November 20, 2018 • 36 mins
What did the Universe look like as a baby? How do we know? Join Daniel and Jorge as they talk with Katie Mack about the early universe, and what they all looked like as babies.
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Speaker 1 (00:08):
Sometimes it drives me crazy thinking about the secrets that
are buried in the past, you know, things that actually
happened that we just don't know the institude. You mean,
like who killed JFK. No, No, I'm thinking bigger, Like
where are my socks after I put them in the dryer?
That's a big mystery. But I'm thinking cosmic size mysteries.
(00:29):
I mean, like who thought two introverts could make his
science podcast? That's an enduring mystery for sure. But I'm
talking about like universe size mysteries, you know, like, you know,
the universe started in one way and no other way,
And what if we could just go back to the
past and watch it and and unearthed these mysteries from
the past. Wouldn't that be amazing? What was it like
(00:50):
as a baby? Basically? Right? Like, was it awkward? Cute? Funny? Tantramy? Hi,
(01:11):
I'm Jorge. I'm the creator of PhD Comics, and I'm Daniel.
I'm a particle physicist work at the Large Hadron Collider
smashing particles together. And this is our podcast Daniel and
Jorge Explain the Universe, where we trying to explain basically
everything in the universe. In a way that makes sense
to you everything the whole universe. Yeah, so to be
on the program, we have the question what did the
(01:37):
baby universe look like? That's right? What did the universe
look like when it was really young, when it was
just formed, or just after it got started to look
totally different from today? Did it look basically like today?
What did it look like? Daniel? What did you look
like as a baby? I looked like a universe as
a baby. Actually, oh good, that's better than me. I
(01:59):
looked really different as a Maybe then I do now
because I have one of these noses that grows sort
of tectonically. So when I was a kid, I had
a tiny, little button nose, and now I have sort
of a very large alpine nose that just continues to
grow through my lifetime. Well, that sounds better than me.
I just looked like an old bald man. Did you
look like Winston Churchill when you were born? I did
(02:20):
a little bit. Actually, my father was named after Winston Churchill,
which is which is a coincidence there. Okay, So the
question today is what can we learn about the universe
from its baby picture? What did the universe look like
as a baby? Yeah, this is an interesting question because
I was thinking the other day, you know, Daniel, how
do you know that you were actually born? Like, how
(02:41):
do you know that you were a baby? I mean
you think I came out this size? Yeah? Basically, right, Like,
how do you know how do you know you didn't
just pop into existence when you were five years old
or you know, like you were growing out of a
test tube and then and then um and then extra
rooted when you were five years old, which is when
(03:02):
sort of your memories start to kick in. Right, extruded.
That sounds like such a pleasant experience. I wasn't born,
I was extruded. Technically we're all extruded. Yeah, but you're
you're right. There's a there's a sort of a larger
question there, which is like how do you know about
yourself and your context and where you came from? And
why is that important? Right? Like I might say to you, like,
(03:23):
I don't know if I was born, you know, at ten,
out of the laboratory and implanted with all these memories
to make it feel like I had a childhood, But
what does it matter? Right? You might say that it
doesn't matter, but I think it does matter. I think
it matters where we come from, what our context is,
what our culture is. In the same way we wonder
about larger things like how is the Earth made? Right?
(03:44):
The Earth's baby picture looked like, how is the Earth extruded? Yeah,
I guess I'm talking about like evidence, you know, Like, um,
it's nice that I have there are pictures of me,
or at least that I'm told it's me as a baby,
so I can sort of trace my development. But if
I didn't have those pictures, I might wonder did I
just pop into existence when I was five? Right? And
(04:05):
you can look at those pictures, and you can see
things about yourself that, you know that tell you something
about who you are, like to your old Jorges already
holding a banana or already cracking silly jokes or you know,
doodling on the wall or something. Their truths about you
that are emerged early on. Right, Like, man, look at
that cute baby. I can only imagine what the baby
(04:25):
is going to grow up to be, Like, how did
such a cute baby turn into this? You know, there's
the mystery, right, there's awesome, magnificent specimen. Yeah, And I
think that every time, for example, I see like an
old time picture of my hometown. You know, I grew
up in Los Almos, and they're all these pictures of
what it looked like during World War Two, and you
know that shaped the history of the town. And when
I see these old pictures, I like saying, like, oh,
(04:46):
look that building, I still recognize that it's an enduring feature.
And all this is destroyed, it was just transient. So
in the same way, I like thinking about the history
of the universe because it teaches us something about how
it was all put together, and you know what it all.
You see things that make it and what it is
like unique, make it, yeah, exactly special. Yeah, And it
(05:07):
tells us a lot about what's happening in the future.
You know, we want to know what's going to happen
to the future because we're invested, we're going to live
in it. Then we better look into the past. And
you know, we've made startling discoveries by doing this. You know,
the whole discovery of dark energy, the fact that the
universe is being shredded apart by some massive, not understood energy,
right that was only discovered by looking into the past
and understanding what the universe used to look like. Right, yeah,
(05:29):
baby talk aside, we're talking about the universe, right, and
how can we tell what the universe was like, you know,
not just a hundred years ago, two thousand years ago,
but fourteen billion years ago? Yeah, exactly what did it
look like? And what can we learn from that? So,
as usually, we were curused to hear what people out
there thought about this question, and so here's what they
(05:50):
had to say. What do you think the early universe
looked like? Um, the baby universe I would think would
be something really compactly dnce in like probably in a
circular looking thing. I would think, yeah, um, probably nothing
(06:11):
in particular, just a bunch of gases and like crazy,
maybe spirals. I don't know, like you know, not no
stars or anything, that's for sure. I guess like a
more extreme version of what it looks like now because
everything was kind of more close even though it's expanding,
so it's like, I know, there was less space in
between everything, So I guess more bright and intense. I guess. Delete.
(06:38):
On the program, we have astrophysicist Katie mac Hi. Katie, Hi,
how are you good? So you're probably one of the
most famous astrophysicists on the internet. Do you have a
huge Twitter following, and uh, that's really cool. Thanks. Yeah,
it's been really interesting. I don't know where all the
people come from, but I'm glad that they are hanging
out and listening to me talk about astrophysics. Can you
(07:01):
tell us a little bit about where you work. I'm
in the physics department at North Carolina State. I'm an
assistant professor, and I'm also part of the Leadership in
Public Science Cluster, which is a new initiative to encourage
connection between scientists and the general public. Very cool. Yeah,
And I think it's important for people that people to
understand that you're not just somebody on Twitter who likes
(07:23):
to talk about science, but you're actually a practicing scientist
who's chipping away at the mysteries of the universe. Yeah.
I'm doing the best I can at that. And your
expertise is in um Yeah, So I do theoretical cosmology,
which is the study of the universe from start to
finish and the evolution of the universe and what's in it.
And my area of specialty at the moment is dark matter.
(07:45):
So I'm interested in what dark matter is and how
it did what it did in the early universe and
all of that, and I'm also interested in black holes
and in the very early universe and the very end
of the universe. What did you think about people's general
knowledge of what the early universe is like? This surprise you.
I think everybody kind of gets the idea that it
(08:07):
was real, different than now and maybe not as structured um,
and that the structure in the universe has come about
over time, which is true. And so help the people
out there understand that. How can we possibly know that?
How do we know what the early universe looked like
at all? We know what the early universe looks like
because we can look right at it. We can actually
see it. We can watch the Big Bang happening. And
(08:27):
there's caveats to that in terms of what I mean
when I say a big bang and what I mean,
but when I say watch it happened. But the nature
of the early universe is one of the most certain
things we we have in cosmology because we can actually
see it directly. So tell us what that means. Where
do you look to see the Big Bang? Well, you
look everywhere? Um, okay, so let me go back a
(08:49):
couple of steps, billion steps. Yeah, yeah, yeah, Why do
we even think there was a big bang? There was
one guy who we talked to without the universe is
like this forever. How do we know that's not true? Right?
