Listener Questions 63: Hawking radiation, mass, and anti-strings

Daniel and Jorge answer questions from listeners like you! Send your questions to [e-mail]

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Episode Transcript

Speaker 1 (00:08):
Hey, Daniel, if you could throw anything into a black hole,
what would it be?

Speaker 2 (00:15):
I guess it'd be something I don't ever want to
see again, Like a bunch of white chocolate.

Speaker 1 (00:21):
You know that doesn't get rid of the concept of
white chocolate. People can still make more.

Speaker 2 (00:25):
And I'll keep throwing it in the black hole until
they learn.

Speaker 1 (00:28):
But if you throw a white chocolate into a black hole,
does it make it a white hole?

Speaker 2 (00:33):
If it eats matter, it's a black hole. A white
hole would be making matter.

Speaker 1 (00:37):
So if you ever see a white hole out there
in space, it's it's basically a white chocolate fountain.

Speaker 2 (00:42):
If there's somebody on the other side throwing all their
white chocolate into a black hole, then yeah.

Speaker 1 (00:48):
Or does a dark chocolate get turned into white chocolate
on the other side?

Speaker 2 (00:52):
What a cosmic tragedy that would be.

Speaker 1 (00:54):
What if you're in like the five percent of the
universe that doesn't like white chocolate, What if it's cosmically
loved except for a certain household in Irvine, California.

Speaker 2 (01:04):
I don't want to meet those aliens.

Speaker 1 (01:20):
Hi, I am morehy Man cartoonas and the author of
Oliver's Great Big Universe.

Speaker 2 (01:24):
Hi, I'm Daniel, I'm a particle physicist and a professor
at UC Irvine, And yes, I'll meet the white chocolate aliens.

Speaker 1 (01:31):
Aliens are made out of white chocolate, or they like
white chocolate.

Speaker 2 (01:34):
If they're made out of white chocolate, I'll feel so
sorry for them that I'll definitely meet them just out
of pain.

Speaker 1 (01:40):
Well, they probably feel really safe around you because they
know you won't eat them.

Speaker 2 (01:44):
That's true exactly, But they might melt in the sun.
You know, that stuff is just not really very substantial.

Speaker 1 (01:51):
They need like sunshields or something. But anyways, welcome to
our podcast, Daniel and Jorge Explain the Universe, a production
of iHeartRadio.

Speaker 2 (01:58):
In which we take a deep look at both sides
of the universe, the light matter, the dark matter, the
white chocolate, the dark chocolate, the stuff that we're curious
about and the stuff that you are curious about. We
think that everything out there in the universe is a
delicious mystery, and it deserves to have a bite taken
out of it.

Speaker 1 (02:14):
That's right. We try to delve into the deep, dark
mysteries of the universe as well as its shiny bright facts,
the things that scientists and work hard over many years
to discover and figure out how it all works.

Speaker 2 (02:26):
And one of the goals of the podcast is to
take you along on that journey. Puzzling out the nature
of the universe is not just something professional scientists should do.
It's something everybody should be thinking about. We should all
be thinking like a physicist, even if we're not thinking
about physics problems. But those physics problems are fascinating and
are deep and are consequential. Where do the universe come from?

(02:46):
How does it all work? How will it all end?
Where is our place in it? All? These things are
questions that everybody has, and we hope to work together
to find the answer. And that means you should also
be asking questions.

Speaker 1 (02:59):
Yeah, because about the universe are all around us. They
affect us on an everyday basis, and they make us
all curious about what our place in it is? And
where does this all heading?

Speaker 2 (03:10):
Some sort of white chocolate apocalypse that's where we're heading.

Speaker 1 (03:15):
Wait, is that a dark vision of the future or
a bright vision of the future.

Speaker 2 (03:20):
I think people's reactions that will tell us a lot
about who they are deep down.

Speaker 1 (03:23):
Yeah, So if they like white chocolate, they're optimists and
happy people.

Speaker 2 (03:28):
Some of us will run screaming from that kind of person.
But I'm not the kind of person who runs screaming
when I get emails from listeners. I love those emails.
I love hearing your questions about the universe. I love
thinking with you about the edge of your knowledge or
the edge of human knowledge, which listeners often creep right
up into. So please don't be shy send me your

(03:49):
questions to questions at Danielandjorge dot com. We write back
to everybody.

Speaker 1 (03:54):
Yeah, and sometimes we take those questions and we try
to answer them here on the podcast, or at least
we talk about them, which sometimes involves an answer.

Speaker 2 (04:03):
That's right. Some of the questions I get over email.
I think lots of people might have this question, and
so I'd like to share the question and the answer
with the whole podcast community. Other questions I have no
answer to, and so I just hope that we can
fill some time with jokes and speculation in lieu of
an answer.

Speaker 1 (04:19):
So TODA podcast we'll be tackling listener questions number sixty three,
and today we have three pretty awesome questions. One of
them is about hawking radiation. The only one is about
making new matter in the universe. And then we have
a question about the ultimate.

Speaker 2 (04:41):
Particle and the ultimate anti particle.

Speaker 1 (04:43):
Oh wait, is the ultimate antiparticle just the first particle?

Speaker 2 (04:48):
That's basically Brett's question.

Speaker 1 (04:49):
You all right, let's dig into it. Our first question
comes from Andrew.

Speaker 3 (04:53):
Hi, Daniel, and Jorge. This is Andrea, and I have
a question about Hawking radiation. I was interested in something
you said another episode about it being impossible to detect,
and I was wondering if you could talk a bit
more about that, and especially in terms of analysis and
detection and instruments and experiments. For example, have any lab

(05:17):
experiments or simulations already been done to look for Hawking radiation?
If we could develop an instrument, because I imagine this
is just very theoretical at this point, but if we
could develop an instrument to use on a real black
hole in space to analyze the Hawking radiation, what would
that require and what would that look like? Also, would

(05:40):
only some kinds of black holes be feasible for this
kind of analysis, like maybe the one at the center
of our galaxy is too massive? So thank you very
much for taking my question. I love the show.

Speaker 1 (05:54):
Awesome question. It's all about Hawking radiation. You know, can
you have we detected it? Is it just an idea
that we have or is it a proven concept? And
if we haven't detected it, how would you measure it?
And what's at the source of Stephen Hawkins is superpowers?

