Listener Questions #8

Daniel and Kelly answer questions about electron spin, quantum fields, and cellular vaults!

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:06):
Do electrons only spin up and down? Or can they
spin sideways too? Our cells contain quadrillions of vaults, What
on earth do they do?

Speaker 2 (00:16):
Particles are ripples in quantum fields, So can a field
exist without them? If you knock on vaults? What does
it do to the mouse immune system?

Speaker 1 (00:25):
Well, an electron that turns right always turn right? Why
is dark chocolate better than whites?

Speaker 2 (00:31):
Biology? Physics, immunology, forestry. Uugh, you can never really escape chemistry.

Speaker 1 (00:37):
Whatever questions keep you up at night, Daniel and Kelly's
answers will make it right.

Speaker 2 (00:41):
Welcome to another Listener Questions episode on Daniel and Kelly's
Extraordinary Universe.

Speaker 3 (01:00):
Oh.

Speaker 1 (01:00):
I'm Kelly Wienersmith, and I'm a parasitologist, and I am
learning that there's all kinds of biology topics that I
just didn't even know existed. And I'm super excited about
today's episode.

Speaker 4 (01:09):
Hi.

Speaker 2 (01:09):
I'm Daniel. I'm a particle physicist, and I always knew
there was lots of biology I didn't know anything about.

Speaker 1 (01:15):
I guess it's good to know what you don't know.

Speaker 2 (01:18):
But my question for you today, Kelly, is when was
the last time one of your kids asked you a
biology question you didn't know the answer to. Oh, not
a daily occurrence over there in the Wienersmith household.

Speaker 1 (01:29):
You know, I can't say my kids care about biology
that much. I don't. My daughter has been reading these
manga books about like cells biology, and like, we keep
buying her manga books on physiology and anatomy. And I
remember a couple years ago and I was looking through
the biology section at Barnes and Noble, and I saw

(01:50):
these manga books and I was like, who is the
audience for this? Who wants to read mangas about cell biology?
And the answer is ten year old girls. And she
is absolutely eating it up. But she was explaining to
me how cells come from other cells and blah blah blah.
And so I know these days I'm asking her the questions,
you know, because maybe she knows more about cell biology
than I do, as we'll learn today.

Speaker 2 (02:11):
That's amazing. I love the idea of educational manca, like
manca as a way to teach science. What a great idea.
That's fantastic.

Speaker 1 (02:19):
She is eating it up. What about you? When was
the last time your kids asked you a physics question
you didn't know the answer to.

Speaker 2 (02:24):
Oh that happens all the time now because my son
is taking physics in high school and his girlfriend is
taking epiphysics, and so they come to me with tough
physics questions all the time. And I got to sit
down with a piece of paper and like, Okay, what's
going on. You got a bullet hitting a block attached
to a swing, which is the whole thing is tied
to a squirrel which is running around a bicycle wheel.
I mean, like, these problems are insane.

Speaker 1 (02:47):
Yikes. Do you usually get the answer?

Speaker 2 (02:49):
I always do figure it out eventually, you know there's
a method to these problems. I kind of like that actually,
And when I teach physics here at you See Irvine,
I'm often doing problems in front of like a five
hundred person class that I've never seen before because I
think it's useful for the kids to see me mess
up and make mistakes, or like say, I'm gonna try
this with energy. Oh no, that doesn't work, let's back up.

(03:09):
Or I'll get the wrong answer and then I'll have
to try to figure out why, because I think it's
useful for them to see somebody figuring out where things
went wrong and backing up.

Speaker 1 (03:17):
Yeah, absolutely, And if I don't know the answer, I
never pretend. I'm always like, what do we need to
do to figure out what the answer is? We'll start
with Wikipedia, but then we got to check it, and
so here's how you search Google, scholar and blah blah blah.

Speaker 2 (03:30):
Exactly, because science is not a list of facts. It's
a process for learning, right, and you've got to teach
the process exactly. I totally agree.

Speaker 1 (03:37):
Yeah, Well, our listeners are teaching us a lot with
their questions lately. Today I'm excited. I got a question
about an organelle that's founded almost all eu caryotic cells,
and I was like, what this exists? Then I had
never heard of it before.

Speaker 2 (03:51):
So you went and you bought the manga on this thing,
and you learned all about it.

Speaker 1 (03:55):
Right, it would be a pretty short manga, as we're
gonna discover today because actually there's not a lot that
we know about this. But you know, maybe manga will
be my preferred way of learning about things going forward.

Speaker 2 (04:06):
Well, one of my favorite ways to learn about the
universe is to get asked a question from a listener
that I don't know the answer to, which makes me
go and dig into it. In detail, and often when
people write us questions, which you are all very welcome
to do to questions at danielan Kelly dot org. If
I do know the answer, all right, right back. But
if I don't, I'll delay the answer by saying, hey,
let's talk about that on the podcast, which gives me

(04:27):
a week or so to do some research and find
the answer. So that's what you can be hearing about today,
some questions that either I didn't know the answer to immediately,
or questions we thought lots of people might want to
hear the answer to.

Speaker 1 (04:38):
I feel like you've given our secret away. But that's fine.
It's true. Whenever we get a question, I'm like, oh,
we'll do it on the show. That does mean I
have no idea.

Speaker 2 (04:47):
We're sharing the process to Kelly, right, not just the answers.
It's all about the process, that's right.

Speaker 1 (04:52):
That's right. We'll be transparent.

Speaker 2 (04:54):
So send us your questions to questions at Daniel and
Kelly dot org, not Daniel and Kelly dot com. That's
a very US couple who we hope are having a
very nice wedding.

Speaker 1 (05:03):
We wish them the best.

Speaker 2 (05:04):
Congratulations Daniel and Kelly. All right, but aswer your questions,
and on today's episode we have some really fun questions
about quantum spin, about little bits of the cell, and
about quantum fields.

Speaker 1 (05:20):
Let's do it, all right, Daniel, First, once for you.

Speaker 2 (05:23):
Our first question is from Bertus, and he's asking a
question about the spin of particles, which gives me a
great opportunity to try to disentangle a lot of misconceptions
about quantum spin. Here's Bert's question.

Speaker 5 (05:35):
Hey, guys, I know when you measure the spin of
an electron you get up or down. What about if
the electrons spins perpendicular to the axis of the measurement,
is it still only up or down? Anything in between? Thanks?

