quarks. And at the level of the
7:42
Speaker 1: quarks and the electrons. You're right, we have a very
7:44
Speaker 1: nice picture of all those particles, how they interact, what
7:48
Speaker 1: they do. And that model also explains all the experiments
7:51
Speaker 1: that we can do smashing particles together at very high
7:53
Speaker 1: energies and all sorts of other very detailed, exhaustive experiments.
7:57
Speaker 1: The picture we have of those particles we've been putting
7:59
Speaker 1: together for about a hundred years. It's sort of all
8:02
Speaker 1: clicks together very nicely. Now. Yeah, it's a pretty good
8:04
Speaker 1: theory that describes what we can see and it works
8:07
Speaker 1: pretty well. However, we sort of know it's not the
8:10
Speaker 1: final theory or the ultimate theory of the universe. That's right.
8:14
Speaker 1: Physics is never done asking questions. And even if we
8:18
Speaker 1: have a beautiful concept which clicks together and explains experiments,
8:22
Speaker 1: this is will always come up with ways to keep
8:24
Speaker 1: the project going. Conveniently, you'll figure out a way to
8:27
Speaker 1: keep your job going. You think being driven by curiosity,
8:31
Speaker 1: staying up late at night wondering about the nature of
8:33
Speaker 1: the universe is convenient. It's almost like an obsession. And
8:37
Speaker 1: so to the end of program, we'll be asking the question,
8:44
Speaker 1: what's the problem with the standard model? I think I
8:48
Speaker 1: know the answer, Daniel, is it me? Am I the problem? Well,
8:51
Speaker 1: that's one problem, yes, But maybe your main problem is
8:54
Speaker 1: that you call it the wrong thing. I mean, you
8:56
Speaker 1: call it the standard model. Not everyone thinks it's the
8:59
Speaker 1: standard one. But now you're saying it's not standard. Yeah,
9:02
Speaker 1: you'll be amazed to discover that we can't even actually
9:04
Speaker 1: agree about what is the standard model. Some people think
9:08
Speaker 1: the standard model is one thing, other people think it's
9:11
Speaker 1: something else. So it turns out the standard is not
9:14
Speaker 1: actually standard. It sounds like you guys have no standards
9:16
Speaker 1: when it comes to naming things, especially models. It doesn't
9:21
Speaker 1: surprise me that we didn't impress you on this one.
9:23
Speaker 1: But really, maybe the question we are asking here today
9:26
Speaker 1: is what are the problems with the standard model? Right,
9:29
Speaker 1: because there's not just one problem with it, there are many.
9:31
Speaker 1: There are many problems, There are unanswered questions, there are
9:34
Speaker 1: cracks in it, there are missing pieces, there are things
9:36
Speaker 1: we know the standard model cannot describe. All of these
9:39
Speaker 1: things are vital hints and clues laying the path for
9:42
Speaker 1: the next generation of physicists, who we hope will reveal
9:46
Speaker 1: a deeper understanding into the nature of reality. So maybe
9:50
Speaker 1: a better name would have been the model issue or
9:53
Speaker 1: the sort of model, the non standard sort of model. Well,
9:57
Speaker 1: usually were wondering how many people have thought about this
9:59
Speaker 1: question and have wondered what are the missing pieces of
10:03
Speaker 1: the standard model? What's wrong with it? So thank you
10:06
Speaker 1: very much to everybody who answers these questions for this
10:09
Speaker 1: segment of the podcast. We thoroughly enjoy hearing your thoughts
10:13
Speaker 1: and we would love for everybody else to have a
10:14
Speaker 1: chance to participate. If you would like to put your
10:17
Speaker 1: voice on the podcast answering these questions, please write to
10:20
Speaker 1: me two questions at Daniel and Jorge dot com. I
10:23
Speaker 1: will set you up. So think about it for a second.
10:25
Speaker 1: What do you think are the problems with the Standard Model.
10:29
Speaker 1: Here's what people had to say. I feel like we're
10:31
Speaker 1: confident about how gravity works, like on the microscope or
10:35
Speaker 1: macroscopic level, and then we're confident about like quantum mechanics,
10:39
Speaker 1: but we don't know how to relate the two. And
10:43
Speaker 1: that's the problem. As I understand that the Standard Model
10:45
Speaker 1: describes a proton and the nucleus and electrons, and the
10:50
Speaker 1: problem with it is that it describes them as little
10:53
Speaker 1: actual points in space as opposed to excitations of various
10:58
Speaker 1: quantum fields. Uh. Therefore, I remember you saying actually in
11:01
Speaker 1: the podcast that it's actually an incorrect interpretation to imagine
11:05
Speaker 1: these little things as particles or a little discrete points
11:08
Speaker 1: in space. Maybe the problem is that it doesn't have
11:12
Speaker 1: anything for the dark matter and dark energy. But my
11:15
Speaker 1: problem is that standard model has many things to remember
11:19
Speaker 1: and it's too difficult for me. I think the main
11:21
Speaker 1: bron with the Standard Model is that there's no room
11:24
Speaker 1: for gravity, and I think, especially with the Higgs, it
11:27
Speaker 1: kind of almost finalized. It snowork kind of stuck. Well.
11:31
Speaker 1: I think that the problem with the Standard Model might
11:34
Speaker 1: be that it is incomplete. It may not have the
11:39
Speaker 1: particles to describe, for example, quantum gravity, so it can
11:44
Speaker 1: be reconciled with general relativity. Well, I think the problem
11:49
Speaker 1: with the standard model is that a people are unsure
11:56
Speaker 1: about the missing pieces in the pattern, missing holes in
12:01
Speaker 1: the periodic table type deal of the standard model. And
12:05
Speaker 1: people are curious if there is on some sort of
12:09
Speaker 1: emergent or if it's some sort of an emergent phenomena
12:13
Speaker 1: of smaller particles, even smaller than those that we observe
12:17
Speaker 1: in the standard model. All right, a lot of awesome
12:20
Speaker 1: ideas here. There seemed to be a lot wrong with
12:23
Speaker 1: the Standard model. I think this might be the first
12:25
Speaker 1: time we can say that every single answer is correct. Wow,
12:29
Speaker 1: that's amazing. So we're done. It turns out the listeners
12:35
Speaker 1: are answering the questions for themselves. We have trained everybody
12:37
Speaker 1: so well that we have worked ourselves out of a podcast. Sorry,
12:41
Speaker 1: we have reached the singularity. Thank you everybody, it's been great.
12:44
Speaker 1: What sounds like maybe you need some different standards or
12:47
Speaker 1: the standard model, you know, like they have the Gold standard,
12:50
Speaker 1: the Platinum Standard, Green Standard, the tin Can Standard. Well,
12:55
Speaker 1: you know, I do think it's a strange name for
12:57
Speaker 1: a theory, The Standard model it's like calling something modern physics.
13:02
Speaker 1: You know, what we teach as modern physics these days
13:04
Speaker 1: is physics as we knew it about a hundred years ago.
13:07
Speaker 1: So when they started calling it modern physics, they sort
13:10
Speaker 1: of painted themselves into a corner. And that happens every
13:13
Speaker 1: time you give something a name like that. It's like
13:16
Speaker 1: calling the draft of your paper final final, ready to submit.
13:20
Speaker 1: You know, that's not the one you're going to submit.
13:22
Speaker 1: It's going to be ready to submit virgin seven before
13:25
Speaker 1: you actually turn that paper in. So then what do
13:27
Speaker 1: you teach at the graduate level? Postmodern physics, deconstructive is physics,
13:33
Speaker 1: impressionist physics. Yeah, now we have avoided giving an updated
13:36
Speaker 1: name like supermodern physics or actually modern physics. We just
13:43
Speaker 1: teach whatever it is we know. Now, well, I guess
13:45
Speaker 1: there's a classical physics, so you've got to figure out
13:47
Speaker 1: how to distinguish it from that, right, Yeah, Well, we
13:49
Speaker 1: usually think about classical physics and quantum physics, and quantum
13:53
Speaker 1: physics obviously more recent than classical physics. What do you
13:57
Speaker 1: call this podcast physics? Light diet physics? No, this is
14:03
Speaker 1: the juice man. This we are squeezing physics to extract
14:06
Speaker 1: all of the core ideas and understanding. This is like
14:09
Speaker 1: a shot of physics. This is like the frozen concentrate
14:14
Speaker 1: kind of physics. This is like that protein powder man.
