Latest / Daniel and Kelly’s Extraordinary Universe / What's the most promising theory of EVERYTHING?

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What's the most promising theory of EVERYTHING? · Daniel and Kelly’s Extraordinary Universe

0:08
Speaker 1: Hey, Daniel, what's the one thing you most want to
0:11
Speaker 1: understand about the universe? I think I might say everything
0:17
Speaker 1: does everything count? Is one thing? Well, it does if
0:20
Speaker 1: we understand all of it together and how it's all
0:23
Speaker 1: like connected, you mean, like how we're all one with
0:25
Speaker 1: the universe? Man, exactly past the banana peels. Man, that's
0:30
Speaker 1: the goal. So when you go through an ice cream
0:32
Speaker 1: store and they say, pick one scoop of ice cream,
0:35
Speaker 1: do you try to order everything? Also? Yeah, I do.
0:38
Speaker 1: I try to convince them of my unifying theory of
0:40
Speaker 1: ice cream, you know that unifying your veins to right,
0:43
Speaker 1: and do my best to bring it all together. Well,
0:45
Speaker 1: at least it's insightful and delicious. Hi am Jorge. I'm
1:04
Speaker 1: made cartoonists and the creator of PhD Comics. Hi I'm Daniel.
1:07
Speaker 1: I'm a particle physicist and I eat a lot less
1:10
Speaker 1: ice cream than I thought I would when I was
1:12
Speaker 1: a kid. What do you mean you had a projection
1:14
Speaker 1: as a kid and you're not meeting the expectations. No,
1:17
Speaker 1: when you're a kid and you think, Wow, when I
1:18
Speaker 1: grow up and I get to decide what I eat,
1:20
Speaker 1: I'm just gonna eat ice cream all day. But turns
1:23
Speaker 1: out that's not really what I want. Really, what happened?
1:26
Speaker 1: You change your mind? You haven't found your perfect ice
1:29
Speaker 1: cream flavor yet. Maybe I just ate too much ice
1:31
Speaker 1: cream in college and I'm just done. Oh so you did,
1:35
Speaker 1: I accomplish your goal. It's just that you know, you
1:37
Speaker 1: found out that once you achieve your goals, then you
1:40
Speaker 1: know life goes on. Yeah, maybe I blew through that
1:43
Speaker 1: one a little too quick, and I gotta move on
1:45
Speaker 1: to something else. I maybe it's the opposite. Life stops
1:47
Speaker 1: going on, and you eat too much ice cream and
1:50
Speaker 1: you realize that maybe that's it. Maybe life should be
1:53
Speaker 1: measured in scoops of ice cream. Maybe everybody lives the
1:55
Speaker 1: same number of scoops of ice cream and you blew
1:58
Speaker 1: it all in your twenties. But welcome to our podcast.
2:00
Speaker 1: Daniel and Jorge Explain the Universe, a production of I
2:03
Speaker 1: Heart Radio in which we try to take a big
2:06
Speaker 1: scoop out of the universe. We serve you up a
2:08
Speaker 1: delicious ball of sweet sweet understanding of the mysteries of
2:13
Speaker 1: the universe. We talk about everything that's out there in space,
2:17
Speaker 1: the crazy stuff colliding and producing gold, the weird stuff
2:20
Speaker 1: in tiny little particles. We think about where it all
2:23
Speaker 1: came from, where it's all going, and what it's all
2:25
Speaker 1: gonna do, and we try to make sure all of
2:27
Speaker 1: it makes sense to you with a cherry on top
2:31
Speaker 1: and some sprint. Because even ice cream is made out
2:34
Speaker 1: of physics, right, The ice cream is made out of particles,
2:36
Speaker 1: which are made out of subparticles, which are made out
2:39
Speaker 1: of sub subparticles. Try the same particles that everything else
2:41
Speaker 1: in the universe is made out of. Stars, planets, moons, asteroids.
2:46
Speaker 1: It's all sort of one big, continuous, giant, delicious, mostly
2:51
Speaker 1: frozen universe with sprinkles on top. Absolutely, it's amazing, Yes,
2:56
Speaker 1: But this picture that we can take the universe and
2:59
Speaker 1: like reduce it to tiny particles so far seems to work.
3:03
Speaker 1: All the crazy stuff that's out there, it seems so different,
3:06
Speaker 1: but we can explain most of it by boiling it
3:09
Speaker 1: down to a few little bits and how those bits
3:12
Speaker 1: fit together. And you know why, I don't know why
3:14
Speaker 1: we live in the universe like that. It could have
3:16
Speaker 1: been that we lived in a different kind of universe,
3:18
Speaker 1: one where every kind of thing has its own particle.
3:21
Speaker 1: And you don't really get any simplification when you try
3:24
Speaker 1: to take it down to the lower level. But fortunately
3:26
Speaker 1: we do live in a sort of lego universe where
3:29
Speaker 1: there are a few basic building blocks and everything comes
3:31
Speaker 1: out of the arrangements of those. Yeah, it is pretty
3:34
Speaker 1: odd to think about, right, Like, even frogs are made
3:37
Speaker 1: of the same thing as you know, quasars and giant
3:41
Speaker 1: asteroids floating in space. It's all sort of made out
3:44
Speaker 1: of the same little bits and pieces. And it's not
3:47
Speaker 1: just like the same types of bits. It's actually the
3:49
Speaker 1: same bits and a basically the same proportions. You have
3:52
Speaker 1: the same ratio of protons, neutrons, and electrons and basically
3:56
Speaker 1: every element and every element it makes everything. And that
4:00
Speaker 1: means that basically everything you've ever eaten is just a
4:02
Speaker 1: different arrangements of the same number of protons, neutrons, and electrons. Yeah,
4:08
Speaker 1: and it seems like there aren't that many of those particles,
4:11
Speaker 1: right Like, as far as we know, the standard theory
4:13
Speaker 1: of physics says that right now, we think there are
4:15
Speaker 1: about only what is it, twelve particles in the entire universe. Well,
4:20
Speaker 1: it sort of depends on how you ask, right, Like,
4:22
Speaker 1: most of the stuff we see out there in the
4:24
Speaker 1: universe is made out of only three of them of
4:26
Speaker 1: quirks down corks, which give you protons and neutrons, and
4:30
Speaker 1: then electrons. You only need those three to make most
4:32
Speaker 1: of the stuff. But then we have found other particles,
4:35
Speaker 1: and you're right, we're up to twelve now matter particles.
4:38
Speaker 1: But we don't know if those twelve particles are actually fundamental,
4:42
Speaker 1: if they're made of something smaller, or if there are
4:44
Speaker 1: more particles out there. There could be like twelve million particles.
4:48
Speaker 1: We just haven't found most of them yet. I guess
4:50
Speaker 1: it's kind of like how we, you know, discovered the
4:52
Speaker 1: periodic table of the elements at some point, and we
4:55
Speaker 1: thought we had everything figured out, and then it turned
4:58
Speaker 1: out that each of those elements is actually like a
5:01
Speaker 1: copy or a repeat of the same sort of smaller
5:04
Speaker 1: particles electrons, protons, and neutrons, And even though it turned
5:08
Speaker 1: out to be made out of other particles. And another
5:10
Speaker 1: flabbergasting and amazing fact of the philosophy of science is
5:13
Speaker 1: that we seem to be able to understand the universe
5:16
Speaker 1: differently but effectively. All of these different levels like chemistry
5:20
Speaker 1: kind of makes sense, right. You don't need to know
5:22
Speaker 1: all the details of the particles for that to work,
5:24
Speaker 1: and then you drill down into the atomic physics and
5:26
Speaker 1: that kind of makes sense, and nuclear physics makes sense,
5:29
Speaker 1: and then you get down to like the tiny, tiny
5:31
Speaker 1: particle physics, and there's all these sort of layers at
5:34
Speaker 1: which you can think about the universe made of pieces,
5:37
Speaker 1: and the rules of those pieces are understandable. But we
5:40
Speaker 1: can also drill down and find even smaller pieces. So
5:43
Speaker 1: it's incredible to me that there are these layers of understanding.
5:46
Speaker 1: You don't have to go all the way to the
5:48
Speaker 1: tiniest bits in order to make sense of the universe
5:51
Speaker 1: around you. And just like how you use the word flabbergasting,
5:54
Speaker 1: I am flabbergasted. I am grateful and amazed that the
5:59
Speaker 1: univers is sensible. You know, sometimes listeners right to me
6:03
Speaker 1: and they ask, like, do you think it's possible for
6:05
Speaker 1: us to understand the universe? That one day far in
6:08
Speaker 1: the future humans will understand everything? And you know, I
6:12
Speaker 1: don't know the answer to that. Obviously we can't know,
6:15
Speaker 1: But you know, I don't think dogs will understand the universe.
6:18
Speaker 1: We're a little smarter than dogs, but I don't think
6:20
Speaker 1: we're maximally smart. So there's certainly a chance that we won't,
6:24
Speaker 1: so I'm just kind of grateful and flabbergasted that we
6:27
Speaker 1: figured anything out right. I think maybe dogs understand the
6:30
Speaker 1: universe to the extent that it serves them, you know,
6:34
Speaker 1: like most dogs probably feel like they have a pretty
6:36
Speaker 1: good sense of the universe around them and they are uncomfortable.
