January 26, 2021 • 41 mins
Daniel and Jorge talk about what kind of elements are inside a black hole, how to respond to aliens and whether physicists are useful or useless in a zombie apocalypse.
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Speaker 1 (00:08):
Hey, Daniel, congratulations you're making it to the year. Thanks.
It was a bid harrowing. Wasn't sure we were going
to get here. Our physics is preparing for what might
throw at us. Man, I'm hoping we don't have to.
If we get to the point where we need physics
to save us, it's probably not a small problem. I
guess CERN can't help with the plumbing issues there. You know,
(00:31):
if you want a black hole flush down your pipes,
give us a call. I think we'll save our call
Discern for the big st of you know, like asteroids
and zombie apocalypse. Oh my goshe will probably be the
year of the asteroid zombie apocalypse. That's a new show.
It's called The Orbiting Dead. I am jorheam and cartoonists
(01:06):
and the creator of PhD comics. Hey, I'm Daniel. I'm
a particle physicist and I love all science fiction, except
for zombie apocalypse movies. M That doesn't count as science
fiction to you. No, it counts as science fiction. I'm
just not that into it because you don't like it
or it makes you afraid. I'm not that afraid of zombies,
(01:27):
you know, in real life. But it's just kind of boring.
They're they're always just getting chased by these slowly shuffling
zombies and it's always just like, you know, how many
heads can you explode before they kill you? Oh? Man,
you've been watching the wrong zombie movies. But you know
they run and they climb walls. Now they've upgraded, all right,
I'll look for zombies to point o. Welcome to our podcast,
Daniel and Jorge Explain the Universe, a production of My
(01:49):
Heart Radio in which we tackled the biggest questions of
the universe. We toss our minds into the depths of
space and try to understand where everything is made and
how everything works. We zoom into the littlest particles and
try to wrap our minds around what they're doing and why.
Our goal on this podcast is to literally explain the
entire universe to you, because there is a lot of
(02:11):
a universe to explore, and there are a lot of
mysteries out there, a lot that we don't know about
the universe, about what it's made out of, what's out there,
what can happen, and what is possible in these vast
cosmos we live in. That's right, It turns out even
two hundred and fifty episodes of this podcast is not
enough to explain the entire universe. It's a big place
with a lot of mysteries, and we love talking to
(02:33):
you about it, and we love hearing from you what
you'd like us to break down. Yeah, even after two
d and fifty episodes, people still send us questions. We
get questions through social media, emails to people. Ever to
choke up at your door, Daniel with questions You know
you joke, But when we had classes in person, I
used to hold office hours in person and occasionally a
random person from the street would show up and said
(02:54):
they looked me up and came in with a question
about the universe. So yeah, kind of wow. Is there
a zooming ovalent now? For that, you know, there is
this equivalent. I have monthly public office hours so people
can drop in and ask physics questions. Wow. Cool, All right, Well,
today we are actually addressing listener questions. We are taking
in questions and trying to break them down in fifty minutes.
(03:17):
Because we know that while we do our best to
talk about the mysteries of the universe in a way
that makes sense to you, there's always some angle we
didn't consider something that makes you wonder something that doesn't
make sense to you. So when that happens right to us,
let us know what you're still wondering about, and we'll
break it down for you, either over email or on
the podcast. So on the podcast today we'll be tackling
(03:43):
listener questions Number four teens. Teens are fourteen episode. Yes
we are officially teenagers. I think we were teenagers one
episode ago technically. But yeah, that's a lot of questions
we've answered. Each time we answered like three, so you know,
you would think out the two and fifty episodes, we
would have answered everyone's parties about the universe. Do you
think so? But they keep coming in. So today we
(04:04):
have three awesome questions about black holes, about our favorite topic, aliens,
and our least favorite topic, zombies. That's right, So thank
you to everybody who's sent in questions. And if you
have a question, please don't be shy. Yeah, we love
to get your questions and Daniel loves to answer them.
Will usually answer them, right, I mean you'll usually answer, Oh,
(04:26):
I answer every question. You engage with us on Twitter
or send us an email, you will get a reply.
I guarantee it, but if they don't get a reply,
that means we might be doing it on the show. Right. No, actually,
I right back to everyone. Sometimes people also get a
special podcast episode if I think the question is exciting
enough that everybody might want to hear the answer, Like
if there's zombies, then I would think you want to
(04:48):
stay away from that question. But maybe maybe physics will
save us from zombie. We'll see, all right. Well, the
first question is about black holes, and it comes to
us from Patrick from Nashville, Tennessee, Daniel, and Jorge. My
name is Patrick oh Leary from Nashville, Tennessee. I have
a question for you guys. I was curious what would
the chemical or elemental makeup of a black hole consists of.
(05:09):
If our son is made of hydrogen elements fusing into helium,
and if other life stages of stars include heavier elements
fusing and so forth leading up to this big collapse,
wouldn't it seem reasonable that a black hole will consist
of some super heavy element resulting from some sort of
hyperfusion occurring during and after the gravitational collapse. Would there
(05:33):
be an element that doesn't fit on the periodic table?
That may have some sort of infinite density. Would it
even be an element or would this singularity potentially be
something entirely different? Is there something else that this matter
in the black hole could theoretically be. I just want
to see what y'all thoughts are. We really enjoy the
show and uh look forward to hearing your answer. Thanks. Well,
(05:56):
that's a super heavy question from Patrick. Yeah, it's an
awesome question thinking about weird places in the universe that
can make weird kinds of matter. So super awesome question,
thanks Patrick. Yeah, I guess the fundamental question is what
is a black hole made out of? We know it's black.
It's I mean, it's made out of like charcoal. It's
(06:19):
just an aluminum sphere with black paint on it. I mean,
sorry to break everybody's bubble here, but that's all it is.
It's fake news exactly. It's fake physics news. Huh. I
can see his reason in there. It's pretty interesting and
pretty convincing. Like if you think about heavy objects in
our universe, like stars there made out of hydrogen and
(06:40):
things are fusing inside and gravity is crushing them down
and they get older and explode and come back together.
They're making heavier and heavier elements, and so does that
mean that when you get to the ultimate dense object,
does that mean it's made out of super heavy elements. Yeah,
this is a super fun question. I thought it'd be
fun first to think about, like what is the mass
(07:01):
of the stuff that turns into the black hole, like
just before it becomes a black hole? What mix of
stuff do you have there? And then we can talk
about what happens to it as the black holes collapsing,
Like does it form some new weird state of matter?
Could you even call that an element? Etcetera, etcetera. Oh,
I see, like the scene of a murder. Let's go
let's go back to right before the actual event and
(07:23):
see what conditions are there, and then maybe that would
tell us what happens when the actual black hole forms. Yeah, exactly.
We're not murdering any iron here. I think of it
more like cooking, you know, And we want to make
sure we understand what are the ingredients we're just killing irony,
We learned straight to the answer that's right, or we're
cooking it up one of the two. All right, Well,
he mentioned stars because a lot of black holes come
(07:45):
from stars, right, and stars collapsing or super annobody. Yeah,
and so there's two categories of black holes. They're the
super massive ones at the centers of galaxies. But let's
focus on the other ones, the smaller ones that are
stellar black holes. And this happens when you have a
star and it gets too heavy and the gravity sucks
it in and eventually becomes a black hole. And he's
totally right that this is where heavy elements are made.
(08:07):
I mean, the universe started with mostly hydrogen, and the
way you get heavier elements is that you fuse hydrogen
nuclear together to get helium, and then helium together to
get heavier stuff, and you work your way up the
periodic table, eventually getting to iron. And so in the
center of stars are these conditions to take two elements
and turn them into a new element. Right, the amazing
(08:28):
thing that we once thought it was impossible, alchemy actually
happens all the time at the centers of stars, creating
new kinds of matter. So that happens in our universe.
That's pretty awesome, Yeah, because the elements are just different
combinations of the same three things, right, quarks and electrons,
and so you know, if you if you get something
that has three quarks and two electrons, and you compress
(08:50):
it with something that has four quarks and another three electrons,
and you get something that's additive. Right, yeah, exactly, You
just add them together and to make a new element, though,
what you need to do is to add a new
proton to the nucleus, Like a typical atom has protons
and neutrons, which of course are made of quarks in
the nucleus and then surrounded by electrons. To get to
a new element, like to go from helium to lithium
(09:12):
or something, you need to add protons, change the charge
of the nucleus, and then add more electrons to make
it neutral. The other thing you can do is add neutrons. Right,
If you add neutrons, that doesn't change the element, just
changes the isotope. Right. You've heard of like uranium two
thirty eight or uranium two thirty five. That tells you
how many nucleons are in the nucleus. They're both uranium
because they have the same number of protons, but they
(09:34):
have a different number of neutrons, right, And so that's
what's happening inside of stars, is that you're making these
heavier and heavier elements, but only up to a certain point, right,
Like you can build it up through carbon and silicon,
but then you get to iron. Yeah, exactly, if you
want to make super heavy elements, you can keep doing
that fusion process, but only up to iron. Up to iron,
(09:55):
it releases heat, and so it drives the reaction and
makes it happen more and more. Above of iron, it
absorbs heat. So you confuse to iron nuclei together to
make something heavy, but it costs you heat, and so
it cools down the star. And that's why stars that
build up too much iron inside them collapse and form supernovas,
because it's the pressure from that heat that keeps the
star from collapsing. So if the fusion actually causes the
(10:18):
star to cool down, then it's actually encouraging it to collapse.
