April 16, 2024 • 41 mins
Daniel and Jorge answer questions from listeners like you. Get your questions answered: questions@danielandjorge.com
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Speaker 1 (00:08):
Hey, Daniel, how long have we been doing this podcast?
Speaker 2 (00:10):
Now?
Speaker 3 (00:10):
Oh? Man, I'm not sure. Kind of feels like forever.
Speaker 1 (00:14):
Do you think we could go on forever?
Speaker 3 (00:15):
I don't know. I don't think we're going to run
out of topics.
Speaker 1 (00:18):
You think there's an infinite number of questions we can
talk about in physics.
Speaker 3 (00:23):
I think you could just keep asking why forever? Yeah?
Speaker 1 (00:26):
Why do you think that is?
Speaker 3 (00:28):
I think you just proved my point.
Speaker 1 (00:29):
Wait, what do you mean why? Q ed you pretended
to say just because I said so ardude.
Speaker 3 (00:37):
Because the universe says so. Universe is the ultimate?
Speaker 2 (00:41):
Dad or Mom?
Speaker 1 (00:57):
Hi, I'm orham Mack, cartoonists and the author of Oliver's Universe.
Speaker 3 (01:01):
Hi, I'm Daniel. I'm a particle physicist, a professor at
UC Irvine, and I think I'll always be asking why, why?
Speaker 4 (01:07):
What?
Speaker 3 (01:09):
Why this universe and not some other universe. Imagine some
moment in the deep future when we see the final
theory of the universe that describes the most fundamental basic bits.
I think people are still going to look at that
idea and wonder, why does it work this way? Why
couldn't it have been different?
Speaker 1 (01:27):
What if you get to the end Daniel, and you
figure it everything out, and the answer is just because.
Speaker 3 (01:35):
Is that really an answer?
Speaker 1 (01:36):
Though it is, I give it to my children all
the time.
Speaker 3 (01:40):
I don't know if that's an answer or a cop out.
It kind of means like there is no answer, you know.
One version of the answer is, Look, the universe could
have been lots of different ways. It just is this way,
which means there's fundamental randomness, not just in the operation
of the universe, but in the very laws that government.
Speaker 5 (01:56):
Right.
Speaker 1 (01:57):
But it's still an answer that wouldn't be satisfying. Ye,
going to sleep soundly that night, and just one night
after that, you'll be totally fine. I see how deed
your physics roots go.
Speaker 3 (02:08):
I'll have one long dark night of the physics soul.
Speaker 1 (02:11):
Yeah, and then you're over it. Yeah, that's fine.
Speaker 3 (02:15):
You've got to embrace stuff and move on. You know,
no point in holding grudges against the universe.
Speaker 1 (02:20):
Well, speaking of moving on, Welcome to our podcast, Daniel
and Jorge Explain the Universe, a production of iHeartRadio.
Speaker 3 (02:26):
In which we refuse to move on until we understand
something and explain it in an understandable way to you.
We think, we hope we pray that the universe is understandable,
is explainable, is digestible by our petty little human minds,
and we do our best to bring you up to
the forefront of human knowledge and the abyss of human ignorance.
Speaker 1 (02:45):
That's right, because there is still a lot that we
don't know about the universe, a lot to discover, a
lot to find out, a lot to explore. In fact,
maybe we should rename this podcast Daniel and Jorge wonder why,
although is that taken? Is that taken?
Speaker 3 (02:58):
It's a great name for a show, and somebody should
really do that.
Speaker 1 (03:01):
Yeah, somebody should make a yeah TV show maybe for kids.
Speaker 3 (03:04):
Yeah, exactly, Yeah, replace our names with some kids name
or something. I don't know, we'll figure it out.
Speaker 1 (03:08):
Yeah, an awesome girl's name. Perfect. I'm sure they'll give
us a show, even though we've never made one before.
Speaker 3 (03:16):
Now you're just being ridiculous.
Speaker 1 (03:18):
Yeah, who would do that?
Speaker 3 (03:19):
There are a lot of amazing mysteries in the universe
things to wonder about, not just whether two total nubes
can make a TV show on PBS, but questions about
the nature of the universe, how it works, why it
works this way not some other way. Unfortunately, we have
not yet run out of those questions.
Speaker 1 (03:35):
Yeah, it seems that human curiosity is sort of endless,
and we have evidence of that from all the questions
that the podcast receives from listeners.
Speaker 3 (03:43):
Because the process of doing science is tapping into those
human questions to wonder, why is it this way not
some other way? How does this idea fit with that
other idea? Can I click them both together in my head?
When they don't quite fit? That's an opportunity to learn something,
maybe to reveal something about the universe. That's how science
moves forward. People asking questions, and those people are podcasters, scientists,
(04:05):
television show producers, and everybody else who wants to understand
the universe.
Speaker 1 (04:09):
Yeah, we get lots of questions, and sometimes we actually
answer those questions here on the podcast, questions that we
feel everyone would enjoy thinking about and finding out what
the current answer and science is.
Speaker 3 (04:21):
That's right. But even if your question doesn't make it
to the podcast, you will still get an answer. I
will write back to you and try to help you understand.
So please, everybody, don't be shy write to us to
questions at Daniel and Jorge dot com. We really will
right back.
Speaker 1 (04:36):
So to the end the podcast, we'll be tackling listener
questions Number fifty three Daniel Hoffen. Do we do these now?
About every month we answer listener questions.
Speaker 3 (04:49):
We used to do it about every month, but we've
been getting a lot more questions recently, so I've uped
it to almost every week to try to catch up.
Speaker 1 (04:55):
Wow, what do you think is causing this increase in questions?
Speaker 3 (05:00):
Good question, I'll add it to the list.
Speaker 1 (05:02):
We'll spend an episode talking about why we get more
questions in the episode, and then we'll implode. We'll implode
from the paradoxical nature of this.
Speaker 3 (05:10):
The infinite recursion in that question will generate information density
that creates a black hole podcast.
Speaker 1 (05:15):
Yeah, and then we'll be able to go on forever.
Speaker 3 (05:19):
That's called the singularity.
Speaker 1 (05:20):
Because then the next episode will be yes, how are
we doing a podcast while we're getting questions?
Speaker 3 (05:26):
I can just see it alien anthropologists in the future
trying to figure out how human civilization ended in a
podcast singularity.
Speaker 1 (05:33):
Well, hopefully we're not the end of civilization, but maybe
the beginning of a lot of people's questioning about the universe.
And so we have three awesome questions here today that
we're going to try to answer or at least talk
about great questions about the strong force, about the creation
of matter, and about the infinity of time. Hopefully this
podcast will not be an infinite length of time, but
(05:56):
we hope your love for it is infinite no matter
what kind of matter we talked about.
Speaker 3 (06:01):
I hope anti matter doesn't lead the anti love.
Speaker 1 (06:03):
Yeah, that would be a strong statement. All right, let's
dig into our first question, and this one is from Emily.
Speaker 3 (06:09):
We actually have two questions here from Emily and from
Sarah that asked related questions. I thought we could answer
all together a double question.
Speaker 4 (06:17):
All right, Hi, Daniel and Joje. Here's Emily and I
have a few questions about the strong force. First, how
does the strong force even really work? And how can
it be that it gets stronger with the distance? Does
that ever end? As in, is there a maximum strength
(06:39):
to the strong force? Because it cannot get infinitely strong?
Speaker 3 (06:45):
Right?
Speaker 4 (06:46):
If it did, we could never break apart of proton,
could we? And one more question, If I had the
strength to pull two quarks.
Speaker 6 (06:58):
Away from each other, would I at some point need
infinite strength to keep pulling? Thanks for answering my question.
I really like your podcast. Keep up the great work.
Speaker 7 (07:12):
Hi.
Speaker 8 (07:13):
I want to ask about the strong force. What is
the strong force? What does it do? Why is it
so strong? Why is it so difficult to understand and calculate?
And why is it range considered shorter than electromagnetisms.
Speaker 1 (07:34):
All right, some pretty strong questions here, Daniel. Do you
think we're strong enough to answer it?
Speaker 3 (07:39):
I hope. So the strong force is tricky. It is
complicated stuff, and these are great questions trying to get
intuitive understanding of how it all works.
Speaker 1 (07:48):
I like how she phrased the question Emily here, how
does that even work?
Speaker 3 (07:54):
How does it all even work? Can we just describe it?
How can we actually explain it?
Speaker 1 (07:59):
All? Right? Well, we had two questions that we'll tackle
one at a time. Daniel, How does the strong force work?
And why does it get stronger with distance?
Speaker 4 (08:07):
So?
Speaker 3 (08:08):
The strong force is a force between any particles that
have color charge. Color charges is like a version of
electric charge. You know how electrons have negative charge and
protons have positive charge, and that's how you know they
attract each other or to electrons will repel each other.
In a strong force, we have a different kind of
charge we call it color, and any particles that have
(08:29):
these color we say feel the strong force. This is
just kind of descriptive the way we gave labels too
particles to describe their charge, to explain the forces we
see pulling and pushing between them. We give these colored
labels to quarks to describe the forces that we describe
between them.
Speaker 1 (08:46):
Well, maybe taking a step back, the strong force is
one of the four fundamental forces that businesses have noticed
about the universe, and these are the forces that pull
and push matter together or apart.
Speaker 3 (08:57):
That's right. It depends a little bit how you count
the forces. Some people say two, some people say three,
some people say four. And the four force version you
have gravity, which is not really a force, and then
you have electricity and magnetism as one force, the third force,
and then the strong forces the fourth and the more
simplified version, we say gravity is not a force, you
don't count it. Electricity and magnetism have been combined with
(09:20):
the weak force into the electro weak force, and then
the second force is the strong force. So in the
sort of unified version, you really only have two forces,
electroweak and the strong force.
Speaker 1 (09:31):
And so the strong force is the one that pushes
and pulls quarks, right.
Speaker 3 (09:36):
Yeah, that's right. Anything with a color charge, which means
quarks and also gluons, electrons and muons, and those particles
don't have a color charge, so they just don't feel
a strong force the way a neutral particle doesn't feel
an electric field.
Speaker 1 (09:49):
Okay, and so part of the Emily's question is how
does it get stronger with distance? So does it get
stronger with distance? Meaning if you pull the quarts apart,
they're actually going to be pulling the dwarf each other
or apart more.
