Listener Questions 2.0

Join Daniel and Jorge as they respond to 4 questions from listeners, just like you!

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Episode Transcript

Speaker 1 (00:07):
Hey, or hey. You know how we end most of
our podcast episodes by asking people to submit questions? Yeah,
people actually submit questions. Yeah? Do you know that a
lot of people actually right in? And how how are
the questions? Oh? My god? The questions are awesome. They
reflect like people's real desire to understand things about the universe. Well,

(00:27):
you read all of them, you know. I'll admit I
love the questions so much that I actually read and
answer all of them. But some of the questions are
so fun, and I think other people probably share the
same questions that I'll ask those people to record themselves
asking the question and send it in so we can
do a whole podcast episode just about some listener questions.

(00:48):
So somebody could write asking why they couldn't understand this episode,
not if we do a good job explaining it. What's that?
What kind of question would you have? Daniel viewer? A listener?
If I was sit into my own podcast, I would
be like, who is that guy with my voice? And
how did he get a podcast? What question would you ask?
I would probably ask, how do we get more people

(01:09):
to listen to this podcast? Hey, I'm je and I'm Daniel,

(01:32):
and welcome to our podcast, Daniel and Jorge Explain the
Universe or more accurvely, Today, Daniel and Jorge answer questions
about the universe that's right or explain the Universe inside
your mind that's right. Every week, twice a week, we
are beaming information and explanations about the incredible mystery that

(01:53):
at the universe straight through your ears and into your brain,
and we try to make it fun. We try to
make it engaging. We try to make sure that you
can actually understand what we're talking about. We don't want
to impress you with fancy words. We want to impress
you with the incredible majesty and wonder that is this
universe we find ourselves in. Yeah, and sometimes you know,
we don't get all the information out there are some

(02:14):
people don't quite understand everything that we covered and we
were able to cover in the podcast, and so people
still have questions. Yeah, Or sometimes we'll explain one thing
and it inspires another question, makes somebody wonder what about
this or what about that? And often I think Jorge
does an amazing job of anticipating those questions. A lot
of people have written in saying Jorge asks the questions

(02:36):
I have in my mind. So kudos to you, Jorge
or the great follow ups and for asking the right questions.
But that feels like it feels like a backhanded compliment. No,
it's not a backhand at all. It's a great compliment.
You're a good science communicator. You understand what is clear
and what is not um But sometimes there's a question
rattling around in somebody's head that they just really need

(02:57):
an answer to, and so they write in and ask us. Yeah,
so today on the podcast will be answering listener questions.
That means questions from people like you. If you're listening
to this and you have questions, you could hear your
own voice next time right to us at questions at
Daniel and Jorge dot com with your questions about the

(03:20):
universe or life or whatever is going on around you.
Or you can also reach out to us on Twitter, Instagram,
or Facebook. Right, you check all of those, right, Daniel,
I do. I respond to Twitter questions and Facebook questions
and all that kind of stuff. So, yeah, engage with us.
We're eager to hear from you. Yeah, you can ask
us about the universe, about how rude we are, how

(03:43):
engaging we are to each other, what our favorite fruit
is everybody knows. Nobody has a question about what your
favorite fruit is for her right now? Everybody knows it's papaya,
is clearly. Um, I feel like I don't know you, Daniel.
I feel like you don't know me. I think I
think bananas are clearly your favorite fruit. But I wonder, like,
is that the favorite fruit to say? I mean to eat? Sure,

(04:04):
but what about saying like, isn't papaya more fun word
than banana? More fun than banana? Yeah? Just fun about
the word papaya. I think you need to go out
into the street and ask people this question. No, here's
another question. What's your favorite fruit to draw? Like as
a cartoonists fun fruit to draw because papa is just
kind of a blob. I feel like if I say banana,

(04:26):
people are going to infer something from that that's a
dangerous Or if I say papaya, people might also infer
something from that. So let's just stay clear out of
cartooning plus fruits. Alright, alright, too bad. Well I'm still curious.
You can tell me offline later. Well, so today we're

