Daniel and Kelly’s Extraordinary Universe - Listener Questions about light and black holes
Episode Date: January 5, 2023Daniel and Jorge absorb listener questions, reflect on the answers and emit some silly jokesSee omnystudio.com/listener for privacy information....
Transcript
Discussion (0)
This is an I-Heart podcast.
From tips for healthy living to the latest medical breakthroughs,
WebMD's Health Discovered podcast keeps you up to date on today's most important health issues.
Through in-depth conversations with experts from across the health care community,
WebMD reveals how today's health news will impact your life tomorrow.
It's not that people don't know that exercise is healthy,
it's just that people don't know why it's healthy,
and we're struggling to try to help people help themselves and each other.
Listen to WebMD Health Discovered on the IHeart Radio app or wherever you get your podcasts.
It's important that we just reassure people that they're not alone and there is help out there.
The Good Stuff podcast, season two, takes a deep look into One Tribe Foundation,
a non-profit fighting suicide in the veteran community.
September is National Suicide Prevention Month,
so join host Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission.
One Tribe, save my life twice.
Welcome to Season 2 of The Good Stuff.
Listen to the Good Stuff podcast on the Iheart radio app,
Apple Podcasts, or wherever you get your podcast.
Hi, it's Honey German, and I'm back with season two of my podcast.
Grasias, come again.
We got you when it comes to the latest in music and entertainment
with interviews with some of your favorite Latin artists and celebrities.
You didn't have to audition?
No, I didn't audition.
I haven't audition in, like, over 25 years.
Oh, wow.
That's a real G-talk right there.
Oh, yeah.
We'll talk about all that's viral and trending
with a little bit of cheesement and a whole lot of laughs.
And of course, the great bevras you've come to expect.
Listen to the new season of Dacias Come Again on the IHeartRadio app, Apple Podcasts, or wherever you get your podcast.
I'm Dr. Scott Barry Kaufman, host of the Psychology Podcast.
Here's a clip from an upcoming conversation about how to be a better you.
When you think about emotion regulation, you're not going to choose an adaptive strategy which is more effortful to use.
unless you think there's a good outcome.
Avoidance is easier.
Ignoring is easier.
Denials is easier.
Complex problem solving.
Takes effort.
Listen to the psychology podcast on the Iheart radio app,
Apple Podcasts, or wherever you get your podcasts.
Hey, Daniel, I have a light question for you.
I hope I am bright enough to answer it.
See, I can tell you're taking this a little too long.
lightly. Well, you know, I'm happy to answer it and try to lighten your intellectual load.
Now, I need a pretty awesome answer here, something totally lit, as the kids would say.
All right, what is it I can illuminate for you?
All right, are you ready?
Mm-hmm.
What is a photon anyways?
That is not a light-hearted question.
But go ahead, light it up.
Unfortunately, I don't have a very enlightening answer for you.
Just light puns.
My puns are massless.
Hi, I'm Jorge I'm a cartoonist and the creator of PhD comics.
Hi, I'm Daniel. I'm a physicist and a professor at UC Irvine, and now I find myself very light on the puns.
You're a shining example in academia?
No, I just used up all my light puns, and now my
brain is like a black hole of ideas for how to make more puns about light.
You're dimming on the puns there.
Welcome to our podcast, Daniel and Jorge, explain the universe, a production of IHeart
Radio.
In which we tried to shine a bright light on the deepest mysteries of the universe.
We wonder how everything works.
We wonder why it works at all.
We wonder why there is anything.
How much of it there is and what rules it follows.
We are amazed that we can make sense of any of this incredible.
crazy cosmos that we find ourselves in, but we are appreciative that we can, and we seek to
share that little sliver of understanding with you. That's right. It is a pretty amazing
universe full of light and shiny things for us to wonder and ask questions about, like, for
example, light, or the opposite of light, like black holes, big stars, giant stars, small stars,
dark matter, all kinds of things for us to wonder about. Because it's not just a universe
filled with stuff. It's a universe filled with stuff that is sending us messages. We couldn't see
stars in other solar systems if they were not shooting light at us or sending other kinds of
particles. So don't imagine a universe out there doing its mysterious stuff in the darkness. Instead,
all the crazy dancing that's happening in the physics inside stars and inside black holes and all
over the galaxy is beaming you answers, beaming you clues at least to lead you towards answers
and understanding of the fundamental physics that would explain it all.
Yeah, the universe is bathing us with information about itself
and they have the laws that it follows to make everything work
from giant stars and galaxies to the tiny, smallest molecules and particles.
Assuming, of course, that the universe does follow laws.
Are you saying the universe is some kind of outlaw?
Some kind of criminal universe?
Does it need to go to the universe of jail?
I don't want to put a black mark on the reputation of the universe in any sense.
I think you just did.
I'm just asking questions, you know.
Oh, I see.
I wonder if Daniel Whiteson broke the law again today.
Is that the kind of question that is harmless?
Yeah, yeah, exactly.
And I'm impressed with how well the universe so far has been following laws,
or put another way, how we've been able to discover the laws the universe seems to be following.
But, you know, there is a deep and fundamental mystery there,
which is like, why is the universe following laws at all?
And is it possible to ever come up with a single law that describes everything in the universe?
That's a little bit of an article of faith in the whole process of science.
Yeah, it's a big question.
Fortunately, the universe, as you said, is bright and is full of things that shine and give off light.
And that light gets to us.
And we can use that information to figure out if the universe should be arrested or not.
And that raises another deep question, which is if the universe breaks the law, who punishes it?
Does it go to universe jail?
In what universe is that jail?
Obviously, there's a multiverse department of justice.
I'm amazed that I've never read that science fiction novel.
I think Marvel has that pretty well covered.
But a whole universe in jail.
Wow, that's quite the budget.
Now they kill universes.
Oh, man, they shut them down.
The death penalty for a universe?
That gives me the shivers.
Yeah, it's pretty.
It's called the Time Authority.
Oh, that's right.
Yeah, they do cancel whole branches of the timeline.
That's true.
Well, let's hope that never happens to us.
We are just here trying to figure out how the universe works.
We're trusting that it is following some laws and it's not putting us in existential danger
because we would like to understand how it works.
We look at all these photons that come to our eyeballs and we try to make a mental picture of how everything works.
And sometimes we're confused.
Sometimes we see something we don't quite understand.
And that, of course, leads to my favorite part of science asking questions.
Yeah. And it's not just scientists who ask questions or love to ask questions or have questions about the universe. It's everybody. We all at some point in our lives look up at the sky and think, where did it all come from? How does it all work? Why are we here? Who is it that stole my chocolate and how can I put them in universe jail? These are big questions. Basically, everybody asks in their lifetime because science is not just a process that professors can do in their offices or in their basement labs. It's just part of being human. It's just like a way to call.
Potify and systematize the natural feelings that we have of curiosity and investigation.
It's something that everybody can do and it's something that everybody is always doing as they maneuver in this world.