Speaker 2 (06:13):
I think that was just his sheer sex appeal.

Speaker 1 (06:15):
He admitted rhiz waves.

Speaker 2 (06:18):
That's right, rhiz particles. Actually it's quantum. Yeah, this is
a great question because I love the sort of forward thinking,
like how can we actually figure this out? What technology
would we need? How can we make this practical? Like
me Andrea really really wants to see a black hole
and study it, and this is like one of the
only ways we can really do that.

Speaker 1 (06:37):
Well, maybe you start with the basics, like what is
exactly Hawking radiation and have we seen it?

Speaker 2 (06:42):
Hawking radiation is a super fascinating concept because it's like
a first step between our current understanding of black holes,
which is basically just what general relativity says that matter
falls in it creates an event horizon inside is a singularity,
nothing can escape. Black holes are truly black according to
general relativity. But we know that general relativity can't be

(07:02):
an ultimate description of the universe because it's ignoring quantum effects.
And we know that quantum effects have to be important
when you get really really dense and really really small
things like a singularity. But we don't have a theory
of quantum gravity something that unifies general relativity and quantum mechanics.
It gives us like a description of a quantum black hole.
But Stephen Hawking did something like take a first step

(07:25):
in that direction, and he figured out that if you
have a black hole in our universe, it follows the
rules of general relativity, but also has to follow the
rules of quantum mechanics. And he was able to bring
the math together to make it play nicely. And it
predicts that these quantum black holes are not truly black.
They actually faintly glow with radiation, and that's the Hawking radiation.

Speaker 1 (07:45):
M Wait, so he was actually able to make quantum
mechanics play nicely with special or general relativity. I thought
that was sort of impossible.

Speaker 2 (07:54):
It's hopefully not impossible, because that would mean the universe
can to be understood. It's so far not been achieved
in a comprehensive and coherent way, but there are places
where people have made a few inroads. And so we
call this semi classical because he didn't make a complete
theory of quantum gravity. He just pulls some really clever
tricks in order to do this one calculation without actually

(08:16):
knowing the theory of quantum gravity. So it's a really
slick sort of mathematical maneuver that he did.

Speaker 1 (08:21):
Well, what is it exactly?

Speaker 2 (08:22):
So what he did is he thought about what happens
to quantum fields near a black hole. Now you often
hear in popular science this sort of handwavy description of
Hawking radiation, and the description goes something like a particle
and an anti particle and made near the event horizon.
One falls in the other one is Hawking radiation. That's
not what's going on as far as we know. In fact,
we don't have any understanding of the particle picture of

(08:45):
how this works, because again we don't have that theory
of quantum gravity. We don't know how gravity affects these
tiny particles. What Hawking did instead was think about fields
near the event horizon. A lot of fields have this
property that they can do two things. They can make
particles and they can make anti particles. Or for example,
electroagnetic fields can make fields of all sorts of different frequencies.

(09:06):
And what he did was he said, well, how do
we think about those fields near and event horizon? Because
when you solve field equations, you're thinking about how waves
move through those fields. And the math that he did
showed us that near an event horizon, there's something weird
that happens to those fields. And basically there always has
to be an outgoing wave in order to make the
mathematics work.

Speaker 1 (09:27):
Well, what do you mean like an outgoing wave? What
does that mean? Outgoing in which directing like away from
the black hole.

Speaker 2 (09:32):
Like awave from the black hole exactly. And so that's
what's interpreted as outgoing Hawking radiation, the generation of particles
from the energy of the black hole. That's what this
radiation comes from.

Speaker 1 (09:44):
Now, where does this idea that there has to be
a radiation come from? Is there no explanation to it?

Speaker 2 (09:50):
You can try to make some intuitive sense of it,
but we don't have any microphysics explanation of it. Like
we want one. I can hear that you want it.
I'm sure listeners want it. I desperately want it, Like
what's actually happening? We don't have that understanding because we
don't understand particles and gravity. There's another way to gain
some intuition about it, which is thermodynamically. Think about black
holes as having a temperature. Right, everything in the universe

(10:13):
that has a temperature glows, so black holes also have
a temperature. Then they must also glow. And black holes
because the information that falls in them have to have
an entropy and therefore to have a temperature. And so
that's another way to think about what hawking radiation is.
It's like the black body radiation of a black hole.

Speaker 1 (10:31):
But wait, it sounds like you have to treat the
black hole as a whole if you're talking about entropy
and things like that, So then how is it quantum
as well?

Speaker 2 (10:39):
Yeah, the quantum aspect has to do with these waves,
these quantized fields that surround the black hole, and Hawking
radiation comes from when you have quantum fields and an
event horizon together, you get this generation of waves that
come away from the event horizon. That's what hawking radiation is.

Speaker 1 (10:57):
So it's just I mean black body radiation that happens
when like something you have a hot rock in space.
It's just the molecules and atoms in it are very
excited and so they generate photons that you know shoot out.
Is that kind of what's happening, Like the black hole
is just randomly shooting photons.

Speaker 2 (11:14):
Yeah, that's our microphysics understanding of normal black body radiation.
You're totally right. There's like motion within a rock, for example,
it has some temperature to it, and so photons will escape,
and that's well described by black body radiation. In terms
of a black hole, we don't know what's going on
from the microphysics point of view. We don't understand the
event horizon and can't think about that in terms of particles,

(11:35):
so we have no picture to provide for like what's
generating this radiation other than these mathematical solutions to the
wave equation near an event horizon. You can think about
it thermodynamically also to interpret the black holes having a temperature,
but you don't really know what that temperature means. It
doesn't reflect necessarily the kinetic energy of particles within the
black hole. We don't know how to interpret that because

(11:57):
again we don't have that theory, So we're kind of
black theoretically there.

Speaker 1 (12:01):
Well, what about this idea that you do see in
popular culture and popular science a lot that you know,
at the edge of a black hole, there's two particles
being created. One of them falls in, the other one
spews out, and that's kind of what is hawking radiation?
Does that not happen or we don't know if it happens.

