September 14, 2021 • 46 mins
Daniel and Jorge dip the french fries of knowledge into the mysterious condiments of the Universe and answer questions from listeners like you!
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Speaker 1 (00:08):
Hey, Daniel, I've been thinking about black hole. Watch out.
That's a real rabbit hole. Yeah, I'm definitely stucked in.
But here's my question. Can you make a black hole
out of anything? Like? Even rabbits? Theoretically you can, but
that's a lot of rabbits. But you don't actually need
a lot of rabbits, right, Like you can just take
a few rabbits and squeeze them together a lot, right,
(00:29):
as long as they started a release of liability, I
suppose anything is possible. Well, I got their pop prints.
I think that counts right, But I guess my bigger
question is does that mean you can make a black
hole out of anything? Yeah? I think so, even dark matter? Yeah,
anything with energy? About a black hole out of photons? Absolutely?
And you know the truth is, I'd rather you sacrificed
(00:50):
photons than rabbits. What if they're light rabbits. I am
or hammy cartoonists and the creator of PhD comics. Hi,
(01:12):
I'm Daniel. I'm a particle physicist and a professor at
UC Irvine, and I'm at least forty seven rabbits. You
wave forty seven rabbits or you own forty seven rabbits,
or you are forty seven rabbits in the costume of
a human. I think philosophically, I'm somewhat equivalent to forty
seven rabbits and intelligence, civil arm or ability to eat carrots. Yeah,
(01:34):
you know, you link two rabbit brains together, you get
something which is much smarter than just two rabbits. So
now you have forty seven rabbits. It's like rabbits to
the power. Oh my goodness, that is one massive bunny brain.
But anyways, welcome to our podcast, Daniel and Jorge Explain
the Universe, a production of I Heart Radio in which
we apply our human brains and our bunny brains and
(01:54):
our hamster brains to the deepest and biggest questions of
the universe. We don't hold. We tackle questions like how
did the universe get here? And where is it going?
What's it made out of? And how does it all work?
Because we think the universe is comprehensible. We don't know why,
but human brains have somehow managed to chisel into the
mysteries of the universe and gain little shards of understanding.
(02:17):
And our goal on this podcast is to take those
and explain all of them. To you, as well as
the deepest, biggest open questions that remain for humans and
bundies to unravel. Yeah, because it is a pretty mysterious
universe full of questions and things that we have yet
to discover, from what is most of the universe made
out of to what is the fundamental units of space
(02:40):
and time and matter in this cosmos? Or is there
even a fundamental unit of space and time in this cosmos?
Or is it just rabbits all the way down? One
of my favorite things about asking questions of the universe
is that anybody can do it. You look around you
in this weird, wild, crazy, violent, do full universe, and
(03:01):
so many things are puzzles. So many things beg you
to ask questions about them. Yeah, daniel A re allowed
also hair brained questions was in Rabbits. Sorry, I just
had to get that in because I realized after we
had our earlier exchange that that was such a little
hanging fruit for a pun and a joke. I know,
I can't believe you didn't hop up to that joke earlier.
I'll keep my ears out for funnier jokes, But yeah,
(03:23):
it is an interesting universe full of questions. And full
of inquisitive minds with questions about the universe, because I
think we all look out there into the cosmos, into
the night sky, and we look at ourselves, and we
we gotta wonder, like, what's going on? How does it
all work? What's it all made out of? That's right,
and we are not the only ones actually thinking about
the overlap between cosmic questions and small furry creatures. Last
(03:47):
night I got a fun question over email from a listener,
Evan Cleave, who wanted to know something deep and important
about the universe. But really, what was the question? Well,
I have to read it to your word for word,
because otherwise you won't believe it. It says how Low Daniel.
I have a very serious and important question. How many
hamsters floating in space would it take to have enough
(04:08):
mass to come together gravitationally to achieve nuclear fusion and
become a star? The world needs to know. Well, that's
the kind of world I want to live in, where
everybody needs to know how many hamsters you need to
make a hamster sun? Is that what you would call it?
A hamster star? A hamstar, a hamstar exactly? Yes, But
(04:29):
I swear that we had written this cold open about
rabbits and black holes before we got this important question
from Evan about hamsters and stars. It just goes to
show you how there's some sort of connection between rodents
and massive space objects. Science needs to probe this a
little more deeply. I think, Yeah, who knows how many
flying hamsters are there are out there in space? Right? Like,
(04:51):
we literally don't know. There could be a lot that's
true beyond the observable universe. It could be just all
hamsters to the edge of the universe. Most of the
universe could be hamsters. You're saying, yeah, we could be
living in a hamstar. We don't know. I think we're
all hamstars. Really, it's a pretty hammy podcast for sure.
Do you have an answer? Did you calculate how many
(05:12):
hamsters you need to achieve fusion or is that even possible?
Can you make a star out of hamsters? Oh? I
have an answer, and you know, given the urgency and
clear importance of this question, I cleared my afternoon and
shared an emergency task force just to address this question.
I pulled in international experts of planetary scientists, fusion professors,
hamster owners, you know, and we've met for an entire afternoon,
(05:34):
did some calculations, and you know, essentially to make a
star that achieves fusion, all you really need is enough stuff.
You get enough mass together and gravity will pull it
together and create the conditions you need for fusion. And
the minimum threshold there is about eighty times the mass
of Jupiter, which is about one point six times ten
(05:56):
to the twenty nine kims. So it's a big mass. Wow.
I'm glad that was a productive afternoon and you didn't
just sit there spinning your wheels in a hamster wheel. No,
I didn't just weasel out of this question. I really
took it seriously. But you're saying that if I had
an eighty jupiter's worth of hamsters, it would become a son.
It would become a son. Now, technically that calculation is
(06:17):
done assuming that you have eighty jupiter's worth of hydrogen,
and you know, hamsters are made of heavier elements. That's
carbon in there other stuff. But mostly the same calculations
will work. Really, you can, like, if you had, you know,
eighty jupiter's worth of carbon, it would turn into a star.
That's not necessarily the same, is it. It's not exactly
the same but approximately as long as it's lighter than iron,
(06:39):
then gravity can do its thing and compress it. It
won't burn for nearly as long as a massive hydrogen will,
but carbon and oxygen will still fuse, and you'll get
further up at the periodic table. I see you need
gassy hamsters, not iron hamsters. You can't have tony star hamsters.
That wouldn't work. Hamster iron man would be a different.
(07:00):
So you need about eighty Jupiter's worth of hamsters to
ignity hamster. That's right. And since hamsters are about thirty
grams each, averaging over the various kinds of hamsters, that
means it requires about five times ten to the thirty hamsters.
That's five point three million YadA hamsters. M that's a lot.
(07:21):
You know, you'd be counting them and then you'd be like, YadA, YadA, YadA.
It's a YadA hamsters for sure. All right. Well, um,
I guess that's good that there aren't hamidy hamsters on Earth,
because then we'd be toast or the hamsters would literally
be on five. Well, those are the kinds of questions
you get on the internet, and Daniel, you get those
a lot, right, and you always answer them. That's right.
We answer every question you send us, the serious ones,
(07:42):
the deep ones, the silly ones. We write all our
listeners back because we think that science is just part
of being human and we want everyone to get to participate.
So if you have a question about the nature of
the universe or how many rabbits it takes to form
a black hole, please write to us to questions at
Daniel and Jorge dot com. Yeah, and Daniel always ask
(08:04):
for this emails. But sometimes we answer those questions here
on the podcast live in front of thousands and thousands
of people. Yeah. Sometimes people ask the question and I think, oh,
I bet a lot of folks would have that question,
let's dig into it on the podcast, or it just
sounds like a lot of fun, and so we select
some subset of those questions to be explored right here
on the podcast. Yeah, so today we're gonna go full
(08:26):
hamster on three pretty interesting questions we got over the
internet about electrons and when they radiate light, about the
curvature of space and equals mc squared, and also about
the Higgs field and how long has it been around.
That's right, and these are just questions from people being
curious people trying to fit together their pieces of understanding
(08:46):
into a larger mosaic so they can have in their
minds the entire universe. And when two pieces don't quite
fit together or don't give you that satisfying click, that's
when you're doing physics, when you're applying your knowledge and
trying to understand the whole universe at once. So if
you get stuck in that situation, please write to us
so to be on the podcast. We'll be answering listener
(09:12):
questions number seventeen. So we've done seventeen of these listener
questions podcast, Daniel, that's about something like fifty something listener
questions we've answered live. Yeah, that's right exactly. And I'm
really glad that the listeners get to hear their questions
get answered, and they get to participate in the science
process because this right here, this is science happening. I
(09:33):
feel like you just demoted science, Like if this counts
as science, it's a big tent, man, it's a big,
big tent. We're way in the outskirts of the tent,
like halfway in getting wet on one side of our body.
I'm not about science gates keeping man science is for everyone.
All right, Well, let's crash the gates and let's go
full science here and well, the first question will tackle
here is from Tim who has a question about electron radiation. Hello,
(09:57):
Daniel and Johe love podcas casts. You're doing great work.
While discussing a listener question, you mentioned that electrons moving
up and down antenna generate photons. That sent me down
a Google rabbit hole where I found that syncotron's use
electrons going around in a circle to generate X rays.
Similar concept, but it got me thinking why do electrons
(10:21):
bound to atoms going around in a circle not produce
photons as well? Can't wait to hear the answer and
look forward to hearing from you. Keep up the good work.
All right, thank you for that awesome question. I'm not
quite sure I understand the question though, Daniel. The question
is about when electrons give off light, and we did
a fun episode with listener questions where we talk about
(10:43):
essentially how electrons make photons. Like, somebody asked how you
get an electron to shoot off a photon? What makes
that happen? And when answering that question, we explained that
the way you get an electron to radiate is essentially
you accelerated, you wiggle it like the pick. Sure I
have in my mind is that the electron is surrounded
by an electric field. An electronic tracts positrons and it
(11:07):
repels other electrons, and it does so using its electric field.
So it's electric field sort of fills space around it.