Speaker 1 (05:51):
Oh, so this is great. So you and I have
had multiple conversations about electron spins and you've mentioned many
times that the spin is up or down, but it
never occurred to me, Well, why is it bupper down?
Why can't it be perpendicular? And I just you know,
so explain yourself.

Speaker 2 (06:07):
Daniel. That's a great question because it makes an opportunity
for a nice teaching moment where you can back up
and try to untangle a misconception about how electron spin works.
And the thing that birds not understanding. Will dig into
this in more detail, is that electrons don't like have
a spin, and then you measure it along some axis.
There really just are two possibilities for the spin. But

(06:30):
let's dig into it and first understand, like, what are
we talking about when we say quantum spin, right, And
Quantum spin is a strange little property of quantum particles
that we don't really understand. It's something that we try
to describe using our intuition for other stuff, like how
things spin in our world, like you see a ball

(06:51):
spinning or the Earth is spinning around the sun, and
so we try to describe this weird new property and
analogy to something we are familiar with, and we're doing
this all the time physics, right, Like photons are weird
and new, so we describe them as kind of like
a particle and kind of like a wave because they
have kind of particle eproperties and kind of wavy properties.
Quantum spin is something weird and new we've never seen before,

(07:12):
but it does have a lot of similarity to the
kind of spin we're familiar with, so that's why we
call it spin. But it really isn't the same thing, all.

Speaker 1 (07:21):
Right, Where to start from there in what ways is
it similar to what we see?

Speaker 2 (07:25):
Yeah, great question. The thing that makes us call it
spin is that it's similar to spin in that it
seems to create magnetic fields. Like when you have a
charged particle like an electron, and you move it in
a circle, like you have a loop of wire for example,
that creates a magnetic field. That's how an electromagnet works.
How you can run current through something and create a
magnet And that's like the basis of motors and all

(07:47):
sorts of stuff. So stuff moving in a circle, charges
moving in a circle create magnetic fields. Cool. But then
we discovered that little tiny particles also have their own
magnetic fields, like electrons. When they're not moving in a circle,
they have a little magnetic fields. And we notice this
because if you shoot an electron into a magnetic field,

(08:07):
it gets deflected either one way or the other way,
which means it must have a little magnetic field of
its own, and it can't have like a magnetic charge. Right.
We talked about on the podcast once how there's no
like magnetic charge in the universe. All magnetic fields are
created by electric charges moving in a circle. So people thought, well,
the electron has an electric charge. Maybe if it's spinning,

(08:32):
then that's effectively the same as a charge moving in
a circle, and that would create a magnetic field. Like
if you took a sphere of metal that had electric
charges on it and you spun it, that would create
a magnetic field. So an analogy, people are like, well,
maybe the electron is spinning. That was the first idea
to explain the little magnetic field that particles have.

Speaker 1 (08:52):
What are they sitting?

Speaker 2 (08:55):
So then people thought, well, that makes a lot of sense, right,
and then they sat down to do the calculation. All right,
if an electric is spinning, well, how fast is its
surface going, Like what's the speed of the surface of
the electron? And then they realized, oh, actually that would
be going much faster than the speed of light. So hmm,
that doesn't quite work. Plus a lot of people are like,
electrons are points. Points can't spin. There's nothing to spin

(09:19):
there if it's like really zero volume, so it can't
be physically spinning. You shouldn't have the image in your
mind of like a tiny little beach ball that's actually spinning.
But it's something very related to spin because it does
create magnetic fields and it participates in conservation of angular momentum.
Like we talk about lots of times on the podcast,

(09:39):
how anglar momentum is conserved in the universe. Like, if
you have something spinning in space, it will keep spinning
until something slows it down. The same way if something
is moving in space, it'll keep going until something slows
it down. Well, that angular momentum, what you can do
is you can turn it into particle spin. You can
like sap the spin of some physical object and turn

(09:59):
it into particle spin. So particle spin really is a
kind of angular momentum because the universe allows you to
slosh like orbital angular momentum into quantum spin angular momentum.
So it behaves a lot like spin, and it is
a kind of angular momentum, which is why we feel
justified like calling it a spin. But it's not like

(10:22):
a physical spin. It's something fundamentally different.

Speaker 1 (10:25):
You see what I got? Okay, so it's not spinning.
But we need to explain why. When you send an
electron at a magnetic field, it goes one way or
the other way, and there's only two options. And angular
momentum is if you send something off in a certain direction,
it just keeps going.

Speaker 2 (10:40):
That's linear momentum. Angler momentum is if you spin something,
it just keeps spinning.

Speaker 1 (10:46):
Thank you. If you spin something, it just keeps spinning.
And I'm still not getting the connection between the angular
momentum spin and why the electron goes one way or
another way when it hits a magnetic field.

Speaker 2 (10:56):
So the angular momentum comment is just to convince you
that spin is a kind of angular momentum because the
universe treats it like that. Like the universe requires that
angler momentum is not changed. The amount is the same.
Like you can have stuff banging into each other, you
can do all sorts of interactions. Whatever anglermentum has to
be conserved. The amount before some event is the same
as the amount after some event. Cool. But there are

(11:18):
different kinds of angular momentum, right, Like you can be
spinning in place, you can be running in a circle.
All those things are angle momentum, and it can slash
back and forth from one kind to the other. And
this is just to say that the universe includes particle
quantum spin among the possible kinds of angle momentum. So
stuff has to be conserved, but it can slash into
this category as well. So that tells us the universe

(11:41):
considers quantum spin to be a kind of angular momentum
when it's doing its accounting, and it requires anglermentum to
be the same before and after. Quantum spin is one
of the possibilities. So it's like when you put a
thousand dollars in your bank account, you expect it to
still be there when you come back. Maybe it's moved
into checkings, maybe it's moved into savings. Whatever, it's still
one thousand dollars. This is saying the universe treats this

(12:04):
as the same kind of accounting as it does other
things which are legitimate physical spin, like orbits and running
in a circle and whatever. The universe treats all these
accounts as if it's just dotted lines that are the
humans draw between stuff. So that's what makes it say
it really is a kind of spin. Now the second bit,
it can only go one way or the other. That's
the quantum piece, And that's what Burtis is asking about,

(12:25):
because when you send electrons into a magnetic field, you
don't get a whole spread of outcomes. It's not like, well,
if the spin is all the way to the left,
it goes one way, and if the spin is all
the way to the right, it goes the other way.
But you can also get answers in the middle. What
they saw when they did these experiments in the nineteen
twenties was very clear. They either go left or they
go right. There's no electrons that go through the middle
and nothing in between. That's what's quantum about the spin.