Yeah, all you have to do is observe the universe, think about it, and use logic to work things out.
That's basically science, right?
That's basically science.
Also drink coffee. Coffee is a big part of it, I think.
You don't drink any coffee anymore, though.
Does that mean that you don't do any science?
Well, I don't get paid for it, if that's what you mean.
It's the coffee drinking that I'm getting paid for over here.
That's true, yeah.
It's the extra mile, yeah.
When you ingest chemicals for something, that means you're a pro.
That's what goes on my time sheets.
Nine espresso's today.
Ooh, I'm getting overtime.
Overtime.
Yeah, and overclocking your heart as well.
Exactly.
And my brain.
But what we love to do is not just ask questions ourselves and talk about them,
but encourage you to ask questions.
We hope that this podcast tickles that inquisitive part of your brain
and makes you look around at your universe and think,
do I understand how this works?
Can I figure this out?
And when you don't, we want you to write to us with your questions
so we can help you understand them.
So today on the podcast, we'll be tackling.
Listener questions, light edition.
Now, is this like a low-calorie version of our usual listener question episode?
Welcome to Daniel and Jorge on an intellectual diet.
That's right.
It's all cottage cheese and cantaloupe today, folks.
So what is it, Aspartame?
We're going to give Aspartame answers.
The sweetest questions to the sweetest mysteries in science, but with no calories.
It's going to feel sweet when you listen to our answers, but don't worry, you're not going to learn anything.
Is that what we're promising here?
Or maybe we should have very heavy answers and people should do like bench press us, you know, like really.
massive deep answers to the heaviest questions in the universe.
Maybe that should be a different podcast, the heavy edition.
The fitness version.
The massive edition.
We should be playing like fitness music in the background, so everybody can be like doing
their crunches as they listen.
That might make it a little hard to talk.
Yeah, I would think a physicist would know that.
But we do love encouraging you to ask questions and to send us your questions.
If you have questions about the way the universe works or there's something that's always
puzzled you, please, please, please write to us to us.
questions at danielanhorpe.com we answer all of our emails we answer all of these questions and sometimes
we might pick your question to answer here on the podcast yeah so today we have three awesome questions
and they're all in one way or another about light kind of right or the lack thereof perhaps yeah exactly
photons what they do when they hit stuff how far they can travel and what's going on inside a black
hole as always i feel like everything comes back to the black hole one of the most massive mysteries in
science.
I feel like it's kind of the rug for physicists.
When you hit a question that you don't know the answer to, you're like, ah, black hole.
Swoop it on there.
Why didn't I answer your email?
Oh, it must have been routed into a black hole.
My apologies.
Oh, that works.
Yeah.
An email black hole.
That's how I would describe my regular inbox.
Exactly.
Once you exceed a certain number of unread messages, it just collapses.
It creates a distortion in space and time.
All right.
We'll start here with our first question, which is about photons.
and what happens when they hit stuff?
And this question comes from Matthew.
Daniel and Jorge, what's up?
I loved the episode about photons bumping into each other,
but it really got my brain spinning here,
which is not difficult.
What happens to photons when they hit my skin?
Are they just absorbed?
And turn my skin a beautiful golden brown?
What happens when they hit soul?
solar panels. Why do things heat up when they're hit by photons? What happens when photons
hit the opaque plastic cover on my little camper and I can see light through it? Do some
get through and some don't? What happens when photons hit a mirror? What happens when
photons hit rock versus water versus clouds? I think you get the point. Boy, let's really dig in.
It's going to be photonastic.
All right.
Wow, I love that question.
Yeah, that question or questions.
That was like 20 different questions there.
It was faux-tastic.
Do you think he was eating a bowl of fuh as he was thinking about these things?
Hopefully it was diet foe.
But, well, first of all, we should just say,
What's up, Matthew?
Back to you.
Let me just say how much I enjoyed hearing him spin out on this question,
realizing that there are really basic deep questions about how photons interact with matter
and everything around us.
It is really complicated.
So thank you very much for inviting us to dig into it.
Yeah.
I think he seemed to expand in his head as he was asking the question on the idea that, first
of all, light is everywhere.
It's bouncing around everything and hitting everything.
But also there's kind of a huge variety of things that light does when it does seem to hit
things, right?
Sometimes it goes through things.
Sometimes it bounces back.
Sometimes it gets absorbed.
sometimes it heats things up, right?
There's kind of a wide range of things that light does.
Yes, light is very amazing and very complicated.
And even though it's everywhere in the world,
it does react very differently to different kinds of stuff.
It's a great way to show off like the fundamental quantum mechanics of our universe
to understand all these different behaviors when light hits different kinds of stuff.
Yeah, so let's dig in as Matthew requested.
So Daniel, let's start with the basics.
What is light?
What is this thing we call light?
Yeah, so the short answer is we really just don't know.
Done.
If we don't know what light is,
then we don't know what it does when it hits other things.
Next question.
We don't know what light is in the sense that we don't have like a good intuitive analog.
I can't say it's like a beach ball or it's like a wave in water.
It's not like anything else we know.
On the other hand,
we do have a very nice mathematical description of what light does.
So we can predict very well what happens when light hits
metal or when light hits plastic or when light hits water or when light hits your skin.
We can do all those calculations even if we don't fundamentally know what light is in the sense
that we can't like translate it into something familiar. Wait, what do you mean we don't know what
it is? I thought that light was, you know, excitations or wiggles in the electromagnetic field
that propagates across the universe, right? Isn't that the idea that the universe is filled with
quantum fields and the electromagnetic force is one of them and the wiggles in it? And the wiggles in
are the photons? Yeah, that's part of the mathematical description of how light works. We can model
light as a wiggle in the electromagnetic field. And what happens to light when it hits something can be
predicted by solutions to these wave equations, which we know mostly how to deal with in lots of
circumstances like when they hit a barrier or when they go from air to water or when it goes from
air to skin. We know mostly how to solve these problems. We don't know what light is in the sense
that we don't really understand the fundamental quantum mechanics of it, like light is a wave
in the sense that it's fluctuations in this electromagnetic field. On the other hand, it also
acts like a particle because you can't observe all of these waves directly. What you see are
individual packets of light that like go here or go there. So there's something fundamentally
probabilistic and quantum mechanical about light. And in that sense, we don't really know like
what light is, though we do have the mathematics to describe it. Well, you could also say that
about everything else in the universe, right? All the math.
particles, all of the force particles, they're all just quantum mechanical wave packets, right?
Yeah, absolutely. We don't know, for example, what a particle is. We have a whole episode talking
about the various philosophical ideas for what it is. That doesn't stop us from having a theory
about it and having mathematics that describe it, even if we don't know who the subject of that
mathematical story is. Right. So if you ask me like, what is light, then boo, boy, that's a whole
big philosophical question. If you ask me like, can you predict what happens?
when light hits a mirror. Oh, yeah, that I can certainly do.
Well, fortunately, this is not a philosophy podcast.