We know that the universe is changing with time because
we can see that it's expanding UM. And the way
we see it's expanding is that we look at really
distant galaxies and we see that they all seem to
(09:09):
be moving away from us. The whole universe is getting bigger,
and so the spaces between all of the galaxies is
getting bigger, and that means that every galaxy we see
is going to look like it's moving away from us.
And in fact, the more distant galaxy, the more quickly
it seems to be moving away from us. And so
you know, beyond a certain distance UM, when we get
(09:31):
out into like the open universe, outside of our little
local area, everything is moving apart. And that only makes
sense if the universe is expanding, and if it's expanding
like the same in every direction. So you can look
at that and then you can say, well, if it's
getting bigger than it was smaller in the past, and
you can just kind of extrapolate back and say that
(09:52):
there had to have been a time when everything was
really really really close together. But that's sort of the
question is like, what did things look like when they
were are all sort of on top of each other,
when the universe was that small? How do we know
what it sort of looked like. If you have some
kind of box with stuff in it, and then you
make that box bigger than things get farther apart, it's
sort of cools down because there's there's more space and
(10:15):
things are not bumping into each other as much. And
so if you go the other direction, then the early
universe should have been a lot hotter and denser and
you know, in some sense sort of smaller than it
is now. And so because of that sort of extrapolation,
a bunch of physicists um back in the day said, well,
if that's the case, then all of that heat and
(10:37):
radiation from the early universe should actually still be out
there somewhere. Well why should it still be out there?
I mean, wouldn't it have been absorbed or bounced around?
Since then? What do you mean all that heat and radiation? Okay,
so so this is where it gets a little bit
trippy and complicated, But this is where it also gets
really cool. I love trippy and complicated, but it's really
(10:58):
cool because this is this is where we're actually seeing
the Big Bang. Okay, so the speed of light is
not infinite, which means that if you look at like
the nearest star other than the Sun, you're looking at
something that's four light years away roughly. That means that
the light that you see from that star is four
years old by the time it gets to you. So
you're saying that to look into the past, you just
(11:19):
have to look at things that are far away. Yeah, yeah, exactly,
And so the farther away that you look, the farther
in the past you're seeing. And we have telescopes where
we can see galaxies where the light has been traveling
for like thirteen billion years, you know, So we can
actually see galaxies that are like some of the first
galaxies ever formed in the universe. We can see really
(11:40):
really early objects. If we just keep looking farther and
farther away, then we're looking farther and farther back, and
we're looking at a time when the universe was so
hot and so dense that that part of the universe
was on fire. Every part of the universe was like
this sort of giant fireball. I mean, not are exactly,
(12:00):
but like plasma, right, And so there's some part of
the universe that's so far away that the last like
a little bit of radiation from that fire has been
sort of streaming through the universe just in every direction.
And there's a part of the university so far away
that that little bit of radiation from that fire has
(12:21):
been traveling through the universe and is just reaching us. Now,
that's awesome, And I think the really mind blowing thing
about that is that it comes from every direction. Like,
as you're saying, you look out into the universe, you
look at something that's the age of the universe away.
You're seeing something that was really far away a long
time ago. Now you look at the opposite direction, you're
seeing something which was the other side of the universe
(12:43):
when it was born. Hold On, I have so many
questions for you. But before we keep going, let's take
a short break. Let me change back off a second.
(13:03):
I'm still a little bit confused. Um, So what you're
saying is that you know, there's there are the galaxies
that are the furthest that we can see. Yeah, but
you're saying, like if we point our telescope just to
the right of that oldest galaxy into literally like black nothingness.
Anything we get when we point our telescopes to that
black spot sort of must be as old as the universe.
(13:24):
Like if we see it in an optical telescope, then
we're probably saying something else. But just to the right
of that old old galaxy, there's radiation coming from that
point that has not hit anything until it's hit us.
Then that's been traveling for like thirteen point eight ish
billion years from a time when the universe was only
(13:46):
about years old. Oh, I see, but it somehow ended
up there and then it had to make its way
to us. Well, it was everywhere, I mean, every part
of the universe put out radiation at that time. Like
the universe is this like fireball kind of state, and
the whole universe is cooling at the same time, right,
and so you have the gas is cooling down, and
(14:07):
there's this radiation that's traveling in every direction. That's like
escaping from the time when the whole universe is on fire,
and that light goes in every direction. So if we
look in one direction and we're seeing the early universe,
and then we look in another direction. We're not seeing
the same part of the early universe, right, right, right,
We're seeing different parts of the early universe. But you
(14:29):
have to think of time in a kind of geometric
way for this to make sense, right, So I kind
of like to think of like we have these like
spherical shells of time around us. Okay, so yeah, yeah,
imagine you have your your head is inside this sphere
one ft in radius that's a nanosecond in the past,
and then you know, you build another sphere that's two
(14:50):
nano seconds in the past, and then you build a
sphere that's you know, a light year in radius, and
then you're that's your one one year ago sphere, and
then you just kind of keep going. So you have
these sort of nested spheres of deeper and deeper time.
And at the very end of that, the largest sphere
is the observable universe, and that sphere is this fireball universe.
(15:15):
So you're saying the universe when it was really young
looked like a fireball. Yeah, I mean every part of
it was was plasma. What does that mean, like a
cloud like a gas. Yeah, it was too hot for
Adams to be neutral, so it was protons and electrons
flying around and radiation, so it would have looked like
a fire in the sense that it was just glowing
(15:36):
hot and then over time it's cooled down. So you
wouldn't want to be around in the early universe. No,
it would not be safe. The dangerous baby. Yes, yes,
definitely if you get into like even earlier times, like
the first few seconds and before, like it's like nuclear
reactions in every point of space at all times. You
(15:56):
know it's bad. It gets real bad you go earlier
and there there in the universe. So it was such
a hot mass of soup soupy mess that nothing could
even form. And so that you're saying that fireball um expanded,
that's the big bang, and it dissipated, but we're still
sort of seeing kind of the afterglow of it. Yeah,
(16:17):
And I don't want to I don't want to imply
that the universe was like an expanding sphere, because it
might just be infinite in every direction and not really
have like a shape to it per se. It might
be infinitely huge. We don't know. We don't know for sure,
but but the idea I guess is that you know,
when people go outside and night or even during the day,
(16:39):
they're getting an image of the baby Universe when they
look up. That kind of the idea if they could
see in the microwave spectrum, then yeah, they'd get a
little bit of that sort of glow from the early universe.
It turns out if you if you have one of
those old TVs that picks up broadcast, you know, not
not the digital kind. Little bit of the static on
(17:01):
those things is is the afterglow of the Big Bang,
the cosmic microwave background. So you can actually see the
Big Bang in the snow on old televisions. But but
the picture of the baby Universe is not like snow.
It's not um like a glow or noise. It actually
has like a it's a picture right like it. It's
got a specific texture on it, right yeah. Yeah, So
(17:21):
we can map it out. If we take these microwave
telescopes and look at every point on the sky and
map out the microwave radiation, then we can see where
some points were a little bit hotter than others, and
you can see kind of these patterns of little splotches
for hotter and colder spots on the you know, background
(17:44):
light and the background light. You know, it looks like
a sphere around us, just like if you were in
a planetarium, you'd see, you know, um, the stars and
a sphere around you. And we can look at those
patterns and figure out where, like there was a little
bit more matter in a spot, a little bit less
matter in that spot. And we can see traces of
(18:05):
like sound waves traveling through the early sort of fireball universe,
because it turns out when the universe is that dense,
sound can travel through space. Yeah. Yeah, so the early
universe was like ringing with sound waves and you can
see those in the picture. Yeah, you can see, um,
you can see like patterns associated with like sound waves
(18:27):
traveling through the sort of plasma. So it wasn't just
a hot mess. It was a hot, noisy mess. Yeah.