14:19
Speaker 1: This will beef you up in your physics knowledge. Your
14:24
Speaker 1: brain might not be great for your kidneys, but it
14:26
Speaker 1: will make your mind strong. All right, Well, let's dig
14:28
Speaker 1: into this, Daniel. I guess first of all, what is
14:31
Speaker 1: the standard model and is it really standard? So the
14:33
Speaker 1: standard model is our description of nature at the deepest
14:37
Speaker 1: level that we have seen so far. You know, we
14:40
Speaker 1: have six quarks, we have six leptons, we have forces
14:44
Speaker 1: that tie them all together. The standard model is what
14:46
Speaker 1: we call our theory of how all of that works.
14:49
Speaker 1: And it really has emerged from a piece of work
14:51
Speaker 1: that started like about a hundred and fifty years ago
14:55
Speaker 1: with Maxwell, as he tied together electricity and magnetism into
15:00
Speaker 1: a unified concept of electromagnetism. That was really like the
15:03
Speaker 1: first step towards having any sort of holistic understanding of
15:07
Speaker 1: various phenomena in physics and like one big idea. Right,
15:12
Speaker 1: But then this sort of this was after Newton, right,
15:14
Speaker 1: Like Newton had an idea of how forces and masses
15:17
Speaker 1: and things interacted and worked. This is more about, like,
15:20
Speaker 1: let's break it down and think about all the different
15:22
Speaker 1: kinds of forces that are out there. Yeah, Newton was
15:25
Speaker 1: thinking about how masses move and the effects of gravity,
15:28
Speaker 1: but there are lots of other phenomena out there that
15:31
Speaker 1: can't be explained by gravity, right, like electricity and magnets
15:34
Speaker 1: and all sorts of other stuff. And Maxwell brought a
15:37
Speaker 1: bunch of things together and put them sort of under
15:39
Speaker 1: one umbrella. He developed sort of the standard model of electromagnetism,
15:43
Speaker 1: and that's sort of like the founding kernel of today's
15:46
Speaker 1: standard model. He explained how forces operate in terms of
15:50
Speaker 1: fields and how a bunch of different forces really were
15:53
Speaker 1: part of one bigger picture, right. And he was looking
15:56
Speaker 1: at specifically at electrical things like you said, and magnetic things,
15:59
Speaker 1: but not gravity. But it's still kind of using Newton's
16:03
Speaker 1: equations to think about like, hey, if I put this
16:05
Speaker 1: magnet in this field, how is it going to move
16:08
Speaker 1: and why does it move? Like that? It's Newtonian in
16:10
Speaker 1: the sense of F equals m A. He was calculating
16:12
Speaker 1: the electric force, for example, on an electron, and you
16:15
Speaker 1: can use F equals m A to deduce how the
16:17
Speaker 1: electron accelerates. So it's part of mechanics in that sense,
16:22
Speaker 1: but really he was digging deeper, was wondering just like,
16:24
Speaker 1: what is the source of these forces? Why are there
16:27
Speaker 1: forces in the universe? And can we explain all of
16:30
Speaker 1: them in terms of a single idea rather than having
16:33
Speaker 1: like a long list of different ones. And is that
16:36
Speaker 1: where the name the standard model came in. The Standard
16:39
Speaker 1: Model as a name didn't really appear until much much later,
16:42
Speaker 1: like a hundred years later. So we have electromagnetism from Maxwell,
16:46
Speaker 1: and then that was turned into a quantum theory when
16:48
Speaker 1: we developed quantum mechanics, and it's sort of fine men
16:51
Speaker 1: and a bunch of other folks that turned electromagnetism into
16:54
Speaker 1: a quantum field theory, which is the more modern version
16:57
Speaker 1: of it. That was about the nineteen fifties ish, and
17:00
Speaker 1: he and some other folks won the Nobel Prize for that.
17:02
Speaker 1: So then we had a quantum version of electromagnetism. But
17:05
Speaker 1: we also have these other forces we had, like the
17:07
Speaker 1: weak force, and Steve Weinberg, who won a Nobel prize,
17:11
Speaker 1: figured out how to bring the weak force together with electromagnetism.
17:15
Speaker 1: And that's the first time people really called this sort
17:16
Speaker 1: of the standard model. And he wrote a paper called
17:19
Speaker 1: a Theory of Leptons, which is what brought the weak
17:21
Speaker 1: force together with electromagnetism. And around then is when people
17:24
Speaker 1: started calling it the standard model. I see, I guess
17:28
Speaker 1: what do you mean by the standard model. It's like, hey,
17:31
Speaker 1: we have all these different ways that particles and things
17:34
Speaker 1: can be pushed in, all these different forces that they
17:37
Speaker 1: seem to experience. Can we put all of these forces
17:39
Speaker 1: into like one umbrella or one you know, equation or theory,
17:44
Speaker 1: and we can? And that's kind of standard because it
17:47
Speaker 1: covers everything. Yeah, although of course the standard model doesn't
17:50
Speaker 1: cover everything yet. Right, even the standard model we have
17:53
Speaker 1: today does not describe everything, as we'll dig into in
17:55
Speaker 1: a minute. So we should think of it as like
17:57
Speaker 1: sort of our current best work in progress description of
18:01
Speaker 1: all the particles that we can't explain so far. But
18:04
Speaker 1: it's sort of like, you know, we're all building a
18:06
Speaker 1: barn together. Let's all work on the same project at
18:09
Speaker 1: least and try to put the whole thing together into
18:13
Speaker 1: one edifice. But it's sort of like how far we've gotten.
18:15
Speaker 1: It's like working draft underscore seven. Now, when you say
18:19
Speaker 1: that you're putting all these different forces under one theory,
18:22
Speaker 1: what does that mean. Does that mean that all these
18:23
Speaker 1: forces are somehow related to each other, they somehow interact
18:27
Speaker 1: with each other, or are they separate. It's just it's
18:29
Speaker 1: just about, you know, putting them under the same grouping. Yeah,
18:34
Speaker 1: that's a really great question. I think there's two ideas there.
18:36
Speaker 1: One is putting the forces in the same mathematical language,
18:40
Speaker 1: like can we describe these things in terms of the
18:43
Speaker 1: same basic concepts? And the basic concept we have for
18:46
Speaker 1: the standard model are these fields that fill space and
18:50
Speaker 1: carry information and momentum around. And that's the basis for
18:53
Speaker 1: why electromagnetism can push on things, and why the weak
18:56
Speaker 1: force can push and pull on things, and also why
18:59
Speaker 1: the wrong nuclear force can. So we have a mathematical
19:02
Speaker 1: sort of formula for how that happens. And the Standard
19:05
Speaker 1: model is cool because it puts all these things sort
19:07
Speaker 1: of in the same mathematical language. For those of you
19:10
Speaker 1: who know some physics and math, it means we can
19:12
Speaker 1: describe everything as a quantum field theory just by specifying
19:15
Speaker 1: its lagrangin, just by saying, here's where the fields are
19:19
Speaker 1: here's how they wiggle, and also here's how they talk
19:22
Speaker 1: to each other. That's sort of like the language we've
19:24
Speaker 1: developed for the standard model. But there's another level to it,
19:27
Speaker 1: which is deeper, which is that sometimes we can see
19:30
Speaker 1: symmetries there. We can say, oh, look this piece of
19:32
Speaker 1: the math over here and that piece of the math
19:33
Speaker 1: over there. If you bring them together, they actually clicked
19:36
Speaker 1: together into something simpler. So that's what we've done, for example,
19:39
Speaker 1: with electromagnetism and the weak force, we've combined them into
19:42
Speaker 1: one mathematical structure we called the electroweak force. So sort
19:47
Speaker 1: of two levels to that. One is just writing it
19:49
Speaker 1: in the same language, and the other is noticing patterns
19:52
Speaker 1: and simplifying things by bringing them together. M Because I
19:55
Speaker 1: guess it could have been that that wasn't the case, right,
19:58
Speaker 1: It could have been that, you know, you study electromagnetism,
20:01
Speaker 1: it's like, oh, it works in this way, and there's
20:03
Speaker 1: this math to describe it. Then when you look at
20:05
Speaker 1: how particles pull on each other through a different force,
20:08
Speaker 1: like the strong force or the weak force, you know,
20:10
Speaker 1: you study that and then it turns out that you
20:12
Speaker 1: need a totally different kind of mas for that and
20:14
Speaker 1: the tooth mass are not compatible. That could have been
20:16
Speaker 1: the case. That could have been the case exactly, and
20:18
Speaker 1: in fact, that is the case for gravity. We have
20:21
Speaker 1: no way currently to bring gravity into this mathematical framework.