(04:46):
gonna be answering four questions from all over the universe
or at least all over the planet Earth. That's right.
And so here's the first question. It comes from Alessandra
from Italy and he wants to know about how we
see so far in to space. Hi, guys, it's Alissando
from Italy. I really enjoy your podcast and encourious to

(05:06):
know how can we see so far through the space
without being hidden by thus nebula? Thank you and I
will enjoy your answer. Well, Alessandro certainly sounds Italian. He
didn't have to tell us where he was from. He um. Yeah,
he's a beautiful accent. It is the language of love
or is that French? Although I feel like Italian shouldn't

(05:30):
just be heard, it should be seen. Right, there's a
I'm sure there's some hand gestures that he couldn't capture
in that in that audio file. Save it for the
YouTube podcast. That's right, that's right. But it's a great question. Yeah,
it's an interesting question. How can we see so far
out through space without being obscured or blocked by nebula

(05:51):
and other clouds of dust and stuff that's out there.
How is it thevorable to see these stars are billions
and billions of light years away without anything blocking our view. Yeah, Like,
is it lucky that we can see so far? Is
the coincidence? You know? Is there some reason for it? Um?
I think first, let's just take a moment to appreciate
that view. You know, we say, like if you stand

(06:13):
on the top of the mountain and you can see
hundreds of miles, it seems like a great view. But
we don't often realize or consider the fact that the
view above our heads, the ones out into the night sky,
is the best view we will ever see. You know,
it's sort of it can give you vertigo just to
imagine that you're standing on the tip of a rock,
you know, that rock being Earth, and staring out billions
of miles across this ocean of space to these other

(06:35):
tiny little pin pricks. So it's really pretty incredible, not
just the space is vast, but that you can see
so far through it, right right, Yeah, Because like if
you stand up top mountain, you can't um see out
there forever. Right, Like, if you look at the next mountain,
it's going to look a little bit hazy, and if
you look at the mountain behind it, it's gonna look
even hazier. And so I think the question is how
is it that we can see with such crystal clarity

(06:58):
out there into space? And it's a great question, and
you know the answer is that mostly space is transparent, right,
transparent to light because what mostly what we're doing is
we're seeing with light, and so light can pass through
space without interacting, and that's what we mean by being transparent.
We mean that a particle like a photon, a piece

(07:18):
of light, can fly through it without being affected, without
being changed. So it's not that I mean there is
stuff out there. It's not like space is completely empty,
but you're saying that we can see really far because
the stuff that's there doesn't necessarily block the light. That's right, exactly.
Transparent doesn't mean non existent. Right, There is stuff out

(07:39):
there in space, but mostly the light can pass through it,
just the way the light can pass through the window
in your living room, right, mostly unaffected. Um, Now, the
window is not completely transparent, just like as you said,
the air is not completely transparent, but it's mostly transparent,
and so there can be stuff there. But as long
as the particles don't interact, then they fly through and
you can observe them on the other side basically unchanged. Okay,

(08:01):
So but what's out there in space that could be
blocking or a view, But isn't it. Yeah, and so
there actually are some things that block our view. Um.
So mostly spaces is empty, you know, from the point
of view of light, like, there's just nothing there. They're
little particles, um, But mostly it's empty. And the reason
that we can see light from other stars is that
there just isn't much stuff between us and them. But
sometimes that's not true. So for example, closer to the

(08:24):
center of the galaxy, there are these really big nebulas
of gas and dust, and we can't see through them
with normal light, the kind of visible light that we're
used to seeing with our eyes. And so, for example,
if you want to study the center of the galaxy,
you have to find other ways to do it because
you can't see it with visible light. Oh I see.
So the dust and gas out there do block our view,

(08:45):
but most of it is concentrated in certain spots, like
the center of galaxies. Yeah, exactly. And so if you
want to look out, you know, away from the center
of the galaxy to nearby stars, there's not a whole
lot between us and them. The thing that mostly blocks
your view is our atmosphere. Right, our atmosphere and fears
with light, and that's probably most of the stuff that's
going to do that. That's why we sometimes launch telescopes

(09:05):
into space so we can get a clear view of
what's coming at us from far far away. So if
the Earth just happened to be like like, if our
Solar system just happened to be inside of a nebula,
we would be totally blind to the outside universe. Yeah,
that's right. If we happen to be embedded inside a
gas cloud or dust cloud, absolutely, and remember our son
probably was born in a gas cloud or dust cloud.