It sounds a lot like my house on a Saturday afternoon.
Yeah yeah, kind of like real babies, Yeah, exactly, kind
of like a baby hordhead. There you go. So, um,
are you're talking about this very early universe and things
(18:47):
we can learn about how what it meant? And so
what might you learn about the early universe, Like what
kind of result could you get about the early universe
that would surprise you or make you feel differently about
like your life and our rule here in the whole context.
What kind of is could you could you learn that
would change your feeling about, you know, the human experience,
how our universe came to be and why it is
(19:07):
the way it is. That would be really exciting to
find out. There could be other universes that may have
like collided with our universe at early times, and there
are ways to look for evidence of that with the
couse of microwave background, and if that happened, that would
be really interesting to see. And one of the possibilities
for that is that the Big Bang happened because two
(19:30):
universes kind of collided in the past and bounced off
each other, and so there could be like this parallel
universe out there that we might be doomed to collide
with again twins, So that would be really interesting as
well to know that, like there's more spatial dimensions that
we can see, so you know, the universe is kind
of bigger in some direction that we don't understand, So
that would be really interesting. That's amazing. Would it shock
(19:52):
you if fourteen billion years from now people could still
see your baby picture I was such an ugly baby.
The analogy really works because you can look back at kids,
for example, when there were two or three, and you
can see in them the seeds of their current personality.
You can see, oh, it was a fighter, it was
a screamer, a curious baby. So I think there are
(20:14):
truths about us that are hidden in our baby pictures,
the same way our truths about the universe that are
secreted away in the in the cosmic bac away background. Well,
thank you so much, Katie for joining us. It's good
to chat about the the universe. I'm always happy to
do that. Yeah, you're welcome any back, anytime, and people
can find you on Twitter, right, Katie, your your handle
is at a stro Katie. One word right A S
(20:37):
T R O K A T I E. Great, Yes,
that's right. Well, thank you so much for joining us, Katie.
I hear you're working on a really great project these days.
A new book. Yeah, I'm working on my first book.
It's for general audiences, so um, you know, not not technical,
but the topic is the end of the universe, So
where it's all going to go, how it's all gonna end, um,
(21:00):
what that's going to look like. What it means for
the universe to have an end um It's it's should
be really fun. It's called the End of Everything, and
it'll be out in hopefully before the end of the universe. Yeah,
it would be really inconvenient if the universe ended before
the book came out. So I'm crossing my fingers and
hopefully will have a happy ending or is it a
(21:22):
spoiler alert? There aren't very many pleasant ways to destroy
the entire cosmos. This is not a Disney book or hey,
unfortunately great, So I hope everyone checks it out and
keeps an eye for it. Thank you, Katie. Thanks, So
(21:47):
that was really fascinating. Katie told us a lot about
how we can see the history of the universe from
these really really old photons that are come from deep
in space and deep back in time, all the way
back to four hundred thousand years after the Big Bang. Yeah,
when the universe became transparent. That's an interesting constant, right,
Like we think of space is black and full of
(22:09):
stuff in it, but relatively speaking, it's kind of transparent, right,
it's empty, Yeah, which is fantastic. Right. It's good luck
because if the universe was not transparent, we couldn't have
learned all these amazing things we learned about the universe, right,
And you might think, well, of course space is transparent,
but that's the thing, it wasn't always right. Around four
hundred thousand years after the Big Bang is the first
(22:30):
time that it cooled down enough that the hot plasma
Kittie was talking about moved from being ions into being
neutral atoms so that photons could fly through them unimpeded. Right,
So it makes me wonder, what was it? How could
we ever see before that? Can we see before four
hundred thousand years after the Big Bang? We can, but
we can't use photons. You know. It's like staring at
(22:52):
the Sun. Right, you can see the surface of the
Sun because it's shooting our photons, But you can't see
photons from the inside of the Sun because those get absorbed.
And so looking at the earlier history of the universe
requires somehow looking inside this big ball of plasma, and
we can't do that with photons, but looking sort of
in time, right, we want to pierce into it in time,
(23:12):
that's right, And so we can't see directly. One thing
we can do is that we can do experiments to
recreate it. You know, we can say, well, what was
it like when there was so much energy focused in
one place? You mean, we can make babies in a
test tube. I'm not proposing that you and I make
babies in a test before, as much as that would
be on the frontiers of science. And also I think
it's sort of inappropriate to raise that like on air
(23:34):
in the podcast. I mean that should be a private conversation.
You're like buying me a glass of wine. At least
for as Joe, I'm not that easy. Um, we can
recreate the conditions of the Big Bang sort of, um,
just by smashing particles together, so you know, the large
Hadron collider, we smash protons together. Sometimes we even smash
(23:55):
heavier stuff together like lead or gold nuclei and try
to recreate the big hot mess that was that ball
of plasma, just to see what was it like and
what's the physics of it and what happens. So what
do you mean, recreate the conditions like the temperature or
just like the crazy the pure energy nous of it. Yeah,
the density of energy, right, that's essentially what temperature is
(24:16):
in my in my understanding. You know, we're just trying
to create a lot of energy into in one place,
so that quirks, for example, which usually are bound tightly together,
can feel free because there's so much energy around that.
Everybody has so much energy, they don't they don't get
tied down. You're like, be free, quargs, be free, take
off your foes. It's the Cork Liberation Front is whatever.
(24:39):
The Q left is sort of a militant group there. Um. Yeah,
so you can sort of think of the LHC is
like a big bang machine. You know, every time we
collid were like recreating these collisions and so we can
study that experiment. Makes me a little nervous that, Daniel,
just like, what's what's the big deal? Because me like
a big bang machine. First of all, it sounds kind
of it sounds a little inappropriate. But like you made
(25:01):
a machine that makes the universes. That's a that's a
little worrying, isn't it. Well, it only makes forty million
universes a second, what what could go wrong? No, seriously,
people don't worry. We're not We're not creating universes at daily. See,
we're creating the We're recreating the conditions of the early
universe by making something that's as hot and dense in
(25:21):
a very small space, and we're all wearing life jackets
and hard hats and nobody should be concerned and diversion. Yeah,
and the point is that what we're just trying to
study it, and because we have these theoretical models that say,
we think we know what happened before four thousand years
after the Big Bang, that's the last thing we can
directly see. We think we know what happened before that,
so let's test it and check and try to recreate
(25:43):
those So I see, like you have theories about what
happened before four hundred thousand years into the Big Bang,
and so you're trying to do small experiments that will
sort of confirm parts of that theory. So that didn't
you feel confident about using a theory to peer into
the Big Bang? Yeah, exactly. So it's extrapolating into what
we can't see, and then we're trying to test it
(26:05):
in the lab and said, like, let's see if our
theory works in similar conditions. So it's kind of like
a it's like math vision, you know, like we can't
technically see inside the sun, but we can see an
inside using math only put on my math goggles and
now I can see anything. Well, I guess, I mean
you could call a that applied math or math vision.
(26:25):
But yeah, I think we should rename all the applied
math departments around the country as math vision departments. Be
a math visionary. But the speaking of vision, there is
another way now to see into that plasma, to look inside,
and that's because we have a new way to look
out into the universe, and that's with gravitational waves, which
(26:46):
are only recently discovered. We can listen not to see.
Oh my god, I hate that analogy. We're not listening.
