March 7, 2024 • 53 mins
Daniel talks to Matt Strassler about how everything is vibrating, and his new book "Waves in an Impossible Sea" (Part 2)
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Speaker 1 (00:08):
Hello everyone. Quick note that this episode is part two
of my conversation with theoretical physicist Matt Stressler about his
new book Waves in an Impossible Scene. If you haven't
yet heard part one, pause this episode and go back
listen to the first part. This stuff is hard enough
without listening to it backwards, so do the first things first.
(00:30):
Pause this episode and come right back. We'll wait for you. Hi.
I'm Daniel. I'm a particle physicist and a professor at
(00:53):
UC Irvine, and welcome to the podcast. Daniel and Jorge
explain the Universe, in which we dig deep into the
nature of space and time and particles, in which we
want you to understand our new ideas about how the
universe works and be bewildered with us about everything we
don't understand about the universe. Today we have an unusual episode,
(01:14):
and then it's part two. This is the second half
of my conversation with Professor Matt Stressler. In the first
part of the conversation, we reviewed relativity. How waves travel
through media, but light waves seem to travel through empty space.
How you can measure the speed of most waves like sound,
relative to their medium, but you can't measure the speed
(01:37):
of light relative to space, only to other things in space.
Matt is painting us a careful and insightful picture of
how everything is made out of waves, and why that's
crucial to understanding the last, the craziest, the most recent
wave to be discovered, waves in the Higgs field. So
(01:58):
here is part two of my conversation with Matt. Give
us a glimpse of how your mind works, how you
see the universe as being built out of waves, and
why you think this is so important for understanding the
Higgs field.
Speaker 2 (02:13):
I'll take you through that in a few steps, but
the most important to start with is we have to
deal with words. And this is a theme of the
book because I think it's a theme of human affairs
in general, and it's certainly a theme of scientific communication.
Speaker 1 (02:32):
Oh absolutely, And physics is terrible about words. I mean,
we use names for things totally inappropriately. Quarks have color
and flavor, Like, what are we talking about here? Why
don't we just invent new words to describe new things? Right?
Speaker 2 (02:45):
And we used to? I mean, you know, this is
in some sense of mid twentieth century development. But that said,
in order to think about things ourselves, we often borrowed
words from English, and particle is one of them. Wave
is another force, even theory. We have lots of words
that are part of physics dialect that we have taken
(03:08):
from English. And we humans, just in ordinary language, are
spectacularly good at using a single word with many definitions,
right we all know. You go to the dictionary and
you look up simple words and there's twelve definitions of
the same word. And yet in language we communicate with
each other switching definitions all the time. We may use
the same word in one sense in two different ways
(03:29):
and it doesn't bother us. Well, this is true of
physicists as well. We have our dialect, some words have
multiple meanings. We switch back and forth without a problem.
But of course, when you are switching dialects, when you
are trying to communicate physics to a non physics speaking
English speaker, just as when you try to switch from
French to English and you're trying to use words that
(03:52):
have multiple meanings without even thinking about it, you may
easily confuse your listener. And we do this all the time.
So they are famous phrases like an electron is part particle,
part way, it's a wave, part of the time, and
it's a particle part of the time. And aside from
the fact that that could mean many different things, and
(04:12):
over history it has meant at least two different things
to two different classes of people. It's really problematic that
the word particle has multiple meanings and the word wave
has multiple meanings, and the most common meanings in English
are not the ones that we are using here. So
we will not get anywhere if I don't spend a
minute on those definitions. So I'll start with wave. We'll
(04:35):
talk about waves for a while, because waves are such
a wonderful phenomenon. They underlie so many aspects. Obviously, I'm
the sound I'm using to communicate and the radio waves
that we're using to send all this information back and forth.
And also they're the fundamentals in music, just surrounded by
music in our modern world in the best and we're
senses and we should take a moment to think about
(04:56):
what we mean. And one thing we do not mean
is the thing that everybody means when they go to
the beach. Right, you go to the beach, Oh, that
is a great wave. I want to serf that one. Ooh,
here comes a big wave. Okay, what do we mean.
We mean, here comes a big crest in the water,
a big high point in the water, and it is
separated from the next high point by two low points,
(05:20):
and we call that crest a wave. That is not
what we are talking about here. We are not made
from single wave crests. No. Yet, the word wave as
used in science is a rich concept. There are waves
of many different shapes and sizes. For example, I'm speaking
now making sound waves, or if you're a recording engineer,
(05:42):
you will say I'm making a sound wave singular. So
a wave can be a very complicated shape. But to
keep things focused, let's talk about the simplest waves. And
the simplest waves are the ones that you make when
you sing. You sing a note, or you make a
pure tone on a musical instrument, and then you are
(06:03):
making a wave which consists of a whole bunch of
high points and a whole bunch of low points, a
whole bunch of crests and troughs equally spaced, and it
may be a long series of them.
Speaker 1 (06:14):
So imagine like a sine wave extending all the way
from negave infinity to positive infinity along the x axis
or something.
Speaker 2 (06:20):
If you like your tenth grade, eleventh grade math, Yes exactly,
or if you don't, it's just the ripples that you
would make in a pond. If you put your hand
in the water and moved it up and down regularly,
you would get a set of ripples. It would move outward.
That's a wave in science rather than a set of waves.
So it's more what a beach gore would call a
wave set or a wave train. And now even that
(06:43):
has a subtlety which I'll come back to you. But
of the types of waves that we encounter which scientists
talk about, there are two types, both of which are
really important and which have slightly different properties. And the
first one is the one that you would talk about
when you're talking about sound waves most of the time
from my voice to your ears. Those are traveling waves,
(07:04):
traveling meaning, as you would guess, they're moving in a
certain direction at a certain speed. And traveling waves include sound,
they include ocean waves, they include the seismic waves which
across the earth. They include light waves which cross the universe,
and they include the things we call particles and when
they're moving around. And the other type of wave that
(07:25):
we encounter is standing waves and standing waves have crests
and troughs that don't go anywhere. They just sort of
vibrate in place. So a classic example would be the
way in which a guitar string or a violin string
vibrates pluck it. It goes up and down and up
and down and up and down. There's a crest where
(07:47):
it bends upward, and then a moment later it's a
trough where it bends downward, and it goes up and
down and up and down and up and down. Or
maybe the air vibrating in an organ pipe. When you
make the organ pipe sound, what you're doing is you're
making the air inside ripple back and forth where it's
more dense in one place and then less dense, and
(08:07):
it goes back and forth and back and forth in
a regular repeating fashion. But it's not actually moving outside
the organ pipe. It's staying in the organ. OK. So
we have these two different types of waves, traveling waves
which move around, standing waves which they put and in
the case of traveling waves, as I described, it's not
a single wave crest, it's a whole set of them.
(08:28):
With standing waves, it can be any number of crests,
including just one. So it's still not a wave at
the beach because the wave of the beach is moving.
But it can be as simple as a wave at
the beach in the case of a guitar string, for example.
So we have these distinctions, which we're gonna have to
keep track of for a minute, between traveling waves and
(08:48):
standing waves. And what I want to emphasize is how
important both types of waves are in music. You can't
have music without both of them. And the reason is
that what you do when you play the guitar, or
play a piano or play an organ is you're creating
a standing wave somewhere on the instrument. You're making a
(09:08):
wave in a part of the instrument that doesn't have
to move anywhere. It's staying on the instrument. The instrument
is not moving. There's a piece of it that's vibrating
back and forth, but it's vibrating in place.
Speaker 1 (09:17):
So the guitar string has a standing wave on it exactly.
Speaker 2 (09:21):
But that standing wave then creates traveling waves in the air,
and those sound waves then move outward a wave from
the instrument and eventually reach the ears of listeners. So
you need both of them. You need something to happen
on the instrument, and then you need that whatever it
is to create waves that can go somewhere and be heard.
(09:43):
And this brings up the most important distinction between these
two types of waves for the purposes of particle physics,
aside from the fact that one of them goes somewhere
the other doesn't, which is that traveling waves can vibrate
at any frequency you like, standing waves cannot. So what
do I mean by that, Well, when you pluck a
(10:05):
guitar string, assuming you're not putting your hands on it anywhere,
just you just take the guitar string as it is
and you pluck it. Where you take a violin and
string and you pluck it, or you take a string
on a piano and you hammer it, you will get
one tone and it's the same tone every time. And
so a musical instrument like a piano or like a
guitar piano is a better example because with guitars, we
(10:25):
put our hands on the instrument shortened the strings of
it gets complicated, and a piano, we just hit the strings.
We only get the notes we get. We can't get
notes in between, because each string gives you a particular note,
and so you know there are eighty eight notes on
a piano keyboard, and we have eighty eight sets of strings,
one for each.
Speaker 1 (10:44):
Note, and each one is a different length, etc. And
that's what gives them the different.
Speaker 2 (10:47):
Notes, different length and tension. But yes, each one has
a particular frequency associated with it, and the reason for
this is a phenomenon known as resonance. It's the same
reason that when we strike a pendulum or make a
pendulum swing back and forth, as in the old pendulum
clocks of previous generations, they vibrate with a predictable frequency.
(11:10):
And this predictability and this single mindedness, this resonance phenomenon,
is what allows us to make musical instruments of most types,
because most musical instruments, the human voice being an exception,
are not designed to make all possible notes. They're designed
to make some set of them. But fortunately this is
not true of traveling waves, which can have any frequency.
(11:33):
And if you think about it, that's essential in music.
Suppose that air and its waves could only carry specific frequencies, well,
then you'd have to match your instrument to the air
or the sound just wouldn't go anywhere. Whereas in fact,
musical instruments of any frequency, or if you sing a note,
(11:53):
no matter what note you see, it will always travel
through the air because traveling waves are free to go out,
they're flexible. So that's a key distinction that standing waves
have to do with resonance and traveling waves have to
do with non resonant phenomena and can have any frequency
they like. OK, this is as I said, It's key
(12:13):
for music, but it's also key for the.
Speaker 1 (12:15):
Universe connected to us. For the universe, how do this
concept of standing waves and traveling waves help us understand
what we're made out of and how everything works.
Speaker 2 (12:24):
There's certain things about light and light waves, which are
essential features of all the waves of the universe, but
there's also a thing they don't have. Light waves are
always traveling waves, or precisely, lightwaves in empty space are
always traveling waves. You can do things in materials to
make them do other things, but that's not really critical.