What happens when you wiggle that electron is that the
electric field also wiggles. Is like a ripple in that
electric field isn't change instantaneously, and so that's what we
call a photon. So the answer we gave there was
that to generate a photon, to get an electron to
(11:29):
radiate a photon, to shoot off a little piece of light,
all you have to do is accelerated. But his question is,
what about electrons and atoms? Aren't they moving in a circle,
which is acceleration, So why aren't those electrons just shooting
off photons all the time? Right, Okay, I think I
got it. So you're saying electrons generally, if you wiggle them,
(11:50):
if you accelerate them, they give off light. And then
is that just electrons or anything that you know electromagnetic,
anything that has electric charge will give off a photon
if you accelerated, so amuan or any other particle that
has electric charge, if it accelerates, it will give off
a photon because it's acceleration changes the electromagnetic field and
(12:11):
the information moving through that field. That's what a photon is, man, right,
And then it loses some energy or is it always
just giving off photons in every direction forever? No, it
loses some energy exactly. That's how an electron essentially breaks. Right.
An electron changes direction by like pushing off a photon
in the other direction. Like, how can an electron turn, Well,
(12:31):
the only way for it to like change its trajectory
is the same way you would in space, which is
throwing something out the back. An electron turns in space
changes direction, which is essentially acceleration by tossing a photon away. So,
for example, if you want electrons to move in a
circle the way we have and some accelerators like singletrons,
for that to happen, electrons have to constantly be radiating
(12:54):
off photons to push them in the circle. And you're saying,
that's kind of how antenna work, because there's electrons wiggling
inside of an antenna, and that gives off the photons
and the electrical signal. Yeah, in both directions. You can
generate photons using electrons by taking them and using current
from your signal to wiggle the electrons, and that generates photons.
(13:17):
And that's exactly what an antenna is. That's how, for example,
those tall towers from radio stations generate radio waves as
they have like electrons moving up and down those antennas,
and the frequency of the electrons motion is the frequency
of the photon that they generate. It's very simple and
direct connection between the motion of the electron, the motion
of the electric field that it's connected to, and the photon,
(13:39):
which is just wiggling of that electromagnetic field. All right,
So I guess the question is that if a wiggling
electron gives off a photon, then wouldn't electrons wiggling around
an atom also be giving of photons all the time? Yes,
And it's actually a really deep and important question about
how atoms were and something that people struggled with for
(14:02):
decades in the early part of the century because remember
that the first picture of atoms, and the one that
Tim describes, is sort of of electrons moving around the
nucleus like in a little orbit. The sort of Neil's
bore picture of the atom was that it was sort
of like a little planetary system. You have these electrons
whizzing around like little classical objects, like tiny little balls,
(14:24):
moving around in a circle around the nucleus. And if
that were true, if electrons actually were moving in those
little circles around the nucleus, they should be radiating, they
should be losing energy, should they should be giving off photons,
And if they would, then they should just fall right
into the nucleus and they should collapse. So if you
do the calculation, is suggests that like the hydrogen atom
should only last for like ten to the negative twelve seconds.
(14:46):
But of course we see that hydrogen is stable. Electrons
can hang out in these atoms and they don't collapse
and tend to the negative twelve seconds. So this was
a big puzzle in physics, not just for tim but
for like the brightest minds in physics for many years. Right,
because that's the classical view of the atom. Right, It's
like you imagine, or you draw a little dot, and
then you draw some electron dots like whizzing around in
(15:08):
like elliptical orbits around the nucleus of the atom, right,
And so if that picture is true, then you're saying
that that would not be sustainable because you know, the
electrons are moving in a circle, which means we're accelerating
and decelerating, and that means that they should be giving
up light all the time exactly. And this is just
what I was talking about earlier. You like take your
(15:28):
understanding of something and you apply the rules to you said, well,
if this picture is true, then why doesn't this happen
or why doesn't that happen? Right? That's the core of
doing physics, of doing science, of trying to link together
all of your understanding and make sure that it all
like fits together in a way that makes sense, because
you shouldn't have different rules for different situations. And so
that's the fundamental question that Tim is asking is why
(15:50):
doesn't the electron essentially collapse into the nucleus instantaneously? M alright,
So then what's really going on here? Why don't the
electrons moving and on the nucleus of the atom give
up light? The reason is that they are not really
little classical objects. They're not really tiny little balls in
orbits that are moving with circular motion the way that
we imagine them in that picture of the atom. They
(16:13):
are fundamentally very, very different and strange objects. There are
quantum mechanical objects that don't have a path. Like an
electron is not like a tiny little object that really
is moving along some path in space and time. We
just don't know exactly what it is. It doesn't have
a path, that doesn't have a well defined location as
(16:34):
a function of time. It's a quantum object. It's fundamentally
very different, right. I think you're saying that the electron
orbiting around the nucleus of the atom is not really orbiting, right,
like the center of mass or the center of the electron.
It's not really like going in a circle. It's more
like kind of stationary, right, Or it just has sort
of a mathematical equivalent of orbiting. Yeah, it's not even
(16:56):
really mathematically equivalent to orbiting. It's like not really orbiting.
Act all. The way to think about it is not
as a tiny little grain of matter in motion around
the nucleus. It's something really totally different. It's a quantum object.
What you should think about is that the electron is
a tiny little packet of energy you know, just the
same way the photon is a little packet of energy
(17:17):
in the electromagnetic field. The electron is a little packet
of energy in the electron field. So what you should
think about it instead is like a little blob of stuff.
And as you said, it's in a stationary state. It's
like in a stable configuration. It's like if you've trapped
this little thing in a container. It's just hanging out
in there. It's not actually in motion. So the best
(17:38):
way to think about this is a little pack of
energy in its lowest possible state. So then I guess
why do we always use the word orbiting and like,
you know, when we talk about electrons and then the
end we always say, you know, the electron is orbiting?
Is it? Because it's sort of like an analogy, you know,
like an orbit is kind of like a stable energy level. Yeah.
(17:58):
I think we probably shouldn't use the word orbit because
it's very misleading, but I think it's historical. It shows
the sort of the development of our thinking. We've started
from a classical idea and we've been gradually moving more
and more towards these quantum ideas. So now we talk about,
you know, orbit tolls which represent like energy densities. Still
that this sort of suggestive because you're suggesting the electron
(18:19):
has a location, it just has like a probability to
be here in a probability to be there, when really
the location of the electron and its motion is not
well defined until something actually interacts with the electron. And
so often these classical analogies are easier to understand, but
they're often misleading as well. All right, well, then it
sounds like the answers to the question is that electrons
(18:41):
in atoms don't radiate photons because they're not really accelerating, right,
they're not really moving, and so nothing would sort of
prop them to shoot off a photon. That's right, and
sometimes they do shoot off a photon. Remember that there
are electrons in like higher energy states. There's a ladder
of states there, and if you're in a higher energy state,
then you can actually move down onto a lower energy state,
(19:01):
and the way you do that is you shoot off
a photon. So, for example, anytime you see a gas
that's like glowing, you know that's gas that's been energized.
The electrons have extra energy and they give off photons
and go down to a lower energy, but most atoms,
the electrons are at their lowest energy level. And one
really interesting thing about quantum objects like an electron is
(19:21):
that they have a minimum energy level. Like the electron
can't go into the nucleus. They can't like settle down
to a zero energy state, because there's a minimum energy
to every quantum field. This is called the quantum zero
point energy. So the electron can't collapse into the nucleus
because it's already at the lowest possible energy level. I see.
All right, So then electrons and atoms can radiate photons,
(19:44):
but it's not because of the wiggling or the exploration.
It's because they jump from one energy state to another. Yeah,
all right, Well, hopefully that answer is Tim's question, and
so let's get into our two other questions for the episodes,
one about the curvature space and the equals mc square
and the other one about the Higgs field and whether
or not we can live without it. But first let's
take a quick break. All right, we are answering listener
(20:17):
questions today, and our next question comes from Pete, who
has a question about energy and the curvature of space. Hi,
Daniel and Jorge my name is Pete. I have a
question about spacetime curvature. According to the general relativity, we
know space curves in the presence of matter or energy density.
But can we detect the curvature of space or ripples
(20:40):
in spacetime from just energy density alone and not through
the effects of matter like black holes and neutron stars
and stuff. Given that E equals mc squared, you would
think that energy has tremendously more influence throughout the universe
than just matter. But can we detect gravity waves from
things like supernova or quasars? Thanks very much, I love
your podcast. Awesome, Thank you, Pete Daniel. I feel like
(21:02):
I need an episode that explains these questions much less
trying to answer. I feel like I need a listener
questions questions episode about this one. You picked some pretty
tough ones today. Did you do that on purpose? Yeah?
I thought you needed a challenge. No, I just thought
these were fun. Some of these made me go off
and do some research, which is always something I enjoyed doing.
(21:23):
One of my favorite things about this podcast is that
it gives me an excuse to go off and read
about areas of physics I've always been interested in but
never had time to dig into m All right, well,
let me see if I can interpret this question. So
I think Pete is saying that we know that gravity
and mass bend space and curve space, right, and we
also know that energy does that too. So I think
(21:45):
this question is can we detect this bending of space
from just energy, because there should be a lot of
energy in the universe, especially if the equals empty squared,
because that means that the energy is much more powerful
than matter. Yeah, exactly. I think that's the question because
general relativity doesn't just say that mass bend space. Mass
does bend space, but mass is just an example of
(22:06):
the category of stuff that can bend space, which is
anything essentially with energy density. And it's actually, for those
general relativity nerds out there, a little bit more complicated.
There's a stress energy tensor, so it's also dependent on
how that stuff is arranged, but it's close enough to
say that anything with energy can change the shape of space,
and not just matter. Matter is an example of energy.
(22:28):
So I think his question is why don't we see
space being bent by energy because equals mc squared suggests
that energy should be super powerful in the universe, right,
meaning like, if I see a neutron star giving off
a lot of light, do I see space bending because
of all that light coming out of it? And I
think it's useful to sort of dig into the second
part of his question first, like this question, but E
(22:49):
equals mc squared and what that means. It's certainly true
that mass contains a lot of energy. Right, equals mc
squared means that mass is very dense with energy because
the C squared is a big number, right, ce is
the speed of light, which is three million meters per second.
So you take a little bit of mass and you're
multiplied by a big number squared to get how much
(23:12):
energy is stored inside that mass. And we know that,
for example, because you can make like a huge bomb
with a tiny little bit of fuel by getting that
energy out of mass. That's how nuclear weapons work. Right,
So we know that mass is very very dense with energy, right.
