October 3, 2019 • 35 mins
What do we know about fermi bubbles?
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Speaker 1 (00:08):
If I told you that today we're talking about bubbles,
what comes to mind? I'm thinking of bathtime. Are you
in the bath as we're recording this. I'm just worried.
I listened to the Higgs boson. I think that rubber
duck ees might destroy the universe. All right, well, I
want you to think bigger than just your bathtube. Okay,
like those hula hoop bubbles that you make with your
(00:30):
kids in this classic bath that's the right direction. But
go bigger, bigger than that. Then you've got to be
talking about like our atmosphere or something as a huge
bubble around the whole ward, even bigger. Can a bubble
be that pig? Can you even think about a bubble
that big? Or is it gonna blow your mind? Hi?
(01:06):
This is Daniel. I'm a particle physicist and the co
author of the book We Have No Idea, A Guide
the Unknown Universe. My other co host and co author
is Jorge cham, a cartoonist and a friend of mine.
Jorge is not here today, so we have a guest host,
Professor Matt Georgianni of the University of Maryland. Say Hi
to everybody. Matt, Hello, everybody. Yeah, I'm Matt Georgiohnny, And
(01:29):
I'm a biologist, so I don't know anything about physics
unless it makes animals. Biology is basically just big physics, though,
isn't it It is? I mean, it's biologist what physicists
which they could study to lay the gauntlet down. Now, Wow,
I thought you were admitting that biology is nothing but
(01:50):
an emergent phenomenon of physics. But now it seems you're
trying to turn the tables on me. It won't be
the first time, So tell everybody a little bit about yourself, Matt.
Why are you a biologist? What do you study? What
do you find fascinating? I loved mathematics early on, in
in high school and in college, but I got really taken.
Loved is in past tense. I loved, I still love,
(02:11):
But I got really taken with evolution. And I loved
how big, you know, animals evolved into different shapes and beings,
and how all of life on Earth came to be.
And I just find it utterly fascinating. You mean the
theory of evolution, right, the theory of evolution, yes, but
what a wonderful theory right up there with the theory
of gravity. Two of my favorite theory. Oh snap, snap,
(02:34):
all right, I will I'll take that blow touchet. So
do you study evolution in your research? I do. I
study rattlesnake venom actually, and how that has evolved across
different types of snakes. Wow? So how many years until
humans evolve venom that we can squirt out of our teeth? Man?
I am keep waiting. Every day I check my teeth
(02:54):
and I haven't done it yet. What do you mean waiting?
If anybody's going to develop that technology, it's going to
be you. We are waiting for you to develop it. Matt. Well,
I'm working on it. I'll get there. Have you tried
getting bitten by a radioactive rattlesnake? I feel like now
this is why I called you. Now I can finally
complete my research. Al Right, Well, I want authorship or
(03:15):
at least acknowledgement on the paper where you announced that.
Give me my first bite? How about that? That's a deal.
That's a deal. All right? Well, welcome you are our
co host today our guest host on the podcast Daniel
and Jorge explain the Universe featuring Today Matt Georgianni. So
I guess it's Daniel and Matt explained Daniel and Jorges
universe or I'm not sure what the temporary name should be,
(03:37):
or maybe I can just work up what you guys explain.
That's right. Daniel tries to explain the universe and Matt
confuses everybody. That's right. And our podcast is a production
of I Heart Radio. Today we're gonna be talking about
all those amazing things that you do go into science
to discover. You went into science to talk to discover
evolution and unravel the secrets of the history of life.
And I went into physics to reveal a deeper truth
(03:59):
about the nature of the universe. And as always when
you jump into something scientific, you never know what you're
going to discover. And today's episode is going to be
all about that, about unexpected discoveries. What's the most interesting
or famous unexpected discovery in biology or in rattlesnake venom.
I can only say that one of the things about
biology is that we as we keep discovering things, we
(04:21):
the conclusion is always that everything is way more complicated
than we ever thought it was. Oh, I see, so
we're like, hey, we evolved from primates. There must be
a straight, dotted line between us and some common ancestor
of chimps, and then we dig up a bunch of
fossils and they don't make a nice dotted line. I
think human evolution is one of these great cases where
we did kind of think maybe there would be a
(04:43):
sort of simple line, and all we keep learning is
that populations of early humans and different hominids were intermingling
and mixing, and that the modern human that we that
what we envision is actually this really complex mixture of
a bunch of different populations of humans and early humans
and we're just way more complex than we ever thought
(05:05):
we were. And do you think that's like a really
fun moment when you're, you know, digging up a skeleton
that doesn't look anything like the one you expected to find,
because that opens the doors to crazy new ideas. Or
do you think it's like frustrating. We're like, look, I
just got to graduate, I want to write this paper,
and now this data doesn't make any sense to me.