So we'll just focus on the latter part of describing light as waves in the electromagnetic field.
And you're saying that we can, with that description of light, we can tell what happens when it hits different things.
Yeah, that's right. We think about light as a little packet of energy, a little pulse in the electromagnetic field propagating through the universe.
So you imagine like light coming out of the stuff.
star and flying through space and making it through the atmosphere and hitting your skin.
And his first question was like, what happens to that photon?
Is it just like absorbed?
Right.
Well, hopefully he's wearing sunscreen if he's out there in the sun and most of it will get
refracted, reflected, but maybe just step us through the basics.
Like what happens when one of these packets of energy in the electromagnetic field runs
into a matter particle, like an electron or maybe like an atom?
like it are the atoms in his skin. What's going on?
So if you want to think about in terms of an individual particle of light, then you can imagine
like the photon flying through space and it hits the matter. Matter of course is made of other
little particles. And so the photon interacts with that matter. It's not like the photon hits your
skin as a whole big blob. It touches like one particle of your skin. It would like zero in on a
single electron in an atom on the surface of your skin and interact with that electron. And one thing
that it can do, for example, is it can be absorbed by that electron. Electrons can just eat
photons, and then that electron now has the energy of that photon. Yeah, that's pretty well.
Although you said that the photon touches a matter particle in your skin, but that's not actually
true, right? Or at least the idea of things touching each other is kind of controversial or
philosophical. Really, what happens is that they get close enough to each other where they have
some kind of quantum interaction, right? Well, the quantum interaction here is the two
fields coupling directly. Like you have the electron field and the photon field and they overlap in
space and energy passes from one field to another. That's the fundamental way we describe an interaction
is passing of energy from one field to another. If you're talking about two matter particles like
two electrons, yeah, they don't actually touch because they communicate through a photon. So two
electrons don't push against each other directly. They pass photons back and forth. But a photon interacts
directly with an electron.
Its energy flows from the electromagnetic field
into the electron field.
Right, but I guess I meant like
there's no actual touching.
It's just that the one wiggle
gets close enough to the other wiggle
where they somehow, through the magic of the universe,
the energy gets transferred from one field to the other.
I guess that's what touching is, right?
So then now we're in a philosophy podcast again.
But that's an interesting way to think about it
is that it's like energy going from the photon field
to the electron field, right?
Like, that just magically happens.
There's no conduit.
There's no, like, channel for that to happen.
That just automatically happens.
These fields are sort of like kind of on top of each other in that way.
Yeah, as you said, space is filled with these quantum fields.
There's a bunch of them.
There's one for electrons.
There's one for quarks.
There's one for photons.
There's one for every kind of particle.
A lot of those fields ignore each other.
But some of the fields don't.
Some of the fields do talk to each other.
We call that a coupling.
And that coupling is determined by the charges of the particles.
So, for example, the photon field,
can pass energy to any field for a particle that has an electric charge.
That's actually kind of what it means to have an electric charge.
So, yeah, the energy can pass directly from the photon field to the electron field.
Like mathematically, when we describe these fields,
we write them down together in the Lagrangian of the standard model,
and we add a term in front of them, which is not zero,
which means that energy can pass from one field to the other.
So when the photon flies out of the sun and hits your skin,
that energy is propagating through the electromagnetic field
and now into the electron field.
It's absorbed by the electron.
Okay, so that's one thing that can happen to the photon.
It can get absorbed by the electron.
And then after that, a couple of other things can happen, right?
Yeah, it's possible for that electron to then release that energy, like back into the photon field, right?
That's a two-directional interaction.
Electrons can eat photons.
They can also create photons.
They can spit photons out.
That electron, for example, has a bunch of energy now, and the universe doesn't like to have energy density very high.
in one place, it likes to relax,
it likes to roll down to lower potential energy.
So the electron, one thing you can do
is jump back down in energy
and give off a photon again.
And that can happen in lots of different ways.
You can call that reflection.
You can call that fluorescence.
But that's one thing that the bit of matter can do
is it can spit that photon back out
into the universe.
Yeah, I guess there's two interesting things about that.
One is that, first of all,
the original photon is basically gone, right?
like when we think of light
bouncing off of a mirror
or bouncing off of your skin
like actually what's happening
is that the photon dies right
it disappears into that electron
and then a new photon
gets bit out by that electron
you know you keep saying
we're not a philosophy podcast
and then you keep asking philosophy questions
like is the photon killed
when it's absorbed
you know it's really interesting question
is it the same photon well
a photon didn't exist for a moment
it was absorbed into the electron
It's quantum information still exists, right?
It's certainly correlated with the original photon.
So it's not like there's no relationship between the new photon and the old photon.
But yeah, you might say it's a new photon.
It's not the same one.
I guess I mean like in your views of physicists, is that like an actual sequence of events?
Like the photon got absorbed.
The electron realized it had too much energy.
So then it powered down and spit out a new photon.
Like is there a certain amount of time that happens?
in an certain order in which it happens?
It's not an instantaneous process, right?
The electron can absorb the photon and can hold onto it for a little while, and then it
can give it up later.
We had a podcast episode about that process.
It's called fluorescence, and that can be quite delayed, and there certainly can be a time
gap.
On the other hand, sometimes the electron gives it up almost immediately, and it's more like
the photon bounces off of the electron.
For example, in a mirror, what happens is that the photon is basically just immediately
reflected, though it is momentarily held by the electron.
And it's important to consider the other things that can happen.
It's not necessarily the case that the electron gives up that photon.
There are other options.
It can pass that energy to the nucleus of the atom or into the lattice of the material,
basically heating it up.
So there's a few varieties of things that can happen to the electron after it's absorbed
the photon.
All right.
Maybe walk us through a little bit of those options.
So how does it impart energy to the nucleus?
So the electron is interacting with the nucleus in the same way the electron can interact with a photon, right?
It's bound to the nucleus and it's also interacting with other electrons in the material.
And so in the same way that it can like give up a photon, it could also bump up against other electrons or can push up against the nucleus.
All of these, of course, would be mediated by other virtual photons.
But basically, instead of just giving up that photon back out into space, it can create a photon which is absorbed by like the next atom or by another particle.
And that particle can have that energy in terms of like its vibration or its rotation.
There's lots of ways for energy to be stored in matter.
And once the electron has absorbed that photon, it's possible for that photon to get into like many of these different kinds of buckets.
All right.
Well, let's get into some of the examples of what light does as it hits different materials and whether or not it dies or not.
But first, let's take a quick break.
Hello, it's Honey German.
And my podcast,
Grazac's Come Again, is back.
This season, we're going even deeper
into the world of music and entertainment
with raw and honest conversations
with some of your favorite Latin artists and celebrities.
You didn't have to audition?
No, I didn't audition.
I haven't audition in like over 25 years.
Oh, wow.
That's a real G-talk right there.
Oh, yeah.
We've got some of the biggest actors,
musicians, content creators,
and culture shifters sharing their
real stories of failure and success.
You were destined to be a start.
