Episode Transcript
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Speaker 1 (00:07):
So I was outside the other night with my son
looking up at the sky, and we were having a
great time, and he turned to me and he asked
me a question. He said, Hey, Dad, why are there stars?
You mean like movie stars? No, No, why astronomical stars?
He wanted to know. Wow, what did you say? Well?
I thought he was asking me, like, why do stars exist?
(00:27):
You know, why do we have bright stars in the sky.
So of course I give him a long physics explanation
for you know, how funion works and all this kind
of stuff. I wonder what it's like to have your
dad be a physics professor. It's awesome. It's awesome. I
wonder how many times he's just like dad. I just
wanted a one sentence answer. I once heard him explaining
(00:48):
to his friends about black holes, and I thought, Hey,
that dude is cool because of me. I think cool
as might not be the appropriate adjective here. But what's
the What's he satisfied with your explanation? No? Not at all.
In fact, it turns out I totally misunderstood his question.
When he asked why are their stars? He didn't mean
(01:10):
like why does the star burn? He meant like, why
are their stars? Plural, like why don't we just have
one star? Right? Or like why isn't everything just spread
out smoothly in the universe? Why does things clump together
to make planets and stars and all that stuff? WHOA,
That is a good question. Yeah, it's a great question.
It's a kind of question kids ask, right, the kind
of question you don't necessarily think to ask. It's such
(01:32):
a basic, simple question. That's a question I have. And
I'm I'm definitely not five years old. Ye I am
(01:55):
Morhan and I'm Daniel, and welcome to our podcast, Daniel
and Jorgey Wayne the Universe, in which we try to
take everything or anything in the universe, even the obvious
stuff like stars, and explain it to you. Why is
it there? How does it work? Do I have to
worry about it? Can I buy one online? We try
to answer the smooth questions and also the lumpy questions.
(02:16):
And today is going to be a bit of a
lumpy episode. Today on the program, we're asking the question
why are there stars? The universe has a really strange
kind of shape. I mean, it's huge, but it's mostly empty, right,
Like there's vast distances between stars and even vaster ones
(02:38):
between galaxies. But then you have these hot little points, right,
all this matter concentrated in these little dots. It's a
really weird arrangement. Why is it concentrating these little pin points?
Why isn't more diffuse or why don't all those pin
points just clumped together? Yeah? Why don't we have just
one mega star or like a big pudding of delute
(03:00):
gas everywhere? Right? Why is the universe the way it
is and not any of those other ways? It could
have been those ways in some alternate multiverse. It probably
is those ways, but in those multiverses they don't have
awesome podcasts to ask this question. Yeah. Yeah, because you
look at the night sky and it's beautiful, right, I
mean it's it's like this black void with little white pinpoints.
But you gotta wonder why does it look that way? Okay,
(03:23):
so I have to take a digression here an artistic
question for you or here, which is why do you
think we find the night sky beautiful? I mean, I agree,
it's gorgeous. This is the best view in the universe, right,
But is it necessary do we find it beautiful to
be evolved to find it beautiful? Is it just chance? Like?
Could we have evolved in a way. We look up
at the night stine, We're like, yuck, that's gross. M h. Well,
(03:45):
I think we have a innate appreciation for sparkly things, right,
we like we'll all pyromaniacs. Yeah, no, I mean evolved
evolved from liking water maybe or being attracted to water
or spark the water. I don't know, sparkling water. They
had ivan then caved mondays right, Yeah, I think people
(04:07):
used to carbonate their own water back in cave men days.
I'm pretty sure that we should have asked that question
Ryan North when we had him on the podcast. When
did they invent sparkling water? The greatest invention all time?
Sparkling water. That's a great question is why are there
stars and planets as opposed to just having a monotonous,
(04:30):
monogamous no homogeneous, monochronous, monochromatic Yeah, I mean like a
plane universe. I guess why do we have stars and
planets and objects and spark the objects and things rather
than we're just living in a giant gas cloud. That's right. Yeah,
(04:50):
So that's the question we're gonna try to tackle today,
give you a solid answer for it. And so as
usual before we answer the question we I went out
and I asked bunch of unsuspecting you see, Irvine students,
off the top of their head. I asked them that question.