And I know from our conversation is that basically you
can also say that mass is just energy, right, or
(23:33):
in a way, mass is just like a measure of energy. Yeah,
So it's all sort of the same thing anyways, Exactly.
That's the point I want to make, is that what
is that mass anyway, It's really just the energy inside
the object. Like most of your mass doesn't come from
the stuff that makes you up, the little corks and
the electrons. It comes from the energy of those objects
being held together. So your mass, how much your bending
(23:56):
space is actually just from your internal energy. Like the
bond between your objects is what gives you mass and
helps you bend space. So even if you're just looking
at a neutron star or a black hole, the reason
it has mass is because it contains a lot of energy.
So basically, every time you're seeing space bend, it's just
because of energy. Right. Well, I think most of my
(24:17):
mass comes from French fries. But there's a different topic altogether.
I don't think there's a term in Einstein's equation for
French fries, but maybe you should have added one. Well,
he was German, so I think he's worn too sausages
or something. What is the French friese density of the
universe anyway, another deep question of physics we can't answer.
I mean, French fries do you need to make a star?
(24:37):
I don't know your star. How many French fries have
you eaten? That's probably more than the number of hamsters
in the universe more than the number of hamsters you've eaten.
I hope somethings that even with him. Then then we
get a black hole. But I think what you're saying
is that mass is energy, and so you know energy
is causing the bending of space out there. But I
think maybe Pete's question is born like can we see
(25:00):
the bending of space just from energy that's not associated
with mass, right, because there is energy that's not related
to mass too, right, Yeah, there is absolutely. Like you
take a photon, A photon is just energy. It has
no mass, right, So lots of radiation can be massless,
like gravitational waves are also a form of radiation. They
(25:20):
have no mass, but there's a lot of energy there.
And so I think his question really is like, can
you just take photons or gravitational waves massless energy and
use that to bend space? Whoa wait, so it's not
a gravitational wave was a bending of space. You're saying
that the bending of space can cause the bending of space. Yeah. Absolutely,
That's the crazy thing about gravity that's sort of nonlinear
(25:42):
that way, right, sort of keys off of itself, and
that's one of the things that makes it so difficult
to develop a quantum theory of gravity, like gravitons would
interact with other gravitons, and you know the way that
like photons don't write, photons don't interact with other photons.
That's one reason why electromagnetism is easier to calculate and
think about, and then other theories like the strong force
(26:04):
where gluons interact with other gluons or gravity where things
get nonlinear for similar reasons. M M all right, Well
then Pete's question I think is can we detect the
bending of space from just photons and or all that
energy flying around the universe or is that somehow in
a different category of space bending. Yeah. I think there's
two different answers here. One is like is it possible?
(26:25):
Could you do this? And the other is like why
don't we see it more happening in the universe today?
And to answer the first one, we think that you
could in principle, if you took enough lasers that were
powerful enough and you focused them on a single point
so you overlapped huge number of photons in a tiny
little space, then you would create a black hole. Mmmmm wait, wait,
(26:49):
if you shoot enough photons into one space, you might
create a black hole. That sounds crazy, right, nobody would
ever try to do that. Would day supervillains out there?
Take note in your layers underneath volcano. We are giving
the prescription today for how to create a black hole.
At the Large Hadron Collider, we shoot protons together a
very high energy. The idea is the same. If you
(27:10):
have enough energy in those collisions, you might have enough
energy density to create a miniature black hole. Same idea
with photons, just different kind of particle. If you build
enough big lasers and overlap their beams in one tight
little spot, you could create a black hole. That people
have done the calculation, and you'd need to have like
a single laser pulse have the same amount of energy
(27:32):
that the Sun produces in a tenth of a second.
So we're not talking about like the kind of lasers
that humans can build currently. We're talking about like enormous
alien terra scale projects lasers to build a black hole.
Oh wow, Well, first of all, I feel like you
just admitted to being a supervillain, Daniel. No, no, no,
I'm a consultant for supervillain. Isn't that what all these
(27:52):
listener questions are really about you're just a betting the
villains right for money. I'm just a scientist answering hypoth
medical questions about how to build a Doom's Day device.
That's all. That's right. You're just asking for a friend
while stroking a cat in their lap, all right. So
it is possible to bend space with just energy, with
just photons, and you can even make a black hole
(28:13):
if you overlap enough photons in one spot. Now, the
other part of Pete's question was why don't we see
more of that in the universe, because like there's a
lot of light in the universe, there's a lot of
you know, radiation being admitted and sing everywhere. Do we
see a general bending of space from that energy? So
the answer is that radiation does contribute to the overall
general bending of space. Like when we measure the curvature
(28:35):
of the whole universe, we measure how much energy density
there is, like per volume, and that affects the whole
bending of space. And part of that budget is radiation
is like includes the photons and the gravitational waves and
all the other kinds of radiation that are in every
unit of space. So the answer is Yes, that happens,
and we can measure it. We can measure the radiation
(28:57):
component of the universe, and we know it does contribute
to the bending of space. But there isn't very much
radiation in the universe. Like if you look at the
pie chart of the energy budget for the universe per
like unit of space, it's mostly not radiation. Most of
the energy in the universe is dark energy. Some other
fraction of the energy and universe is matter. Very very
(29:21):
tiny sliver of the energy of the universe is in
the form of radiation. So it's there. It contributes, we
can measure it, but there's just not very much radiation
in the universe right now. I see. So you're talking
about like a specific type of energy, which is like
light or radiation. You're saying, that's a pretty small percentage
of the matter and energy, right except the non dark
(29:44):
energy stuff in the universe. Yeah, exactly what you have
to include the dark energy. Dark energy also contributes to
the overall curvature of the universe. And you know that's
super interesting, Like we have just about as much energy
per unit volume as you need the universe to keep
the universe to be flat. So the overall curvature is
basically zero. That's something we don't even really understand very well.
(30:05):
All the energy adds up to like exactly the right
number to make the universe have like flat curvature, which
is weird. But photons and gravitational waves and other kinds
of radiation are a tiny little sliver of that. But
the interesting thing is that that didn't used to be
the case. There was a time in the history of
the universe when radiation dominated the energy budget right at
(30:27):
the beginning of the universe, right, that's right, very early on,
the universe was like crazy lousy with photons, Like photons
were everywhere. It was mostly photons. They were bouncing around,
they were being created. The place was hot and dense.
So the first like fifty thousand years of the universe
we think was radiation dominated. Then of course things cooled down,
(30:48):
and when things cooled down, that radiation turns into matter
and then doesn't oscillate back into radiation. So for example,
a photon whizzing around becomes an electron and oppositron, and
maybe those guys go off in opposite directions and don't
recombine to make an electron. And because the universe is
cooled and more dilute. There aren't like other particles for
them to annihilate into, so instead of matter and antimatter
(31:11):
annihilating each other, they just sort of like go their
own ways. And then we have the universe being matter
dominated for like ten billion years, So the universe was
radiation dominated, but only for a very short while in
the early universe, right, I think you're saying that right now,
like where we are now in the history of the universe,
the universe is too cool or not bright enough to
(31:33):
really see the effects of like right energy space bending. Yeah,
that's exactly right. But there is dark energy, but that's
kind of a different kind of energy, Like we don't
love dark energy in with all of the other types
of energy. Yeah, exactly, even though it has the word
energy in the name. Well, it is a kind of energy,
but it's not a kind of radiation or a kind
of matter as far as we know. So if you
(31:54):
have those categories, dark energy is most of the energy,
and the universe is like the rest of it is
matter and radiation, but of the matter and radiation portion,
most of that is matter. So yeah, there is radiation
in the universe, but it's a tiny sliver, and the
history I think is super fascinating. In the first fifty
thousand years it was all radiation, then the next ten
billion years was matter dominated, and the last four billion
(32:17):
years or so have been dark energy dominated. So we've
seen like these different phases of time where different components
are dominating the energy budget of the universe, until we
expand our serviable universe, and then it's hamster dominated universe. Right,
the hamsters belong in the matter of category, the radiation category,
or are they their own kind of energy? All of
(32:38):
the above. It's a hamster powered universe or none of
the above. It's right, We're all just the giant wheel
spinning because of the hamsters. Feels like it sometimes. All right, well,
I think that answers Pete's question. Can we detect the
curvature space from just energy? And the answer is yes,
But right now it's pretty faint, although it used to
be much more significant. So let's get into our last
(32:59):
question of the EPISO. So this one's about the Higgs
field and whether or not we can live without it.
So let's get into that. But first let's take another
quick break. All right, we're answering listener questions, and we're
(33:22):
at our last question of the episode. This one is
from Alex and Ward from Belgium, who are a father
and son question asking team, or maybe they're a hamster
and rabbit, but who knows talking hamster and rabbit. Do
you think they're eating French fries, Daniel or Belgium fries?
What do they call them in Belgium? I think they
call them palm freed. And if they're eating them, they're
(33:43):
probably eating them with mayonnaise, which is awesome. I am
definitely in the mayor with fries camp. What about you?
Oh my god, are you serious? Wow, We're gonna have
to revaluate his entire friendship. Yeah, I love it. And
if that's the end of our friendship, then I'll stand
by that line in this thing. It's delicious. Mayo is
delicious and basically everything I like mixing them together. Actually
(34:05):
a little mayo, a little catch up. I think you're
a magic thought. That's right. I mixed the light and
the dark sides of the force, the matter and the
antimatter of condiment. All right, Well, Alex and White have
a question about the Higgs Field. Hi, Daniel and j
you'r Alexander and what's two huge fans from Belgium. We
(34:26):
love your book and podcasts. Alexander, who is twelve years old,
read in a science magazine that the Higgs field was
created sometime after the Big Bang, and you asked me
the following question about us. If the universe started expanding
at at a big bang, and the Higgs field was
created after the Big Bang, and the information cannot go
(34:46):
faster than speed of light, and the expansion of space
goes faster than light, then shouldn't there be a place
in the universe where there's no Higgs field even today?
A really hard question and I really have no maybe
you can help, thank you. All right, I agree, it's
a pretty tricky question, and I'm glad we're here to
(35:08):
answer father's questions. Should we tackle purity next? And that's right.