6:39
Speaker 1: Maybe that's it's our future, you know. We'll just understand
6:42
Speaker 1: it as far as getting our treats and our rubs
6:44
Speaker 1: and the tummy go, and then maybe we'll stop. Well.
6:47
Speaker 1: I think dogs would definitely be better off if they
6:49
Speaker 1: were smarter. Like my dog thinks that every time the
6:52
Speaker 1: refrigerator opens, it's getting a treat, but that's definitely not true.
6:56
Speaker 1: And if it understood, like you know, how to open
6:58
Speaker 1: the fridge on its own, or what time of day
7:01
Speaker 1: typically gets a treat, or what it should do to
7:03
Speaker 1: encourage us to give it a treat, I think we'd
7:05
Speaker 1: get more treats and waste less time. Yeah, but then
7:07
Speaker 1: you just eat ice cream all day, Daniel. Maybe dogs
7:10
Speaker 1: are smarter than you think. I'm pretty sure a dog
7:13
Speaker 1: would eat ice cream all day. Have the chance, let's
7:16
Speaker 1: do that experiment. Let's put some ice cream in front
7:18
Speaker 1: of a dog and see what happens. Maybe the key
7:20
Speaker 1: to happiness, Daniel, is not getting what you want, to
7:22
Speaker 1: be optimistic about getting what you want. Maybe dogs are
7:26
Speaker 1: one with the universe more than we are. Well, maybe
7:28
Speaker 1: this is turning into a dog psychology podcast. Welcome to
7:31
Speaker 1: the dog whispering philosophizing Daniel and Jorge explain your pets
7:36
Speaker 1: to you. Oh my god, that is a winning podcast idea.
7:40
Speaker 1: Let's pive it here, Daniel, your cat is really just
7:42
Speaker 1: not that into you. Yeah, and now tell me about
7:46
Speaker 1: your rats. Do they get flabbergasted as well? Our rats
7:49
Speaker 1: have unfortunately passed away because rats only live a couple
7:51
Speaker 1: of years. They're wonderful pets. They're smart, they're intelligent, they're responsive,
7:56
Speaker 1: they're actually affectionate, but they are sort of short lived.
7:58
Speaker 1: It was a bit sad. That's why we now have
8:00
Speaker 1: a dog. I'm sorry. I guess they went back to
8:03
Speaker 1: being particles. They live on. Their particles live on through
8:06
Speaker 1: the universe. It seems like it's all connected. Everything's made
8:09
Speaker 1: out of the same basic particles, which I think makes
8:12
Speaker 1: physicists wonder if you can go further and break things
8:15
Speaker 1: out even more and maybe get down to one particle
8:18
Speaker 1: or one type of particle that ties the entire universe
8:22
Speaker 1: together into one theory. We would love to do that.
8:26
Speaker 1: To explain everything in terms of one equation, we could
8:28
Speaker 1: just write on a T shirt, hopefully not a big
8:30
Speaker 1: T shirt, on a onesie or maybe like one with
8:34
Speaker 1: extra long coattails. That would be a new fashion statement,
8:38
Speaker 1: or in super duper tiny font that you need reading
8:40
Speaker 1: glasses to read. Now, we want a simple theory. We
8:43
Speaker 1: want to reveal the fundamental nature of the universe. A
8:46
Speaker 1: goal of physics is not just to optimize our ice
8:48
Speaker 1: cream intake, but to sort of understand, to have that
8:51
Speaker 1: moment where we're like we get it, We're like, oh,
8:54
Speaker 1: that's how the universe works. And to do that, we
8:57
Speaker 1: want one simple idea that tells us what rules are. Yeah,
9:00
Speaker 1: it's a big goal in physics. It's the ultimate dream,
9:03
Speaker 1: perhaps of a physicist to discover it. And so today
9:06
Speaker 1: on the podcast, we'll be asking the question, what's the
9:14
Speaker 1: most promising theory of everything? Everything, everything, everything, like everything right,
9:21
Speaker 1: like all of it. Yeah. I guess you could also
9:23
Speaker 1: call it the most promising theory of the universe. Yeah,
9:26
Speaker 1: except that these days we've gone beyond the universe. We
9:29
Speaker 1: have the multiverse, and so you know, maybe you should
9:32
Speaker 1: call it the every verse or the olive verse or something.
9:35
Speaker 1: Everything's most promising theory of Everything's you can't have Everything's.
9:40
Speaker 1: That could be the sequel through the Theory of everything
9:42
Speaker 1: in the movie The Theory of Everything's the theory of
9:46
Speaker 1: the theory of everything. Yeah, so it's a goal in
9:49
Speaker 1: physics to come up with one, I guess, one equation, Daniel,
9:51
Speaker 1: what do you think this theory will look like? One equation? One? Hey? Well, one,
9:57
Speaker 1: you know, fortune cookie, piece of paper will What will
10:00
Speaker 1: this theory look like? What will this theory look like? Wow?
10:03
Speaker 1: I wish I knew. You know, Currently we use math
10:06
Speaker 1: as the way we express our ideas. Matter and forces
10:10
Speaker 1: are both described by fields, which are expressed as quantum
10:13
Speaker 1: field theories, and so one hope is that we could
10:16
Speaker 1: generalize quantum field theory and use it to describe things
10:20
Speaker 1: at the smallest level. But you know, we've explored a
10:23
Speaker 1: tiny little fraction of the universe. As you say, the
10:26
Speaker 1: universe is mostly cold and things are moving slowly, and
10:29
Speaker 1: it could be that what we've learned is not representative,
10:33
Speaker 1: and it's always dangerous to extrapolate from like a tiny
10:36
Speaker 1: little corner or the universe to the rest of it.
10:38
Speaker 1: You wouldn't say you understand elephants if you've only ever
10:40
Speaker 1: looked at one elephant's tale, for example. And so I'd
10:44
Speaker 1: love if quantum field theory was the path forward. But
10:47
Speaker 1: I suspect we need some sort of completely new kind
10:50
Speaker 1: of mathematics in order to make progress towards this final theory.
10:55
Speaker 1: And you have to discover new math before you can
10:57
Speaker 1: discover a new physics. Absolutely, we're constantly inventing or discovering
11:01
Speaker 1: new math to make progress. It's this fantastic sort of
11:04
Speaker 1: duet between math and physics. Mathematicians invent some new tool,
11:08
Speaker 1: they're like, hey, this is useless but fun, and the
11:11
Speaker 1: physicists are like, wait, I can use that for something.
11:13
Speaker 1: Bring that over here. I'm gonna build that into my theory.
11:16
Speaker 1: And I'm never actually sure whether mathematicians are like delighted
11:18
Speaker 1: to have their tools find use or a little disappointed
11:21
Speaker 1: that they've been like sullied by brought into the physical world.
11:24
Speaker 1: Do you think they see you as a duet partner
11:26
Speaker 1: or as like a backup singer. Oh, I definitely think
11:28
Speaker 1: that mathematicians think of physicists as sort of like unnecessary
11:32
Speaker 1: frosting on the cake, you know. I think mathematicians see
11:36
Speaker 1: themselves as more primary and fundamental than physicists, the way
11:39
Speaker 1: I think a lot of physicists think about chemistry and biology,
11:42
Speaker 1: you know, sort of these like layers of the onion.
11:44
Speaker 1: I heard one mathematician described his department as the halls
11:47
Speaker 1: of truth without irony, the halls of snobbery, which trickles down,
11:54
Speaker 1: is what you're saying, is a trickle down effect for
11:56
Speaker 1: snobbery in the sciences. There's a whole hierarchy of snobbery. Absolutely. Meanwhile,
12:00
Speaker 1: everyone uses their phones and computers which are made for
12:04
Speaker 1: by engineers to do their science exactly, and it's not
12:07
Speaker 1: just limited to science. Snobberries everywhere. But anyways, this is
12:11
Speaker 1: a big question, a lofty goal, and we were wondering,
12:14
Speaker 1: as usual, if people out there on the Internet had
12:16
Speaker 1: ideas about everything, which sounds like a redundant question. As usual,
12:21
Speaker 1: Daniel went out there and asked people if they knew
12:24
Speaker 1: what the most promising theory of everything is. And so
12:27
Speaker 1: thank you to everybody who have volunteered, and especially to
12:30
Speaker 1: our recurring superstar Lucien who has volunteered. I think consecutively
12:33
Speaker 1: for every single one of the last forty episodes. If
12:37
Speaker 1: you'd like to participate, please don't be shy. Right to me.