20:25
Speaker 1: That's one of the problems we'll talk about later. And
20:27
Speaker 1: so it hasn't succeeded in every single case, but it
20:29
Speaker 1: has succeeded for these fundamental forces, the strong force, the
20:33
Speaker 1: weak force, and electromagnetism. All right, so then that's the
20:36
Speaker 1: standard model. It's something that describes all the known forces
20:40
Speaker 1: except gravity, and all of the particles except a whole
20:43
Speaker 1: bunch of parts. You make it sound like such an
20:49
Speaker 1: amazing achievement, but really this is the accumulation of a
20:52
Speaker 1: huge amount of knowledge and effort and ideas by so
20:55
Speaker 1: many smart people over decades. You know. It really does
20:58
Speaker 1: represent an incredible side into the nature of the universe.
21:02
Speaker 1: But of course there's a lot of work left to
21:04
Speaker 1: be done. Yeah, just the story is left. But let's
21:10
Speaker 1: call it the standard model. Anyways. All right, well, let's
21:13
Speaker 1: dig into the problems that we have with this standard model.
21:16
Speaker 1: What are the missing pieces, what are the things it
21:18
Speaker 1: can't describe, and what are the things that may never describe.
21:21
Speaker 1: But first, let's take a quick break. All right, we're
21:36
Speaker 1: having a standard conversation about the standard model, which is
21:39
Speaker 1: to say that the standard model is not so standard.
21:42
Speaker 1: You don't sound very impressed. I am a pressed. Yeah,
21:44
Speaker 1: describing you know, four percent of the universe or less
21:47
Speaker 1: is pretty good achievement. Yea, what great would you give
21:50
Speaker 1: somebody if they got a four percent on their test?
21:53
Speaker 1: You're the professor, Well, why would you give one of
21:56
Speaker 1: your students of the four percent on a physics test? Yeah? Well,
21:59
Speaker 1: you know, I have to say, what's the curve? Think
22:01
Speaker 1: about all the other alien species out there that have
22:03
Speaker 1: been working on physics for the same amount of time,
22:05
Speaker 1: how far have they gotten? And really you've got the
22:07
Speaker 1: greatest on that curve. I see. You're all about lowering
22:10
Speaker 1: your standards. Is that what you're saying. I'm all about calibrating, man, Well,
22:14
Speaker 1: calibrating this case, lower ring or standards. Maybe maybe it
22:19
Speaker 1: could be that alien species out there basically figured it
22:22
Speaker 1: all out in about twenty minutes and we've been struggling
22:25
Speaker 1: with it for hundreds or thousands of years, depending how
22:27
Speaker 1: you count, and we've hardly made any progress. Or maybe
22:30
Speaker 1: there are aliens out there that have been working on
22:32
Speaker 1: these problems for millions of years and having gotten as
22:34
Speaker 1: far as we have, we just don't know. So then
22:36
Speaker 1: what gray would you give us a for effort? I'd
22:40
Speaker 1: have to go with incomplete, but that's gonna look bad
22:42
Speaker 1: at my transcript. Then, Yeah, I don't think anybody should
22:46
Speaker 1: hire us until we have a sensor whether we're good
22:48
Speaker 1: at this or not. Are the human race all right? Well,
22:53
Speaker 1: let's talk about the problems with the standard model, which
22:56
Speaker 1: I guess is the shining achievement of physics. Right. It
22:59
Speaker 1: described most of the forces that we know about, the
23:02
Speaker 1: strong force, the electoral weak force, and it describes most
23:06
Speaker 1: of the particles that we know about, including all of
23:09
Speaker 1: the ones that were made out of it. Yeah, and
23:10
Speaker 1: before we reveal all the chinks in its armor, let's
23:13
Speaker 1: just spend a moment to appreciate it, because it means
23:16
Speaker 1: something kind of cool about the human experience. It means
23:19
Speaker 1: that basically everything you interact with, every event in your life,
23:23
Speaker 1: everything that happens to you, is mostly explainable, Like there
23:27
Speaker 1: isn't really any magic left in your experience of the universe.
23:32
Speaker 1: Every experience you have, we can mostly explain in terms
23:35
Speaker 1: of the fundamental physics that we do so far understand,
23:38
Speaker 1: you know, lightning and stomach aches and all sorts of things.
23:42
Speaker 1: We think we mostly understand the basic physics of that,
23:45
Speaker 1: even if we can't always make it practical. We can't
23:48
Speaker 1: predict the path of hurricanes that we don't think that.
23:50
Speaker 1: There are mysteries in physics that actually affect your everyday life.
23:54
Speaker 1: And that's a new experience for humanity, right, most humans
23:57
Speaker 1: over the years have lived in a world that was
23:59
Speaker 1: fundamentally not understood by them. Yeah, it's pretty amazing what
24:03
Speaker 1: how much we can describe now although we were sort
24:05
Speaker 1: of they're all already kind of like a hundred years ago, right,
24:08
Speaker 1: Like stomach as we could have predicted the hundred years ago.
24:11
Speaker 1: You don't need quantum physics for that. Yeah, I'm not
24:13
Speaker 1: sure if doctors even now understand the stomaching. Maybe I
24:16
Speaker 1: shouldn't give them too much credit. But you know, there
24:19
Speaker 1: were lots of interesting puzzles about the way the world
24:21
Speaker 1: worked and the particles that were out there that we
24:23
Speaker 1: hadn't figured out yet until we brought them together into
24:26
Speaker 1: this picture of the standard model. But now we mostly
24:29
Speaker 1: understand the world that is around us. So as we
24:32
Speaker 1: dig deeper, of course, there are lots of holes and
24:34
Speaker 1: questions that come up. All right, well, let's dig into
24:37
Speaker 1: some of these holes and and missing pieces of the
24:40
Speaker 1: standard model. And let's start with the big one, the
24:42
Speaker 1: heaviest one, the most massive one. Gravity. Gravity really is
24:46
Speaker 1: the most missing piece of the standard model. Like all
24:49
Speaker 1: the forces that we do experience in our everyday life,
24:52
Speaker 1: the strong force, the weak force, electromagnetism, gravity is the
24:55
Speaker 1: one that we cannot describe yet using the Standard Model,
24:58
Speaker 1: which is in the end, a quantum mechanical description of
25:02
Speaker 1: the nature of the universe. But gravity we have a
25:05
Speaker 1: classical theory. We have general relativity, which ignores quantum mechanics
25:09
Speaker 1: and describe spaces a bending place where particles can move smoothly. Yeah.
25:14
Speaker 1: I know we've talked a lot in the on the
25:15
Speaker 1: podcast about the problems with marrying quantum mechanics and gravity.
25:19
Speaker 1: But maybe it gives a sense of why that's so
25:22
Speaker 1: Hardlet like, I can calculate the gravity between the Sun
25:25
Speaker 1: and the Earth. Why can't I calculate the gravity or
25:28
Speaker 1: gravitational force between you know, an electron and a proton. Well,
25:32
Speaker 1: if you knew exactly where the electron and the proton were,
25:35
Speaker 1: then you could calculate them. You know the distance, you
25:37
Speaker 1: know the masses, all that stuff, But you can write
25:40
Speaker 1: it's possible to know the location of a particle. Electrons
25:43
Speaker 1: are quantum objects, right, so they don't always have a
25:46
Speaker 1: specific location. They have like a probability of being here
25:49
Speaker 1: in a probability of being there. And one question about
25:52
Speaker 1: gravity is like, well, how does that work? Is the
25:54
Speaker 1: gravity of the electron also probabilistic, like the space bend
25:58
Speaker 1: a little bit where the electron might be and a
26:00
Speaker 1: little bit somewhere else with the electron might be. The
26:03
Speaker 1: orders gravity collapse the electron's wave function, requiring it to
26:06
Speaker 1: be in one place, so that it sort of it
26:08
Speaker 1: knows how to bend space the right amount and exactly where.