(09:27):
Most of those places are stellar nurseries, those where stars
are born and eventually though, all that stuff coalesces, and
it doesn't just hang out of coalesces into stars and planets.
And that's you know, the ancient history of of our
Solar system. So we really are sort of lucky to
have such a good view, right because we could have
been born in like we are planet, could have been
in the in the middle of a coln of Los Angeles, right, Yeah,

(09:53):
we could be. But I think that most of the
time gravity will do its job and by the time
the planets are formed in life is evolved, etcetera. That
gravity will have done his job and cleared out that
space will pull it together into other objects, you know,
planets and stars or whatever. Oh, it concentrates all the gas. Yeah,
I see, it makes stars, which clears the view. Yeah.

(10:14):
And you know, it's no coincidence that the kind of
light that we can see, that our eyes can pick
up is also the kind of light that can pass
through space. Because that light comes from the Sun, it
has to pass through space to get to us, right,
and and then it has to survive the atmosphere. And
so the kind of light that we can that is
around on Earth is the kind of light that we've
evolved to see um. So obviously it can get here

(10:37):
from the Sun, and so it has to be able
to pass through space for us to see it. Right.
But what's kind of cool to is that just because
there is a gas or a nebula in front of us,
it doesn't mean that we can't see through it, because
if we other kinds of light do go through that
kind of stuff. That's right. When we say visible light,
we mean light of certain frequencies. You know, red, green, blue,

(10:58):
all those other colors that we can see. But light
has lots of other frequencies, right, You can wiggle more
quickly into the ultra violet, you can wiggle more slowly
down into the infrared, or really slowly down to the
radio waves. So we don't usually call those light, you know,
they call them radio waves or gamma rays or whatever,
depending on the frequency, but they really are just still
electromagnetic radiation. There are another form of light, and depending

(11:21):
on the wavelength, they have different properties. Some of them
can pass right through gas and dust. So for example,
radio waves, which are really long frequencies compared to visible light,
it can pass through gas and dust and we can
use that to see into the center of the galaxy. Yeah,
that's pretty cool. It's like having X ray vision exactly,
and we can actually use X rays also. X rays

(11:43):
do also pass through gas and dust. Now, some of
these things, like X rays, they won't penetrate our atmosphere,
So if you want to see that, you have to
have something really high in the atmosphere, like on a balloon,
or maybe even into space, like an X ray telescope
in space to see that. That's interesting, Huh. You have
to go up. You have to fly up like Superman
to have X ray vision, and these days we even

(12:04):
have other ways to see the universe that are not
just light, Like we can see the universe through neutrinos.
There's some weird stuff out there that just makes neutrinos,
and neutrinos passed through almost everything, so they're a really
good way to see really really far away. And then
recently we developed this ability to see gravitational waves. And
this is not even stuff, right. Gravitational waves are the

(12:25):
ripples in space itself, so they can pass through basically
everything matter. Yeah, all right, so that's the answer. The
answer is um. The question was how can we see
so far through space without being blocked by tabula and
other stuff? And the answer is that there isn't that
much stuff out there. Space is pretty empty and even
the stuff that's out there doesn't really block our view. Yeah,

(12:46):
and we have other ways to see through the stuff
that does block our view. And if we were blocked
by nebula and other stuff, eventually all of that stuff
would have turned into stars or moved around. Yeah. Just
wait a few billion years, you know, and the Vuele chain. Yeah, yeah,
just hang out, just hang up. You don't need to
graduate anytime soon, do you have a PhD VSIs. Just

(13:07):
wait if you bill, No big deal? All right, thank
you a Lisandre from Italy. That was a great question.
And before we go on, let's take a quick break.