Gravitation waves don't make a sound, you know, They're just
waves like everything else. So it's you mean, like there's
stuff happening, but underneath that, like a rumble, you can
see sort of these waves coming out. Right. Well, what
(27:06):
I mean is that the hot plasma is is opaque
to photons, right, but it's not opaque to other things, right,
It's transparent to other things. It's transparent, for example, to
gravitational waves. So the current theory of what happened just
after the Big Bang, like ten to the minus thirty
five seconds after the universe was born, is that there
(27:27):
was a huge shock wave in space. Gravitational waves were
made just at the very very beginning of the universe,
and gravitational waves can pierce plasma, they can go through
anything because they are the shaking of space itself, right,
so nothing can block them. So those can pass through
that plasma. When those waves have dispersed out into the
infinity by now, when we have lost them by now, well,
(27:49):
it's just the same as with the photons from the
cosmic microwave background. If the Big Bang happened everywhere all
the time, then those waves were created everywhere and went
in every direction. If we want to see them now,
we just listen, you know, in some direction a long
long time ago, and they should be arriving now. Gravitation
always made super far away fourteen billion years ago, should
(28:10):
just be arriving on Earth now. And you're right, it's
very hard to see. It's like the whole room is reverberating, right,
kind of like, yeah, exactly, reverberberating. And the cool thing
is maybe you've heard this story, but you know, there's
a collaboration that had a telescope listening for these and
they thought they heard them. This is the bicep collaboration,
(28:32):
and they claimed the discovery and then it turned out
that it was just dust and they were actually totally
wrong and they had to walk back their discovery, which
is kind of embarrassing. Yeah, but you know, it happens
in science, right, Yeah, it totally happens, you know. Yeah,
it's they didn't do anything wrong. They just you know,
they claimed they discovered it. They made their best statement,
(28:52):
and then they learned more and they said oops. And
that's fine. That's the process of science. Um. But there
are ways to see those. We just haven't heard those
vitational waves yet, but people are working on it. One
day we'll find them. So those might tell us what
happened inside of the the really really baby universe, right yeah, exactly,
you know, the fetal universe or something, you know, and
(29:12):
just after it was born. And that would be fascinating
because we could learn a lot. First of all, if
we see them, that confirms that these gravitational waves were
made and that we think inflation probably happened, and that
would be incredible, right that would that would go from
math vision to like you know, I don't know, um,
math discovernment. That's the worst probably anyway, Yes, so we
(29:38):
could see very very early on and that would be cool. Um,
But we haven't heard those yet. People are working on it.
So how far how far into the Big bank could
we listen with these gravitational waves? Yeah, tend the minus
thirty five seconds after the Big Bang? Why not just
call that zero like it's so much happy because zero
and math. Put on your math goggles. There's a difference
(30:01):
between zero and tend of the minus thirty five. Although
I'll admit I don't even know what prefix goes before
that could have second or a yapto second or something.
What do you think it is? Um? I think it's
a sound second. I think it's a Jorge second channel
a second or something. It's a baby second because it's
(30:21):
because it's so tiny. No. Um. So that's a really
exciting way to probe the very very very early universe.
But wait, wait, where does that number come from? Tend
to the minus thirty five? That seems very like definitive. Oh,
there's a lot of uncertainty there, but it comes from
calculations about how inflation happened. You know. Inflation is the
process of the universe stretching really really fast just after
(30:44):
it was born. You go from a tiny microscopic dot
um or every tiny microscopic dot was then just stretched
out to a really big universe. The universe expanded by
a huge amount in a really tiny amount of time.
We should do a whole podcast on what is inflation? Sometimes, Um,
that's when inflation stopped. Yeah, but that's just it's an estimate,
and there are different theories of inflation. And you know,
(31:05):
it could be tend in the minus thirty six seconds
or tenda minus thirty two seconds. And but of course,
as you say, why isn't it ji zero? And we
love to see zero, and we'd love to see the
first moment when time was created. Did something happen at
ten to the minus thirty five that's when inflation stopped? Yeah? Yeah, So,
very very briefly, the history of the universe is the
(31:27):
universe is created somehow mysteriously totally unknown process, and then
it's stretched really really dramatically, really really quickly for about
ten of the minus thirty five seconds, right, and then
it's been expanding ever since. And then about five billion
years ago, I started stretching again, and that's what we
call dark energy. Oh I see, so you couldn't these
waves gravitational waves wouldn't tell you what happened when it
(31:49):
was stretching or before it stretched. Yeah, there's sort of
the results of the stretch. You know. It's like, oh,
if you jump onto a trampoline, you know, these are
the waves that moved through the trampoline. Inflation caused these waves.
It's like the bang of the Big Bang. It's the
bang just after the Big Bang, and you lived just
down the street from the Big Bang, and this is
(32:09):
what you hear, all right, So then, um, but then
who knows, how would we ever see what happened before?
I know, I'd love to see at zero, right or
even negative, like what happened before? What was there before
and what made the universe start? And that's it's hard
to imagine how we could ever see that, even see
before tend of the minus thirty five, to see what
was happening at zero and fierce that veil and go
(32:32):
through it and see what happened before. That's just the
realm of science fiction. It may literally be impossible. You know,
maybe that no information from before that was even preserved.
It's just like destroyed um in the Big Bang. We
don't even know. You don't think even math vision could
get us through. I mean, like, you know, like, could
we form a theory that just put on two math
(32:53):
goggles and right, what's the big deal? Uh? No, we
certainly could. And you know, this is an interesting question
of like can you even study that. Is this philosophy
or is this science? Can you talk seriously about what
happened before the Big Bang or what caused the Big Bang?
And people like to talk about crazy ideas like the
Big Bang was the result of the collisions of two
other universes and higher dimensions, and I mean, I know
(33:15):
it sounds like I just made up those words. I
don't mean anything, But that's a real theory. You mean, like,
could we talk about anything before there was anything? That's right? Yeah,
when there was nothing? Can we talk about something right?
That sounds like that bid in spaceballs or something? But
but yeah, and it's it's a reasonable question. And some
people say you can't it's just philosophy because we can
never test it. We can never know what happened because
(33:37):
we can never get any data that confirmed or denied
any of those theories. But other people say, you know,
you could. Sean Carroll, for example, he argues that you
can talk about what happened at a time or a
place you can never visit, because you can build theories
that extrapolate, as you were saying, using math vision into
that time, and you can confirm or deny those theories
in time and places that you can test, and you
(33:58):
can think about whether that extrapolation is valid and test
those in other ways. So it's indirect, but you know,
there are ways to talk about what might have happened.
Then it's just it would be hard to kind of
put your finger on it and really kind of see it,
especially because a time equal zero, your finger doesn't exist.
To put it anywhere does it be really hot? So
don't put your finger right now. People don't put your
(34:20):
finger on a big bang. Yes, So, you know, if
you look deep into the history of the universe, you
learned about how the Earth was made. You learned about
how the Solar system was formed, You learned about how
galaxies came together, You learned about how the universe is expanding.
You learned about the first stars. You go all the
way back to the very initial moments when the universe
(34:42):
became transparent, and that's you know, what we think about
when we think about the universe and you learn all
this rich history and it's told us so much about
who we are and uh and how everything works and
you know what's gonna happen. So it's it's pretty fascinating.
I love looking at the universe's baby picture. Yeah. Now,
there's a certain definitely comfort to know in your origins, right,
Like if you didn't know if you were born or
(35:03):
where you came from, it kind of tends to unseckle you, right, Like,
what is my place in the universe? It all could
just be a manufactured, you know, illusion from the creators
of the simulation that we're living in, right, So it
could all just be a lie. Yeah, but we're what
what were they like as a baby? Though? That's right,
it's a recursive question. But I totally agree with you.
(35:24):
It tells you something about who you are, and you
like to know that thing those things because it tells
you how to live your life. Right. If you know
where you came from, you have an idea of where
you're going and how to get there, and what's important,
what your place in the universe is, you know? Yeah,
and your place turns out is very small, almost nowhere,
pretty cold, cold, it's pretty cold. Yeah, but you should
(35:45):
still go on and live your life and be nice
to people. Yeah. If you still have a question after
listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us
at Facebook, Twitter, and Instagram at Daniel and Jorge That's
(36:08):
one Word, or email us at Feedback at Daniel and
Jorge dot com.