It's working in the same direction as gravity, rather than
pushing out against it. And so that's why stars collapse
after they get it big enough iron core, right, And
when these stars collapse, that's when you get the heavier elements,
right because of the explosion or what Well, actually, that's
something we've only recently understood. For a long time, people
(10:39):
thought that you've got the heavier elements gold and platinum
in that collapse or in the supernova that happened just afterwards,
because they thought maybe the conditions were crazy hot enough
in the supernova to force extra neutrons onto an iron
and then those neutrons would decay into protons and you
end up with a heavier element. But it turns out
that's not the case. That most of the gold and
(11:01):
the platinum and the heavy stuff in the universe is
not actually made in supernovas. Yeah, and they learned this
because they found bits of supernova in the ocean. What crabs,
What does a bit of supernova look like? Yeah, Well,
on the outer layers of the supernova are these little
seeds like heavy elements, which then get covered and stuff
(11:21):
from the supernova and blown out into space. And these
are special little grains which you can later identify. And
like our Solar system is made up literally of star dust, right, well,
some of that star dust are these little grains from
supernova and you can find them and you can study them,
and they've looked at them and they've tried to understand
whether they have evidence in those grains for the formation
(11:42):
of heavy elements. Is like particular signal you need that
shows you that heavier elements were made during the supernova expansion,
and they don't see them. Right, you need this marker.
It's plutonium two forty four, and they just don't see
them in these grains that they find buried in the
ocean crust. But now we have another candidate for how
we those super heavy elements were made. What's a candidate? Well,
(12:03):
instead of being created during the supernova, we think that
sometimes these stellar collapses lead to neutron stars, these very
very dense objects. They're not heavy enough to collapse all
the way to a black hole, but are heavy enough
to be this crazy new form of matter just neutrons.
And sometimes those neutron stars can collide, they can find
each other in a binary system, and they can spiral
(12:24):
in and form this collision and those of the conditions
you need to make gold or platinum or these super
heavy elements. What that's wild? Wait, so I know neutron
star is just like a giant mass of neutrons. Right,
you don't even have elements or atoms. It's just all neutrons.
It's just all neutrons. It's like some new element that's
pure neutrons and new protons. It's a weird form of
(12:45):
matter that frankly, we don't understand very well. And so
you're saying, and sometimes two of those collide, like crashing
to each other, and then when in the crash they
create elements, or when they break apart, they create new elements.
In the crash, they create those months, and the fact
that there's a collision sprays those elements out into the universe,
which is why now we find those elements on Earth.
(13:08):
For example, most of the gold and the platinum on
Earth we think is produced in the collisions of neutron
stars billions of years ago. Wow, that's a weird sentence.
Neutral collision, like a collision that doesn't care. It's amazing
because it means that formation of gold and platinum is
(13:28):
much more rare than we thought. Neutron stars don't collide
as often as you have supernova, but when you do
have a neutron star collision, you make a lot more
of these heavy elements than you would in a supernova. So,
for example, we used to think that supernova collapse is
produced about one moon's worth of gold. That's a pretty
big chunk of gold. And we think like the universe
(13:49):
was sprinkled with all these basically moons of gold. But
now we think that it happens more rarely. But when
it happens, when you get these neutron star collisions, you
get like a Jupiter of gold. Whoa, that's a lot
of blink And so it's more like the universe is
sprinkled with these really big chunks of gold rather than
more like evenly distributed with little, you know, sprinkles of gold.
(14:10):
It's like chocolate chip cookies rather than chocolate sprinkles. All right,
so let's get made back contract of the black hole.
So that's how we get heavier elements in maybe nutron
stark collisions. But then do those neutron stars become black
holes or not? No, they usually just get torn apart.
Sometimes if they get over the threshold, they can turn
into black holes, but not all the time. Most of
(14:31):
the black holes that are out there, these stellar mass
black holes, start out as sort of larger suns like
ten to fifteen stellar masses, which then threw a lot
of fusion, builds up a heavy iron core, and collapse
straight to a black hole. And so they're potentially you
can imagine heavier stuff being made or weird forms of
matter being made in a supernova in the supernova which
(14:53):
leads to the collapse into a black hole. Yeah, oh,
I see. So there are heavy elements due to neutron
stark collisions. But when you get a black hole from
a collapsing star, you may also make heavy elements. You might.
I mean, it's not something we understand very well. And
you know, let's think about the ingredients you have there. Say,
for example, you start with like ten solar masses of stuff.
(15:15):
You have a big sun which makes a heavy iron nucleus,
and then it collapses. You might be imagined that you
start with ten solar masses of iron, but it collapses
before it turns the entire mass to iron. So you
probably have like a heavy core there that's like one
or two solar masses worth of iron that forms the
sort of gravitational center that leads to the black hole.
(15:36):
So you've got a lot of iron there, and then
you've got a lot of other in rushing matter during
the collapse exactly, And those are the conditions you need
to make new kinds of matter. Right, you have iron,
which is very heavy, and then you have a lot
of protons and neutrons coming in. But it's a very
strange situation. I mean, it's like much denser and much
hotter than even neutron stars. So I think that's the
(15:57):
guide you might be imagining. You have iron, and you
have all these other particles, and you're adding them together,
you might be making heavier elements instead. Typically what you
make are not elements like what we recognize, but weird
new forms of matter like you see in neutron stars, right,
because you need to get to the right density to
create the black hole, right, So at some point you
(16:17):
do need to sort of create this weird kind of
super heavy mass. Yeah, exactly. Formation of new elements requires
that you take a nucleus, you add protons to it,
and then you sort of like let it go off
by itself and be stable. Here we're taking the results
and we're squeezing it down really intensely, So all the
protons are just going to turn into neutrons because they're
gonna get an electron squeezed into them, and then most likely,
(16:38):
instead of forming weird new elements, you're gonna get really
strange neutron rich matter, you know, strange new kinds of matter.
We haven't even imagined weirder things than neutron stars. Right.
Maybe the answer then is that in a black hole,
or at least as you're getting into a black hole,
like regular elements can exist, Like you can't have an
element where it's like neutrons and pro autons and electrons.
(17:01):
It's like it's the conditions are so extreme. Everything is
compressed into this weird new type of matter. Yeah, exactly,
and the distinction between like this atom and that atom
breaks down when the atoms get so close together and
get so pushed on each other. What you're really going
to get is some sort of like weird fluid of
neutrons and protons and electrons, and that's going to get
compressed into something even weirder, and you might get, for example,
(17:23):
like a quark gluon plasma where the quarks are no
longer bound even into neutrons and protons because they're so
dense and intensely pressured. So basically you're like recreating the
conditions of the early universe sort of in reverse. Wow.
All right, well that's just leading up to the creation
of the black hole. Let's get into what might be
inside of it once the black hole is made. But first,
(17:44):
let's take a quick break. All right, we're answering listener
quite Shans, and our first question was about what element
is a black hole made out of? Like is it
(18:05):
some kind of new kind of super heavy element. And
it seems like, at least going into the black hole,
we don't have actual elements. By the time you're you're
dense enough to create a black hole, you're in this
weird state of matter. Yeah, because elements are not fundamental, right,
They're not like a basic thing in the universe. There's
sort of like a special configuration of quirks and electrons
that require certain conditions, you know, certain temperatures, certain densities,
(18:28):
and if you get hot enough and you get dense enough,
then you just don't have elements anymore. So it doesn't
really make sense to talk about like is this plutonium,
is this uranium, is this black holium? It's some new,
other weird kind of matter black holium like that it
sounds holy. All right, Well that's before you go into
the black hole. So like at the core and like
the time of birth, the black hole is probably at
(18:50):
the core made out of this weird super heavy neutron soup.
But what about like after it forms like boom, suddenly
I have a black hole and you know, stuff keeps
falling into it. What can we say then about what
it's made up? Like if it grows, then it's probably
not mostly this neutron soup. That's right. We're talking about
the super dense conditions that are going to be like
at the very core of the black hole. What's sort
(19:12):
of like on the outskirts of the black hole, just
inside the event horizon, for example, but not super close
to the very dense material at the center that's maybe
forming a singularity. Well, we think that inside a black
hole space mostly works the same way as it does
outside the black hole, except that it's sort of like
oriented towards the center. So, for example, if you toss
(19:33):
a banana into a really big black hole one where
the spaghettification doesn't happen until you get close enough to
the center, it'll just pass over the event horizon and
continue drifting in towards the singularity. From its point of view,
there's nothing special there at the boundary, it'll still be
a banana. But for how long? First of all, they
nat gets spaghettified, and does that sped getification also kind
(19:56):
of get rid of elements. Does it? Is it a soup?
Is it a bananas By the time it goes in,
It's definitely a banana smoothie by the time it goes in.
When you take a banana, you make it into spaghetti
and then you put that spaghetti in the blender and
you get a smoothie banana spaghetti. That's probably very popular
in Italy. What kind of sauce or wait, can you
(20:17):
put parmesan cheese on banana spaghetti? It's gluten freedom. As
you approach the center of the black hole, that obviously
the tidal forces are going to be very, very strong.