Speaker 3 (10:02):
Yeah, it's really weird and very counterintuitive with gravity and
with electromagnetism. If it's attracting two particles and you try
to pull them apart, it gets easier as you get
further apart. Imagine a proton an electron and you're holding
onto them with tweezers and you're pulling them apart. As
you succeed in pulling them further and further apart, the
force on them gets weaker and it gets easier and easier.
(10:22):
But with a strong force, we notice something different. We
notice that after a certain distance, the force stays constant,
doesn't actually grow with distance. It stays constant. So after
about like the width of a proton, if you pull
two quarks apart, the force on them is the same
no matter how far apart you pull them.
Speaker 1 (10:39):
Wait, what so it doesn't get stronger with distance only
for a little bit.
Speaker 3 (10:43):
It decreases with distance until you get about a proton's
width apart, and then it stays constant. It doesn't fall
off like one of our are square, the way electromagnetism does.
Speaker 1 (10:53):
Oh so the strong word doesn't get stronger with distance.
Speaker 3 (10:56):
Doesn't get stronger with distance in the sense that the
force doesn't increase, but the amount of energy stored in
that bond does because forces like the slope of the energy,
and so the energy is actually just growing and growing
as those two quarks pull apart.
Speaker 1 (11:10):
But the ford doesn't get stronger, right, doesn't get stronger.
There's just more potential the more you pull them apart.
You just like maybe you have more gravitational potential the
higher you go up a ladder.
Speaker 3 (11:21):
Yeah, exactly, And this feels weird compared to like electromagnetism,
but it's not so unintuitive.
Speaker 4 (11:26):
You know.
Speaker 3 (11:26):
You take a rubber band, for example, and you pull
on it. The force doesn't drop as the rubber band
gets stretchier and stretchier. Right, So there are some kinds
of analogies we have in the everyday world. But Emily's
probably wondering, like, why does this happen? How does it
work this way? And that's not something we really understand.
This is just our description of what we see happen
between particles.
Speaker 1 (11:46):
Part of our question is is there a maximum to
the strong for it? I guess she was imagining that
the strong force was like a rubber band. The more
you pull it apart, the stronger it gets. And so
she's wondering, is there a maximum to this force? Can
it just be infinite if you pull the two things
apart infinitely? But it sounds like you're saying that this
wouldn't really happen.
Speaker 3 (12:06):
It wouldn't really happen because the energy can't grow to infinity. Like,
as you pull these things apart, the four states constant,
but the energy stored in that bond just grows and
grows and grows and grows. But at some point there's
so much energy in that bond that the universe prefers
to transfer that energy into mass, to convert that energy
into quarks because quarks are actually pretty light. They don't
(12:26):
take a lot of energy to make. So the universe,
which prefers to spread energy out rather than have it
concentrated in one bond or in one state, will prefer
to create a bunch of quarks out of that energy.
So you have these two quarks that you're pulling apart.
The universe prefers to create more quarks to shorten the
distances between quarks, spending that energy to create the mass
(12:46):
and reducing the energy of the bonds.
Speaker 1 (12:48):
Well, what so I take two quarks they're held together
by the strong force, I pull them apart, and at
some point, like what kind of distance that we're talking about,
like a meter.
Speaker 3 (12:58):
We're talking about like the width of a proton.
Speaker 1 (13:00):
Oh okay, so a little smaller you pull them apart
the width of a proton, and then what like new
quarks pop up in the middle. You'd have to pop
up two new ones, right, One of the two new
ones is going to be attached to one of my
original protons, and the other new one is going to
be attached to the second of my original quarks.
Speaker 3 (13:18):
Yeah, exactly, And we do this all the time at
the Large Hadron Collider we create a quark and antiquark
pair with a lot of energy, so they're flying apart
super duper fast, almost at the speed of light, and
very quickly. What happens between them is you create another
quark antiquark pair. So instead of having a quark anti
quark a certain distance apart, now both of those have
a new partner to be bound with at half the distance,
(13:41):
and then those start to fly apart and that band snaps.
So you get this whole shower of quarks and anti
quarks being created. All that energy is converted into a
whole stream of new particles, and they like to stay
close together to minimize the energy stored in those bonds.
Speaker 2 (13:55):
Hmmm.
Speaker 1 (13:56):
Interesting, all right, so then you couldn't get to infinity
at some point. It's like the rubberband breaks, yeah kind of, yeah, exactly.
Speaker 3 (14:03):
It's like the rubber band prefers to snap rather than
to stretch out to infinity. And so in principle, you
could have a universe where two quarks are infinitely far apart,
holding infinite energy, but in practice the universe prefers to
spread that energy out. It's basically just entropy that very
unlikely to happen. The universe prefers configurations with more probability,
which means the energy is more spread out, and so
(14:25):
it replaced that infinite energy bond with a lower energy
bond and a bunch of quarks.
Speaker 1 (14:31):
So I guess the strong force is not that strong.
It snaps at some point.
Speaker 3 (14:36):
It's so strong and energetic that it usually breaks down.
Speaker 1 (14:39):
Yeah, all right, then, now Sarah's question our second question
of this question. See you're the one introducing recursion here.
We have two questions inside of one question. Sarah's question
is why is the strong for so strong? Now? Is
there actually an answer to that?
Speaker 3 (14:54):
There's not a great answer to that. There's a terrible
answer and a less terrible answer. Totally terrible answer is
this is just what we measure. We go out in
the universe. We measure the force between particles. We can
measure the strength of stuff. We can say, for example,
gravity is much weaker than electromagnetism, because if you take
two particles, you mostly feel electromagnetism between them rather than gravity.
(15:15):
Gravity is so much weaker. In the same way, we
can compare the strength of electromagnetism to the strong force
and say, hey, between two quarks which have both kinds
of charge, which force is dominating the interaction. So those
are just measurements we make out in the universe, just
numbers the way we measure like the speed of light
or planks constant. These are just things we see in
the universe.
Speaker 1 (15:36):
So basically, you're saying because you said so, because that's.
Speaker 3 (15:39):
What the universe is showing us. The slightly less terrible
answer is that we think at an earlier moment in
the universe, all the forces had the same strength. We
talked about this recently on the podcast. A lot of
these forces, their strength depends on energy, like how fast
particles are going, how much energy they have, the forces
get stronger or depending on the energy and the energy
(16:02):
density of the universe varies with time, like it used
to be hotter and more energy dense in the early universe.
So we think in the early universe, if you sort
of rewind the clock, a lot of these forces might
have had the same strength. So it might be that
very early in the universe the strong force and the
electroweak force were both the same strength, and then something
happened when the universe cooled, it like cracked in an
(16:24):
asymmetric way to give one of them more strength and
one of them less strength.
Speaker 1 (16:29):
WHOA, So there was like an option the universe had.
Is that what you're saying, Like it could have been
a different way, but somehow it broke that way, or
it could it have only broken this way?
Speaker 3 (16:38):
Yeah, we don't understand that. This is something in physics
we call spontaneous symmetry breaking, when the universe had a symmetry,
a balance, and then it cracked as it cooled. A
famous analogy for this is like you sit down at
a dinner table and you have silverware to your left
and silverware to your right. Which one do you pick? Well,
if you pick to your left, then everybody's going to
have to pick to their left. If you pick to
your right, everybody's gonna have to pick to your right.
(17:00):
And another example of this is the Higgs boson. As
the universe cools, all the particles started out having no mass,
but then the Higgs field gives mass to particles, but
not in a symmetric way. It made like the W
and the Z very massive and left the photon massless.
This is called electroweak symmetry breaking. So as the universe
cools and enters another phase, some of these symmetries crack
(17:22):
in a way we don't fully understand.
Speaker 1 (17:24):
So then are you saying that at different universe where
the strong force wasn't a strong that's a totally plausible,
mathematically possible universe that we could have been living in.
But somehow we're living in this universe where the strong
force is strong.
Speaker 3 (17:37):
It might be that those universes are equally possible, or
it might be that there's a reason that it cracked
this way and not some other way. It's not something
that we currently understand, so it's possible, But it might
be that we discover that there is a reason why
the strong force cracked this way and the weak forces
cracked the other way. Are currently we don't know why
it's so strong?
Speaker 1 (17:55):
Do you think it was random?
Speaker 3 (17:57):
There's so many different theories, some that control it, some
that even random. The true description of the universe is
probably something we haven't even thought of yet, so it's
still a deep question.
Speaker 1 (18:07):
I think the real question is if the strong force
hadn't been so strong, would you just still have called
it the strong force?
Speaker 3 (18:14):
We probably would have named it terribly. That's for sure.
Speaker 1 (18:17):
It could have been strong force.
Speaker 3 (18:20):
We have a pretty weak game in naming things. That's
what's constantly across the multiverse. It a strong bias here
because the strong force is so strong, it makes it
really difficult to use. To another part of Sarah's question,
why is it so difficult to do these calculations? And
the reason is its strength. It's hard to do calculations
with a force that likes to pop off all the time.
(18:41):
It's crazy reactive because it makes it much more sensitive
to getting the details wrong. Get a little detailed wrong,
it propagates to a much bigger mistake. That's not true
for the weak force, where mostly things just fade out anyway.
So you make a little mistake, it's going to fade
away and not affect your calculations. The strong force is
like recursive, It builds on itself, and so little mistakes
become bigger mistakes.
Speaker 1 (19:02):
M Terry volatile huh, yes, exactly. All right. Well, so
then to answer Sarah's question, it's either because if we
said so, or we don't know.
Speaker 3 (19:12):
Either there's no answer or there's an answer we haven't
found yet.
Speaker 1 (19:15):
That basically covers every possibility because just because.
Speaker 3 (19:21):
Keep digging, Sarah, keep digging.
Speaker 1 (19:22):
All right, Well, thank you, Emily and Sarah for those
great questions. Now let's dig into our second question, and
this one is about the creation of matter, So let's
dig into that. But first let's take a quick break.
(19:47):
All right, we're answering listener questions here, and our second
question comes from Trevor.
Speaker 5 (19:52):
Hey, guys, this is Trevor from Pittsburgh, Pennsylvania. I appreciate
you taking my question. I've been thinking lately about the
origin of the matter that we come across in everyday
life that just makes us up and makes up all
of our stuff, right, and how most of it probably
came from stars that fuse hydrogen into heavier elements naturally.