12:39
Speaker 1: Two questions at Daniel and Jorge dot com. Think about
12:43
Speaker 1: it for a second. What do you think is the
12:44
Speaker 1: most promising theory of everything? Here's what Lucian and a
12:49
Speaker 1: lot of other people had to say. Um, I don't
12:52
Speaker 1: know much about theories of everything. You only want to
12:59
Speaker 1: know of it about is string theories as the one
13:04
Speaker 1: I think is maybe string theory, which I've also heard
13:12
Speaker 1: referred to as brain theory, has that it evolved a
13:15
Speaker 1: little bit instead of just strings. Now they're saying maybe
13:17
Speaker 1: it's membranes. I didn't know there was more than one
13:21
Speaker 1: theory of everything. That's pretty cool. Something to do with
13:25
Speaker 1: the theory that unifies general relativity and quantum theory. Maybe
13:31
Speaker 1: it makes me think of social media. If you go there,
13:36
Speaker 1: you help. You'll have people having theories about everything. But
13:43
Speaker 1: the most promising one it's the superstring theory a guess
13:48
Speaker 1: um um um ones that Brian Green and and others
13:57
Speaker 1: are walking working on it. I'd say the most promising
14:02
Speaker 1: theory of everything is the Big Bang theory. Uh. It
14:06
Speaker 1: encompasses all of the sciences anties them together neatly into
14:11
Speaker 1: a theory for cosmology and you know, especially for chemistry, physics,
14:18
Speaker 1: all of it. It just seems to go together. Well.
14:21
Speaker 1: I like string theory, but I'd say the Big Bang
14:25
Speaker 1: theory is about her. Dr Michio Kaku speaks of an elusive,
14:30
Speaker 1: elegant equation, perhaps an inch or so long, that operates
14:33
Speaker 1: in both the quantum and relativistic realms. I would have
14:37
Speaker 1: to side with Professor Cocku and nominate string theory as
14:41
Speaker 1: the most promising, but I think that squeezing all that
14:44
Speaker 1: math down to an inch will be a bit of
14:47
Speaker 1: a stretch. I will vote for string total Well. I
14:53
Speaker 1: happen to think Luke quantum gravity is on the right track,
14:56
Speaker 1: but that's not actually a theory of everything. String theory
15:00
Speaker 1: seems to be losing favor, as I think is also
15:03
Speaker 1: M theory, the many worlds explanation of things. It's always
15:07
Speaker 1: right because there's always a place where it's right. I
15:09
Speaker 1: don't really know the answer. I think the most promising
15:13
Speaker 1: theory of everything is the M theory that can only
15:17
Speaker 1: be done by that one guy whose name I can't remember,
15:20
Speaker 1: and nobody else seems to understand it all right, I
15:23
Speaker 1: think I just realized something, Daniel, What's the acronym for
15:26
Speaker 1: a theory of everything is t o e toe? So
15:30
Speaker 1: really you're looking for the big toe of the universe. Yeah.
15:33
Speaker 1: That's sort of tough to reconcile with the snobbery of
15:35
Speaker 1: particle physics, isn't it. What do you mean? Are you
15:37
Speaker 1: saying toes aren't ignoble somehow or not worthy the highest regard?
15:43
Speaker 1: Definitely exactly. Toes make me think of, you know, toe cheese.
15:46
Speaker 1: It's kind of smelly. You can stub your toe, you know.
15:48
Speaker 1: Toes not like poetry written about people's toes very often?
15:52
Speaker 1: Haven't there been love songs devoted to toes? Are some
15:56
Speaker 1: people into toes? I'm into theories of everything, so maybe
15:59
Speaker 1: put me in that kind gregory of being into your
16:02
Speaker 1: toe theory finishist, But our listeners have definitely thought about
16:05
Speaker 1: the theory of everything. There were some good answers here,
16:07
Speaker 1: A lot of people engine string theory. I feel like
16:09
Speaker 1: people are maybe familiar with that idea that maybe it
16:12
Speaker 1: could be a theory of everything. Yeah, and thank you
16:15
Speaker 1: to all those listeners. And I want to make a
16:16
Speaker 1: shout out to one of our youngest listeners, two and
16:19
Speaker 1: a half year old Hannah from Australia. Her dad wrote
16:23
Speaker 1: to me and said that she was home from childcare
16:25
Speaker 1: was sick, and she asked him can we listen to
16:27
Speaker 1: Daniel and Jorge. So thanks Hannah for listening to our podcast.
16:31
Speaker 1: And you said, obviously the answer is no, right. I'm
16:33
Speaker 1: not her dad. We're not qualified to take care of children, Daniel,
16:37
Speaker 1: especially not other people's children. I think Hannah should get
16:40
Speaker 1: some more ice cream. What do you think, Joey. I
16:41
Speaker 1: think she should maybe be listening to some math podcasts instead.
16:45
Speaker 1: But I said, a lot of ideas out there about
16:48
Speaker 1: the theory of everything, So let's break it down for people,
16:50
Speaker 1: and so real quick, Daniel, what would you say is
16:53
Speaker 1: theory of everything? How would you define it? Well? Everything
16:56
Speaker 1: for physicists means like all the experiments. We want to
17:00
Speaker 1: explain basically anything that you can do. We want to
17:03
Speaker 1: be able to predict what happens. We don't want any surprises.
17:07
Speaker 1: We want to be able to say, if you smash
17:09
Speaker 1: these two particles together, here's what's gonna happen. If you
17:12
Speaker 1: drop a feather on the moon, here's what's going to
17:14
Speaker 1: happen if you bring all this matter together. Here's how
17:17
Speaker 1: a black hole forms. We want to be able to
17:19
Speaker 1: predict what happens. We want to know what the rules are,
17:22
Speaker 1: and so at the most fundamental level, that means explaining
17:25
Speaker 1: all the kinds of bits of stuff there are out there,
17:27
Speaker 1: all the matter, and then all the rules about how
17:30
Speaker 1: those bits talk to each other, so like all the forces.
17:33
Speaker 1: So put simply, we want a single description, a single idea,
17:37
Speaker 1: a single mathematical equation that explains all the matter and
17:41
Speaker 1: all the forces in the universe, like one theory, one framework,
17:46
Speaker 1: or one equation that can tell you what's gonna happen,
17:49
Speaker 1: or maybe not what's gonna happen, but what's likely to happen. Right, Yeah, exactly.
17:52
Speaker 1: Our universe is quantum mechanical, which means we can't say
17:55
Speaker 1: exactly what will happen, but it's still deterministic because we
17:59
Speaker 1: can say what's likely to happen. We can say, if
18:01
Speaker 1: you shoot an electron at a proton at this angle,
18:04
Speaker 1: here's exactly the distribution of possible outcomes, And so the
18:08
Speaker 1: wave function is still deterministic, even if how it collapses
18:12
Speaker 1: is not right or more accurately, Like if I smashed
18:15
Speaker 1: these two particles together a hundred million times, that you
18:19
Speaker 1: should get, you know, approximately ex proportion of this happening
18:23
Speaker 1: or exproportion of that happening. Yeah. If you're a frequentist
18:25
Speaker 1: and that's how you interpret probability, then yeah, exactly, in
18:28
Speaker 1: a hundred millions similar experiments, you would get this distribution
18:31
Speaker 1: of outcome. If you're a basy and then you say, well,
18:33
Speaker 1: there's a probability of various outcomes. Did you just call
18:36
Speaker 1: me a frequentist. Yeah, you just outed yourself as a frequentist.
18:39
Speaker 1: And I know whether I should be offended or flattered.
18:41
Speaker 1: I guess it depends on your posterior. I guess I
18:43
Speaker 1: feel flattered, you know, fifty of the time, offended another
18:47
Speaker 1: fifty percent of the time. No, don't, I'm a frequentist.
18:49
Speaker 1: I think it makes a lot more sense. All right, Well,
18:51
Speaker 1: let's get into some of the details. Who have what
18:54
Speaker 1: a theory of everything would apply to and what are
18:57
Speaker 1: some of the leading candidates right now? But first let's
19:00
Speaker 1: take a quick break. All right, we're talking about the
19:15
Speaker 1: big toe of the universe, the big theory of everything
19:18
Speaker 1: that could maybe one day explain everything that happens and
19:22
Speaker 1: predict exactly how it's all gonna turn out, every little
19:25
Speaker 1: nook and corner of the universe. Right, I know, that's
19:28
Speaker 1: what a theory of everything promises. That's what a theory
19:31
Speaker 1: of everything promises. Yeah, it's to explain everything in terms
19:35
Speaker 1: of one idea. And you know, the history of physics
19:38
Speaker 1: is that we saw a lot of weird stuff and
19:40
Speaker 1: we try to explain sort of each bit, and then
19:43
Speaker 1: we look for patterns and we try to like organize
19:46
Speaker 1: the stuff into groups. We said, well, you know what,
19:48
Speaker 1: maybe lightning and static electricity are actually the same thing.
19:53
Speaker 1: Then we developed like a coherent explanation for electricity, and
19:57
Speaker 1: so the basic step forward there is not to say
20:00
Speaker 1: lightning is static electricity. Obviously they're related, but they're different.
20:04
Speaker 1: You try to fit them together into a common idea,
20:07
Speaker 1: right to say these two things are part of the
20:09
Speaker 1: same larger concept. They both come from the same effect
20:13
Speaker 1: or the same I don't know, equality in the universe
20:16
Speaker 1: or something. Yeah, and you can generalize that a little bit.