Speaker 2 (12:17):
That could be what happens, but we don't know how
particles operate near an event horizon. We don't know if
gravity is a classical force which would require these particles
to collapse their probabilities, or if gravity is quantum, which
means that it can interact with the various possibilities of
the particles. And so we don't know how to do
those calculations. So we don't know what happens to particle

(12:38):
anti particle pairs near to vent horizon. So yeah, the
answer is we don't know.

Speaker 1 (12:41):
That could be correct, so they could maybe explain what
is hawking radiation.

Speaker 2 (12:45):
There is definitely an explanation for hawking radiation if it
is a real thing in the universe. We just don't
have it. And yes, it could be that one, but
there's no theory behind that. That's just like a handwavy cartoon.

Speaker 1 (12:57):
And what's throwing with handwavy cartoons? Daniel, you can't my
career you're talking about.

Speaker 2 (13:05):
Yeah, they're wonderful, but they're not necessarily accurate and you
can't use them to do calculations or anything. That's all
they are is just a handwavy cartoon.

Speaker 1 (13:12):
Are there other possible handwavy cartoony explanations or is that
the only one that we have?

Speaker 2 (13:17):
I mean, in popular science you'll see all sorts of
descriptions of Hawking radiation, most of which are wrong. The
ones that are most accurate either rely on this thermodynamic
description or Hawking's actual calculation using boundary conditions for waves
near an event horizon.

Speaker 1 (13:32):
But you're saying they're not wrong. We just don't know
what the real answer is.

Speaker 2 (13:36):
Yeah, that's right. It's like the universe has a number
in its head between one and a million, and you
might say, well, Daniel, is it seventy four? And we're like, well,
I could be seventy four, but yeah, I mean, who knows.

Speaker 1 (13:45):
But so far, Hawking radiation is a concept, right, Like,
do have we actually ever measured this at all or
seen it? Or is it just sort of an idea
that physicists think is happening at black holes?

Speaker 2 (13:57):
It's currently still just an idea. We've never seen hawking
radiation and it would be really challenging to ever see
it because hawking radiation is extraordinarily faint for large black holes.

Speaker 1 (14:09):
Are you saying that we haven't seen it, so we
don't know what it is, So it's basically a handwavy cartoon.

Speaker 2 (14:17):
We have lots of theories we have not proven, like
string theory, which is much more than a handwavy cartoon.
Because our physical principles and calculations, you can make predictions,
et cetera, et cetera. So not everything that hasn't been
observed is a handwavy cartoon. But yet we have never
seen hawking radiation, and the challenge is that it's super
duper faint. Like larger black holes are colder, which means

(14:39):
they glow more faintly. So the smaller black hole is
the hotter it is, the brighter it glows. So, for example,
a black hole that has the mass of our sun,
which is already a pretty small black hole, but have
a temperature of sixty nanokelvins, which makes it very dark
and very cold, and any glow it has would be
very very faint.

Speaker 1 (14:57):
Wait wait, wait, what does it even mean to for
a black hole to temperature. Like if a rock is
a temperature, that means it captures you know, the movement
of the molecules inside the rock somehow, right, Like a
hot something hot means that all of its molecules are
moving a lot. They have a lot of kinetic energy.
What would it mean for a black hole?

Speaker 2 (15:13):
Yeah, we don't know. I mean, Thummer dynamics is often
not about the microscopic picture. You don't have to understand
what's going on inside to have these macroscopic descriptions of
entropy and temperature, etc. Really justus sort of like high
level summaries for what's going on inside. Sometimes you can
make these connections, like for the ideal gas law between
the microphysics and the macrophysics. But no, we don't know

(15:36):
what temperature really means for a black hole. There are
some arguments about information and entropy and connecting it to temperature,
but that's a whole rabbit hole that Andrea didn't ask
us about. In this case, you should just think about
the temperature as determining the glow of the black hole.
Higher temperature glows in higher frequencies.

Speaker 1 (15:53):
It glows via the hawking radiation, yeah, exactly, which we
don't know is real or not.

Speaker 2 (15:58):
We don't know if it's real or not, but it
makes predictions. You have this temperature, you can use the
black body radiation curve. You can say, okay, a sixty
nanokelvin black hole would emit this number of photons at
this frequency, and you can look for that. But the
thing is it's very very faint, and so it's very
hard to see. For a couple of reasons. One, black
holes are really far away. That's a good thing if

(16:20):
you want to survive, but a bad thing if you
want to study them. And number two is black holes
are usually surrounded by other really hot stuff that's glowing
very very brightly. So you're looking for a very faint
glow from something otherwise very bright and very far away.

Speaker 1 (16:37):
How faint are we talking about, like basically the equivalent
of how much a rock that is sixteen nanokelving how
much it would glow in the infrared, which is probably
like almost nothing at all, Almost.

Speaker 2 (16:48):
Nothing at all, Yeah, exactly. Now, Andrew asks like, how
could you possibly ever see it? Well, you know, you'd
need super duper sensitive deep infrared sensors and you need
to be near enough the black hole you could which
are some of these rare photons, then you might be
able to pick it out because it would have a
different spectrum than the rest of the stuff, like the
stuff around the black hole, the accretion disk of hot gas.

(17:10):
It's going to glow mostly like in the X ray
because it's very hot, and so if you look at
the very red end of the spectrum and you have
very sensitive devices, then you might be able to pick
this out.

Speaker 1 (17:21):
I wonder if it would get washed in the cosmic
background the noise of light, right, like, aren't we bathed
in infrared light just from the universe sort of glowing?

Speaker 2 (17:32):
Yeah, exactly, we are. That's a great point. The temperature
of that light is around two point seven degreas calvin,
so that's very hot compared to black holes, which tells
you that this would be much fainter and much much
much redder. Now black holes get small, then they do
get brighter. The temperature goes like inverse mass, and so
if a black hole was left on its own, it

(17:53):
would very faintly glow. It would lose mass and then
get brighter. And because it's getting brighter, it's losing mass faster,
so you have this runaway effect where eventually a black
hole evaporates, and near the very end, when it's very
very small, it gets quite hot, and then the hawking
radiation would be visible. So seeing a big black hole
would be difficult. Seeing a disappearing black hole would be

(18:15):
much more possible.

Speaker 1 (18:16):
Well, as it gets smaller, it becomes hotter. So you're
saying it would be admit more photons, but would it
actually be brighter because it's also smaller. I wonder if
if maybe those things would balance out and it would
just be as faint like a tiny black hole a
million kilometers aways. It's about as fant as a giant
black hole that's colder, isn't it.