Sometimes it drives me crazy thinking about the secrets that
are buried in the past, you know, things that actually
happened that we just don't know the institude. You mean,
like who killed JFK. No, No, I'm thinking bigger, Like
where are my socks after I put them in the dryer?
That's a big mystery. But I'm thinking cosmic size mysteries.
(00:29):
I mean, like who thought two introverts could make his
science podcast? That's an enduring mystery for sure. But I'm
talking about like universe size mysteries, you know, like, you know,
the universe started in one way and no other way,
And what if we could just go back to the
past and watch it and and unearthed these mysteries from
the past. Wouldn't that be amazing? What was it like
(00:50):
as a baby? Basically? Right? Like, was it awkward? Cute? Funny? Tantramy? Hi,
(01:11):
I'm Jorge. I'm the creator of PhD Comics, and I'm Daniel.
I'm a particle physicist work at the Large Hadron Collider
smashing particles together. And this is our podcast Daniel and
Jorge Explain the Universe, where we trying to explain basically
everything in the universe. In a way that makes sense
to you everything the whole universe. Yeah, so to be
on the program, we have the question what did the
(01:37):
baby universe look like? That's right? What did the universe
look like when it was really young, when it was
just formed, or just after it got started to look
totally different from today? Did it look basically like today?
What did it look like? Daniel? What did you look
like as a baby? I looked like a universe as
a baby. Actually, oh good, that's better than me. I
(01:59):
looked really different as a Maybe then I do now
because I have one of these noses that grows sort
of tectonically. So when I was a kid, I had
a tiny, little button nose, and now I have sort
of a very large alpine nose that just continues to
grow through my lifetime. Well, that sounds better than me.
I just looked like an old bald man. Did you
look like Winston Churchill when you were born? I did
(02:20):
a little bit. Actually, my father was named after Winston Churchill,
which is which is a coincidence there. Okay, So the
question today is what can we learn about the universe
from its baby picture? What did the universe look like
as a baby? Yeah, this is an interesting question because
I was thinking the other day, you know, Daniel, how
do you know that you were actually born? Like, how
(02:41):
do you know that you were a baby? I mean
you think I came out this size? Yeah? Basically, right, Like,
how do you know how do you know you didn't
just pop into existence when you were five years old
or you know, like you were growing out of a
test tube and then and then um and then extra
rooted when you were five years old, which is when
(03:02):
sort of your memories start to kick in. Right, extruded.
That sounds like such a pleasant experience. I wasn't born,
I was extruded. Technically we're all extruded. Yeah, but you're
you're right. There's a there's a sort of a larger
question there, which is like how do you know about
yourself and your context and where you came from? And
why is that important? Right? Like I might say to you, like,
(03:23):
I don't know if I was born, you know, at ten,
out of the laboratory and implanted with all these memories
to make it feel like I had a childhood, But
what does it matter? Right? You might say that it
doesn't matter, but I think it does matter. I think
it matters where we come from, what our context is,
what our culture is. In the same way we wonder
about larger things like how is the Earth made? Right?
(03:44):
The Earth's baby picture looked like, how is the Earth extruded? Yeah,
I guess I'm talking about like evidence, you know, Like, um,
it's nice that I have there are pictures of me,
or at least that I'm told it's me as a baby,
so I can sort of trace my development. But if
I didn't have those pictures, I might wonder did I
just pop into existence when I was five? Right? And
(04:05):
you can look at those pictures, and you can see
things about yourself that, you know that tell you something
about who you are, like to your old Jorges already
holding a banana or already cracking silly jokes or you know,
doodling on the wall or something. Their truths about you
that are emerged early on. Right, Like, man, look at
that cute baby. I can only imagine what the baby
(04:25):
is going to grow up to be, Like, how did
such a cute baby turn into this? You know, there's
the mystery, right, there's awesome, magnificent specimen. Yeah, And I
think that every time, for example, I see like an
old time picture of my hometown. You know, I grew
up in Los Almos, and they're all these pictures of
what it looked like during World War Two, and you
know that shaped the history of the town. And when
I see these old pictures, I like saying, like, oh,
(04:46):
look that building, I still recognize that it's an enduring feature.
And all this is destroyed, it was just transient. So
in the same way, I like thinking about the history
of the universe because it teaches us something about how
it was all put together, and you know what it all.
You see things that make it and what it is
like unique, make it, yeah, exactly special. Yeah, And it
(05:07):
tells us a lot about what's happening in the future.
You know, we want to know what's going to happen
to the future because we're invested, we're going to live
in it. Then we better look into the past. And
you know, we've made startling discoveries by doing this. You know,
the whole discovery of dark energy, the fact that the
universe is being shredded apart by some massive, not understood energy,
right that was only discovered by looking into the past
and understanding what the universe used to look like. Right, yeah,
(05:29):
baby talk aside, we're talking about the universe, right, and
how can we tell what the universe was like, you know,
not just a hundred years ago, two thousand years ago,
but fourteen billion years ago? Yeah, exactly what did it
look like? And what can we learn from that? So,
as usually, we were curused to hear what people out
there thought about this question, and so here's what they
(05:50):
had to say. What do you think the early universe
looked like? Um, the baby universe I would think would
be something really compactly dnce in like probably in a
circular looking thing. I would think, yeah, um, probably nothing
(06:11):
in particular, just a bunch of gases and like crazy,
maybe spirals. I don't know, like you know, not no
stars or anything, that's for sure. I guess like a
more extreme version of what it looks like now because
everything was kind of more close even though it's expanding,
so it's like, I know, there was less space in
between everything, So I guess more bright and intense. I guess. Delete.
(06:38):
On the program, we have astrophysicist Katie mac Hi. Katie, Hi,
how are you good? So you're probably one of the
most famous astrophysicists on the internet. Do you have a
huge Twitter following, and uh, that's really cool. Thanks. Yeah,
it's been really interesting. I don't know where all the
people come from, but I'm glad that they are hanging
out and listening to me talk about astrophysics. Can you
(07:01):
tell us a little bit about where you work. I'm
in the physics department at North Carolina State. I'm an
assistant professor, and I'm also part of the Leadership in
Public Science Cluster, which is a new initiative to encourage
connection between scientists and the general public. Very cool. Yeah,
And I think it's important for people that people to
understand that you're not just somebody on Twitter who likes
(07:23):
to talk about science, but you're actually a practicing scientist
who's chipping away at the mysteries of the universe. Yeah.
I'm doing the best I can at that. And your
expertise is in um Yeah, So I do theoretical cosmology,
which is the study of the universe from start to
finish and the evolution of the universe and what's in it.
And my area of specialty at the moment is dark matter.
(07:45):
So I'm interested in what dark matter is and how
it did what it did in the early universe and
all of that, and I'm also interested in black holes
and in the very early universe and the very end
of the universe. What did you think about people's general
knowledge of what the early universe is like? This surprise you.
I think everybody kind of gets the idea that it
(08:07):
was real, different than now and maybe not as structured um,
and that the structure in the universe has come about
over time, which is true. And so help the people
out there understand that. How can we possibly know that?
How do we know what the early universe looked like
at all? We know what the early universe looks like
because we can look right at it. We can actually
see it. We can watch the Big Bang happening. And
(08:27):
there's caveats to that in terms of what I mean
when I say a big bang and what I mean,
but when I say watch it happened. But the nature
of the early universe is one of the most certain
things we we have in cosmology because we can actually
see it directly. So tell us what that means. Where
do you look to see the Big Bang? Well, you
look everywhere? Um, okay, so let me go back a
(08:49):
couple of steps, billion steps. Yeah, yeah, yeah, Why do
we even think there was a big bang? There was
one guy who we talked to without the universe is
like this forever. How do we know that's not true? Right?