I think it it's a little of both. I think
(05:26):
the first time you realize it's not the answer you expected,
you think, oh great, I was really hoping I could
wrap this up, and then your mind starts to click
and you start to think of all the other new
questions you suddenly have, and then all of a sudden,
the world just becomes that much bigger. And that's that's
really a fun moment. Yeah, And I think there's an
analogy there. I think like the progress of science in
(05:46):
general is something like the weird, complicated mess of human evolution.
You know, we make progress in this direction, and we
got to back up and go this other way, and
then we stumble across this thing, and then the end
we draw some conclusions based on this big mess combination
of ideas, this population of discoveries. Yeah. And so today
on the podcast, we'll be talking about an amazing discovery
(06:08):
that was made very recently, within the last ten years, uh,
something which totally changes what we know about the very
galaxy we live in. I love that physics is still
discovering things. You thought physics was used up like a
hundred years ago, But I thought that Einstein and Newton
had figured it all out. No, No, not at all.
So today on the podcast, we'll be answering the question
(06:34):
what are the FIRMI bubbles? When we're talking about bubbles,
we're not talking about Matt having a soapy bath, or
making Hulaho bubbles, or even the bubble of our atmosphere.
We're talking about something on an enormous scale, something basically
the size of the galaxy that was only recently discovered,
and we talked about recently on a podcast about how
stuff at the center of the galaxy is still a
(06:57):
huge mystery. Like, we know there's a big black hole there.
We have lots of questions about black holes. There's a
bunch of stuff swirling around that black hole, and questions
about how those black holes were made and all sorts
of stuff. It's a big, messy swarm of goop there
in the middle of the galaxy. And even Gwyneth Paltrow
can't give us any insight. Yeah, yeah, well maybe she's
(07:18):
in this Fermi bubbles that we'll see. That's right. And
so today we're gonna be talking about an amazing discovery
that they made recently. They found these huge blobs of
gas they're like basically the size of the galaxy, and
they called them the Fermi bubbles. And before we dig
into talking about what they are and what they mean
and what they might reveal about the nature of our
galaxy and the universe in general. I was wondering had
(07:40):
anybody heard of this? Because in my field and physics,
everybody knows about it because it's a big discovery made
pretty recently. Somebody was recently awarded a big prize for it.
But I wasn't sure if it had sort of penetrated
into the cultural Zeite guys to people who have been
talking about this, and so I walked around campus at
U C Irvine and I asked people, Hey, have you
ever heard of the Fermi bubbles? Do you know what
(08:01):
they are? Before you listen to these answers, think to yourself,
do you know what the Fermi bubbles are? If I
had asked you randomly on the street, what would you
have said. This is actually my favorite part of your podcast,
when we're asked to just quietly listen, think, think about
our own answer. I love it, and I'm never right,
so I love It's a good time. All right, Well,
listen to these answers and hear what people had to say.
(08:23):
Have you ever heard of the Fermi bubbles? No? No, no, no, no,
I have not known. I've heard the name, but I
the definition escapes me. All right, Matt, what did you
think of people's responses. I have to say that I
also had not heard of Fermi bubbles and I wasn't
really aware of them. I know who for Me is
because I was in Chicago, However, I didn't really know
(08:45):
what these were. And it seems like the people on
her mind did not really know much about him either. No,
pretty much nobody had ever heard of them. You hear
some clever guesses, right, people like, oh, I think I
know who for Me is, or you know, maybe there's
some connection to particle physics with the chamber. That was clever,
But basically zero percent of these people had ever heard
of the Fermi bubbles. And God, that blows me away
(09:07):
because we're making these huge discoveries. This is like when
we talked about on the podcast about the hexagon on Saturn.