(13:29):
All right. We're answering listener questions today and the next
question we have here is from Shelley from Australia, from
down Under and Shelly. Shelly asks a really awesome question
and a lot of people wanted the answer to. He's
questioning whether whether you have a real job or not, Daniel,
and I'm brave enough to play this question on the podcast.
Here we go, Hi, Daniel and Johey. I'm Shelly from Brisbane, Australia.

(13:53):
And what I would like to know is how does
physics actually work? How do you come up with the
theory and then create an experiment to test that theory?
What does the physicist to actually do every day? You
get up, you get your coffee, you gotta work, and
then what how do you go from a theory to
an experiment then to an explanation? And I love that question.

(14:16):
I love when she says and then what my question
is is she your wife, Daniel, or is she's sending
a question she wondering what you do all day? No,
but it's hilarious because that's what I do. I get up,
I drink coffee, and then I go to work and
then I go, Okay, now what do today? So that's

(14:36):
that's pretty much the answer. The question is the answer. No,
that's the two sides of academic freedom. You know, as
a professor, you basically get to do whatever you like.
On the other hand, nobody tells you what to do,
so you have to come up with stuff to do yourself. Right,
So every day you answer that question today what. Yeah,
it's a great question. It sort of goes to the

(14:57):
heart of you know, how is science done. I think
she's maybe wondering, like what's your day to day? Like like, um,
she probably knows that there is this general process, but
at any point, how do you decide what to do? Yeah,
so you know, day to day, of course, you get up,
you get your coffee. Then you started answering the three
emails that came in while CERN was awake in Geneva

(15:17):
nine time zones ahead and I was sleeping. And then
when you get through all that, you get to start
to think about it sort of the higher level science, right,
And she asked a question, you know, how do you
go from theory to experiment, Like how do you come
up with an experiment? And I think that's a really
interesting question because a lot of times that is the
way it works. Like a theorist comes up with an
idea saying like I think maybe there's this new particle,

(15:40):
or I think maybe there are black holes out there,
and then it's the job of the experimentalist to figure
out the answer, right, is that correct or not? Do
these things really exist or not? But there's sort of
a step before that, right where you I mean, um,
I mean you have to know what's going on in
the field. You can't just possit these things out of
the blue. You have to know. You have to read

(16:01):
what everyone else has done and what everyone else is doing,
and you kind of have to try to ask a
question nobody else's answered. Yeah, that's certainly true. Although um,
I got a lot of crackpot ideas from homegrown theorists
that haven't yet done that, you know, But um, yeah,
you want to come up with an idea, You want
to come up with an idea that's new. Like maybe
the difference between a professional physicist, um is that you

(16:25):
you spend your life on it, right, you you go
to conferences, you talk to people, you know what's going on. Yeah,
you definitely have to know how things are done and
you know what questions have an answered. In that perspective,
you can sort of think of science like a conversation.
You know, we're trying to figure out what is the universe?
How does it work? And you want to say something relevant,
and so you have to think of like, what is
the question at hand? What is it we're trying to
figure out right now? And how can I test it?

(16:48):
And um, that's the bit about being an experimentalist. I'm
an experimentalist. And you know what is the job actually involve, Well,
it involves coming up with a way to ask a
question of nature or that will reveal the answer. You know,
some theory says I think there's a new particle the
squiggly on. Well, then you can't just ask nature the
question does squiggly on exist or not? It's not like

(17:10):
nature some oracle right that just answers whatever question you want.
You have to trap it, you have to trick it,
you have to corner it. You have to come up
with an experiment. You can do something a physical thing
you can build that will tell you whether this thing exists,
because you know, if you do your experiment and the
data is this, then you know the answer is yes,
this is quiggly on. If you do the experiment and

(17:30):
the data comes out differently than you know, the answer
is not a squiggly on. But that's not trivial, right.
That requires some cleverness. You have to think about the
right way to sort of corner nature and make make
it tell you whether this thing exists by revealing the
answer in your experiment. And part of that is has
to do with the null hypothesis, Right, Like this idea
that where you, um, you sort of assume that this