(20:13):
My presumption when I was thinking about this was that
most of the particles that make all this stuff around
us up probably spent some or possibly even most of
their existence as parts of hydrogen atoms before those atoms
were fused into heavier elements. But the more I think
about it, the less confident I am in this presumption.
Do we actually know anything about how much of the
(20:35):
normal matter that exists today has at some point been
a part of a hydrogen atom, And if there is
matter that has never been a part of a hydrogen atom.
Why not? And where is it? I think this whole
line of questioning brings up yet another question. Does it
even make sense to think of quantum particles as having
a long history like this or are they more kind
(20:57):
of ephemeral in nature. I really look forward to hearing
what you guys have to say on this. Thanks again.
Speaker 1 (21:02):
Well, it seems like Trevor here is asking about the
origin of matter, and the part I didn't understand is
exactly whether it could have been part of the hydrogen atom.
What does that mean?
Speaker 3 (21:11):
I think he's asking whether all the heavier bits of
stuff that are out there, iron and lithium and uranium
was once hydrogen. Like is it possible that uranium was
just made from nothing? Or was every atom made from
hydrogen atoms fused together? Is the history of every single
atom that it was once hydrogen I see?
Speaker 1 (21:31):
Or do we have some like original atoms out there
that were made heavy from the very beginning of the universe?
Speaker 6 (21:37):
Yeah?
Speaker 3 (21:38):
Exactly, Like is there any primordial uranium in the universe
that was never hydrogen? Whereas hydrogen the only path to
becoming an atom?
Speaker 1 (21:46):
Right, And we actually talked about this in our last recording.
Speaker 3 (21:48):
Did we Yeah, we talked about this in the Origin
of Matter a few times. It's a really fascinating concept.
It's incredible to me that we understand so much about
the early universe that we can talk about how madam
was and how it was fused, like down to the
seconds and microseconds.
Speaker 1 (22:03):
Well, I guess maybe there's two questions here. Is one,
can you make heavier matter instantly just from like the
basic building blocks of the universe without going through the
hydrogen atom? And the second question is what actually happened
in the Big Bang? Did something like that happen or
did all the matter in the universe go through hydrogen? First?
Speaker 3 (22:22):
Yeah, so let's trace the sort of early history of
the universe to answer this question. You start out like,
before there were any particles, you know, what was in
the universe. Well, the furthest back we can go is
to say there was some very hot dense state. We
don't know where it came from, we don't know how
it was made, we don't know what came before that.
Just start with the assumption you have some hot dense state,
(22:43):
and everything expands. That hot dense state becomes less hot
and less dense, so it becomes colder and more dilute.
So you have all this energy in these frothy quantum fields.
As it cools down, you can start to talk about
particles emerging from these fields the way like a room
that's flooded is just filled with water, and then as
you drain it, you end up with like droplets on
(23:04):
the floor. So now the universe is sort of filled
with the most fundamental particles quarks and electrons and stuff
like that.
Speaker 1 (23:11):
Before it was just pure energy like this is before
there were even quantum fields. Like the universe was so
nuts so that you couldn't stand being there.
Speaker 3 (23:19):
We don't know what comes before fields. The nutso state
of the universe is not something we can even describe.
There's some vague theories about it, you know, inflotons decaying
into quantum fields, but it's all very speculative. In question markye,
the first moment we can describe is the universe filled
with quantum fields. But those fields are so washed with
energy that it doesn't make sense to talk about particles
(23:39):
yet in those fields. It's only as those fields calm
down and cool that it makes sense to talk about particles.
As ripples in those fields, and.
Speaker 1 (23:47):
They calm down, cool because they were getting stretched.
Speaker 3 (23:50):
Out, right, Yeah, because as the universe expands, there's the
same amount of matter in it, so that matter gets
more dilute, right, and so you end up with particles
rather than just huge piles of enery.
Speaker 6 (24:00):
Right.
Speaker 1 (24:00):
But those first particles are not atoms. They're the building
blocks of atoms, meaning quarks. Right, So before you even
had an atom, you had a whole bunch of quartz
floating rep.
Speaker 3 (24:09):
Yeah, not just quarks. You have quarks, and you have gluons,
you have photons, you probably have dark matter, you have electrons.
You have all the sort of basic building blocks. And
we don't know that these actually are the most basic
building blocks. Just our current theory could be that quarks
are made of something else, quigglyons, and the squiglyons were
made first. But in our current description you end up
with quarks and gluons and photons and dark matter. No
(24:32):
atoms yet. Absolutely, it's still too hot for atoms to
even form.
Speaker 1 (24:36):
Right, So we had the basic particles quarks, gluons, and
then eventually those quarks fuse together to form protons and
neutrons exactly.
Speaker 3 (24:44):
The strong force is pulling on all those quarks. There's
a huge amount of energy. But then as things cool,
the strong force pulls those quarks together to make protons
and neutrons and other kind of bound states of quarks.
Here's a strong force at play pulling those quarks together.
Doublets of quarks like quark antiquark pair, we'll give you pions.
Triplets of quarks will give you protons and neutrons. That's
(25:07):
the moment when you go from like free particles to
bound particles, when the universe gets cold enough to bind
those quarks together.
Speaker 1 (25:14):
Right, right, Well, assuming that quarks and gluons and photons
are fundamental particles, right, isn't it, there are still the
possibility made they're made out of smaller particles.
Speaker 3 (25:23):
Yeah, exactly. If they're all made out of squiglyons, then
first you start with the squigglyons, which then coalesce into
the quarks and gluons, et cetera.
Speaker 1 (25:30):
Is that the official name squigglions?
Speaker 3 (25:33):
What's the macaltons, the wacinions? You know, who knows who
knows ons?
Speaker 1 (25:39):
Just to be clear, that's not the official name, right,
she made that up.
Speaker 3 (25:42):
I'm not aware of any theory of squig lyons. I
just made that up. Yeah, did it sound official?
Speaker 1 (25:47):
If it's every thing, I think you should get credit
for it.
Speaker 3 (25:50):
Oh yeah, you like that name, squiglyons. You think we
should be teaching generations as students about it.
Speaker 1 (25:55):
I think it's as good as quarks and gluons.
Speaker 3 (25:59):
You know, there's a big fight about the name of quarks.
There was one guy I wanted to call them quarks
and somebody else wanted to call them aces and the
quarksky one Mmmm. Yes, yes, I.
Speaker 1 (26:07):
Think we covered this in depth already, all the quarks
of it.
Speaker 3 (26:11):
But that moment when quarks come together into protons and
neutrons already have hydrogen. Essentially, the proton is a hydrogen nucleus,
so physicists consider a proton.
Speaker 1 (26:21):
Hydrogen even though it doesn't have an electron to make
it a whole atom.
Speaker 3 (26:25):
Yeah, we distinguish between the hydrogen ion just the proton,
and the neutral hydrogen atom, which is a proton and electron.
Speaker 1 (26:33):
So wait, are you saying that a proton is an atom?
So why do we even have the word proton?
Speaker 3 (26:38):
Why do we even have the word proton? Well, who's
the one getting philosophical there?
Speaker 2 (26:41):
Man?
Speaker 3 (26:41):
Why don't we even think about protons. We use protons
to count which atoms are which right, Helium has two,
lithium has three, et cetera, et cetera. So it's definitely
a thing in the universe we want to identify. But
when you have only one of them, we consider that hydrogen.
Even if you don't like that explanation, you think like,
protons are not hydrogen yet, then those protons do something
funky well before they find their electrons. In those first
(27:05):
few moments, there is still enough energy for those protons
to come together and make heavier elements like helium. So
in the first few moments after the Big Bang, you
make protons, you make neutrons, and then you also squeeze
those protons together to make helium. So then the question
is that helium did it once used to be hydrogen?
That's essentially what Trevor is asking. If you made primordial
(27:26):
helium right then during the Big Bang fusion, do you
still count that as having been hydrogen? I say yes,
because you didn't make the helium directly. You didn't make
like a proton proton pair directly out of quarks. You
made the protons first and then you fuse them together.
Speaker 1 (27:41):
Aren't you assuming a certain order, like that helium was
made out of two protons. But could like you know,
six quarks have come together to instantly make a helium
atom without ever being two protons in the middle.
Speaker 3 (27:56):
Yeah, great question. The standard story is that you start
with protons and neutrons. Neutrons are crucial here because onder
a few stuff together. You need the neutrons to be
like a buffer between the protons. You can't just fuse
two protons together to make helium. You end up making
like helium three in helium four because you need those
neutrons to keep those protons from being so close together.
Speaker 1 (28:16):
But it's still helium, isn't it.
Speaker 3 (28:18):
It's still helium because you only have two protons. I'm saying.
You don't just make two protons together. You also need
those neutrons. So in order for the scenario where you
make helium from nothing, you also have to make those
neutrons at the same time. But it is possible, Like
I think it's unlikely. I think it's much more likely
for protons and neutrons to be made first and then
come together to make helium. But technically it's not impossible.
(28:42):
You have this big soup of quarks and gluons, and
as it's cooling, it is possible for an entire helium
atom to coalesce out of that soup without ever having
been hydrogen.
Speaker 1 (28:53):
M And you can keep going right, like, maybe some
carbon also was created spontaneously. Maybe even some uranium was
created spontaneously in the Big Bang. Is that possible.
Speaker 3 (29:04):
It's possible. Now, uranium is unstable, so if you did
make primordial uranium, it would have decayed, but you could
have made like primordial lead, which is the heaviest stable element.
Now we're talking about really really tiny possibilities. And the
only reason we can't say it's totally impossible is because
if the universe is really vast or even infinite, then
anything that's super unlikely is gonna happen. And we want
(29:25):
to give Trevor as accurate an answer as possible. And
so it could be that there is an atom out
there made of lead which was created during the Big
Bang without ever having been hydrogen. But the overwhelming majority
of stuff in the universe that's made of atoms almost
certainly was hydrogen.
Speaker 4 (29:44):
First.
Speaker 1 (29:45):
The way you're saying there could have been one lead atom,
but only one, like given the observable universe, but the
universe that we can see. Do you actually have a
number for your estimated probability of this happening or are
you just kind of making it up in your head
right now.
Speaker 3 (29:58):
No, I'm just saying it's possible that the is one.
I mean, the probability of forming even helium directly out
of those quarks is so astronomical I think I would
bet against there being one in the observable universe. So
now if you're going for a lead, yeah, I'm not
going to take that bet either, but it is possible,
so you can't rule it out.