You know, everybody has heard of Jupiter's red spot, obvious thing,
fascinating mystery, but very few are Almost nobody had heard
of the fact that there's a huge hexagon on the
top of Saturn. Like, people just don't know that there
are these big mysteries out there, these recent discoveries, and
(09:29):
so um I hope at least after today people will
know a little bit about what the formy bubbles are,
why they're such a fascinating discovery. All right, so we'll
dig into what the formy bubbles are, but first let's
take a quick break, okay, Daniel. So now I've got
(09:55):
some questions, right, So what I've done is I've looked
at a picture at Google search where Fernie bubbles. Is
that how you biologists do research or just type stuff
into Google? The world of the answers are pretty much
already out there, so I so I'm looking at these
Fermi bubbles, and what I'm seeing is this really great
picture of our galaxy, the Milky Way galaxy, and I
(10:16):
see two big purple bubbles I guess that are extending
out from the plane perpendicular to the plane of our
hard spinning disk. So I guess I can start with
my first questions, which is what am I looking at? Yeah,
it's amazing you visualize the galaxy. Most people think of
something pretty flat like a disc. It's got these swirling
(10:36):
arms of stars and that's correct, right. But in this
image that we're looking at, and that I hope that
the folks out there have a chance to Google if
they're not currently driving, you see these huge balls, these
big purple balls. And the most important thing for people
to know is these things are basically the same size
of the galaxy. There like twenty five thousand light years
above and below the galaxy. They're basically the biggest feature
(10:59):
of our galaxy, and nobody even knew they existed until
ten years ago. Right, the disc becomes this, uh, this
little belt that are of all the galaxy has, yeah, exactly,
all the planets, all of life, all of the stars
are kind of like the feature around the balls. I
know exactly. It's like we are the side note to
this enormous feature. Right, And for those of you who
(11:20):
don't know, the whole galaxy in the Milky Way galaxy
is about a hundred thousand light years across, So to
have something that's fifty tho light years wide, that's a
pretty big feature, right, that's maybe the dominant thing. Um.
And so there are these two giant blobs and they're
basically circular, also, like they're tight at the at the
center of the galaxy and then they sort of expand
out and then taper off a little bit. So they
(11:42):
look basically like two huge basketballs um one above and
one below. The galaxy touching right there at the center
of the galaxy, or if I tried my belt really tight,
not my waist. Okay, I just got a very disturbing
mental image. Let's let's pack that out. And there's very
(12:02):
beautiful And there's two of them, right, there's the north
one in the south one, and they're about the same size.
Right there, there is there's a lot of symmetry here,
So let's just start with what are they made of?
We don't even know the answer to that question. We
think that maybe they're made of some sort of hot gas,
which in this case basically means protons. Right, Remember that gas.
(12:23):
Most of the gas in the universe is hydrogen, which
is a proton and an electron, but a lot of
it is hot, which means it's I and I, so
the electron has escaped, so basically just protons. So one
idea is maybe it's just a huge number of protons.
And and the thing to know is, like it would
be a huge number of protons. Like if you took
all those protons and like use them to build stars,
(12:43):
which is something our galaxy is good at, you could
make two million stars. Right, This is not a small
amount of gas. So one idea is maybe they're protons.
The other idea is that maybe they're electrons. Right, maybe
they're like really fast moving, zippy electrons. And I think
the thing to understand is is what we're looking at.
What we're seeing, of course, is light. Right, we have
(13:05):
a telescope out in space that can see these things,
so we're seeing photons from these objects. Right. You know,
when we see like stars that are really far away,
we're not seeing the star. We're seeing the life from
that star. So things that we only see things that
give off light. Right, there could be something out there
like a big black rock or a black hole. We
wouldn't see it because it's not giving off any photons.
(13:26):
So how did we just discover this? Then? I know, right,
how did we not see this before? Well, the story
is that, you know, we didn't have a telescope that
could see these things before. People I think imagine that
we've looked out into the universe, that we've basically seen
the whole universe. But that's not true, right, We've looked
at a very tiny fraction of the universe. Just recently,
(13:47):
we had an episode about like how many stars have
we seen in the sky? And we talked about how
the Hubble, which can see really deep into the universe,
has only looked at a tiny patch of the sky.
Most of the sky has not even been examined by Hubble,
and you could look out there and find this crazy,
amazing stuff nobody's ever seen before. There could be huge
surprises there. So I think the lesson is like every
(14:07):
time we turn on a new astronomical device, we see
crazy stuff that we didn't expect because the universe is
filled with crazy stuff and we just got open lots
of new kinds of eyes. And the key is not
that we're it's not that we're not pointing in the
right direction. If that we're not looking with the right
or we're not using all the wavelengths or something, yeah, exactly.