Speaker 2 (18:35):
The event horizon does shrink, which reduces the intensity, but
the temperature increasing overwhelms that, and so we expect a
smaller black hole to actually be brighter. It's not just
that the frequency of the radiation goes up, but the
intensity of it also will even though the event horizon
is getting smaller, So smaller black holes might evaporate in
a way we could actually see, And people have looked

(18:56):
for this in the night sky because if there were
small black hole holes made during the Big Bang, their
lifetime might be a few billion years. And if they're
just sort of like scattered out in space, not near
some huge source of mass, they could be isolated and
they could be evaporating, and they could glow with these
brilliant pinpricks of light. People have looked for them, nobody's

(19:18):
ever seen one. But that doesn't mean that we won't.

Speaker 1 (19:20):
Like what size are we talking about, Like I imagine
maybe there's like an optimal size for us to see them,
because if they're too small, they're too small to see.
But if they're too big, they're too cold to see.
Is there are wonder if there's an optimal Hawking black
hole size to see.

Speaker 2 (19:33):
The lifetime of a black hole is very very long,
if it's any size at all. Like if you took
a black hole that had the mass of our Sun
and you put it in empty space, it would take
ten to the sixty three years to evaporate. Most of
that time it would be glowing so faintly its mass
would hardly be dropping. A lot of the progress is
made near the end because of the runaway effect. A

(19:53):
much much smaller black hole, of course, could only take
a few billion years so smaller black holes are better
for observing hawking res and that's why people are thinking
about primordial black holes, because stellar collapse or galactic centers,
these produce huge black holes. If you want to see
hawking radiation, you need little ones. That's why people are
looking for black holes that come from the Big Bang,

(20:14):
where it might have made a whole spectrum of black holes,
from super massive ones to super duper tiny ones.

Speaker 1 (20:19):
But don't they also say that at the Large had
drink collider years you're sort of making black holes.

Speaker 2 (20:24):
We are looking for black holes at the Large had
drunk Collider. One idea might be that gravity doesn't behave
the way we expect. If you get things really really
close together, gravity actually gets very very strong. We've never
really tested gravity over extraordinarily short distance scales, so it
might be that if you smash two protons together, when
they get really close together, gravity gets really strong and

(20:44):
it forms a tiny black hole, which would then almost
instantly evaporate but leave a spectrum of hawking radiation which
we could see in our detectors. So we looked for
hawking radiation at the Large hair Drunk Colider but never
seen it. So there's lots of ways you might see
hawks radiation, but yeah, and so far nothing.

Speaker 1 (21:02):
But do you expect there to be black holes? And
in these collisions you're creating? Or I mean, is it
surprising you haven't seen a hawking radiation at the large
Hadron collide?

Speaker 2 (21:11):
Whether you expect to see them depends on a bunch
of theoretical questions we don't have answers too, like are
there additional spatial dimensions? What are the parameters of those dimensions?
You need those spatial dimensions to explain why gravity gets
stronger as things gets closer. And so if for some
scenarios we would have expected to see the black holes already,
in other scenarios we wouldn't have expected to see them,

(21:33):
and so the answer is a bit muddy. Also, those
calculations are even more handwaving than the Hawking radiation calculations themselves,
Like some listeners might think, hold on, you just told
us we don't understand gravity for particles, So how can
you talk about the gravitational force between two protons when
they're really close to each other? And the answer is
we can't. People have done a bunch of back of
the envelopes, sketchy hand wavy cartoon calculations. We don't really

(21:55):
know whether those are right. So it's just sort of
like a, oh, we should look for this in case
it's there. It's not so much that if we didn't
see it, we're sure it's not there. There's lots of
reasons why it might not happen, all right.

Speaker 1 (22:06):
So then the answer for Andra is a tall a
handwavy cartoon Andre. It's like asking for an explanation of
something that we're not sure exists or know how it works.

Speaker 2 (22:17):
Kind of, but we hope one day to see this.
If we do see hawking radiation, that confirms something important.
It tells us that black holes are quantum objects, that
they are following the quantum rules of the universe. They
are not pure general relativistic black holes, that black holes
are not completely black. That would be a huge breakthrough.

Speaker 1 (22:35):
How bright with these black holes getting snuffed out in
the cosmos beat? Would they be visible to the naked
eye or only if you're wearing special glasses or do
you need like special telescopes.

Speaker 2 (22:48):
Yeah, this is the kind of thing we use telescopes
to look for, because you need to see these photons
a very specific frequency range which is usually not in
a visible range. Usually they're in the infrared.

Speaker 1 (22:58):
All right, well, I guess we need to keep looking
at the sky right then, to see if we ever
see these flashes.

Speaker 2 (23:04):
That's right, more particle colliders, more telescopes, more technological eyeballs
to understand the universe.

Speaker 1 (23:10):
Wait, did you just try to hawk more particle colliders?

Speaker 2 (23:16):
Hey, you're hawking your book on every episode, so I
can talk particle colliders.

Speaker 1 (23:19):
All right, Well, thank you Andrew for that great question.
Now let's get to our next question, and it's about
making new matter in the universe, So let's get to that.
But first let's take a quick break.

Speaker 3 (23:43):
Right.

Speaker 1 (23:43):
We're answering listener questions here today, and our next question
comes from Asif.

Speaker 4 (23:48):
Hi, Daniel, and Jorge. This is answer from Tom Finland.
I'm a big fan of the pod and I've been
wondering how difficult is it to generate new matter from energy.
You have previously talked about out how unstabled particles are
able to summon or pull their counterparts out of thin
air to reach a stable configuration again after a collision
in the Large Hadron collider. Doesn't this mean that new

(24:10):
matter is generated from the collision energy. Would it be
possible to scale up this process to keep multiplying the
number of stable particles to produce macroscopic amounts of new matter.
Can we only go in the direction of lower mass
particles this way, or would we be able to somehow
generate all different elements of the periodic table. I'm imagining
a space station orbiting the Sun, generating building materials and

(24:33):
resources to become self sustained, and starting expanding just by
using the available unlimited free energy. I think it's about
time to get this project started, don't you agree.