(12:47):
I'm trying to focus our attention on what happens in
empty space, and lightwaves can cross empty space just fine,
no matter what their frequency. Radio waves, microwaves, gamma rays,
X rays, and visible light. They all cross the universe
at the speed of light, and they have no problem
with that, and they can have any frequency you like,
all the colors that we can see, and then all
the other frequencies that our eyes cannot detect, but our
(13:10):
scientific instruments can. So light waves are of a certain sort,
and there are a couple of other types of waves
that are part of the cosmos. Gravitational waves are another
example that have this property. They're only traveling lives. But
the waves that we are made from that ultimately we
call electrons or the quarks out of which protons and
(13:31):
neutrons are made. These waves can both travel and stand,
and that's connected with the fact that the particles that
we call electrons can move and they can also stop,
whereas the particles that are associated with light, which we
call photons, they cannot stop in empty space. They always
(13:54):
are traveling.
Speaker 1 (13:54):
So we talk about this on the podcast sometimes and
we say that particles can have energy of motion, the
kinetic energy they're moving through the universe, but they can
also have energy in their mass. Right so electron just
sitting there has energy inside of it. It's equals mc squared,
but that photons only have energy of motion.
Speaker 2 (14:11):
For example, right now, we have to be careful about
language again because the word mass is also ambiguous. We
are specifically talking about what scientists referred to as rest mass,
which is the mass that's intrinsic to an object. You
will also hear people say that mass increases with speed.
They are talking about a different type.
Speaker 1 (14:31):
Of mass, right, And we had a whole podcast episode
about relativistic mass and why it's actually just to stand
in for energy, and so people should go dig into
that if they're curious. But here we're talking about mass
as being the energy of an object at rest.
Speaker 2 (14:43):
That's right, And so photons don't have any and effectively
that's why they can never stop. But electrons and quarks
and most of the different types of particles that we
know about so far in the universe, most of them
do indeed have the ability to be at re and
they have a certain amount of energy even when they're
at rest, and that energy, via equals mc squared, translates
(15:06):
into what we call their mass, which is the difficulty
for anyone to make them go from at rest to
moving at a certain speed. It's a form of stubbornness.
If a rock has mass, it's the statement that you're
going to have to make an effort if you want
to throw it across the room.
Speaker 1 (15:24):
I hear you trying to avoid using the word inertia.
You're explaining all the same concepts where you're not using
that word.
Speaker 2 (15:29):
Why is that, Well, inertia has, like most words in English,
has a couple of different meanings. Right, Inertia is certainly
a notion of the difficulty of making something stop in English, Right,
if something has inertia, you mean that I'm not going
to be able to change its direction or slow it
down very much. It's going to continue doing what it's
doing via inertia. But what scientists mean by inertia is
(15:50):
subtly different from that. It's not exactly the same. So
it's another word which requires a discussion. And the unnecessary
discussions are ones that I don't I don't avoid because
they're not worth having. But we only have so much time,
and there's only so many pages in a book. We
have to pick our battles carefully, so I decided not
to pick that one.
Speaker 1 (16:10):
All right. I have a bunch more questions for Matt
about how the universe works and how we can really
understand the Higgs field correctly. But first, let's take a
quick break. Okay, we're back and we're talking to Professor
(16:34):
Matt Stressler, author of the new book Waves in an
Impossible See, who wants us to really understand how the
universe is all made of waves and how that's crucial
to understanding how particle physics and the Higgs Boson works.
All right, so now you've described the universe to us
in terms of waves, and you're saying that particles that
have mass are little standing waves, and particles in motion
(16:57):
are traveling waves. And this is kind of re utionary
way to think about the universe, but it's also something
we hear about sometimes, like particles are ripples and quantum fields,
they're not actually little dots of stuff. And so I
went out there and I asked our listeners to give
us their sort of mental image of these things, because
I wanted us to be able to calibrate this conversation,
and also I was curious your reaction to some of
(17:19):
these thoughts. So I asked our listeners to give us
their mental picture of an electron, and then I also
asked them to give us their mental picture of a
ripple in a quantum field, which was a little bit
of a trick question because you know, we think of
an electron as a ripple in a quantum field. I
was curious if listeners had the same mental picture for
these two or not. So here's what listeners had to
(17:41):
say for the mental picture of an electron, and those
of you out there listening, pause for a moment and think,
what is your mental picture of an electron.
Speaker 3 (17:49):
My mental image of an electron is probably still from
back in my Navy days when I learned electronics, a
group of a small little marbles surrounded by a one
or more spinning marbles in an orbit around the center,
looking more like a nuclear power plant logo or something.
Speaker 4 (18:12):
I see an electron as kind of like a ripple,
almost like in space itself, in a certain way that
you can squeeze closer together in anyone direction, so you
can look at it closer and closer in anyone direction,
but as you squeeze it, it gets bigger in the
other directions, keeping you from like localizing it. I used
(18:32):
to think of it as a particle, but that didn't
super make sense to me, because you can always localize
it down smaller, so it would have no volume. So
I think of it as a ripple in something though
I'm not really sure what.
Speaker 5 (18:44):
Well, I don't know, like a little fuzzy blob that's
right where I see it, except it's not where I
see it, because something about observing something changes it. But
it's not really there anymore.
Speaker 1 (18:59):
And here's what people say when I asked them what
they thought about a quantum field ripple.
Speaker 3 (19:04):
I would have to say the best way to describe
for me is like looking at a piece of lasagna
with ripples in at lengthwise. That's the only thing I
can think of, like a.
Speaker 1 (19:13):
Wave in a pond, but without the vertical more of
a horizontal side side.
Speaker 4 (19:19):
In a lot of ways, it's the same thing as
a particle to me. It's really just a wave that's
sort of localized in one space.
Speaker 2 (19:26):
When I think about a quantum field, I see the
image of a three dimension of great space moving.
Speaker 6 (19:33):
Like a wave.
Speaker 5 (19:34):
It's like the geometry of existence shifts. It doesn't look
like it normally does, and you can almost see through
to the other side of it.
Speaker 7 (19:46):
Pretty much. I think as you would have a ripple
in a pond if you threw a stone in so
concentric series of waves heading away but getting less in magnitude,
but trying to imagine that is going out in three
dimensions as opposed to two.
Speaker 8 (20:03):
Well, actually it's a black space surrounded by a water
like wave small one.
Speaker 9 (20:16):
That is, so if you imagine an infinite plane and
then someone takes I don't know around, you know, lollipopper sucker,
and this plane is somehow elastic, are made of rubber,
and you push up on that plane, except that it
(20:38):
only wants to deform locally. It doesn't stretch out evenly
across the width of the plane. I sort of envision
it as a large plane with like a sort of
three D parabolic shape pushed up into it.
Speaker 6 (20:55):
I guess I kind of picture a sheet that you've
been pulled taut and then shake it like a salt shaker.
Speaker 10 (21:08):
I picture a quantum field being kind of like a
transparent sphere, and then a ripple in it would be
like a little light bulb or something in the middle
flicking on.
Speaker 1 (21:20):
So quite a variety of answers here, Matt, What do
you think about these mental pictures of electrons versus quantum fields.
Do any of these aligned with the way you think
about it?
Speaker 6 (21:29):
Well?
Speaker 2 (21:30):
I love this range of answers because I think it
points out a range of fascinating challenges that both non
scientists have and trying to understand what physicists are saying,
and physicists have and journalists are trying to convey the
stuff have in trying to come up with a language
that is clear enough, and of course some of the
(21:53):
things we've been talking about, the difficulty of understanding the
word wave as scientists use it and don't use it
is one of the difficulties because if your image of
an electron is as a single crest in water, well
that may or may not work very well. For example,
if your image of a photon, a particle of light
(22:16):
is as a single crest. If your mental image somehow
takes a light wave that consists of many crests and
it divides it into its individual crests, well then it's
confusing because why would a photon if it's just a
single crest have a frequency or a wavelength. Wavelength has
to do with how far apart the crests are. You
(22:36):
end up in puzzles that you can't pull yourself out of.
And then we have the problem of the word particle.
We haven't talked about it yet. So let's spend a
moment on that. In English, we have all sorts of
things that we would refer to as a particle, a dust, particle,
it's a tiny little thing that it looks a little
bit like a ball or something, you know, ball like
(22:57):
but small, A particle of sand, it's a grain, it's
a little thing. You could put it in your hand,
it'll just sit there. And that is a concept of
particle which is reinforced for those who do take physics
in freshman year, that's the way it's talked about. For
those who even go on to junior year quantum physics,
(23:17):
that's still kind of the way it's talked about. Even
though there's some wavelike things that come in when we
talk about particle, we still sort of envision this thing
with a position. And if you've read about quantum physics
just as a layperson, and you read what Neils Bore,
the great quantum physics pioneer, had to say about the electrons,
(23:39):
he said, sometimes they're like particles, sometimes they're like waves.
And what did he mean. He meant that it's an
object with a position. But come nineteen forties, nineteen fifties,
slowly but surely, the math stopped talking about electrons that way.
And the weird thing is that the language of physicists
(24:00):
it's took much longer to change, and even the way
I was taught, because first I learned junior quantum physics,
in which we think of particles as things with positions
and moving around. Maybe you can't specify how they move
around as well as you did, but a particle is
an object with a position that moves around on some path.
(24:23):
That is not what we mean when we talk about
elementary particles, not since the nineteen fifties or so, and
instead we mean something much stranger and much less familiar.
And so I'll come back to that, but you need
to step away from the notion of particle that's in
(24:43):
your head, and a notion which is hard to step
away from because, as a number of listeners sort of
referred to, there is this cartoon of an atom, which
is a part of our culture. It consists of a
blob at the center made of neutrons and protons, with
these electrons going around in orbits outside, and the electron
is drawn as a dot usually blue. Okay, it's not blue,
(25:08):
but it's also not a ball or a dot. That's
not the right way to think about it, and this
is critically important if you want to understand why an
electron has mass. Why does an electron that is at
rest have any energy if it's just the dot, why
would there be any in there? Where would it come from?
You know, that's a fundamental puzzle, and understanding that electrons
are waves in the nineteen fifties language of what is
(25:32):
the math of what is known as quantum field theory
is where we get our modern notion of what electrons
are and what their mass consists of. And in that picture,
electrons are not to be thought of as dots going
around on paths. Now, quantum physics of the nineteen twenties
already taught us that, but even the word particle as
(25:55):
we use it in quantum field theory should not be
thought of in that way. So let's now take a
step back with that rather cryptic remark and look at
what the language of quantum field theory really tells us
about electrons and photons, because we should kind of do
them in parallel. Remembering there's this difference that electrons can
(26:17):
be standing waves or traveling waves, but photons are easier
to think about because we know something about them in life,
and our eyes absorb them. Let's kind of do them
a little bit in parallel. So the real surprise about
light is that it doesn't behave like we'd expect waves
(26:38):
to behave. And yet another way, and one way to
talk about that is to talk about sound. We have
this naive notion which makes perfect sense that if you
speak at a certain volume, you could speak at half
that volume and then the sound would be quieter, or
you could speak at half of that volume and then
be even quieter, and half of that and be even quieter,
and you could keep going, you know, sort of a
(27:00):
you know's paradox kind of thing. Divide in half and
then divide in half and find and you can just
speak in a quieter and quieter voice as far down
as you like. And you could have the same idea
about a beam of light like a laser, like a
laser pointer, that you could, you know, sort of turn
it down so it's half as bright, and turn it
down so it's half as bright again, and half is
bright again every time, we just get a dimmer beam,
and you could go down as far as you like
to infinity. It's not true, and it's similar to the
(27:23):
idea that if you were a person who'd never seen
paper before, and you were given a gigantic stack of
paper six feet high, you might not initially realize that, oh,
this thing is actually made of a large number of
sheets of paper. It's so big you don't recognize it.