We know that the universe is changing with time because
we can see that it's expanding UM. And the way
we see it's expanding is that we look at really
distant galaxies and we see that they all seem to
(09:09):
be moving away from us. The whole universe is getting bigger,
and so the spaces between all of the galaxies is
getting bigger, and that means that every galaxy we see
is going to look like it's moving away from us.
And in fact, the more distant galaxy, the more quickly
it seems to be moving away from us. And so
you know, beyond a certain distance UM, when we get
(09:31):
out into like the open universe, outside of our little
local area, everything is moving apart. And that only makes
sense if the universe is expanding, and if it's expanding
like the same in every direction. So you can look
at that and then you can say, well, if it's
getting bigger than it was smaller in the past, and
you can just kind of extrapolate back and say that
(09:52):
there had to have been a time when everything was
really really really close together. But that's sort of the
question is like, what did things look like when they
were are all sort of on top of each other,
when the universe was that small? How do we know
what it sort of looked like. If you have some
kind of box with stuff in it, and then you
make that box bigger than things get farther apart, it's
sort of cools down because there's there's more space and
(10:15):
things are not bumping into each other as much. And
so if you go the other direction, then the early
universe should have been a lot hotter and denser and
you know, in some sense sort of smaller than it
is now. And so because of that sort of extrapolation,
a bunch of physicists um back in the day said, well,
if that's the case, then all of that heat and
(10:37):
radiation from the early universe should actually still be out
there somewhere. Well why should it still be out there?
I mean, wouldn't it have been absorbed or bounced around?
Since then? What do you mean all that heat and radiation? Okay,
so so this is where it gets a little bit
trippy and complicated, But this is where it also gets
really cool. I love trippy and complicated, but it's really
(10:58):
cool because this is this is where we're actually seeing
the Big Bang. Okay, so the speed of light is
not infinite, which means that if you look at like
the nearest star other than the Sun, you're looking at
something that's four light years away roughly. That means that
the light that you see from that star is four
years old by the time it gets to you. So
you're saying that to look into the past, you just
(11:19):
have to look at things that are far away. Yeah, yeah, exactly,
And so the farther away that you look, the farther
in the past you're seeing. And we have telescopes where
we can see galaxies where the light has been traveling
for like thirteen billion years, you know, So we can
actually see galaxies that are like some of the first
galaxies ever formed in the universe. We can see really
(11:40):
really early objects. If we just keep looking farther and
farther away, then we're looking farther and farther back, and
we're looking at a time when the universe was so
hot and so dense that that part of the universe
was on fire. Every part of the universe was like
this sort of giant fireball. I mean, not are exactly,
(12:00):
but like plasma, right, And so there's some part of
the universe that's so far away that the last like
a little bit of radiation from that fire has been
sort of streaming through the universe just in every direction.
And there's a part of the university so far away
that that little bit of radiation from that fire has
(12:21):
been traveling through the universe and is just reaching us. Now,
that's awesome, And I think the really mind blowing thing
about that is that it comes from every direction. Like,
as you're saying, you look out into the universe, you
look at something that's the age of the universe away.
You're seeing something that was really far away a long
time ago. Now you look at the opposite direction, you're
seeing something which was the other side of the universe
(12:43):
when it was born. Hold On, I have so many
questions for you. But before we keep going, let's take
a short break. Let me change back off a second.
(13:03):
I'm still a little bit confused. Um, So what you're
saying is that you know, there's there are the galaxies
that are the furthest that we can see. Yeah, but
you're saying, like if we point our telescope just to
the right of that oldest galaxy into literally like black nothingness.
Anything we get when we point our telescopes to that
black spot sort of must be as old as the universe.
(13:24):
Like if we see it in an optical telescope, then
we're probably saying something else. But just to the right
of that old old galaxy, there's radiation coming from that
point that has not hit anything until it's hit us.
Then that's been traveling for like thirteen point eight ish
billion years from a time when the universe was only
(13:46):
about years old. Oh, I see, but it somehow ended
up there and then it had to make its way
to us. Well, it was everywhere, I mean, every part
of the universe put out radiation at that time. Like
the universe is this like fireball kind of state, and
the whole universe is cooling at the same time, right,
and so you have the gas is cooling down, and
(14:07):
there's this radiation that's traveling in every direction. That's like
escaping from the time when the whole universe is on fire,
and that light goes in every direction. So if we
look in one direction and we're seeing the early universe,
and then we look in another direction. We're not seeing
the same part of the early universe, right, right, right,
We're seeing different parts of the early universe. But you
(14:29):
have to think of time in a kind of geometric
way for this to make sense, right, So I kind
of like to think of like we have these like
spherical shells of time around us. Okay, so yeah, yeah,
imagine you have your your head is inside this sphere
one ft in radius that's a nanosecond in the past,
and then you know, you build another sphere that's two
(14:50):
nano seconds in the past, and then you build a
sphere that's you know, a light year in radius, and
then you're that's your one one year ago sphere, and
then you just kind of keep going. So you have
these sort of nested spheres of deeper and deeper time.
And at the very end of that, the largest sphere
is the observable universe, and that sphere is this fireball universe.
(15:15):
So you're saying the universe when it was really young
looked like a fireball. Yeah, I mean every part of
it was was plasma. What does that mean, like a
cloud like a gas. Yeah, it was too hot for
Adams to be neutral, so it was protons and electrons
flying around and radiation, so it would have looked like
a fire in the sense that it was just glowing
(15:36):
hot and then over time it's cooled down. So you
wouldn't want to be around in the early universe. No,
it would not be safe. The dangerous baby. Yes, yes,
definitely if you get into like even earlier times, like
the first few seconds and before, like it's like nuclear
reactions in every point of space at all times. You
(15:56):
know it's bad. It gets real bad you go earlier
and there there in the universe. So it was such
a hot mass of soup soupy mess that nothing could
even form. And so that you're saying that fireball um expanded,
that's the big bang, and it dissipated, but we're still
sort of seeing kind of the afterglow of it. Yeah,
(16:17):
And I don't want to I don't want to imply
that the universe was like an expanding sphere, because it
might just be infinite in every direction and not really
have like a shape to it per se. It might
be infinitely huge. We don't know. We don't know for sure,
but but the idea I guess is that you know,
when people go outside and night or even during the day,
(16:39):
they're getting an image of the baby Universe when they
look up. That kind of the idea if they could
see in the microwave spectrum, then yeah, they'd get a
little bit of that sort of glow from the early universe.
It turns out if you if you have one of
those old TVs that picks up broadcast, you know, not
not the digital kind. Little bit of the static on
(17:01):
those things is is the afterglow of the Big Bang,
the cosmic microwave background. So you can actually see the
Big Bang in the snow on old televisions. But but
the picture of the baby Universe is not like snow.
It's not um like a glow or noise. It actually
has like a it's a picture right like it. It's
got a specific texture on it, right yeah. Yeah, So
(17:21):
we can map it out. If we take these microwave
telescopes and look at every point on the sky and
map out the microwave radiation, then we can see where
some points were a little bit hotter than others, and
you can see kind of these patterns of little splotches
for hotter and colder spots on the you know, background
(17:44):
light and the background light. You know, it looks like
a sphere around us, just like if you were in
a planetarium, you'd see, you know, um, the stars and
a sphere around you. And we can look at those
patterns and figure out where, like there was a little
bit more matter in a spot, a little bit less
matter in that spot. And we can see traces of
(18:05):
like sound waves traveling through the early sort of fireball universe,
because it turns out when the universe is that dense,
sound can travel through space. Yeah. Yeah, so the early
universe was like ringing with sound waves and you can
see those in the picture. Yeah, you can see, um,
you can see like patterns associated with like sound waves
(18:27):
traveling through the sort of plasma. So it wasn't just
a hot mess. It was a hot, noisy mess. Yeah.