So think about it at home or wherever you're listening.
Why do you think there are stars and planets and
not just a smooth universe? Here's what people had to say.
(05:14):
Why is the universe so lumpy like? Why doesn't matter
just spread out totally smoothly and evenly through the universe.
I want to say gravity, because there's like a certain
kind of gravity putting things in place. And I have
no idea. Okay, gravity, it's a result of the big bank.
You had matter and antimatter, and they made clumps and
(05:36):
they kept expanding, and that's just how it occurred. At
least that's the model that I've heard. There were at
some point areas where there was a slight greater density,
and you know, in the matter in the universevity works,
a greater density will kind of collapse in the greater
and greater and greater density to you have a galaxy,
(05:57):
your plans or whatever the ions. Okay, all right, so
that's pretty interesting. I feel like you should maybe stop
advertising that they're U s Irvine students because I don't
know if you're helping the marketing there. I think it's
wonderful all these U see Irvine students are willing to
stop and think about a random question from a randy,
random scruffy looking dude and think about the universe. Likecent
(06:21):
of people answer these questions. To me, they get full
credit even just for trying, for thinking about it, for
engaging right. To me, that's wonderful. When we first started
this project, I was sure I was going to get
one percent answers. So the fact that they don't know
not a big deal. The fact that they try to answer,
that's wonderful. I think you should try it down the
streets of New York next and see what kind of
reaction you get get out of here. Yeah, well, as
(06:43):
you were suggesting, maybe I should go up to cal
Tech and see see if they get them more precise answers.
But everyone seems to say gravity as the answer to
the question. Yeah, everybody says gravity, And I think that
comes from everybody's feeling correctly that gravity plays a big role, right.
Gravity is the thing that made these structures. Gravity is
which responsible for holding a start together. Gravity controls the
(07:06):
shape of the galaxy. Gravity certainly plays a big role,
but I guess the twist is that it's not the
only thing you need to make stars. Right. Gravity only
clumps links together if you if you already have small
clumps to begin with, right, that's right, Gravity is not
the complete answer. If you had a universe that was
totally smooth, right, completely smooth, then gravity couldn't do anything
(07:30):
because each particle in the universe would be pulled both
left and right with equal force because it would be
equal amounts of stuff on both sides of it, And
so every object would be sort of like pinned down
by gravity. But it couldn't form any structures, right, So
gravity can't make lumps. It can only exaggerate lumps. Once
you've gotten a little bit started, we paint that picture
(07:52):
a little bit more for me. So let's imagine a
perfectly smooth universe, meaning that all the particles in the
universe are kind of at the same distance from each
other as every other particle in the universe exactly. So imagine,
you know, every particle is on a grid, right, and
they have one particle every centimeter or something. Right, So
take a perfectly exact grid. Everyone. Every particle is one
(08:15):
centimeter apart from the next particle exactly. And if you're
thinking this is strange and artificial, it's actually very simple, right,
And it's very natural. The opposite idea that there's one
place where there's particles are closer together, or they're denser
and they're denser, or something that's strange, that's unusual, that
would be like, well, why they're not here. So having
a perfectly smooth, symmetric universe as a as a starting
(08:38):
point actually makes the most sense. It's the most natural concept,
like a perfect jelly or like a perfect crystal exactly,
like a perfectly smooth chocolate pudding with new lumps in it. Right.
So if and and if the universe is infinite, you're
saying that cloud of perfectly ordered particles would not clump
(08:58):
together exactly. So take one random particle, right, And it
doesn't matter which one you choose, because we set this
up so that all the particles are exactly the same.
So pick one random particle. Now, that particle is going
to get pulled on by all the other particles in
the universe due to gravity and other forces. But let's
just think about gravity right now. Now, Um, there's an
infinite number of particles pulling it to the left, and
(09:20):
an infinite number of particles pulling it to the right,
and up and down to right exactly, and in any
any way you slice it, you get the same answer. Right. Um,
you divide the universe into two halves around this particle,
and one half of the universe is pulling it one way,
the other half is pulling it the other way. It
exactly balances out. It cancels perfectly. Right. It's like if
you have two kids and each one is pulling on
(09:41):
one arm, You're not going anywhere. Right. Does that happen
to you often? That's a random hypothetical I just invented.