26:11
Speaker 1: I guess. Maybe the question is like, we can calculate
26:14
Speaker 1: the force between an electron and a proton, right, and
26:17
Speaker 1: as I understand it, it involves like exchanging a photon.
26:21
Speaker 1: But when you can calculate that force and what happens
26:24
Speaker 1: to those two particles, why can I do the same
26:26
Speaker 1: with gravity? Think? If I have an electron a proton,
26:29
Speaker 1: why can't I just calculate how much force they put
26:31
Speaker 1: on each other. So if you're thinking about the electromagnetic
26:34
Speaker 1: force between a proton and an electron, you're right. You
26:37
Speaker 1: can calculate that force and you can think about in
26:38
Speaker 1: terms of photons. And that's a quantum mechanical theory that
26:42
Speaker 1: allows the electron to have a probability being here and
26:45
Speaker 1: probability being there. That's all cool because electromagnetism is a
26:48
Speaker 1: quantum theory. It allows all of that. It treats its
26:50
Speaker 1: objects as quantum objects. But gravity, so far is not.
26:54
Speaker 1: Gravity is a classical theory, and in order to know
26:57
Speaker 1: how much space bends, you have to know where something
26:59
Speaker 1: is and you have to know it's trajectory through space
27:01
Speaker 1: and time, and that's not possible for quantum objects. So
27:05
Speaker 1: people have tried what you suggested, like, well, let's build
27:07
Speaker 1: a quantum theory of gravity and think about exchanging little
27:11
Speaker 1: particles for those forces. They call them gravitons, and so
27:14
Speaker 1: people certainly have worked on that. They have tried to
27:16
Speaker 1: add gravity to the standard model to make it a
27:18
Speaker 1: quantum theory. The problem is those calculations don't work, like,
27:22
Speaker 1: we don't know how to do it yet. Gravity is
27:24
Speaker 1: a different kind of force than electromagnetism is it requires
27:28
Speaker 1: a slightly different sort of mathematical construction to describe it,
27:31
Speaker 1: and those constructions sort of fail. When we try to
27:34
Speaker 1: do those calculations, we get crazy numbers, we get infinities
27:37
Speaker 1: and negative infinities. It just sort of hasn't worked out yet.
27:40
Speaker 1: The crucial way that gravity is different is that it
27:43
Speaker 1: couples to itself. Like a photon doesn't feel other photons
27:48
Speaker 1: because photons only feel things that have electric charges and
27:50
Speaker 1: photons don't have electric charges. But gravity feels everything because
27:54
Speaker 1: gravity feels everything with energy, and so it's sort of
27:56
Speaker 1: a much crazier system to try to describe using this
28:00
Speaker 1: onto mechanical apparatus, and so far it just hasn't worked.
28:02
Speaker 1: You mean, like maybe the idea of a graviton itself
28:05
Speaker 1: feels gravity like gravity, graviton has energy, and therefore it
28:09
Speaker 1: also affects the particles through its gravity exactly whereas a
28:13
Speaker 1: photon doesn't feel the electromagnetic force, and so it's just
28:16
Speaker 1: simpler to do those calculations. That doesn't mean it's impossible
28:19
Speaker 1: to have a quantum theory of gravity, just means it's
28:21
Speaker 1: going to need sort of new mathematical tools that we
28:24
Speaker 1: just sort of haven't invented yet. The tools that we
28:26
Speaker 1: have used so far haven't worked. Can you just invent
28:29
Speaker 1: the graviton that doesn't feel its own gravity. You can
28:32
Speaker 1: do that, And that's sort of actually the first step
28:34
Speaker 1: in an approximate theory of gravity, you know, like a
28:36
Speaker 1: perturbative theory. We say, let's try to describe part of
28:39
Speaker 1: gravity and assume that the graviton has negligible effect on
28:43
Speaker 1: the gravitational shape. Why can it have zero effect? Well,
28:46
Speaker 1: that would be inconsistent with what we think about general
28:49
Speaker 1: relativity and how gravity works. General relativity says that space
28:52
Speaker 1: bends in response to energy density, and so if gravitons
28:55
Speaker 1: carry that energy, then they should also bend space. Well,
28:59
Speaker 1: maybe just don't apply general relativity at the quantum level. Yeah,
29:05
Speaker 1: some people are building new theories of gravity. The tricky
29:08
Speaker 1: thing is that we have a lot of measurements of
29:10
Speaker 1: gravity already. So if you develop a new theory of gravity,
29:13
Speaker 1: it has to also describe everything we've observed so far
29:16
Speaker 1: about how planets orbit each other, and about black holes
29:19
Speaker 1: and all these things that happened at the big scale,
29:21
Speaker 1: you know, the scale of planets and stars and galaxies.
29:24
Speaker 1: General relativity is past all of these tests with flying colors.
29:28
Speaker 1: So if you develop a new theory has to reproduce
29:30
Speaker 1: all of those calculations as well, and so far you
29:33
Speaker 1: haven't been able to do that. So far, we haven't
29:35
Speaker 1: been able to do that. All of our mathematical attempts
29:37
Speaker 1: has sort of blown up in our hands. Sounds like
29:40
Speaker 1: a heavy situation there, But let's get to some of
29:42
Speaker 1: the other things missing in the standard model, because some
29:44
Speaker 1: of them are pretty big. For example, the universe is
29:48
Speaker 1: not covered by the Standard model. Yeah, the Standard Model
29:50
Speaker 1: is really good at describing the kind of stuff that
29:53
Speaker 1: we are made out of, atoms and molecules and quirks
29:56
Speaker 1: and leptons and all these kinds of things. But in
29:59
Speaker 1: the law asked a few decades, we've discovered that that's
30:02
Speaker 1: not what most of the universe is made out of.
30:05
Speaker 1: We know that if you take a random chunk of
30:06
Speaker 1: space like a cubic light year, and you ask how
30:09
Speaker 1: much energy is in there, it turns out that the
30:11
Speaker 1: energy devoted to quarks and leptons and all the kind
30:14
Speaker 1: of things that we do understand and they are described
30:16
Speaker 1: by the Standard Model is only about five percent of
30:19
Speaker 1: the energy in that cube, and then another like twenty
30:23
Speaker 1: five percent is due to dark matter. So weird new
30:27
Speaker 1: kind of matter that we know is out there. We
30:29
Speaker 1: can see it's gravity and all sorts of other effects.