20:19
Speaker 1: Like we've made further progress by noticing that there's a
20:22
Speaker 1: deep relationship between electricity and magnetism, right that, like particles
20:27
Speaker 1: that have charges on them, for example, are affected by magnets,
20:30
Speaker 1: and particles that move can make magnets. So this is
20:34
Speaker 1: deep connection between electricity and magnetism, and we unify that
20:38
Speaker 1: into electromagnetism. Again, that doesn't say, oh, electric charges are
20:42
Speaker 1: the same as magnets. It's not saying that they're identical.
20:45
Speaker 1: It's just saying that it makes more sense to fit
20:47
Speaker 1: them together, that there are two sides of the same coin,
20:50
Speaker 1: and mathematically they sort of clicked together like pieces of
20:53
Speaker 1: a puzzle, like they can be predicted by the same equation. Yeah,
20:56
Speaker 1: there's a symmetry in the equations. In fact, if you
20:59
Speaker 1: look at the equation of electromagnetism, you notice that the
21:02
Speaker 1: electric field and the magnetic field have exactly the same
21:05
Speaker 1: and opposite rules. So there's four of those equations, and
21:08
Speaker 1: if you swap the electric field, the magnetic field and
21:11
Speaker 1: all of them, you get the same equations. So that's
21:13
Speaker 1: kind of cool. I guess you know. There's a lot
21:15
Speaker 1: to the universe. There's a lot in the word everything,
21:19
Speaker 1: and so would discover everything like matter, forces, base time.
21:23
Speaker 1: Are you trying to wrap that all up into one equation? Yes, exactly,
21:27
Speaker 1: I want all of it you know, put all those
21:29
Speaker 1: scoops under one big cone. Um. We definitely want to
21:32
Speaker 1: explain matter. Like we were talking about before, we would
21:35
Speaker 1: love to understand what is the most basic element of
21:38
Speaker 1: the universe. First of all, how many basic elements are
21:41
Speaker 1: there in the universe. And by elements, I don't mean,
21:43
Speaker 1: you know, like lead or iron, I mean the most
21:46
Speaker 1: fundamental thing in the universe, the basic ingredient, the smallest
21:51
Speaker 1: piece out of which everything is made. We'd love to
21:53
Speaker 1: understand what that is. You know, we don't think that
21:57
Speaker 1: the current list of particles we have are fundament We
22:00
Speaker 1: don't think that those are the answer, right. They might
22:03
Speaker 1: be reducible too, simpler bits and pieces exactly because when
22:07
Speaker 1: we look at these particles, we notice weird patterns, patterns
22:10
Speaker 1: that don't make any sense, patterns that don't have any explanations.
22:13
Speaker 1: And those patterns are typically historically very valuable clues that
22:18
Speaker 1: lead you to figuring out how to sort of assemble
22:22
Speaker 1: the current list of fundamental particles out of something smaller,
22:25
Speaker 1: to figure out how they might be made out of
22:27
Speaker 1: different combinations of smaller bits. And it would also have
22:30
Speaker 1: to cover the forces, right or or do you count
22:33
Speaker 1: those as particles because forces have particles too, right, Yeah,
22:36
Speaker 1: we would love to explain the forces, and we can
22:38
Speaker 1: explain the forces in terms of fields and then ripples
22:41
Speaker 1: in those fields and being interpreted as particles. Absolutely, So
22:45
Speaker 1: you can think about the universe is made of fields
22:47
Speaker 1: or made of particles either way, So forces you can
22:50
Speaker 1: think about as fields or as particles. But we definitely
22:53
Speaker 1: like to unify these forces and to understand them together.
22:56
Speaker 1: Where we're talking about a minute ago was sort of
22:58
Speaker 1: the unification of electricity and magnism, and we've made a
23:01
Speaker 1: lot of progress there. We've even unified electromagnetism with the
23:05
Speaker 1: weak nuclear force, this force that's responsible for beta decay,
23:09
Speaker 1: radioactive decay, and other sorts of radioactive processes. We understand
23:13
Speaker 1: them now to be like part of one larger mathematical construct,
23:17
Speaker 1: the electro weak force, and we're sure that's correct. We
23:21
Speaker 1: know that that's true, that it reveals something deep about
23:23
Speaker 1: the universe because realizing how those two things clicked together
23:27
Speaker 1: is what allowed us to predict the existence of the
23:29
Speaker 1: Higgs boson, which was a pretty big step in unifying everything.
23:33
Speaker 1: So what this include then also gravity as well? Do
23:36
Speaker 1: you hope to sort of explain gravity in one quantum framework. Yeah, absolutely,
23:41
Speaker 1: we would love to explain all of the forces together.
23:44
Speaker 1: Now we have some forces for which we have a
23:46
Speaker 1: quantum mechanical description, like electromagnetism and the weak force and
23:51
Speaker 1: the strong force. We haven't yet managed to merge all
23:54
Speaker 1: those quantum mechanical forces together. These are the forces that
23:57
Speaker 1: you can describe in terms of a quantum field or
23:59
Speaker 1: part goals passing back and forth. And we have not
24:02
Speaker 1: yet unified the strong force with those other ones, so
24:05
Speaker 1: that's left to be done. We would also like to understand,
24:08
Speaker 1: like is gravity even a force doesn't belong on this list,
24:12
Speaker 1: like you mentioned earlier, We want to unify all the stuff,
24:15
Speaker 1: all the forces, and then space and time, well, our
24:18
Speaker 1: space and time really their own separate thing. Are they
24:20
Speaker 1: just manifestations of some quantum gravitational quantum mechanical force. Are
24:25
Speaker 1: there really something different? We don't understand that at all.
24:28
Speaker 1: So yes, we would like one clear understanding where all
24:31
Speaker 1: the pieces fit together, and all the pieces have to
24:34
Speaker 1: be there, like it's a complete puzzle, not just a
24:37
Speaker 1: few pieces that stick together, Like you don't want to
24:39
Speaker 1: have any bits left over where you're like, what is
24:41
Speaker 1: this for or how does this fit in? I don't know,
24:44
Speaker 1: just you know, keep it there on the side. Now,
24:45
Speaker 1: you want, like the equation is to tell you why
24:48
Speaker 1: that thing is there or why it's not there exactly,
24:51
Speaker 1: and we want the math to lead us there. We
24:53
Speaker 1: want to find like symmetries that say this is the
24:56
Speaker 1: only way these equations work because they have to follow
24:59
Speaker 1: this rule, you know, Like we have symmetries that's say,
25:02
Speaker 1: for example, every inertial frame of reference follows the same
25:06
Speaker 1: law of physics, and that really limits the kinds of
25:09
Speaker 1: laws of physics that you can write. You can only
25:11
Speaker 1: write ones that follow those rules. And we think that
25:13
Speaker 1: that's the symmetry of the universe. So we'd like to
25:16
Speaker 1: sort of find symmetries that tell us how to write
25:19
Speaker 1: the laws of physics. And it would be great if
25:20
Speaker 1: there was only one possibility, if we're like, you know what,
25:23
Speaker 1: this is the only one that sort of works. It
25:25
Speaker 1: hangs together, it has all the pieces we need, doesn't
25:28
Speaker 1: have any extra bits that don't correspond to things we see,
25:32
Speaker 1: and so that would be really beautiful. And then we
25:33
Speaker 1: could look at that and say, Okay, what does this
25:35
Speaker 1: tell us about the universe? What is this reveal about
25:38
Speaker 1: the source code of the universe vanilla? So it's trying
25:43
Speaker 1: to tell us, Daniel, it's the writing on the sweetness
25:45
Speaker 1: wall there. No, I would guess the universe is probably
25:48
Speaker 1: raspberry flavored. You know, there's these huge gas clouds of
25:51
Speaker 1: Ethel's in the center of the galaxy, and you know
25:53
Speaker 1: is responsible for the smell of raspberries. Are you saying
25:56
Speaker 1: God has a favorite flavor or scent. I'm saying the
25:59
Speaker 1: universe has a smell and it's not vanilla. And it
26:01
Speaker 1: doesn't feel like nothing. It smells like everything. Yeah, exactly
26:05
Speaker 1: smells like barbecue. All right, Well, this is a pretty
26:07
Speaker 1: lofty goal. I guess what makes is this? Just think
26:10
Speaker 1: it's even possible? Like, why should the universe be reducible
26:13
Speaker 1: to a few simple equations or laws or rules. Why
26:17
Speaker 1: couldn't the universe just be kind of crazy and random? Yeah?
26:20
Speaker 1: I think simply the answer is hope. We hope that
26:23
Speaker 1: it's possible. We would love for it to be possible,
26:27
Speaker 1: and like many human projects, it's just driven by hope,
26:31
Speaker 1: not faith, you know, just hope. We would love to
26:33
Speaker 1: have an explanation for the universe that is simple and complete.
26:37
Speaker 1: We don't know why any explanation for the universe holds,
26:40
Speaker 1: Like why do science even work? Why can you do
26:42
Speaker 1: an experiment today and then tomorrow the same laws of
26:45
Speaker 1: physics still work. We don't even know why that's true. Right,
26:48
Speaker 1: So we're, you know, on sort of shaky ground philosophically.