(17:52):
quiggly on doesn't exist, and you run some experiments and
if you see something that clearly shows you that the
reuigly not existing is not quite likely, then that means
you how something Yeah, exactly, we need conclusive evidence. We
need to see data that couldn't have been produced if
the squigglyon didn't exist, Right, they could only be produced
if the squigglyon existed. We need something that's in that

(18:14):
sense unique, right, it has to be necessary and sufficient
um And so often what we do is in my
particular case, because I'm a particle physicist, is you know,
we're colliding protons together, and if we want to ask
the question does the squigglyon exist? And we think, well,
what would the squiggly on look like in our data?
How would it appear? You know, would it leaves splashes

(18:35):
of energy over here? Would it leave traces of its
motion over there? And then we sort of look for
those telltale signs. But then we have to think about
what else could look like that. Is there anything else
that could mimic it, anything else that could look like
this squiggly on but not actually be the squiggly on.
So a lot of the experimental work that I actually
do involves that kind of statistics, like figure out a

(18:55):
way to look for this thing in a way that
nothing else could mimic. And then but it also works
the other way around, like somebody maybe did an experiment
to look at something else and they found something weird
and said that doesn't fit the theory, and so then
theories have to come up with an explanation for the data. Yeah,
and in my view, this doesn't happen enough. And I
think a lot of people, especially in particle physics think

(19:16):
that it always starts theorist has an idea for a
new particle. Experimentalists just go check to see if that's true. Right,
And there's actually a really lively debate right now about
how do we do this in particle physics because the
theorists predicted, oh, supersymmetric particles will appear at the Large
Hadron Collider, and then we didn't find them. And I
thought some people think, oh, that's a failure. But I

(19:37):
think that experimentalists can be explorers. That we don't have
to just answer the question does this new particle exist?
We can go out and look for weird stuff. Right,
Let's just see what's out there, you know, the way
like when you landed on Mars. You don't ask the
question are there purple cats and dogs there? You just
walk around and look to see if there's some new
kind of life that will blow your mind. So, yeah,

(19:59):
you're absolutely right. Sometimes an experimentalist find something weird, something
that can't be explained with our current understanding, and it
forces us to come up with a new theory when
they can explain that. Yeah, and those those are the
greatest moments in science, if you ask me, Okay, cool,
it's okay, that's m hmm, okay cool. So that's what
you do. And then it's like eleven am. And then

(20:20):
then what do you do? Then it's time for my nap, right,
and then I do this awesome podcast with this cartoonist. Yeah,
I have no moral stand to criticize a lazy lifestyle
or work life. Um, but I think that's the kind
of the general answer is that you know, it's it's

(20:41):
like a it's a conversation, right, Like you're it's not
just you in a room trying to come up with
ideas and theories and experiments. It's like you're conferring with
other people. You're reading other people's work. You're you're trying to,
you know, come up get clues from other people's results
and things like that. Right, it's sort of a conversation
and and and it's a process. Yeah, And it has

(21:04):
to be a conversation because science is just people. Right.
If you do some science and nobody reads it, then
you haven't really pushed human understanding forward at all. Right,
So you have to do something people are interested in
so that they will listen and it will change sort
of the common understanding you'll move forward the wavefront of
human thought. Yeah, yeah, alright, Shelley from Australia. That's your answer, Um,

(21:27):
basically coffee, coffee, coffee, Yeah, exactly, all right. Our next
listener question comes from Alex from Connecticut. Here we go. Hey, guys,
this is Alex from Connecticut and I'm wondering if there's

(21:48):
anywhere in the universe where dark matter is not present? Thanks,
give up the good work. Alex sounds pretty excited about
his question. He has a great traitor voice. He should
do movie traders in a world where dark matter is
not present everywhere. Um. This is a great question because
we've talked about how dark matter, um is. There's much

(22:11):
more dark matter in the universe than normal matter. So
it's a very natural question to wonder, like, is it
feeling the universe is invisible? But is it everywhere? Yeah?
I mean there's not a little bit of dark matter
out there. There's five times more dark matter than like
all the stars and gas and clouds and planets out there, right, Yeah, exactly.
It's a huge amount, and so it's very natural to