Speaker 1 (30:16):
We are talking about the astronomical probabilities, all right, So
then the answer is Daniel Wooden bet one. But it
is still possible to create matter that was not hydrogen first.
Speaker 3 (30:27):
Yeah, exactly. And Trevor also asked this follow up question
about like the nature of quantum particles. Can you think
about them having a long history or this sort of
a femarole, And this is a good philosophical question, you know,
you could ask like when is a photon the same photon?
If the photon bounces off of a wall, is it
the same photon or was it absorbed and recreated, and
(30:48):
that in the end is a philosophical question and sort
of an arbitrary distinction. You know, the information in the
universe flows through these particles and is preserved in those
quantum states, whether you count it as the same particle
or not. It's sort of like the question of whether
the Star Trek transporter actually kills you and recreates you
or transports you literally to another location. It's really more
(31:09):
of a philosophical question than a physical one.
Speaker 1 (31:11):
I see, Trevor, I hate another question here in this question.
He tried also to go recursive. Now is it still
a question, Daniel? If it has two questions inside of it.
Speaker 3 (31:21):
That's a good question.
Speaker 1 (31:23):
Yeah, let's keep going. Now why is it a good question?
All right? Well, Trevor, I think that answers your question.
Thanks so much for sending that in. And now let's
get to our third question, which is about the infinity
of time time time. So let's dig into that. But
first let's take another quick break. Or we're answering listening
(31:56):
to questions here today, and our third question comes from
I'll be.
Speaker 7 (32:00):
Hi, Daniel and Jorge. In any finite period of time
being constrained by the laws of physics, finite extents in
time or in space could never become infinite at least,
I think, how does physics, then, given the proposed finite
age of the universe, contend with the real possibility of
(32:24):
an infinite universe? Would it have had to have been
born infinite? If indeed it can't grow from finite to
infinite size, and working backward from a finite or infinite size,
how could that have grown from a universe that was
infinitesmally small?
Speaker 1 (32:44):
Thank you all right? I feel like this question is
also recursive in or at least it's giving me a
bit of a headache here talking about the different infinities.
I think what Abbi's asking is, do you need infinite
time to make an infinite universe?
Speaker 3 (33:00):
Exactly? And I think obvious Struggling to reconcile two ideas
that are out there in the sort of popular science universe.
One is that the universe might be infinite, could go
on forever and ever and ever, even beyond what we
can see, So the full universe, beyond the observable universe
could be infinite in extent. That's one idea, And the
(33:21):
other is this conception of the Big Bang as the
universe having started from a point that there was a
tiny dot of stuff and everything flew out from that dot.
That dot seems finite, and so I think Abby's wondering, well,
how do you start with this finite dot then end
up with infinite space filled with infinite stuff? That seems
like a disconnect.
Speaker 1 (33:41):
Right, right, because I guess the way the Big Bang
is usually percented, it does start with a dot, and
a dot seems finite.
Speaker 3 (33:48):
Exactly, and there's a way to interpret that. It's being
technically correct, but I think mostly it's misleading. People think
of the Big Bang as this tiny dot, like smaller
than an atom, containing all the matter in the universe,
which then expands ended out into empty space, and people
wonder like, well, how could that turn into something infinite?
And the way that we actually think about the Big
Bang is not in that sense at all. We think
(34:09):
about it more in the way that we just described,
And answer the last question. You start with potentially infinite
space already filled with stuff, but there was no empty
space back in the beginning, that everything was already filled.
However much space there was, it was already filled with
some hot, dense state, a state we can't explain. We
don't understand where it came from. But the Big Bang
(34:30):
describes the expansion of the universe from that point. So
there's no empty space. Everything's already filled, and the Big
Bang is not the explosion of stuff through that empty space,
but the expansion of that space, which makes it colder
and more dilute.
Speaker 6 (34:44):
Right.
Speaker 1 (34:44):
I think what you're trying to say is that, like
we think of the Big Bang as a moment of creation,
but you're saying that the Big Bang is not really
when the universe was created. It's just when the universe
expanded from being super compressed to being less compressed. The
universe was there already and it was infinite.
Speaker 3 (35:02):
Yeah, exactly. And that's because we know there's a limitation
to our theories. Like we can talk about quantum fields
and all that stuff describing space, and that works up
to a point, up to a certain density of the universe,
beyond which our theories break down. It's at that point
when everything is so dense that you can't really ignore
gravity anymore. You need a theory of quantum gravity to
describe the universe that is that dense. So before that,
(35:25):
we don't even try to explain. So we start our
history of the universe the first moment that we think
our theories can describe, when the universe is super hot
and super dense, but we think we can describe it
used in quantum field theory. Before that, we have no idea,
question mark, question mark, inflation, instantans, who knows, squiggly ons, whatever.
But the history of the universe begins in the first
(35:45):
moment we can describe, and the big Bang is the
evolution of that universe, the expansion, the cooling and coalescing
into particles, et cetera, et cetera.
Speaker 1 (35:54):
I think maybe what Auby is also trying to kind
of grapple in their heads, is this idea of find
time right, because a lot of physicists say that time
started with the big Dang, possibly, and that there was
no time before. If you sort of run the clock backwards,
at some point, there was no time, and so what
was the universe back then exactly?
Speaker 3 (36:15):
And that's extrapolating past that super dense point using just
general relativity, saying well, what if general relativity is correct
and that's the way time and space works, and we
can ignore the unignorable quantum effects. That's what general relativity predicts.
Predicts that time begins in the singularity of density. But
that's sort of ridiculous extrapolation. We know that quantum theory
(36:36):
needs to be accounted for there. So yeah, if you
extrapolate general relativity beyond where we think it's relevant, then
you get this prediction that time begins at some certain point,
which is also difficult to grapple with. But that's not
something we're confident doing because we know the theory breaks down.
Speaker 1 (36:51):
I see. So the answer is we don't know.
Speaker 3 (36:54):
The answer is we don't know, and we think it's
possible that the universe began infinite, that that first moment,
at least that we can describe the universe was already infinite,
filled with an infinite amount of stuff that then expanded
and cooled into a universe that was larger. Right, you
can take an infinite universe and make it larger just
by stretching it, so you can create new space everywhere
(37:16):
in that universe, making it effectively larger and colder. So
that's how we get to an infinite universe today, is
that you start with an infinite universe. Abby's totally correct
that if you start with a finite sized universe, you
can't then have an infinite universe. Today, we don't know
if the universe is infinite. We can only see a
certain distance out there. We know the universe is huge
and vast. It might be infinite beyond that horizon, or
(37:39):
it might be that it's finite.
Speaker 1 (37:41):
Well, I think maybe Abby is also maybe posing the
question like what happens if you take an infinite universe
and you squish it down to an infinitely small size.
Does it become then a finite universe? Because as we
all remember from Calculus one, if you divide infinity by infinity,
it depends, But one of the positive abilities is that
you get a finite number.
Speaker 3 (38:02):
You get a finite number in the limit, right, which
would take technically an infinite amount of time. The only
way to go from a finite universe to an infinite
universe is taking an infinite amount of time.
Speaker 1 (38:12):
But if you go backwards, are you saying it would
take an infinite amount of time to compresent infinite universe
an infinite.
Speaker 3 (38:19):
Amount exactly into a finite point?
Speaker 1 (38:21):
But you know, I think the universe is time right,
like the universe not really doing anything else? Do universe
do it?
Speaker 3 (38:27):
It's possible. I mean that state we talked about, that
initial state that we can't explain. We know how far
back that was. That was fourteen billion years ago. What
happened before that? There could be an infinite amount of
time before that, or there could be just five minutes.
We don't know. Right, it's possible that deep in the
infinite past, if it exists, there is a finite origin
to the infinity of the current universe.
Speaker 1 (38:48):
Mmm. So I'll be sort of right. You can sort
of go from a finite universe to an infinite universe if.
Speaker 3 (38:54):
You have infinite time. You have to assume infinity somewhere.
You can't go from a finite universe to an infinite
universe in finite time.
Speaker 1 (39:02):
But maybe the universe had infinite time.
Speaker 3 (39:04):
Maybe it did. We just don't know what the squigglyons
were doing before that moment. We can't describe.
Speaker 1 (39:09):
Yeah, the bits on I think you mean.
Speaker 3 (39:12):
The university news.
Speaker 1 (39:15):
Yeah, the Albinos. We'll call them obinos in honor of Alby,
who apparently sparked the revolution in physics starting today.
Speaker 3 (39:24):
Congratulations on your future Nobel prizes, infinite numbers of them.
Speaker 1 (39:27):
No, no, we get the Noble awesome congrati. But Abby
just gets to be named. Yes, yes, let's be clear here,
or at least I get it. I don't know if
I'll share it with you.
Speaker 3 (39:37):
Well, I hope you have a nice tux.
Speaker 1 (39:40):
I have to buy one. I hope it doesn't cause
it an infinite amount of money, though.
Speaker 3 (39:44):
Just get the T shirt tuxedo. I think that's probably
fine for a cartoonist.
Speaker 1 (39:47):
Oh boy, I wonder how many physicists have been tempted
to do that, you know, like if one of these
hipster physicists that you see on TV, they're like, they
get a Nobel price, but they go into talks or
are they too cool for that?
Speaker 3 (40:00):
I bet there's like a Swedish sniper and ready to
take them out just in case they try that.
Speaker 1 (40:03):
Oh jeez. All right, Well, I think that answers obvious
question depends on your infinities, but also it sort of
depends on maybe the true nature of the universe, whether
infinities are allowed, whether quantum mechanics at some point breaks
this idea of things being infinitely small.
Speaker 3 (40:25):
Real question is what happened before that hot dense state.
The first thing that we can describe with our laws
of physics, and in the end, it all comes down
to quantum gravity, the biggest open question in modern physics.
How do we reconcile gravity and quantum mechanics so we
can describe a state denser that can be described with
our quantum theory.
Speaker 1 (40:43):
All right, well, thanks to everyone who asked their questions
here today. We hope you enjoyed that. Thanks for joining us.
Speaker 3 (40:53):
For more science and curiosity, come find us on social
media where we answer questions and post videos on Twitter, Discorg,
Insta and now TikTok. Thanks for listening and remember that
Daniel and Jorge Explain the Universe is a production of iHeartRadio.