30:32
Speaker 1: We just don't know what it is and what kind
30:34
Speaker 1: of particle it's made out of, except that we're sure
30:36
Speaker 1: it's not made of our kinds of particles, or at
30:40
Speaker 1: least we know or we think it's not made out
30:41
Speaker 1: of the particles that are currently tallied up by the
30:44
Speaker 1: Standard Model. It's possible that is, it is made of
30:47
Speaker 1: a particle, a different kind of particle or something that
30:51
Speaker 1: then you could add to the Standard Model. That's right,
30:53
Speaker 1: that would be the new Standard Model, Standard Model Underscore
30:56
Speaker 1: Final or Update version two or whatever. But none of
30:59
Speaker 1: the particles that are only in the Standard Model, the quarks,
31:01
Speaker 1: the electrons and nuance, the towns of new trinos, none
31:04
Speaker 1: of those can explain what dark matter is. And that's
31:07
Speaker 1: a whole, really fascinating topic. People can dig into a
31:10
Speaker 1: bunch of podcast episodes about why isn't dark matter neutrinos
31:14
Speaker 1: or how do we know dark matter is not some
31:15
Speaker 1: weird clump of quarks floating out there or primordial black
31:18
Speaker 1: holes or something like that. But we're pretty sure that
31:21
Speaker 1: dark matter is not made out of anything that's currently
31:24
Speaker 1: described in the Standard Model, which means it's something new,
31:27
Speaker 1: something weird, And you're right, if we figured out what
31:29
Speaker 1: that was, we would have to add it to the
31:31
Speaker 1: Standard Model, right. But it could also be the case
31:33
Speaker 1: that maybe dark matter is made out of something that
31:36
Speaker 1: is not described by the mathematics of the Standard Model, right,
31:39
Speaker 1: just like gravity could be something not even compatible with
31:42
Speaker 1: the Standard Model. Absolutely, And it's a sort of extraordinary
31:45
Speaker 1: bit of extrapolation to even assume that it might be right,
31:48
Speaker 1: because we've looked at a tiny fraction of the stuff
31:51
Speaker 1: in the universe, and we developed mathematics that works to
31:53
Speaker 1: describe mostly that, and then we imagine that, oh, maybe
31:57
Speaker 1: the rest of it also, you know, even though we
31:59
Speaker 1: know the rest of it is different and important and
32:01
Speaker 1: fundamental ways from the bit we have studied. So it's
32:04
Speaker 1: sort of a leap to say, maybe we can use
32:06
Speaker 1: the same tools to describe the rest of the universe.
32:09
Speaker 1: Maybe right, but also maybe not. It might be that
32:13
Speaker 1: dark matters not made of particles at all. Their theories,
32:16
Speaker 1: a matter that don't have a sort of scale that
32:18
Speaker 1: as you zoom in, always look the same. Right, These
32:21
Speaker 1: things are called unparticles. There's all sorts of other crazy
32:24
Speaker 1: bonkers ideas that are not particle based dark matter. If
32:27
Speaker 1: you ask me, that's what I would love for us
32:30
Speaker 1: to discover because instead of just like adding a new
32:32
Speaker 1: piece to the standard model and building on quantum field theory,
32:35
Speaker 1: it would point to us a new way that the
32:37
Speaker 1: universe operates, a completely different sort of foundational construct that
32:41
Speaker 1: can describe reality. That would be pretty exciting. But also
32:45
Speaker 1: the standard model doesn't describe dark energy, which is like
32:48
Speaker 1: sixties seven of the universe. Right, two thirds of the
32:50
Speaker 1: universe is also unexplainable by the standard model. Yeah, and
32:54
Speaker 1: when we say two thirds again, we're thinking about a
32:56
Speaker 1: sort of fictional chunk of the universe and accounting for
32:59
Speaker 1: the action of the energy. Right, we don't know how
33:02
Speaker 1: big the universe is, and we say two thirds of
33:04
Speaker 1: the universe, some people might be confused about what are
33:06
Speaker 1: you talking about? The universe is infinite. Two thirds is
33:09
Speaker 1: also infinite. So that's why we think about in terms
33:11
Speaker 1: of energy density, Like take a chunk of the universe
33:14
Speaker 1: and ask how much energy is in that chunk, and
33:16
Speaker 1: how is it apportioned. Well, two thirds of the energy
33:19
Speaker 1: of any chunk of the universe we think is devoted
33:22
Speaker 1: to this thing called dark energy, as you say, And
33:25
Speaker 1: dark energy is just our description of the fact that
33:27
Speaker 1: the universe is expanding, and that expansion is accelerating. That
33:31
Speaker 1: every year, space is getting bigger, and it's getting bigger
33:34
Speaker 1: faster every year, and that requires some energy. And as
33:38
Speaker 1: space gets bigger, it makes new space, and that new
33:41
Speaker 1: space has dark energy in it. And so dark energy
33:44
Speaker 1: is a sort of runaway effect that keeps creating more
33:46
Speaker 1: of itself, which creates more of itself to create more
33:49
Speaker 1: of itself. And so actually the dark energy fraction in
33:52
Speaker 1: the universe is growing. It's now the dominant fraction, and
33:55
Speaker 1: unless something changes, we think it's going to forever dominate
33:58
Speaker 1: our destiny. It seems like maybe the problem with the
34:01
Speaker 1: standard model is that it doesn't talk about space itself right,
34:06
Speaker 1: like it talks about particles and quantum fields, and it
34:09
Speaker 1: assumes a fixed, non changing space. But there's all these
34:12
Speaker 1: other theories like gravity and dark energy and the expansion
34:15
Speaker 1: of the universe that assumes that space itself is changing.
34:18
Speaker 1: Whereas in the Standard model it's it's it's almost like
34:21
Speaker 1: a constant or an assumption. Yeah, I wouldn't say that
34:23
Speaker 1: standard model doesn't talk about space, but you're right, it
34:26
Speaker 1: certainly makes certain very crisp assumptions about space that are
34:30
Speaker 1: in conflict with what we know to be true. Right. Usually,
34:34
Speaker 1: quantum field theory operates on what we call like a
34:36
Speaker 1: flat backdrop. We assume that space exists, and that it
34:39
Speaker 1: always has existed, right, and that it always will exist.
34:43
Speaker 1: The basic way the quantum field theory thinks about space
34:46
Speaker 1: and time is not to think about them together the
34:48
Speaker 1: way relativity does, but to think about them separately. And
34:51
Speaker 1: space is something that exists in time is just how
34:54
Speaker 1: things change in space, and so it thinks about space
34:57
Speaker 1: and time quite separately. And turning there's a equation can
35:00
Speaker 1: describe the universe all the way back infinitely in time
35:03
Speaker 1: and all the way forwards infinitely in time. So quantum
35:06
Speaker 1: field theory is consistent with the universe always having existed
35:09
Speaker 1: and always existing into the future. Whereas when we look
35:12
Speaker 1: at space, as you say, we see that it's changing
35:14
Speaker 1: and that it's expanding, And if you think back far
35:17
Speaker 1: enough in time, it's consistent with some crazy event that
35:20
Speaker 1: we don't understand that might even be the beginning of space.
35:24
Speaker 1: So you're right, there basic questions about the Standard model's
35:26
Speaker 1: treatment of space itself that we don't know how to answer.
35:29
Speaker 1: And that's really connected to this question of general relativity,
35:32
Speaker 1: because general relativity is basically a description of what space is,
35:35
Speaker 1: but we don't know how to unify that with our
35:37
Speaker 1: understanding of quantum mechanics. Is there even a room in
35:40
Speaker 1: the Standard Model for expanding space, Like, is there even
35:43
Speaker 1: a lever you can pull there or a mechanism that
35:46
Speaker 1: allows space to expand In the Standard Model. You can
35:49
Speaker 1: do quantum field theory on curved space or on expanding space,
35:53
Speaker 1: but what we don't know how to do is how
35:55
Speaker 1: to have those fields themselves create that curved space, which
35:59
Speaker 1: is what you sort of need for quantum gravity. So
36:01
Speaker 1: it's possible to do quantum field theory on other funny
36:04
Speaker 1: spaces or other dimensions or expanding spaces, that it gets
36:08
Speaker 1: very very complicated. Can it even then explain the Big Bang?
36:12
Speaker 1: Or not at all? So quantum field theory can't explain
36:14
Speaker 1: the Big Bang as like a singularity, right, Quantum field
36:17
Speaker 1: theory can describe what happens in space after that. But
36:21
Speaker 1: it certainly cannot accommodate a singularity. Quantum mechanics that phoors
36:24
Speaker 1: a singularity, right, because there's a fuzziness to information into
36:28
Speaker 1: the universe. You can zoom everything down into a tiny,
36:31
Speaker 1: dense little dot. You can't even have a singularity at
36:33
Speaker 1: the heart of a black hole according to quantum mechanics.