(22:32):
ask where is it? And the answer to this question
is yes, there are lots of places in the universe
without dark matter, because it turns out that dark matter
and normal matter basically followed the same distributions. That is,
you can tell where the dark matter is just by
looking for the non dark matter. So who's following who,
who's the stalker, and who's the celebrity. It's um. You know,

(22:56):
it's something of a dance right there. We know about
dark matter only because if gravitational effect on stuff, right,
and so gravity um affects dark matter and normal matter,
and the two pull on each other, and so it's
something of a dance as they tug on each other,
and that's why they're linked together. That's why dark matter
and normal matter are in the same places, because they're
gravitationally attracted to each other. Now, because there's more dark

(23:18):
matter the normal matter, you could probably say the normal
matter is following the dark matter. So in fact, that's
the only way that dark matter can interact with our
matter right now we know of is gravity so far
that we know it's the only way you can interact
with our matter. It might have some interactions with itself
that we don't know about, but to interact with our
matter to see it to affect our you know, the
things that we can test and observe. Gravity is the

(23:40):
only way for us to probe that. And you know,
people really interestingly, people do simulations of the universe without
dark matter. They're like, what would have happened if there
wasn't dark matter? And things just don't coalesce as quickly.
You run the universe, but you run it without dark matter,
and yeah, get totally different results. Yeah, this is amazing, Right,
you can simulate whole universe. It's pretty incredible. And they ask,

(24:02):
you know, what would the universe look like under vary scenarios?
And that's really important because it helps them understand what
was the various fraction of things in the very beginning
and how sensitive um are we to that? Like? And
it was any configuration mostly going to give you galaxies
and stars and planets or is it really sensitive? And
it turns out that if you didn't have dark matter,
then it takes a lot longer for stuff to clump. Right.

(24:24):
The only reason we have stars and galaxies and planets
is because gravity has gathered this stuff together. It turns
out it's gotten a huge boost from all the dark
matter helping to pull it together, and without that dark
matter would take billions more years to get all this structure,
so we wouldn't even be around without the dark matter.
So pretty much dark matter follows normal matter and helps out. Yes,
But pretty much when you look out into the universe

(24:46):
and you let's see what for all the shiny stuff is,
like stars and planets and light, that's kind of pretty
much where dark matter is. Also roughly that's correct. But
if you look at the for example, of galaxy, there's
a huge block of dark matter are also at the
center of the galaxy. But then there's a we call
it a halo. It extends beyond where the visible galaxy is,
but mostly it's a blob centered at the visible galaxy,

(25:08):
right right. I think the question is like, you wouldn't see,
for example, like between here and a dromeda. You wouldn't
see a giant blob of dark matter just floating by itself,
would you? You might probably not, though, yeah, probably not.
But it's possible for dark matter normal matter to get separated,
like in the bullet cluster um. You know, some of
the dark matter and the normal matter got separated because

(25:30):
of big collision, and the normal matter interacts with itself
and the dark matter passes through as far as we know,
so there could be blobs of dark matter, but it's
not like it's evenly distributed, right, So there's lots of
places where we think there probably isn't any dark matter alright.
So the answer to Alex's question is yes, there are
probably many places in the universe without dark matter. Dark

(25:53):
matter clumps together in specific locations. That's exactly right. This
is one case we can give a very crisp answer. Yet.
That's the t L d R. Yes, Alex, Yes, cool.
Before we keep going, let's take a short break, all right,

(26:22):
and so our last question today comes to us all
the way from Iran. So far As from Iran has
a pretty interesting question about the shape of galaxies. Yeah,
here he is. Hi guys, my name is Fasm I'm
from Iran. After listening to your episodes about the galactic
collision and the gravity, I have a question to ask

(26:44):
why all the galaxies and solar systems in the universe
are disc shaped. I mean, if the gravity extends through
all the dimensions the same, why they are planar? Yeah,
this is a great question too. Write You look out
at the sky, you look at these galaxies, and you
look at the Solar system and they all seem to
be organized in these disks. Yeah, they look like flat

(27:08):
um blobs, right, not not like perfectly spherical blobs, but
like flat blobs, right, Yeah, exactly. They're they're mostly flat
um and they're not spherical. Yeah exactly. And so it's
a nevery natural question. It's a totally typical thing to
see out there in the universe. Like if you look
at all the models of of our solar system, they
look like hula hoops, right, one inside of the other.