That's the difference in the gravitational force between one side
of the banana and the other side of the banana.
That's what's responsible for the spaghettification. It's going to pull
it apart, and then as it gets closer and closer,
(20:38):
those tidal forces get stronger and stronger, pulling those little
bits of the banana apart further and further, and eventually
it's got to hit some really dense part of the
black hole, someplace where the matter is really dense, and
then it'll just you know, join whatever that is, whatever
that is Is that an official element in the in
your physics table. That's the official way of us saying,
(20:58):
we really just have no idea what's going on at
the center of the black hole. So yeah, whatever that is.
So then that's kind of the real answer, because all
these things that we think are might be happening beyond
even horizon, we don't really know right for sure, We
don't really know for sure. And the sort of two
directions in which we don't know, Like we don't know
from a sort of nuclear physics theory perspective, what happens
(21:20):
if you squeeze neutrons together even harder than the conditions
of a neutron star, Like we can't do those calculations
right now for a neutron star, Like we can't sit
down on a computer and simulate a neutron star because
the calculations are too difficult. So even heavier than that,
even crazier conditions that we also cannot do. Also from
a sort of like black hole theory point of view,
(21:41):
we just don't know what the distribution of matter is
inside the black hole. General relativity says there's a singularity
of infinite density, but we know that doesn't really make sense,
and the quantum mechanics says it's impossible. So there's a
lot of questions about what's going on at the heart
of the black hole, not just like what is the
matter made out of? Once you get there? All right, Well,
it sounds like the answer for Patrick is that a
(22:04):
black hole is made out of We have no idea
exactly or black holio. It's kind of a mystery, but
we know that when you make a black hole, it's
not like an element. There aren't any elements inside. It's
more like this kind of hot mess of a soup
of neutrons. Probably probably exactly. All right, let's jump into
(22:26):
our next question, which is about aliens from space. So
we have a question from Ignacio, and he's from Jupiter.
Is that Jupiter Florida? Uh No, I'm not sure if
he's talking about Jupiter Florida or Jupiter the Solar System.
He might actually be an alien, in which case, why
is he asking us? All right, everybody, get ready to
listen to the first message from alien. His name is Ignacio.
(22:51):
There is this question, Hi from Jupiter. Apparently my question
is that, well, we are always wondering it would be
to receive my search from an advanced aliens realization. But
if we were to discore in disputable evidence of an
abilience relization existing different way planet that is roughly equal
(23:12):
to us in technology, how could we send them a message?
How will we make ourselves known to them? All Right,
that's a pretty cool question. The question is if we
ever find evidence of aliens, like if we get a
signal from far away or like we figure out the
aliens out there, how can we ever reach them or
a column or or text them or send them at
(23:35):
d M. Yeah, that's a really fun question. I mean
I always like to think about what would be like
to get that message, But then it's really interesting to wonder,
like how could we respond with technology is available to us?
And what should we say? Yeah, like, I guess if
you find that they're aliens, like you know, the next
star over like four light years away or thirty light
years away, Like, do we have technology that can beam
(23:58):
a message that far know? We do, or at least
until very recently we did. We probably heard of the
Arecibo radio telescope. That antenna can receive messages, but it
can also send messages out into space. It's a giant
like dish wouldn't we want something more I guess focused
or can that do? Like a focused beam of message? Well,
(24:19):
the dish allows you to basically capture a bunch of
the messages put out by the antenna and focus it
all in the same direction. That's the idea behind a
parabolic dish is that it bounces off the message from
the antenna all in a parallel direction, so allows you
to create a directional beam. And a directional beam would
be very very important. Otherwise the power of your message
(24:39):
would fall really really quickly as it got further and
further from Earth, right like if you transmitted like in
a broadcast antenna, it would just kind of spread out
in all directions and by the time it gets to
you know, thirty light years away, they probably couldn't hear it. Yeah, exactly,
just like a candle in the dark. It's very bright
close up, but it falls off like one over distance squared,
(25:00):
and so twice as far away it's one fourth the intensity,
and a hundred times away it's one ten thousands the intensity.
And so I've actually done this calculation to figure out
how far away could an alien planet be for us
to hear a message using Arecibo, and it turns out
that if they have an air cebo sized telescope and
they're broadcasting in every direction, we would have to be
(25:21):
within a one light year of their planet to hear
it with our air cbo telescope. That's not good enough,
because we're we're further away from that. That's right. There
are zero stars within one light year of Earth. So
basically for us to get a message from another solar system,
they would either have to broadcast it in all directions,
much more powerfully than our technology could, much more powerfully
(25:42):
than air cbo could broadcast, or they would have to
beam it at us directly, which means they would have
to know we're here and send it to us intentionally.
Now can you do that? Can you stand out an
electromagnetic signal in a focus way, kind of like a laser? Sure, exactly,
you could use a laser for example. I mean, radio
waves are just a kind of light. A laser also
(26:04):
sends out a beam of light, So it's just a
question of like what frequency do you want to use?
The best way to communicate through the universe is to
choose a frequency that's not easily scattered or distracted or
absorbed by other stuff, and so things in the radio
spectrum are actually a great way to communicate. Is there
such a thing as a radio laser? Can you shoot
like a radio beam? Actually? Yeah, there are people working
(26:26):
on building semiconductors capable of generating radio frequency laser beams,
so that would be super cool. That's one way to
communicate with aliens is to send them a message basically
using electromagnetic radiation, which means, you know, light or ultraviolet
or infrared or radio somewhere on the spectrum, pick something
(26:47):
that is sort of quiet in the universe. But you know,
if we get a message from aliens, then we should
respond basically in the same way that they wrote to us. Right.
If you get an email, you don't then send somebody
a text? Why not? That's totally inappropriate. Man, If you
get a text right back with text, you get a
phone call, you don't write somebody a letter in response, right,
(27:08):
So if somebody sends us a message via e M waves,
you know, radio message, then we should respond in the
same frequency. Right. But I guess the problem might be
that maybe we got it in one way, but we
don't have anything powerful enough to send it the same way. Back. Yeah, well,
I guess that would make a pretty good case for funding, right, Like, hey, look,
we got this message, although you know, I'm not sure
(27:29):
it's such a great idea to respond to aliens. You know,
we don't know these folks at all. It's like, do
you pick up the phone when you get a number
you don't recognize? Not all the time. That depends how
bored ant anyway, and how lonely I am, and depending.
I mean, imagine that we're out there in the universe
and we've just become technologically savvy enough to get these messages.
(27:49):
We're probably the youngest civilization out there because we've just
burst on the scene, and so we'd be a pretty
easy mark, you know. Alright, well, so be mean with
some sort of radio laser would be our main options.
We have any other options to send the message out Well, basically,
it's just all kinds of radiation, and the kinds of
radiation that can transmit through space are either photons or
(28:10):
other kinds of particles. So we could imagine, for example,
shooting a beam of particles at an alien star and
use that as a way to send messages, you know,
like Morse code via neutrinos for example. M I wonder
if the problem would be, like, if we shoot a
laser at an alien civilization, would they interpret that as
a as an act of war or something? You know
(28:32):
what if they don't get the message, what if it
just goes over their head and they're like, they're shooting
at us. Well, I would encourage us to not use,
for example, Morse code in nuclear explosions. But I think
that a laser beam would not be interpreted as an
active warming. By the time I guess to them, it's
going to be so faint they would have even trouble
picking it up. So if they interpret that as an
act of war, then they were just looking to start something.
(28:54):
I see they're happy, in which case maybe we shouldn't
be something exactly exactly all right, So it sounds like
the answer is we have the technology to write to
any aliens folziation, and we've done it. In fact, in
the seventies, there was a really weird message that we
saw come from space. It's called the Wow signal because
nobody understood it. And at the time that we saw
(29:14):
this message come in, some astronomer wrote wow on the
transcript of it as it printed out from the like
old school printer, and we got this and it came
from space, and we don't understand it. We don't know
was it Aliens, was it just some weird new kind
of star. Nobody's ever understood it because it's never been repeated.
It was just a one time event. But we drafted
a response and sent it out back in the direction
(29:36):
of the signal, hoping maybe someday somebody would read it.
What do we say in this message? Up, we said,
new phone. Who did know? What we did is we
communicated something about where we live and how our life works.
We showed them our number system, We described the basics
of our chemistry. There's a little illustration of the shape
(29:58):
of the human body, and and then the sort of
directions to the solar system. Well everything a alien species
would need to come and conquer us, basically all of
our passwords, our biggest weaknesses save words exactly, our elementary
school teacher, all that stuff. Yeah, it was sort of
a naive message, but it's sort of like hopeful, you know,
(30:21):
we hope that somebody reading it would understand it. And
in this spirit of exploration of the universe and physics
and whatever, come and send us a message back and
tell us something about their civilization. All right, so we
sent out using the RCIBOW antenna, and do we think
it made it or do you think it's too weak?
By the time it gets there, it might be too weak.