36:36
Speaker 1: So absolutely not. Our description of quantum field theory is
36:40
Speaker 1: not consistent with a singularity at all. And so that's
36:43
Speaker 1: why when we talk about the Big Bang, we talk
36:45
Speaker 1: all the way back to very very early universe, and
36:47
Speaker 1: we say, well, before that, we need some picture of
36:49
Speaker 1: quantum gravity. Quantum effects and gravitational effects are both important,
36:54
Speaker 1: and we just don't have that theory, and so we
36:55
Speaker 1: don't even know how to think about what happened before
36:58
Speaker 1: that time. Well, sort of sounds like maybe quantum mechanics
37:01
Speaker 1: and the stand model will never maybe even be able
37:04
Speaker 1: to explain why space expanded so fast during the Big Bang, right,
37:07
Speaker 1: why the Big Bang happened at all? Yeah, the standard
37:09
Speaker 1: model as we know it has no explanation for that
37:12
Speaker 1: and may never write if it can handle space expanding
37:15
Speaker 1: or ever explain space expanding. Yeah, well, we imagine that
37:18
Speaker 1: there's some future theory, some quantum theory of gravity, which
37:22
Speaker 1: can explain that. And then when you take the version
37:24
Speaker 1: of that theory and ask what happens when space is
37:27
Speaker 1: mostly flat and mostly cold, then you get the Standard
37:29
Speaker 1: model sort of the same way that, like Newton's theory,
37:32
Speaker 1: is a limiting case of Einstein's theory. Right. Einstein's theory
37:36
Speaker 1: of relativity, we think, is a more accurate description of space.
37:38
Speaker 1: But when gravity is weak and there aren't black holes nearby,
37:41
Speaker 1: it reverts to Newton's theory, right, And so we think
37:44
Speaker 1: that probably quantum gravity is a super version of the
37:46
Speaker 1: Standard model, or the other way around, that the standard
37:48
Speaker 1: model is like a limiting case of some deeper theory
37:52
Speaker 1: of quantum gravity. All right, well, those are the two
37:55
Speaker 1: big gaping holes in the Standard model gravity and also
37:59
Speaker 1: dark matter and dark energy. But the holes don't stop there.
38:03
Speaker 1: There are still other gaps in the Standard Model to
38:06
Speaker 1: bring everything from antimatter to neutrinos. And so let's dig
38:09
Speaker 1: into these mysteries. But first let's take another quick break.
38:25
Speaker 1: All right, we're talking about the I guess it's not
38:27
Speaker 1: so standard model or the standard lead incomplete model the
38:32
Speaker 1: current best theory of physics so far that we're pretty
38:35
Speaker 1: sure is wrong. It needs to be updated asap. That's
38:38
Speaker 1: your standard star. No, it's wrong, but we will press on.
38:44
Speaker 1: Standard really just means work in progress, like every theory
38:47
Speaker 1: in science is always a work in progress. Oh, I
38:50
Speaker 1: see you're using that definition of the word standard, like
38:54
Speaker 1: the current model. It's really just the current model. It's
38:57
Speaker 1: just the latest update Standard Model version six, as downloaded
39:00
Speaker 1: onto your phone last night by Apple. We're still on data,
39:03
Speaker 1: is that what you're saying, or and like we're always
39:07
Speaker 1: beta testing science. All right, Well, as we heard, there
39:10
Speaker 1: are still big things missing about the Standard Model, which
39:13
Speaker 1: is exciting to physicists, And there are some big things missing,
39:16
Speaker 1: but there are also other things that maybe people don't
39:18
Speaker 1: think about are missing from the Standard Model. Even if
39:21
Speaker 1: there weren't questions about dark matter and gravity just zooming
39:24
Speaker 1: in on the particles that we do know about, there
39:26
Speaker 1: are lots of questions that we don't have answers to.
39:29
Speaker 1: So you can look at the Standard Model and you
39:30
Speaker 1: can say, like, why is it this way not some
39:32
Speaker 1: other way? And also does it actually explain everything we see?
39:35
Speaker 1: One of the deepest mysteries that remain in explaining the
39:38
Speaker 1: universe that we have is why it seems to be
39:40
Speaker 1: made of matter and not anti matter. In the Standard Model,
39:44
Speaker 1: we have all the particles we've been talking about, but
39:46
Speaker 1: there's also a shadow particle for every single one. Every
39:49
Speaker 1: quirk has an antiquark, every electron has an anti electron,
39:53
Speaker 1: every tow has an anti tow. There's this beautiful symmetry
39:57
Speaker 1: to all the particles. They have their anti part nticles.
40:00
Speaker 1: And yet when we look out into the universe, we
40:02
Speaker 1: see that I'm made of matter. You're made of matter.
40:05
Speaker 1: Our solar systems made of matter, our galaxies made of matter.
40:08
Speaker 1: We think the nearby galaxies are made of matter. It
40:10
Speaker 1: seems like the universe is basically matter. So if the
40:14
Speaker 1: theory of particles is symmetric, how do we get this
40:17
Speaker 1: asymmetry in our universe? Where does that come from? This
40:21
Speaker 1: sort of the big question. I think what you're saying
40:24
Speaker 1: is that the Standard Model does have antimatter in it right,
40:28
Speaker 1: like anti matter itself. It's not a mystery like that,
40:32
Speaker 1: It's actually part of the Standard Model. Every particle in
40:35
Speaker 1: the model has its antimatter particle. But I think maybe
40:38
Speaker 1: what you're saying is that the model predicts that is,
40:41
Speaker 1: there should be the same amounts of matter and anti matter,
40:43
Speaker 1: right like, according to the theory, there's nothing in it
40:45
Speaker 1: that says, oh, clearly matter is the best matter. Yeah,
40:49
Speaker 1: and there's no reason we call one kind of matter
40:51
Speaker 1: matter the other kind of antimatter except that we are
40:53
Speaker 1: made of one kind, right, There really is no difference
40:56
Speaker 1: between matter and antimatter. No, No, if you're not with us,
40:59
Speaker 1: your anti us. If you're not made of us, you're
41:03
Speaker 1: made of the anti us. Yeah. If you're not, if
41:06
Speaker 1: you're not part of us, you're not us. There you go.
41:08
Speaker 1: If you're not particles of us. Yeah, that's the interesting mystery.
41:13
Speaker 1: And you imagine, for example, the very beginning of the universe.
41:16
Speaker 1: We think probably matter and antimatter were made at the
41:19
Speaker 1: same rates, because why not, Because the theory of particles
41:22
Speaker 1: is basically symmetric with respectum matter and antimatter. There's antimatter
41:26
Speaker 1: quantum fields for every matter quantum field. So then the
41:29
Speaker 1: mystery is, how do you go from a universe that
41:31
Speaker 1: has the same amount of matter and antimatter to our universe,
41:34
Speaker 1: which is almost entirely matter. And that's the unanswered question.
41:38
Speaker 1: We're looking for asymmetries. We're looking for ways the Standard
41:41
Speaker 1: model prefers matter to antimatter, or like processes forces something
41:46
Speaker 1: which produces matter preferentially over antimatter, and we have not
41:50
Speaker 1: explained that yet. Well, there are some hints in the
41:53
Speaker 1: Standard model, right, Like, according to the Standard Model, there
41:55
Speaker 1: is a slight little preference for one kind of matter,
41:58
Speaker 1: isn't there There are some process the seas that do
42:00
Speaker 1: seem to prefer matter to antimatter in the Standard model. Yes,
42:04
Speaker 1: in the Standard Model there are some. Right, it's not
42:07
Speaker 1: perfectly symmetric, but these are pretty small. They're not nearly
42:10
Speaker 1: big enough to explain the asymmetry that we see. It's
42:13
Speaker 1: a hint because it's a crack in the perfect symmetry.
42:15
Speaker 1: It says, maybe the universe prefers matter to antimatter, but
42:19
Speaker 1: the effects that we have discovered cannot explain what we
42:22
Speaker 1: see in the universe. Yet we're missing like a huge
42:25
Speaker 1: chunk of it. Like most of the asymmetry is not explained.
42:29
Speaker 1: But I guess if there was an effect that was
42:31
Speaker 1: so large that it preferred a matter over antimatter to
42:35
Speaker 1: the degree that we see in the universe today, wouldn't
42:38
Speaker 1: they be, you know, kind of a big obvious hole
42:40
Speaker 1: in the theory, or is it possible that what it
42:43
Speaker 1: prefers matter or antimatter is external to the standard model
42:46
Speaker 1: like gravity. Yeah, that's exactly the question. And we're looking
42:49
Speaker 1: for those holes in the theory, and people are doing
42:51
Speaker 1: searches for new processes that prefer matter to antimatter, and
42:55
Speaker 1: recently they have some interesting hints for discoveries at CERN.