But of course if you took the thing apart, you
would realize, oh, this stack of paper is made from
(27:44):
a huge number of individual sheets. In a similar non
obvious way, a light wave and again that's a series
of crests and troughs corresponding to a laser beam, can
be pulled apart into individual lit miniature waves and again
wave meaning a series of crests and troughs stacked together
(28:07):
to make something bright, but made from a huge number
of things that are extremely dim. And so you can't
take your bright thing and make it half as bright
and half as bright and half as bright again, any
more than you could take your stack of paper and
divide it in half, and divide it in half, and divide
and half forever, you would eventually reach individual sheets, and
you couldn't go any further. Well, that's the way it
is with laser light. It's not obvious, but you can
break laser light up in half and again and again,
(28:28):
and you will eventually find yourself with something indivisible in
individual indivisible flashes of light, which we call photons. And
it was Einstein who proposed this without really fully understanding
yet how it would work. But he's responsible for this
idea too. So that's our first image of what photons are.
(28:51):
But remember, particle physicists call them particles. But you see,
they're not dots. They're like laser beams, only much dimmer.
Speaker 1 (29:01):
Right, They're flashes. They're not dots.
Speaker 2 (29:03):
They are particulate in the sense of indivisible, but they
are not particle like in the sense of dust boats
or sand grains. They don't have that shape. That's really
critically important. And what I've just told you about photons
is also true of electrons. They are not dots. They
(29:26):
are waves of minimal height, minimal brightness, you could say.
All of course, we understand the word brightness for light.
The word we use is intensity. In the scientific context,
we would say light has a certain intensity and there's
a minimum intensity that it can have, and electrons, in
a sense, are waves in something with a minimum intensity.
(29:47):
And the question now, though, is all right, But the
light waves they're always traveling. With electrons, they could be
traveling or they could be standing what's the difference. And
as you make an electron slow down, which you could
do with a battery nothing special, you can ask yourself, well,
how is the electron changing shape? Does it still look
(30:09):
like a long series of crests and troughs. And the
slower it is, the more it looks like just one
or two crests and troughs. And by the time you
slowed it down, it really does look a lot like
the ripple on a guitar string, just one crest standing still.
It's still vibrating, though like a guitar string, it's going
(30:30):
up and down. In some sense, it's diving back and forth.
It's doing something that's i mean, exactly how you visualize
it is a bit of a matter of taste. But
what's for sure is it might be standing still, but
that doesn't mean it's not doing anything.
Speaker 1 (30:44):
It's a standing wave, it's a vibration.
Speaker 2 (30:47):
It's a standing wave. So standing waves don't go anywhere,
but they're still doing something. And that picture an electron,
rather than being a dot, is a vibrating thing is
critical to understanding what it is and how it works.
(31:08):
And in particular, unlike a dot, which if it's moving,
would have motion energy, but if it's stopped, doesn't seem
dive energy at all. A vibrating thing has energy even
when it's not going anywhere. Ah, that's where the E
comes from. That gives us the mass the mc squared,
it's the energy of the vibration, and that's generally true.
(31:31):
That's fundamentally how particle physics works. The particles that have
mass can be slowed to a stop, at which point
they are standing waves. But they are not standing and
doing nothing. They are standing and vibrating, and they have
a certain amount of energy associated with them. So that
is why the particles of nature have a variety of
(31:53):
specific masses. They're standing waves, and remember, traveling waves can
have any energy you like, but standing waves tend to
have a specific energy associated with the idea of resonance.
Speaker 1 (32:07):
So an electron is a little vibration of the electron field,
and when it's at rest, it's vibrating at the resinant
frequency of the electron field, and the muon fields has
its own resonant frequency, and the quark fields have their
own resonant frequency, and that's what gives all these particles
different masses.
Speaker 2 (32:24):
That's the bigger picture, right. So up to this point,
I've really only explained that the electron is a resonant,
vibrating thing, but I haven't told you what it's a
vibration of. And that does bring us back to the
question at the very beginning when I suggested that you know,
we're made of waves, but I avoided the question of
what we are waves in. Yeah, and I said, well,
(32:45):
maybe we're waves of the universe in some sense, and
scientists don't know what we are waves in in some
sort of deep sense, but we do know something. We
understand how these waves work. And the language that we
use is the language of fields, which are things that
(33:09):
are present everywhere in the universe, the most famous being
the electric field or the magnetic field, which scientists put
together into the electromagnetic field that you treat them as
a single unit. And waves in the electromagnetic field are
what we call light. And there are again these quote particles, namely,
(33:31):
the dimmest possible wave in the electromagnetic field is what
we call a photon, a quote particle of light. So
that gives us a conceptual package where Okay, there's something
called the electromagnetic field that's an aspect of the universe.
We don't really understand what it is, but we understand
how it works. We know that it has waves, and
(33:53):
those waves have the dimmest possible flash associated with them,
the dimmest possible wave, and those waves are what we
call particles. Although, as I emphasized the book, the word
particle is not a very good word, and there is
another word available, which once I reach that part of
the book, I only use that word afterwards, which is
the word wavecle And I like it because it emphasizes
(34:19):
this thing is really wavelike and not dust particle like.
But it also brings forth the notion that it's particulate.
It's somehow a bit of a wave, and yet it's
sufficiently unfamiliar as a term that it carries less cultural
and conceptual baggage. It leaves your brain fear to understand
(34:39):
what it might actually be. And so this little bit
of a wave is a good concept, I.
Speaker 1 (34:44):
Think, yeah, And I'll say that reading your book it
made it, at the same time easier to understand, because
you invented some of your own words for clarity. It
also made it more of a challenge because it was
sometimes harder to connect it to existing established ideas and
concepts that people might have in their heads. But I
think it's beautiful as a sort of like standalone structure,
(35:04):
Like I'm gonna start from nothing and build up a
bunch of concrete ideas and piece them together for you.
You follow along that road, it really does all come together.
All right, We're gonna get even deeper into this, but
first we're going to take a quick break. We're back
(35:31):
and I'm talking to Professor Matt Strassler, author of Waves
and an Impossible See. So bring it together for us now,
because we could talk for hours, but I want to
get our listeners to a place where they can understand
how this wavecle picture of the universe and wavecles as
like either standing waves or traveling waves or both, helps
us understand the Higgs boson and then why this new
(35:53):
understanding can be consistent with the principle of relativity.
Speaker 2 (35:57):
Okay, so let's summarize kind of where we've which is
a long way. We went from electrons being these blue
dots and now suddenly they are these standing vibrations. They
have energy associated with their vibration. And it's really important
to understand the electron is really the vibration. It's not
that an electron is vibrating. The electron is the vibration. Right.
(36:21):
There is this thing which is a part of the universe.
We don't understand it very well. We call it the
electron field. It's analogous to the electromagnetic field, whose ripples
are associated with photons. There is this thing we call
the electron field. We understand good math for it, we
don't understand what it is, but its vibrations are what
we call electrons, and those electrons have a particular frequency
(36:45):
when they are standing. There is a resonance associated with
the electron field that determines how fast a stationary electron vibrates,
and that in turn determines how much energy it has
and therefore determines how much mass it has. This connection
between resonant frequency, energy and mass, which comes out of
Einstein's core ideas, is what gives us a link between
(37:10):
resonance and mass. But now, what about this resonance, What
is resonating? Well, again, what's resonating is the thing that's vibrating,
the electron field itself. We don't understand what it is,
but we understand what it's doing. It is vibrating in
a resonant way, somewhat as a guitar string, when plucked,
will vibrate at a particular resonant frequency. So when you
(37:33):
take a guitar or piano and you play all its notes,
you get various frequencies. When you take the universe and
you make it vibrate in all the ways it likes
to vibrate, you get the particle masses. There's a direct
link between the frequencies at which the universe likes to
vibrate and the masses of the elementary particles. And now
that gives us a chance to guess what the Higgs
(37:54):
field is actually doing. The Higgs field is changing the
frequencies of the other field. It's like tuning a guitar.
It is able to change the electron field's resonant frequency,
and therefore it can change the mass of the electron. Now,
(38:16):
a guitar player would be able to change all the
frequencies independently, right if you could tune anyone's string independently
of all the others. The Higgs field can't do all that.
It just changes the frequencies of all of the elementary
particles together, starting from zero and moving them up to
where they are today.
Speaker 1 (38:33):
But they all get different values.
Speaker 2 (38:35):
They all get different values, and the key to why
they get different values is related to how strongly the
Higgs field interacts with a particular field. So, for example,
the electron field. The electron has a relatively small mass,
and that reflects the fact that the electron field interacts
relatively weakly with the Higgs field, and so when the
(38:56):
Higgs field does its thing, it doesn't change the electron
frequency that much. But the top quark, which is the
particle whose mass is largest among all the particles known
so far, that is a vibration of the top quark field.
We're really inventive with our names, right. Top quark is
a vibration of the top quark field. The top quark
(39:17):
field interacts very strongly with the Higgs field, and therefore
the top quark field has a high resonant frequency, and
therefore the top quark has a high mass.
Speaker 1 (39:29):
So the Higgs is changing how all these fields vibrate,
changing their resonant frequencies, which really changes the masses of
what we're calling particles or wavecles. There's no molasses or
snow involved at all.
Speaker 2 (39:42):
That's right. In fact, if you think about it, what
the Higgs field is doing is really not affecting particles directly, right.
It affects the other fields, changes their properties, and then
it's just a consequence of quantum physics that the waves
in those fields come in these unks that we call
quote particles or wavehicles. And then it's a consequence of
(40:05):
relativity that the energy of their vibration has something to
do with mass equals mc squared. The direct link between
the mass of the electron and the Higgs field doesn't
really exist. You have to go through these other pieces,
and that is why in order to explain how the
Higgs field works, I had to explain both quantum physics
(40:26):
to some degree and relativity to some degree in the
book before we could get to that. So, in a way,
the book was about trying to make sure some aspects
of relativity were clear, some aspects of waves were clear,
some aspects of quantum physics were clear, and then bringing
them all together so that we could understand what wavecles are.