(30:41):
But we don't know what their technology is. But it
won't get there for quite a while. We don't know
who's out there and maybe receiving that message. But the
message came from something called M thirteen, a globular cluster
that's about twenty five thousand light years away, so it's
going to take a while before it gets there if
that's where their original message came from. All right, it
sounds like we have options for sending messages neutrinos or
(31:04):
radio telescope or maybe these radio lasers. But you were
telling me there is one way right now, if you
want to broadcast a message out into space, there is
a way to do it. It turns out that if
you use Craigslist, there's an option on Craigslist to broadcast
your message out into the Solar System. No what, seriously,
the CEO of Craigslist, this guy, Jim Buckmaster, bought a
(31:25):
bunch of time on the deep space communication network this
place in Florida that can broadcast into space. So they're
picking ten thousand ads to broadcast into space. So if
you're having a garage sale and you think, you know,
maybe Ignacio from Jupiter should come by and check out
what you're selling, then hey, click the button and Craigslist
will advertise in space. Wow, that's crazy. So not only
(31:50):
are we inviting people to to come attack us, reminding
them to come rate our garages. Like, I don't want
my junk to just reappear somewhere else in the neighborhood.
I want it off planet. Well, we do have a
lot of junk, and it would be good if evan
alien came and took away all of our our unused
and outdated toys. Hey, one species junk is another species gold, right,
(32:11):
so yeah, maybe they love all televisions and satellites. All right, well,
thank you Ignacio from Jupiter for that question. And now
let's get into our last question about zombies. But first
let's take a quick break. All right, we're answering listener questions,
(32:40):
and our last question here is it's sort of debatable
whether it's a physics question at all. Maybe I don't
know you have a question from Lucas from Finland. Hello,
Daniel and Harney, Greetings from Finland. This is Lucas. Have
a question, Um, which would you more likely survive using
physics and nuclear winter or a zombie be apocalypse? Wow? Yeah,
(33:02):
I guess the question is in an apocalypse, what are
physicists useful for besides food? Maybe? Like if you had
a physicist in your little, you know, survival group, are
they an acid or are they allowed a liability? When
you say food, you mean to cook the food right
as a chef, right, not as a source of sustenance.
(33:22):
That's what I'm assuming you're talking about here, you know,
and the apocalypse. You know, you gotta You're gotta be
flexible when you're thinking. You really learned who's your friend
when the apocalypse comes? And who's your dinner? I really
learned from shows like The Walking Bead. Maybe I should
watch some of those shows. You want to be prepared.
This is a fun question because I often put questions
(33:44):
on the podcast that stumped me and I'm like, hmm,
I don't know the answer that right away. I gotta
do some reading, And this one definitely stumped me. Were
you a little offended that they would someone would question
your usefulness in a post apocalyptic scenario. No, I'm a man.
Is that they think that physics could be useful in
the apocalypse. I've often thought of myself as definitely a
(34:05):
luxury of a society. I'm not a blacksmith, and when
the end times come, I don't have that many useful skills,
Like nobody needs calculations done? Are the rates of particle
collisions when you're scrambling to escape the zombies. I definitely
see myself as something supported only by a wealthy society. Well,
I'm an engineer, a mechanical engineer, and actually this question
(34:27):
kind of gives me anxiety. You know, like what if
it's an apocalypse and someone's like, quick, your a mechanical engineer,
make us a water filtration system with a power source,
and be like, um, Like, I could draw you one.
I could simulated using that lab. I could send the
order out to a machine shop. Yeah, it'd be it'd
be kind of difficult. It tells you something about how
far we've come from all being like self sustaining little
(34:49):
societies you know that can live off the land and
do everything for themselves, were so far developed as a
society were so specialized that if society fell apart, a
lot of us would find ourselves useless. All right, So
I guess the question from Lucas is, if you're a physicist,
or if you knew a lot about physics, which one
would you most likely be able to survive? A nuclear
winter or a zombie apocalypse? Yeah, exactly, And so a
(35:13):
nuclear winter, right, that's a scenario where you have a
nuclear war and a large fraction of humanities arsenal of
nuclear weapons get exploded and they send into the atmosphere
a lot of dust and ash and all sorts of stuff,
and then basically you block out the sun. So you
get this layer of cloud which blocks out of the
sun from a significant fraction of the planet, causing an
artificial winter. So it's basically constant winter. Yeah, like a
(35:36):
permanent winter. Like a permanent winter. And you know that
could be like a runaway effect because plants need sunlight,
and without plants to grow, then you're not going to
get food at the bottom of the food chain, and
then US apex predator, US physicists and mechanical engineers won't
have anything to eat, right, And that's trouble because everything
on Earth depends on that solar power, right, I mean,
(35:57):
all the food we eat, all of the weather that
kind of creates rivers and hydroelectric stations, that all depends
on the sun. So if the Sun is blocked, we're
sort of energy less. Yeah, exactly, you are almost literally
pulling the cord on the entire ecosystem if you yank
out the Sun. At the base of it, all is
solar power, gathered by plants or gathered by rocks or whatever.
(36:18):
All of it is in the end solar energy. And
so this is like asking the question, what would happen
if the sun went out? Right? So, then physicists would
be useful because maybe you could make us a new
power source. Maybe we could go into overdrive. I guess
with nuclear power or fusion power. Would that be enough
to kind of sustain a civilization, to grow plants and
things like that. It could, It would be a big effort.
(36:40):
But yeah, there are ways to generate power that do
not rely on the Sun. Obviously, solar power is out.
Even things like wind power, right, are mostly driven by
patterns of wind that come from solar heating. So you
need something like nuclear power. But of course nuclear power
to scale to support agriculture and have massive growth. Farms
would produce an enormous amount of waste. So really, I
(37:02):
think what you would need to do is just accelerate
the fusion research and really try to ramp up fusion
as a source of power, because remember, fusion can provide
electrical power basically just using water as a fuel. All right,
So then physicists would be kind of useful in a
nuclear winter apocalypse, although to be fair, you would have
to also blame them for the nuclear winter apocalypse because
(37:23):
they made the nuclear weapons in the first place. They
designed the nuclear weapons. They didn't drop the bombs, right,
I see, I just made the thing that killed us.
I didn't use the thing that kills No. I joke,
But that's an important question. And you know, my parents
actually both working all those alumos and worked on weapons programs,
and I on purpose became the kind of physicist that
(37:44):
would be totally useless when it comes to weapons development,
because there are real moral complications there. If you are
developing weapons of mass destruction and you know they will
be pointed at cities, then yeah, you could be considered
complicit if they're ever used. Yeah, all right, so then
now let's consider or a zombie apocalypse. Let's say that
zombies are real. What what could a physicists do? Could
(38:05):
they engage in dialogue with the zombies or I don't know,
shoot lasers. Can you develop a zombie killing laser? They
could bore the zombies with calculus lessons or something. Well,
that's the mathematicsies. You're gonna use them for something. I
don't really know, like how a physicist would be helpful here.
Perhaps if the biologists figure out what the zombie weakness is,
then yeah, the physicist could develop some kind of weapon
(38:27):
that could use that weakness, a laser that goes right
to the heart of the zombie brain or something. Or
maybe we could just decide, hey, earth this toast, it's
covered in zombies, it's contaminated, and we need the physicists
to ramp up work on development of terraforming technology for Mars.
I see go there and then have another apocalypse in Mars.
(38:47):
So now we have martians zombies. A second, who's putting
the zombies on the spaceship. It always happens, Daniel, There's
always that one person who gets on board and they're
like coughing and sweaty, and you're like, oh, shoo, let
him in, all right, let him in, and then it
all turns out badly. One scientist who brings some zombie
tissue along, you know, just to study. Yes, yes, scientists agree. Well.
(39:10):
I always wonder in these zombie movies and shows. It's
like it doesn't seem physically possible. I feel like zombies
violate the laws of physics, Like where do they get
the energy? That's true. I mean it's like they never sleep, right,
you know, I certainly can't eat brains for that long
every single day. You mean, like, what's power in the zombie? Yeah?
What's powering? If they're not eating all the time? You know,
(39:30):
they always to zombies like danning around forever. Yeah, where
do they get the calories to move their muscles and things? Like?
Maybe they're solar power. So maybe what you need in
the zombie apocalypse is a nuclear winter to block off
all the solar power so the zombies fail. Or better
you make the zombies into a power source. Instead of
making solar panels, you just have like zombies on a
(39:52):
treadmill and you're just like shoveling zombies into the furnace,
like having empowered like a hamster wheel or something. Right,
you like angle a brain in front of them and
you just get them to walk forever. Yes, alright, better
start thinking of that, Danny, just in case. Okay, all right,
I'll drop some diagrams this afternoon. I'm just desperate to
find a way to be useful in the end time,
so you don't eat me or get eating. I gotta
(40:17):
prove my worth, all right. I think that answer is
Lucas's question, which is most likely a nuclear winter. You
would be useful, but you will also be kind of
partly to blame. Yeah, I'll take it, but there might
be a ways for you to redeem yourself in these
zombie apocalypse I'll do my best, That's all I can promise, Lucas.
All right. So those are our three questions. Thanks to
everyone for sending in their curiosity and their thoughts. Thanks
(40:39):
to everybody for sharing with us you are desired to
understand the universe and for writing to us with those
things that make you wonder. We're here to help you
understand and hopefully not eat you in the end times.
All right. We hope you enjoyed that. Thanks for joining us.
See you next time, ye thanks for listening, and remember
(41:03):
that Daniel and Jorge Explain the Universe is a production
of I heart Radio. For more podcast from my heart Radio,
visit the i heart Radio Apple Apple Podcasts, or wherever
you listen to your favorite shows.