It sounds a lot like my house on a Saturday afternoon.
Yeah yeah, kind of like real babies, Yeah, exactly, kind
of like a baby hordhead. There you go. So, um,
are you're talking about this very early universe and things
(18:47):
we can learn about how what it meant? And so
what might you learn about the early universe, Like what
kind of result could you get about the early universe
that would surprise you or make you feel differently about
like your life and our rule here in the whole context.
What kind of is could you could you learn that
would change your feeling about, you know, the human experience,
how our universe came to be and why it is
(19:07):
the way it is. That would be really exciting to
find out. There could be other universes that may have
like collided with our universe at early times, and there
are ways to look for evidence of that with the
couse of microwave background, and if that happened, that would
be really interesting to see. And one of the possibilities
for that is that the Big Bang happened because two
(19:30):
universes kind of collided in the past and bounced off
each other, and so there could be like this parallel
universe out there that we might be doomed to collide
with again twins, So that would be really interesting as
well to know that, like there's more spatial dimensions that
we can see, so you know, the universe is kind
of bigger in some direction that we don't understand, So
that would be really interesting. That's amazing. Would it shock
(19:52):
you if fourteen billion years from now people could still
see your baby picture I was such an ugly baby.
The analogy really works because you can look back at kids,
for example, when there were two or three, and you
can see in them the seeds of their current personality.
You can see, oh, it was a fighter, it was
a screamer, a curious baby. So I think there are
(20:14):
truths about us that are hidden in our baby pictures,
the same way our truths about the universe that are
secreted away in the in the cosmic bac away background. Well,
thank you so much, Katie for joining us. It's good
to chat about the the universe. I'm always happy to
do that. Yeah, you're welcome any back, anytime, and people
can find you on Twitter, right, Katie, your your handle
is at a stro Katie. One word right A S
(20:37):
T R O K A T I E. Great, Yes,
that's right. Well, thank you so much for joining us, Katie.
I hear you're working on a really great project these days.
A new book. Yeah, I'm working on my first book.
It's for general audiences, so um, you know, not not technical,
but the topic is the end of the universe, So
where it's all going to go, how it's all gonna end, um,
(21:00):
what that's going to look like. What it means for
the universe to have an end um It's it's should
be really fun. It's called the End of Everything, and
it'll be out in hopefully before the end of the universe. Yeah,
it would be really inconvenient if the universe ended before
the book came out. So I'm crossing my fingers and
hopefully will have a happy ending or is it a
(21:22):
spoiler alert? There aren't very many pleasant ways to destroy
the entire cosmos. This is not a Disney book or hey,
unfortunately great, So I hope everyone checks it out and
keeps an eye for it. Thank you, Katie. Thanks, So
(21:47):
that was really fascinating. Katie told us a lot about
how we can see the history of the universe from
these really really old photons that are come from deep
in space and deep back in time, all the way
back to four hundred thousand years after the Big Bang. Yeah,
when the universe became transparent. That's an interesting constant, right,
Like we think of space is black and full of
(22:09):
stuff in it, but relatively speaking, it's kind of transparent, right,
it's empty, Yeah, which is fantastic. Right. It's good luck
because if the universe was not transparent, we couldn't have
learned all these amazing things we learned about the universe, right,
And you might think, well, of course space is transparent,
but that's the thing, it wasn't always right. Around four
hundred thousand years after the Big Bang is the first
(22:30):
time that it cooled down enough that the hot plasma
Kittie was talking about moved from being ions into being
neutral atoms so that photons could fly through them unimpeded. Right,
So it makes me wonder, what was it? How could
we ever see before that? Can we see before four
hundred thousand years after the Big Bang? We can, but
we can't use photons. You know. It's like staring at
(22:52):
the Sun. Right, you can see the surface of the
Sun because it's shooting our photons, But you can't see
photons from the inside of the Sun because those get absorbed.
And so looking at the earlier history of the universe
requires somehow looking inside this big ball of plasma, and
we can't do that with photons, but looking sort of
in time, right, we want to pierce into it in time,
(23:12):
that's right, And so we can't see directly. One thing
we can do is that we can do experiments to
recreate it. You know, we can say, well, what was
it like when there was so much energy focused in
one place? You mean, we can make babies in a
test tube. I'm not proposing that you and I make
babies in a test before, as much as that would
be on the frontiers of science. And also I think
it's sort of inappropriate to raise that like on air
(23:34):
in the podcast. I mean that should be a private conversation.
You're like buying me a glass of wine. At least
for as Joe, I'm not that easy. Um, we can
recreate the conditions of the Big Bang sort of, um,
just by smashing particles together, so you know, the large
Hadron collider, we smash protons together. Sometimes we even smash
(23:55):
heavier stuff together like lead or gold nuclei and try
to recreate the big hot mess that was that ball
of plasma, just to see what was it like and
what's the physics of it and what happens. So what
do you mean, recreate the conditions like the temperature or
just like the crazy the pure energy nous of it. Yeah,
the density of energy, right, that's essentially what temperature is
(24:16):
in my in my understanding. You know, we're just trying
to create a lot of energy into in one place,
so that quirks, for example, which usually are bound tightly together,
can feel free because there's so much energy around that.
Everybody has so much energy, they don't they don't get
tied down. You're like, be free, quargs, be free, take
off your foes. It's the Cork Liberation Front is whatever.
(24:39):
The Q left is sort of a militant group there. Um. Yeah,
so you can sort of think of the LHC is
like a big bang machine. You know, every time we
collid were like recreating these collisions and so we can
study that experiment. Makes me a little nervous that, Daniel,
just like, what's what's the big deal? Because me like
a big bang machine. First of all, it sounds kind
of it sounds a little inappropriate. But like you made
(25:01):
a machine that makes the universes. That's a that's a
little worrying, isn't it. Well, it only makes forty million
universes a second, what what could go wrong? No, seriously,
people don't worry. We're not We're not creating universes at daily. See,
we're creating the We're recreating the conditions of the early
universe by making something that's as hot and dense in
(25:21):
a very small space, and we're all wearing life jackets
and hard hats and nobody should be concerned and diversion. Yeah,
and the point is that what we're just trying to
study it, and because we have these theoretical models that say,
we think we know what happened before four thousand years
after the Big Bang, that's the last thing we can
directly see. We think we know what happened before that,
so let's test it and check and try to recreate
(25:43):
those So I see, like you have theories about what
happened before four hundred thousand years into the Big Bang,
and so you're trying to do small experiments that will
sort of confirm parts of that theory. So that didn't
you feel confident about using a theory to peer into
the Big Bang? Yeah, exactly. So it's extrapolating into what
we can't see, and then we're trying to test it
(26:05):
in the lab and said, like, let's see if our
theory works in similar conditions. So it's kind of like
a it's like math vision, you know, like we can't
technically see inside the sun, but we can see an
inside using math only put on my math goggles and
now I can see anything. Well, I guess, I mean
you could call a that applied math or math vision.
(26:25):
But yeah, I think we should rename all the applied
math departments around the country as math vision departments. Be
a math visionary. But the speaking of vision, there is
another way now to see into that plasma, to look inside,
and that's because we have a new way to look
out into the universe, and that's with gravitational waves, which
(26:46):
are only recently discovered. We can listen not to see.
Oh my god, I hate that analogy. We're not listening.