42:59
Speaker 1: These are called the flavor anomalies, where like quarks change
43:02
Speaker 1: from one flavor to another, and they tend to do
43:04
Speaker 1: it to matter a little bit more often than antimatter.
43:06
Speaker 1: And people are wondering if this is like the thread
43:09
Speaker 1: we're going to pull on that reveals the universe's preference
43:12
Speaker 1: for matter or antimatter. But nothing is certain yet. But
43:15
Speaker 1: you're also right, it could be something else, something external
43:17
Speaker 1: to the standard model. It could be that the universe
43:20
Speaker 1: wasn't created symmetrically with matter and antimatter at the beginning
43:23
Speaker 1: because of some theory of quantum gravity that prefers matter
43:26
Speaker 1: to antimatter. We just don't know. It's a huge question. Mark. Well,
43:29
Speaker 1: I am pro finding the answer to that. I'm not
43:32
Speaker 1: anti that. Now, what are some of the other things
43:35
Speaker 1: that are missing from the standard model. There are also
43:37
Speaker 1: just a lot of missing explanations for the patterns that
43:39
Speaker 1: we see. Like if you look at the patterns of
43:41
Speaker 1: the particles, you see that there's a four basic particles,
43:44
Speaker 1: the up, the down, and the electron and the neutrino.
43:47
Speaker 1: But each one has two copies, right, The up has
43:50
Speaker 1: the charm and the top, the electron has the muon
43:52
Speaker 1: and the tow And this is sort of nice consistency
43:55
Speaker 1: there where each of the four based particles has exactly
43:58
Speaker 1: two copies. But the question, of course is why, right,
44:02
Speaker 1: why should particles have any copies? You know, there's like
44:05
Speaker 1: matter and antimatters, the particles have like a single reflection.
44:08
Speaker 1: Why do these particles have these weird, heavier copies and
44:11
Speaker 1: why two of them? That's totally unexplained. It's just sort
44:15
Speaker 1: of like what we see, and to me, it's like
44:17
Speaker 1: a hint. Is suggests that there's something happening underneath out
44:21
Speaker 1: of which this emerges, but we just don't understand anything
44:23
Speaker 1: about what that is. We do we know for sure
44:26
Speaker 1: there are only two or three generations of particles, or
44:29
Speaker 1: is that just what we've found, or it can find
44:32
Speaker 1: with our colliders. Is it possible that there's an infinite
44:34
Speaker 1: number of generations we just can never get to them
44:37
Speaker 1: because they require too much energy. It's a really cool question.
44:40
Speaker 1: We're pretty sure that there are only three kinds of
44:43
Speaker 1: each of these particles, and the reason actually is the
44:46
Speaker 1: Higgs boson, because the Higgs boson interacts with all of
44:49
Speaker 1: these particles. So when we make the Higgs boson at
44:51
Speaker 1: the large Hagon collider, we sort of make it out
44:54
Speaker 1: of these particles. We throw corks and gluons together and
44:58
Speaker 1: make a sort of a frothing mass of energy g
45:00
Speaker 1: and the Higgs boson pops out of that frothing mass.
45:03
Speaker 1: And it does so because it interacts with all of
45:05
Speaker 1: those particles. And so the rate at which interacts with
45:08
Speaker 1: those particles determines how often it's made. And if there
45:11
Speaker 1: were more of these kinds of particles, if there was
45:13
Speaker 1: like a super top cork, or like a heavier bottom
45:16
Speaker 1: cork than the theory predicts, the Higgs boson would be
45:18
Speaker 1: made much more often. So by measuring how often the
45:21
Speaker 1: Higgs boson is made in our collisions, we can actually
45:25
Speaker 1: measure how many generations of particles there are. Because the
45:28
Speaker 1: number of generations determines how often we make the Higgs boson.
45:32
Speaker 1: So we're really pretty sure there are three. But we
45:35
Speaker 1: don't know is why there are three. What could there
45:37
Speaker 1: be maybe uh, super higgs boson or heavier higgs boson,
45:42
Speaker 1: or another generation of Higgs bosons that we don't know about.
45:46
Speaker 1: There definitely could be We did a whole podcast about
45:48
Speaker 1: other Higgs bosons and it might be there. And there
45:51
Speaker 1: might also be other kinds of corks. They just would
45:54
Speaker 1: be different, like they don't talk to our Higgs boson
45:56
Speaker 1: or they're different in some way. So precisely, the statement
45:59
Speaker 1: we can make is these kinds of corks, the quirks
46:02
Speaker 1: we have found so far, we're pretty sure there are
46:04
Speaker 1: only three of them. But there could be other kinds
46:07
Speaker 1: of weird corks that don't talk to the Higgs the
46:09
Speaker 1: same way and do other stuff that are out there.
46:11
Speaker 1: And there's no limit on how many other weird heavy
46:14
Speaker 1: particles could exist that we just haven't found yet. MM.
46:17
Speaker 1: But I think what you're saying is if you look
46:18
Speaker 1: at the math, if you look at the math of
46:20
Speaker 1: the Standard model, it doesn't prevent you from having more
46:23
Speaker 1: generations or have your cousins of the electron. It's just
46:26
Speaker 1: that experimentally, you haven't seen any or seen any evidence
46:30
Speaker 1: that more could be there. Yeah, directly, we haven't found
46:33
Speaker 1: a name. We've looked, and indirectly we have some constraints
46:36
Speaker 1: because we think if they exist, they would influence how
46:38
Speaker 1: often the Higgs boson is made, the large Hagon collier.
46:41
Speaker 1: But mathematically there's no limit, that's right. Mathematically there's no limit. Yeah,
46:45
Speaker 1: there's no reason the Standard model couldn't have four or
46:48
Speaker 1: seven generations or ninety thousand generations and particles. Mathematically there's
46:52
Speaker 1: no reason why not. But it's an interesting clue, and
46:55
Speaker 1: people wonder, like, what does it mean that there are
46:57
Speaker 1: three is the universe? Like three? Ish? Is this just
47:00
Speaker 1: what it is? Or is there a reason for it? All? Right?
47:03
Speaker 1: What else is unexplained? Another really fund mystery is neutrinos. Right,
47:07
Speaker 1: Neutrinos are part of this basic list, and we know
47:10
Speaker 1: they exist and they're out there and that there are
47:12
Speaker 1: three kinds of them, but we really don't understand their masses.
47:16
Speaker 1: We know that they do have mass, and those masses
47:19
Speaker 1: are very very small, but our theory, the Standard model,
47:22
Speaker 1: actually doesn't allow them to have any mass. The theory
47:24
Speaker 1: requires that they have zero mass, and we go out
47:27
Speaker 1: there and we measure them and we see that they
47:28
Speaker 1: do have mass. And so this is actually where people
47:31
Speaker 1: disagree about what is the standard model. The sort of official,
47:34
Speaker 1: official standard model has neutrinos with no mass, and now
47:38
Speaker 1: people have like a new version of the standard model
47:40
Speaker 1: where they've incorporated neutrino mass, and some people say that's
47:43
Speaker 1: the standard model. Wait, what do you mean the standard
47:45
Speaker 1: model doesn't allow the neutrino to have mass. What does
47:48
Speaker 1: that mean? Well, this sort of old school standard model
47:51
Speaker 1: has a bunch of rules for what these particles can do.
47:53
Speaker 1: Like you have to keep track of the number of electrons.