(12:49):
It's either up or it's down. And that's what Birth'
question is, like, well, what happens if the spin is perpendicular,
which way does it get measured? And that's sort of
what Birth's question is.

Speaker 1 (13:00):
So you've got an electron. You look at the electron
before you send it to the magnetic FID. Can you
predict if it goes left or right or no? Because
you've observed the electron and something collapses and physics is impossible, you.

Speaker 2 (13:13):
Can predict if you measure it spin. If you measure
it spin and the spin is to the left, then
you know it's spin is going to be to the left.
When it goes to the magnetic field, it's going to
go to the left. So yes, you can measure the
electron spin beforehand and know it. You can also leave
it uncertain and maybe it's left or maybe it's right,
and then you'll know when you send it into the
magnetic field. That's when the universe decides, Oh, this one's

(13:34):
going to be left or this one's going to be right.
So yes, you can observe it.

Speaker 1 (13:37):
But if it's not spinning, how do you know if
it's up or down? If you don't send it into
the magnetic field and then see what it does.

Speaker 2 (13:44):
Sending it into a magnetic field is the only way, right.
Oh yeah, So if you have like two of these
in a row right, and say, for example, you send
it through one who goes left, you're like, okay, now
I know it's left. You send it through another one
of those same devices, it's still going to go left
because you're measured it left, it is left.

Speaker 1 (13:59):
Got it all right? And angular momentum is concerned exactly,
always go exactly. Okay, got it? I'm with you. What's
the answer that.

Speaker 2 (14:06):
The answer is that you shouldn't think about the electron
is having some true spin direction the way the Earth does.
Like the Earth has an axis around which it's spinning right,
call it the north pole. And you might ask, look, well,
I'm going to measure it spin along this axis. Is
it more up or is it more down? And that's
going to give you my answer. The electron doesn't have
some true spin angle and you're just measuring the projection

(14:29):
of that along some axis. There's only two possibilities for it.
It's either up or it's down. That's what it means
to be quantum, not that there is some true continuous
set of values that are hidden from you and you're
just getting a discrete answer. It's not like electrical engineering
where you have like analog waveforms that you're then digitizing
into zeros and ones. It is either zero or it

(14:49):
is one, and the in between state is having a
probability of being zero and a probability of being one.
It's not like there some arrow there that you're projecting
along the axis. True spin state can't be perpendicular. It's
just not an option. It's either up or it's down,
or it's a mixture of those two possibilities.

Speaker 1 (15:08):
Not a lot of options front.

Speaker 2 (15:11):
And you might think, Okay, well, I'm just gonna measure
the spin state along the X axis, and then i'll
measure along the Y axis. Then I'll measure along the
Z axis and then I'll sort of know it in
three D. The amazing thing is the universe doesn't let
you do that because you can't know the spin direction
in two axis simultaneously, the same way you can't like
no position and momentum simultaneously. The universe prevents you from

(15:32):
knowing that it's like undetermined thanks to the uncertainty principle.
If you measure the spin along X, you get either
up or down, right, left or right. If you then
measured along Y, it scrambles it in X. So let's
go back to that experiment we talk about. Say you
send it through the magnetic field and it goes left.
Now you have another set of those magnetic field devices,
but you've rotated in ninety degrees, so it's like selecting

(15:53):
along a different axis, and now it goes like up
or something. So it's gone left and then it's gone up.
Now send it through the original device again, and you
might think, well, I know it's left right. It was
left before. It's got to be left again. But no
measuring it along the up down axis has scrambled the
left right information, and so now it might go right.

Speaker 1 (16:12):
So that doesn't sound very conserved, Daniel, what happens.

Speaker 2 (16:18):
What happens is that the interaction has scrambled the angler momentum,
so the machine itself has absorbed some of that angler momentum.

Speaker 1 (16:25):
Physics is trippy.

Speaker 2 (16:26):
Physics is trippy. So the bottom line, Bird is that
you can't think about the spin of this particle number one.
It's a physical spin. It's a quantum weird thing which
is similar to spin, but not really exactly the same.
And you shouldn't think of it as being like some
true vector that you're then projecting into X or y
and that has some like true valley that could be perpendicular.
It can never be perpendicular. It's either up or down

(16:47):
or some mixture of those two. There is nothing in between.

Speaker 1 (16:51):
All right, Wow, a rare instance where physics has a
clear answer. Ooh oo oooh slice. But let's see if
it's it's intelligible, all.

Speaker 2 (17:01):
Right, brut tell us if we clarify that or just
confused you.

Speaker 5 (17:04):
Hey guys, as always, thanks for the great explanation. Love
listening to your podcast.

Speaker 1 (17:25):
All right, So onto something completely different. We got this
amazing question from Ryan about an organelle that I didn't
even know existed. So let's hear Ryan's question.

Speaker 3 (17:35):
Hi Kelly, Hi Daniel, Thank you both so much for
your wonderful show. I've just become aware of the existence
of this cell organelle called the vault. I'm so surprised
and fascinated that a structure that's apparently so common in
cell biology should be so mysterious to us still, and
that it was discovered so recently. Also, what a name

(17:58):
for something so mysteriou is the vault? It'd be great
if you guys could bring us up to speed on
the state of the science and the understanding in relation
to this crazy little thing. What do we think therefore,
how did they get there? And how did they avoid
our detection for so long?

Speaker 1 (18:19):
Thank you so much, Daniel. Have you ever heard of
the vaults?

Speaker 2 (18:23):
I've never heard of the vault. I've never heard of
a part of the cell that started with the before,
like the mitochondria. I guess the nucleus. It seems especially important.
But I'm also just not one hundred percent clear on
what an organelle is. Is it a miniature piece of
the cell in analogy to like how my liver is
an organ in my body. It's like a specialized component

(18:44):
of my body is an organelle, like a specialized part
of the cell that does one particular job.

Speaker 1 (18:49):
Yes, yeah, that's a great definition.