Hey, Daniel, congratulations you're making it to the year. Thanks.
It was a bid harrowing. Wasn't sure we were going
to get here. Our physics is preparing for what might
throw at us. Man, I'm hoping we don't have to.
If we get to the point where we need physics
to save us, it's probably not a small problem. I
guess CERN can't help with the plumbing issues there. You know,
(00:31):
if you want a black hole flush down your pipes,
give us a call. I think we'll save our call
Discern for the big st of you know, like asteroids
and zombie apocalypse. Oh my goshe will probably be the
year of the asteroid zombie apocalypse. That's a new show.
It's called The Orbiting Dead. I am jorheam and cartoonists
(01:06):
and the creator of PhD comics. Hey, I'm Daniel. I'm
a particle physicist and I love all science fiction, except
for zombie apocalypse movies. M That doesn't count as science
fiction to you. No, it counts as science fiction. I'm
just not that into it because you don't like it
or it makes you afraid. I'm not that afraid of zombies,
(01:27):
you know, in real life. But it's just kind of boring.
They're they're always just getting chased by these slowly shuffling
zombies and it's always just like, you know, how many
heads can you explode before they kill you? Oh? Man,
you've been watching the wrong zombie movies. But you know
they run and they climb walls. Now they've upgraded, all right,
I'll look for zombies to point o. Welcome to our podcast,
Daniel and Jorge Explain the Universe, a production of My
(01:49):
Heart Radio in which we tackled the biggest questions of
the universe. We toss our minds into the depths of
space and try to understand where everything is made and
how everything works. We zoom into the littlest particles and
try to wrap our minds around what they're doing and why.
Our goal on this podcast is to literally explain the
entire universe to you, because there is a lot of
(02:11):
a universe to explore, and there are a lot of
mysteries out there, a lot that we don't know about
the universe, about what it's made out of, what's out there,
what can happen, and what is possible in these vast
cosmos we live in. That's right, It turns out even
two hundred and fifty episodes of this podcast is not
enough to explain the entire universe. It's a big place
with a lot of mysteries, and we love talking to
(02:33):
you about it, and we love hearing from you what
you'd like us to break down. Yeah, even after two
d and fifty episodes, people still send us questions. We
get questions through social media, emails to people. Ever to
choke up at your door, Daniel with questions You know
you joke, But when we had classes in person, I
used to hold office hours in person and occasionally a
random person from the street would show up and said
(02:54):
they looked me up and came in with a question
about the universe. So yeah, kind of wow. Is there
a zooming ovalent now? For that, you know, there is
this equivalent. I have monthly public office hours so people
can drop in and ask physics questions. Wow. Cool, All right, Well,
today we are actually addressing listener questions. We are taking
in questions and trying to break them down in fifty minutes.
(03:17):
Because we know that while we do our best to
talk about the mysteries of the universe in a way
that makes sense to you, there's always some angle we
didn't consider something that makes you wonder something that doesn't
make sense to you. So when that happens right to us,
let us know what you're still wondering about, and we'll
break it down for you, either over email or on
the podcast. So on the podcast today we'll be tackling
(03:43):
listener questions Number four teens. Teens are fourteen episode. Yes
we are officially teenagers. I think we were teenagers one
episode ago technically. But yeah, that's a lot of questions
we've answered. Each time we answered like three, so you know,
you would think out the two and fifty episodes, we
would have answered everyone's parties about the universe. Do you
think so? But they keep coming in. So today we
(04:04):
have three awesome questions about black holes, about our favorite topic, aliens,
and our least favorite topic, zombies. That's right, So thank
you to everybody who's sent in questions. And if you
have a question, please don't be shy. Yeah, we love
to get your questions and Daniel loves to answer them.
Will usually answer them, right, I mean you'll usually answer, Oh,
(04:26):
I answer every question. You engage with us on Twitter
or send us an email, you will get a reply.
I guarantee it, but if they don't get a reply,
that means we might be doing it on the show. Right. No, actually,
I right back to everyone. Sometimes people also get a
special podcast episode if I think the question is exciting
enough that everybody might want to hear the answer, Like
if there's zombies, then I would think you want to
(04:48):
stay away from that question. But maybe maybe physics will
save us from zombie. We'll see, all right. Well, the
first question is about black holes, and it comes to
us from Patrick from Nashville, Tennessee, Daniel, and Jorge. My
name is Patrick oh Leary from Nashville, Tennessee. I have
a question for you guys. I was curious what would
the chemical or elemental makeup of a black hole consists of.
(05:09):
If our son is made of hydrogen elements fusing into helium,
and if other life stages of stars include heavier elements
fusing and so forth leading up to this big collapse,
wouldn't it seem reasonable that a black hole will consist
of some super heavy element resulting from some sort of
hyperfusion occurring during and after the gravitational collapse. Would there
(05:33):
be an element that doesn't fit on the periodic table?
That may have some sort of infinite density. Would it
even be an element or would this singularity potentially be
something entirely different? Is there something else that this matter
in the black hole could theoretically be. I just want
to see what y'all thoughts are. We really enjoy the
show and uh look forward to hearing your answer. Thanks. Well,
(05:56):
that's a super heavy question from Patrick. Yeah, it's an
awesome question thinking about weird places in the universe that
can make weird kinds of matter. So super awesome question,
thanks Patrick. Yeah, I guess the fundamental question is what
is a black hole made out of? We know it's black.
It's I mean, it's made out of like charcoal. It's
(06:19):
just an aluminum sphere with black paint on it. I mean,
sorry to break everybody's bubble here, but that's all it is.
It's fake news exactly. It's fake physics news. Huh. I
can see his reason in there. It's pretty interesting and
pretty convincing. Like if you think about heavy objects in
our universe, like stars there made out of hydrogen and
(06:40):
things are fusing inside and gravity is crushing them down
and they get older and explode and come back together.
They're making heavier and heavier elements, and so does that
mean that when you get to the ultimate dense object,
does that mean it's made out of super heavy elements. Yeah,
this is a super fun question. I thought it'd be
fun first to think about, like what is the mass
(07:01):
of the stuff that turns into the black hole, like
just before it becomes a black hole? What mix of
stuff do you have there? And then we can talk
about what happens to it as the black holes collapsing,
Like does it form some new weird state of matter?
Could you even call that an element? Etcetera, etcetera. Oh,
I see, like the scene of a murder. Let's go
let's go back to right before the actual event and
(07:23):
see what conditions are there, and then maybe that would
tell us what happens when the actual black hole forms. Yeah, exactly.
We're not murdering any iron here. I think of it
more like cooking, you know, And we want to make
sure we understand what are the ingredients we're just killing irony,
We learned straight to the answer that's right, or we're
cooking it up one of the two. All right, Well,
he mentioned stars because a lot of black holes come
(07:45):
from stars, right, and stars collapsing or super annobody. Yeah,
and so there's two categories of black holes. They're the
super massive ones at the centers of galaxies. But let's
focus on the other ones, the smaller ones that are
stellar black holes. And this happens when you have a
star and it gets too heavy and the gravity sucks
it in and eventually becomes a black hole. And he's
totally right that this is where heavy elements are made.
(08:07):
I mean, the universe started with mostly hydrogen, and the
way you get heavier elements is that you fuse hydrogen
nuclear together to get helium, and then helium together to
get heavier stuff, and you work your way up the
periodic table, eventually getting to iron. And so in the
center of stars are these conditions to take two elements
and turn them into a new element. Right, the amazing
(08:28):
thing that we once thought it was impossible, alchemy actually
happens all the time at the centers of stars, creating
new kinds of matter. So that happens in our universe.
That's pretty awesome, Yeah, because the elements are just different
combinations of the same three things, right, quarks and electrons,
and so you know, if you if you get something
that has three quarks and two electrons, and you compress
(08:50):
it with something that has four quarks and another three electrons,
and you get something that's additive. Right, yeah, exactly, You
just add them together and to make a new element, though,
what you need to do is to add a new
proton to the nucleus, Like a typical atom has protons
and neutrons, which of course are made of quarks in
the nucleus and then surrounded by electrons. To get to
a new element, like to go from helium to lithium
(09:12):
or something, you need to add protons, change the charge
of the nucleus, and then add more electrons to make
it neutral. The other thing you can do is add neutrons. Right,
If you add neutrons, that doesn't change the element, just
changes the isotope. Right. You've heard of like uranium two
thirty eight or uranium two thirty five. That tells you
how many nucleons are in the nucleus. They're both uranium
because they have the same number of protons, but they
(09:34):
have a different number of neutrons, right, And so that's
what's happening inside of stars, is that you're making these
heavier and heavier elements, but only up to a certain point, right,
Like you can build it up through carbon and silicon,
but then you get to iron. Yeah, exactly, if you
want to make super heavy elements, you can keep doing
that fusion process, but only up to iron. Up to iron,
(09:55):
it releases heat, and so it drives the reaction and
makes it happen more and more. Above of iron, it
absorbs heat. So you confuse to iron nuclei together to
make something heavy, but it costs you heat, and so
it cools down the star. And that's why stars that
build up too much iron inside them collapse and form supernovas,
because it's the pressure from that heat that keeps the
star from collapsing. So if the fusion actually causes the
(10:18):
star to cool down, then it's actually encouraging it to collapse.