26:51
Speaker 1: But we've made a lot of progress, right. This hope
26:54
Speaker 1: has fueled us towards a ever deeper understanding of the
26:58
Speaker 1: nature of reality and an ever simpler description. Like as
27:02
Speaker 1: we peel apart matter, we do find a smaller number
27:06
Speaker 1: of simpler objects that explain complexity at a higher level.
27:10
Speaker 1: You really only need about three particles to explain hurricanes
27:13
Speaker 1: and hamsters and lamas and all that stuff. So so
27:16
Speaker 1: far it seems to work. We've made pretty good progress.
27:19
Speaker 1: But then, Daniel, the problem is you also have to ask,
27:22
Speaker 1: is there a theory of hope? Can you explain hope
27:24
Speaker 1: for the theory? And then your brain explodes. It's a
27:27
Speaker 1: theory of inception and it's not just hope. Right, We've
27:30
Speaker 1: made some good progress, and also we have some good tips,
27:34
Speaker 1: Like we look at some numbers, and we look at
27:36
Speaker 1: some trends, and things seem to be going in the
27:39
Speaker 1: right direction. What do you mean. Well, for example, we
27:41
Speaker 1: would love to explain how all of the forces are
27:44
Speaker 1: really the same thing, you know, not that they're exactly identical,
27:48
Speaker 1: but that they're like four parts of the same thing,
27:50
Speaker 1: the way like the power rangers come together into one
27:52
Speaker 1: big ranger or whatever you call that. So we'd love
27:55
Speaker 1: to do that, and one obstacle to doing that is
27:58
Speaker 1: understanding why they're all such different strengths. Like the weak
28:01
Speaker 1: force is pretty weak, and the strong force is pretty strong,
28:04
Speaker 1: and gravity is like a crazy week. It's hard to
28:07
Speaker 1: understand how you have these four bits and fit them
28:10
Speaker 1: together if they're all such different strengths. Well, it turns out,
28:14
Speaker 1: and we talked about this on the podcast one time,
28:16
Speaker 1: that the strength of the forces depends on the energy
28:19
Speaker 1: of the experiment you use to probe them. Like the
28:22
Speaker 1: charge of the electron depends on how closely you look,
28:25
Speaker 1: how far you penetrate into this like cloud of virtual
28:28
Speaker 1: particles that surround the electron. Well, all of the forces
28:32
Speaker 1: are like that. It's called the running couplings. The value
28:35
Speaker 1: that dictates how powerful the forces depends on energy. The
28:39
Speaker 1: amazing things that as you go up in energy, all
28:42
Speaker 1: these numbers are pointing together. It seems like they're coming
28:45
Speaker 1: together to one common value. There are a lot of
28:48
Speaker 1: hints that maybe it is possible to unify everything together
28:51
Speaker 1: because things sort of leaned that way. Yeah, things are
28:54
Speaker 1: leaning that way. We think that if the universe was
28:56
Speaker 1: really hot and dense and there was a lot of energy,
28:59
Speaker 1: that all the forces would be similarly powerful the way.
29:03
Speaker 1: For example, magnetism seems weaker than electricity, right, Well, it
29:07
Speaker 1: turns out that if you're going at the speed of light,
29:09
Speaker 1: the two things have equal strength, which is why photons
29:13
Speaker 1: can exist, because they're just electricity and magnetism like slashing
29:16
Speaker 1: back and forth in perfect balance. So at the speed
29:19
Speaker 1: of light, those two forces are the same. And we
29:22
Speaker 1: think that in the very early universe, or at very
29:24
Speaker 1: hot dense environments, the strong force, the weak force, electromagnetism,
29:29
Speaker 1: and maybe even gravity all have the same strength, which
29:33
Speaker 1: would help us fit them together into sort of like
29:36
Speaker 1: one big idea. All right, interesting, Well, I guess maybe
29:39
Speaker 1: let's go into now what are some of the leading
29:42
Speaker 1: candidates for this theory of everything. I know that there
29:45
Speaker 1: are a couple of ideas out there. Some are fringe,
29:48
Speaker 1: some are more mainstream and a lot of people seem
29:50
Speaker 1: to know about. So what are some of these leading
29:53
Speaker 1: candidates for the universe's total Well, there's definitely one that's
29:57
Speaker 1: far out ahead of everybody else in terms of like
30:00
Speaker 1: a number of people who were investing their careers in
30:03
Speaker 1: it and believing like it might actually lead to a
30:05
Speaker 1: theory of everything. And that's definitely string theory. Yeah, that's
30:09
Speaker 1: the one with the best PR department too. It seems
30:11
Speaker 1: like a lot of people had heard of the string
30:13
Speaker 1: theory exactly. A lot of people have written really beautiful
30:16
Speaker 1: popular science books on it, and there's lots of specials
30:19
Speaker 1: about it, and people talk about it. It's also sort
30:21
Speaker 1: of cool and it's easy to sort of visualize because
30:25
Speaker 1: it tells you that the universe it's not made out
30:28
Speaker 1: of these weird tiny dots that are hard to get
30:31
Speaker 1: your mind around, but instead that it's made out of
30:33
Speaker 1: these little vibrating strings. And now these little strings, are
30:37
Speaker 1: they like part of a field? Are they just like
30:39
Speaker 1: strings floating in space? Are they part of a giant
30:43
Speaker 1: like universe? You know, guitar or what? Are these strings?
30:47
Speaker 1: So there are quantum objects, right, So in that sense,
30:50
Speaker 1: you can think of this as a quantum field theory, right,
30:53
Speaker 1: and these little strings instead of saying, like, you know,
30:56
Speaker 1: a little energy located in a point in a field
30:59
Speaker 1: instead of matter, gin like a one dimensional version of
31:03
Speaker 1: a particle instead of a zero dimensional version. Imagined a
31:06
Speaker 1: one dimensional version of a particle. That would be a line,
31:09
Speaker 1: And then this thing can vibrate. You can have different
31:11
Speaker 1: kinds of energy. And the cool thing is that if
31:13
Speaker 1: you look at these strings from really really far away,
31:16
Speaker 1: they look like particles because you can't sort of like
31:18
Speaker 1: see how wide they are. But if you zoom in,
31:21
Speaker 1: you would discover that all the things we call different
31:23
Speaker 1: particles are just the same string vibrating different ways, like
31:27
Speaker 1: vibrates this way you get an electron, vibrates that way
31:30
Speaker 1: you get a graviton. So you're saying, like all quantum
31:33
Speaker 1: particles like a cork or an electron. If you zoom
31:37
Speaker 1: in enough at the core of it instead of a
31:39
Speaker 1: point particle, you'll see like a little what vibrating though,
31:42
Speaker 1: And how can it be one dimensional if the electron
31:45
Speaker 1: and the cork are multi dimensional? Well, in our current theory, right,
31:49
Speaker 1: electrons and quirks are zero dimensional. They're just point particles
31:52
Speaker 1: that have no length, no width, no height, and so
31:56
Speaker 1: that's kind of bonkers. It doesn't make any sense. You know,
31:59
Speaker 1: how can you have mass with no volume? It would
32:01
Speaker 1: have infinite density and you know, turn into a black
32:03
Speaker 1: hole and all that stuff. We dug into that whole
32:06
Speaker 1: thing in another podcast episode. So this just takes it
32:08
Speaker 1: and stretches it out and makes it one dimensional. Says
32:11
Speaker 1: it has length but no width and no height, and
32:14
Speaker 1: then it can vibrate because that string can move because
32:17
Speaker 1: the quantum field itself can oscillate. Right, but is it
32:20
Speaker 1: vibrating in any particular dimension or direction or is this
32:24
Speaker 1: in like another dimension it's vibrating. Yeah, So the mathematics
32:27
Speaker 1: that string theory are complicated, but it turns out that
32:30
Speaker 1: they work best if space has more dimensions than just
32:34
Speaker 1: the three that we're familiar with. If it has like
32:37
Speaker 1: eleven dimensions and these other extra spatial dimensions would be
32:41
Speaker 1: sort of very hard for us to see. That would
32:43
Speaker 1: be very very small. So it's kind of difficult to
32:46
Speaker 1: have visualize. But imagine like every location in space, right, X, Y,
32:50
Speaker 1: and Z those are the three dimensions. Now at every location,
32:53
Speaker 1: you can also like go around, or you can like
32:56
Speaker 1: turn or there's like another direction, another dimension of your location,
33:01
Speaker 1: another value you need to specify to say exactly where
33:04
Speaker 1: you are. Interesting. So it's reducing quantum theory to like
33:09
Speaker 1: little string theory. Yeah, exactly, and then these strings oscillate
33:14
Speaker 1: often in these other hidden dimensions. Now, there are some
33:18
Speaker 1: theories of extra dimensions of space and time in which
33:21
Speaker 1: those dimensions are very simple. They're just like little loops,
33:24
Speaker 1: and those are fun. We've talked about them on the podcast.
33:26
Speaker 1: String theory requires these extra dimensions to be really complicated.