We talk all about what's viral and trending
with a little bit of chisement, a lot of laughs,
and those amazing Vibras you've come to expect.
And of course, we'll explore deeper topics
dealing with identity, struggles,
and all the issues affecting our Latin community.
You feel like you get a little whitewash
because you have to do the code switching?
I won't say whitewash because at the end of the day,
you know what I mean?
Yeah.
But the whole pretending.
and cold, you know, it takes a toll on you.
Listen to the new season of Grasasas Come Again as part of My Cultura Podcast Network
on the IHartRadio app, Apple Podcasts, or wherever you get your podcast.
A foot washed up a shoe with some bones in it.
They had no idea who it was.
Most everything was burned up pretty good from the fire that not a whole lot was salvageable.
These are the coldest of cold cases, but everything is about to change.
Every case that is a cold case that has DNA.
right now in a backlog will be identified in our lifetime.
A small lab in Texas is cracking the code on DNA.
Using new scientific tools, they're finding clues in evidence so tiny you might just miss it.
He never thought he was going to get caught.
And I just looked at my computer screen.
I was just like, ah, gotcha.
On America's Crime Lab, we'll learn about victims and survivors.
And you'll meet the team behind the scenes at Othrum, the Houston Lab that takes on the most hopeless cases.
to finally solve the unsolvable.
Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.
Your entire identity has been fabricated.
Your beloved brother goes missing without a trace.
You discover the depths of your mother's illness, the way it has echoed and reverberated
throughout your life, impacting your very legacy.
Hi, I'm Danny Shapiro.
And these are just a few of the profound and powerful stories
I'll be mining on our 12th season of Family Secrets.
With over 37 million downloads,
we continue to be moved and inspired by our guests
and their courageously told stories.
I can't wait to share 10 powerful new episodes with you,
stories of tangled up identities, concealed truths,
and the way in which family secrets almost always need to be told.
I hope you'll join me and my extraordinary guests for this new season of Family Secrets.
Listen to Family Secrets Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.
I had this, like, overwhelming sensation that I had to call it right then.
And I just hit call.
I said, you know, hey, I'm Jacob Schick.
I'm the CEO of One Tribe Foundation.
And I just wanted to call on and let her know there's a lot of people battling some of the very same things you're battling.
And there is help out there.
The Good Stuff podcast, season two, takes a deep look into One Tribe Foundation,
a non-profit fighting suicide in the veteran community.
September is National Suicide Prevention Month,
so join host Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission.
I was married to a combat army veteran, and he actually took his own life to suicide.
One Tribe saved my life twice.
There's a lot of love that flows through this place, and it's sincere.
Now it's a personal mission.
Don't have to go to any more funerals, you know.
I got blown up on a React mission.
I ended up having amputation below the knee of my right leg and a traumatic brain injury because I landed on my head.
Welcome to Season 2 of The Good Stuff.
Listen to the Good Stuff podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast.
All right, we are answering listener questions today.
And our first one was about light and basically what happens when light hits stuff.
And we talked about how it's actually photons in the electromagnetic field,
hitting the particles in the atoms of the things that you're trying to shed a light on.
And one thing it can do, it can be reflected back,
or the electrons can spit out, basically an identical photon back in the same direction
or sort of the same direction that the initial photon came in at.
But you're saying it could also absorb that photon and give the atom more energy
or the material it hid more energy.
That's kind of what happens when you're sitting out in the sun heating up, right?
Yeah, that energy comes from the sun via photons and gets absorbed by your body.
When you feel hot, that's because the atoms in your body are moving faster.
They're wiggling or sliding around faster.
And that energy comes from the photon.
So yeah, that photon is now like gone.
You know, maybe every time you sit in the sun, you need to have like 10 to the 26 funerals for all the photons that you're killing.
Yeah, it's pretty sad.
You sound really sad.
That's why you should cover yourself in aluminum foil or mirrors or just never go outside
your house.
That's right.
If you want to be a photo vegan.
That's right.
You can join the society for the humane treatment of photons.
But so that's, I guess that's reflection and that's absorption.
What about refraction?
Like he asked like what happens when the light hits like a semi opaque window like in his
camper or, you know, something that's translucent maybe?
What's going on there?
How does refraction work?
So refraction is complicated to understand from this like microphysical picture of a single particle.
And you have to back up and really remember that the path of a photon is determined by the wave equations that are guiding its motion through the electromagnetic field.
Refraction is a very familiar wave phenomena.
When a wave hits another kind of material, part of it reflects, part of it gets transmitted, and then it gets bent in a slightly different direction.
For example, if you have a straw in your glass of water, it looks like the straw is sort of brink.
broken in half because the part of the light that's going through the water gets bent slightly
in a new direction.
So that's what we call refraction.
And that's tricky to understand for like the path of an individual photon, but it's very
straightforward from like the mathematics of the wave equation.
So what's going on then?
Why does light or any wave change direction when it changes the medium it's going in?
So when a wave travels through a medium, it's like wiggling something, right?
And different kinds of medium wiggle in different ways.
So for example, if you shout in the air and then that sound wave hits water, part of it reflects and part of it goes into the water and changes direction.
But it gets fundamentally transformed when it goes into the water.
Right now it's wiggling water molecules instead of wiggling air molecules in order to balance all the frequencies at the surface to make the math add up at the surface.
So everything is like making sense and being continuous.
Those waves sort of have to change direction in order to account for the fact that it's like a new kind of wave.
So that's the fundamental physics of like refraction of waves.
For light, it's a little bit complicated if you want to think about like what happens to one photon when it hits the surface of the water.
How does it know how much to bend?
Right.
And that's determined by the wave equation.
That's why it's fundamentally quantum mechanical.
Two photons hitting a surface might bend in slightly different directions.
But a bunch of photons hitting the surface sort of average out to give you the answer you would expect from the wave equations.
But I guess what like what's happening to the or individual photons?
How does it change direction, for example?
Can't really ask the question what happens to an individual photon unless you're actually observing it unless you're seeing it.
You can only really think about photons as particles when you're observing them.
So you shoot a photon out, it hits the surface of the water, then you detect it somewhere in the water, right?
And you want to know like what happened at the surface of the water.
That's like going to the double slit experiment and asking like which slit did the photon go through.
Really, the photon has many possible paths
between the source of the light
and where you're detecting it.
And quantum mechanically speaking,
it does all of them together, right?
There's not a single story
for what happened to that individual photon.
Right, but I guess it's a little bit different
because to the photon, it didn't change mediums, right?
Like it didn't change how it was,
the electromagnetic field didn't change
between outside the water and inside the water, right?
To a photon, it's just going through the electromagnetic field.
The difference is that it's suddenly surrounded by a bunch of water molecules, right?
And so are you saying like all those water molecules basically act like little double slits?
Yeah, all those water molecules are like little interactions.
How do water molecules change the path of the wave?
Well, remember that the water molecules are charged particles, so they interact with the photon field.