Speaker 2 (18:51):
So why they call it organelle? Is it like organito
or something like that?

Speaker 1 (18:55):
I think yes, I think it is like organito.

Speaker 2 (18:57):
I think organito is cuter.

Speaker 1 (18:58):
Yeah, I no, I agree. I don't know who we
write to submit these recommendations to, but let's get on
that all right.

Speaker 2 (19:04):
So tell us about the organito called the cell? What
does it do? Why does nobody know anything about it?
How come I've never heard of it before?

Speaker 1 (19:10):
It's all amazing, Okay, So you find it in u
caryotic cells. So these are cells specifically that have nuclei
that have a membrane and like so inside the DNA
is sort of stored inside these nuclei. So like when
we talk about prokaryotic cells, we're talking about bacteria and
Archaea and just about like everything else is eukaryots. So
it's like everywhere, and it's bigger than a ribosome. So

(19:34):
like I think most of us learned about ribosomes in biology.

Speaker 2 (19:37):
I don't know if I should be impressed by that,
because I don't know how big a ribosome is.

Speaker 1 (19:41):
I don't really have a good like gut intuition for
how big a ribosome is, but I do know that
in cell biology or in biology, I was taught the
thing that looks like sort of like a big thick squiggle,
you write ribosome next to that. The point that I'm
trying to make is that it is bigger than a
thing that we have known has existed for a really
long time, and so it's surprising that we didn't also

(20:03):
know that this existed for a really long time.

Speaker 2 (20:05):
So not really crazy tiny. It's not like it's hiding
because it's super small. It's like kind of a big component.
It's like not understanding what a toaster is in your kitchen.

Speaker 1 (20:14):
Yeah, exactly, that's right. It's big enough to see and
there are lots of them. So there's like ten thousand
in each cell. Whoa, yeah, so in our body you
might have as many as one hundred and sixty quadrillion
vaults in you.

Speaker 2 (20:27):
What that blows my mind.

Speaker 1 (20:30):
I know they're huge, and so what they are. So
it looks like if you've ever been in a cathedral
and you've looked up at the ceiling. The folks who
discovered this organelle felt like the ceilings of a cathedral,
which are sometimes I think called vaults, kind of looked
like this organelle, but it would be like two of
them put together. So to me, it kind of looks
more like a barrel and the inside is empty and

(20:50):
it's mostly made out of three proteins, and then it
has a little bit of ribonucleic acid in it, so
a little bit of RNA.

Speaker 2 (20:58):
So hold on, I have to totally adjust my mental
picture here because when you said the vault, I was
thinking of a safe that there's some like deep secret
about life in the universe stored inside ourselves, and today
we're gonna crack al Capone's vault or something like that.
Now you're telling me I have to replace it with
like the idea like a little capsule. It's like a
little thing that holds stuff. So it was a little
bit like a container.

Speaker 1 (21:17):
Yeah, and it's empty in the inside. So yes, you're
your thought. I mean, we are not going to crack
al capone safe today. That is for a bit of
a spoiler, we have not really cracked the vault yet.

Speaker 2 (21:26):
Let's get Heraldo on the show and maybe you'll help
us out.

Speaker 1 (21:29):
Oh yeah, yeah, let's definitely recommend Heroldo's shows to our listeners.
All right, So you've got this like compartment. You have
loads of them, and it was discovered for the first
time in nineteen eighty six, Wow, by Nancy Kadersha and
Leonard Rome. And the reason they discovered it was an accident.
So they were looking at vesicles, which are these little

(21:50):
things that you find in cells. They're another organito that
sort of moves things around. And while they were trying
to like get a bunch of vesicles together for their experiments,
they looked in their sample and they were like, oh,
there's all of this like contamination, and it was a
little bit hard to see, but they were like, okay, well,

(22:11):
let's try to get the contamination out. And then they
realized like, oh wait, this isn't contamination, this is something
else that was in the cell. And they realize the
reason it had been missed for so long is because
when you're trying to look at the inside of the cell,
you often put stains inside of a cell that binds
the RNA, and the vault is only about four percent RNA,

(22:31):
so it's staining, but it's staining in a very like
light and easy to miss way. So a bunch of
people had been looking at the stuff that stained with
the RNA, like the vesicles and missing the vaults. So
this group just got lucky that they happened to like
get the vaults with the rest of their samples of vesicles,
and that they noticed this like junk in the background.

Speaker 2 (22:52):
And they weren't using staining, so they didn't miss the vaults.

Speaker 1 (22:54):
They were using staining, but they looked at the sample
close enough, and instead of ignoring what looked like junk
in the back background, they were like, wait, that junk
all has like the same shape and there's a lot
of it. What is that? And then they were like,
holy crow, a whole new organelle.

Speaker 2 (23:09):
Wow. I think that says something really powerful about science,
that you know, often what we do is imperfect, and
we tried like the only possible thing first because we
can get some information, but then we sometimes forget that
that's limited or that it's made some assumptions, and we
don't always go back and like re explore that understand
like what are we missing if this is the only
thing we're doing. You know, it's sort of like the

(23:29):
example of like, well this works in mice yeah, yeah,
we can do it in mice, doesn't mean that it's
going to work anywhere else. And we've learned something universal, Right,
it's fascinating to then crack these doors open. What was
that moment like for them? Do you think that they realized, like, wow,
all of this is actually something fascinating.

Speaker 1 (23:45):
It sounds like they were pretty excited by that moment,
And yeah, I agree, like what we know about biology
is limited by the tools we have, and sometimes we
don't even realize that our tools are limiting what we
know about But my sense is they were pretty excited,
and they actually had the lab members they all sort
of like pitch different names for what to call it,
and they had a little bit of a contest.

Speaker 2 (24:06):
Do you have the alternatives? That would be amazing.

Speaker 1 (24:08):
I wasn't able to find the alternatives.

Speaker 2 (24:11):
Organito face wasn't up there.

Speaker 1 (24:15):
Oh man, society has been robbed of that opportunity. But
the vault is a pretty sweet name.

Speaker 2 (24:22):
I think it's very cool, Yes, very dramatic.

Speaker 1 (24:24):
Yeah, And so, as I mentioned, it's found in eukaryotic cells,
and it's found in like very similar ways in all
of these eukaryotic cells. So often when you find something
in biology, and you find it in lots of places,
and in all of those places it looks exactly the same.
That suggests that evolution is doing something to stabilize it. Like,
this has a really important function. We're not going to

(24:45):
tinker with it because tinkering with it can break it.
You need this, it can't.