(27:29):
Why why doesn't it look like um, you know, like
the model, the old model of the atom, where the
hula hoops are in all kinds of directions. Why are
where are the orbits of all the planets sort of
pretty much in the same plane or at the same level. Yeah, exactly.
It's a great question because you could imagine otherwise maybe
the plans would all be zigging zagging around in lots

(27:50):
of different directions, right, even if they each have their
own circle, they could be um, they could be all
sorts of different directions. Yeah. The short answer your question
is angular momentum, right that this is this is conserved quantity.
Is that something you just can't get rid of? If
an object, if a cluster objects, has angular momentum, it

(28:10):
just can't get rid of it. Um. Let's dig into
that just for a moment. Let's just think about momentum
at first. If you have like a rock in space
and you push it, then that rock is gonna go
on forever unless something stops it, right, if it runs
into something or whatever. Otherwise it will go on forever.
And that's because it has momentum. And in our universe,
momentum is conserved. Why is it conserved, We don't know,

(28:31):
but we know that it is, and so things keep
going if you push them. There's another kind of momentum
which is about spinning. It's called angular momentum. You start
something spinning, it will keep spinning right right, unless something
stops it. Right. And you're saying this applies to like
the Earth going around the Sun. That's spinning around the Sun,
and it's hard to not spin right like it's it's

(28:54):
hard to suddenly stop and go straight into the Sun. Yeah.
The only way for that happens for something from the
outside I had to come and like bang into the Earth,
and that could change. That could stop the Earth from
going around the Sun or stop the Earth from spinning.
If you want to stop your angle momentum, you need
to have something from the outside. But a closed system
like the Earth and the Sun or the galaxy or
whatever can't just stop spinning. That anglo momentum can't just disappear.

(29:17):
It has to has to be transferred somewhere or balanced
out by the opposite momentum somewhere else. Right, Like two
objects flying through space can stop if they're being into
each other. Right in the same way, two things spinning
opposite directions could both stop spinning if they touch in
their angular momentum cancels out right, and um, things kind
of have angular momentum because they didn't start from from breast,

(29:41):
you know. Like if you put two stones out in space,
they're just gonna and there's nothing else around them. The
two stones are just gonna fly straight into each other.
But if you they're going at different speeds and they're
going to start circling each other as they get closer
to the other, right exactly exactly, And so you can
imagine sort of the history of our soldiers is to
moral galaxy, depending what you're thinking about, and started as

(30:03):
a big cloud, right, a big chaotic cloud, everything shooting
in random directions, and it might feel like, well, everything
just sort of cancels itself out. But there's one place
where you can draw a line through it, and turns
out that everything is orbiting around that. Right. That's called
the center of rotation. And it's sort of like if
you're holding up a stick, right, there's one place that
balances the stick um where it will be pulled on

(30:25):
by gravity the same amount on both sides. The same
way you find this big cloud. There's some line you
can draw through it around which everything is rotating. Yeah,
and that's that's that point is where basically the center
of the galaxy or the center of the Solar system
is going to form right, yes, exactly, and so everything
is rotating around that, and then gravity does its thing.