(40:47):
And at that point explaining what the Higgs field does
is not so difficult. Just change the frequency of a field.
Changes the frequency of a field, then it changes the
way it vibrates, and that's going to change the mass
of the corresponding particle. That's all. You have to first
understand that electrons aren't like dust particles, and they don't
get their mass through any mechanism that particles could possibly have.
(41:10):
They have to be vibrating objects in order for that
to make any sense.
Speaker 1 (41:14):
And photons, you're saying, are just traveling waves, which means
there is no standing wave for a photon. Photons have
no resonant frequency because the Higgs doesn't interact with the
electromagnetic field.
Speaker 2 (41:26):
Yeah, to be more precise, the electromagnetic field has no
resonant frequency, and correspondingly, it has no standing waves in
empty space, and therefore photons don't have any rest mass.
And yes, one reason for this, let's say, is that
the Higgs field does not directly interact with the electromagnetic field.
But it's important that not only the Higgs field that
(41:46):
we know doesn't do that, but there aren't any other
Higgs like fields that get in the way either. Now,
why is this? Why is it that the electromagnetic field
has this property whereas the electron field doesn't. Why is
it that the electromagnetic field doesn't interact with the Higgs
field and its particles remain massless while the electron field does.
We don't know. We don't have an understanding of the
(42:10):
pattern of which fields the Higgs field interacts with, or
more precisely, we have partial understanding. We understand why Higgs
field of the sort that we have in our universe
can't interact with the electromagnetic field, but we don't know
why we had to have a Higgs field of that
(42:30):
particular sort as opposed to Higgs field of some other sort.
And we certainly don't know why the electron fields interaction
with the Higgs field is weak while the top quarnfield's
interaction with the Higgs field is strong. We don't understand
that pattern at all, and not that there haven't been
many attempts to understand it. I, as a theoretical physicist,
have tried a few times, many others have, and we
(42:51):
have lots of great ideas, but we have no idea
which one of these ideas, if any, is correct, And
we keep hoping that particle physics garments will give us
some clues, and up to now Unfortunately they have not, and.
Speaker 1 (43:04):
It's really crucial because if the photon had even a
tiny amount of mass, it wouldn't have this property that
it's only a traveling wave, which would mean that you
could catch up to it. You could see photons at rest.
You could have like a handful of photons, the way
you could have a handful of electrons, and you could
have them at various velocities, which would mean that observers
(43:24):
wouldn't have to see the speed of light always as
the speed of light. It would feel like a very
different universe.
Speaker 2 (43:29):
It certainly would feel very different because there would be
situations in which light and radio waves from a single
event would arrive at different times. There would be distortions
of things that you see. I mean, you can sort
of imagine if sound waves didn't all arrive at the
same time, if the speed of sound weren't basically a constant.
Just think what would happen to music. You play a
(43:50):
piano and then the low notes arrive late and later
than the I mean, it would make a mess I.
Speaker 1 (43:55):
Thing the cellists have to play ahead of the violinists.
Speaker 2 (43:58):
Speaking would be tough, right, would be a very different world,
and so it is an important feature of our world.
Not only that speeds of different frequencies of light would
be different, but there's another consequence which in a way
might be even more important depending on how much mass
photons would have, which is that the range of electric
and magnetic fields would not be as large. The connection
(44:22):
is not obvious, and the reason has to do with
the following that the way that the Higgs field changes
the resonant frequency of another field is it makes it stiffer.
It makes it more difficult for it to vibrate, but
even more generally, it makes it more difficult for it
to change to vary. And so when you have an
(44:43):
electrically charged object, it can make in our universe an
electric field that goes out into the stars. A planet
can have a magnetic field that goes way out beyond
where the planet is, and that's very important for us
because the magnetic field off the Earth deflects particles from
the Sun that are flung out during solar flares, and
it protects us from the damage that such particles would do.
(45:05):
But if the photon had a mass, or more precisely,
if the electromagnetic field had a resonant frequency, that in turn,
would mean that the electromagnetic field would have more difficulty
spreading out, and magnetic fields wouldn't spread as far, and
so you could end up with a situation where the
magnetic field of the Earth might not reach out beyond
(45:25):
the surface of the Earth, and then we would not
be protected from these solar storms. So you know, we'd
survive because evolution is that way, right, Evolution would find
a way to create life that could survive all of that. Right,
we wouldn't, but we are certainly dependent upon this particular
feature of the universe, and so you know that's one
(45:47):
of the many ways in which the details of particle
physics affect the universe on a macro scale.
Speaker 1 (45:53):
Well, I think my last question for you is to
try to interpret what this all means. You've painted a
picture of the universe as field with waves, and in
your book, near the end, you write the universe rings
everywhere in everything, which I thought was very poetic. But
it makes me wonder, why is this, like, Why is
it that the mathematics of waves, which are very simple
(46:14):
and beautiful, are everywhere. Why are waves all over our universe,
both fundamental and emergent at so many different scales? What
does that say about the universe, that waves are everywhere?
Speaker 2 (46:25):
Well, I think maybe that question has two parts to it.
The first is why are waves everywhere? Even in the
macroscopic universe? Why do we see ocean waves and seismic
waves and waves and rubber And if you look closely
as find waves in metal. If you strike a bell,
there's waves inside. The why is that? And that turns
out to be a consequence of a simple idea, which
(46:48):
is that if I have a substance which is fairly
uniform and spread out like a chunk of metal, then
it is very easy to cause waves to occur. Let's
take the example of just water. Maybe that's simplest. If
(47:08):
you take a huge bucket of water or a big
pond or something, why is it so easy to get
ripples in it? Well, it's because it's so easy to
do something to one little piece of the water. Put
your hand in the water in one place, but that
is then going to have an impact on the bits
of the water right around it, which in turn is
going to have an impact on the parts of the
(47:29):
water right around them. You do something locally to the water,
but then the water can bring that effect outward. Further
and further away from where you pressed on the water
or hit the water, whatever it is you did to it,
And that propagation of an initial effect through this uniform
(47:50):
material almost automatically leads to waves. The math of waves
drops out of the equations, no matter what their details.
Speaker 1 (47:58):
So as long as you have a material where information
doesn't propagate instantly, then you're going to get propagation of
information and those are waves.
Speaker 2 (48:06):
Yeah, and it needs to be a uniform material because
if it isn't uniform, if it's just an agglomeration of
lots of different things, then as things move out, they'll
move out of completely different speeds depending on exactly what
they run into. But when you have a single material
like water or air, the speed at which things propagate
is constant or mere constant, and so as things propagate out,
(48:29):
they do so in a nice uniform way, and that
allows you to get ripples, where you get waves which
are simple and remain simple as they travel. So that's true.
In any material that's uniform, you almost always can get
waves of a certain type. So that's why they're ubiquitous
(48:49):
around us in ordinary materials. Now, if you think the
universe is like a material, it's certainly a uniform leaving
aside places where there's actually stuck. But if you go
out into the deep space, you're surrounded by whatever space is.
It's the same in all directions. It's the same in
all places. And we know this because we can measure
(49:09):
what the laws of nature are by looking at stars
or looking at other things in space, and the stars
are the same basically all across the universe. We don't
see big differences, so we know the universe is remarkably uniform,
and so to the extent it's a uniform material like thing,
the fact that it has waves in it is no surprise.
But we don't know why it's a uniform thing, and
(49:35):
so at some level there's still plenty of why questions
that are out there for which we don't know answers.
That's kind of where we.
Speaker 1 (49:42):
Are, wonderful. Well, tell us again the title of your
book and where listeners can find it if they'd like
to understand even deeper all of these concepts.
Speaker 2 (49:51):
Well, the title I came up with, and I'm delighted
that the publisher accepted it is waves in an impossible see,
beautiful waves being us the stuff we're made from and
the impossible see being this space we live in that's
kind of like a material and kind of isn't. And
the book is available at any of your independent local
(50:11):
bookstores and of course at Amazon and Barnes and Noble
and all the other monsters that are happy out there
to show you the full range of books that are
available in the world. But yes, it's going to be
widely carried in bookstores and you should definitely check it out.
Speaker 1 (50:25):
Wonderful. Well, thanks again very much for coming on to
talk to us about all these incredible concepts and sharing
your particular view of the universe with all of us.
Speaker 11 (50:33):
Thank you so much, Dan, It's been really fun, all right,
interesting conversation there, sort of like a new way to
look at the world and to look at physics and
the nature of reality. Almost.
Speaker 2 (50:45):
Yeah.
Speaker 1 (50:45):
I hope that it gives listeners and readers of the
book a new way to think about these objects that
form the foundations of our whole world. That when you
take your body apart and imagine that it's made out
of atoms and protons and electrons, that you think about
those particles a little bit differently. Maybe you replace your
high school concept of an electron as a tiny little
blue ball with a little ripple in that electron field,
(51:07):
and have a better understanding for what's rippling there and
why the electron has mass, and how it's all connected
to the Higgs boson.
Speaker 11 (51:14):
Well, I was waving in and out of the interview
a little bit. So then the idea is that everything
is a wave. So it was wave, would you say
is a better word to describe what's going on at
the fundamental levels?
Speaker 1 (51:27):
Maths vision is that everything is a wave, a wave
in these things we call quantum fields that we don't
really understand. But if you dig into what it means
for a quantum field to do some waving, it can
give you a better understanding of what motion is, of
what mass is, of what energy is, and how the
Higgs boson gives those particles mass, not by filling the
(51:50):
universe with molasses that slows things down, but by changing
how those fields resonate, which really is what mass is
all about. So standing wave of resonance and a quantum field.
Speaker 9 (52:02):
Mmm.
Speaker 11 (52:02):
Interesting, Well, another cool idea out there, and it may
be a revolutionary way to look at the universe on
this journey to figure out how everything works.
Speaker 1 (52:12):
That's right. Matt Straussler is not just a super smart
theoretical physicist. He really does have a gift for accessible
explanations of deeply important concepts using intuitive ideas. Sometimes he
makes up his own words, like wavehicles because he wants
to avoid the baggage of words you've already heard. But
if you listen carefully and follow along, I really think
(52:33):
it can give you a deeper understanding of quantum fields.
Speaker 11 (52:36):
All right, well, check out his book Waves in an
Impossible Scene. We hope you enjoyed that.