Speaker 2 (24:49):
Be broken, and it's common across eu caryots. Means it
provides something really basic. Right. This isn't like, hey, this
makes the wings on a hummingbird really really light. This
is like essential to some foundational part of life. Right.

Speaker 1 (25:02):
That was the initial hypothesis, which to me seems totally reasonable.
And there are some places where it's been lost. So
for example, fruit flies, which are like, you know, a
model that's studied in biology all over the place, and yeast,
which is also studied a lot, they don't have vaults
for reasons we don't understand. So it's got a bit
of a spotty distribution, but most organisms do have it. Okay,

(25:25):
so what do we think done?

Speaker 2 (25:26):
Yeah, tell us Colleen, crack the vault open for us.

Speaker 1 (25:29):
Yeah. So the answer is, actually, we don't know. So
biology biology, I know, it depends. So one hypothesis is
that it's important for transporting toxic stuff that's in a
cell out of a cell. And the reason we think
that is because there are people who have tumors and

(25:51):
when they've gotten their chemotherapy or there are various drug treatments,
it looks like the vault isn't involved in making those
drugs work less well by shuttling it out of the
tumor cells. And so the thought was that this vault
is going around and anytime there's something bad in the cell,
and chemotherapeutic drugs can be pretty toxic, you know, they're
trying to kill cancer cells, the vault would like put

(26:14):
it in the middle of the vault, shuttle it to
the outside of the cell, and then dump it back
outside of the cell. But you know, chemotherapeutic drugs were
not like a common part of our evolutionary history and
they exist not in the rest of the animal kingdom
for the most part. So the idea is that maybe
anything toxic they move. There's some thought that they're important
for like the immune response, like maybe they could encapsulate

(26:35):
a virus and shuttle that outside of the cell. There
was an observation that the vault connects to the inside
structure of the cell. So the cell has like essentially
what you'd think of as like a lumber structure that
sort of like holds it up. It's got scaffolding, and
it was attached to it, and so there was some
idea that maybe it attaches to that and moves around
the cell and transports things like take it from the

(26:57):
nucleus and bring it to another organelle orgin eto. But
at the end of the day, we don't actually have
a good answer. And so one of the guys who
helped to discover it, whose last name is Rome, he
joked that actually the purpose of the vault is to
fund his lab because he had spent fifteen years trying

(27:19):
to figure out a function. And they have some like
tantalizing associations, but at the end of the day, no
one has been able to pin down this is what
the vault does, and we're sure and this is his
main function.

Speaker 2 (27:32):
Well, help me understand why it's so hard to figure out.
I mean, I understand, like when we're talking about quantum particles,
one of the challenges is that you can never really
zoom in and see them and watch them. But here
we're talking about like kind of big biological things that
you could, in principle see under a microscope. Why can't
we just like watch as sell in action and say, like, oh,
I see what the vault is doing. Like imagine you

(27:53):
come into a city as an alien, You're like, what
are all these male people doing. Oh, they're going from
house to house delivering letters. You'd figure it out by
watching what they're doing. Is that not possible for some
reason or oversimplifying it? Why can't we just watch the
vaults and figure it out?

Speaker 1 (28:07):
Yeah, So here's my best guess as someone who doesn't
do cell biology. So a lot of times what's important
is important in the system that it's found. And so
for example, if you're studying this in a mouse, you
can't watch what's happening inside of a mouse cell while
it's still inside of the mouse. And so if you
really want to understand what it's doing. Often if you
just take a mouse sell out, for example, and you

(28:29):
put it in a dish, then it can't do a
lot of the stuff that it usually does, Like if
it's involved in the immune system, it's you know, can't
signal with the other cells.

Speaker 2 (28:36):
And then native question because to image a mouse sell
you have to remove it from the mouse. You can't
like put a whole mouse under a microscope and say, like,
I'm going to look at this cell on the surface
and see what its vaults are doing.

Speaker 1 (28:46):
That's right. Yeah, So to stain and see what's happening
inside of a cell at that level, I think we
still need to put it under very specialized microscopes and cameras,
and it can't be inside of the mouse while it's happening.

Speaker 2 (28:58):
Well, there's your answer. We need to develop technology for
a whole mouse microscope.

Speaker 1 (29:02):
There you go, there, you get right, and then if
we could see that, then maybe we'd have all of
our answers.

Speaker 2 (29:06):
All right, So you've got to take the mouse sell
out do specialized stuff. Then that changes what the cell
is doing, which makes a lot of sense. So we
don't necessarily get a clear picture of the cell in
its actual action.

Speaker 1 (29:17):
And I don't actually have enough experience with imaging to
know how easy it is to stain things inside of
a cell that are this small and then still watch
what's happening inside of cells like in live time. It's
possible we might have to indirectly do things like somehow
make a cell or figure out a cell line that
makes more vaults than another, and then expose those two

(29:39):
different cell lines to chemotherapeutic drugs, and then you can
say like, Okay, this cell line split the chemo therapeutic
drugs out more than the other cell line, and this
one had more vaults. And so you know, you're indirectly
trying to figure out what's happening based on the responses
without being able to actually like be in there watching
everything happening in lifetime.

Speaker 2 (29:58):
Wow, So out, what are people doing right now to
study it? What is the room lab writing grants about
right now?

Speaker 1 (30:05):
According to an article that I read that came out
through the Royal Society, the answer is pretty much funding
agencies have gotten tired of paying for trying to figure
out what the vault does when they have no answer.
And so doctor Rome, I think, is emeritus now, so
he's retiring and trying to get other people excited about it.
I'm going to step back really quick and mention some

(30:26):
mouse works. So you wanted to know, like, how do
you study this? So one of the ways that we've
studied it is we knock out the information needed to
make the proteins in the vaults, and then you look
to see what happens to the mice that are missing
these proteins. And this is what I think was the
most interesting when I was doing the research. So when
you like knock out one of the proteins, maybe tumors

(30:47):
grow a little bit more in those mice if they
have cancers.

Speaker 2 (30:50):
And just to be clear, knocking out means removing the
genetic code so that the cell doesn't know how to
make the vaults anymore.