(30:46):
It pulls things together as much as it can and
so um, but it can't shrink everything down too much
because it's spinning, right, and the spinning keeps it sort
of fluffed out, but only in the direction perpendicular to
that line, to that rotation sational axis. So along that
rotational access, gravity can switch things down as much as
it wants, right, there's nothing preventing it, but around that axis,

(31:08):
things have to keep spinning, and that spinning keeps them
from getting too close to the center. The same way,
like the reason that the Moon doesn't fall to the
Earth is because it has velocity, right, it's spinning around us,
and so angular momentum can't go away and has to
go somewhere, and it keeps the stuff from falling too
far into that central axis. So that's why everything becomes

(31:30):
a disk. Yeah, and that's kind of why all the
hula hoops sort of emerge, right, Like, like let's say, um,
the Earth is on a hula hoop orbit around the Sun, right,
so we're on a disc and in a circle there
on an oval and and like let's say that there
was another planet there was also going around the Sun,
but it was going in a totally different hula hoop,

(31:50):
like totally maybe perpendicular to ours. And I think the
idea is that, you know, the attraction between our planet
and that other planet, it's not going to make us
go closer to the Sun or or like destroy our orbit,
but it is going to make the hula hoops sort
of merge together, right, I think over a long period
of time, yet they would both come to orbit in
a in another plane that's sort of like the average

(32:11):
between the two, because the rotational center would be some
access that's perpendicular to that new plane. Yeah, this is
the kind of thing. It's it's easier to describe in
front of a chalkboard. We'll use the chalkboard of the mind.
That's that's kind of the idea, is that everyone at
the beginning, everyone's rotating and going in their own orbits,
but over time all these orbits sort of aligned with

(32:35):
each other. And so that's why galaxies and solar systems
they all look like flat discs. Yeah, exactly. The direction
perpendicular to that disc, things can pull together, and collisions
and attraction all that stuff helps balance it all out
and pull it together. But along that disc it can't
it can't get too close in because of anglo momentum.
He has to keep spinning, and that spinning keeps it

(32:57):
from falling in towards the center. Yeah, so like gravity
just squishes is in one direction, but it can't squish
in the other directions because that's where the spinning is happening. Yeah,
and his question was really interesting because he asked about
the dimensions, and you're right that gravity works in all
these dimensions, right, but because we have Anglo momentum and
anglermentum is to find along a plane two dimensions, it

(33:18):
makes it sort of asymmetric, right, that it doesn't get
treated the same way. One really fun exercise is to
think about, like, what would physics be like in four
dimensions or in five dimensions. That kind of can kind
of blow your mind. But if we had like a
four dimensional space, then you would actually have two different
axes of angular momentum that would be conserved, and so
things would look even crazier. Wow, what would you call that?

(33:41):
A blob? And this is why I'm not on the
physics naming committee. Alright, cool. So, the the idea is
that gravity does work in all directions, um, but it
has trouble bringing things together in the direction where they're spinning.
Yeah exactly. And so but it it can bring things
together in the direction they're not spinning, and so that's
why maybe things start out in as a big blob,

(34:03):
but then they eventually get squished down and they picked
kind of the average spin um direction. Yeah exactly. So
gravity is the great flattener of the universe, the great flatter,
the great squisher yeah, she just named squishy t. Yeah,
there you go. You got Newton, You've got Einstein, and

(34:25):
then you've got chamcham contribution to theory of gravity. Oh,
a better name. That's definitely definitely up there. And then
when I break into quantum physics will be the squishy Ton.
I'm gonna go devise an experiment to look for the
squishy ton. That's right, I'm gonna call it to squishy Ton,
and then go get some coffee and then I'm done. Boom,

(34:45):
there's my day and then what then? What? Alright? So
those were awesome questions. I love your questions. You might
think I'm gonna send him a question he's never going
to answer. I will surprise you. Send us a question,
you'll get an answer. You might even hear your voice

(35:07):
on this podcast eventually. Yeah. And if you're Daniel's wife
and have also a question about his lifestyle or habits,
just interrupt me anytime, anytime. He'll probably answer that question
without interrupting you. So um to night even work out
podcast with an audience of one. But thanks for joining

(35:27):
us once again and again. If you have questions, please
send it to us at Questions at Daniel and Jorge
and dot com. Thanks for listening and thanks for asking questions.
See you next time. If you still have a question
after listening to all these explanations, please drop us a line.

(35:49):
We'd love to hear from you. You can find us
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