It's working in the same direction as gravity, rather than
pushing out against it. And so that's why stars collapse
after they get it big enough iron core, right, And
when these stars collapse, that's when you get the heavier elements,
right because of the explosion or what Well, actually, that's
something we've only recently understood. For a long time, people
(10:39):
thought that you've got the heavier elements gold and platinum
in that collapse or in the supernova that happened just afterwards,
because they thought maybe the conditions were crazy hot enough
in the supernova to force extra neutrons onto an iron
and then those neutrons would decay into protons and you
end up with a heavier element. But it turns out
that's not the case. That most of the gold and
(11:01):
the platinum and the heavy stuff in the universe is
not actually made in supernovas. Yeah, and they learned this
because they found bits of supernova in the ocean. What crabs,
What does a bit of supernova look like? Yeah, Well,
on the outer layers of the supernova are these little
seeds like heavy elements, which then get covered and stuff
(11:21):
from the supernova and blown out into space. And these
are special little grains which you can later identify. And
like our Solar system is made up literally of star dust, right, well,
some of that star dust are these little grains from
supernova and you can find them and you can study them,
and they've looked at them and they've tried to understand
whether they have evidence in those grains for the formation
(11:42):
of heavy elements. Is like particular signal you need that
shows you that heavier elements were made during the supernova expansion,
and they don't see them. Right, you need this marker.
It's plutonium two forty four, and they just don't see
them in these grains that they find buried in the
ocean crust. But now we have another candidate for how
we those super heavy elements were made. What's a candidate? Well,
(12:03):
instead of being created during the supernova, we think that
sometimes these stellar collapses lead to neutron stars, these very
very dense objects. They're not heavy enough to collapse all
the way to a black hole, but are heavy enough
to be this crazy new form of matter just neutrons.
And sometimes those neutron stars can collide, they can find
each other in a binary system, and they can spiral
(12:24):
in and form this collision and those of the conditions
you need to make gold or platinum or these super
heavy elements. What that's wild? Wait, so I know neutron
star is just like a giant mass of neutrons. Right,
you don't even have elements or atoms. It's just all neutrons.
It's just all neutrons. It's like some new element that's
pure neutrons and new protons. It's a weird form of
(12:45):
matter that frankly, we don't understand very well. And so
you're saying, and sometimes two of those collide, like crashing
to each other, and then when in the crash they
create elements, or when they break apart, they create new elements.
In the crash, they create those months, and the fact
that there's a collision sprays those elements out into the universe,
which is why now we find those elements on Earth.
(13:08):
For example, most of the gold and the platinum on
Earth we think is produced in the collisions of neutron
stars billions of years ago. Wow, that's a weird sentence.
Neutral collision, like a collision that doesn't care. It's amazing
because it means that formation of gold and platinum is
(13:28):
much more rare than we thought. Neutron stars don't collide
as often as you have supernova, but when you do
have a neutron star collision, you make a lot more
of these heavy elements than you would in a supernova. So,
for example, we used to think that supernova collapse is
produced about one moon's worth of gold. That's a pretty
big chunk of gold. And we think like the universe
(13:49):
was sprinkled with all these basically moons of gold. But
now we think that it happens more rarely. But when
it happens, when you get these neutron star collisions, you
get like a Jupiter of gold. Whoa, that's a lot
of blink And so it's more like the universe is
sprinkled with these really big chunks of gold rather than
more like evenly distributed with little, you know, sprinkles of gold.
(14:10):
It's like chocolate chip cookies rather than chocolate sprinkles. All right,
so let's get made back contract of the black hole.
So that's how we get heavier elements in maybe nutron
stark collisions. But then do those neutron stars become black
holes or not? No, they usually just get torn apart.
Sometimes if they get over the threshold, they can turn
into black holes, but not all the time. Most of
(14:31):
the black holes that are out there, these stellar mass
black holes, start out as sort of larger suns like
ten to fifteen stellar masses, which then threw a lot
of fusion, builds up a heavy iron core, and collapse
straight to a black hole. And so they're potentially you
can imagine heavier stuff being made or weird forms of
matter being made in a supernova in the supernova which
(14:53):
leads to the collapse into a black hole. Yeah, oh,
I see. So there are heavy elements due to neutron
stark collisions. But when you get a black hole from
a collapsing star, you may also make heavy elements. You might.
I mean, it's not something we understand very well. And
you know, let's think about the ingredients you have there. Say,
for example, you start with like ten solar masses of stuff.
(15:15):
You have a big sun which makes a heavy iron nucleus,
and then it collapses. You might be imagined that you
start with ten solar masses of iron, but it collapses
before it turns the entire mass to iron. So you
probably have like a heavy core there that's like one
or two solar masses worth of iron that forms the
sort of gravitational center that leads to the black hole.
(15:36):
So you've got a lot of iron there, and then
you've got a lot of other in rushing matter during
the collapse exactly, And those are the conditions you need
to make new kinds of matter. Right, you have iron,
which is very heavy, and then you have a lot
of protons and neutrons coming in. But it's a very
strange situation. I mean, it's like much denser and much
hotter than even neutron stars. So I think that's the
(15:57):
guide you might be imagining. You have iron, and you
have all these other particles, and you're adding them together,
you might be making heavier elements instead. Typically what you
make are not elements like what we recognize, but weird
new forms of matter like you see in neutron stars, right,
because you need to get to the right density to
create the black hole, right, So at some point you
(16:17):
do need to sort of create this weird kind of
super heavy mass. Yeah, exactly. Formation of new elements requires
that you take a nucleus, you add protons to it,
and then you sort of like let it go off
by itself and be stable. Here we're taking the results
and we're squeezing it down really intensely, So all the
protons are just going to turn into neutrons because they're
gonna get an electron squeezed into them, and then most likely,
(16:38):
instead of forming weird new elements, you're gonna get really
strange neutron rich matter, you know, strange new kinds of matter.
We haven't even imagined weirder things than neutron stars. Right.
Maybe the answer then is that in a black hole,
or at least as you're getting into a black hole,
like regular elements can exist, Like you can't have an
element where it's like neutrons and pro autons and electrons.
(17:01):
It's like it's the conditions are so extreme. Everything is
compressed into this weird new type of matter. Yeah, exactly,
and the distinction between like this atom and that atom
breaks down when the atoms get so close together and
get so pushed on each other. What you're really going
to get is some sort of like weird fluid of
neutrons and protons and electrons, and that's going to get
compressed into something even weirder, and you might get, for example,
(17:23):
like a quark gluon plasma where the quarks are no
longer bound even into neutrons and protons because they're so
dense and intensely pressured. So basically you're like recreating the
conditions of the early universe sort of in reverse. Wow.
All right, well that's just leading up to the creation
of the black hole. Let's get into what might be
inside of it once the black hole is made. But first,
(17:44):
let's take a quick break. All right, we're answering listener
quite Shans, and our first question was about what element
is a black hole made out of? Like is it
(18:05):
some kind of new kind of super heavy element. And
it seems like, at least going into the black hole,
we don't have actual elements. By the time you're you're
dense enough to create a black hole, you're in this
weird state of matter. Yeah, because elements are not fundamental, right,
They're not like a basic thing in the universe. There's
sort of like a special configuration of quirks and electrons
that require certain conditions, you know, certain temperatures, certain densities,
(18:28):
and if you get hot enough and you get dense enough,
then you just don't have elements anymore. So it doesn't
really make sense to talk about like is this plutonium,
is this uranium, is this black holium? It's some new,
other weird kind of matter black holium like that it
sounds holy. All right, Well that's before you go into
the black hole. So like at the core and like
the time of birth, the black hole is probably at
(18:50):
the core made out of this weird super heavy neutron soup.
But what about like after it forms like boom, suddenly
I have a black hole and you know, stuff keeps
falling into it. What can we say then about what
it's made up? Like if it grows, then it's probably
not mostly this neutron soup. That's right. We're talking about
the super dense conditions that are going to be like
at the very core of the black hole. What's sort
(19:12):
of like on the outskirts of the black hole, just
inside the event horizon, for example, but not super close
to the very dense material at the center that's maybe
forming a singularity. Well, we think that inside a black
hole space mostly works the same way as it does
outside the black hole, except that it's sort of like
oriented towards the center. So, for example, if you toss
(19:33):
a banana into a really big black hole one where
the spaghettification doesn't happen until you get close enough to
the center, it'll just pass over the event horizon and
continue drifting in towards the singularity. From its point of view,
there's nothing special there at the boundary, it'll still be
a banana. But for how long? First of all, they
nat gets spaghettified, and does that sped getification also kind
(19:56):
of get rid of elements. Does it? Is it a soup?
Is it a bananas By the time it goes in,
It's definitely a banana smoothie by the time it goes in.
When you take a banana, you make it into spaghetti
and then you put that spaghetti in the blender and
you get a smoothie banana spaghetti. That's probably very popular
in Italy. What kind of sauce or wait, can you
(20:17):
put parmesan cheese on banana spaghetti? It's gluten freedom. As
you approach the center of the black hole, that obviously
the tidal forces are going to be very, very strong.
That's the difference in the gravitational force between one side
of the banana and the other side of the banana.