Speaker 1 (24:43):
Thanks guys, I'm blessing a theme here, Daniel. These are
all particle questions.

Speaker 2 (24:50):
I'm not organizing them anymore. I'm just answering them in
the order they come in. This is just a particle
week over here the podcast.

Speaker 1 (24:56):
But this is an interesting question. I guess the question is, like,
what's actually happening when you collide particles? Because I know
we've talked about it being sort of this magical act
where you know, two things kind of become pure energy
and then matter pops out. And I guess the question
is is the matter that pops out like new matter
or is it possible to create new matter.

Speaker 2 (25:15):
Yeah, it's a really fun question and a great question,
and it goes to the heart of like what is
matter anyway? And if you think about the universe the
way particle physicists do, you know, we have all these fields,
and you can take energy from one field to another field,
and when a field ripples in a certain way, that's
what we call a particle. Then you could just think

(25:36):
about energy sliding around from one kind of field to another.
So you collide one kind of particle with its antiparticle
and that turns into a photon for example. That's energy
moving from like the electron field into the photon field.
Now that photon can turn into something else even heavier
than the original electrons, like a muon and an anti muon.
That's the energy sliding from the photon field to the

(25:59):
muon field. And those different states can have different amounts
of mass, right, So the electron has low mass, the
photon has no mass, the muon has high mass. Mass
is just stored internal energy of some of these states.
So mass is not like a special thing or hard
to make in the universe. It's just a kind of
energy that these fields can have.

Speaker 1 (26:20):
How would you define what matter is or does it
not even make sense to use the word, like maybe
we should just get rid of the word.

Speaker 2 (26:26):
No, it's a good question. I think there's a couple
of concepts of what matter is, which is separate from
the idea of mass. Right, And when we talk about matter,
one sense in which it makes sense is like the
stuff we're made out of, stable stuff which hangs out
in the universe building blocks for our existence. Right, we
are made of matter. We eat things made of matter,

(26:46):
and you know, quarks and electrons come together to make
all this amazing complexity that's matter. Sometimes also extend that
though to other related particles that are not stable, Like
we think of a muon as a matter particle, but
muons last four microseconds before they decay into other stuff.
You can't build anything out of muons. You can't have

(27:06):
life made out of muons or a meal made out
of muons. So I think the concept of matter comes
from the stuff of our experience, and then we extend
it to also similar particles. So since everything we're made
out of is fermions spin one half particles, we tend
to call all spin one half particles matter and other
kinds of particles like photons. We call them force particles.

(27:29):
But that distinction is a little bit arbitrary.

Speaker 1 (27:31):
Like basically, it's all particles in quantum field. But is
there a distinction between the ones we call matter and
the ones that we don't call matter? Is mass is
the thing that makes something be matter.

Speaker 2 (27:41):
The distinction is the spin of the particles. Like all
the particles we call matter, those are fermions. There's spin
one half particles, and all the particles we call force
particles those are spin one or spin zero particles.

Speaker 1 (27:53):
Like are there particles that we don't call matter but
that still have mass?

Speaker 2 (27:57):
Yes? Absolutely there are, like the w and the z bosons.
These are spin one particles. They're not fermions. We don't
call them matter, but they do have mass, in fact
that they're quite massive. They have the mass of like
eighty or ninety times the mass of a proton. Extraordinarily
massive particles, but we don't call them matter. They are
the particles that communicate the weak force. But yeah, we

(28:18):
don't call those matter particles, but they do have mass.
So you can have mass and not be matter.

Speaker 1 (28:23):
And can you be madder without mass? Are there things
that we call matter that don't have mass.

Speaker 2 (28:28):
Well, that's a great question. Until recently, we didn't know
if neutrinos had mass. Neutrinos are in the matter category
because they're fermions. Now we know they do have mass,
but have an extraordinarily small, tiny, tiny, tiny amount of mass.
But no, there are no particles we call matter particles
which are massless.

Speaker 1 (28:46):
And why do we pick the spin of these particles
to be the thing that distinguishes it as matter? Is
that significant to like our existence?

Speaker 2 (28:54):
I don't think it's fundamentally significant. I think we just
noticed that the stuff we're made out of is comprised
of spin one half particles, and that forces tend to
use spin one particles to communicate. But again, matter and forces,
you know, these are sort of colloquial terms. I think
the way you put it is pretty good. Like everything
is just particles in a quantum field, and there's lots
of different kinds of quantum fields that can do all

(29:15):
sorts of weird things. Some of them are spin one,
some of them are spin half, some of them are massless,
some of them are not. There's all sorts of weird
different kinds of fields out there.

Speaker 1 (29:24):
So then I wonder if the ass for us if
is that there's just thing is matter, you know, like
there's only energy that slashes around between these quantum fields,
and sometimes this energy ends up in a quantum field
that we just happen to call matter.

Speaker 2 (29:36):
Yeah, exactly, And so he's totally right that new matter
can be generated from collisions. Like you pour a bunch
of energy into a collision, you can make something heavy.
You can turn that energy into mass, right, and that
can make new matter. So yeah, and principle, you could
like take two protons and smash them together and make
like a gold nucleus if you had enough energy. It's

(29:58):
pretty unlikely. And most of the time when you make
something that's massive from something that's low mass, it's unstable.
Like if you make a w boson or a z
boson these massive particles, then it don't last very long.
Because the universe doesn't typically like to have a lot
of mass or a lot of energy in one place.
It tends to prefer configurations with lots of possibilities, which

(30:19):
tend to prefer configurations with lots of options, lots of
quantum possibilities, and those are the ones with low mass particles.
That's why things decay. That's why muans DeKay down to
electrons or w particles don't last very long.

Speaker 1 (30:31):
Yeah, I don't like to have all of my mass
in one spot.

Speaker 2 (30:34):
Either, exactly, diversified, diversified, diversify.

Speaker 1 (30:37):
Right, No, it just cuts a slimmer figure.

Speaker 2 (30:41):
And that's why most of the stuff we're made out
of it are the lightest particles out there, because they
can't decay down any further. Electrons and upquarks and down
quarks are stable because there's nothing below them on the ladder.
And so yeah, it's possible to take the light particles,
give them energy, smash them together, make heavy particles, but
typically they will not last for very long and less lucky,
and you happen to form something which is stable, like

(31:02):
an iron nucleus.