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
(41:14):
or wherever you listen to your favorite shows.
Hey, Daniel, how long have we been doing this podcast?
Speaker 2 (00:10):
Now?
Speaker 3 (00:10):
Oh? Man, I'm not sure. Kind of feels like forever.
Speaker 1 (00:14):
Do you think we could go on forever?
Speaker 3 (00:15):
I don't know. I don't think we're going to run
out of topics.
Speaker 1 (00:18):
You think there's an infinite number of questions we can
talk about in physics.
Speaker 3 (00:23):
I think you could just keep asking why forever? Yeah?
Speaker 1 (00:26):
Why do you think that is?
Speaker 3 (00:28):
I think you just proved my point.
Speaker 1 (00:29):
Wait, what do you mean why? Q ed you pretended
to say just because I said so ardude.
Speaker 3 (00:37):
Because the universe says so. Universe is the ultimate?
Speaker 2 (00:41):
Dad or Mom?
Speaker 1 (00:57):
Hi, I'm orham Mack, cartoonists and the author of Oliver's Universe.
Speaker 3 (01:01):
Hi, I'm Daniel. I'm a particle physicist, a professor at
UC Irvine, and I think I'll always be asking why, why?
Speaker 4 (01:07):
What?
Speaker 3 (01:09):
Why this universe and not some other universe. Imagine some
moment in the deep future when we see the final
theory of the universe that describes the most fundamental basic bits.
I think people are still going to look at that
idea and wonder, why does it work this way? Why
couldn't it have been different?
Speaker 1 (01:27):
What if you get to the end Daniel, and you
figure it everything out, and the answer is just because.
Speaker 3 (01:35):
Is that really an answer?
Speaker 1 (01:36):
Though it is, I give it to my children all
the time.
Speaker 3 (01:40):
I don't know if that's an answer or a cop out.
It kind of means like there is no answer, you know.
One version of the answer is, Look, the universe could
have been lots of different ways. It just is this way,
which means there's fundamental randomness, not just in the operation
of the universe, but in the very laws that government.
Speaker 5 (01:56):
Right.
Speaker 1 (01:57):
But it's still an answer that wouldn't be satisfying. Ye,
going to sleep soundly that night, and just one night
after that, you'll be totally fine. I see how deed
your physics roots go.
Speaker 3 (02:08):
I'll have one long dark night of the physics soul.
Speaker 1 (02:11):
Yeah, and then you're over it. Yeah, that's fine.
Speaker 3 (02:15):
You've got to embrace stuff and move on. You know,
no point in holding grudges against the universe.
Speaker 1 (02:20):
Well, speaking of moving on, Welcome to our podcast, Daniel
and Jorge Explain the Universe, a production of iHeartRadio.
Speaker 3 (02:26):
In which we refuse to move on until we understand
something and explain it in an understandable way to you.
We think, we hope we pray that the universe is understandable,
is explainable, is digestible by our petty little human minds,
and we do our best to bring you up to
the forefront of human knowledge and the abyss of human ignorance.
Speaker 1 (02:45):
That's right, because there is still a lot that we
don't know about the universe, a lot to discover, a
lot to find out, a lot to explore. In fact,
maybe we should rename this podcast Daniel and Jorge wonder why,
although is that taken? Is that taken?
Speaker 3 (02:58):
It's a great name for a show, and somebody should
really do that.
Speaker 1 (03:01):
Yeah, somebody should make a yeah TV show maybe for kids.
Speaker 3 (03:04):
Yeah, exactly, Yeah, replace our names with some kids name
or something. I don't know, we'll figure it out.
Speaker 1 (03:08):
Yeah, an awesome girl's name. Perfect. I'm sure they'll give
us a show, even though we've never made one before.
Speaker 3 (03:16):
Now you're just being ridiculous.
Speaker 1 (03:18):
Yeah, who would do that?
Speaker 3 (03:19):
There are a lot of amazing mysteries in the universe
things to wonder about, not just whether two total nubes
can make a TV show on PBS, but questions about
the nature of the universe, how it works, why it
works this way not some other way. Unfortunately, we have
not yet run out of those questions.
Speaker 1 (03:35):
Yeah, it seems that human curiosity is sort of endless,
and we have evidence of that from all the questions
that the podcast receives from listeners.
Speaker 3 (03:43):
Because the process of doing science is tapping into those
human questions to wonder, why is it this way not
some other way? How does this idea fit with that
other idea? Can I click them both together in my head?
When they don't quite fit? That's an opportunity to learn something,
maybe to reveal something about the universe. That's how science
moves forward. People asking questions, and those people are podcasters, scientists,
(04:05):
television show producers, and everybody else who wants to understand
the universe.
Speaker 1 (04:09):
Yeah, we get lots of questions, and sometimes we actually
answer those questions here on the podcast, questions that we
feel everyone would enjoy thinking about and finding out what
the current answer and science is.
Speaker 3 (04:21):
That's right. But even if your question doesn't make it
to the podcast, you will still get an answer. I
will write back to you and try to help you understand.
So please, everybody, don't be shy write to us to
questions at Daniel and Jorge dot com. We really will
right back.
Speaker 1 (04:36):
So to the end the podcast, we'll be tackling listener
questions Number fifty three Daniel Hoffen. Do we do these now?
About every month we answer listener questions.
Speaker 3 (04:49):
We used to do it about every month, but we've
been getting a lot more questions recently, so I've uped
it to almost every week to try to catch up.
Speaker 1 (04:55):
Wow, what do you think is causing this increase in questions?
Speaker 3 (05:00):
Good question, I'll add it to the list.
Speaker 1 (05:02):
We'll spend an episode talking about why we get more
questions in the episode, and then we'll implode. We'll implode
from the paradoxical nature of this.
Speaker 3 (05:10):
The infinite recursion in that question will generate information density
that creates a black hole podcast.
Speaker 1 (05:15):
Yeah, and then we'll be able to go on forever.
Speaker 3 (05:19):
That's called the singularity.
Speaker 1 (05:20):
Because then the next episode will be yes, how are
we doing a podcast while we're getting questions?
Speaker 3 (05:26):
I can just see it alien anthropologists in the future
trying to figure out how human civilization ended in a
podcast singularity.
Speaker 1 (05:33):
Well, hopefully we're not the end of civilization, but maybe
the beginning of a lot of people's questioning about the universe.
And so we have three awesome questions here today that
we're going to try to answer or at least talk
about great questions about the strong force, about the creation
of matter, and about the infinity of time. Hopefully this
podcast will not be an infinite length of time, but
(05:56):
we hope your love for it is infinite no matter
what kind of matter we talked about.
Speaker 3 (06:01):
I hope anti matter doesn't lead the anti love.
Speaker 1 (06:03):
Yeah, that would be a strong statement. All right, let's
dig into our first question, and this one is from Emily.
Speaker 3 (06:09):
We actually have two questions here from Emily and from
Sarah that asked related questions. I thought we could answer
all together a double question.
Speaker 4 (06:17):
All right, Hi, Daniel and Joje. Here's Emily and I
have a few questions about the strong force. First, how
does the strong force even really work? And how can
it be that it gets stronger with the distance? Does
that ever end? As in, is there a maximum strength
(06:39):
to the strong force? Because it cannot get infinitely strong?
Speaker 3 (06:45):
Right?
Speaker 4 (06:46):
If it did, we could never break apart of proton,
could we? And one more question, If I had the
strength to pull two quarks.
Speaker 6 (06:58):
Away from each other, would I at some point need
infinite strength to keep pulling? Thanks for answering my question.
I really like your podcast. Keep up the great work.
Speaker 7 (07:12):
Hi.
Speaker 8 (07:13):
I want to ask about the strong force. What is
the strong force? What does it do? Why is it
so strong? Why is it so difficult to understand and calculate?
And why is it range considered shorter than electromagnetisms.
Speaker 1 (07:34):
All right, some pretty strong questions here, Daniel. Do you
think we're strong enough to answer it?
Speaker 3 (07:39):
I hope. So the strong force is tricky. It is
complicated stuff, and these are great questions trying to get
intuitive understanding of how it all works.
Speaker 1 (07:48):
I like how she phrased the question Emily here, how
does that even work?
Speaker 3 (07:54):
How does it all even work? Can we just describe it?
How can we actually explain it?
Speaker 1 (07:59):
All? Right? Well, we had two questions that we'll tackle
one at a time. Daniel, How does the strong force work?
And why does it get stronger with distance?
Speaker 4 (08:07):
So?
Speaker 3 (08:08):
The strong force is a force between any particles that
have color charge. Color charges is like a version of
electric charge. You know how electrons have negative charge and
protons have positive charge, and that's how you know they
attract each other or to electrons will repel each other.
In a strong force, we have a different kind of
charge we call it color, and any particles that have
(08:29):
these color we say feel the strong force. This is
just kind of descriptive the way we gave labels too
particles to describe their charge, to explain the forces we
see pulling and pushing between them. We give these colored
labels to quarks to describe the forces that we describe
between them.
Speaker 1 (08:46):
Well, maybe taking a step back, the strong force is
one of the four fundamental forces that businesses have noticed
about the universe, and these are the forces that pull
and push matter together or apart.
Speaker 3 (08:57):
That's right. It depends a little bit how you count
the forces. Some people say two, some people say three,
some people say four. And the four force version you
have gravity, which is not really a force, and then
you have electricity and magnetism as one force, the third force,
and then the strong forces the fourth and the more
simplified version, we say gravity is not a force, you
don't count it. Electricity and magnetism have been combined with
(09:20):
the weak force into the electro weak force, and then
the second force is the strong force. So in the
sort of unified version, you really only have two forces,
electroweak and the strong force.
Speaker 1 (09:31):
And so the strong force is the one that pushes
and pulls quarks, right.
Speaker 3 (09:36):
Yeah, that's right. Anything with a color charge, which means
quarks and also gluons, electrons and muons, and those particles
don't have a color charge, so they just don't feel
a strong force the way a neutral particle doesn't feel
an electric field.
Speaker 1 (09:49):
Okay, and so part of the Emily's question is how
does it get stronger with distance? So does it get
stronger with distance? Meaning if you pull the quarts apart,
they're actually going to be pulling the dwarf each other
or apart more.