It's not that I have two kids who often have
totally different ideas about what we should do or um,
where they want to go or where they want to eat.
That's right, um. And so in this scenario, every particle
is an equilibrium. Right. There's no way to begin lumpiness
(10:03):
because everything is being tugged equally left and right or
up and down, or you know, back and forth. So
you would the universe would just sit there, It would
just stay static. It would it wouldn't wouldn't move right, like,
we would just stay there forever, because every particle would
just be perfectly bounds where it is. Exactly. It's like
if you put a ball in the bottom of a bowl, right,
(10:25):
it's just gonna sit there. It's not gonna go anywhere, right,
And that's exactly the situation of each of those particles.
They're sitting in the bottom of a bowl. That bowl
is the gravitational well made by all the other particles
in the universe. And so if the universe is infinite,
then you can apply the same argument to every particle, right.
And so if you start out with an infinite, smooth universe,
(10:46):
then you can't get any structure. You can't start to
build anything. Hold on, you said that if that's only
if the universe is infinite, But what happens if we
have this perfect jelly and the universe is finite, meaning
that at some point ends. Yeah, well, then this argument
doesn't apply because there's some point um Because then this
argument only applies to the very center of the universe. Right. Then,
(11:08):
if the universe is finite, that means that it has
a center, right, that there's someplace where there's an equal
amount of stuff to the left and to the right
and up and down right, and this argument would only
apply right there, or if you go to the edge
of all that stuff right. This is again assuming the
universe is finite. If you go to the edge of
all that stuff, the argument doesn't hold anymore. You have
more stuff on one side than on the other. So
(11:31):
in the scenario of a finite universe, everything would be
attracted towards the center. Everything would be attracted towards the center.
All everyone, all the particles would just go towards the center.
And then what would happen? Man, I think it would
get like a huge star or a massive black hole,
or it would be a pretty crazy party, So the
universe would be just one star or one black hole.
(11:51):
I'm because I would be pretty complicated, but I think, yeah,
you would end up with one really big blob of matter, um,
and it would be you know, it wouldn't be compally
compressed into a point because matter resists being compressed and
and if it was spinning right then that keeps it
from being compressed further. Um. I don't know if anybody's
really studied what would happen if you just like had
a huge universized blob of finite matter and then let
(12:15):
it collapse. That would be fascinating. So it would be
kind of this one just one, not two, not three,
just one giant lump of stuff. That's right. And even
in that scenario where the universe is perfectly smooth but finite, right,
you can't get any asymmetries. Everything has to be perfectly
balanced in every direction. Right. Yes, you have a center,
(12:35):
so everything's attracted towards the center, but you can't like
make stars clumping along the way as they're getting dragged
towards the center. Still has to be perfectly smooth because
it's the same in every direction, right, In order to
get the kind of structure that we see when we
look at the night sky, you have like a star
here and no star there, and or galaxy here and
galaxy there. That's and those are asymmetry. So right, that's
(12:57):
a structure, that's a lump. Yeah, it's a in the
universe exactly. So that's obviously not the universe we're in.
We're not in a perfectly smooth, jelly universe, and we're
not living in one giant, singular super cluster of stuff.
We live in this kind of a stranger universe, right,
and thank god we do, right. I mean, it would
(13:17):
be pretty boring to live in an infinitely smooth pudding
or even just have like one big star living in
a perfect jelly. Seems pretty pretty peaceful to me. Again,
I think you should have a snack before we do
this podcast. Okay, although, as you tell you tend towards
these food analogies that I think it just reflects what
you're feeling rather than what you're thinking. Well, let's let's
(13:37):
get into how lumpy the universe is and how it
got that way. But first let's take a quick break.