Speaker 1 (52:41):
Thanks for joining us, See you next time. For more
science and curiosity, come find us on social media where
we answer questions and post videos. We're on Twitter, this
word instant and now TikTok. Thanks for listening and remember
that Daniel and Jorge Explain the Universe is a production
(53:03):
of iHeartRadio. More podcasts from iHeartRadio visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Hello everyone. Quick note that this episode is part two
of my conversation with theoretical physicist Matt Stressler about his
new book Waves in an Impossible Scene. If you haven't
yet heard part one, pause this episode and go back
listen to the first part. This stuff is hard enough
without listening to it backwards, so do the first things first.
(00:30):
Pause this episode and come right back. We'll wait for you. Hi.
I'm Daniel. I'm a particle physicist and a professor at
(00:53):
UC Irvine, and welcome to the podcast. Daniel and Jorge
explain the Universe, in which we dig deep into the
nature of space and time and particles, in which we
want you to understand our new ideas about how the
universe works and be bewildered with us about everything we
don't understand about the universe. Today we have an unusual episode,
(01:14):
and then it's part two. This is the second half
of my conversation with Professor Matt Stressler. In the first
part of the conversation, we reviewed relativity. How waves travel
through media, but light waves seem to travel through empty space.
How you can measure the speed of most waves like sound,
relative to their medium, but you can't measure the speed
(01:37):
of light relative to space, only to other things in space.
Matt is painting us a careful and insightful picture of
how everything is made out of waves, and why that's
crucial to understanding the last, the craziest, the most recent
wave to be discovered, waves in the Higgs field. So
(01:58):
here is part two of my conversation with Matt. Give
us a glimpse of how your mind works, how you
see the universe as being built out of waves, and
why you think this is so important for understanding the
Higgs field.
Speaker 2 (02:13):
I'll take you through that in a few steps, but
the most important to start with is we have to
deal with words. And this is a theme of the
book because I think it's a theme of human affairs
in general, and it's certainly a theme of scientific communication.
Speaker 1 (02:32):
Oh absolutely, And physics is terrible about words. I mean,
we use names for things totally inappropriately. Quarks have color
and flavor, Like, what are we talking about here? Why
don't we just invent new words to describe new things? Right?
Speaker 2 (02:45):
And we used to? I mean, you know, this is
in some sense of mid twentieth century development. But that said,
in order to think about things ourselves, we often borrowed
words from English, and particle is one of them. Wave
is another force, even theory. We have lots of words
that are part of physics dialect that we have taken
(03:08):
from English. And we humans, just in ordinary language, are
spectacularly good at using a single word with many definitions,
right we all know. You go to the dictionary and
you look up simple words and there's twelve definitions of
the same word. And yet in language we communicate with
each other switching definitions all the time. We may use
the same word in one sense in two different ways
(03:29):
and it doesn't bother us. Well, this is true of
physicists as well. We have our dialect, some words have
multiple meanings. We switch back and forth without a problem.
But of course, when you are switching dialects, when you
are trying to communicate physics to a non physics speaking
English speaker, just as when you try to switch from
French to English and you're trying to use words that
(03:52):
have multiple meanings without even thinking about it, you may
easily confuse your listener. And we do this all the time.
So they are famous phrases like an electron is part particle,
part way, it's a wave, part of the time, and
it's a particle part of the time. And aside from
the fact that that could mean many different things, and
(04:12):
over history it has meant at least two different things
to two different classes of people. It's really problematic that
the word particle has multiple meanings and the word wave
has multiple meanings, and the most common meanings in English
are not the ones that we are using here. So
we will not get anywhere if I don't spend a
minute on those definitions. So I'll start with wave. We'll
(04:35):
talk about waves for a while, because waves are such
a wonderful phenomenon. They underlie so many aspects. Obviously, I'm
the sound I'm using to communicate and the radio waves
that we're using to send all this information back and forth.
And also they're the fundamentals in music, just surrounded by
music in our modern world in the best and we're
senses and we should take a moment to think about
(04:56):
what we mean. And one thing we do not mean
is the thing that everybody means when they go to
the beach. Right, you go to the beach, Oh, that
is a great wave. I want to serf that one. Ooh,
here comes a big wave. Okay, what do we mean.
We mean, here comes a big crest in the water,
a big high point in the water, and it is
separated from the next high point by two low points,
(05:20):
and we call that crest a wave. That is not
what we are talking about here. We are not made
from single wave crests. No. Yet, the word wave as
used in science is a rich concept. There are waves
of many different shapes and sizes. For example, I'm speaking
now making sound waves, or if you're a recording engineer,
(05:42):
you will say I'm making a sound wave singular. So
a wave can be a very complicated shape. But to
keep things focused, let's talk about the simplest waves. And
the simplest waves are the ones that you make when
you sing. You sing a note, or you make a
pure tone on a musical instrument, and then you are
(06:03):
making a wave which consists of a whole bunch of
high points and a whole bunch of low points, a
whole bunch of crests and troughs equally spaced, and it
may be a long series of them.
Speaker 1 (06:14):
So imagine like a sine wave extending all the way
from negave infinity to positive infinity along the x axis
or something.
Speaker 2 (06:20):
If you like your tenth grade, eleventh grade math, Yes exactly,
or if you don't, it's just the ripples that you
would make in a pond. If you put your hand
in the water and moved it up and down regularly,
you would get a set of ripples. It would move outward.
That's a wave in science rather than a set of waves.
So it's more what a beach gore would call a
wave set or a wave train. And now even that
(06:43):
has a subtlety which I'll come back to you. But
of the types of waves that we encounter which scientists
talk about, there are two types, both of which are
really important and which have slightly different properties. And the
first one is the one that you would talk about
when you're talking about sound waves most of the time
from my voice to your ears. Those are traveling waves,
(07:04):
traveling meaning, as you would guess, they're moving in a
certain direction at a certain speed. And traveling waves include sound,
they include ocean waves, they include the seismic waves which
across the earth. They include light waves which cross the universe,
and they include the things we call particles and when
they're moving around. And the other type of wave that
(07:25):
we encounter is standing waves and standing waves have crests
and troughs that don't go anywhere. They just sort of
vibrate in place. So a classic example would be the
way in which a guitar string or a violin string
vibrates pluck it. It goes up and down and up
and down and up and down. There's a crest where
(07:47):
it bends upward, and then a moment later it's a
trough where it bends downward, and it goes up and
down and up and down and up and down. Or
maybe the air vibrating in an organ pipe. When you
make the organ pipe sound, what you're doing is you're
making the air inside ripple back and forth where it's
more dense in one place and then less dense, and
(08:07):
it goes back and forth and back and forth in
a regular repeating fashion. But it's not actually moving outside
the organ pipe. It's staying in the organ. OK. So
we have these two different types of waves, traveling waves
which move around, standing waves which they put and in
the case of traveling waves, as I described, it's not
a single wave crest, it's a whole set of them.
(08:28):
With standing waves, it can be any number of crests,
including just one. So it's still not a wave at
the beach because the wave of the beach is moving.
But it can be as simple as a wave at
the beach in the case of a guitar string, for example.
So we have these distinctions, which we're gonna have to
keep track of for a minute, between traveling waves and
(08:48):
standing waves. And what I want to emphasize is how
important both types of waves are in music. You can't
have music without both of them. And the reason is
that what you do when you play the guitar, or
play a piano or play an organ is you're creating
a standing wave somewhere on the instrument. You're making a
(09:08):
wave in a part of the instrument that doesn't have
to move anywhere. It's staying on the instrument. The instrument
is not moving. There's a piece of it that's vibrating
back and forth, but it's vibrating in place.
Speaker 1 (09:17):
So the guitar string has a standing wave on it exactly.
Speaker 2 (09:21):
But that standing wave then creates traveling waves in the air,
and those sound waves then move outward a wave from
the instrument and eventually reach the ears of listeners. So
you need both of them. You need something to happen
on the instrument, and then you need that whatever it
is to create waves that can go somewhere and be heard.
(09:43):
And this brings up the most important distinction between these
two types of waves for the purposes of particle physics,
aside from the fact that one of them goes somewhere
the other doesn't, which is that traveling waves can vibrate
at any frequency you like, standing waves cannot. So what
do I mean by that, Well, when you pluck a
(10:05):
guitar string, assuming you're not putting your hands on it anywhere,
just you just take the guitar string as it is
and you pluck it. Where you take a violin and
string and you pluck it, or you take a string
on a piano and you hammer it, you will get
one tone and it's the same tone every time. And
so a musical instrument like a piano or like a
guitar piano is a better example because with guitars, we
(10:25):
put our hands on the instrument shortened the strings of
it gets complicated, and a piano, we just hit the strings.
We only get the notes we get. We can't get
notes in between, because each string gives you a particular note,
and so you know there are eighty eight notes on
a piano keyboard, and we have eighty eight sets of strings,
one for each.
Speaker 1 (10:44):
Note, and each one is a different length, etc. And
that's what gives them the different.
Speaker 2 (10:47):
Notes, different length and tension. But yes, each one has
a particular frequency associated with it, and the reason for
this is a phenomenon known as resonance. It's the same
reason that when we strike a pendulum or make a
pendulum swing back and forth, as in the old pendulum
clocks of previous generations, they vibrate with a predictable frequency.
(11:10):
And this predictability and this single mindedness, this resonance phenomenon,
is what allows us to make musical instruments of most types,
because most musical instruments, the human voice being an exception,
are not designed to make all possible notes. They're designed
to make some set of them. But fortunately this is
not true of traveling waves, which can have any frequency.
(11:33):
And if you think about it, that's essential in music.
Suppose that air and its waves could only carry specific frequencies, well,
then you'd have to match your instrument to the air
or the sound just wouldn't go anywhere. Whereas in fact,
musical instruments of any frequency, or if you sing a note,
(11:53):
no matter what note you see, it will always travel
through the air because traveling waves are free to go out,
they're flexible. So that's a key distinction that standing waves
have to do with resonance and traveling waves have to
do with non resonant phenomena and can have any frequency
they like. OK, this is as I said, It's key
(12:13):
for music, but it's also key for the.
Speaker 1 (12:15):
Universe connected to us. For the universe, how do this
concept of standing waves and traveling waves help us understand
what we're made out of and how everything works.
Speaker 2 (12:24):
There's certain things about light and light waves, which are
essential features of all the waves of the universe, but
there's also a thing they don't have. Light waves are
always traveling waves, or precisely, lightwaves in empty space are
always traveling waves. You can do things in materials to
make them do other things, but that's not really critical.
(12:47):
I'm trying to focus our attention on what happens in
empty space, and lightwaves can cross empty space just fine,
no matter what their frequency. Radio waves, microwaves, gamma rays,
X rays, and visible light. They all cross the universe
at the speed of light, and they have no problem
with that, and they can have any frequency you like,
all the colors that we can see, and then all
the other frequencies that our eyes cannot detect, but our
(13:10):
scientific instruments can. So light waves are of a certain sort,
and there are a couple of other types of waves
that are part of the cosmos. Gravitational waves are another
example that have this property. They're only traveling lives. But
the waves that we are made from that ultimately we
call electrons or the quarks out of which protons and
(13:31):
neutrons are made. These waves can both travel and stand,
and that's connected with the fact that the particles that
we call electrons can move and they can also stop,
whereas the particles that are associated with light, which we
call photons, they cannot stop in empty space. They always
(13:54):
are traveling.