33:30
Speaker 1: Objects are called callaby Yaw manifolds. They would have very
33:34
Speaker 1: very complicated geometries and anyway, the strings would like vibrate
33:37
Speaker 1: in these crazy dimensions that would be invisible to us,
33:41
Speaker 1: but based on their vibration in those dimensions, they would
33:43
Speaker 1: appear different to us. So if it vibrates, you know,
33:46
Speaker 1: this way all those other dimensions, then it would be
33:49
Speaker 1: an electronic vibrates that way, it would be a muan,
33:51
Speaker 1: and that would be pretty awesome to understand. Like, oh,
33:54
Speaker 1: electrons and muans. They look like one is a copy
33:57
Speaker 1: the other one. That's because one is like the reds
34:00
Speaker 1: of the other one, or it's you know, a different
34:02
Speaker 1: standing wave of this vibrating string in this other dimension.
34:05
Speaker 1: It would help us unify those things and understand, like
34:08
Speaker 1: the relationships we see in the particles are actually just
34:12
Speaker 1: different modes of those strings. Is it kind of like
34:14
Speaker 1: you know, how different sheets of paper look all the
34:17
Speaker 1: same from the side, but maybe if you look at
34:19
Speaker 1: them from another dimension, they could have different shapes and colors. Yeah. Absolutely.
34:24
Speaker 1: Or if you're a two dimensional object in the three
34:26
Speaker 1: dimensional world, the stuff that's happening that third dimension can
34:29
Speaker 1: definitely affect what you see and you just aren't privy
34:32
Speaker 1: to it, and so you're seeing a little slice of
34:35
Speaker 1: what's going on, and you can't understand the relationships between
34:37
Speaker 1: those things because they exist in a dimension that you
34:40
Speaker 1: can't move in or you can't see. But string theories
34:43
Speaker 1: also it's just sort of beautiful mathematically, like it all
34:46
Speaker 1: really fits together very nicely, and a lot of people
34:49
Speaker 1: are really attracted to it because some certain things just
34:51
Speaker 1: sort of like fall out of the theory. For example,
34:54
Speaker 1: string theory is a very natural theory of quantum gravity.
34:58
Speaker 1: You basically have to have grab in your theory. If
35:01
Speaker 1: you have a string theory, interesting, it really pulls out
35:03
Speaker 1: your heart strings. That's what you're saying. All right, let's
35:06
Speaker 1: get into what some of the other leading candidates are
35:09
Speaker 1: and let's talk about which one seems the most promising
35:12
Speaker 1: out of these promising candidates. But first, let's take another
35:16
Speaker 1: quick break. All right, we're talking about the theory of everything,
35:32
Speaker 1: or at least a couple of theories of Everything's and
35:35
Speaker 1: talked about string theory as one of the most popular ones.
35:38
Speaker 1: But there are a couple of other theories that are
35:40
Speaker 1: up there, right. They're still in contention for everything, for
35:43
Speaker 1: the hole shabangba exactly. So what are some of these theories.
35:48
Speaker 1: One of my favorite is sort of a generalization of
35:50
Speaker 1: string theory. String theories and idea that's been around for
35:53
Speaker 1: decades and people were poking around making progress, and they
35:56
Speaker 1: were like a few kinds of string theory that had
35:58
Speaker 1: been developed, and they only described like a little bits
36:00
Speaker 1: of the universe, or there was this kind of string
36:02
Speaker 1: theory of those kind of strings and how they interacted.
36:04
Speaker 1: The field was sort of fracturing to several different ideas.
36:08
Speaker 1: Then in Ed Witten, is like one of the smartest
36:11
Speaker 1: people ever, unified them all together. He showed that all
36:15
Speaker 1: the different string theories that people have been working on.
36:17
Speaker 1: We're really just like sort of limiting cases that were
36:20
Speaker 1: like extreme versions of one grander theory. So we had
36:23
Speaker 1: these like five different string theories and he brought them
36:26
Speaker 1: together into one theory that he called M theory, like
36:30
Speaker 1: the multi string guitar theory of string theory exactly. And
36:33
Speaker 1: you know, nobody knows why it's called M theory. And
36:37
Speaker 1: eventually somebody asked him like, hey, Ed, why did you
36:39
Speaker 1: call this thing M theory? What does M stand for?
36:41
Speaker 1: He said, well, actually he didn't know when he was
36:43
Speaker 1: waiting for us to like really deeply understand it and
36:45
Speaker 1: then we could figure out what M stood for. I
36:48
Speaker 1: think he really just wanted to say my theory. It's
36:52
Speaker 1: my theory, and like I'll just hide it as a
36:55
Speaker 1: physics nomenclature maybe or since his last name starts with
36:59
Speaker 1: a W, maybe like has a secret upside down W
37:02
Speaker 1: in there. Uh. Interesting, Like the anti version of him
37:05
Speaker 1: came up with this theory exactly right, And so M
37:08
Speaker 1: theory is sort of like a super version of string
37:11
Speaker 1: theory and includes other things like supersymmetry, this idea that
37:15
Speaker 1: every particle that's a fermion, like the matter particles have
37:18
Speaker 1: relationship with all the bosons the fourth particles, and for
37:22
Speaker 1: every boson there should be a fermion. For every fermion
37:24
Speaker 1: there should be a boson. So it brings that together
37:27
Speaker 1: also into one larger theory. Instead of just thinking about
37:30
Speaker 1: individual strings, this allows us to think about like two
37:33
Speaker 1: dimensional versions that they call brains, which is short for membrane,
37:38
Speaker 1: not like b our ai in your brain. Right, Like
37:42
Speaker 1: maybe things aren't strings, but they're like little and nap
37:45
Speaker 1: can cost, right, yeah, like little sheets or three or
37:48
Speaker 1: four dimensional. And so they have these arbitrarily dimensional objects,
37:53
Speaker 1: you know, one dimensional, two dimensional, three dimensional, and so
37:55
Speaker 1: they call them about this rather ridiculous name P for
37:58
Speaker 1: the number of dimensions, and then P brain the dump dump,
38:02
Speaker 1: that's a P brain theory. Then it really is a
38:04
Speaker 1: P brain theory. But you hear these like super smart
38:07
Speaker 1: people really talking to each other about P brains, you know,
38:10
Speaker 1: without any irony or giggles. It's good thing they didn't
38:13
Speaker 1: call it the opposite brain P brain P theory. Well,
38:16
Speaker 1: you know, there are a lot of people out there
38:18
Speaker 1: who don't think that string theory is the path towards
38:21
Speaker 1: a theory of everything. They think it's ridiculous waste of
38:24
Speaker 1: time and all just sort of mathematical conjecture. They're like
38:27
Speaker 1: theory and everything that's a theory of nothing. Yeah, exactly. Well,
38:30
Speaker 1: the real criticism of string theory is that it operates
38:33
Speaker 1: at such a tiny level that we can't really test it. Like, sure,
38:37
Speaker 1: you're telling us maybe what's happening at tend to the
38:40
Speaker 1: minus thirty five meters, but how do we know. We
38:42
Speaker 1: don't have a collider that can do experiments yet at
38:45
Speaker 1: that small scale, and so it's just sort of like
38:48
Speaker 1: a story we're telling, but not something we can test. Really.
38:51
Speaker 1: The only test of string theory so far has been
38:54
Speaker 1: a search for these super symmetric particles, these extra fermions
38:59
Speaker 1: and bosons that might be there to balance on the
39:01
Speaker 1: ones we have in the standard model, and we were
39:04
Speaker 1: supposed to find those at the Large Jhon Collider, but
39:07
Speaker 1: we didn't. We didn't see any supersymmetric particles. So that's
39:11
Speaker 1: a bit of a blow for string theory. All right. Well, then,
39:13
Speaker 1: if strings or little napkins or key brains are not
39:17
Speaker 1: maybe the best way to go, what's an alternative? Then well,
39:20
Speaker 1: some people are coming at it from a completely different
39:21
Speaker 1: direction instead of taking quantum mechanics and trying to incorporate
39:26
Speaker 1: gravity and making this big quantum mechanical string theory view
39:29
Speaker 1: of the universe. They're starting from gravity, and they're saying,
39:33
Speaker 1: instead of making gravity into a quantum theory, let's just
39:36
Speaker 1: try to quantize space itself, like you were talking about
39:39
Speaker 1: earlier space and time or fundamental elements of the universe.
39:42
Speaker 1: We don't really know if that's true, if these things
39:45
Speaker 1: come out from something smaller. We don't understand what space is.
39:48
Speaker 1: So a lot of people are working on this theory
39:50
Speaker 1: called loop quantum gravity, which tries to take space and
39:54
Speaker 1: describe it as these little bits of like a quantum foam,
39:57
Speaker 1: and I have the whole universe sort of come out
39:59
Speaker 1: of the quantum foam, like instead of having a like
40:02
Speaker 1: a perfectly smooth universe and space and time on which
40:07
Speaker 1: you have these quantum fields that are lumpy. Maybe space
40:10
Speaker 1: itself is kind of crunchy and lumpy and not perfectly smooth. Yeah,
40:14
Speaker 1: maybe there's like a minimum distance to the universe below
40:17
Speaker 1: which it doesn't really make sense to talk about things
40:20
Speaker 1: being closer together than that, because it's just not possible.