All right, So we don't live in a perfectly smooth universe,
and we don't live in a universe such as one
(13:59):
giant cluster, black hole, slash star. That's not the universe
we'll live in, right, We are actually in a very
lumpy universe. Yeah, And the universe, the structure universe is
really fascinating. We should dig into it really deeply in
another podcast episode and talk about it and why it
is this way in that way. Um, but let's just
review briefly sort of where we are in the universe,
(14:20):
the the status of the lumps, the level of lumpiness
of the universe. Yeah, so we we are sitting here
on Earth presumably, that's right. We are two lumps on
a rock. Yeah. Um, presumably most of our listeners are
on Earth. And if you're not, by the way, if
you're listening to this podcast and you're not on Earth,
we really want to hear from you. Yeah. Absolutely, But
(14:40):
we are in a big rock around rock, going around
a sun, a star, and that's our solar system, right,
and even that is super lumpy. I mean from the
point of view of like how smooth this stuff distributed.
You know, people are probably familiar with how far away
the Sun is. It's you know, it takes a time
for light to even get there. It's minutes and minute,
it's in minutes, right, And the Sun itself is a
(15:02):
huge blov of matter, but it's super far away. You know.
The size of the Earth is enormous and the size
of the Sun is enormous, but the size of the
distance between them dwarfs both of them. Right, So even
just the solar system is really really lumpy in that
sense that the matter is concentrated and not spread out.
And then our solarcism is inside of a galaxy. Right,
(15:23):
and that's even lumpier from that point of view, right,
Like the distance between stars is huge compared to the
size of the stars. And it had some sort of structure, right,
Like the galaxy has spirals and it's kind of thicker
and more dense in the middle. Right, there's no structure
at that scale too. Yeah, the galaxy told me it
doesn't like when you talk about it's thickening waistline rhead.
(15:45):
But it's true. It sparkly. I'm talking about its sparkliness.
It's beautiful. It's beautiful, the milky way. Um, yeah, exactly.
We got all these stars, hundred billions of stars, but
they're not just a blob, right, They're not just distributed
evenly all THEO. For a long time people thought that's
what happened, But now we know that they're arranged in
this amazing swirl pattern right or the center of the galaxy.
(16:07):
And then we have these arms that come out and
because it's rotating, those arms sort of dragged behind it,
and uh, and you get this amazing swirl and then
you can keep going like the galaxy is part of
a supercluster of galaxies and that's super. No, you missed one?
What you missed one? The galaxy is part of a
cluster of galaxies, right, And when we talk about a cluster,
we mean things that are gravitationally bound to each other,
(16:29):
that essentially are orbiting each other over billions and billions
of years. So we and ours is called the local group,
right Like our cluster of galaxies is very imaginatively called
the local group. I know that sounds like a temporary
name somebody came up with, like, oh, I need to
call this something and talk to my advisor, and then
it just stuck and they're like, dang, and I should
have named it after my dog. What's the opposite of local?
(16:53):
Like basically, just here, it means the galaxies near us, right,
It's pretty lame name. Um yeah, so that's the cluster.
You know, our galaxy cluster is green and you know
local sources locally, that's right. I don't think it's vegan,
but at least it's local, right. Um yeah, exactly. Our
(17:22):
galaxy is part of a structure of of other with
other galaxies. Even that cluster is part of another structure
in the universe, right. Yeah. They call those superclusters, and
these are basically clusters of clusters another imaginative name. Huh.
And again you might ask, like, are these totally arbitrary?
Is just making this up? Could you have organized it differently?
(17:42):
The answers, No, there's some science behind it. We think
about how these groups operate, you know, And essentially a
supercluster is not just a really really big cluster, it's
a cluster of clusters, meaning that the each cluster inside
a supercluster is gravitationally bound to itself, and then those
things themselves are gravitationally bound to each other, and that's
(18:02):
what makes the super clustered. They're sort of trapped in
a sort of gravitational bubble almost. Yeah, the way like
you know, the Earth and the Moon are a gravitational system, right,
which is embedded inside the Solar System, which is embedded
inside the galaxy. Right, you might say it's arbitrary to
define whether or not the Moon is part of the
Earth system, of the Solar System, whatever. Really makes much
more sense to consider the Earth to be part of
(18:22):
our system, and then the Solar System may be part
of the galaxy, rather than just say like, oh, it's
all one big galaxy. So that's why we get these hierarchies,
and it's amazing that we have these hierarchies, you know,
and like also because you can zoom down right and
you get like down to the atom and things are
orbiting and stuff. So we have this over incredible the
different distances from microscopic to what megascopic we have similar
(18:45):
structures of things orbiting each other and right on these
on these large scales, like an infinite Russian doll, you
can stack them up almost infinitely, seems yeah, but infinite,
we don't know, right, We talked about that another time,
Like we think the universe probably has the smallest scale,
and when we talk about the structure of the galaxy
as the structure of the the universe, and another podcast episode
we'll talk about the biggest structures in the university is
(19:07):
a whole other fascinating topic. You can keep going in.