We are the backup parents online and the Birds and
the Bees and the Hamsters. I think that's a different
podcast though, we should, you know, stick to our specialty. Yeah,
you should go listen to Creature feature for that one.
All right. Well, the question I think here is I'm
trying to wrap my head around it because it's it's
(35:29):
a little tricky. I think I think he's saying that
if the Higgs field was created after the Big Bang,
shouldn't there be a part of the universe with no
Higgs field, Because I think he's thinking that maybe there
was a big emptiness, or there was larger universe, and
somewhere in the middle there was a big bang which
started the creation of the Higgs field, and so shouldn't
there be parts of the universe without the Higgs field.
Do you think that's what's going on in his head. Yeah,
(35:50):
I think that's the question. And so there's a bunch
of interesting stuff there, like this idea that the Higgs
field is created after the Big Bang and where it
was created and then how it spreads out through the universe.
Has a bunch of fun ideas there to disentangle. All right, Well,
let's recap really quickly. What is the Higgs field in
the first place. Yeah, So the Higgs field is this
thing we discovered about ten years ago. We suspected it
(36:14):
existed for like fifty years, but it only found confirmation
at the Particle collider in twelve. And if a field
that we think fills the whole universe and interacts with
particles in a way, that gives them mass. So the reason,
for example, an electron doesn't have zero mass is that
it flies to the universe and interacts with the Higgs field,
which changes the way it moves so that it looks
(36:34):
like it has some inertial mass. It means that it
takes a force to push the electron to speed it up,
or also forced to slow it down. So the Higgs
field affects how particles move in a way that gives
them mass. Cool, and we knew about it for a
long time, but we discovered that recently. So that's the
Higgs field. But what does it mean that it was
created after the Big Bang? Like it wasn't always there,
(36:57):
or was it there but not active? This is actually
a really anxiest and deep question that goes to like
how we think about our physics. You know, we are
trying to find the deepest rules of the universe. We
think that maybe, as you were saying before, there are
like fundamental rules to the universe, like the equations that
cover everything. Now we don't think we have found those equations.
We have a standard model of particle physics that works
(37:19):
really really well, but we don't think that the equations
we have are like the ones that are really fundamentally true.
We think the equations we have sort of work for
the conditions that we have studied, and we don't think
that they're like the deep and true equations. So what
that means is that the laws we're talking about, including
like the existence of the Higgs field, are really just
like effective laws. It's sort of like if you are
(37:40):
living in ice and you've been studying the way ice works,
the crystal structure of it, and how it moves, and
how energy moves through it. The laws of how the
ice works are not like fundamental to the universe. They're
just descriptions of how the ice works, the physics of
that ice. And so in the same way, we suspect
that the universe used to be hotter, used to be denser,
and so it's effectively different laws of physics were at play.
(38:03):
So when we say the Higgs field was created, what
we really mean is that the universe cooled down to
a point where it makes sense to talk about the
Higgs field. Where the Higgs field is like a useful
mental idea for doing physics. I see, It's just we
don't know if the Higgs field is a fundamental thing.
You're saying, like there may be like higher laws or something,
But at least from what we know and what we
(38:26):
can see around, the Higgs field is a pretty good
description of what's going on. But that's not always the
case exactly. We're pretty sure that it isn't the case. Like,
if you try to take our theories and apply them
to really really crazy scenarios at the very beginning of
the universe, they just don't work. So we're pretty sure
that our laws, including the Higgs field, are not the
true laws of the universe. They're just the ones that
(38:47):
we have found that describe the situations we've been able
to explore. So if somebody says the Higgs field was created,
I think that's a little bit misleading. What they really
mean is that the universe cool to a point where
the Higgs field makes sense as a way to think
about the universe. M But I guess the weird thing
about it is that the Higgs field feels really fundamental, right.
It gives things mass. So does that mean that at
(39:09):
some point we didn't have mass? It like mass didn't
make sense in the universe. It could be It could
also be that there are just different rules, different ways
to get mass, or it could be like mass is
not an important concept. You know, everything that we're talking
about in the universe, we don't know if they are fundamental,
like essential elements of the universe or just emergence stuff
that like comes out of the complexity of the universe.
(39:32):
And you know, that's easy to think about for some things,
like for example, we have ice cream in the universe.
Ice Cream feels important, especially in a hot summer, but
it's not fundamental. You can imagine there could be universes
without ice cream, right, no big deal. Well, I beg
to different Daniel, what's the universe without ice cream? It
might not be worth living in. But you know there
are other things to difference rise into. But you can
(39:53):
also think that same logic and applies to other things
in the universe, like the Higgs field or even like
space it's self. Right, we talked in the podcast about
whether space itself is actually fundamental to the universe or
if you could have a universe without space. And we
physicists feel like, well, we don't really know the true
nature of the universe. We've just been studying this one
particular slice of the universe in a certain energy range,
(40:16):
a certain temperature range, because that's the one we live in,
and we know that our theories we try to do
calculations don't work at higher temperatures, and so we suspect
that some of the stuff that seems fundamental is actually
just emergent. It's just like an interesting property that comes about,
but isn't like deeply true about the universe. I guess,
going back to Alex's question, you're saying that the universe
(40:39):
at some point cooled down enough to where the Higgs
field came into effect, basically, and so I think his
question is like, did that happen everywhere at once or
did the universe sort of cool differently in different places,
and so what does that mean? Or is it cooling
right now in different places differently. So it's that there
are spots with the Higgs field and spots without the
Higgs field. Yeah, that is a really cool question. I
(41:01):
think the origin of his confusion is that he imagines
that the Higgs field was created in one place and
then would have to spread out through the universe. And
he's right that because information travels at the speed of light,
and space expands faster than the speed of light that
if that were the case, then the information wouldn't be
out through the whole universe, and there would be parts
of the universe without the Higgs field. But as you say,
(41:23):
we don't think the Higgs field was created just in
one place. The universe cools simultaneously everywhere. Remember, the Big
Bang is not like the explosion of a tiny, little
dense blob of matter in the early universe. It's the
expansion of the entire universe simultaneously. It happened everywhere at
the same time, and it's happening still. This expansion, this dilution,
(41:44):
this cooling of the universe, still happening everywhere. And so
we think that the whole universe cooled at once, and
this like moment when the Higgs fial was relevant probably
happened all over the universe. Now, it may have happened
at slightly different times. There were different quantum fluctuary sations
in the early universe, so some bits were a little
hotter and some bits were a little cooler. So some
(42:05):
parts of the universe probably got the Higgs field before
other parts of the universe, as we say, but what
probably wasn't a very big difference. But you're saying there
was a moment in time in the universe where there
were spots like patches of Higgs field. Some places had it,
in some places maybe didn't. Yeah, and I can remember
we're not talking about like the physical creation of something.
We're talking about the universe transitioning from sort of a
(42:26):
phase where you can talk about the Higgs field where
it makes sense, to a phase where it doesn't. And
we don't really know what those phase transitions are alike.
You know, is it like going from a solid to
a liquid where it's really sudden and in one moment
at one set of rules applies, like motion through a crystal.
In another moment you're doing fluid dynamics, or is it
very gradual, the way like gases turned into plasmas. So
(42:47):
we really just don't know what that transition is like
we do, I have no idea what the physics was
like on the other side. That's one reason we want to,
for example, build bigger particle colliders to recreate those conditions
and like see the physics and those scenarios. Does the
Higgs field still work? What kind of theory do we
need to describe super duper high energy scenarios We just
don't know. Man, you just have to work in a
(43:08):
commercial for your job, like more funding to find out
the answer. Look, if we're talking to supervillains that have
the capacity to build planet busting black holes, and yes,
I'm going to pitch of twenty billion dollar project. Excuse me, great,
But yeah, you know, I was thinking that the universe
sort of all cooled everywhere at once, and so maybe
there was a time from what we know that there
(43:31):
were patches of Higgs field or no Higgs field. But
now as what we know what we can see, it's
all pretty cool down and everywhere that we know has
the Higgs field. Yeah, everywhere in the universe, the big
variations of temperature from here to the center of the Sun,
for example. But we think that all those places are
still described by the same physics where the Higgs field
is important. So we think that there's the Higgs field
(43:52):
all the way through the whole universe as far as
we are aware. I guess we have to add that
caveat like it's there as far as we know. It's
as far as the observable universe, right, Like they could
be that maybe our observable universe is in a patch
of cooler universe, and there might be patches of horder
universe elsewhere without a Higgs field. Yeah. If past the
edge of the observable universe it's really hot and dense,
crazy with hamsters eating French fries, then possibly the Higgs
(44:15):
field does not apply. Yeah. Wow, So I guess the
answer for Alex is that there are no patches of
no Higgs field as far as we know in the
observer world universe. But you know, who knows what's out
there beyond the observable universe, That's right? Who knows what
those hamsters are dipping their French fries into mayonnaise, ketchup
ice cream, some weird combination. They're crazy and no coincidence.
(44:37):
Both hamsters and Higgs started with an age, So I'm
sensing some sort of connection here. Maybe that's right. Maybe
it was a hamster field all along, that's right. Yeah,
twist ending called en Knights Shimelan, that's right. It's not
about the journey, it's about the hamsters you made along
the way. Al Right. Well, I think that answers Alex
and Ward's question. There might still be parts of the
(44:59):
universe without a field, in which case nobody has any
mass there, and so you can eat all the French
fries you want. That's right, you have the physicist approval
to eat all the French fries you want. No, technically speaking,
if there are portions of the universe too hot for
a Higgs field to apply, that we have no idea
what mass even means out there, So be careful and
stick to your diet. All right. Well, that answers all
(45:21):
three listener questions. Thanks again for sending in your questions
and sharing your curiosity with us and with everybody else. Yeah,
we think that everybody should be asking questions about the universe,
and everyone's questions deserve answers. So don't be shy. Unleash
your intellect upon the cosmos and wonder if things fit together,
if things make sense to you. Because you might ask
(45:42):
a question that cracks open everything. You might ask a
question that breaks the hamster wheel off the universe. Well,
thanks for joining us. We hope you enjoyed that. See
you next time. Thanks for listening, and remember that Daniel
and Jorge Explain the Universe is a production of I
(46:05):
Heart Radio or more podcast from my heart Radio. Visit
the i Heart Radio app, Apple podcasts, or wherever you
listen to your favorite shows. Ye
Hey, Daniel, I've been thinking about black hole. Watch out.