So this this these things are called Fermi bubbles because
(14:29):
they were discovered by the Fermi telescope, which is named
after Enrico Fermy. So it's a bit of a you know,
double misdirection there. People thought Fermi might have discovered these things,
but now the telescope named after him discovered it. So
I think it's cool he sort of gets credit for
stuff he didn't discover, because, like you know, if you
become a famous scientist and then they name something after
(14:50):
you and then that device is used to discover stuff,
you get like secondary credit for it. I think that's
pretty cool. But yeah, that telescope was the first one
that could see these photons. These are very high energy
gam raise like above fifty or a hundred giga electron volts,
and we just didn't have a great space telescope that
could see these things before. And so essentially the first
time they build one of these things, put it in
(15:11):
space and then looked out into the universe with it,
they spotted these things. It was pretty quick, like it
only took a couple of years of data before they
noticed these things. So we just hadn't been looking at
the right energies before. So there are more of them,
Well there's the our galaxy has only these two. Yeah,
there's the one, the north one and the South one.
And there's a lot of really weird things about them.
Like if you look at the picture, you notice there's
(15:32):
like a really strong cut off, Like they're not these
like amorphous blobs. They're not like, you know, sort of
gradually fading out. They're pretty crisp, like the edges are
kind of sharp, right, And that's really interesting because they're
trying to understand, like what are these things made of,
like you were asking, and so either their protons or
their electrons or you know, they could always be something
(15:53):
totally weird and different. But the thing that's happening is
that you know, there's photons out there all over the universe,
is caused a gray background and and and other sort
of soft photons, and then these really high energy particles,
the protons or the electrons in these bubbles. What they
do is they basically give those photons a boost, like
they interact with those photons, and the photons like get
(16:15):
pushed and then they become really high energy gamma rays
and they come to Earth. And that's what we're seeing.
So we're not literally seeing the gas or the photo
or the electrons directly. We're seeing the photons that got
boosted by those high energy particles in these bubbles. So
it's almost like this little chamber that's everything that comes
into its shooting it out or it's a I guess
(16:36):
that's the high energy part of it. Yeah, exactly, it's
like a little accelerator, right, everything that comes in gets
zoomed out and that's what we're seeing. We're seeing that
photons in this region of space are getting pushed, are
getting boosted up to some really high energy. And that's
the mysteries, like what why are these things here, what
are they doing, what's causing it? Where do they come from?
And do we think it's a cloud of gas or
(16:58):
is it like a bubble with a perimeter than a
hollow center. Now that's really interesting things that it seems
to be sort of smooth. It's not like there's an
edge like a bubble right where it. Mostly it's happening
on the edge um And it's also not really much
more intense closer to the center of the galaxy. We
see the same intensity basically all the way across it,
which is really hard to explain physically. Like we'll talk
(17:19):
later about the possible things that could have made these things,
but none of those hypotheses explain what we see because
none of them can generate a bubble that's smooth all
the way through it. It's really weird. I can't believe
you're gonna make me wait for an answer. Okay, Matt,
at least you have to listen to the rest of
the podcast. You're on the podcast, don't tune out? Should
(17:39):
I tell everybody to skip forward ten minutes? Now, let's
not do that. This might be one of these moments, right,
So when these things were first discovered, can actually what
was it like? If it was recent, then what was
it like in the physics community. It was a big surprise,
right because the Fermi telescope was not launched to find
the Fermi bubbles because nobody knew the over there. It's
(18:00):
one of these moments when you build a device to
look for something and you find something totally different, you know.
A famous example is like the cosmic microwave background. These
guys built a radio telescope to do radar testing and
listen to other stuff from the universe, and they found
this weird buzz background that they couldn't explain, and it
turned out to be this amazing discovery cosmic marcroway background.
(18:22):
We got a podcast schedule for that next week, I think.
And this is the kind of thing that happens a lot.
You build a new instrument, you look out in the universe.
Do you expect to see something? You see something totally different.