There are bigger, bigger structures, right. Well, there's a point
where they stop. Yeah, at some point they stop. At
some point they stop. There's an end to the Russian doll,
as far as we know, there is. There's the largest
Russian doll. Yeah. Um, anyway, but that's the topic for
another another day. Let's talk about why why we have structure. Yeah,
(19:28):
the point is that there is structure, right, Like, we're
not in a smooth universe and we're not just one
giant lump. There is like texture to the universe, right,
there's features, there's things to look at, there's good stuff
to see exactly, and as our you see I question
answers earlier said gravity is responsible for forming those things.
(19:49):
But gravity couldn't start those structures, right, That was the
point we were making earlier. So the point is that
gravity can't make lumps. When you start a lump, gravity
will accelerate like a chain reaction. Right, when you have
one point that's denser than everything else, it will have
a stronger gravitational pull and it'll start to attract stuff
and then look at heavier and have a stronger gravitational pull,
(20:09):
and it will feed on itself. But if everything is smooth,
then you can't. So the question is, so gravity can
make lumps bigger, but the question really comes down to
where did the first lumps come from. It's kind of
like gravity can roll a snowball down the hill, but
it can't sort of start the snowball rolling, Yeah, exactly, exactly,
Like once it's rolling, it gets bigger and lump here.
(20:30):
But you need some sort of something to get that
snowball going. Yeah, you have to knock it out of
equilibrium to get it to get things snowballing exactly. Okay,
all right, So how did the universe key head lumps?
How is it not perfectly smooth or one giant? So
(20:50):
that was a big mystery for a long time, right,
because it's very natural to think that the universe started symmetrically.
I think probably the most popular model for how the
universe started is the universe versus infinite and that has
infinite amount of matter in it, and that was created
in the first moments, right that we don't understand at all.
But not understanding it means we want to start with
the simplest idea. Okay, And it's not very simple to
(21:12):
imagine the creation of an infinite universe with an infinite
amount of stuff in it. But if you're gonna go there,
it makes more sense to say that the universe starts
out smooth. That's where this idea of smoothness comes right, right,
like simplicity, because the opposite like, oh, that the universe
was created with some initial lumpiness, that's weird. Because then
you have to ask why this lumpingness, Why not that lumpiness?
Who made that choice? Right? And uh so it was
(21:34):
a big puzzle for a long time. Um, And there's
really only one way that we know of that you
can make lumpiness out of smoothness. There's only one thing
in physics that's capable of doing that, Meaning there's only
one thing they can add features to something that should
be perfectly plain. That's right, what you need there's something
(21:55):
that's not deterministic, something which has a random element to it, right,
because if every particle universe starts in the same situation,
then they should all have the same future. Which you
need is to distinguish them somehow, for this one have
a different future than that one, for this one, have
a different experience somehow. The only thing we know they
can do that that can break determinism is quantum mechanics.
(22:15):
Because quantum mechanics has real randomness in it. Is that
the source then of randomness in the universe. Like without
quantum mechanics, we would all be perfectly smooth. Yeah, exactly,
But there was still another puzzle, right, So quantum mechanics
gives you randomness, but you know, quantum mechanics does not
something you notice. You don't like drive around and notice
random stuff happening from quantum mechannicals, Like if my phone
(22:38):
is here, it's not here and there, that's right. I mean,
maybe your bank accounts seems to fluctuate randomly, but there
actually is an explanation. My bank account could use more physics,
for sure. I am a quantum mechanic accountant, quantom accountant
um exactly. And that's why quantum mechanics took such a
long time to discover, because people thought the universe was deterministic.