Speaker 1 (30:56):
Exactly or make a component. So we mentioned at the
beginning that the als are made out of three main proteins,
So if you're knocking out the code to make those proteins,
then maybe you'd get a vault that is like you know,
it's like a basket that's missing some of the weaving
because one of those proteins is missing. So it was
a little bit associated with tumor cell size. There was
another one that was a little bit associated with immune

(31:17):
system functioning, and when you knocked it all out, maybe
the mice grew a little bit more slowly. But like
you know, the initial prediction was that this must be
crucial for life because you see it everywhere and it's
so conserved by evolution, but you knock it out and
the animals seem okay, And so what is this doing?
And so I don't know what the answer is. No

(31:39):
one does. But you know, I wonder, is there's something
that we haven't done to these mice in the lab yet, Like,
you know, if you expose them to radiation, do they
all just like die immediately? Is there something that we
haven't tested yet? And under those conditions vaults are crucial.
But at the moment you can knock this stuff out
and the animals seem to do okay without them.

Speaker 2 (31:57):
Well, here's the sort of basic evolutionary biology questionesting that
it's conserved, which you must mean it has an important function.
I think the implicit argument is out there in the
wild is probably getting knocked out cosmic rays or random mutations.
And if it didn't serve a function, then those knockout
animals would thrive. But would they necessarily be selected for? Like,

(32:18):
is there an advantage to not making the vault? If
there's no cost to making the vault, can't you just
sort of stick around and hang out as part of
our genetic code?

Speaker 1 (32:26):
Yeah, okay, so let me see if I understand the question. So, first,
I'll note that if you make one hundred and sixty
quadrillion of these, there's probably some cost to making that
many of them, and there's something we're not understanding. So
maybe something that I'm about to say is wrong and
we just don't realize it. But if you make that many,
it seems like there's got to be a cost, and
if they weren't producing some function that was pretty regularly

(32:47):
needed by organisms, you would expect them to not keep
paying that cost, right, Okay, So for radiation to knock
the vault out, it would have to mess up cells
that are inside of the new gleist that code for
the proteins in the vault. Like, I don't know how
often that's happening, so I'm not quite sure I'm a
understanding the radiation part of your question.

Speaker 2 (33:07):
I was just wondering if nature has done these experiments
essentially removing the vault from animals through random mutation or
radiation or whatever, and then competed those no vault organisms
against the vault organisms, And I was wondering why, if
there's no benefit to the vault, the no vault organisms,
which must exist also in nature, hadn't outcompeted everybody else.

Speaker 1 (33:27):
Yeah, that's a great question, and that might be where
the vaultless fruit flies and the vaultless yeast came from.
And I think there's plants without vaults. So I think
an important question for biologists to ask is do we
actually need these All these organisms can live without them,
and why are the rest of us holding onto them
if they seem so inconsequential. Why are we making one

(33:48):
hundred and sixty quadrillion of these things if we don't
really need them? And I don't think we know.

Speaker 2 (33:53):
And maybe that's why I'm so tired of the evenings,
right because I spent my day building all these vaults.

Speaker 1 (33:58):
That's right, that's right. Wait, give it a break, body.
We don't need these things, and they're not even good
when you have cancer. Sometimes you asked what are people
working on now? I did come across a variety of
papers where people are trying to figure out how to
take advantage of the fact that you have this organelle
that's empty in the inside, that is maybe able to
move around the cell and deliver things from place to place.

(34:19):
Could you use it as a way to deliver drugs
if you could sort of hijack its use. So folks
are now trying to figure out if vaults can be
used to our benefit in some way, even though we
don't know what their initial purpose is supposed to be.

Speaker 2 (34:31):
I'm imagining like those little capsules that you can send
through the hydraulic tubes or I guess the air pressure
tubes at banks and stuff like that. That'd be pretty
cool to take advantage of that.

Speaker 1 (34:39):
I loved those so much when I was a kid.
I'd have my mom pull up a little farther so
that I could be the one to press the button.
And oh man, it was better in the eighties and
the nineties. No, it wasn't.

Speaker 2 (34:49):
So if we're still discovering essential components of the cell
that make up a significant fraction of its volume, are
there still things that we haven't figured out their discoveries
in the future, like big parts of the cell that
we have never seen. For whatever reason, I.

Speaker 1 (35:03):
Feel like there's gotta be Like I have this vague
memory of not that long ago, there was like another
major nerve that was discovered, and I think the idea
was that we had like mapped out the nerves in rodents,
and so we thought we knew where they all were.
But turns out humans have another one that we had
sort of missed until recently, and which is not too surprising.
But I do think there's still surprises left to be uncovered.

Speaker 2 (35:25):
Yeah, well, that's what makes biology exciting, right. Not only
is it super relevant, but there's lots of unanswered questions.

Speaker 1 (35:31):
Right. And speaking of unanswered questions, Rian, is this giant
shrug that we're sending your way sufficient to answer the
question that you sent us?

Speaker 3 (35:42):
Let's find out, ah, Kelly, Wow, as far as shrugs go,
that was spectacular. Yes, if you're gonna have a non answer,
it can be a non answer full of so much
interesting information. I think that's even better than knowing what
it is. What an incredible mystery. We have quadrillions of

(36:02):
these things, and the answer so far is maybe they
don't do much at all.

Speaker 4 (36:08):
Wow.

Speaker 3 (36:09):
Wow, that's gonna keep me thinking for ages. Yeah. That's brilliant.
Thanks so much. I knew you guys would make something
great out of this, and I'm so glad I found
something that was new to you as well. I'm definitely
gonna refer to them as organitos from now on too.
That's adorable.

Speaker 6 (36:25):
Thank you, Okay, we are back and we are answering
questions today from the tiny little things in your cell

(36:47):
to the tinier little things that they.

Speaker 2 (36:49):
Are made out of. And now we have a question
from Kurt about particles and fields and what's possible out
there in the universe.

Speaker 4 (36:57):
I know in quantum mechanics there are fields and can
become excited to form particles, like you got the electromagnetic
field with the photon, the Higgs field with the Higgs boson.
Could there be a quantum field where it's not possible
to form a particle. I've never heard of such a thing,
so was wondering if there always must be at least
one particle for each field. Thanks.