You know, one way to think about it is that like the photon is getting pulled on by all those molecules.
But you can't really have like a single picture of the path of an individual photon and say this one got bent in this particular way.
There's lots of different possibilities for what might happen to the photon when it goes through.
And one photon will go in one direction, another in the other direction.
If you average up over many, many photons, millions of photons, then you'll get these sort of average behavior you expect from a classical wave.
But for an individual particle, it's a little bit random.
Because I guess the photon from its point of view, it's like it's going along, suddenly it sees a wall.
wall of water molecules and some of those molecules bounce it this way or bounce it that way or
right? Is that what you're saying? Mm-hmm. Yeah, exactly. And when you say bouncing, you mean
reflection. Yeah, we mean interaction, which of course means like absorption and re-emission.
And I guess the angle of that reflection will change because the water molecules are, you know,
in random positions. And so you're saying the aggregate effect is that it refracts light along a certain
angle. Exactly. It's the aggregate effect that's controlled by the wave equations. It's maybe
crispest when you think about like reflection. What happens when light hits a mirror, for example?
Sure, it gets absorbed by the atoms in the surface of the mirror, but how do those atoms know
what direction to send the light out, right? Light when it hits a mirror doesn't just come off at any
angle. It comes off at a very precise angle, like it bounces off, right? Following Snell's law.
How do the atoms that absorb the photon know in what direction to send it?
We can't really answer that question from the particle point of view because, you know, they don't really know.
But there's a lot of wave mechanics that are guiding what's happening to the average photon.
Because nobody's actually watching a single particle absorb that photon and re-emmit it.
It's just like an average process for many, many possible paths.
And a lot of those conflict and interfere, giving you overall the photon being emitted in the right direction that's predicted sort of by classical optics.
Right.
Doesn't it all have to do?
you a lot with the crystals, right, and the order of the things that you're shining and light
on, then that's when you get something like a mirror, which bounces things more neatly.
Right.
Mirrors do bounce things more neatly.
It has mostly to do with the conductivity properties of the surface.
Conductors are things that don't allow electric fields very deep in them.
They have a bunch of electrons inside of them, which rearrange themselves to, like, cancel out
any electric field.
And so photons, when they hit something that's like a mirror, don't go very deep.
They bounce right off the surface, whereas things that are not mirrors like your wall, which is white, which reflects a lot of light, doesn't act like a mirror because the photons can get sort of deeper in and interact with things further inside.
And because different photons will get different distances inside, they come out a little bit scrambled.
So images are, for example, scrambled by a white wall, whereas they're not scrambled by a mirror because a mirror reflects everything basically from the very same depth, which is right at the surface.
Right, right.
Oh, that's interesting.
Yeah, but I mean, it also has to do with the surface sector, right?
That's why you can polish things to make them look shiny.
Yeah, exactly.
You want a very flat surface, so all the photons are bouncing off at the same distance.
And that's why conductors, like silver or steel, whatever, make good mirrors.
All right.
Well, I think that answers Matthew's question.
What happens when photons hit stuff?
The answer is they die.
Yeah.
Daniel, I think that's our basic conclusion today.
Yes, every interaction is an absorption and a re-emission,
which means the original photon is gone.
One baby gone.
I mean, we joke about it, but it's kind of true, right?
Like all light interactions, reflection with something shiny, not shining, black, white colors,
you know, all of that is in every interaction, every time light bounces off with something,
it dies, and then it gets resurrected.
I prefer to think of it as like having children because the original photon is influencing the new photons, certainly.
Man, and now you get into whether photons are, how is photons represent?
produce. Is that what you're, I think that's a, gets into a philosophical, biological,
podcast.
Right. We only allow certain kinds of baseless philosophy on this show. That's right. We have
standards here. Only photastic discussions here.
Well, thank you very much, Matthew, for that really intriguing question. All right. Our next
question comes from Tim, and it has to do with stars.
Hey, Daniel and Jorge.
I had a question. Is there such a thing as a star that is so big or so bright that it would actually affect the daytime, nighttime cycles of planets in a nearby solar system? I'm not talking about like a binary solar system. I'm talking about a star that is in a neighboring system. Just listen to your podcast about twinkling stars and that made me thinking about it. Thanks for the answers because I know you'll have them.
well thank you Tim for that question and the faith that you have that we will have answers
I come in every time having the same confidence you do well we'll definitely have something
to say even if we can't answer the question definitively oh that's right that's right
anything technically counts as an answer I learned that with my kids when questions hit the
podcast they die that's right they get absorbed and then we birth them back out into your ear
We emit something.
All right.
Well, Tim's question is that is it possible for a light from a different solar system to affect the feeling of day and night in a planet in another solar system, right?
That's the basic question.
Yeah, basically, can stars change the day, night pattern?
Like, could stars be bright enough that they cause shadows, for example?
I've been out at night looking at the stars and then checking out behind me to see, like, am I casting a star?
star shadow. Oh, star shadow. Sounds like a good gamer tag. But of course, as you look up at the
night sky, those stars are obvious to your eyes, but they're not bright enough to make the night sky
bright, right? To make it feel like it's daytime. Well, technically they do cast a star,
right? Or a shadow star, right? Like, technically, yeah, you are blocking light from stars and
preventing something behind you from getting that light. Yeah. And it's fundamentally the same process
as getting a shadow from our sun.
It's just that our sun is closer, right?
And so it's brighter.
So you notice it much more
because it does dominate the brightness of our planet.
And the thing I love about Tim's question
is that he's wondering about these two different categories,
our sun and the distant stars
and wondering if there's something that bridges them.
Is it possible to have something in between other stars
that are close enough to be sort of like part
of our day-night cycle?
Really cool way to think about it.
I guess maybe the question is like
how close can two solar systems
get so that one sun actually changes the day, night, time feeling of another solar system.
Yeah, maybe Tim's working on a science fiction novel and this is an important part of the
plot.
Right.
Isn't everybody working on a science fiction novel?
I don't know.
I feel like science fiction gets absorbed by the reader and then not always reemitted as a new
novel, right?
Sometimes science fiction novels just die.
I see.
They die in the reader's brain.
Maybe the reader just goes to an excited state of knowledge and enlightenment.
Oh, there you go.
transforms that energy into, you know, their own work.
Their own imagination.
But anyway, here we are not answering Tim's question.
Once again, yes.
But we are trying to hear.
And so I guess the question is how far can two solar systems get before maybe they're not two different solar systems?
I wonder if that's kind of part of the question.
Yeah, because he specifically ruled out like a binary solar system where you have two stars.
It's a really interesting question.
And there's a couple of different parameters we can play with here.
One is where you are in the galaxy, which really determines how far apart stars are, and also how big the stars are, because there's a huge variation in the brightness and the size of stars.
Right.
There are big ones and small ones.
And out in our neighborhood of the galaxy, we're sort of like halfway out from the center of the galaxy.
Things are not very tightly packed.
We're sort of like in the suburbs of the galaxy.