Speaker 3 (10:02):
Yeah, it's really weird and very counterintuitive with gravity and
with electromagnetism. If it's attracting two particles and you try
to pull them apart, it gets easier as you get
further apart. Imagine a proton an electron and you're holding
onto them with tweezers and you're pulling them apart. As
you succeed in pulling them further and further apart, the
force on them gets weaker and it gets easier and easier.
(10:22):
But with a strong force, we notice something different. We
notice that after a certain distance, the force stays constant,
doesn't actually grow with distance. It stays constant. So after
about like the width of a proton, if you pull
two quarks apart, the force on them is the same
no matter how far apart you pull them.
Speaker 1 (10:39):
Wait, what so it doesn't get stronger with distance only
for a little bit.
Speaker 3 (10:43):
It decreases with distance until you get about a proton's
width apart, and then it stays constant. It doesn't fall
off like one of our are square, the way electromagnetism does.
Speaker 1 (10:53):
Oh so the strong word doesn't get stronger with distance.
Speaker 3 (10:56):
Doesn't get stronger with distance in the sense that the
force doesn't increase, but the amount of energy stored in
that bond does because forces like the slope of the energy,
and so the energy is actually just growing and growing
as those two quarks pull apart.
Speaker 1 (11:10):
But the ford doesn't get stronger, right, doesn't get stronger.
There's just more potential the more you pull them apart.
You just like maybe you have more gravitational potential the
higher you go up a ladder.
Speaker 3 (11:21):
Yeah, exactly, And this feels weird compared to like electromagnetism,
but it's not so unintuitive.
Speaker 4 (11:26):
You know.
Speaker 3 (11:26):
You take a rubber band, for example, and you pull
on it. The force doesn't drop as the rubber band
gets stretchier and stretchier. Right, So there are some kinds
of analogies we have in the everyday world. But Emily's
probably wondering, like, why does this happen? How does it
work this way? And that's not something we really understand.
This is just our description of what we see happen
between particles.
Speaker 1 (11:46):
Part of our question is is there a maximum to
the strong for it? I guess she was imagining that
the strong force was like a rubber band. The more
you pull it apart, the stronger it gets. And so
she's wondering, is there a maximum to this force? Can
it just be infinite if you pull the two things
apart infinitely? But it sounds like you're saying that this
wouldn't really happen.
Speaker 3 (12:06):
It wouldn't really happen because the energy can't grow to infinity. Like,
as you pull these things apart, the four states constant,
but the energy stored in that bond just grows and
grows and grows and grows. But at some point there's
so much energy in that bond that the universe prefers
to transfer that energy into mass, to convert that energy
into quarks because quarks are actually pretty light. They don't
(12:26):
take a lot of energy to make. So the universe,
which prefers to spread energy out rather than have it
concentrated in one bond or in one state, will prefer
to create a bunch of quarks out of that energy.
So you have these two quarks that you're pulling apart.
The universe prefers to create more quarks to shorten the
distances between quarks, spending that energy to create the mass
(12:46):
and reducing the energy of the bonds.
Speaker 1 (12:48):
Well, what so I take two quarks they're held together
by the strong force, I pull them apart, and at
some point, like what kind of distance that we're talking about,
like a meter.
Speaker 3 (12:58):
We're talking about like the width of a proton.
Speaker 1 (13:00):
Oh okay, so a little smaller you pull them apart
the width of a proton, and then what like new
quarks pop up in the middle. You'd have to pop
up two new ones, right, One of the two new
ones is going to be attached to one of my
original protons, and the other new one is going to
be attached to the second of my original quarks.
Speaker 3 (13:18):
Yeah, exactly, And we do this all the time at
the Large Hadron Collider we create a quark and antiquark
pair with a lot of energy, so they're flying apart
super duper fast, almost at the speed of light, and
very quickly. What happens between them is you create another
quark antiquark pair. So instead of having a quark anti
quark a certain distance apart, now both of those have
a new partner to be bound with at half the distance,
(13:41):
and then those start to fly apart and that band snaps.
So you get this whole shower of quarks and anti
quarks being created. All that energy is converted into a
whole stream of new particles, and they like to stay
close together to minimize the energy stored in those bonds.
Speaker 2 (13:55):
Hmmm.
Speaker 1 (13:56):
Interesting, all right, so then you couldn't get to infinity
at some point. It's like the rubberband breaks, yeah kind of, yeah, exactly.
Speaker 3 (14:03):
It's like the rubber band prefers to snap rather than
to stretch out to infinity. And so in principle, you
could have a universe where two quarks are infinitely far apart,
holding infinite energy, but in practice the universe prefers to
spread that energy out. It's basically just entropy that very
unlikely to happen. The universe prefers configurations with more probability,
which means the energy is more spread out, and so
(14:25):
it replaced that infinite energy bond with a lower energy
bond and a bunch of quarks.
Speaker 1 (14:31):
So I guess the strong force is not that strong.
It snaps at some point.
Speaker 3 (14:36):
It's so strong and energetic that it usually breaks down.
Speaker 1 (14:39):
Yeah, all right, then, now Sarah's question our second question
of this question. See you're the one introducing recursion here.
We have two questions inside of one question. Sarah's question
is why is the strong for so strong? Now? Is
there actually an answer to that?
Speaker 3 (14:54):
There's not a great answer to that. There's a terrible
answer and a less terrible answer. Totally terrible answer is
this is just what we measure. We go out in
the universe. We measure the force between particles. We can
measure the strength of stuff. We can say, for example,
gravity is much weaker than electromagnetism, because if you take
two particles, you mostly feel electromagnetism between them rather than gravity.
(15:15):
Gravity is so much weaker. In the same way, we
can compare the strength of electromagnetism to the strong force
and say, hey, between two quarks which have both kinds
of charge, which force is dominating the interaction. So those
are just measurements we make out in the universe, just
numbers the way we measure like the speed of light
or planks constant. These are just things we see in
the universe.
Speaker 1 (15:36):
So basically, you're saying because you said so, because that's.
Speaker 3 (15:39):
What the universe is showing us. The slightly less terrible
answer is that we think at an earlier moment in
the universe, all the forces had the same strength. We
talked about this recently on the podcast. A lot of
these forces, their strength depends on energy, like how fast
particles are going, how much energy they have, the forces
get stronger or depending on the energy and the energy
(16:02):
density of the universe varies with time, like it used
to be hotter and more energy dense in the early universe.
So we think in the early universe, if you sort
of rewind the clock, a lot of these forces might
have had the same strength. So it might be that
very early in the universe the strong force and the
electroweak force were both the same strength, and then something
happened when the universe cooled, it like cracked in an
(16:24):
asymmetric way to give one of them more strength and
one of them less strength.
Speaker 1 (16:29):
WHOA, So there was like an option the universe had.
Is that what you're saying, Like it could have been
a different way, but somehow it broke that way, or
it could it have only broken this way?
Speaker 3 (16:38):
Yeah, we don't understand that. This is something in physics
we call spontaneous symmetry breaking, when the universe had a symmetry,
a balance, and then it cracked as it cooled. A
famous analogy for this is like you sit down at
a dinner table and you have silverware to your left
and silverware to your right. Which one do you pick? Well,
if you pick to your left, then everybody's going to
have to pick to their left. If you pick to
your right, everybody's gonna have to pick to your right.
(17:00):
And another example of this is the Higgs boson. As
the universe cools, all the particles started out having no mass,
but then the Higgs field gives mass to particles, but
not in a symmetric way. It made like the W
and the Z very massive and left the photon massless.
This is called electroweak symmetry breaking. So as the universe
cools and enters another phase, some of these symmetries crack
(17:22):
in a way we don't fully understand.
Speaker 1 (17:24):
So then are you saying that at different universe where
the strong force wasn't a strong that's a totally plausible,
mathematically possible universe that we could have been living in.
But somehow we're living in this universe where the strong
force is strong.
Speaker 3 (17:37):
It might be that those universes are equally possible, or
it might be that there's a reason that it cracked
this way and not some other way. It's not something
that we currently understand, so it's possible, But it might
be that we discover that there is a reason why
the strong force cracked this way and the weak forces
cracked the other way. Are currently we don't know why
it's so strong?
Speaker 1 (17:55):
Do you think it was random?
Speaker 3 (17:57):
There's so many different theories, some that control it, some
that even random. The true description of the universe is
probably something we haven't even thought of yet, so it's
still a deep question.
Speaker 1 (18:07):
I think the real question is if the strong force
hadn't been so strong, would you just still have called
it the strong force?
Speaker 3 (18:14):
We probably would have named it terribly. That's for sure.
Speaker 1 (18:17):
It could have been strong force.
Speaker 3 (18:20):
We have a pretty weak game in naming things. That's
what's constantly across the multiverse. It a strong bias here
because the strong force is so strong, it makes it
really difficult to use. To another part of Sarah's question,
why is it so difficult to do these calculations? And
the reason is its strength. It's hard to do calculations
with a force that likes to pop off all the time.
(18:41):
It's crazy reactive because it makes it much more sensitive
to getting the details wrong. Get a little detailed wrong,
it propagates to a much bigger mistake. That's not true
for the weak force, where mostly things just fade out anyway.
So you make a little mistake, it's going to fade
away and not affect your calculations. The strong force is
like recursive, It builds on itself, and so little mistakes
become bigger mistakes.
Speaker 1 (19:02):
M Terry volatile huh, yes, exactly. All right. Well, so
then to answer Sarah's question, it's either because if we
said so, or we don't know.
Speaker 3 (19:12):
Either there's no answer or there's an answer we haven't
found yet.
Speaker 1 (19:15):
That basically covers every possibility because just because.
Speaker 3 (19:21):
Keep digging, Sarah, keep digging.
Speaker 1 (19:22):
All right, Well, thank you, Emily and Sarah for those
great questions. Now let's dig into our second question, and
this one is about the creation of matter, So let's
dig into that. But first let's take a quick break.
(19:47):
All right, we're answering listener questions here, and our second
question comes from Trevor.
Speaker 5 (19:52):
Hey, guys, this is Trevor from Pittsburgh, Pennsylvania. I appreciate
you taking my question. I've been thinking lately about the
origin of the matter that we come across in everyday
life that just makes us up and makes up all
of our stuff, right, and how most of it probably
came from stars that fuse hydrogen into heavier elements naturally.
(20:13):
My presumption when I was thinking about this was that
most of the particles that make all this stuff around
us up probably spent some or possibly even most of
their existence as parts of hydrogen atoms before those atoms
were fused into heavier elements. But the more I think
about it, the less confident I am in this presumption.