Speaker 1 (37:18):
Ah, this is another one of those great questions where
it made me think, oh, yeah, I've heard Daniel say
stuff over and over again and never thought, oh, well,
what about blah blah blah. So I guess I had
always thought of quantum fields as being sort of like
a wave, and I guess that makes me think of
the ocean, and ocean waves have ripples. Is a field

(37:41):
more like a blanket held taut without ripples? Like what
does a field look like?

Speaker 2 (37:47):
Yeah, that's a great question. And the answer depends on
the temperature. Like in the early universe, when all the
fields were totally filled with energy, a big, frothing mess.
It was more like the ocean, and you wouldn't think
about like individual drops to it didn't really make sense.
But now the universe is old and cold and dilute,
and the energy is mostly spread out, and for most
of the universe the fields are empty. It's more like

(38:10):
a dried up sea bed with a few droplets on it, right,
And those droplets are what we call particles, And so
it sort of depends a little bit what phase of
the universe we're talking about. But I want to congratulate
Kurt on asking this question for exactly the reason that
you just mentioned. I think to really understand something, you
have to ask yourself questions about it. You're like, all right,
you're telling me it works like this, but then what

(38:30):
about this scenario or what about the opposite, or does
this have to be true? And it's that process of
like turning it around in your head and poking it
from all sides that builds that model in your mind
that lets you then manipulate it and then become fluent
in it and that's what doing physics is. So congrats Kurt,
and I want to encourage everybody out there when you
hear an explanation on the show, really try to do that.
Say does this connect with this other understanding or what

(38:52):
are the limitations or in what situations does that break down?
And if it's not connecting in your head right to me,
I will help you sort it out, or.

Speaker 1 (39:00):
We will sort it out for other people, because I
think a lot of times when the listener has a question,
that's a question that a lot of people have either
thought or if they didn't think it themselves, when you
say it, they're.

Speaker 2 (39:10):
Like, oh yeah, what about yeah exactly.

Speaker 1 (39:12):
Which was certainly my response when I read this question.

Speaker 2 (39:15):
So let's dig in by reminding ourselves what we mean
when we say particles are ripples and quantum fields? What
is that anyway? And it's sort of a historical tour
through what we've thought about particles, And check out our
whole episode on what is a particle anyway? The short
answer to which is we're really not sure, but we
have some models for it that are probably wrong. But
you know, his hysics somehow a head of biology, but

(39:41):
still getting nowhere. So intuitively, you might think of a
particle as like a tiny little dot of matter, and
that's what we thought, like one hundred and fifty years
ago discovery the electron. We're like, okay, there's something inside
matter that has spin and charge and mass and all
this kind of stuff, So start with a little dot

(40:01):
of manner. But then we saw that these things were
actually controlled by wave like mathematics, you know, we saw
interference effects. We're like, it doesn't really make sense to
think of this as a tiny speck. It's really more
like a wave. Then we introduce this quantum wave function,
which is controlled by the Schrodinger equation and tells particles
where to go essentially, and we have this confusing particle

(40:23):
wave duality, which I think is more misleading than clarifying,
because really it's all about the wave. The particle is
the observation where you see the wave, but the wave
controls everything. It tells you where the particles can go.
Like in relation to quantum smin as we were talking
about earlier, the wave function tells you do you have
a forty percent probability of going left or sixty percent
probability or a zero percent probability? The wave controls everything.

(40:47):
We discovered like fifty years ago that there was also
sort of an important limitation there, which is it really
only lets you think about one particle, Like you have
an electron flying through space. You can describe the wave
function of it and what's going to happen whatever, And
it's hard to talk about two electrons or twenty electrons,
and what about electrons that are being created and destroyed constantly.
It's sort of like trying to tell a story about

(41:09):
one electron, but it's really just part of a larger tapestry.
And now you have lots of stories you're trying to
all tell. People found a way to unify all those
individual stories together into a field theory. So rather than
talking about any individual particle, they're like, let's think about
all these different waves as part of one bigger sheet there.

(41:29):
Instead of having this wave over there and that wave
over here, let's integrate them into being ripples in one
unified field.

Speaker 1 (41:36):
So when I'm trying to picture a ripple, should I
picture a bunch of electrons? And like, you know, so
I'm thinking about like a sine wave even like the amplitude,
is it a bunch of them coming together? To form
an amplitude or is each wave a separate particle? What
constitutes a ripple?

Speaker 2 (41:55):
I think the closest description is that each wave is
a separate particle, and art with a classical field theory
like electromagnetism, we say that photons are ripples in electromagnetic fields.
And Maxwell understood this long before we had quantum mechanics,
and he thought about photons as like, Okay, you have
a ripple propagating through the electromagnetic field. But let's be

(42:16):
clear about what that means, because a lot of people
are imagining something moving like a sign wave, like it
moves up, it moves down, it moves up, it moves down.
That's not what's happening, right. A photon moves in a
straight line. What's oscillating is the field. What is a
field anyway? Exactly? A field is a number at every
point in space. So imagine a cube of blank space, right.

(42:38):
All you have in your mind right now is just
a black cube, and then at every point in that space,
put a number. There's a seven here, there's a zero there.
It's mostly zeros, right, So put all zeros in your field,
and put a one in one spot and then how
that one move through the field. That's a ripple in
a field. Right now, you can describe the relationship between

(43:00):
numbers of different points in space using a mathematical function.
So instead of having a one, have like a one
and then a zero, and then a minus one, and
then a zero, and then a one and then a
zero and then a minus one. That's like a sine
wave right now. It's not moving up and down. It's
the values of the field itself that are described by
the mathematical function. So that's the ripple. It moves along

(43:21):
the line like a photon moves in a straight line.
It doesn't go up and down or side to side
or anything like that. But the values of the field
along that line are changing. And a photon is more
complex than just one number. It's a vector, so at
every point in space it has a direction as well
as a magnitude. You don't need to understand that in
all of its detail. But the point is the particle
is a ripple in the values of the field. It's

(43:43):
not physically wiggling through space.

Speaker 1 (43:45):
Got it, all right? I feel like I have a
much better visualization now.