Speaker 1 (13:54):
So we talk about this on the podcast sometimes and
we say that particles can have energy of motion, the
kinetic energy they're moving through the universe, but they can
also have energy in their mass. Right so electron just
sitting there has energy inside of it. It's equals mc squared,
but that photons only have energy of motion.
Speaker 2 (14:11):
For example, right now, we have to be careful about
language again because the word mass is also ambiguous. We
are specifically talking about what scientists referred to as rest mass,
which is the mass that's intrinsic to an object. You
will also hear people say that mass increases with speed.
They are talking about a different type.
Speaker 1 (14:31):
Of mass, right, And we had a whole podcast episode
about relativistic mass and why it's actually just to stand
in for energy, and so people should go dig into
that if they're curious. But here we're talking about mass
as being the energy of an object at rest.
Speaker 2 (14:43):
That's right, And so photons don't have any and effectively
that's why they can never stop. But electrons and quarks
and most of the different types of particles that we
know about so far in the universe, most of them
do indeed have the ability to be at re and
they have a certain amount of energy even when they're
at rest, and that energy, via equals mc squared, translates
(15:06):
into what we call their mass, which is the difficulty
for anyone to make them go from at rest to
moving at a certain speed. It's a form of stubbornness.
If a rock has mass, it's the statement that you're
going to have to make an effort if you want
to throw it across the room.
Speaker 1 (15:24):
I hear you trying to avoid using the word inertia.
You're explaining all the same concepts where you're not using
that word.
Speaker 2 (15:29):
Why is that, Well, inertia has, like most words in English,
has a couple of different meanings. Right, Inertia is certainly
a notion of the difficulty of making something stop in English, Right,
if something has inertia, you mean that I'm not going
to be able to change its direction or slow it
down very much. It's going to continue doing what it's
doing via inertia. But what scientists mean by inertia is
(15:50):
subtly different from that. It's not exactly the same. So
it's another word which requires a discussion. And the unnecessary
discussions are ones that I don't I don't avoid because
they're not worth having. But we only have so much time,
and there's only so many pages in a book. We
have to pick our battles carefully, so I decided not
to pick that one.
Speaker 1 (16:10):
All right. I have a bunch more questions for Matt
about how the universe works and how we can really
understand the Higgs field correctly. But first, let's take a
quick break. Okay, we're back and we're talking to Professor
(16:34):
Matt Stressler, author of the new book Waves in an
Impossible See, who wants us to really understand how the
universe is all made of waves and how that's crucial
to understanding how particle physics and the Higgs Boson works.
All right, so now you've described the universe to us
in terms of waves, and you're saying that particles that
have mass are little standing waves, and particles in motion
(16:57):
are traveling waves. And this is kind of re utionary
way to think about the universe, but it's also something
we hear about sometimes, like particles are ripples and quantum fields,
they're not actually little dots of stuff. And so I
went out there and I asked our listeners to give
us their sort of mental image of these things, because
I wanted us to be able to calibrate this conversation,
and also I was curious your reaction to some of
(17:19):
these thoughts. So I asked our listeners to give us
their mental picture of an electron, and then I also
asked them to give us their mental picture of a
ripple in a quantum field, which was a little bit
of a trick question because you know, we think of
an electron as a ripple in a quantum field. I
was curious if listeners had the same mental picture for
these two or not. So here's what listeners had to
(17:41):
say for the mental picture of an electron, and those
of you out there listening, pause for a moment and think,
what is your mental picture of an electron.
Speaker 3 (17:49):
My mental image of an electron is probably still from
back in my Navy days when I learned electronics, a
group of a small little marbles surrounded by a one
or more spinning marbles in an orbit around the center,
looking more like a nuclear power plant logo or something.
Speaker 4 (18:12):
I see an electron as kind of like a ripple,
almost like in space itself, in a certain way that
you can squeeze closer together in anyone direction, so you
can look at it closer and closer in anyone direction,
but as you squeeze it, it gets bigger in the
other directions, keeping you from like localizing it. I used
(18:32):
to think of it as a particle, but that didn't
super make sense to me, because you can always localize
it down smaller, so it would have no volume. So
I think of it as a ripple in something though
I'm not really sure what.
Speaker 5 (18:44):
Well, I don't know, like a little fuzzy blob that's
right where I see it, except it's not where I
see it, because something about observing something changes it. But
it's not really there anymore.
Speaker 1 (18:59):
And here's what people say when I asked them what
they thought about a quantum field ripple.
Speaker 3 (19:04):
I would have to say the best way to describe
for me is like looking at a piece of lasagna
with ripples in at lengthwise. That's the only thing I
can think of, like a.
Speaker 1 (19:13):
Wave in a pond, but without the vertical more of
a horizontal side side.
Speaker 4 (19:19):
In a lot of ways, it's the same thing as
a particle to me. It's really just a wave that's
sort of localized in one space.
Speaker 2 (19:26):
When I think about a quantum field, I see the
image of a three dimension of great space moving.
Speaker 6 (19:33):
Like a wave.
Speaker 5 (19:34):
It's like the geometry of existence shifts. It doesn't look
like it normally does, and you can almost see through
to the other side of it.
Speaker 7 (19:46):
Pretty much. I think as you would have a ripple
in a pond if you threw a stone in so
concentric series of waves heading away but getting less in magnitude,
but trying to imagine that is going out in three
dimensions as opposed to two.
Speaker 8 (20:03):
Well, actually it's a black space surrounded by a water
like wave small one.
Speaker 9 (20:16):
That is, so if you imagine an infinite plane and
then someone takes I don't know around, you know, lollipopper sucker,
and this plane is somehow elastic, are made of rubber,
and you push up on that plane, except that it
(20:38):
only wants to deform locally. It doesn't stretch out evenly
across the width of the plane. I sort of envision
it as a large plane with like a sort of
three D parabolic shape pushed up into it.
Speaker 6 (20:55):
I guess I kind of picture a sheet that you've
been pulled taut and then shake it like a salt shaker.
Speaker 10 (21:08):
I picture a quantum field being kind of like a
transparent sphere, and then a ripple in it would be
like a little light bulb or something in the middle
flicking on.
Speaker 1 (21:20):
So quite a variety of answers here, Matt, What do
you think about these mental pictures of electrons versus quantum fields.
Do any of these aligned with the way you think
about it?
Speaker 6 (21:29):
Well?
Speaker 2 (21:30):
I love this range of answers because I think it
points out a range of fascinating challenges that both non
scientists have and trying to understand what physicists are saying,
and physicists have and journalists are trying to convey the
stuff have in trying to come up with a language
that is clear enough, and of course some of the
(21:53):
things we've been talking about, the difficulty of understanding the
word wave as scientists use it and don't use it
is one of the difficulties because if your image of
an electron is as a single crest in water, well
that may or may not work very well. For example,
if your image of a photon, a particle of light
(22:16):
is as a single crest. If your mental image somehow
takes a light wave that consists of many crests and
it divides it into its individual crests, well then it's
confusing because why would a photon if it's just a
single crest have a frequency or a wavelength. Wavelength has
to do with how far apart the crests are. You
(22:36):
end up in puzzles that you can't pull yourself out of.
And then we have the problem of the word particle.
We haven't talked about it yet. So let's spend a
moment on that. In English, we have all sorts of
things that we would refer to as a particle, a dust, particle,
it's a tiny little thing that it looks a little
bit like a ball or something, you know, ball like
(22:57):
but small, A particle of sand, it's a grain, it's
a little thing. You could put it in your hand,
it'll just sit there. And that is a concept of
particle which is reinforced for those who do take physics
in freshman year, that's the way it's talked about. For
those who even go on to junior year quantum physics,
(23:17):
that's still kind of the way it's talked about. Even
though there's some wavelike things that come in when we
talk about particle, we still sort of envision this thing
with a position. And if you've read about quantum physics
just as a layperson, and you read what Neils Bore,
the great quantum physics pioneer, had to say about the electrons,
(23:39):
he said, sometimes they're like particles, sometimes they're like waves.
And what did he mean. He meant that it's an
object with a position. But come nineteen forties, nineteen fifties,
slowly but surely, the math stopped talking about electrons that way.
And the weird thing is that the language of physicists
(24:00):
it's took much longer to change, and even the way
I was taught, because first I learned junior quantum physics,
in which we think of particles as things with positions
and moving around. Maybe you can't specify how they move
around as well as you did, but a particle is
an object with a position that moves around on some path.
(24:23):
That is not what we mean when we talk about
elementary particles, not since the nineteen fifties or so, and
instead we mean something much stranger and much less familiar.
And so I'll come back to that, but you need
to step away from the notion of particle that's in
(24:43):
your head, and a notion which is hard to step
away from because, as a number of listeners sort of
referred to, there is this cartoon of an atom, which
is a part of our culture. It consists of a
blob at the center made of neutrons and protons, with
these electrons going around in orbits outside, and the electron
is drawn as a dot usually blue. Okay, it's not blue,
(25:08):
but it's also not a ball or a dot. That's
not the right way to think about it, and this
is critically important if you want to understand why an
electron has mass. Why does an electron that is at
rest have any energy if it's just the dot, why
would there be any in there? Where would it come from?
You know, that's a fundamental puzzle, and understanding that electrons
are waves in the nineteen fifties language of what is
(25:32):
the math of what is known as quantum field theory
is where we get our modern notion of what electrons
are and what their mass consists of. And in that picture,
electrons are not to be thought of as dots going
around on paths. Now, quantum physics of the nineteen twenties
already taught us that, but even the word particle as
(25:55):
we use it in quantum field theory should not be
thought of in that way. So let's now take a
step back with that rather cryptic remark and look at
what the language of quantum field theory really tells us
about electrons and photons, because we should kind of do
them in parallel. Remembering there's this difference that electrons can
(26:17):
be standing waves or traveling waves, but photons are easier
to think about because we know something about them in life,
and our eyes absorb them. Let's kind of do them
a little bit in parallel. So the real surprise about
light is that it doesn't behave like we'd expect waves
(26:38):
to behave. And yet another way, and one way to
talk about that is to talk about sound. We have
this naive notion which makes perfect sense that if you
speak at a certain volume, you could speak at half
that volume and then the sound would be quieter, or
you could speak at half of that volume and then
be even quieter, and half of that and be even quieter,
and you could keep going, you know, sort of a
(27:00):
you know's paradox kind of thing. Divide in half and
then divide in half and find and you can just
speak in a quieter and quieter voice as far down
as you like. And you could have the same idea
about a beam of light like a laser, like a
laser pointer, that you could, you know, sort of turn
it down so it's half as bright, and turn it
down so it's half as bright again, and half is
bright again every time, we just get a dimmer beam,
and you could go down as far as you like
to infinity. It's not true, and it's similar to the
(27:23):
idea that if you were a person who'd never seen
paper before, and you were given a gigantic stack of
paper six feet high, you might not initially realize that, oh,
this thing is actually made of a large number of
sheets of paper. It's so big you don't recognize it.