40:23
Speaker 1: Like all of spaces like pixels on some universe screen
40:27
Speaker 1: and so that's exciting and people have been working on
40:30
Speaker 1: that the last few decades. There's been some advances and revolutions,
40:33
Speaker 1: and it seems sort of like as an alternative to
40:36
Speaker 1: string theory because it's a different way you might be
40:38
Speaker 1: able to bring gravity and quantum mechanics together. It's a
40:42
Speaker 1: completely different approach and it's made some progress. But the
40:45
Speaker 1: problem is that it's sort of just brings gravity and
40:48
Speaker 1: quantum mechanics together. It doesn't actually unify all of the forces,
40:51
Speaker 1: Like it can't explain why do we have electromagnetism, why
40:55
Speaker 1: do we have the weak force? Why do we have
40:56
Speaker 1: the strong force? But it's you know, progress in that direction, right,
41:00
Speaker 1: I guess you can if you you know, make space
41:02
Speaker 1: itself quantum. Then that doesn't explain how what like particles
41:06
Speaker 1: can interact with each other across the distances. Is that
41:09
Speaker 1: kind of the limitation. It's not really a limitation, it's
41:11
Speaker 1: just like they haven't gotten there yet. They're still building
41:14
Speaker 1: the foundational building blocks. It's not clear necessarily how you
41:17
Speaker 1: would get there. It's not ruled out, it's not impossible,
41:20
Speaker 1: but so far the scope of loop quantum gravity is
41:22
Speaker 1: not to describe all of it is just to make
41:25
Speaker 1: this step of bringing gravity and quantum mechanics together. Once
41:29
Speaker 1: you do that, you can collect your five note about prizes,
41:31
Speaker 1: you know, take a day off, and then you can
41:33
Speaker 1: start working on the other part of the theory. Right well,
41:35
Speaker 1: so those are some of the respectable toes, you know,
41:38
Speaker 1: that's the big toe, the middle toe of physics, his
41:41
Speaker 1: feet and feet. But there are also sort of like
41:44
Speaker 1: these less respectable toes or you know, kind of the
41:48
Speaker 1: pinky toes of the universe floating out there, the theories
41:51
Speaker 1: that are not quite as popular or mainstream, but that
41:54
Speaker 1: might be exciting. So Daniel real Quick tells, what are
41:57
Speaker 1: some of these fringe theory right well, theories of everything
42:00
Speaker 1: are a popular target for people who are not in academia,
42:03
Speaker 1: who think like maybe the physicists have just sort of
42:05
Speaker 1: gotten it wrong, and what it needs is like a
42:07
Speaker 1: fresh idea from somebody who's not entrenched in all of
42:10
Speaker 1: these ideas and the history on the incremental progress, coming
42:14
Speaker 1: in with a brand new idea and blow it all up.
42:17
Speaker 1: And so, for example, Steve Wolfram came out last year
42:20
Speaker 1: with the theory that he thought might be like the
42:22
Speaker 1: foundations of a theory of everything. He's a smart guy.
42:25
Speaker 1: He's a guy who developed mathematica, and he is a physicist,
42:27
Speaker 1: has a degree in physics. And his basic idea, which
42:30
Speaker 1: we dug into once on the podcast, is that maybe
42:33
Speaker 1: the universe is made out of these cellular automata. He
42:37
Speaker 1: envisions that the universe is made out of one kind
42:40
Speaker 1: or a small set of kinds, of tiny things with
42:43
Speaker 1: very simple rules. And he studied this for a long
42:45
Speaker 1: time and shown, and many other people have shown that
42:48
Speaker 1: if you start from simple things with simple rules, you
42:51
Speaker 1: can get complexity. And we know that already, like hurricanes
42:55
Speaker 1: are not written into the laws of the universe. They
42:57
Speaker 1: arise from corks and electrons into being in really complicated ways.
43:01
Speaker 1: So what he did was he showed that, you know,
43:03
Speaker 1: you can sort of have like cellular automata that right
43:06
Speaker 1: the rules of the universe. You start from a few
43:10
Speaker 1: simple ideas and then a rule for how those ideas
43:12
Speaker 1: can change. They can sort of like write the rules
43:14
Speaker 1: of the universe. And he looked at what his cellular
43:17
Speaker 1: automatic produced and they sort of looked physics ee, and
43:20
Speaker 1: he was like, ah, look at this, maybe this is
43:22
Speaker 1: how the universe was generated. All right. So that's one
43:25
Speaker 1: kind of a fringe idea that you know, maybe you
43:28
Speaker 1: can make a universe at a very simple building blocks cells.
43:32
Speaker 1: What are some of the other fringe theories. Well, there
43:34
Speaker 1: were a couple of engineers who took it upon themselves
43:37
Speaker 1: to write a theory of everything. This is a theory
43:40
Speaker 1: that's called the Fragments of Energy theory by two guys
43:43
Speaker 1: in North Carolina called Silverberg and Icean, And they were
43:47
Speaker 1: thinking about energy and they're noticing that like energy seems
43:50
Speaker 1: to flow, doesn't ever just sort of like hang out.
43:53
Speaker 1: And they thought, well, you know, maybe energy is the thing,
43:56
Speaker 1: and like energy always flows through the universe, and you
43:59
Speaker 1: can think about it flowing through these lines, and maybe
44:01
Speaker 1: you can quantize it and like break it up and
44:03
Speaker 1: need these little packets and think about how it flows together.
44:07
Speaker 1: So they wrote down some rules for how energy flows
44:09
Speaker 1: and how to break it up and how these packets
44:11
Speaker 1: of energy would then interact, and they were able to
44:14
Speaker 1: do some cool stuff with it, Like they twisted it
44:17
Speaker 1: a little bit and added a few bits, and they
44:19
Speaker 1: were able to reproduce some predictions of general relativity. So
44:23
Speaker 1: they thought that was pretty cool, and they put this
44:26
Speaker 1: out there to quite a lot of fanfare. Actually it
44:29
Speaker 1: hasn't landed very convincingly, Like I think most of academic
44:32
Speaker 1: physics was like, yeah, that was a paper review, review
44:37
Speaker 1: or number one says maybe her number two days And
44:41
Speaker 1: is that the most hurtful review you can get in physics,
44:44
Speaker 1: Like not something dissecting your math or telling you why
44:47
Speaker 1: your hypothesis is wrong. Is it's a difference you could
44:50
Speaker 1: imagine revising general relativity or like reimagining it in some
44:54
Speaker 1: different conceptual space and reproducing it. That's cool, But it's
44:58
Speaker 1: not like a new theory of everything. So I haven't
45:00
Speaker 1: really like made any progress. In fact, their theory doesn't
45:04
Speaker 1: quite reproduce general relativity. They need to like add some
45:07
Speaker 1: by hand numbers to squeeze it in there to get
45:10
Speaker 1: things right, like you know, the procession of mercury and
45:12
Speaker 1: the bending of light around the sun. Stuff Einstein got
45:15
Speaker 1: right a hundred years ago without having to tweak or
45:17
Speaker 1: tune his theory at all. They got to sort of
45:19
Speaker 1: like put this in a little bit by hand. So
45:21
Speaker 1: it's not really clear that it's progress. It's not like
45:24
Speaker 1: a way forward. It's just like, here's another way of
45:26
Speaker 1: looking at general relativity. That makes more sense to us,
45:30
Speaker 1: and also doesn't quite work as well, so not necessarily
45:33
Speaker 1: like really that exciting. It doesn't seem inevitable or a
45:36
Speaker 1: shoe in right away, and it also doesn't necessarily tell
45:39
Speaker 1: you what to do next. Like the exciting thing about
45:41
Speaker 1: string theory is that the thing is to explore their
45:44
Speaker 1: puzzles to solve. They're like, oh, we can try this
45:47
Speaker 1: different compactification of those other dimensions. We can try this one,
45:49
Speaker 1: we can try that one. There's areas where you can
45:51
Speaker 1: make progress here. It's just sort of like, oh, that's interesting.
45:54
Speaker 1: I'm not sure what to do next with this. What
45:56
Speaker 1: are some other fringe theories? So another one that got
45:59
Speaker 1: a lot of attention was going to buy a guy
46:00
Speaker 1: named Eric Weinstein. He also has a PhD in physics,
46:04
Speaker 1: but now it works at a hedge fund, and he's
46:06
Speaker 1: a you know, very well known guys on podcasts all
46:09
Speaker 1: the time, and he has a theory called geometric unity
46:12
Speaker 1: that he came out with about ten years ago. And
46:15
Speaker 1: he basically just takes all the theories that we have
46:17
Speaker 1: now and sort of stacks them on top of each other,
46:20
Speaker 1: sort of like an ice cream sandwich and says, I'm
46:23
Speaker 1: just gonna stick them all into one container. What do
46:25
Speaker 1: you mean, like quantum gravity, like quantum physics and general activity,
46:30
Speaker 1: you can stack them. Well, he doesn't have quantum gravity
46:32
Speaker 1: in there yet, and so he's just taken all the
46:34
Speaker 1: quantum theories and stacked those together. And you know, like,
46:38
Speaker 1: I'm not really sure way you accomplished in doing that.