Speaker 2 (43:48):
All right, So that's classical electromagnetism and understanding the photon
is a ripple in that field. But what we do
now are quantum fields. We say, all right, the field
can't just have any value, like at that point in
space you could have a zero or one, or a
zero point seven, two nine, or a one point four
to twenty seven. There are only certain values allowed. There's
a ladder of possible values, and so you can have

(44:12):
like a zero, or you can have a one point seven,
or you can have a three point four, you can
have a fourteen point one. There's a certain set of
values there that are allowed, and those are the ones
that are solutions to the quantum equations. Like quantum equations
don't have solutions for every value. They have a ladder
and that comes out of the mathematics of quantum field theory,
and it comes from constraints and boundary conditions. And you know,

(44:33):
we don't have to necessarily get into why quantum field
equations have only certain values, but they do. And when
you take a classical field theory and you quantize it,
what that means is you're imposing the mathematics on it
that generate only a certain spectra of solutions. So now
you have your quantum field, and it can either be
zero or it can have the first solution or the

(44:54):
sex and solution or the third solution, and we call
that having zero particles or one particle, or two particles
or three particles. So the number of the step you
are in the latter is the number of particles we
consider in the field.

Speaker 1 (45:06):
Okay, so inside of that box, there's a finite number
of ripples that could happen because there are steps and
you can only take certain steps. And it's a big number.

Speaker 2 (45:16):
Not necessarily a finite number. You could have an infinite number,
but they're discrete, right, There's not any possible number could
be a solution. There might be an infinite number of solutions, right,
but there are gaps between the solutions.

Speaker 1 (45:27):
All right, got it?

Speaker 2 (45:28):
And so that's what we say. Like the field is
in state two, that means there are two particles. The
field is in state nineteen, there are nineteen particles there.
So that's what we mean when we say the particle
is a ripple in the field. It means that there
are solutions to the field equations, and they're just like
the Schrotinger equation, but they're sort of generalized to describe
more than one potential particle, and they can describe multiple

(45:49):
particles moving through the field, like photons. The electromagnetic field
can have lots of photons. There are lots of photons
in the universe. There are all ripples in the same field.

Speaker 1 (45:56):
Right, What is a particle, It's a state in the field.
So state in the field just tells you how many
particles are in the box, or how many particles are
possible at a particular location in the box.

Speaker 2 (46:10):
Yes, so at any particular place in the field, there
are solutions, and those solutions are localized because particles aren't
the whole universe. Some of them are actually bigger than others.
Depends a little bit on their momentum, Like if you
know it's momentum really really well, then it's uncertain over space,
and particles can actually be spread out across really vast
distances in the field. That's a whole other confusing thing.

(46:32):
But essentially you can have particles at different locations, but
at each location you can say I have one particle
or two particles, And some fields can have multiple particles
in the same place on top of each other, like
you can have nineteen photons in the same place the
field is fine with that. You can't do that for
electrons because electrons are different kind of particle. They're fermions.
They don't like to occupy the same place at the
same time unless they have something else about them that's different,

(46:55):
like their spin is different or something. So they obeyed
different sort of quantum rules because the field itself is
different and so the solutions come out differently. So some
fields you can only have zero one particles. Other fields
you can have like as many particles as you want, okay,
And there's lots of different kinds of fields. Like the
simplest field is the Higgs field. The Higgs field is
just a number in space. You might hear described as

(47:16):
a scaler field. That's what it means. It means just
a number. Scaler is a fancy way of saying a number.
Other fields are spinner fields, which are like numbers, but
they also have another dimension which can be up or down,
like electrons we talked about, kind of spin up or
spin down. There's spinner fields they have two possible numbers there,
and there's vector fields like photons have three possible numbers.

(47:37):
And there's even more complicated fields that you can have
a tensor. A tensor is like a vector, but more
like a matrix, right, So it's like many possible values there,
So it gives very complex behavior. And if gravity, for example,
is a quantum field, people think it has to be
a tensor field, which makes the graviton a very complicated
particle with five possible spin states, et cetera.

Speaker 1 (47:58):
No wonder, y'all haven't figured that out yet.

Speaker 2 (48:00):
Gravity is hard anyway. Fields can do all sorts of
really complicated stuff. They can interact. You can get energy
going from one to another, which is how we describe
particle interactions. But at the end of the day, when
we say a particle is a ripple, we mean that
there is a field there with a ladder of solutions,
and the number of particles is sort of like which
solution are you on? If you're on the fourth solution

(48:20):
from the bottom, we say there are four particles there.

Speaker 1 (48:23):
All right, So it sounds to me like in order
to have anything that qualifies as a field, there has
to be some particles there, right. The answer can't be
zero in every location.

Speaker 2 (48:35):
Yeah, it's a great question, Kurt asks, and your answer
is actually really cool. One I mean, I think Kurt
is asking if there's a field where you couldn't possibly
have particles. It's totally possible to have a field that's
empty of particles, where there's possibilities for particles, you just
don't have the energy, right, there's just not enough energy
to make any particles. That's totally possible. I think Kurt's
asking a different question, which is, could you have a

(48:56):
quantum field where no particle is even ever possible, where
just can't do that kind of ripple. It's a really
interesting question because you might think, like, well, particles are
a special kind of ripple in these fields, and it
has to solve the equation, and could you have a
field whose basic properties prevent there from ever being any
solution like that? Like are there fields with no solutions

(49:17):
at all? And it's a really good deep question about
quantum field theory. The answer is basically no, because the
simplest field you can imagine like the Higgs boson, but
then even remove all of its interactions, the simplest field
has to have some kinetic energy, has to be able
to wiggle. That's what fields can do. And as long
as you have a field that can have kinetic energy,

(49:37):
and it basically motion, and then you can find quantum solutions.
So essentially every quantum field, by its nature, has quantized solutions,
and steps on that ladder are particles, and so essentially
every possible quantum field has particle solutions to it. Even
the very simplest scenario, even the most basic, minimalized, bare

(49:58):
bones field, would have particles in it.

Speaker 1 (50:01):
What I love about this question is that it seemed
like it was going to be very simple. Even simple
questions can be deceptively sort of complicated to really understand
them completely. But I learned a lot. Let's see if
Kurt did.

Speaker 4 (50:16):
I also learned a lot. Thank you so much for
the response. I found it quite interesting and thought provoking.
I haven't thought about how quantum field theory generalizes from
the simpler classical field description with Turner's equation, the idea
that each solution to the field equation corresponds to the
number of particles. That makes perfect sense. Your answer helped.

(50:37):
Thank you.

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