Like the closest star to Earth is about four.
light years away. That's really, really far away. And remember that the brightness of a star
gets dimmer as you get further away. And it gets dimmer by that distance squared. So if you're 10
times further away, a star is 100 times dimmer. If you're a thousand times further away,
then it's a million times dimmer. So that mathematics really works against distant stars.
It's why the sun really dominates our experience. Yeah. And it's why if we were 10 times closer to
the sun, we would feel it's heat a million times more, right? We'd be toast. Yeah, and in our
neighborhood, the stars are pretty diffused. But if you go to the center of the galaxy, things are
much more cozy, right? In the center of the galaxy, it's not uncommon to have stars that are less than
a light year apart or even less than a tenth of a light year apart. And so those stars benefit
from that short distance. They get the same math, but working in their favor to boost their brightness.
You're 10 times closer, now you're a hundred times brighter.
To give you a sense of like what that means, if we had another star as bright as our sun that was like half a light year away, we would see it during the daytime.
It would be like bright enough in our sky to see during the daytime.
Be about as bright as Venus is, which you can see during the daytime.
So like we would look up into the day sky and maybe among the clouds, you would see a little pinpoint of light.
Yeah, you'd see a pinpoint.
It wouldn't change the day-night cycle, right?
You could see it during the day the way you can see the moon, but it doesn't mean that the night would feel like the day.
But it would be something that's visible.
So you could see another sun that was like 0.4 light years away.
You know, if it was even closer, then it would be even brighter.
And in the center of the galaxy, that does happen.
Stars get very close together.
But I guess at one point does it become part of a binary system, you know, like how close can two stars get without them basically being the same, in affecting each other gravitationally?
that they become one big solar system.
Well, stars are always going to pull on each other gravitationally, right?
We are getting pulled on by our neighboring stars, even though they are four light
years away, right?
Our galaxy is getting pulled on by the neighboring galaxy, even though it's millions of light
years away.
So it's just sort of like a cosmic web of gravitational interactions.
And in the center of the galaxy, these stars are all tugging on each other.
But they're not like in stable orbits around each other.
I think for a binary star system, you want them to be like gravitationally cat.
captured by each other.
But it's more like a mosh pit than a bunch of dancing couples in the center of the galaxy.
It's kind of crazy down there.
So I guess if you're close to the center of the galaxy, there's not just probably one star that's half a light year away.
There's a bazillion stars that are lightier way.
So if our solar system was near the center of the galaxy, we would look up at the day sky and it would be filled with pinpoints, right?
Maybe just a huge cloud.
It would all just kind of be super bright everywhere.
Yeah, exactly. And it wouldn't be unreasonable that your night sky might have a very, very bright star in it. You might have a neighbor which is pretty close. And just the same way when you're trying to sleep, if your neighbor has like floodlights on in their house, it can go through your windows and disturb your sleep. Near the center of the galaxy, you might have a neighboring star that's bright enough to disturb your night, especially if that neighboring star is not like the sun if it's one of the big monster stars. Because stars have a huge, very
variation in their brightness.
You know, our sun is pretty bright, but there are many more stars out there that are
much, much brighter than our sun.
Right.
I guess it's all relative, right?
Like what we consider daytime here might be equivalent to nighttime on a planet near
the center of the galaxy, right?
Just from all the life from all the nearby stars, potentially.
Yeah, that's true.
Exactly.
And just to give you a sense of the range, you know, like in our night sky, there are other
stars we can see that are much brighter, like Sirius is a star in our sky.
25 times as bright as the sun.
If you're at the same distance from Sirius as you were from the sun, it would be 25 times as bright.
But that's just like a little step up.
There are other stars, like the biggest stars in our galaxy, one's called Etta Carina,
that are like two million times as bright as the sun.
Two million.
And so any star in the neighborhood of Eta Carina is basically going to be bright all night long.
Yeah.
And I guess it also opens the possibility.
that maybe if you're a planet orbiting a dim star
like maybe like a brown dwarf
or something that's just kind of simmering there
and not really shining as bright as our sun
then for you if you were near the center of the galaxy
then really your sun maybe doesn't even influence
the day and night cycle right
like maybe for you in that solar system
day and night is when your planet
is facing the center of the galaxy
or not facing the center of the galaxy
right like a day could be like
the whole year. Yeah. And the darkest times could be when your son eclipses the other bright
neighbor. So you could have like a star star eclipse. Wow. Yeah. Who said science fiction dies on this
podcast? We're not just absorbing science fiction here. We are emitting it in real time.
That's right. We are creating it. We are redirecting it. We are reflecting these ideas back
at your tape. We want to hear this story. Send us the draft to your novel when you finished it.
Yeah. But make sure we sign an NDA here. I wouldn't trust us.
not to copy your ideas.
Copy.
We're collaborators.
We're co-authors.
We're here workshopping it live, man.
All right.
Well, thank you, Tim, for that awesome question.
I guess the answer is, yes, there could be stars so bright that they do affect the night
date time cycle.
And in fact, if you're close or far away from the center of the galaxy, it might make
an bigger or smaller difference.
Yeah, the whole definition of day and night would be really different.
And it would lead to really complicated patterns of life on that planet, which could be really
fun to explore in Tim's future debut science fiction novel.
Tim Horhe and Daniels' new debut novel, you mean, yes.
Right, yes, of course.
In fact, you'd he go first on the author list?
I don't know.
We'll take that question off the air.
All right, let's get into our last question here about black holes that are maybe made
out of dark matter.
We'll jump right into that hole.
But first, let's take another quick break.
Your entire identity has been fabricated.
Your beloved brother goes missing without a trace.
You discover the depths of your mother's illness
the way it has echoed and reverberated throughout your life,
impacting your very legacy.
Hi, I'm Danny Shapiro.
And these are just a few of the profound and powerful stories
I'll be mining on our 12th season of Family Secrets.
With over 37 million downloads,
We continue to be moved and inspired by our guests and their courageously told stories.
I can't wait to share 10 powerful new episodes with you,
stories of tangled up identities, concealed truths,
and the way in which family secrets almost always need to be told.
I hope you'll join me and my extraordinary guests for this new season of Family Secrets.
Listen to Family Secrets Season 12 on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast.
Hello, it's Honey German, and my podcast,
Grazie Come Again, is back.
This season, we're going even deeper into the world of music and entertainment,
with raw and honest conversations with some of your favorite Latin artists and celebrities.
You didn't have to audition?
No, I didn't audition.
I haven't audition in, like, over 25 years.
Oh, wow.
That's a real G-talk right there.
Oh, yeah.
We've got some of the biggest actors, musicians, content creators, and culture shifters
sharing their real stories of failure and success.
You were destined to be a start.
We talk all about what's viral and trending with a little bit of chisement, a lot of laughs, and those amazing vibras you've come to expect.
And of course, we'll explore deeper topics dealing with identity, struggles, and all the issues affecting our Latin community.
You feel like you get a little whitewash because you have to do the code switching?