That's a real rabbit hole. Yeah, I'm definitely stucked in.
But here's my question. Can you make a black hole
out of anything? Like? Even rabbits? Theoretically you can, but
that's a lot of rabbits. But you don't actually need
a lot of rabbits, right, Like you can just take
a few rabbits and squeeze them together a lot, right,
(00:29):
as long as they started a release of liability, I
suppose anything is possible. Well, I got their pop prints.
I think that counts right, But I guess my bigger
question is does that mean you can make a black
hole out of anything? Yeah? I think so, even dark matter? Yeah,
anything with energy? About a black hole out of photons? Absolutely?
And you know the truth is, I'd rather you sacrificed
(00:50):
photons than rabbits. What if they're light rabbits. I am
or hammy cartoonists and the creator of PhD comics. Hi,
(01:12):
I'm Daniel. I'm a particle physicist and a professor at
UC Irvine, and I'm at least forty seven rabbits. You
wave forty seven rabbits or you own forty seven rabbits,
or you are forty seven rabbits in the costume of
a human. I think philosophically, I'm somewhat equivalent to forty
seven rabbits and intelligence, civil arm or ability to eat carrots. Yeah,
(01:34):
you know, you link two rabbit brains together, you get
something which is much smarter than just two rabbits. So
now you have forty seven rabbits. It's like rabbits to
the power. Oh my goodness, that is one massive bunny brain.
But anyways, welcome to our podcast, Daniel and Jorge Explain
the Universe, a production of I Heart Radio in which
we apply our human brains and our bunny brains and
(01:54):
our hamster brains to the deepest and biggest questions of
the universe. We don't hold. We tackle questions like how
did the universe get here? And where is it going?
What's it made out of? And how does it all work?
Because we think the universe is comprehensible. We don't know why,
but human brains have somehow managed to chisel into the
mysteries of the universe and gain little shards of understanding.
(02:17):
And our goal on this podcast is to take those
and explain all of them. To you, as well as
the deepest, biggest open questions that remain for humans and
bundies to unravel. Yeah, because it is a pretty mysterious
universe full of questions and things that we have yet
to discover, from what is most of the universe made
out of to what is the fundamental units of space
(02:40):
and time and matter in this cosmos? Or is there
even a fundamental unit of space and time in this cosmos?
Or is it just rabbits all the way down? One
of my favorite things about asking questions of the universe
is that anybody can do it. You look around you
in this weird, wild, crazy, violent, do full universe, and
(03:01):
so many things are puzzles. So many things beg you
to ask questions about them. Yeah, daniel A re allowed
also hair brained questions was in Rabbits. Sorry, I just
had to get that in because I realized after we
had our earlier exchange that that was such a little
hanging fruit for a pun and a joke. I know,
I can't believe you didn't hop up to that joke earlier.
I'll keep my ears out for funnier jokes, But yeah,
(03:23):
it is an interesting universe full of questions. And full
of inquisitive minds with questions about the universe, because I
think we all look out there into the cosmos, into
the night sky, and we look at ourselves, and we
we gotta wonder, like, what's going on? How does it
all work? What's it all made out of? That's right,
and we are not the only ones actually thinking about
the overlap between cosmic questions and small furry creatures. Last
(03:47):
night I got a fun question over email from a listener,
Evan Cleave, who wanted to know something deep and important
about the universe. But really, what was the question? Well,
I have to read it to your word for word,
because otherwise you won't believe it. It says how Low Daniel.
I have a very serious and important question. How many
hamsters floating in space would it take to have enough
(04:08):
mass to come together gravitationally to achieve nuclear fusion and
become a star? The world needs to know. Well, that's
the kind of world I want to live in, where
everybody needs to know how many hamsters you need to
make a hamster sun? Is that what you would call it?
A hamster star? A hamstar, a hamstar exactly? Yes, But
(04:29):
I swear that we had written this cold open about
rabbits and black holes before we got this important question
from Evan about hamsters and stars. It just goes to
show you how there's some sort of connection between rodents
and massive space objects. Science needs to probe this a
little more deeply. I think, Yeah, who knows how many
flying hamsters are there are out there in space? Right? Like,
(04:51):
we literally don't know. There could be a lot that's
true beyond the observable universe. It could be just all
hamsters to the edge of the universe. Most of the
universe could be hamsters. You're saying, yeah, we could be
living in a hamstar. We don't know. I think we're
all hamstars. Really, it's a pretty hammy podcast for sure.
Do you have an answer? Did you calculate how many
(05:12):
hamsters you need to achieve fusion or is that even possible?
Can you make a star out of hamsters? Oh? I
have an answer, and you know, given the urgency and
clear importance of this question, I cleared my afternoon and
shared an emergency task force just to address this question.
I pulled in international experts of planetary scientists, fusion professors,
hamster owners, you know, and we've met for an entire afternoon,
(05:34):
did some calculations, and you know, essentially to make a
star that achieves fusion, all you really need is enough stuff.
You get enough mass together and gravity will pull it
together and create the conditions you need for fusion. And
the minimum threshold there is about eighty times the mass
of Jupiter, which is about one point six times ten
(05:56):
to the twenty nine kims. So it's a big mass. Wow.
I'm glad that was a productive afternoon and you didn't
just sit there spinning your wheels in a hamster wheel. No,
I didn't just weasel out of this question. I really
took it seriously. But you're saying that if I had
an eighty jupiter's worth of hamsters, it would become a son.
It would become a son. Now, technically that calculation is
(06:17):
done assuming that you have eighty jupiter's worth of hydrogen,
and you know, hamsters are made of heavier elements. That's
carbon in there other stuff. But mostly the same calculations
will work. Really, you can, like, if you had, you know,
eighty jupiter's worth of carbon, it would turn into a star.
That's not necessarily the same, is it. It's not exactly
the same but approximately as long as it's lighter than iron,
(06:39):
then gravity can do its thing and compress it. It
won't burn for nearly as long as a massive hydrogen will,
but carbon and oxygen will still fuse, and you'll get
further up at the periodic table. I see you need
gassy hamsters, not iron hamsters. You can't have tony star hamsters.
That wouldn't work. Hamster iron man would be a different.
(07:00):
So you need about eighty Jupiter's worth of hamsters to
ignity hamster. That's right. And since hamsters are about thirty
grams each, averaging over the various kinds of hamsters, that
means it requires about five times ten to the thirty hamsters.
That's five point three million YadA hamsters. M that's a lot.
(07:21):
You know, you'd be counting them and then you'd be like, YadA, YadA, YadA.
It's a YadA hamsters for sure. All right. Well, um,
I guess that's good that there aren't hamidy hamsters on Earth,
because then we'd be toast or the hamsters would literally
be on five. Well, those are the kinds of questions
you get on the internet, and Daniel, you get those
a lot, right, and you always answer them. That's right.
We answer every question you send us, the serious ones,
(07:42):
the deep ones, the silly ones. We write all our
listeners back because we think that science is just part
of being human and we want everyone to get to participate.
So if you have a question about the nature of
the universe or how many rabbits it takes to form
a black hole, please write to us to questions at
Daniel and Jorge dot com. Yeah, and Daniel always ask
(08:04):
for this emails. But sometimes we answer those questions here
on the podcast live in front of thousands and thousands
of people. Yeah. Sometimes people ask the question and I think, oh,
I bet a lot of folks would have that question,
let's dig into it on the podcast, or it just
sounds like a lot of fun, and so we select
some subset of those questions to be explored right here
on the podcast. Yeah, so today we're gonna go full
(08:26):
hamster on three pretty interesting questions we got over the
internet about electrons and when they radiate light, about the
curvature of space and equals mc squared, and also about
the Higgs field and how long has it been around.
That's right, and these are just questions from people being
curious people trying to fit together their pieces of understanding
(08:46):
into a larger mosaic so they can have in their
minds the entire universe. And when two pieces don't quite
fit together or don't give you that satisfying click, that's
when you're doing physics, when you're applying your knowledge and
trying to understand the whole universe at once. So if
you get stuck in that situation, please write to us
so to be on the podcast. We'll be answering listener
(09:12):
questions number seventeen. So we've done seventeen of these listener
questions podcast, Daniel, that's about something like fifty something listener
questions we've answered live. Yeah, that's right exactly. And I'm
really glad that the listeners get to hear their questions
get answered, and they get to participate in the science
process because this right here, this is science happening. I
(09:33):
feel like you just demoted science, Like if this counts
as science, it's a big tent, man, it's a big,
big tent. We're way in the outskirts of the tent,
like halfway in getting wet on one side of our body.
I'm not about science gates keeping man science is for everyone.
All right, Well, let's crash the gates and let's go
full science here and well, the first question will tackle
here is from Tim who has a question about electron radiation. Hello,
(09:57):
Daniel and Johe love podcas casts. You're doing great work.
While discussing a listener question, you mentioned that electrons moving
up and down antenna generate photons. That sent me down
a Google rabbit hole where I found that syncotron's use
electrons going around in a circle to generate X rays.
Similar concept, but it got me thinking why do electrons
(10:21):
bound to atoms going around in a circle not produce
photons as well? Can't wait to hear the answer and
look forward to hearing from you. Keep up the good work.
All right, thank you for that awesome question. I'm not
quite sure I understand the question though, Daniel. The question
is about when electrons give off light, and we did
a fun episode with listener questions where we talk about
(10:43):
essentially how electrons make photons. Like, somebody asked how you
get an electron to shoot off a photon? What makes
that happen? And when answering that question, we explained that
the way you get an electron to radiate is essentially
you accelerated, you wiggle it like the pick. Sure I
have in my mind is that the electron is surrounded
by an electric field. An electronic tracts positrons and it
(11:07):
repels other electrons, and it does so using its electric field.
So it's electric field sort of fills space around it.