That's what's responsible for the spaghettification. It's going to pull
it apart, and then as it gets closer and closer,
(20:38):
those tidal forces get stronger and stronger, pulling those little
bits of the banana apart further and further, and eventually
it's got to hit some really dense part of the
black hole, someplace where the matter is really dense, and
then it'll just you know, join whatever that is, whatever
that is Is that an official element in the in
your physics table. That's the official way of us saying,
(20:58):
we really just have no idea what's going on at
the center of the black hole. So yeah, whatever that is.
So then that's kind of the real answer, because all
these things that we think are might be happening beyond
even horizon, we don't really know right for sure, We
don't really know for sure. And the sort of two
directions in which we don't know, Like we don't know
from a sort of nuclear physics theory perspective, what happens
(21:20):
if you squeeze neutrons together even harder than the conditions
of a neutron star, Like we can't do those calculations
right now for a neutron star, Like we can't sit
down on a computer and simulate a neutron star because
the calculations are too difficult. So even heavier than that,
even crazier conditions that we also cannot do. Also from
a sort of like black hole theory point of view,
(21:41):
we just don't know what the distribution of matter is
inside the black hole. General relativity says there's a singularity
of infinite density, but we know that doesn't really make sense,
and the quantum mechanics says it's impossible. So there's a
lot of questions about what's going on at the heart
of the black hole, not just like what is the
matter made out of? Once you get there? All right, Well,
it sounds like the answer for Patrick is that a
(22:04):
black hole is made out of We have no idea
exactly or black holio. It's kind of a mystery, but
we know that when you make a black hole, it's
not like an element. There aren't any elements inside. It's
more like this kind of hot mess of a soup
of neutrons. Probably probably exactly. All right, let's jump into
(22:26):
our next question, which is about aliens from space. So
we have a question from Ignacio, and he's from Jupiter.
Is that Jupiter Florida? Uh No, I'm not sure if
he's talking about Jupiter Florida or Jupiter the Solar System.
He might actually be an alien, in which case, why
is he asking us? All right, everybody, get ready to
listen to the first message from alien. His name is Ignacio.
(22:51):
There is this question, Hi from Jupiter. Apparently my question
is that, well, we are always wondering it would be
to receive my search from an advanced aliens realization. But
if we were to discore in disputable evidence of an
abilience relization existing different way planet that is roughly equal
(23:12):
to us in technology, how could we send them a message?
How will we make ourselves known to them? All Right,
that's a pretty cool question. The question is if we
ever find evidence of aliens, like if we get a
signal from far away or like we figure out the
aliens out there, how can we ever reach them or
a column or or text them or send them at
(23:35):
d M. Yeah, that's a really fun question. I mean
I always like to think about what would be like
to get that message, But then it's really interesting to wonder,
like how could we respond with technology is available to us?
And what should we say? Yeah, like, I guess if
you find that they're aliens, like you know, the next
star over like four light years away or thirty light
years away, Like, do we have technology that can beam
(23:58):
a message that far know? We do, or at least
until very recently we did. We probably heard of the
Arecibo radio telescope. That antenna can receive messages, but it
can also send messages out into space. It's a giant
like dish wouldn't we want something more I guess focused
or can that do? Like a focused beam of message? Well,
(24:19):
the dish allows you to basically capture a bunch of
the messages put out by the antenna and focus it
all in the same direction. That's the idea behind a
parabolic dish is that it bounces off the message from
the antenna all in a parallel direction, so allows you
to create a directional beam. And a directional beam would
be very very important. Otherwise the power of your message
(24:39):
would fall really really quickly as it got further and
further from Earth, right like if you transmitted like in
a broadcast antenna, it would just kind of spread out
in all directions and by the time it gets to
you know, thirty light years away, they probably couldn't hear it. Yeah, exactly,
just like a candle in the dark. It's very bright
close up, but it falls off like one over distance squared,
(25:00):
and so twice as far away it's one fourth the intensity,
and a hundred times away it's one ten thousands the intensity.
And so I've actually done this calculation to figure out
how far away could an alien planet be for us
to hear a message using Arecibo, and it turns out
that if they have an air cebo sized telescope and
they're broadcasting in every direction, we would have to be
(25:21):
within a one light year of their planet to hear
it with our air cbo telescope. That's not good enough,
because we're we're further away from that. That's right. There
are zero stars within one light year of Earth. So
basically for us to get a message from another solar system,
they would either have to broadcast it in all directions,
much more powerfully than our technology could, much more powerfully
(25:42):
than air cbo could broadcast, or they would have to
beam it at us directly, which means they would have
to know we're here and send it to us intentionally.
Now can you do that? Can you stand out an
electromagnetic signal in a focus way, kind of like a laser? Sure, exactly,
you could use a laser for example. I mean, radio
waves are just a kind of light. A laser also
(26:04):
sends out a beam of light, So it's just a
question of like what frequency do you want to use?
The best way to communicate through the universe is to
choose a frequency that's not easily scattered or distracted or
absorbed by other stuff, and so things in the radio
spectrum are actually a great way to communicate. Is there
such a thing as a radio laser? Can you shoot
like a radio beam? Actually? Yeah, there are people working
(26:26):
on building semiconductors capable of generating radio frequency laser beams,
so that would be super cool. That's one way to
communicate with aliens is to send them a message basically
using electromagnetic radiation, which means, you know, light or ultraviolet
or infrared or radio somewhere on the spectrum, pick something
(26:47):
that is sort of quiet in the universe. But you know,
if we get a message from aliens, then we should
respond basically in the same way that they wrote to us. Right.
If you get an email, you don't then send somebody
a text? Why not? That's totally inappropriate. Man, If you
get a text right back with text, you get a
phone call, you don't write somebody a letter in response, right,
(27:08):
So if somebody sends us a message via e M waves,
you know, radio message, then we should respond in the
same frequency. Right. But I guess the problem might be
that maybe we got it in one way, but we
don't have anything powerful enough to send it the same way. Back. Yeah, well,
I guess that would make a pretty good case for funding, right, Like, hey, look,
we got this message, although you know, I'm not sure
(27:29):
it's such a great idea to respond to aliens. You know,
we don't know these folks at all. It's like, do
you pick up the phone when you get a number
you don't recognize? Not all the time. That depends how
bored ant anyway, and how lonely I am, and depending.
I mean, imagine that we're out there in the universe
and we've just become technologically savvy enough to get these messages.
(27:49):
We're probably the youngest civilization out there because we've just
burst on the scene, and so we'd be a pretty
easy mark, you know. Alright, well, so be mean with
some sort of radio laser would be our main options.
We have any other options to send the message out Well, basically,
it's just all kinds of radiation, and the kinds of
radiation that can transmit through space are either photons or
(28:10):
other kinds of particles. So we could imagine, for example,
shooting a beam of particles at an alien star and
use that as a way to send messages, you know,
like Morse code via neutrinos for example. M I wonder
if the problem would be, like, if we shoot a
laser at an alien civilization, would they interpret that as
a as an act of war or something? You know
(28:32):
what if they don't get the message, what if it
just goes over their head and they're like, they're shooting
at us. Well, I would encourage us to not use,
for example, Morse code in nuclear explosions. But I think
that a laser beam would not be interpreted as an
active warming. By the time I guess to them, it's
going to be so faint they would have even trouble
picking it up. So if they interpret that as an
act of war, then they were just looking to start something.
(28:54):
I see they're happy, in which case maybe we shouldn't
be something exactly exactly all right, So it sounds like
the answer is we have the technology to write to
any aliens folziation, and we've done it. In fact, in
the seventies, there was a really weird message that we
saw come from space. It's called the Wow signal because
nobody understood it. And at the time that we saw
(29:14):
this message come in, some astronomer wrote wow on the
transcript of it as it printed out from the like
old school printer, and we got this and it came
from space, and we don't understand it. We don't know
was it Aliens, was it just some weird new kind
of star. Nobody's ever understood it because it's never been repeated.
It was just a one time event. But we drafted
a response and sent it out back in the direction
(29:36):
of the signal, hoping maybe someday somebody would read it.
What do we say in this message? Up, we said,
new phone. Who did know? What we did is we
communicated something about where we live and how our life works.
We showed them our number system, We described the basics
of our chemistry. There's a little illustration of the shape
(29:58):
of the human body, and and then the sort of
directions to the solar system. Well everything a alien species
would need to come and conquer us, basically all of
our passwords, our biggest weaknesses save words exactly, our elementary
school teacher, all that stuff. Yeah, it was sort of
a naive message, but it's sort of like hopeful, you know,
(30:21):
we hope that somebody reading it would understand it. And
in this spirit of exploration of the universe and physics
and whatever, come and send us a message back and
tell us something about their civilization. All right, so we
sent out using the RCIBOW antenna, and do we think
it made it or do you think it's too weak?
By the time it gets there, it might be too weak.
(30:41):
But we don't know what their technology is. But it
won't get there for quite a while. We don't know
who's out there and maybe receiving that message. But the
message came from something called M thirteen, a globular cluster
that's about twenty five thousand light years away, so it's
going to take a while before it gets there if
that's where their original message came from. All right, it
sounds like we have options for sending messages neutrinos or
(31:04):
radio telescope or maybe these radio lasers. But you were
telling me there is one way right now, if you
want to broadcast a message out into space, there is
a way to do it. It turns out that if
you use Craigslist, there's an option on Craigslist to broadcast
your message out into the Solar System. No what, seriously,
the CEO of Craigslist, this guy, Jim Buckmaster, bought a
(31:25):
bunch of time on the deep space communication network this
place in Florida that can broadcast into space. So they're
picking ten thousand ads to broadcast into space. So if
you're having a garage sale and you think, you know,
maybe Ignacio from Jupiter should come by and check out
what you're selling, then hey, click the button and Craigslist
will advertise in space. Wow, that's crazy. So not only
(31:50):
are we inviting people to to come attack us, reminding
them to come rate our garages. Like, I don't want
my junk to just reappear somewhere else in the neighborhood.