I won't say whitewash because at the end of the day, you know, I'm me.
But the whole pretending and code, you know, it takes a toll on you.
to the new season of Grasasas Come Again as part of My Cultura Podcast Network
on the IHartRadio app, Apple Podcast, or wherever you get your podcast.
I had this overwhelming sensation that I had to call it right then.
And I just hit call.
I said, you know, hey, I'm Jacob Schick.
I'm the CEO of One Tribe Foundation.
And I just want to call on and let her know there's a lot of people battling
some of the very same things you're battling.
And there is help out there.
The Good Stuff Podcast Season 2 takes a deep look into One Tribe Foundation,
nonprofit fighting suicide in the veteran community.
September is National Suicide Prevention Month,
so join host Jacob and Ashley Schick
as they bring you to the front lines of One Tribe's mission.
I was married to a combat army veteran,
and he actually took his own life to suicide.
One Tribe saved my life twice.
There's a lot of love that flows through this place,
and it's sincere.
Now it's a personal mission.
I don't have to go to any more funerals, you know.
I got blown up on a React mission.
I ended up having amputation below the knee of my right leg
and a traumatic brain injury,
I landed on my head.
Welcome to Season 2 of the Good Stuff.
Listen to the Good Stuff podcast on the IHeart Radio app,
Apple Podcasts, or wherever you get your podcasts.
A foot washed up a shoe with some bones in it.
They had no idea who it was.
Most everything was burned up pretty good from the fire that not a whole lot was salvageable.
These are the coldest of cold cases, but everything is about to change.
Every case that is a cold case that has DNA.
Right now in the backlog will be ideal.
identified in our lifetime.
A small lab in Texas is cracking the code on DNA.
Using new scientific tools, they're finding clues in evidence so tiny you might just miss it.
He never thought he was going to get caught.
And I just looked at my computer screen.
I was just like, ah, gotcha.
On America's Crime Lab, we'll learn about victims and survivors.
And you'll meet the team behind the scenes at Othrum, the Houston Lab that takes on the most
hopeless cases, to finally solve the unsolvable.
Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.
All right, we are answering listener questions and also stealing their ideas, apparently.
We are interacting with them and we're interacting.
I see.
That's right.
The universe is not a criminal.
It's just very interactive.
That's right.
The podcast host field is interacting with the podcast listener field, right?
There's a coupling.
There's a charge there.
I can feel it.
Yes, I didn't steal any classified documents.
I just interacted with them in my private home.
Let's hope we don't get charged officially.
All right.
Our last question here comes from Matteus, and it's about black holes.
Hello, Daniel and Jorge.
This is Mateus from Poland.
I was wondering about the possibility of having a black hole made entirely from the dark
matter. I understand that it's unlikely to happen because of the dark matter properties,
but I was wondering, how could we detect one? If we can measure the black hole's electric
charge, would a zero charge mean that there is no normal matter inside? How likely would it
be for a black hole to have zero electric charge? This also has led me to some more general
questions. Is the total electric charge in the universe equal to zero? How about on galaxy or planet
level? I'm eager to hear your answers to my questions. Thanks a lot for your great work with
the podcast. All right. Thank you, Matthias, for that great question, and it came to us free of charge.
As all questions do. Now, this is an interesting question. He's asking, well, he's asking several
questions, but the first one was, what would happen if a black hole was made entirely out of
dark matter? He said, you know, he caveats that it's unlike, he knows it's unlikely to happen,
but what if you made a black hole with dark matter? Would it be different? Could you tell the difference
between a regular black hole.
Yeah, and even suggest a way of maybe distinguishing dark matter black holes from normal matter
black holes, which I thought was pretty clever.
He's thinking like a scientist.
He's like, if this were to happen, if I basically speculate about this, can this help me write a grant?
Yeah.
And so there's a bunch of stuff going on here.
First is the idea of what's in a black hole.
What can you make a black hole out of?
And, you know, we think that black holes can eat anything.
They can eat normal matter.
They can eat dark matter.
they can eat other black holes.
They can eat basically anything and grow
because the curvature of space is determined
not just by mass, but by anything with energy.
That's what general relativity tells us.
So black holes can basically eat anything.
You can make them out of normal stuff or dark matter.
But we think that most black holes
are probably dominated by normal matter
because it's harder for dark matter to fall into black holes.
Mostly we think dark matter swirls around in big clouds
doesn't clump together and fall into black holes as often as normal matter.
Right, because it's harder to make a black hole out of dark matter.
I think Mateo's kind of acknowledged that they're harder to make
and therefore less likely to happen in the universe.
But the basic answer is that you can make a black hole out of dark matter.
Like if you can somehow take dark matter, squeeze it down to a small enough radius,
it would form a black hole.
In principle, absolutely, yes, it would.
And the reason that it's harder to squeeze dark matter down,
is that we don't think dark matter feels any other forces other than gravity.
So you can't push on it, for example, to compact it.
It doesn't stick to itself.
And that means it's hard for it to like give up angular momentum.
If it's spinning around a black hole in the accretion disk, for example,
why do things fall into the black hole and not just spin around them forever?
They do that because they lose angular momentum.
They bump into something else in the accretion disk and then head towards the black hole.
Dark matter because it doesn't feel those forces we think just passes right through itself.
doesn't bump into anything, doesn't stick together into big blobs and fall into the black hole.
But it is possible if you somehow got a bunch of dark matter together, it would make a black hole.
Right. And like also given enough time, right? Like if you have a blob of dark matter out in space,
eventually maybe in trimmings of years, it will all collapse into a black hole, right?
That's right, because rotation is acceleration, which means it's giving off gravitational waves.
So even something that feels nothing else but gravity will eventually lose its orbit because it's giving off energy out into the universe and it will fall in.
So yes, eventually dark matter will fall into a black hole.
Right.
Isn't there, I mean, there's a lot of dark matter out there in the universe, a lot more than regular matter.
And the universe is pretty old.
Isn't it possible that at this point some dark matter may have fallen and created a dark matter black hole?
It's almost certainly the case that every black hole contains some dark matter.
While a big cloud is hard to collapse into a black hole, if you have an existing black hole and the dark matter particle just like heads towards it, it's just going to fall in.
There's no like special protection.
So every black hole probably contains some dark matter.
He's asking about like if it's possible to have a black hole that's only dark matter.
Right.
So imagine some big blob of dark matter that's gotten separated from normal matter, which could happen, right?
Like the bullet cluster collision stripped dark matter from the normal matter in those galaxies.
these, you know, these big, vast clouds of dark matter are basically all by themselves,
wait long enough and that would collapse into a black hole.
Right.
He's asking, like, I think you're saying that, you know, most black holes are like milk chocolate,
you know, maybe 30% dark chocolate.
But he's asking, can you have 100% dark chocolate bar?
Can you have a black hole made entirely out of dark matter?
And the answer is yes, right?
That can happen.
The answer is yes, that can happen.
And then we have the question of, like, how could you tell?