What happens when you wiggle that electron is that the
electric field also wiggles. Is like a ripple in that
electric field isn't change instantaneously, and so that's what we
call a photon. So the answer we gave there was
that to generate a photon, to get an electron to
(11:29):
radiate a photon, to shoot off a little piece of light,
all you have to do is accelerated. But his question is,
what about electrons and atoms? Aren't they moving in a circle,
which is acceleration, So why aren't those electrons just shooting
off photons all the time? Right, Okay, I think I
got it. So you're saying electrons generally, if you wiggle them,
(11:50):
if you accelerate them, they give off light. And then
is that just electrons or anything that you know electromagnetic,
anything that has electric charge will give off a photon
if you accelerated, so amuan or any other particle that
has electric charge, if it accelerates, it will give off
a photon because it's acceleration changes the electromagnetic field and
(12:11):
the information moving through that field. That's what a photon is, man, right,
And then it loses some energy or is it always
just giving off photons in every direction forever? No, it
loses some energy exactly. That's how an electron essentially breaks. Right.
An electron changes direction by like pushing off a photon
in the other direction. Like, how can an electron turn, Well,
(12:31):
the only way for it to like change its trajectory
is the same way you would in space, which is
throwing something out the back. An electron turns in space
changes direction, which is essentially acceleration by tossing a photon away. So,
for example, if you want electrons to move in a
circle the way we have and some accelerators like singletrons,
for that to happen, electrons have to constantly be radiating
(12:54):
off photons to push them in the circle. And you're saying,
that's kind of how antenna work, because there's electrons wiggling
inside of an antenna, and that gives off the photons
and the electrical signal. Yeah, in both directions. You can
generate photons using electrons by taking them and using current
from your signal to wiggle the electrons, and that generates photons.
(13:17):
And that's exactly what an antenna is. That's how, for example,
those tall towers from radio stations generate radio waves as
they have like electrons moving up and down those antennas,
and the frequency of the electrons motion is the frequency
of the photon that they generate. It's very simple and
direct connection between the motion of the electron, the motion
of the electric field that it's connected to, and the photon,
(13:39):
which is just wiggling of that electromagnetic field. All right,
So I guess the question is that if a wiggling
electron gives off a photon, then wouldn't electrons wiggling around
an atom also be giving of photons all the time? Yes,
And it's actually a really deep and important question about
how atoms were and something that people struggled with for
(14:02):
decades in the early part of the century because remember
that the first picture of atoms, and the one that
Tim describes, is sort of of electrons moving around the
nucleus like in a little orbit. The sort of Neil's
bore picture of the atom was that it was sort
of like a little planetary system. You have these electrons
whizzing around like little classical objects, like tiny little balls,
(14:24):
moving around in a circle around the nucleus. And if
that were true, if electrons actually were moving in those
little circles around the nucleus, they should be radiating, they
should be losing energy, should they should be giving off photons,
And if they would, then they should just fall right
into the nucleus and they should collapse. So if you
do the calculation, is suggests that like the hydrogen atom
should only last for like ten to the negative twelve seconds.
(14:46):
But of course we see that hydrogen is stable. Electrons
can hang out in these atoms and they don't collapse
and tend to the negative twelve seconds. So this was
a big puzzle in physics, not just for tim but
for like the brightest minds in physics for many years. Right,
because that's the classical view of the atom. Right, It's
like you imagine, or you draw a little dot, and
then you draw some electron dots like whizzing around in
(15:08):
like elliptical orbits around the nucleus of the atom, right,
And so if that picture is true, then you're saying
that that would not be sustainable because you know, the
electrons are moving in a circle, which means we're accelerating
and decelerating, and that means that they should be giving
up light all the time exactly. And this is just
what I was talking about earlier. You like take your
(15:28):
understanding of something and you apply the rules to you said, well,
if this picture is true, then why doesn't this happen
or why doesn't that happen? Right? That's the core of
doing physics, of doing science, of trying to link together
all of your understanding and make sure that it all
like fits together in a way that makes sense, because
you shouldn't have different rules for different situations. And so
that's the fundamental question that Tim is asking is why
(15:50):
doesn't the electron essentially collapse into the nucleus instantaneously? M alright,
So then what's really going on here? Why don't the
electrons moving and on the nucleus of the atom give
up light? The reason is that they are not really
little classical objects. They're not really tiny little balls in
orbits that are moving with circular motion the way that
we imagine them in that picture of the atom. They
(16:13):
are fundamentally very, very different and strange objects. There are
quantum mechanical objects that don't have a path. Like an
electron is not like a tiny little object that really
is moving along some path in space and time. We
just don't know exactly what it is. It doesn't have
a path, that doesn't have a well defined location as
(16:34):
a function of time. It's a quantum object. It's fundamentally
very different, right. I think you're saying that the electron
orbiting around the nucleus of the atom is not really orbiting, right,
like the center of mass or the center of the electron.
It's not really like going in a circle. It's more
like kind of stationary, right, Or it just has sort
of a mathematical equivalent of orbiting. Yeah, it's not even
(16:56):
really mathematically equivalent to orbiting. It's like not really orbiting.
Act all. The way to think about it is not
as a tiny little grain of matter in motion around
the nucleus. It's something really totally different. It's a quantum object.
What you should think about is that the electron is
a tiny little packet of energy you know, just the
same way the photon is a little packet of energy
(17:17):
in the electromagnetic field. The electron is a little packet
of energy in the electron field. So what you should
think about it instead is like a little blob of stuff.
And as you said, it's in a stationary state. It's
like in a stable configuration. It's like if you've trapped
this little thing in a container. It's just hanging out
in there. It's not actually in motion. So the best
(17:38):
way to think about this is a little pack of
energy in its lowest possible state. So then I guess
why do we always use the word orbiting and like,
you know, when we talk about electrons and then the
end we always say, you know, the electron is orbiting?
Is it? Because it's sort of like an analogy, you know,
like an orbit is kind of like a stable energy level. Yeah.
(17:58):
I think we probably shouldn't use the word orbit because
it's very misleading, but I think it's historical. It shows
the sort of the development of our thinking. We've started
from a classical idea and we've been gradually moving more
and more towards these quantum ideas. So now we talk about,
you know, orbit tolls which represent like energy densities. Still
that this sort of suggestive because you're suggesting the electron
(18:19):
has a location, it just has like a probability to
be here in a probability to be there, when really
the location of the electron and its motion is not
well defined until something actually interacts with the electron. And
so often these classical analogies are easier to understand, but
they're often misleading as well. All right, well, then it
sounds like the answers to the question is that electrons
(18:41):
in atoms don't radiate photons because they're not really accelerating, right,
they're not really moving, and so nothing would sort of
prop them to shoot off a photon. That's right, and
sometimes they do shoot off a photon. Remember that there
are electrons in like higher energy states. There's a ladder
of states there, and if you're in a higher energy state,
then you can actually move down onto a lower energy state,
(19:01):
and the way you do that is you shoot off
a photon. So, for example, anytime you see a gas
that's like glowing, you know that's gas that's been energized.
The electrons have extra energy and they give off photons
and go down to a lower energy, but most atoms,
the electrons are at their lowest energy level. And one
really interesting thing about quantum objects like an electron is
(19:21):
that they have a minimum energy level. Like the electron
can't go into the nucleus. They can't like settle down
to a zero energy state, because there's a minimum energy
to every quantum field. This is called the quantum zero
point energy. So the electron can't collapse into the nucleus
because it's already at the lowest possible energy level. I see.
All right, So then electrons and atoms can radiate photons,
(19:44):
but it's not because of the wiggling or the exploration.
It's because they jump from one energy state to another. Yeah,
all right, Well, hopefully that answer is Tim's question, and
so let's get into our two other questions for the episodes,
one about the curvature space and the equals mc square
and the other one about the Higgs field and whether
or not we can live without it. But first let's
take a quick break. All right, we are answering listener
(20:17):
questions today, and our next question comes from Pete, who
has a question about energy and the curvature of space. Hi,
Daniel and Jorge my name is Pete. I have a
question about spacetime curvature. According to the general relativity, we
know space curves in the presence of matter or energy density.
But can we detect the curvature of space or ripples
(20:40):
in spacetime from just energy density alone and not through
the effects of matter like black holes and neutron stars
and stuff. Given that E equals mc squared, you would
think that energy has tremendously more influence throughout the universe
than just matter. But can we detect gravity waves from
things like supernova or quasars? Thanks very much, I love
your podcast. Awesome, Thank you, Pete Daniel. I feel like
(21:02):
I need an episode that explains these questions much less
trying to answer. I feel like I need a listener
questions questions episode about this one. You picked some pretty
tough ones today. Did you do that on purpose? Yeah?
I thought you needed a challenge. No, I just thought
these were fun. Some of these made me go off
and do some research, which is always something I enjoyed doing.
(21:23):
One of my favorite things about this podcast is that
it gives me an excuse to go off and read
about areas of physics I've always been interested in but
never had time to dig into m All right, well,
let me see if I can interpret this question. So
I think Pete is saying that we know that gravity
and mass bend space and curve space, right, and we
also know that energy does that too. So I think
(21:45):
this question is can we detect this bending of space
from just energy, because there should be a lot of
energy in the universe, especially if the equals empty squared,
because that means that the energy is much more powerful
than matter. Yeah, exactly. I think that's the question because
general relativity doesn't just say that mass bend space. Mass
does bend space, but mass is just an example of
(22:06):
the category of stuff that can bend space, which is
anything essentially with energy density. And it's actually, for those
general relativity nerds out there, a little bit more complicated.
There's a stress energy tensor, so it's also dependent on
how that stuff is arranged, but it's close enough to
say that anything with energy can change the shape of space,
and not just matter. Matter is an example of energy.
(22:28):
So I think his question is why don't we see
space being bent by energy because equals mc squared suggests
that energy should be super powerful in the universe, right,
meaning like, if I see a neutron star giving off
a lot of light, do I see space bending because
of all that light coming out of it? And I
think it's useful to sort of dig into the second
part of his question first, like this question, but E
(22:49):
equals mc squared and what that means. It's certainly true
that mass contains a lot of energy. Right, equals mc
squared means that mass is very dense with energy because
the C squared is a big number, right, ce is
the speed of light, which is three million meters per second.
So you take a little bit of mass and you're
multiplied by a big number squared to get how much
(23:12):
energy is stored inside that mass. And we know that,
for example, because you can make like a huge bomb
with a tiny little bit of fuel by getting that
energy out of mass. That's how nuclear weapons work. Right,
So we know that mass is very very dense with energy, right.