(23:00):
I thought two particles in the same situation would always
have the same future. I see, there's no reason for
them to be different. Like if you create a universe
without quantum mechanics, there's no reason for all the particles
to be different. There's nothing that gives it that initial
randomness exactly. The problem is that quantum mechanics is a
tiny amount of randomness, right, it's at the particle scale.
(23:22):
It's super duper small, right, these tiny little fluctuations, And
what are we talking about concretely, we're talking about like
particles being created out of the vacuum. Quantum mechanics can
do that. It can take energy and just turn it
into particles and then they can turn back into energy.
Or you know, this particle can have a chance to
go left or right, and you know, maybe this one
goes left and another one goes right. This kind of stuff,
(23:43):
it's really really tiny effects, not really enough to get
gravity going because gravity is super duper weak, right, Gravity
needs more than the tiniest little discrepancy. I mean, if
you've given billions of years. But the kicker is that
the universe used to be small, right, that's the twist.
Ending is that the universe used to be really tiny
and small. That's right, And so the very first moments
(24:04):
of the universe were super dramatic. What happened in the
first first moments of the universe was inflation. Inflation is
this idea that the universe used to be much denser
and then it got stretched out, it got inflated, right,
And that's just not stuff moving through space. This is
the actual expansion of space itself, meaning things got stretched right,
more space was made everything I'm blown and inflated and
(24:27):
blown up. What that means is that the microscopic became macroscopic.
We'll step us through this. So you're saying, this is
all this all goes back to the Big Bang, right,
Everything goes back to the Big Bang in the end.
You can blame everything in the Big Bang technically, I
guess yeah, um officer, I was speeding because the Big
Bang dot dot dot dot dot. I blame the universe. YadA, YadA, YadA,
(24:51):
I was speeding quantum mechanics. That gets me out of
every ticket, trust me. Before we keep going, let's take
a short break. Yeah, so the universe used to be very,
(25:14):
very small, and that's where these that's where quantum mechanics
played a big role, right, Yeah, And be careful when
you say the universe used to be very small, because
we're still saying the universe was infinite, right, and an
infinite amount of stuff in it, but it was denser, right.
It used to be more squished when it was created,
and then it was and then all that stuff was
stretched out due to inflation. Oh. I see, So it's
(25:34):
like an infinite ruler getting stretched. It's still infinite, right,
I see. So you're saying that the features we've see
in the universe today are really just the quantum features
that we used to have when we were denser, not smaller.
But now when inflation happened at the Big Bang, everything
all these small fluctuations got way way bigger. Yeah, it's
(25:56):
like an ant man right where he can. He can
make things much much of it. Right, ants can be enormous,
and then they can do construction projects and you can
ride in the back of a butterfly and cool stuff.
Take the microscopic and make it macroscopic. Right, So the
timeline is the universe is created perfectly smooth, right, little
quantum fluctuations happen a little bit this, one particle moves
(26:19):
a little bit this way, one particle moves a little
bit that way. Then inflation takes over and blows that
up right and inflates. It makes those tiny little fluctuations
into bigger fluctuations enough to see gravity, and then gravity
takes over for the next fourteen billion years. YadA, YadA, YadA.
I was speeding officer. I'm telling you that story works
(26:43):
every time. Yeah, they probably fall asleep before you finish.
Another physics professor, you just let him go. So you're saying,
the universe used to be small or denser, and and
everything was smoother at that scale, except that if we
didn't have quantum mechanics, but we still had inflation. Then
(27:05):
we would have exploded the universe or expanded universe, and
it would remain smooth. Yes, exactly, it would remain smooth
because we had those quantum fluctuations that a little bit
of random this at the beginning gave the universe texture exactly.
And those little fluctuations were random, right, and they could
have been different, different random throws of the universe dice,
(27:26):
and we would have a completely different structure. I mean,
I think the kinds of structures we would have would
still be the same. We would still have galaxies and stars, whatever,
but they would be arranged differently. So you might ask,
why do we have a galaxy here and not there?