I want it off planet. Well, we do have a
lot of junk, and it would be good if evan
alien came and took away all of our our unused
and outdated toys. Hey, one species junk is another species gold, right,
(32:11):
so yeah, maybe they love all televisions and satellites. All right, well,
thank you Ignacio from Jupiter for that question. And now
let's get into our last question about zombies. But first
let's take a quick break. All right, we're answering listener questions,
(32:40):
and our last question here is it's sort of debatable
whether it's a physics question at all. Maybe I don't
know you have a question from Lucas from Finland. Hello,
Daniel and Harney, Greetings from Finland. This is Lucas. Have
a question, Um, which would you more likely survive using
physics and nuclear winter or a zombie be apocalypse? Wow? Yeah,
(33:02):
I guess the question is in an apocalypse, what are
physicists useful for besides food? Maybe? Like if you had
a physicist in your little, you know, survival group, are
they an acid or are they allowed a liability? When
you say food, you mean to cook the food right
as a chef, right, not as a source of sustenance.
(33:22):
That's what I'm assuming you're talking about here, you know,
and the apocalypse. You know, you gotta You're gotta be
flexible when you're thinking. You really learned who's your friend
when the apocalypse comes? And who's your dinner? I really
learned from shows like The Walking Bead. Maybe I should
watch some of those shows. You want to be prepared.
This is a fun question because I often put questions
(33:44):
on the podcast that stumped me and I'm like, hmm,
I don't know the answer that right away. I gotta
do some reading, And this one definitely stumped me. Were
you a little offended that they would someone would question
your usefulness in a post apocalyptic scenario. No, I'm a man.
Is that they think that physics could be useful in
the apocalypse. I've often thought of myself as definitely a
(34:05):
luxury of a society. I'm not a blacksmith, and when
the end times come, I don't have that many useful skills,
Like nobody needs calculations done? Are the rates of particle
collisions when you're scrambling to escape the zombies. I definitely
see myself as something supported only by a wealthy society. Well,
I'm an engineer, a mechanical engineer, and actually this question
(34:27):
kind of gives me anxiety. You know, like what if
it's an apocalypse and someone's like, quick, your a mechanical engineer,
make us a water filtration system with a power source,
and be like, um, Like, I could draw you one.
I could simulated using that lab. I could send the
order out to a machine shop. Yeah, it'd be it'd
be kind of difficult. It tells you something about how
far we've come from all being like self sustaining little
(34:49):
societies you know that can live off the land and
do everything for themselves, were so far developed as a
society were so specialized that if society fell apart, a
lot of us would find ourselves useless. All right, So
I guess the question from Lucas is, if you're a physicist,
or if you knew a lot about physics, which one
would you most likely be able to survive? A nuclear
winter or a zombie apocalypse? Yeah, exactly, And so a
(35:13):
nuclear winter, right, that's a scenario where you have a
nuclear war and a large fraction of humanities arsenal of
nuclear weapons get exploded and they send into the atmosphere
a lot of dust and ash and all sorts of stuff,
and then basically you block out the sun. So you
get this layer of cloud which blocks out of the
sun from a significant fraction of the planet, causing an
artificial winter. So it's basically constant winter. Yeah, like a
(35:36):
permanent winter. Like a permanent winter. And you know that
could be like a runaway effect because plants need sunlight,
and without plants to grow, then you're not going to
get food at the bottom of the food chain, and
then US apex predator, US physicists and mechanical engineers won't
have anything to eat, right, And that's trouble because everything
on Earth depends on that solar power, right, I mean,
(35:57):
all the food we eat, all of the weather that
kind of creates rivers and hydroelectric stations, that all depends
on the sun. So if the Sun is blocked, we're
sort of energy less. Yeah, exactly, you are almost literally
pulling the cord on the entire ecosystem if you yank
out the Sun. At the base of it, all is
solar power, gathered by plants or gathered by rocks or whatever.
(36:18):
All of it is in the end solar energy. And
so this is like asking the question, what would happen
if the sun went out? Right? So, then physicists would
be useful because maybe you could make us a new
power source. Maybe we could go into overdrive. I guess
with nuclear power or fusion power. Would that be enough
to kind of sustain a civilization, to grow plants and
things like that. It could, It would be a big effort.
(36:40):
But yeah, there are ways to generate power that do
not rely on the Sun. Obviously, solar power is out.
Even things like wind power, right, are mostly driven by
patterns of wind that come from solar heating. So you
need something like nuclear power. But of course nuclear power
to scale to support agriculture and have massive growth. Farms
would produce an enormous amount of waste. So really, I
(37:02):
think what you would need to do is just accelerate
the fusion research and really try to ramp up fusion
as a source of power, because remember, fusion can provide
electrical power basically just using water as a fuel. All right,
So then physicists would be kind of useful in a
nuclear winter apocalypse, although to be fair, you would have
to also blame them for the nuclear winter apocalypse because
(37:23):
they made the nuclear weapons in the first place. They
designed the nuclear weapons. They didn't drop the bombs, right,
I see, I just made the thing that killed us.
I didn't use the thing that kills No. I joke,
But that's an important question. And you know, my parents
actually both working all those alumos and worked on weapons programs,
and I on purpose became the kind of physicist that
(37:44):
would be totally useless when it comes to weapons development,
because there are real moral complications there. If you are
developing weapons of mass destruction and you know they will
be pointed at cities, then yeah, you could be considered
complicit if they're ever used. Yeah, all right, so then
now let's consider or a zombie apocalypse. Let's say that
zombies are real. What what could a physicists do? Could
(38:05):
they engage in dialogue with the zombies or I don't know,
shoot lasers. Can you develop a zombie killing laser? They
could bore the zombies with calculus lessons or something. Well,
that's the mathematicsies. You're gonna use them for something. I
don't really know, like how a physicist would be helpful here.
Perhaps if the biologists figure out what the zombie weakness is,
then yeah, the physicist could develop some kind of weapon
(38:27):
that could use that weakness, a laser that goes right
to the heart of the zombie brain or something. Or
maybe we could just decide, hey, earth this toast, it's
covered in zombies, it's contaminated, and we need the physicists
to ramp up work on development of terraforming technology for Mars.
I see go there and then have another apocalypse in Mars.
(38:47):
So now we have martians zombies. A second, who's putting
the zombies on the spaceship. It always happens, Daniel, There's
always that one person who gets on board and they're
like coughing and sweaty, and you're like, oh, shoo, let
him in, all right, let him in, and then it
all turns out badly. One scientist who brings some zombie
tissue along, you know, just to study. Yes, yes, scientists agree. Well.
(39:10):
I always wonder in these zombie movies and shows. It's
like it doesn't seem physically possible. I feel like zombies
violate the laws of physics, Like where do they get
the energy? That's true. I mean it's like they never sleep, right,
you know, I certainly can't eat brains for that long
every single day. You mean, like, what's power in the zombie? Yeah?
What's powering? If they're not eating all the time? You know,
(39:30):
they always to zombies like danning around forever. Yeah, where
do they get the calories to move their muscles and things? Like?
Maybe they're solar power. So maybe what you need in
the zombie apocalypse is a nuclear winter to block off
all the solar power so the zombies fail. Or better
you make the zombies into a power source. Instead of
making solar panels, you just have like zombies on a
(39:52):
treadmill and you're just like shoveling zombies into the furnace,
like having empowered like a hamster wheel or something. Right,
you like angle a brain in front of them and
you just get them to walk forever. Yes, alright, better
start thinking of that, Danny, just in case. Okay, all right,
I'll drop some diagrams this afternoon. I'm just desperate to
find a way to be useful in the end time,
so you don't eat me or get eating. I gotta
(40:17):
prove my worth, all right. I think that answer is
Lucas's question, which is most likely a nuclear winter. You
would be useful, but you will also be kind of
partly to blame. Yeah, I'll take it, but there might
be a ways for you to redeem yourself in these
zombie apocalypse I'll do my best, That's all I can promise, Lucas.
All right. So those are our three questions. Thanks to
everyone for sending in their curiosity and their thoughts. Thanks
(40:39):
to everybody for sharing with us you are desired to
understand the universe and for writing to us with those
things that make you wonder. We're here to help you
understand and hopefully not eat you in the end times.
All right. We hope you enjoyed that. Thanks for joining us.
See you next time, ye thanks for listening, and remember
(41:03):
that Daniel and Jorge Explain the Universe is a production
of I heart Radio. For more podcast from my heart Radio,
visit the i heart Radio Apple Apple Podcasts, or wherever
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Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
Popular Podcasts
United States of Kennedy
United States of Kennedy is a podcast about our cultural fascination with the Kennedy dynasty. Every week, hosts Lyra Smith and George Civeris go into one aspect of the Kennedy story.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.