Speaker 1 (31:04):
Well, I wonder if it's if it's more of a
philosophical question, you know, does the term new matter even
make sense? What does the word new here mean? Like
it didn't exist before, but you know, the energy that
making that matter, it sort of existed before it just
it came from a different field.

Speaker 2 (31:19):
Yeah, that's sort of like the particle of thesus question,
you know, like is this particle new or is this
particle not new?

Speaker 1 (31:25):
Or what does it mean to have an old particle?
Like is there such a thing? Right?

Speaker 2 (31:29):
Particles never retire, man, they work forever, so their age
doesn't matter. I think he's asking about new matter in
the concept of like new elements of the periodic table,
Like could we create elements of the periodic table we've
never seen before by smashing particles together?

Speaker 1 (31:46):
Oh? Like, uh, you think as if it's asking about
creating an element we had never seen before.

Speaker 2 (31:52):
Yeah, he says, generate all different elements of the periodic table.
And to me, the question is, like, well, what are
all the different elements? Even know? There might be some
really heavy new ones that are very stable, that are
very massive we've never made before. And so yeah, and
so if one way to do that is to smash
stuff together and see if we can make those heavy elements,
we haven't been able to do that yet.

Speaker 1 (32:13):
Well, I guess maybe the question then is what's the
biggest or heaviest element we have made out of scratch
in in a particle collision? And I think it means
like spontaneously making something right, not just like you know,
like building up a matter like by adding one proton
at a time.

Speaker 2 (32:30):
I think the heaviest thing we've ever made is element
one eighteen, But that's not really what he's asking about
to do that. You take lighter elements and you like
gently toss protons into them, hoping not to smash them apart.
So that's one technique. But if you just like start
from two protons and smash them together and hope to
make something like element one forty seven, that's not something

(32:51):
we've ever done. When we smash protons together, we don't
ever get helium, for example. It's possible, yeah, absolutely, but
it's very delicate because you put too much energy and
you just destroy the protons and you get the quarks interacting,
you get fragments of the protons flying out.

Speaker 1 (33:04):
No, but I wonder if he means, like, you know,
you take two protons, you accelerate them, you smash him,
you create pure energy, like the old protons are gone,
even the old quarks are gone, and then somehow all
that energy somehow reforms into a complex atom.

Speaker 2 (33:19):
Yeah that's possible, right, and be careful again with pure energy.
That's something we say sometimes, but really what's happening is
that energy is going into another field. Typically it's photons
or z bosons or something. But yeah, then that field
can dump the energy back into quark fields, which could
form protons and make a crazy heavy element. That it's
totally possible. It's not something we've ever done. It's very unlikely.

(33:42):
It requires a lot of things to go right, all
at the same time. But there's nothing saying it's not possible.

Speaker 1 (33:48):
Well, I wonder if you've done it, you just haven't
noticed or measured it or look for it.

Speaker 2 (33:52):
Yeah, that's absolutely possible too, because in these collisions we
get huge sprays of particles, more than we can ever
track or count, and we're not like sift through them
usually to look for new, weird heavy nuclei.

Speaker 1 (34:03):
That the collider is not suddenly covered in gold you
haven't noticed that, or white chocolate? Perhaps, would that be
a tragedy if you like went to work one day
and everything's covered in white chocolate, You're like, no.

Speaker 2 (34:17):
It's an exciting day every day at the particle collider.
Are we going to make a black hole? Are we
going to cover the Earth in white chocolate? Who knows?

Speaker 1 (34:23):
Let's turn it, who knows, Let's find out exactly.

Speaker 2 (34:29):
Let's go as the kids say.

Speaker 1 (34:31):
So then what's the answer for ounce of here? Is
that it is possible to make a matter is just
kind of unlikely.

Speaker 2 (34:38):
Yeah, the answer is that it's totally possible. And I
love your vision of a space station orbiting the Sun
building all sorts of crazy building blocks, but I'm not
ready to invest.

Speaker 1 (34:48):
I see you need to see. The proof is in
the white chocolate pudding.

Speaker 2 (34:52):
Yeah. If this was physics Shark Tank, I would not
be in.

Speaker 1 (34:54):
Ooh, physics shark that.

Speaker 2 (34:56):
I like that.

Speaker 1 (34:57):
Let's make that show.

Speaker 2 (34:58):
All right, listen, bite, let's and designed the pictures a
start the projects.

Speaker 1 (35:02):
Oh, I think they have that already. I think it's
called the National Science Fundation. All right, well, great question. Answer.
Now let's get to our last question of the day,
and this one is about the ultimate particle and possibly
it's anti particle. Let's dig into that, but first let's
take a quick break. All right, we're answering listener questions

(35:35):
and our last question comes from Brett.

Speaker 5 (35:38):
Hey, my name is Brett. I'm full Ty from the
United Kingdom. I'm currently studying an integrated masters and bachelor's
degree in my spare time, and I have a question
for the podcast. I've been thinking about ultimate particles, God
particles and fundamental particles, and I was wondering if there
is a true ultimate fundamental particle that everything else comes from,

(36:03):
would also have an anti version of itself? And also,
if we can't see them now, is it possible that
they're all used up in the Big Bang? And if so,
would we be able to see any evidence in the CMB.
And finally, third part of the question, would it be
the case that different configurations of the particle make up

(36:23):
the ones that we see in the standard model? I
realized this is a bit more than one question, but
thank you for your time and thank you for your responses.

Speaker 2 (36:30):
Hey Bretat, congrats on studying for your master's degree in
physics in your spare time. That's awesome.

Speaker 1 (36:36):
Yeah, that's a pretty cool a master's and bachelor's degree
at the same time. Well, the question is kind of cool,
I guess, you know, because in popular science you hear
talk of the god particle, the ultimate particle, or maybe
finding out that the whole universe is just made out
of one particle. And I think Brett's question is if
we ever find such a particle, would it have an

(36:59):
antipe article version of it?

Speaker 2 (37:01):
Yeah, super awesome question, Brett. The short answer to your
question is, we have no idea because we don't know
the inside these particles, but we can talk about what
the current theories do predict. You know, we suspect strongly
that what we're looking at now, the electrons and the quarks,
are not the fundamental description of the universe. We think

(37:23):
that probably there's some deeper explanation that accounts for all
the weird patterns and like baroque details of all of
these particles.