47:56
Speaker 1: You can't just create or destroy electrons. You have to
47:58
Speaker 1: keep track of them and conserve number of electrons in
48:01
Speaker 1: the universe. It's like a hard and fast rule in
48:03
Speaker 1: the old school standard model. But if the electron neutrino
48:06
Speaker 1: has a little bit of mass, then it can do
48:08
Speaker 1: something tricky to sort of break this accounting. We had
48:11
Speaker 1: a whole podcast episode recently about sterile neutrinos and and
48:14
Speaker 1: all this kind of stuff, and so it breaks that
48:16
Speaker 1: rule in the old school standard model. So if neutrinos
48:18
Speaker 1: have mass, and that hard and fast rule, and the
48:20
Speaker 1: old school standard model doesn't really hold up anymore as
48:23
Speaker 1: a hard and fast rule. It's like approximate now. So
48:26
Speaker 1: we have that sort of an updated version of the
48:28
Speaker 1: standard model where you give neutrinos mass and it breaks
48:31
Speaker 1: these rules a little bit. Some people consider that the
48:33
Speaker 1: standard model, and some people consider that beyond the standard model.
48:38
Speaker 1: What happens if you do allow mass in the standard
48:40
Speaker 1: model for neutrinos? Are you're saying, other contradictions pop up? Yeah,
48:44
Speaker 1: we don't really understand how that works yet. There's a
48:45
Speaker 1: bunch of experiments to try to measure those neutrino masses
48:48
Speaker 1: and they don't agree with each other. There's a question
48:51
Speaker 1: about are there actually just three neutrinos or is there
48:53
Speaker 1: like a sly fourth neutrino out there, the sterile neutrino
48:56
Speaker 1: that's been messing up a few experiments that are out there.
48:59
Speaker 1: We don't understand if neutrinos get mass the same way
49:02
Speaker 1: the other particles do through the Higgs boson, or if
49:05
Speaker 1: they're a really weird particle, like maybe they are their
49:08
Speaker 1: own anti particle particle called a maorona. Particle which would
49:12
Speaker 1: get mass in a completely different way, not from the
49:14
Speaker 1: Higgs boson. So neutrinos are so of the next frontier,
49:17
Speaker 1: like a part of the standard model that we've only
49:19
Speaker 1: really just begun to explore and really haven't nailed down
49:22
Speaker 1: very well. Interesting. Well, we don't have a lot of
49:24
Speaker 1: time left, but there are still some interesting things missing
49:27
Speaker 1: from the standard model. Maybe you want to step of
49:30
Speaker 1: studies pretty quick. There's so many things we couldn't even
49:32
Speaker 1: cover them all. One of my favorites is a question
49:35
Speaker 1: of whether there are particles out there that have just
49:38
Speaker 1: a north or just a south magnetic charge, Like there
49:41
Speaker 1: are particles out there that have a positive or negative
49:44
Speaker 1: electric charge, but so far, every particle we've seen in
49:47
Speaker 1: the universe has a balanced magnetic charge, like you see
49:50
Speaker 1: particles with north poles and south poles. You never see
49:53
Speaker 1: particles with just a north pole or just a south pole.
49:56
Speaker 1: That would be called a magnetic monopole. And actually the
50:00
Speaker 1: theory prefers that they do exist, Like if they do
50:03
Speaker 1: exist and the the theory is more symmetric, it's more balanced
50:06
Speaker 1: than if they don't exist. So it's kind of a
50:09
Speaker 1: mystery why we don't see them in the universe, and
50:12
Speaker 1: a lot of physicists believes that they must exist somewhere
50:15
Speaker 1: out there in the universe, but we've never found one.
50:18
Speaker 1: But probably the deepest question that's open and remaining for
50:21
Speaker 1: the standard model is what's next. We look at all
50:24
Speaker 1: these particles and we wonder, like, is this the base
50:27
Speaker 1: description of reality? It can't possibly be there all so
50:30
Speaker 1: many weird patterns we don't understand. And you know, a
50:32
Speaker 1: hundred years ago we looked at the periodic table, we
50:34
Speaker 1: saw these weird patterns we didn't understand. Turns out all
50:37
Speaker 1: those patterns were clues that said, oh, there's something deeper
50:40
Speaker 1: going on. All these patterns are just complexity that arise
50:43
Speaker 1: from how the little bits that things are made out
50:45
Speaker 1: of fit together. So now we're looking at the periodic table,
50:48
Speaker 1: the fundamental particles, and we're seeing all these patterns that
50:51
Speaker 1: we don't understand, trying to explain them and wondering if
50:54
Speaker 1: they're made out of some smaller bits that we haven't
50:56
Speaker 1: yet seen, and maybe those bits are made of smaller bits,
50:59
Speaker 1: and those bit are made of smaller bits, and maybe
51:01
Speaker 1: this like a hundred levels between us and the base
51:04
Speaker 1: layer of reality, or maybe just one or two, or
51:07
Speaker 1: maybe there's no bottom. Yeah, I guess it's kind of
51:10
Speaker 1: tricky because at some level you have the standard model
51:12
Speaker 1: and you're seeing these patterns and maybe hinted something deeper.
51:15
Speaker 1: But at the same time you also know that the
51:17
Speaker 1: standard model is not correct, right, Like you know they
51:20
Speaker 1: has hu mongous gaps in it and lots of things missing.
51:23
Speaker 1: Kind of makes you wonder how much you should read
51:25
Speaker 1: into these patterns, or whether even exploring those patterns is
51:29
Speaker 1: going to be useful. Yeah, we don't know what the
51:30
Speaker 1: best way forward is. When you read the history of physics,
51:33
Speaker 1: it's written to sound kind of linear, like we did this,
51:35
Speaker 1: and then we figure that out, and then we figure
51:36
Speaker 1: this other thing out. But remember that at the same time,
51:38
Speaker 1: there were lots of other branches. People were exploring other
51:41
Speaker 1: crazy ideas which made sense to them at the time
51:44
Speaker 1: when they were at the forefront of human knowledge. But
51:46
Speaker 1: we mostly erased those other zigzags and those other branches
51:50
Speaker 1: from our history of physics to give you a description
51:52
Speaker 1: of sort of the theory we ended up at. But
51:55
Speaker 1: now we're here at the forefront of human knowledge right now,
51:58
Speaker 1: we just don't know what is the right way forward.
52:00
Speaker 1: Should it be quantum gravity, Should it be anti matters,
52:02
Speaker 1: Should it be magnetic monopoles? Should it be cracking open
52:05
Speaker 1: the electron to see what's inside. We don't know what's
52:08
Speaker 1: going to yield some inside, so we're all just sort
52:11
Speaker 1: of like being curious and exploring and hoping to figure
52:13
Speaker 1: something out. So the basic answer is that we've given
52:16
Speaker 1: you all this money and still wide open question. It's
52:20
Speaker 1: still a wide open question, which makes for a wonderful,
52:23
Speaker 1: mysterious universe that we get to keep talking about on
52:26
Speaker 1: the podcast. It sounds like maybe the answer to getting
52:28
Speaker 1: are great as a species in the giant physics exam
52:32
Speaker 1: of the universe is to ask for an extension. Daniel,
52:36
Speaker 1: what's your policy and given students extensions. I'm pretty lenient. Actually, yeah,
52:40
Speaker 1: I'm pretty lenient. What if they come to you say, hey,
52:41
Speaker 1: instead of doing physics, I've been spending all my money
52:44
Speaker 1: making Marvel movies and creating Netflix. Can I get an extension? Yeah? Sure?
52:51
Speaker 1: Can I get some free tickets? I see you're open
52:53
Speaker 1: to being bribed as a greater No. I think people
52:59
Speaker 1: should go out there and explore their passions and discover
53:01
Speaker 1: who they are, and everybody can contribute in some way
53:04
Speaker 1: to this incredible journey we call life and the exploration
53:07
Speaker 1: of the universe. It sounds like a standard answer, Danny, Well,
53:10
Speaker 1: stay tuned as we keep exploring the universe and discovering
53:13
Speaker 1: more about what we know and when we don't know
53:16
Speaker 1: about this amazing cosmos. We hope you enjoyed that. Thanks
53:20
Speaker 1: for joining us, See you next time. Thanks for listening,
53:30
Speaker 1: and remember that Daniel and Jorge Explain the Universe is
53:33
Speaker 1: a production of I Heart Radio. For more podcast from
53:37
Speaker 1: my Heart Radio, visit the i heart Radio app, Apple Podcasts,
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Speaker 1: or wherever you listen to your favorite shows.