Do we actually know anything about how much of the
(20:35):
normal matter that exists today has at some point been
a part of a hydrogen atom, And if there is
matter that has never been a part of a hydrogen atom.
Why not? And where is it? I think this whole
line of questioning brings up yet another question. Does it
even make sense to think of quantum particles as having
a long history like this or are they more kind
(20:57):
of ephemeral in nature. I really look forward to hearing
what you guys have to say on this. Thanks again.
Speaker 1 (21:02):
Well, it seems like Trevor here is asking about the
origin of matter, and the part I didn't understand is
exactly whether it could have been part of the hydrogen atom.
What does that mean?
Speaker 3 (21:11):
I think he's asking whether all the heavier bits of
stuff that are out there, iron and lithium and uranium
was once hydrogen. Like is it possible that uranium was
just made from nothing? Or was every atom made from
hydrogen atoms fused together? Is the history of every single
atom that it was once hydrogen I see?
Speaker 1 (21:31):
Or do we have some like original atoms out there
that were made heavy from the very beginning of the universe?
Speaker 6 (21:37):
Yeah?
Speaker 3 (21:38):
Exactly, Like is there any primordial uranium in the universe
that was never hydrogen? Whereas hydrogen the only path to
becoming an atom?
Speaker 1 (21:46):
Right, And we actually talked about this in our last recording.
Speaker 3 (21:48):
Did we Yeah, we talked about this in the Origin
of Matter a few times. It's a really fascinating concept.
It's incredible to me that we understand so much about
the early universe that we can talk about how madam
was and how it was fused, like down to the
seconds and microseconds.
Speaker 1 (22:03):
Well, I guess maybe there's two questions here. Is one,
can you make heavier matter instantly just from like the
basic building blocks of the universe without going through the
hydrogen atom? And the second question is what actually happened
in the Big Bang? Did something like that happen or
did all the matter in the universe go through hydrogen? First?
Speaker 3 (22:22):
Yeah, so let's trace the sort of early history of
the universe to answer this question. You start out like,
before there were any particles, you know, what was in
the universe. Well, the furthest back we can go is
to say there was some very hot dense state. We
don't know where it came from, we don't know how
it was made, we don't know what came before that.
Just start with the assumption you have some hot dense state,
(22:43):
and everything expands. That hot dense state becomes less hot
and less dense, so it becomes colder and more dilute.
So you have all this energy in these frothy quantum fields.
As it cools down, you can start to talk about
particles emerging from these fields the way like a room
that's flooded is just filled with water, and then as
you drain it, you end up with like droplets on
(23:04):
the floor. So now the universe is sort of filled
with the most fundamental particles quarks and electrons and stuff
like that.
Speaker 1 (23:11):
Before it was just pure energy like this is before
there were even quantum fields. Like the universe was so
nuts so that you couldn't stand being there.
Speaker 3 (23:19):
We don't know what comes before fields. The nutso state
of the universe is not something we can even describe.
There's some vague theories about it, you know, inflotons decaying
into quantum fields, but it's all very speculative. In question markye,
the first moment we can describe is the universe filled
with quantum fields. But those fields are so washed with
energy that it doesn't make sense to talk about particles
(23:39):
yet in those fields. It's only as those fields calm
down and cool that it makes sense to talk about particles.
As ripples in those fields, and.
Speaker 1 (23:47):
They calm down, cool because they were getting stretched.
Speaker 3 (23:50):
Out, right, Yeah, because as the universe expands, there's the
same amount of matter in it, so that matter gets
more dilute, right, and so you end up with particles
rather than just huge piles of enery.
Speaker 6 (24:00):
Right.
Speaker 1 (24:00):
But those first particles are not atoms. They're the building
blocks of atoms, meaning quarks. Right, So before you even
had an atom, you had a whole bunch of quartz
floating rep.
Speaker 3 (24:09):
Yeah, not just quarks. You have quarks, and you have gluons,
you have photons, you probably have dark matter, you have electrons.
You have all the sort of basic building blocks. And
we don't know that these actually are the most basic
building blocks. Just our current theory could be that quarks
are made of something else, quigglyons, and the squiglyons were
made first. But in our current description you end up
with quarks and gluons and photons and dark matter. No
(24:32):
atoms yet. Absolutely, it's still too hot for atoms to
even form.
Speaker 1 (24:36):
Right, So we had the basic particles quarks, gluons, and
then eventually those quarks fuse together to form protons and
neutrons exactly.
Speaker 3 (24:44):
The strong force is pulling on all those quarks. There's
a huge amount of energy. But then as things cool,
the strong force pulls those quarks together to make protons
and neutrons and other kind of bound states of quarks.
Here's a strong force at play pulling those quarks together.
Doublets of quarks like quark antiquark pair, we'll give you pions.
Triplets of quarks will give you protons and neutrons. That's
(25:07):
the moment when you go from like free particles to
bound particles, when the universe gets cold enough to bind
those quarks together.
Speaker 1 (25:14):
Right, right, Well, assuming that quarks and gluons and photons
are fundamental particles, right, isn't it, there are still the
possibility made they're made out of smaller particles.
Speaker 3 (25:23):
Yeah, exactly. If they're all made out of squiglyons, then
first you start with the squigglyons, which then coalesce into
the quarks and gluons, et cetera.
Speaker 1 (25:30):
Is that the official name squigglions?
Speaker 3 (25:33):
What's the macaltons, the wacinions? You know, who knows who
knows ons?
Speaker 1 (25:39):
Just to be clear, that's not the official name, right,
she made that up.
Speaker 3 (25:42):
I'm not aware of any theory of squig lyons. I
just made that up. Yeah, did it sound official?
Speaker 1 (25:47):
If it's every thing, I think you should get credit
for it.
Speaker 3 (25:50):
Oh yeah, you like that name, squiglyons. You think we
should be teaching generations as students about it.
Speaker 1 (25:55):
I think it's as good as quarks and gluons.
Speaker 3 (25:59):
You know, there's a big fight about the name of quarks.
There was one guy I wanted to call them quarks
and somebody else wanted to call them aces and the
quarksky one Mmmm. Yes, yes, I.
Speaker 1 (26:07):
Think we covered this in depth already, all the quarks
of it.
Speaker 3 (26:11):
But that moment when quarks come together into protons and
neutrons already have hydrogen. Essentially, the proton is a hydrogen nucleus,
so physicists consider a proton.
Speaker 1 (26:21):
Hydrogen even though it doesn't have an electron to make
it a whole atom.
Speaker 3 (26:25):
Yeah, we distinguish between the hydrogen ion just the proton,
and the neutral hydrogen atom, which is a proton and electron.
Speaker 1 (26:33):
So wait, are you saying that a proton is an atom?
So why do we even have the word proton?
Speaker 3 (26:38):
Why do we even have the word proton? Well, who's
the one getting philosophical there?
Speaker 2 (26:41):
Man?
Speaker 3 (26:41):
Why don't we even think about protons. We use protons
to count which atoms are which right, Helium has two,
lithium has three, et cetera, et cetera. So it's definitely
a thing in the universe we want to identify. But
when you have only one of them, we consider that hydrogen.
Even if you don't like that explanation, you think like,
protons are not hydrogen yet, then those protons do something
funky well before they find their electrons. In those first
(27:05):
few moments, there is still enough energy for those protons
to come together and make heavier elements like helium. So
in the first few moments after the Big Bang, you
make protons, you make neutrons, and then you also squeeze
those protons together to make helium. So then the question
is that helium did it once used to be hydrogen?
That's essentially what Trevor is asking. If you made primordial
(27:26):
helium right then during the Big Bang fusion, do you
still count that as having been hydrogen? I say yes,
because you didn't make the helium directly. You didn't make
like a proton proton pair directly out of quarks. You
made the protons first and then you fuse them together.
Speaker 1 (27:41):
Aren't you assuming a certain order, like that helium was
made out of two protons. But could like you know,
six quarks have come together to instantly make a helium
atom without ever being two protons in the middle.
Speaker 3 (27:56):
Yeah, great question. The standard story is that you start
with protons and neutrons. Neutrons are crucial here because onder
a few stuff together. You need the neutrons to be
like a buffer between the protons. You can't just fuse
two protons together to make helium. You end up making
like helium three in helium four because you need those
neutrons to keep those protons from being so close together.
Speaker 1 (28:16):
But it's still helium, isn't it.
Speaker 3 (28:18):
It's still helium because you only have two protons. I'm saying.
You don't just make two protons together. You also need
those neutrons. So in order for the scenario where you
make helium from nothing, you also have to make those
neutrons at the same time. But it is possible, Like
I think it's unlikely. I think it's much more likely
for protons and neutrons to be made first and then
come together to make helium. But technically it's not impossible.
(28:42):
You have this big soup of quarks and gluons, and
as it's cooling, it is possible for an entire helium
atom to coalesce out of that soup without ever having
been hydrogen.
Speaker 1 (28:53):
M And you can keep going right, like, maybe some
carbon also was created spontaneously. Maybe even some uranium was
created spontaneously in the Big Bang. Is that possible.
Speaker 3 (29:04):
It's possible. Now, uranium is unstable, so if you did
make primordial uranium, it would have decayed, but you could
have made like primordial lead, which is the heaviest stable element.
Now we're talking about really really tiny possibilities. And the
only reason we can't say it's totally impossible is because
if the universe is really vast or even infinite, then
anything that's super unlikely is gonna happen. And we want
(29:25):
to give Trevor as accurate an answer as possible. And
so it could be that there is an atom out
there made of lead which was created during the Big
Bang without ever having been hydrogen. But the overwhelming majority
of stuff in the universe that's made of atoms almost
certainly was hydrogen.
Speaker 4 (29:44):
First.
Speaker 1 (29:45):
The way you're saying there could have been one lead atom,
but only one, like given the observable universe, but the
universe that we can see. Do you actually have a
number for your estimated probability of this happening or are
you just kind of making it up in your head
right now.
Speaker 3 (29:58):
No, I'm just saying it's possible that the is one.
I mean, the probability of forming even helium directly out
of those quarks is so astronomical I think I would
bet against there being one in the observable universe. So
now if you're going for a lead, yeah, I'm not
going to take that bet either, but it is possible,
so you can't rule it out.