Speaker 1 (37:32):
Sort of like you know, when we discovered the elements,
we found out there was some sort of order to
them that explain why gold behaved differently than carbon, for example.

Speaker 2 (37:41):
Yeah, exactly, there are these patterns, these features to the
particles that we see. We don't understand them. There are
strong hints that they might be made out of something smaller,
something simpler that explains all of these weird details. Also,
we know that our theory breaks down at a certain
point we have really high temperatures or like we had
in the very early universe, that our current theory just
doesn't work anymore. You need to fold in gravity. We

(38:03):
don't know how to do that, so at some point
our theory breaks down and that very high temperature also
corresponds to very short distances. So the point of the
story is we think our current theory is not complete.
We hope to figure out one day what's there. And
your question is basically, when we do, will that be
some sort of particle antiparticle or is it possible for
everything that made out of something that doesn't have an

(38:25):
anti particle?

Speaker 1 (38:26):
Well, I guess maybe take a step back and let's
think about whether it's possible, Like, is it possible that
everything that we know about electrons, quarks they're all actually
made out of one particle.

Speaker 2 (38:38):
Yeah, absolutely, that's possible.

Speaker 1 (38:39):
What wouldn't mean for the fields right right? Like don't
we talk about the electron having its own quantum fields
and quarks having their own quantum quark fields. That mean
those fields don't really exist, they're just sort of like
made up of other fields.

Speaker 2 (38:52):
It would mean that those fields are effective instead of fundamental.

Speaker 1 (38:55):
Wait, what was that word you said? If they're effective?

Speaker 2 (38:58):
Yeah, an effective field is one that's not fundamental. For example,
if you want to think about like pressure waves in
a material, you can write that down in terms of
a field theory. Wave equations for how oceans work. But
we know that oceans are not a fundamental field in
the universe. Right, we can still think about waves in
the ocean as if the oceans are a field. But

(39:19):
that's just like useful mathematics that describes a lot of
complex stuff, sweeping it under the rug without really understanding
the details. So we don't know whether the fields we
have now are fundamental fields or they're just effective fields.
It could be that there is no electron field, that
there's something deeper the squiggly on field or several squiggly
on fields, and when you zoom out a little bit

(39:41):
and so you can't see the squigglions anymore, they act
like an electron field. So you can use the electron
field as an effective theory. It works, it's helpful and
lets you do calculations, but it might not be a
true description of the deepest nature of the universe.

Speaker 1 (39:56):
Whoa so like all this time we thought the electron
field was a fundamental and like basic feature of the universe.
But no, it could just be an illusion kind of.

Speaker 2 (40:05):
It might be an emergent phenomena. Right, this is something
we see all over the universe that you can describe things,
lots of different scales. You can talk about galaxies without
understanding the particles inside every planet and inside every rock. Right,
you can zoom out and find simple mathematical laws. Kepler
discovered those without even understanding gravity. Right, you can find

(40:26):
simple mathematics that lots of different length scales, distance scales,
energy scales in the universe. That's sort of a mystery,
like why that's even possible, But yeah, you can zoom
in or out in the universe and find mathematical laws.
We don't know if we found the deepest layer yet,
or if there even is a deepest layer, or what
that looks like.

Speaker 1 (40:45):
Well, what would make more sense? I guess would it
make more sense for there to be like all these
multiple fields electron field, quark fields, muan fields, or would
it make sense to just have one field to rule
them all.

Speaker 2 (40:59):
It's a great philosophical question. We don't have a scientific
answer for it, right.

Speaker 1 (41:03):
What do we have a song? Though?

Speaker 2 (41:07):
We don't have a song or a scientific answer for it.
Maybe there is a song for all the particles. I
don't know, but you know, if this is the fundamental theory,
there is nothing below it that means that there's a
lot of unanswered questions, you know, like why are there
three copies of every particle electrons, muons, and towels, all
sorts of questions that are out there that would be unanswered,
and you might just be like, h, I don't know,

(41:27):
that's just kind of the way it is. You'd be
much more satisfying if we found a simpler explanation, because
simplicity is always more satisfying because there are a few
work follow up questions, but we don't know. The universe
is not required to be satisfying to our minds.

Speaker 1 (41:41):
I wonder if you could maybe like start with one
field and then try to invent or figure out how
that one field could give rise to all the other fields.
Is that something that people have done and discount it
or is that basically what string theory is or what?

Speaker 2 (41:56):
Yeah, that's basically string theory. String theory says the whole
universe it's man out of one kind of thing, a string,
and that string can do lots of different things. They
can vibrate in different ways, so it's sort of like
a meta field theory. Instead of having ten different quantum
fields or eighteen quantum fields, you have a string which
can oscillate in different ways, and different modes of those

(42:16):
strings correspond to the different fields that we see. So
string theory can describe everything we see out there. It
can even unify gravity and quantum mechanics and describe everything.

Speaker 1 (42:28):
But I wonder if you need to get that complicated,
because I know string theory is super complex, right, it
has like a bazillion dimensions to it. Couldn't you just
start with like the danelon or something and then try
to create one particle that's not a string, like a brierrating,
just a particle, and then try to come over with
the rules that would make electrons and quarks.

Speaker 2 (42:47):
Yeah, you definitely want the simplest explanation, right. The reason
that people do string theory is that it is kind
of the simplest way people have made all these pieces
work together because there's a lot to describe. You know,
we have all these different particles or the daniel On field,
whichever has to be able to do lots of different
kinds of things. That has to be able to wiggle,
like an electron and a muon and a towel, and

(43:08):
the neutrinos and the quarks and all the force particles,
and it has to be able to explain quantum gravity,
so you need gravitons in there as well. And string
theory is sort of the simplest way people have ever
made that work. A simpler theory can't explain everything that
we see so far, and it's pretty simple. You just
got one string.

Speaker 1 (43:26):
Well, I guess. Then the question is, can a string
in a string theory have an anti version of itself?