And you can trace the answer that all the way
back to one little particle fluctuating my millibil of seconds
after the Big Bang. If it fluctuated this way, we
(27:48):
get this galaxy. We fluctuated that way, we get a
different galaxy, or in the same galaxy in a different place.
That you said that that provided the seeds for the structure,
meaning it would have and it expanded, it would have
been smooth, but it had these kind of slightly small
shades of a texture, and those those shades became exaggerated
(28:09):
by gravity, and then things started to clump around those
little shades of texture exactly. And we can see this.
We can look back in time and we can see
this progression happening. Like if you look back deep, deep
into the history of the universe, you see the first
light that we can see, which comes from about three
eighty thousand years after the Big Bang. It's the cosmic
microwave background. We've talked about a few times. This light
(28:30):
is really really smooth. It's almost the same no matter
where you look at it. It's like the same color,
the same temperature, whatever. But if you measure it really
carefully that you can see little variations, tiny little fractions
of colder and hotter spots. Those that took four hundred
thousand years just to get that far right, those are
the seeds of from this quantum fluctuations exaggerated by gravity
(28:54):
for four hundred thousand years, then propagated forward in time.
Give gravity another few billion years, and you start to
get things like stars and galaxies and all that stuff. Right,
But we can see these quantum fluctuations from the early universe.
It's like the pattern that made our our cosmos was
totally random. It was totally random, exactly. And we think
quantum mechanics is truly random, right, not like there's some
(29:17):
hidden process that's controlling it that we don't understand. We
think it's really truly random. As mind blowing as it
is for anything in the universe to be honestly truly random,
it is, and it affects our universe is structure at
the deepest level. Right. Wow, it's amazing to think that
the reason you and I are here, or the whole
Earth this year, or the whole Sun and our solericism,
(29:37):
or even maybe even our galaxies here is just the
the random fluctuation of one little tiny particle way back
in the Big Bang. Yeah, it's the truth, man, The
truth is stranger than fiction. That's why. That's why I'm
a physicist, because you know, the universe will always alarm you.
The universe is like weirder and hotter and nastier and
crazier and stranger than anything human could or invent. Right, Well,
(30:01):
depends on how crazy and weird you are. But how
hot and where you are that's a whole different podcast.
So um, I'll have to play this podcast for my son,
But that basically answers this question, right, like why do
we have stars and not to the smooth distribution of matter,
(30:23):
you need two elements. You need quantum mechanics to give
you any fluctuation to avoid the smoothness, to break the
balance exactly, to break the balance, and then you need
inflation to blow it up so that it matters, and
that gravity can then take over. So it's a complicated
dance to Gravity takes these small fluctuations and basically exacerbates them, right,
it makes them, yeah, lumpier and clumpier than than it started. Yeah,
(30:48):
but remember gravity can only take little lumps and make
them into bigger lumps, right, It can't make lumps if
something is totally smooth. All right. Thanks to everyone for
listening to this lumpy episode and for listening to my
long explanation to my son's short question. Yeah, and whether
you're a movie star like Tom Cruise or just a
(31:09):
scruffy physicists, if you have any question or lumpy or
smooth or why or why do you have to be
a movie star or a scruffy physicist? Are you saying
you can't be both? That that no you can totally
be both. Totally. Yeah, don't ask me for a counterexample.
I can't think of one. Maybe maybe in another random
(31:29):
role of the universe. That's right. Why are you not
a movie star? Dad? Quantum mechanics, So whether you are
any of these things, if you have any questions, but
you can write us at feedback at Daniel and Jorge
dot com. We love getting your email, We love answering
questions on Twitter, so get in touch, send us your thoughts.
(31:51):
And so the next time you look out into the
night sky and you see all those sparkly stars, just
think everything is there. You are there because the one
and them part of them. But you still have to
pay your taxes and your speeding tickets unless you can
talk your way out of them. If you still have
(32:16):
a question after listening to all these explanations, please drop
us a line. We'd love to hear from you. You
can find us at Facebook, Twitter, and Instagram at Daniel
and Jorge That's one word, or email us at feedback
at Daniel and Orge dot com.