And I know from our conversation is that basically you
can also say that mass is just energy, right, or
(23:33):
in a way, mass is just like a measure of energy. Yeah,
So it's all sort of the same thing anyways, Exactly.
That's the point I want to make, is that what
is that mass anyway, It's really just the energy inside
the object. Like most of your mass doesn't come from
the stuff that makes you up, the little corks and
the electrons. It comes from the energy of those objects
being held together. So your mass, how much your bending
(23:56):
space is actually just from your internal energy. Like the
bond between your objects is what gives you mass and
helps you bend space. So even if you're just looking
at a neutron star or a black hole, the reason
it has mass is because it contains a lot of energy.
So basically, every time you're seeing space bend, it's just
because of energy. Right. Well, I think most of my
(24:17):
mass comes from French fries. But there's a different topic altogether.
I don't think there's a term in Einstein's equation for
French fries, but maybe you should have added one. Well,
he was German, so I think he's worn too sausages
or something. What is the French friese density of the
universe anyway, another deep question of physics we can't answer.
I mean, French fries do you need to make a star?
(24:37):
I don't know your star. How many French fries have
you eaten? That's probably more than the number of hamsters
in the universe more than the number of hamsters you've eaten.
I hope somethings that even with him. Then then we
get a black hole. But I think what you're saying
is that mass is energy, and so you know energy
is causing the bending of space out there. But I
think maybe Pete's question is born like can we see
(25:00):
the bending of space just from energy that's not associated
with mass, right, because there is energy that's not related
to mass too, right, Yeah, there is absolutely. Like you
take a photon, A photon is just energy. It has
no mass, right, So lots of radiation can be massless,
like gravitational waves are also a form of radiation. They
(25:20):
have no mass, but there's a lot of energy there.
And so I think his question really is like, can
you just take photons or gravitational waves massless energy and
use that to bend space? Whoa wait, so it's not
a gravitational wave was a bending of space. You're saying
that the bending of space can cause the bending of space. Yeah. Absolutely,
That's the crazy thing about gravity that's sort of nonlinear
(25:42):
that way, right, sort of keys off of itself, and
that's one of the things that makes it so difficult
to develop a quantum theory of gravity, like gravitons would
interact with other gravitons, and you know the way that
like photons don't write, photons don't interact with other photons.
That's one reason why electromagnetism is easier to calculate and
think about, and then other theories like the strong force
(26:04):
where gluons interact with other gluons or gravity where things
get nonlinear for similar reasons. M M all right, Well
then Pete's question I think is can we detect the
bending of space from just photons and or all that
energy flying around the universe or is that somehow in
a different category of space bending. Yeah. I think there's
two different answers here. One is like is it possible?
(26:25):
Could you do this? And the other is like why
don't we see it more happening in the universe today?
And to answer the first one, we think that you
could in principle, if you took enough lasers that were
powerful enough and you focused them on a single point
so you overlapped huge number of photons in a tiny
little space, then you would create a black hole. Mmmmm wait, wait,
(26:49):
if you shoot enough photons into one space, you might
create a black hole. That sounds crazy, right, nobody would
ever try to do that. Would day supervillains out there?
Take note in your layers underneath volcano. We are giving
the prescription today for how to create a black hole.
At the Large Hadron Collider, we shoot protons together a
very high energy. The idea is the same. If you
(27:10):
have enough energy in those collisions, you might have enough
energy density to create a miniature black hole. Same idea
with photons, just different kind of particle. If you build
enough big lasers and overlap their beams in one tight
little spot, you could create a black hole. That people
have done the calculation, and you'd need to have like
a single laser pulse have the same amount of energy
(27:32):
that the Sun produces in a tenth of a second.
So we're not talking about like the kind of lasers
that humans can build currently. We're talking about like enormous
alien terra scale projects lasers to build a black hole.
Oh wow, Well, first of all, I feel like you
just admitted to being a supervillain, Daniel. No, no, no,
I'm a consultant for supervillain. Isn't that what all these
(27:52):
listener questions are really about you're just a betting the
villains right for money. I'm just a scientist answering hypoth
medical questions about how to build a Doom's Day device.
That's all. That's right. You're just asking for a friend
while stroking a cat in their lap, all right. So
it is possible to bend space with just energy, with
just photons, and you can even make a black hole
(28:13):
if you overlap enough photons in one spot. Now, the
other part of Pete's question was why don't we see
more of that in the universe, because like there's a
lot of light in the universe, there's a lot of
you know, radiation being admitted and sing everywhere. Do we
see a general bending of space from that energy? So
the answer is that radiation does contribute to the overall
general bending of space. Like when we measure the curvature
(28:35):
of the whole universe, we measure how much energy density
there is, like per volume, and that affects the whole
bending of space. And part of that budget is radiation
is like includes the photons and the gravitational waves and
all the other kinds of radiation that are in every
unit of space. So the answer is Yes, that happens,
and we can measure it. We can measure the radiation
(28:57):
component of the universe, and we know it does contribute
to the bending of space. But there isn't very much
radiation in the universe. Like if you look at the
pie chart of the energy budget for the universe per
like unit of space, it's mostly not radiation. Most of
the energy in the universe is dark energy. Some other
fraction of the energy and universe is matter. Very very
(29:21):
tiny sliver of the energy of the universe is in
the form of radiation. So it's there. It contributes, we
can measure it, but there's just not very much radiation
in the universe right now. I see. So you're talking
about like a specific type of energy, which is like
light or radiation. You're saying, that's a pretty small percentage
of the matter and energy, right except the non dark
(29:44):
energy stuff in the universe. Yeah, exactly what you have
to include the dark energy. Dark energy also contributes to
the overall curvature of the universe. And you know that's
super interesting, Like we have just about as much energy
per unit volume as you need the universe to keep
the universe to be flat. So the overall curvature is
basically zero. That's something we don't even really understand very well.
(30:05):
All the energy adds up to like exactly the right
number to make the universe have like flat curvature, which
is weird. But photons and gravitational waves and other kinds
of radiation are a tiny little sliver of that. But
the interesting thing is that that didn't used to be
the case. There was a time in the history of
the universe when radiation dominated the energy budget right at
(30:27):
the beginning of the universe, right, that's right, very early on,
the universe was like crazy lousy with photons, Like photons
were everywhere. It was mostly photons. They were bouncing around,
they were being created. The place was hot and dense.
So the first like fifty thousand years of the universe
we think was radiation dominated. Then of course things cooled down,
(30:48):
and when things cooled down, that radiation turns into matter
and then doesn't oscillate back into radiation. So for example,
a photon whizzing around becomes an electron and oppositron, and
maybe those guys go off in opposite directions and don't
recombine to make an electron. And because the universe is
cooled and more dilute. There aren't like other particles for
them to annihilate into, so instead of matter and antimatter
(31:11):
annihilating each other, they just sort of like go their
own ways. And then we have the universe being matter
dominated for like ten billion years, So the universe was
radiation dominated, but only for a very short while in
the early universe, right, I think you're saying that right now,
like where we are now in the history of the universe,
the universe is too cool or not bright enough to
(31:33):
really see the effects of like right energy space bending. Yeah,
that's exactly right. But there is dark energy, but that's
kind of a different kind of energy, Like we don't
love dark energy in with all of the other types
of energy. Yeah, exactly, even though it has the word
energy in the name. Well, it is a kind of energy,
but it's not a kind of radiation or a kind
of matter as far as we know. So if you
(31:54):
have those categories, dark energy is most of the energy,
and the universe is like the rest of it is
matter and radiation, but of the matter and radiation portion,
most of that is matter. So yeah, there is radiation
in the universe, but it's a tiny sliver, and the
history I think is super fascinating. In the first fifty
thousand years it was all radiation, then the next ten
billion years was matter dominated, and the last four billion
(32:17):
years or so have been dark energy dominated. So we've
seen like these different phases of time where different components
are dominating the energy budget of the universe, until we
expand our serviable universe, and then it's hamster dominated universe. Right,
the hamsters belong in the matter of category, the radiation category,
or are they their own kind of energy? All of
(32:38):
the above. It's a hamster powered universe or none of
the above. It's right, We're all just the giant wheel
spinning because of the hamsters. Feels like it sometimes. All right, well,
I think that answers Pete's question. Can we detect the
curvature space from just energy? And the answer is yes,
But right now it's pretty faint, although it used to
be much more significant. So let's get into our last
(32:59):
question of the EPISO. So this one's about the Higgs
field and whether or not we can live without it.
So let's get into that. But first let's take another
quick break. All right, we're answering listener questions, and we're
(33:22):
at our last question of the episode. This one is
from Alex and Ward from Belgium, who are a father
and son question asking team, or maybe they're a hamster
and rabbit, but who knows talking hamster and rabbit. Do
you think they're eating French fries, Daniel or Belgium fries?
What do they call them in Belgium? I think they
call them palm freed. And if they're eating them, they're
(33:43):
probably eating them with mayonnaise, which is awesome. I am
definitely in the mayor with fries camp. What about you?
Oh my god, are you serious? Wow, We're gonna have
to revaluate his entire friendship. Yeah, I love it. And
if that's the end of our friendship, then I'll stand
by that line in this thing. It's delicious. Mayo is
delicious and basically everything I like mixing them together. Actually
(34:05):
a little mayo, a little catch up. I think you're
a magic thought. That's right. I mixed the light and
the dark sides of the force, the matter and the
antimatter of condiment. All right, Well, Alex and White have
a question about the Higgs Field. Hi, Daniel and j
you'r Alexander and what's two huge fans from Belgium. We
(34:26):
love your book and podcasts. Alexander, who is twelve years old,
read in a science magazine that the Higgs field was
created sometime after the Big Bang, and you asked me
the following question about us. If the universe started expanding
at at a big bang, and the Higgs field was
created after the Big Bang, and the information cannot go
(34:46):
faster than speed of light, and the expansion of space
goes faster than light, then shouldn't there be a place
in the universe where there's no Higgs field even today?
A really hard question and I really have no maybe
you can help, thank you. All right, I agree, it's
a pretty tricky question, and I'm glad we're here to
(35:08):
answer father's questions. Should we tackle purity next? And that's right.
We are the backup parents online and the Birds and
the Bees and the Hamsters. I think that's a different
podcast though, we should, you know, stick to our specialty. Yeah,
you should go listen to Creature feature for that one.