Speaker 2 (43:32):
Yeah, that's a really cool question. And you know, somebody
might one day come up with a theory of some
fundamental thing that explains everything and has an anti fundamental thing.
But this current idea of string theory doesn't have anti strings.
And the whole idea of anti particles I think is
sometimes a little bit misleading. It tells people that, like,
there's an opposite kind of matter, instead of thinking of

(43:55):
antimatter as an opposite kind of matter, thinking of it
as like a complementary kind of matter, or think about
it as like fields can do two different kinds of things.
Your favorite band can play rock, they can also play
alternative the electron. Fields can wiggle in an electron like way,
you can also wiggle in an anti electron like way.
It's just another thing. The same field can do. They're
just strings. They can wiggle to make the electron field,

(44:17):
which then can make electrons or anti electrons. So the
short answer is there are no anti strings in string theory.
You don't need them because the strings can make the field,
and the field can do either the particle or the
anti particle.

Speaker 1 (44:30):
Well, I know, and we've talked about it before. How
like an antiparticle, something is just the same thing except
what the charge. Charge is flipped And so I guess
maybe I wonder if the question is do strings have
a charge? Is such a thing as charge in string
theory or is charge something that comes from the different
vibrations of the string.

Speaker 2 (44:49):
Yeah, charge is something that comes from the different vibration
of the string, because the same string can make a
charged field like the electron field, and a non charge
field like the electromagnetic field. And so that tells us
something about like what charge is in the universe. Currently
we imagine charge is conserved in the universe. But if
charge things are made up of the same stuff, is

(45:10):
not charge things, And you could might imagine you might
be able to convert one to the other. You might
be able to destroy or create charge by getting the
string to wiggle differently.

Speaker 1 (45:19):
It sounds like maybe you're saying, you know, if we
ever discover the ultimate theory of everything, it wouldn't have charges,
in which case it wouldn't have an anti version of itself.

Speaker 2 (45:29):
Yeah, I think I'd pull back on that a tiny bit.
I'd say it doesn't have to have charges. It might.
There's no guarantee that string theory is the right description
of the universe. There's lots and lots of problems with
string theory and lining it up with reality and figuring
out which string theory to use, et cetera. Somebody might
come along with a much better, you know, rubber band
theory of the universe, or the whohe On theory of
the universe that might have Antijoheans in it. Who knows,

(45:53):
So I'm not ruling it out. I'm just saying, we
don't know, but our best current theory doesn't require anti strings, right,
you can out.

Speaker 1 (46:00):
But I wonder like, if you do get to that theory,
like the whorehe On theory of everything, and there's a
plus Horray and a minus horhe, if them wouldn't just
ask like, why is there a plus oriy and a
minus hoorge. There must be something even deeper explain the
plus and minus warges, right, in which case you couldn't
call this the ultimate theory.

Speaker 2 (46:19):
Maybe, and you'll have a hard time ever proving that
you have the ultimate theory because you can almost never
distinguish between the two scenarios of we have the ultimate
theory or we don't have the ultimate theory, but we
don't have the power to see inside this one. You know,
it's a question of resolution always, like can you zoom
in far enough to tell what this is made out of?
Can you tell whether it's made out of itself or
something smaller? But you could also end up in a

(46:41):
situation where you have a theory with a plus Jorge
and a minus Orge, and you understand why that there's
a symmetry to it, it's a balance to it, or there's
some sort of structure to it that demands requires a
plus and a minus. So it might be that the
question is answered on its own without going to a
deeper theory.

Speaker 1 (46:58):
But who knows, well, I guess for it to have
an anti version of itself, you would have to kind
of pick one as the dominant one, right, kind of
like because we only call antimatter antimatter because it's not
the same as the kind that we're made out of.

Speaker 2 (47:13):
Yeah, and that's not something we understand in our universe.
Like why we tend to be made out of one
half of this symmetry and not the other half. That's
a huge open question.

Speaker 1 (47:22):
Well, any theory of everything that has me at the
center of it, For me, I think that's the ultimate theory.

Speaker 2 (47:27):
That's everything.

Speaker 1 (47:28):
Let's just stop right there. Yes, if I'm at the
center of the universe, let's not look any further.

Speaker 2 (47:34):
Forget Aristotle, forget Copernicus. We have the whoreey theory, the
whoregey centric theory of the universe.

Speaker 1 (47:40):
That's right, Yes, that's all you need.

Speaker 2 (47:43):
Nobody tell the Catholic Church.

Speaker 1 (47:44):
And at the core of it is just to handwavy cartoon.

Speaker 2 (47:50):
It's a good way to live, man, Yeah.

Speaker 1 (47:53):
I know, all right. Well, I think that's the answer
for bread, which is that it is possible if we
find the god part or the ultimate particle of matter
in the universe and forces that it might have its
own anti particle, it's anti god particle. Would it be
the anti god particle or the godless particle?

Speaker 2 (48:13):
The devil particle. Yeah, who knows, But the dog particle
I like that better.

Speaker 1 (48:18):
Yeah, but then are we made out of dog particles
or God particles?

Speaker 2 (48:22):
I want to be a cat particle. I don't know,
but I love that Brett is thinking about this. I
want everyone out there to think about the deep nature
of the universe. You don't have to be a professional
physicist or even on your way to becoming one. This
is a mystery that belongs to everyone.

Speaker 1 (48:35):
Yeah, we hope everyone has questions and also anti questions.

Speaker 2 (48:39):
Are our answers anti questions?

Speaker 1 (48:40):
To Zach Can, they're definitely anti answers most of the time.

Speaker 2 (48:45):
Well, I hope when we collide our anti answers with
your anti questions, we're not annihilating your curiosity. That's right.

Speaker 1 (48:51):
We're just creating positive why.

Speaker 2 (48:53):
Is all over the place and hoping it matters.

Speaker 1 (48:56):
All right. Well, I think that answers all of our questions.
Thanks to everyone who sent in their questions. We always
enjoy talking about these adventures into people's curiosity. We hope
you enjoyed that. Thanks for joining us. See you next time.

Speaker 2 (49:16):
For more science and curiosity. Come find us on social media,
where we answer questions and post videos we're on Twitter,
this Org, instant and now TikTok. Thanks for listening and
remember that Daniel and Jorge Explain the Universe is a
production of iHeartRadio. More podcasts from iHeartRadio, visit the iHeartRadio app,
Apple Podcasts, or wherever you listen to your favorite shows.