46:41
Speaker 1: It's just sort of like groups them. It doesn't necessarily
46:43
Speaker 1: like show that they're part of one larger hole or
46:47
Speaker 1: that they have a deep relationship. He likes the way
46:49
Speaker 1: they've stuck together, but there's no simplification that's achieved there
46:53
Speaker 1: in my understanding, I see, it's still pretty unsupported, I guess.
46:56
Speaker 1: And another issue with it is that he hasn't yet
46:59
Speaker 1: written a paper about it. So it's been out there
47:01
Speaker 1: for about ten years. And he was invited to give
47:03
Speaker 1: a talk about it at Oxford, and he came and
47:05
Speaker 1: he presented it. The problem is that like nobody invited
47:08
Speaker 1: all the physicists at Oxford and so, and that hurt
47:12
Speaker 1: your feelings. So now you're just down on the theory. No,
47:15
Speaker 1: And in academia, you know, we need to see a paper,
47:17
Speaker 1: We need to like see all the detailed description so
47:20
Speaker 1: we can think about it and play with it and
47:22
Speaker 1: read about it and talk to each other about it.
47:24
Speaker 1: And he's actually recently promised to put a paper out.
47:27
Speaker 1: Maybe they asked him why why did those and he
47:29
Speaker 1: write a paper and he just said, and you're like, oh,
47:32
Speaker 1: you got us, you got us. And other mathematicians that
47:35
Speaker 1: have looked at what he said sort of digested what
47:37
Speaker 1: he said a podcast and in his one presentation has
47:40
Speaker 1: said that they found it mathematically inconsistent. You know, there
47:43
Speaker 1: are reasons why we haven't stacked all these theories together.
47:46
Speaker 1: They don't play nicely together. There are anomalies, there are
47:49
Speaker 1: things that don't make sense. They're inconsistencies that happen if
47:51
Speaker 1: you try to jam them together and you don't find
47:53
Speaker 1: the right way to do it. It doesn't seem like
47:55
Speaker 1: he solved those problems. But we'll just have to wait
47:57
Speaker 1: to see what his paper says. All right, Well, those
48:00
Speaker 1: are some pretty interesting and promising fringe theories, and we
48:03
Speaker 1: also have some core, more popular theories. I guess just
48:07
Speaker 1: two sort of close us out here. Daniel, Let's talk
48:09
Speaker 1: about really quick about whether or not you think it's
48:12
Speaker 1: even possible to have a theory of everything, and even
48:16
Speaker 1: if we find one, would it be useful at all
48:18
Speaker 1: in helping us in our everyday lives. You know, it
48:21
Speaker 1: might not have immediate engineering applications, right, even if you
48:25
Speaker 1: understood the universe and its smallest scale and all its
48:28
Speaker 1: littlest rules, that wouldn't help you understand when a hurricane
48:32
Speaker 1: was coming, or you know how to get to the
48:34
Speaker 1: neighboring galaxy necessarily. On the other hand, it might reveal
48:38
Speaker 1: something deep and fundamental about the universe that would give
48:41
Speaker 1: us immediate applications, if you like, uncovered a new force,
48:45
Speaker 1: or let us tap into and control dark energy, the
48:48
Speaker 1: biggest fraction of the energy budget of the universe, that
48:51
Speaker 1: could very much really change our lives. We never know
48:54
Speaker 1: what this understanding will reveal, I mean, their hand. It
48:57
Speaker 1: could allow us to create terrible weapons, and then we
48:59
Speaker 1: could wipe each other out, So you never know what
49:01
Speaker 1: the future holds. Could be useful, It could destroy all
49:03
Speaker 1: of humanity, you know, we don't. We don't really like
49:06
Speaker 1: to think about those practical consequences. Yeah, exactly, from the
49:10
Speaker 1: worst possible outcome to we are now masters of the universe. Basically,
49:14
Speaker 1: that's the spectrum we're talking about here. Then you just
49:16
Speaker 1: blame the engineers and politicians. Exactly. I was just eating
49:21
Speaker 1: some ice cream. It wasn't my fault. How was just
49:23
Speaker 1: sitting here snacking on ice cream and being flower gas
49:27
Speaker 1: did and all of a sudden, we're all dead. And
49:28
Speaker 1: if that worries you, you you know, there are people who
49:30
Speaker 1: argue that maybe it's impossible. You know, there's this famous theorem,
49:34
Speaker 1: this Godal's incompleteness theorem that says that all mathematical systems
49:38
Speaker 1: are either inconsistent or incomplete. You know that either they
49:42
Speaker 1: contradict themselves or there are things that cannot be proven.
49:46
Speaker 1: What what is this theory based on? How can it
49:49
Speaker 1: say that everything is wouldn't it also be inconsistent itself?
49:54
Speaker 1: Oh man, we need a whole another podcast episode to
49:56
Speaker 1: dig into goals in completeness theorem. So let's put a
49:59
Speaker 1: pin in that. But it's a formal theorem and mathematics,
50:02
Speaker 1: which people think is right. You can argue about what
50:05
Speaker 1: exactly it applies to and whether it applies to physical
50:07
Speaker 1: theories or just two axiom based mathematical systems. But some
50:11
Speaker 1: people use as an argument to say, like, maybe there's
50:14
Speaker 1: a limit to how well our mathematics can describe the universe.
50:18
Speaker 1: You know. It doesn't say that the universe isn't physical
50:21
Speaker 1: or doesn't make sense. But maybe, like our mathematical systems,
50:25
Speaker 1: which are based on these axioms, are just not the
50:27
Speaker 1: right language for exploring the universe. You know, it's not
50:30
Speaker 1: guaranteed that the universe can be described by mathematics just
50:34
Speaker 1: because that's the way we like to think about it currently.
50:36
Speaker 1: So what would it be. I guess we can talk
50:38
Speaker 1: about it at another time. But if not math, then
50:41
Speaker 1: what I don't know. We'll have to meet those alien
50:43
Speaker 1: physicists that have developed something else. What's the foundation, what's
50:46
Speaker 1: the language of their physical theories? Maybe it's not mathematics, right,
50:50
Speaker 1: just because we can't imagine it doesn't mean it's not reality,
50:53
Speaker 1: all right, And like you said, it might not even
50:55
Speaker 1: be possible to confirm these theories in the end, right,
50:58
Speaker 1: because we're talking about scale for which we really don't
51:01
Speaker 1: have a microscope to go and check that's right. Yeah,
51:04
Speaker 1: until we build a solar system sized particle collider, you know,
51:08
Speaker 1: send in your checks, we can't really test these theories.
51:10
Speaker 1: And it might be that it just keeps going on forever,
51:13
Speaker 1: Like you might find what do you think is the
51:14
Speaker 1: smallest theory, but it just keeps going down and down
51:18
Speaker 1: the rabbit hole exactly. It might be that there is
51:21
Speaker 1: no smallest scale and that there's just like an infinite
51:24
Speaker 1: layers to this onion. Hey, that's an idea onion ice cream.
51:28
Speaker 1: Maybe that's the unifying theory of everything, Daniel the infinite
51:32
Speaker 1: onion flavored ice cream. Wow, I'm flabbergasted. And while it's
51:37
Speaker 1: fun to think about the theories of physics, that sort
51:39
Speaker 1: of physicists are thinking about a lot of people out
51:42
Speaker 1: there thinking about theories of everything, and sometimes they email
51:45
Speaker 1: them to me. I got an email from one of
51:47
Speaker 1: our listeners who had a fun idea. He says, quote,
51:50
Speaker 1: maybe our observable universe is actually the nexus of two
51:54
Speaker 1: different overlapping universes, one for quantum mechanics and one for
51:58
Speaker 1: general relativity, and that's why we can't unify them. So
52:02
Speaker 1: it's interesting. Yeah, it's fun to think about, and it's
52:04
Speaker 1: sort of tantalizing because everybody knows this is a big
52:07
Speaker 1: goal in physics and physicists that are struggling to get there,
52:10
Speaker 1: and it would be fun to sort of like have
52:12
Speaker 1: that moment of inspiration and see the truth of the universe,
52:15
Speaker 1: and then you know, reveal it to everybody and eat
52:17
Speaker 1: to my scream while you win your Nobel prize. Then
52:19
Speaker 1: you can be flavor gasted and live in the halls
52:22
Speaker 1: of truth. That's what we all aim for. I think
52:25
Speaker 1: that should be the name of our ice cream pop
52:26
Speaker 1: up stand, flavor Gasted. Let's do it all right, Well,
52:30
Speaker 1: hopefully we'll make some progress in the future. In the meantime,
52:34
Speaker 1: try not to stop your toes, Daniel, and don't eat
52:36
Speaker 1: too much ice cream. Well, we hope you enjoyed dad.
52:38
Speaker 1: Thanks for joining us, see you next time. Thanks for listening,
52:49
Speaker 1: and remember that Daniel and Jorge Explain the Universe is
52:52
Speaker 1: a production of I Heart Radio. For more podcast For
52:56
Speaker 1: my Heart Radio, visit the i heart Radio app, Apple Podcasts,
53:00
Speaker 1: or wherever you listen to your favorite shows.