Now we run up against a problem, which is that we can't know very much about what's going on inside the black hole.
The No Hair theorem tells us we can know the mass of the black hole, basically how much stuff is in it.
We can know whether it's spinning, and we can know it's electric charge.
And that's the key that Mateos is focusing on to tell us whether or not the black hole is built from dark matter or normal matter.
Because if you take a black hole and you throw electrons into it, you can't tell what happens to those electrons once they pass in,
but it does change the overall electric charge of the black hole, and you can measure that.
The same way you can measure a black hole's mass increasing.
You can measure its charge increasing or decreasing as you add charge to it, because charge is conserved in our universe.
But how do you measure the charge of a black hole if no information can come out?
You can measure the charge of a black hole the same way you measure its mass, right?
You measure the field it creates.
Black holes can make gravitational fields that go past their event horizon.
And in the same way, they can make electric fields that go past their event horizon.
You don't need information to come out of the black hole in order for that electric field to exist outside the black hole.
Now, I guess the question is that Matt Teos was thinking about it was that, you know, dark matter doesn't feel the electromagnetic force.
That's one of the things we know about it.
That's why it's invisible.
You can't see it.
So if you made a black hole out of dark matter, does that mean that the black hole wouldn't feel the electromagnetic force?
Yeah, that's true. If a black hole is made out of dark matter, then it has no charge, and then it wouldn't feel electromagnetism. If an electron flew by a dark matter black hole, it wouldn't feel any force. It's the same way it doesn't feel any force from any other neutral object.
Well, it would feel the force of gravity. It just wouldn't feel the electromagnetic force.
Right. Yes. It wouldn't feel any electromagnetic force. It would only feel the gravity. Just the same way when it flies by any other neutral object, it doesn't feel an electromagnetic force from it.
only its gravity.
All right.
So then I guess Matias was thinking, if that's true, then could we tell whether a black hole
is made out of dark matter or not by measuring its charge?
Like if you see a black hole, you measure its charge, you see that it's zero charged or
that electrons are not affected by, are not attracted or repelled by this black hole.
Would that be evidence that this black hole is made out of dark matter?
Yeah.
And the last wrinkle there is to think about normal matter black holes.
Would they also have zero electric charge?
in which case you couldn't distinguish them from dark matter black holes
or do they typically have some amount of residual charge
in which case an exactly zero charge black hole
would be weird and would be a nice signal of a dark matter black hole.
So that's sort of the last part of the question is how likely is it
for a normal matter black hole to have zero electric charge?
I see.
So if a normal black hole somehow in its formation aid more electrons
than say protons or positrons,
then it would have an overall.
all negative charge, or if it ate, didn't eat enough electrons, it would have a positive charge.
You're saying maybe a zero charge, black hole wouldn't tell us that it's made out of dark matter
because it can also happen normally in a black hole.
It can also happen normally, and it's a bit of a probability thing.
Black holes are just randomly eating particles.
What's the chances that it's exactly balanced, that it eats exactly as many positive particles
as negative particles?
On one hand, it's very unlikely to get exactly that balance.
On the other hand, it's also the most likely outcome in the same way that, like, if you flip a coin a million times, what are the chances you're going to get exactly 50% heads and exactly 50% tails?
Well, it's unlikely to get exactly that number.
It's also the most likely outcome, right?
Right.
And also, I guess it would be kind of hard to make a pure dark matter black hole, right?
Like if you have a pure dark matter black hole and one electron falls into it, then suddenly it's got a charge.
Yeah.
So that would make this pretty challenging.
But it is really interesting to think about what is the charge distribution of black holes out there in the universe?
Are they all basically zero or very close to zero?
What is the overall charge of these things?
We have a whole episode planned about the charge of the entire universe and the galaxy.
But briefly, most of the stuff that's out there is close to neutral because the electromagnetic force is so strong.
that anything that isn't neutralized, the force basically cancels it out.
It'll like suck electrons off of something to balance it out, mostly.
Like the sun, for example, actually has a slight charge because its solar wind has electrons
and protons, but it's easier for the electrons to escape the sun than protons because they have
a lower mass.
So the sun gives off more electrons than protons, so it has a very slight positive charge.
Interesting.
I do agree the sun is a very positive.
influence on my life, at least, for sure. I mean, it's not free of charge, but I do have to
wear a sunblock. So to answer Mateus's a question, it's a really clever way to think about what
might be inside a black hole, but I think it would be very challenging to prove that a black hole
is a hundred percent dark matter, because it's possible to get zero overall charge even without
dark matter. Right. And also, I guess it maybe points to this idea that black holes are black holes,
right? Like, even if it's dark matter that falls into it, dark matter eventually just get
gets transformed into pure energy, right?
So like a black hole really kind of grinds everything up and maybe makes it impossible to tell
if what you put in was dark matter or not.
Yeah, we don't know the quantum states of the things inside the black hole.
It's one of the deepest questions in modern physics.
Like what is the form of matter inside there?
We don't know the answer because we don't have a theory of quantum gravity.
We don't understand how gravity works for individual particles.
So once the dark matter is inside the black hole, it's not really dark matter anymore.
It's something weird and new that we don't understand.
Interesting.
All right.
Well, thank you, Mateos, for that question.
These were all pretty good questions.
Not really light.
They're pretty heavy in content.
Last one's super extra heavy.
So for those of you on an intellectual diet,
sorry for the heavy meal.
Hopefully, it expanded your brain, not your waistline.
But thank you for emitting these questions,
these particles of curiosity that we love to absorb
and to shoot back at you.
Yeah, we hope we shed some light on these topics, and that you come back for more.
Thanks for joining us.
See you next time.
Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of IHeartRadio.
For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.
It's important that we just reassure people that they're not alone, and there is help out there.
The Good Stuff podcast, season two, takes a deep look into One Tribe Foundation, a nonprofit fighting suicide in the veteran community.
September is National Suicide Prevention Month, so join host Jacob and Ashley Schick as they bring you to the front lines of One Tribe's mission.
One Tribe, save my life.
twice. Welcome to season two of the Good Stuff. Listen to the Good Stuff podcast on the Iheart
radio app, Apple Podcasts, or wherever you get your podcast. Every case that is a cold case that has
DNA right now in a backlog will be identified in our lifetime. On the new podcast, America's
Crime Lab, every case has a story to tell and the DNA holds the truth. He never thought he was going
to get caught and I just looked at my computer screen. I was just like, ah, gotcha. This technology
already solving so many cases.
Listen to America's Crime Lab on the IHeart Radio app, Apple Podcasts, or wherever you get your
podcasts.
Let's start with a quick puzzle.
The answer is Ken Jennings' appearance on The Puzzler with A.J. Jacobs.
The question is, what is the most entertaining listening experience in podcast land?
Jeopardy-truthers believe in...
I guess they would be Kenspiracy theorists.
That's right.
To give you the answers and you still blew it.
The Puzzler.
Listen on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.
This is an IHeart podcast.