All right. Well, the question I think here is I'm
trying to wrap my head around it because it's it's
(35:29):
a little tricky. I think I think he's saying that
if the Higgs field was created after the Big Bang,
shouldn't there be a part of the universe with no
Higgs field, Because I think he's thinking that maybe there
was a big emptiness, or there was larger universe, and
somewhere in the middle there was a big bang which
started the creation of the Higgs field, and so shouldn't
there be parts of the universe without the Higgs field.
Do you think that's what's going on in his head. Yeah,
(35:50):
I think that's the question. And so there's a bunch
of interesting stuff there, like this idea that the Higgs
field is created after the Big Bang and where it
was created and then how it spreads out through the universe.
Has a bunch of fun ideas there to disentangle. All right, Well,
let's recap really quickly. What is the Higgs field in
the first place. Yeah, So the Higgs field is this
thing we discovered about ten years ago. We suspected it
(36:14):
existed for like fifty years, but it only found confirmation
at the Particle collider in twelve. And if a field
that we think fills the whole universe and interacts with
particles in a way, that gives them mass. So the reason,
for example, an electron doesn't have zero mass is that
it flies to the universe and interacts with the Higgs field,
which changes the way it moves so that it looks
(36:34):
like it has some inertial mass. It means that it
takes a force to push the electron to speed it up,
or also forced to slow it down. So the Higgs
field affects how particles move in a way that gives
them mass. Cool, and we knew about it for a
long time, but we discovered that recently. So that's the
Higgs field. But what does it mean that it was
created after the Big Bang? Like it wasn't always there,
(36:57):
or was it there but not active? This is actually
a really anxiest and deep question that goes to like
how we think about our physics. You know, we are
trying to find the deepest rules of the universe. We
think that maybe, as you were saying before, there are
like fundamental rules to the universe, like the equations that
cover everything. Now we don't think we have found those equations.
We have a standard model of particle physics that works
(37:19):
really really well, but we don't think that the equations
we have are like the ones that are really fundamentally true.
We think the equations we have sort of work for
the conditions that we have studied, and we don't think
that they're like the deep and true equations. So what
that means is that the laws we're talking about, including
like the existence of the Higgs field, are really just
like effective laws. It's sort of like if you are
(37:40):
living in ice and you've been studying the way ice works,
the crystal structure of it, and how it moves, and
how energy moves through it. The laws of how the
ice works are not like fundamental to the universe. They're
just descriptions of how the ice works, the physics of
that ice. And so in the same way, we suspect
that the universe used to be hotter, used to be denser,
and so it's effectively different laws of physics were at play.
(38:03):
So when we say the Higgs field was created, what
we really mean is that the universe cooled down to
a point where it makes sense to talk about the
Higgs field. Where the Higgs field is like a useful
mental idea for doing physics. I see, It's just we
don't know if the Higgs field is a fundamental thing.
You're saying, like there may be like higher laws or something,
But at least from what we know and what we
(38:26):
can see around, the Higgs field is a pretty good
description of what's going on. But that's not always the
case exactly. We're pretty sure that it isn't the case. Like,
if you try to take our theories and apply them
to really really crazy scenarios at the very beginning of
the universe, they just don't work. So we're pretty sure
that our laws, including the Higgs field, are not the
true laws of the universe. They're just the ones that
(38:47):
we have found that describe the situations we've been able
to explore. So if somebody says the Higgs field was created,
I think that's a little bit misleading. What they really
mean is that the universe cool to a point where
the Higgs field makes sense as a way to think
about the universe. M But I guess the weird thing
about it is that the Higgs field feels really fundamental, right.
It gives things mass. So does that mean that at
(39:09):
some point we didn't have mass? It like mass didn't
make sense in the universe. It could be It could
also be that there are just different rules, different ways
to get mass, or it could be like mass is
not an important concept. You know, everything that we're talking
about in the universe, we don't know if they are fundamental,
like essential elements of the universe or just emergence stuff
that like comes out of the complexity of the universe.
(39:32):
And you know, that's easy to think about for some things,
like for example, we have ice cream in the universe.
Ice Cream feels important, especially in a hot summer, but
it's not fundamental. You can imagine there could be universes
without ice cream, right, no big deal. Well, I beg
to different Daniel, what's the universe without ice cream? It
might not be worth living in. But you know there
are other things to difference rise into. But you can
(39:53):
also think that same logic and applies to other things
in the universe, like the Higgs field or even like
space it's self. Right, we talked in the podcast about
whether space itself is actually fundamental to the universe or
if you could have a universe without space. And we
physicists feel like, well, we don't really know the true
nature of the universe. We've just been studying this one
particular slice of the universe in a certain energy range,
(40:16):
a certain temperature range, because that's the one we live in,
and we know that our theories we try to do
calculations don't work at higher temperatures, and so we suspect
that some of the stuff that seems fundamental is actually
just emergent. It's just like an interesting property that comes about,
but isn't like deeply true about the universe. I guess,
going back to Alex's question, you're saying that the universe
(40:39):
at some point cooled down enough to where the Higgs
field came into effect, basically, and so I think his
question is like, did that happen everywhere at once or
did the universe sort of cool differently in different places,
and so what does that mean? Or is it cooling
right now in different places differently. So it's that there
are spots with the Higgs field and spots without the
Higgs field. Yeah, that is a really cool question. I
(41:01):
think the origin of his confusion is that he imagines
that the Higgs field was created in one place and
then would have to spread out through the universe. And
he's right that because information travels at the speed of light,
and space expands faster than the speed of light that
if that were the case, then the information wouldn't be
out through the whole universe, and there would be parts
of the universe without the Higgs field. But as you say,
(41:23):
we don't think the Higgs field was created just in
one place. The universe cools simultaneously everywhere. Remember, the Big
Bang is not like the explosion of a tiny, little
dense blob of matter in the early universe. It's the
expansion of the entire universe simultaneously. It happened everywhere at
the same time, and it's happening still. This expansion, this dilution,
(41:44):
this cooling of the universe, still happening everywhere. And so
we think that the whole universe cooled at once, and
this like moment when the Higgs fial was relevant probably
happened all over the universe. Now, it may have happened
at slightly different times. There were different quantum fluctuary sations
in the early universe, so some bits were a little
hotter and some bits were a little cooler. So some
(42:05):
parts of the universe probably got the Higgs field before
other parts of the universe, as we say, but what
probably wasn't a very big difference. But you're saying there
was a moment in time in the universe where there
were spots like patches of Higgs field. Some places had it,
in some places maybe didn't. Yeah, and I can remember
we're not talking about like the physical creation of something.
We're talking about the universe transitioning from sort of a
(42:26):
phase where you can talk about the Higgs field where
it makes sense, to a phase where it doesn't. And
we don't really know what those phase transitions are alike.
You know, is it like going from a solid to
a liquid where it's really sudden and in one moment
at one set of rules applies, like motion through a crystal.
In another moment you're doing fluid dynamics, or is it
very gradual, the way like gases turned into plasmas. So
(42:47):
we really just don't know what that transition is like
we do, I have no idea what the physics was
like on the other side. That's one reason we want to,
for example, build bigger particle colliders to recreate those conditions
and like see the physics and those scenarios. Does the
Higgs field still work? What kind of theory do we
need to describe super duper high energy scenarios We just
don't know. Man, you just have to work in a
(43:08):
commercial for your job, like more funding to find out
the answer. Look, if we're talking to supervillains that have
the capacity to build planet busting black holes, and yes,
I'm going to pitch of twenty billion dollar project. Excuse me, great,
But yeah, you know, I was thinking that the universe
sort of all cooled everywhere at once, and so maybe
there was a time from what we know that there
(43:31):
were patches of Higgs field or no Higgs field. But
now as what we know what we can see, it's
all pretty cool down and everywhere that we know has
the Higgs field. Yeah, everywhere in the universe, the big
variations of temperature from here to the center of the Sun,
for example. But we think that all those places are
still described by the same physics where the Higgs field
is important. So we think that there's the Higgs field
(43:52):
all the way through the whole universe as far as
we are aware. I guess we have to add that
caveat like it's there as far as we know. It's
as far as the observable universe, right, Like they could
be that maybe our observable universe is in a patch
of cooler universe, and there might be patches of horder
universe elsewhere without a Higgs field. Yeah. If past the
edge of the observable universe it's really hot and dense,
crazy with hamsters eating French fries, then possibly the Higgs
(44:15):
field does not apply. Yeah. Wow, So I guess the
answer for Alex is that there are no patches of
no Higgs field as far as we know in the
observer world universe. But you know, who knows what's out
there beyond the observable universe, That's right? Who knows what
those hamsters are dipping their French fries into mayonnaise, ketchup
ice cream, some weird combination. They're crazy and no coincidence.
(44:37):
Both hamsters and Higgs started with an age, So I'm
sensing some sort of connection here. Maybe that's right. Maybe
it was a hamster field all along, that's right. Yeah,
twist ending called en Knights Shimelan, that's right. It's not
about the journey, it's about the hamsters you made along
the way. Al Right. Well, I think that answers Alex
and Ward's question. There might still be parts of the
(44:59):
universe without a field, in which case nobody has any
mass there, and so you can eat all the French
fries you want. That's right, you have the physicist approval
to eat all the French fries you want. No, technically speaking,
if there are portions of the universe too hot for
a Higgs field to apply, that we have no idea
what mass even means out there, So be careful and
stick to your diet. All right. Well, that answers all
(45:21):
three listener questions. Thanks again for sending in your questions
and sharing your curiosity with us and with everybody else. Yeah,
we think that everybody should be asking questions about the universe,
and everyone's questions deserve answers. So don't be shy. Unleash
your intellect upon the cosmos and wonder if things fit together,
if things make sense to you. Because you might ask
(45:42):
a question that cracks open everything. You might ask a
question that breaks the hamster wheel off the universe. Well,
thanks for joining us. We hope you enjoyed that. See
you next time. Thanks for listening, and remember that Daniel
and Jorge Explain the Universe is a production of I
(46:05):
Heart Radio or more podcast from my heart Radio. Visit
the i Heart Radio app, Apple podcasts, or wherever you
listen to your favorite shows. Ye
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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