But of course if you took the thing apart, you
would realize, oh, this stack of paper is made from
(27:44):
a huge number of individual sheets. In a similar non
obvious way, a light wave and again that's a series
of crests and troughs corresponding to a laser beam, can
be pulled apart into individual lit miniature waves and again
wave meaning a series of crests and troughs stacked together
(28:07):
to make something bright, but made from a huge number
of things that are extremely dim. And so you can't
take your bright thing and make it half as bright
and half as bright and half as bright again, any
more than you could take your stack of paper and
divide it in half, and divide it in half, and divide
and half forever, you would eventually reach individual sheets, and
you couldn't go any further. Well, that's the way it
is with laser light. It's not obvious, but you can
break laser light up in half and again and again,
(28:28):
and you will eventually find yourself with something indivisible in
individual indivisible flashes of light, which we call photons. And
it was Einstein who proposed this without really fully understanding
yet how it would work. But he's responsible for this
idea too. So that's our first image of what photons are.
(28:51):
But remember, particle physicists call them particles. But you see,
they're not dots. They're like laser beams, only much dimmer.
Speaker 1 (29:01):
Right, They're flashes. They're not dots.
Speaker 2 (29:03):
They are particulate in the sense of indivisible, but they
are not particle like in the sense of dust boats
or sand grains. They don't have that shape. That's really
critically important. And what I've just told you about photons
is also true of electrons. They are not dots. They
(29:26):
are waves of minimal height, minimal brightness, you could say.
All of course, we understand the word brightness for light.
The word we use is intensity. In the scientific context,
we would say light has a certain intensity and there's
a minimum intensity that it can have, and electrons, in
a sense, are waves in something with a minimum intensity.
(29:47):
And the question now, though, is all right, But the
light waves they're always traveling. With electrons, they could be
traveling or they could be standing what's the difference. And
as you make an electron slow down, which you could
do with a battery nothing special, you can ask yourself, well,
how is the electron changing shape? Does it still look
(30:09):
like a long series of crests and troughs. And the
slower it is, the more it looks like just one
or two crests and troughs. And by the time you
slowed it down, it really does look a lot like
the ripple on a guitar string, just one crest standing still.
It's still vibrating, though like a guitar string, it's going
(30:30):
up and down. In some sense, it's diving back and forth.
It's doing something that's i mean, exactly how you visualize
it is a bit of a matter of taste. But
what's for sure is it might be standing still, but
that doesn't mean it's not doing anything.
Speaker 1 (30:44):
It's a standing wave, it's a vibration.
Speaker 2 (30:47):
It's a standing wave. So standing waves don't go anywhere,
but they're still doing something. And that picture an electron,
rather than being a dot, is a vibrating thing is
critical to understanding what it is and how it works.
(31:08):
And in particular, unlike a dot, which if it's moving,
would have motion energy, but if it's stopped, doesn't seem
dive energy at all. A vibrating thing has energy even
when it's not going anywhere. Ah, that's where the E
comes from. That gives us the mass the mc squared,
it's the energy of the vibration, and that's generally true.
(31:31):
That's fundamentally how particle physics works. The particles that have
mass can be slowed to a stop, at which point
they are standing waves. But they are not standing and
doing nothing. They are standing and vibrating, and they have
a certain amount of energy associated with them. So that
is why the particles of nature have a variety of
(31:53):
specific masses. They're standing waves, and remember, traveling waves can
have any energy you like, but standing waves tend to
have a specific energy associated with the idea of resonance.
Speaker 1 (32:07):
So an electron is a little vibration of the electron field,
and when it's at rest, it's vibrating at the resinant
frequency of the electron field, and the muon fields has
its own resonant frequency, and the quark fields have their
own resonant frequency, and that's what gives all these particles
different masses.
Speaker 2 (32:24):
That's the bigger picture, right. So up to this point,
I've really only explained that the electron is a resonant,
vibrating thing, but I haven't told you what it's a
vibration of. And that does bring us back to the
question at the very beginning when I suggested that you know,
we're made of waves, but I avoided the question of
what we are waves in. Yeah, and I said, well,
(32:45):
maybe we're waves of the universe in some sense, and
scientists don't know what we are waves in in some
sort of deep sense, but we do know something. We
understand how these waves work. And the language that we
use is the language of fields, which are things that
(33:09):
are present everywhere in the universe, the most famous being
the electric field or the magnetic field, which scientists put
together into the electromagnetic field that you treat them as
a single unit. And waves in the electromagnetic field are
what we call light. And there are again these quote particles, namely,
(33:31):
the dimmest possible wave in the electromagnetic field is what
we call a photon, a quote particle of light. So
that gives us a conceptual package where Okay, there's something
called the electromagnetic field that's an aspect of the universe.
We don't really understand what it is, but we understand
how it works. We know that it has waves, and
(33:53):
those waves have the dimmest possible flash associated with them,
the dimmest possible wave, and those waves are what we
call particles. Although, as I emphasized the book, the word
particle is not a very good word, and there is
another word available, which once I reach that part of
the book, I only use that word afterwards, which is
the word wavecle And I like it because it emphasizes
(34:19):
this thing is really wavelike and not dust particle like.
But it also brings forth the notion that it's particulate.
It's somehow a bit of a wave, and yet it's
sufficiently unfamiliar as a term that it carries less cultural
and conceptual baggage. It leaves your brain fear to understand
(34:39):
what it might actually be. And so this little bit
of a wave is a good concept, I.
Speaker 1 (34:44):
Think, yeah, And I'll say that reading your book it
made it, at the same time easier to understand, because
you invented some of your own words for clarity. It
also made it more of a challenge because it was
sometimes harder to connect it to existing established ideas and
concepts that people might have in their heads. But I
think it's beautiful as a sort of like standalone structure,
(35:04):
Like I'm gonna start from nothing and build up a
bunch of concrete ideas and piece them together for you.
You follow along that road, it really does all come together.
All right, We're gonna get even deeper into this, but
first we're going to take a quick break. We're back
(35:31):
and I'm talking to Professor Matt Strassler, author of Waves
and an Impossible See. So bring it together for us now,
because we could talk for hours, but I want to
get our listeners to a place where they can understand
how this wavecle picture of the universe and wavecles as
like either standing waves or traveling waves or both, helps
us understand the Higgs boson and then why this new
(35:53):
understanding can be consistent with the principle of relativity.
Speaker 2 (35:57):
Okay, so let's summarize kind of where we've which is
a long way. We went from electrons being these blue
dots and now suddenly they are these standing vibrations. They
have energy associated with their vibration. And it's really important
to understand the electron is really the vibration. It's not
that an electron is vibrating. The electron is the vibration. Right.
(36:21):
There is this thing which is a part of the universe.
We don't understand it very well. We call it the
electron field. It's analogous to the electromagnetic field, whose ripples
are associated with photons. There is this thing we call
the electron field. We understand good math for it, we
don't understand what it is, but its vibrations are what
we call electrons, and those electrons have a particular frequency
(36:45):
when they are standing. There is a resonance associated with
the electron field that determines how fast a stationary electron vibrates,
and that in turn determines how much energy it has
and therefore determines how much mass it has. This connection
between resonant frequency, energy and mass, which comes out of
Einstein's core ideas, is what gives us a link between
(37:10):
resonance and mass. But now, what about this resonance, What
is resonating? Well, again, what's resonating is the thing that's vibrating,
the electron field itself. We don't understand what it is,
but we understand what it's doing. It is vibrating in
a resonant way, somewhat as a guitar string, when plucked,
will vibrate at a particular resonant frequency. So when you
(37:33):
take a guitar or piano and you play all its notes,
you get various frequencies. When you take the universe and
you make it vibrate in all the ways it likes
to vibrate, you get the particle masses. There's a direct
link between the frequencies at which the universe likes to
vibrate and the masses of the elementary particles. And now
that gives us a chance to guess what the Higgs
(37:54):
field is actually doing. The Higgs field is changing the
frequencies of the other field. It's like tuning a guitar.
It is able to change the electron field's resonant frequency,
and therefore it can change the mass of the electron. Now,
(38:16):
a guitar player would be able to change all the
frequencies independently, right if you could tune anyone's string independently
of all the others. The Higgs field can't do all that.
It just changes the frequencies of all of the elementary
particles together, starting from zero and moving them up to
where they are today.
Speaker 1 (38:33):
But they all get different values.
Speaker 2 (38:35):
They all get different values, and the key to why
they get different values is related to how strongly the
Higgs field interacts with a particular field. So, for example,
the electron field. The electron has a relatively small mass,
and that reflects the fact that the electron field interacts
relatively weakly with the Higgs field, and so when the
(38:56):
Higgs field does its thing, it doesn't change the electron
frequency that much. But the top quark, which is the
particle whose mass is largest among all the particles known
so far, that is a vibration of the top quark field.
We're really inventive with our names, right. Top quark is
a vibration of the top quark field. The top quark
(39:17):
field interacts very strongly with the Higgs field, and therefore
the top quark field has a high resonant frequency, and
therefore the top quark has a high mass.
Speaker 1 (39:29):
So the Higgs is changing how all these fields vibrate,
changing their resonant frequencies, which really changes the masses of
what we're calling particles or wavecles. There's no molasses or
snow involved at all.
Speaker 2 (39:42):
That's right. In fact, if you think about it, what
the Higgs field is doing is really not affecting particles directly, right.
It affects the other fields, changes their properties, and then
it's just a consequence of quantum physics that the waves
in those fields come in these unks that we call
quote particles or wavehicles. And then it's a consequence of
(40:05):
relativity that the energy of their vibration has something to
do with mass equals mc squared. The direct link between
the mass of the electron and the Higgs field doesn't
really exist. You have to go through these other pieces,
and that is why in order to explain how the
Higgs field works, I had to explain both quantum physics
(40:26):
to some degree and relativity to some degree in the
book before we could get to that. So, in a way,
the book was about trying to make sure some aspects
of relativity were clear, some aspects of waves were clear,
some aspects of quantum physics were clear, and then bringing
them all together so that we could understand what wavecles are.