Gravitation waves don't make a sound, you know, They're just
waves like everything else. So it's you mean, like there's
stuff happening, but underneath that, like a rumble, you can
see sort of these waves coming out. Right. Well, what
(27:06):
I mean is that the hot plasma is is opaque
to photons, right, but it's not opaque to other things, right,
It's transparent to other things. It's transparent, for example, to
gravitational waves. So the current theory of what happened just
after the Big Bang, like ten to the minus thirty
five seconds after the universe was born, is that there
(27:27):
was a huge shock wave in space. Gravitational waves were
made just at the very very beginning of the universe,
and gravitational waves can pierce plasma, they can go through
anything because they are the shaking of space itself, right,
so nothing can block them. So those can pass through
that plasma. When those waves have dispersed out into the
infinity by now, when we have lost them by now, well,
(27:49):
it's just the same as with the photons from the
cosmic microwave background. If the Big Bang happened everywhere all
the time, then those waves were created everywhere and went
in every direction. If we want to see them now,
we just listen, you know, in some direction a long
long time ago, and they should be arriving now. Gravitation
always made super far away fourteen billion years ago, should
(28:10):
just be arriving on Earth now. And you're right, it's
very hard to see. It's like the whole room is reverberating, right,
kind of like, yeah, exactly, reverberberating. And the cool thing
is maybe you've heard this story, but you know, there's
a collaboration that had a telescope listening for these and
they thought they heard them. This is the bicep collaboration,
(28:32):
and they claimed the discovery and then it turned out
that it was just dust and they were actually totally
wrong and they had to walk back their discovery, which
is kind of embarrassing. Yeah, but you know, it happens
in science, right, Yeah, it totally happens, you know. Yeah,
it's they didn't do anything wrong. They just you know,
they claimed they discovered it. They made their best statement,
(28:52):
and then they learned more and they said oops. And
that's fine. That's the process of science. Um. But there
are ways to see those. We just haven't heard those
vitational waves yet, but people are working on it. One
day we'll find them. So those might tell us what
happened inside of the the really really baby universe, right yeah, exactly,
you know, the fetal universe or something, you know, and
(29:12):
just after it was born. And that would be fascinating
because we could learn a lot. First of all, if
we see them, that confirms that these gravitational waves were
made and that we think inflation probably happened, and that
would be incredible, right that would that would go from
math vision to like you know, I don't know, um,
math discovernment. That's the worst probably anyway, Yes, so we
(29:38):
could see very very early on and that would be cool. Um,
But we haven't heard those yet. People are working on it.
So how far how far into the Big bank could
we listen with these gravitational waves? Yeah, tend the minus
thirty five seconds after the Big Bang? Why not just
call that zero like it's so much happy because zero
and math. Put on your math goggles. There's a difference
(30:01):
between zero and tend of the minus thirty five. Although
I'll admit I don't even know what prefix goes before
that could have second or a yapto second or something.
What do you think it is? Um? I think it's
a sound second. I think it's a Jorge second channel
a second or something. It's a baby second because it's
(30:21):
because it's so tiny. No. Um. So that's a really
exciting way to probe the very very very early universe.
But wait, wait, where does that number come from? Tend
to the minus thirty five? That seems very like definitive. Oh,
there's a lot of uncertainty there, but it comes from
calculations about how inflation happened. You know. Inflation is the
process of the universe stretching really really fast just after
(30:44):
it was born. You go from a tiny microscopic dot
um or every tiny microscopic dot was then just stretched
out to a really big universe. The universe expanded by
a huge amount in a really tiny amount of time.
We should do a whole podcast on what is inflation? Sometimes, Um,
that's when inflation stopped. Yeah, but that's just it's an estimate,
and there are different theories of inflation. And you know,
(31:05):
it could be tend in the minus thirty six seconds
or tenda minus thirty two seconds. And but of course,
as you say, why isn't it ji zero? And we
love to see zero, and we'd love to see the
first moment when time was created. Did something happen at
ten to the minus thirty five that's when inflation stopped? Yeah? Yeah, So,
very very briefly, the history of the universe is the
(31:27):
universe is created somehow mysteriously totally unknown process, and then
it's stretched really really dramatically, really really quickly for about
ten of the minus thirty five seconds, right, and then
it's been expanding ever since. And then about five billion
years ago, I started stretching again, and that's what we
call dark energy. Oh I see, so you couldn't these
waves gravitational waves wouldn't tell you what happened when it
(31:49):
was stretching or before it stretched. Yeah, there's sort of
the results of the stretch. You know. It's like, oh,
if you jump onto a trampoline, you know, these are
the waves that moved through the trampoline. Inflation caused these waves.
It's like the bang of the Big Bang. It's the
bang just after the Big Bang, and you lived just
down the street from the Big Bang, and this is
(32:09):
what you hear, all right, So then, um, but then
who knows, how would we ever see what happened before?
I know, I'd love to see at zero, right or
even negative, like what happened before? What was there before
and what made the universe start? And that's it's hard
to imagine how we could ever see that, even see
before tend of the minus thirty five, to see what
was happening at zero and fierce that veil and go
(32:32):
through it and see what happened before. That's just the
realm of science fiction. It may literally be impossible. You know,
maybe that no information from before that was even preserved.
It's just like destroyed um in the Big Bang. We
don't even know. You don't think even math vision could
get us through. I mean, like, you know, like, could
we form a theory that just put on two math
(32:53):
goggles and right, what's the big deal? Uh? No, we
certainly could. And you know, this is an interesting question
of like can you even study that. Is this philosophy
or is this science? Can you talk seriously about what
happened before the Big Bang or what caused the Big Bang?
And people like to talk about crazy ideas like the
Big Bang was the result of the collisions of two
other universes and higher dimensions, and I mean, I know
(33:15):
it sounds like I just made up those words. I
don't mean anything, But that's a real theory. You mean, like,
could we talk about anything before there was anything? That's right? Yeah,
when there was nothing? Can we talk about something right?
That sounds like that bid in spaceballs or something? But
but yeah, and it's it's a reasonable question. And some
people say you can't it's just philosophy because we can
never test it. We can never know what happened because
(33:37):
we can never get any data that confirmed or denied
any of those theories. But other people say, you know,
you could. Sean Carroll, for example, he argues that you
can talk about what happened at a time or a
place you can never visit, because you can build theories
that extrapolate, as you were saying, using math vision into
that time, and you can confirm or deny those theories
in time and places that you can test, and you
(33:58):
can think about whether that extrapolation is valid and test
those in other ways. So it's indirect, but you know,
there are ways to talk about what might have happened.
Then it's just it would be hard to kind of
put your finger on it and really kind of see it,
especially because a time equal zero, your finger doesn't exist.
To put it anywhere does it be really hot? So
don't put your finger right now. People don't put your
(34:20):
finger on a big bang. Yes, So, you know, if
you look deep into the history of the universe, you
learned about how the Earth was made. You learned about
how the Solar system was formed, You learned about how
galaxies came together, You learned about how the universe is expanding.
You learned about the first stars. You go all the
way back to the very initial moments when the universe
(34:42):
became transparent, and that's you know, what we think about
when we think about the universe and you learn all
this rich history and it's told us so much about
who we are and uh and how everything works and
you know what's gonna happen. So it's it's pretty fascinating.
I love looking at the universe's baby picture. Yeah. Now,
there's a certain definitely comfort to know in your origins, right,
Like if you didn't know if you were born or
(35:03):
where you came from, it kind of tends to unseckle you, right, Like,
what is my place in the universe? It all could
just be a manufactured, you know, illusion from the creators
of the simulation that we're living in, right, So it
could all just be a lie. Yeah, but we're what
what were they like as a baby? Though? That's right,
it's a recursive question. But I totally agree with you.
(35:24):
It tells you something about who you are, and you
like to know that thing those things because it tells
you how to live your life. Right. If you know
where you came from, you have an idea of where
you're going and how to get there, and what's important,
what your place in the universe is, you know? Yeah,
and your place turns out is very small, almost nowhere,
pretty cold, cold, it's pretty cold. Yeah, but you should
(35:45):
still go on and live your life and be nice
to people. Yeah. If you still have a question after
listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us
at Facebook, Twitter, and Instagram at Daniel and Jorge That's
(36:08):
one Word, or email us at Feedback at Daniel and
Jorge dot com.
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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