Speaker 1 (30:16):
We are talking about the astronomical probabilities, all right, So
then the answer is Daniel Wooden bet one. But it
is still possible to create matter that was not hydrogen first.
Speaker 3 (30:27):
Yeah, exactly. And Trevor also asked this follow up question
about like the nature of quantum particles. Can you think
about them having a long history or this sort of
a femarole, And this is a good philosophical question, you know,
you could ask like when is a photon the same photon?
If the photon bounces off of a wall, is it
the same photon or was it absorbed and recreated, and
(30:48):
that in the end is a philosophical question and sort
of an arbitrary distinction. You know, the information in the
universe flows through these particles and is preserved in those
quantum states, whether you count it as the same particle
or not. It's sort of like the question of whether
the Star Trek transporter actually kills you and recreates you
or transports you literally to another location. It's really more
(31:09):
of a philosophical question than a physical one.
Speaker 1 (31:11):
I see, Trevor, I hate another question here in this question.
He tried also to go recursive. Now is it still
a question, Daniel? If it has two questions inside of it.
Speaker 3 (31:21):
That's a good question.
Speaker 1 (31:23):
Yeah, let's keep going. Now why is it a good question?
All right? Well, Trevor, I think that answers your question.
Thanks so much for sending that in. And now let's
get to our third question, which is about the infinity
of time time time. So let's dig into that. But
first let's take another quick break. Or we're answering listening
(31:56):
to questions here today, and our third question comes from
I'll be.
Speaker 7 (32:00):
Hi, Daniel and Jorge. In any finite period of time
being constrained by the laws of physics, finite extents in
time or in space could never become infinite at least,
I think, how does physics, then, given the proposed finite
age of the universe, contend with the real possibility of
(32:24):
an infinite universe? Would it have had to have been
born infinite? If indeed it can't grow from finite to
infinite size, and working backward from a finite or infinite size,
how could that have grown from a universe that was
infinitesmally small?
Speaker 1 (32:44):
Thank you all right? I feel like this question is
also recursive in or at least it's giving me a
bit of a headache here talking about the different infinities.
I think what Abbi's asking is, do you need infinite
time to make an infinite universe?
Speaker 3 (33:00):
Exactly? And I think obvious Struggling to reconcile two ideas
that are out there in the sort of popular science universe.
One is that the universe might be infinite, could go
on forever and ever and ever, even beyond what we
can see, So the full universe, beyond the observable universe
could be infinite in extent. That's one idea, And the
(33:21):
other is this conception of the Big Bang as the
universe having started from a point that there was a
tiny dot of stuff and everything flew out from that dot.
That dot seems finite, and so I think Abby's wondering, well,
how do you start with this finite dot then end
up with infinite space filled with infinite stuff? That seems
like a disconnect.
Speaker 1 (33:41):
Right, right, because I guess the way the Big Bang
is usually percented, it does start with a dot, and
a dot seems finite.
Speaker 3 (33:48):
Exactly, and there's a way to interpret that. It's being
technically correct, but I think mostly it's misleading. People think
of the Big Bang as this tiny dot, like smaller
than an atom, containing all the matter in the universe,
which then expands ended out into empty space, and people
wonder like, well, how could that turn into something infinite?
And the way that we actually think about the Big
Bang is not in that sense at all. We think
(34:09):
about it more in the way that we just described,
And answer the last question. You start with potentially infinite
space already filled with stuff, but there was no empty
space back in the beginning, that everything was already filled.
However much space there was, it was already filled with
some hot, dense state, a state we can't explain. We
don't understand where it came from. But the Big Bang
(34:30):
describes the expansion of the universe from that point. So
there's no empty space. Everything's already filled, and the Big
Bang is not the explosion of stuff through that empty space,
but the expansion of that space, which makes it colder
and more dilute.
Speaker 6 (34:44):
Right.
Speaker 1 (34:44):
I think what you're trying to say is that, like
we think of the Big Bang as a moment of creation,
but you're saying that the Big Bang is not really
when the universe was created. It's just when the universe
expanded from being super compressed to being less compressed. The
universe was there already and it was infinite.
Speaker 3 (35:02):
Yeah, exactly. And that's because we know there's a limitation
to our theories. Like we can talk about quantum fields
and all that stuff describing space, and that works up
to a point, up to a certain density of the universe,
beyond which our theories break down. It's at that point
when everything is so dense that you can't really ignore
gravity anymore. You need a theory of quantum gravity to
describe the universe that is that dense. So before that,
(35:25):
we don't even try to explain. So we start our
history of the universe the first moment that we think
our theories can describe, when the universe is super hot
and super dense, but we think we can describe it
used in quantum field theory. Before that, we have no idea,
question mark, question mark, inflation, instantans, who knows, squiggly ons, whatever.
But the history of the universe begins in the first
(35:45):
moment we can describe, and the big Bang is the
evolution of that universe, the expansion, the cooling and coalescing
into particles, et cetera, et cetera.
Speaker 1 (35:54):
I think maybe what Auby is also trying to kind
of grapple in their heads, is this idea of find
time right, because a lot of physicists say that time
started with the big Dang, possibly, and that there was
no time before. If you sort of run the clock backwards,
at some point, there was no time, and so what
was the universe back then exactly?
Speaker 3 (36:15):
And that's extrapolating past that super dense point using just
general relativity, saying well, what if general relativity is correct
and that's the way time and space works, and we
can ignore the unignorable quantum effects. That's what general relativity predicts.
Predicts that time begins in the singularity of density. But
that's sort of ridiculous extrapolation. We know that quantum theory
(36:36):
needs to be accounted for there. So yeah, if you
extrapolate general relativity beyond where we think it's relevant, then
you get this prediction that time begins at some certain point,
which is also difficult to grapple with. But that's not
something we're confident doing because we know the theory breaks down.
Speaker 1 (36:51):
I see. So the answer is we don't know.
Speaker 3 (36:54):
The answer is we don't know, and we think it's
possible that the universe began infinite, that that first moment,
at least that we can describe the universe was already infinite,
filled with an infinite amount of stuff that then expanded
and cooled into a universe that was larger. Right, you
can take an infinite universe and make it larger just
by stretching it, so you can create new space everywhere
(37:16):
in that universe, making it effectively larger and colder. So
that's how we get to an infinite universe today, is
that you start with an infinite universe. Abby's totally correct
that if you start with a finite sized universe, you
can't then have an infinite universe. Today, we don't know
if the universe is infinite. We can only see a
certain distance out there. We know the universe is huge
and vast. It might be infinite beyond that horizon, or
(37:39):
it might be that it's finite.
Speaker 1 (37:41):
Well, I think maybe Abby is also maybe posing the
question like what happens if you take an infinite universe
and you squish it down to an infinitely small size.
Does it become then a finite universe? Because as we
all remember from Calculus one, if you divide infinity by infinity,
it depends, But one of the positive abilities is that
you get a finite number.
Speaker 3 (38:02):
You get a finite number in the limit, right, which
would take technically an infinite amount of time. The only
way to go from a finite universe to an infinite
universe is taking an infinite amount of time.
Speaker 1 (38:12):
But if you go backwards, are you saying it would
take an infinite amount of time to compresent infinite universe
an infinite.
Speaker 3 (38:19):
Amount exactly into a finite point?
Speaker 1 (38:21):
But you know, I think the universe is time right,
like the universe not really doing anything else? Do universe
do it?
Speaker 3 (38:27):
It's possible. I mean that state we talked about, that
initial state that we can't explain. We know how far
back that was. That was fourteen billion years ago. What
happened before that? There could be an infinite amount of
time before that, or there could be just five minutes.
We don't know. Right, it's possible that deep in the
infinite past, if it exists, there is a finite origin
to the infinity of the current universe.
Speaker 1 (38:48):
Mmm. So I'll be sort of right. You can sort
of go from a finite universe to an infinite universe if.
Speaker 3 (38:54):
You have infinite time. You have to assume infinity somewhere.
You can't go from a finite universe to an infinite
universe in finite time.
Speaker 1 (39:02):
But maybe the universe had infinite time.
Speaker 3 (39:04):
Maybe it did. We just don't know what the squigglyons
were doing before that moment. We can't describe.
Speaker 1 (39:09):
Yeah, the bits on I think you mean.
Speaker 3 (39:12):
The university news.
Speaker 1 (39:15):
Yeah, the Albinos. We'll call them obinos in honor of Alby,
who apparently sparked the revolution in physics starting today.
Speaker 3 (39:24):
Congratulations on your future Nobel prizes, infinite numbers of them.
Speaker 1 (39:27):
No, no, we get the Noble awesome congrati. But Abby
just gets to be named. Yes, yes, let's be clear here,
or at least I get it. I don't know if
I'll share it with you.
Speaker 3 (39:37):
Well, I hope you have a nice tux.
Speaker 1 (39:40):
I have to buy one. I hope it doesn't cause
it an infinite amount of money, though.
Speaker 3 (39:44):
Just get the T shirt tuxedo. I think that's probably
fine for a cartoonist.
Speaker 1 (39:47):
Oh boy, I wonder how many physicists have been tempted
to do that, you know, like if one of these
hipster physicists that you see on TV, they're like, they
get a Nobel price, but they go into talks or
are they too cool for that?
Speaker 3 (40:00):
I bet there's like a Swedish sniper and ready to
take them out just in case they try that.
Speaker 1 (40:03):
Oh jeez. All right, Well, I think that answers obvious
question depends on your infinities, but also it sort of
depends on maybe the true nature of the universe, whether
infinities are allowed, whether quantum mechanics at some point breaks
this idea of things being infinitely small.
Speaker 3 (40:25):
Real question is what happened before that hot dense state.
The first thing that we can describe with our laws
of physics, and in the end, it all comes down
to quantum gravity, the biggest open question in modern physics.
How do we reconcile gravity and quantum mechanics so we
can describe a state denser that can be described with
our quantum theory.
Speaker 1 (40:43):
All right, well, thanks to everyone who asked their questions
here today. We hope you enjoyed that. Thanks for joining us.
Speaker 3 (40:53):
For more science and curiosity, come find us on social
media where we answer questions and post videos on Twitter, Discorg,
Insta and now TikTok. Thanks for listening and remember that
Daniel and Jorge Explain the Universe is a production of iHeartRadio.
For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts,
(41:14):
or wherever you listen to your favorite shows.
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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