(40:47):
And at that point explaining what the Higgs field does
is not so difficult. Just change the frequency of a field.
Changes the frequency of a field, then it changes the
way it vibrates, and that's going to change the mass
of the corresponding particle. That's all. You have to first
understand that electrons aren't like dust particles, and they don't
get their mass through any mechanism that particles could possibly have.
(41:10):
They have to be vibrating objects in order for that
to make any sense.
Speaker 1 (41:14):
And photons, you're saying, are just traveling waves, which means
there is no standing wave for a photon. Photons have
no resonant frequency because the Higgs doesn't interact with the
electromagnetic field.
Speaker 2 (41:26):
Yeah, to be more precise, the electromagnetic field has no
resonant frequency, and correspondingly, it has no standing waves in
empty space, and therefore photons don't have any rest mass.
And yes, one reason for this, let's say, is that
the Higgs field does not directly interact with the electromagnetic field.
But it's important that not only the Higgs field that
(41:46):
we know doesn't do that, but there aren't any other
Higgs like fields that get in the way either. Now,
why is this? Why is it that the electromagnetic field
has this property whereas the electron field doesn't. Why is
it that the electromagnetic field doesn't interact with the Higgs
field and its particles remain massless while the electron field does.
We don't know. We don't have an understanding of the
(42:10):
pattern of which fields the Higgs field interacts with, or
more precisely, we have partial understanding. We understand why Higgs
field of the sort that we have in our universe
can't interact with the electromagnetic field, but we don't know
why we had to have a Higgs field of that
(42:30):
particular sort as opposed to Higgs field of some other sort.
And we certainly don't know why the electron fields interaction
with the Higgs field is weak while the top quarnfield's
interaction with the Higgs field is strong. We don't understand
that pattern at all, and not that there haven't been
many attempts to understand it. I, as a theoretical physicist,
have tried a few times, many others have, and we
(42:51):
have lots of great ideas, but we have no idea
which one of these ideas, if any, is correct, And
we keep hoping that particle physics garments will give us
some clues, and up to now Unfortunately they have not, and.
Speaker 1 (43:04):
It's really crucial because if the photon had even a
tiny amount of mass, it wouldn't have this property that
it's only a traveling wave, which would mean that you
could catch up to it. You could see photons at rest.
You could have like a handful of photons, the way
you could have a handful of electrons, and you could
have them at various velocities, which would mean that observers
(43:24):
wouldn't have to see the speed of light always as
the speed of light. It would feel like a very
different universe.
Speaker 2 (43:29):
It certainly would feel very different because there would be
situations in which light and radio waves from a single
event would arrive at different times. There would be distortions
of things that you see. I mean, you can sort
of imagine if sound waves didn't all arrive at the
same time, if the speed of sound weren't basically a constant.
Just think what would happen to music. You play a
(43:50):
piano and then the low notes arrive late and later
than the I mean, it would make a mess I.
Speaker 1 (43:55):
Thing the cellists have to play ahead of the violinists.
Speaker 2 (43:58):
Speaking would be tough, right, would be a very different world,
and so it is an important feature of our world.
Not only that speeds of different frequencies of light would
be different, but there's another consequence which in a way
might be even more important depending on how much mass
photons would have, which is that the range of electric
and magnetic fields would not be as large. The connection
(44:22):
is not obvious, and the reason has to do with
the following that the way that the Higgs field changes
the resonant frequency of another field is it makes it stiffer.
It makes it more difficult for it to vibrate, but
even more generally, it makes it more difficult for it
to change to vary. And so when you have an
(44:43):
electrically charged object, it can make in our universe an
electric field that goes out into the stars. A planet
can have a magnetic field that goes way out beyond
where the planet is, and that's very important for us
because the magnetic field off the Earth deflects particles from
the Sun that are flung out during solar flares, and
it protects us from the damage that such particles would do.
(45:05):
But if the photon had a mass, or more precisely,
if the electromagnetic field had a resonant frequency, that in turn,
would mean that the electromagnetic field would have more difficulty
spreading out, and magnetic fields wouldn't spread as far, and
so you could end up with a situation where the
magnetic field of the Earth might not reach out beyond
(45:25):
the surface of the Earth, and then we would not
be protected from these solar storms. So you know, we'd
survive because evolution is that way, right, Evolution would find
a way to create life that could survive all of that. Right,
we wouldn't, but we are certainly dependent upon this particular
feature of the universe, and so you know that's one
(45:47):
of the many ways in which the details of particle
physics affect the universe on a macro scale.
Speaker 1 (45:53):
Well, I think my last question for you is to
try to interpret what this all means. You've painted a
picture of the universe as field with waves, and in
your book, near the end, you write the universe rings
everywhere in everything, which I thought was very poetic. But
it makes me wonder, why is this, like, Why is
it that the mathematics of waves, which are very simple
(46:14):
and beautiful, are everywhere. Why are waves all over our universe,
both fundamental and emergent at so many different scales? What
does that say about the universe, that waves are everywhere?
Speaker 2 (46:25):
Well, I think maybe that question has two parts to it.
The first is why are waves everywhere? Even in the
macroscopic universe? Why do we see ocean waves and seismic
waves and waves and rubber And if you look closely
as find waves in metal. If you strike a bell,
there's waves inside. The why is that? And that turns
out to be a consequence of a simple idea, which
(46:48):
is that if I have a substance which is fairly
uniform and spread out like a chunk of metal, then
it is very easy to cause waves to occur. Let's
take the example of just water. Maybe that's simplest. If
(47:08):
you take a huge bucket of water or a big
pond or something, why is it so easy to get
ripples in it? Well, it's because it's so easy to
do something to one little piece of the water. Put
your hand in the water in one place, but that
is then going to have an impact on the bits
of the water right around it, which in turn is
going to have an impact on the parts of the
(47:29):
water right around them. You do something locally to the water,
but then the water can bring that effect outward. Further
and further away from where you pressed on the water
or hit the water, whatever it is you did to it,
And that propagation of an initial effect through this uniform
(47:50):
material almost automatically leads to waves. The math of waves
drops out of the equations, no matter what their details.
Speaker 1 (47:58):
So as long as you have a material where information
doesn't propagate instantly, then you're going to get propagation of
information and those are waves.
Speaker 2 (48:06):
Yeah, and it needs to be a uniform material because
if it isn't uniform, if it's just an agglomeration of
lots of different things, then as things move out, they'll
move out of completely different speeds depending on exactly what
they run into. But when you have a single material
like water or air, the speed at which things propagate
is constant or mere constant, and so as things propagate out,
(48:29):
they do so in a nice uniform way, and that
allows you to get ripples, where you get waves which
are simple and remain simple as they travel. So that's true.
In any material that's uniform, you almost always can get
waves of a certain type. So that's why they're ubiquitous
(48:49):
around us in ordinary materials. Now, if you think the
universe is like a material, it's certainly a uniform leaving
aside places where there's actually stuck. But if you go
out into the deep space, you're surrounded by whatever space is.
It's the same in all directions. It's the same in
all places. And we know this because we can measure
(49:09):
what the laws of nature are by looking at stars
or looking at other things in space, and the stars
are the same basically all across the universe. We don't
see big differences, so we know the universe is remarkably uniform,
and so to the extent it's a uniform material like thing,
the fact that it has waves in it is no surprise.
But we don't know why it's a uniform thing, and
(49:35):
so at some level there's still plenty of why questions
that are out there for which we don't know answers.
That's kind of where we.
Speaker 1 (49:42):
Are, wonderful. Well, tell us again the title of your
book and where listeners can find it if they'd like
to understand even deeper all of these concepts.
Speaker 2 (49:51):
Well, the title I came up with, and I'm delighted
that the publisher accepted it is waves in an impossible see,
beautiful waves being us the stuff we're made from and
the impossible see being this space we live in that's
kind of like a material and kind of isn't. And
the book is available at any of your independent local
(50:11):
bookstores and of course at Amazon and Barnes and Noble
and all the other monsters that are happy out there
to show you the full range of books that are
available in the world. But yes, it's going to be
widely carried in bookstores and you should definitely check it out.
Speaker 1 (50:25):
Wonderful. Well, thanks again very much for coming on to
talk to us about all these incredible concepts and sharing
your particular view of the universe with all of us.
Speaker 11 (50:33):
Thank you so much, Dan, It's been really fun, all right,
interesting conversation there, sort of like a new way to
look at the world and to look at physics and
the nature of reality. Almost.
Speaker 2 (50:45):
Yeah.
Speaker 1 (50:45):
I hope that it gives listeners and readers of the
book a new way to think about these objects that
form the foundations of our whole world. That when you
take your body apart and imagine that it's made out
of atoms and protons and electrons, that you think about
those particles a little bit differently. Maybe you replace your
high school concept of an electron as a tiny little
blue ball with a little ripple in that electron field,
(51:07):
and have a better understanding for what's rippling there and
why the electron has mass, and how it's all connected
to the Higgs boson.
Speaker 11 (51:14):
Well, I was waving in and out of the interview
a little bit. So then the idea is that everything
is a wave. So it was wave, would you say
is a better word to describe what's going on at
the fundamental levels?
Speaker 1 (51:27):
Maths vision is that everything is a wave, a wave
in these things we call quantum fields that we don't
really understand. But if you dig into what it means
for a quantum field to do some waving, it can
give you a better understanding of what motion is, of
what mass is, of what energy is, and how the
Higgs boson gives those particles mass, not by filling the
(51:50):
universe with molasses that slows things down, but by changing
how those fields resonate, which really is what mass is
all about. So standing wave of resonance and a quantum field.
Speaker 9 (52:02):
Mmm.
Speaker 11 (52:02):
Interesting, Well, another cool idea out there, and it may
be a revolutionary way to look at the universe on
this journey to figure out how everything works.
Speaker 1 (52:12):
That's right. Matt Straussler is not just a super smart
theoretical physicist. He really does have a gift for accessible
explanations of deeply important concepts using intuitive ideas. Sometimes he
makes up his own words, like wavehicles because he wants
to avoid the baggage of words you've already heard. But
if you listen carefully and follow along, I really think
(52:33):
it can give you a deeper understanding of quantum fields.
Speaker 11 (52:36):
All right, well, check out his book Waves in an
Impossible Scene. We hope you enjoyed that.
Speaker 1 (52:41):
Thanks for joining us, See you next time. For more
science and curiosity, come find us on social media where
we answer questions and post videos. We're on Twitter, this
word instant and now TikTok. Thanks for listening and remember
that Daniel and Jorge Explain the Universe is a production
(53:03):
of iHeartRadio. More podcasts from iHeartRadio visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Hosts And Creators
Daniel Whiteson
Jorge Cham
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