So this one was designed basically to discover dark matter
I mean, it also has other intentions. But in my community,
we're most interested in the Fermi telescope because it could
see dark matter, and you might wonder, like, how can
(18:43):
you see you dark matter? Right? And the idea is
that dark matter could bounce into other dark matter and annihilate,
and maybe sometimes that would produce photons and you could
see those. So this device, the Fermi telescope, it's basically
it's like a big particle detector in space. You could
see high energy photons. It turns them into electrons and positrons,
(19:04):
splits them and then it can measure their energy. And
so essentially it's like looking out into space with a
very very high energy light. Right. You know, the Hubble,
for example, looks at visible light um, but this looks
at really really high energy photons. Did they think there
would be anything near the center of the galaxy like
this above and you know above and below it, Yeah,
(19:24):
great question. There was another instrument recently called w MAP,
and it's a sort of like a fuzz. They called
it the w MAP haze above and below the center
of the galaxy, and it was more in the radio waves,
and nobody understood what that was either, and so these
guys were interested, like, well, let's look at that, but
let's also they were looking more specifically at the center
of the galaxy to try to understand whether they could
(19:45):
see a signal of dark matter from there. And you know,
when you do that, you've got to understand the day
that you have to say, like, what are we seeing
to make sure we understand what we can see so
then we can look for the thing we're looking for.
It's like, you know, you gotta understand the backgrounds before
you can look for your signal. But they couldn't. They
were like, what is this you know, yeah, yeah, And
it's one of those moments where they're like it's an
(20:05):
obstacle because they wanted to answer this other science question.
But then potentially that obstacle is a whole new avenue
for discovery. And so they released this paper. It was
kind of a bombshell. People were like, what are you
telling me that the galaxy is a totally different shape
than the one we always imagine and always draw, Like
this this huge new structure which basically changes the way
(20:26):
you should think about the shape of the galaxy. Right,
So it was a pretty big deal. Did you find
it annoying because you were really hoping to know about
dark matter, and now all of a sudden, its that
you knew that everyone was going to be focused on
these bubbles. Yeah, why can't we just turn those bubbles
off so we can get back to the dark matter studies?
Somebody get rid of them? Yeah, exactly, No, it's it's um.
(20:46):
It's frustrating in that respect. It does obscure the dark
matter signal a little bit. But it's also fascinating because
every time you see something that you don't understand, something
that you don't expect, it's a clue, right, It's a
clue that tells you where to look for a new answer,
where to find something new, because by definition, if you
didn't expect it, it means there's something either a new
kind of object out there in the universe or something
(21:10):
you knew about doing something weird, right, like, oh, I
didn't know that stars could do that, or I didn't
know black holes could make this kind of feature. So
you're you're guaranteed to learn something new. So presumably this
is going to teach us a lot about black holes, presumably, right,
since near the center of our galaxy and I knew
you were either you were either going to go for
black holes or for aliens, right, because most of your
(21:31):
go to explanations for weird stuff in space. Hey, well
you know aliens is my go to explanation. When we
don't understand something, you would always explain it using intelligent life, right. Um. Yeah,
so let's talk about that. Let's dig into like what
these might be, how we might explain it, what the
various ideas are, and why none of them actually work.
(21:52):
But let's take another break. Why are they the center
of our galaxy? Is that is that important? It's definitely
a clue, right. We think that they must have been
generated by something at the center because they're touching sort
(22:15):
of the disc of the milky way only there at
the center. So they must be related to something crazy
happening at the center of the galaxy. And remember that
the center of our galaxy we have a really big
black hole, and so you might think maybe like it's
a burp, right, maybe the black hole like ate something
really big. And remember when things get sucked into blood, Yeah,
(22:37):
it's a galactic black hole. Belch indi indigestion from the
black hole. Because remember when black holes eat something, things
don't just like trip and fall into the black hole
and they're totally gone. They swirl around the black hole
because they still have anglar momentum. They get torn up
into pieces, and most of it goes in the black hole,
but some of it gets flung out, right, it gets
shot out from the black hole. And so you see
(23:00):
black holes eat something big. Often there's like a big
jet of gas or something that gets admitted. So you
like to think maybe what's remarkable here too, is that
I often think of the sci fi black holes where
you're looking at the black hole and the spaceships circling
and about to fall into it. And I often think
of then, for some reason, black holes as being one sided.
(23:21):
But I guess when I see these two bubbles and
the symmetry here, it really tells me more that the
black hole exists potentially as a disk, I guess, and
it's belching out of both ends. Well, remember, black holes
are not like like Looney Tunes black holes right where
anybody can roll them up and drag them around. They're
spoil this for me, all right, you're a biologist, you're
(23:43):
allowed to have a totally unreliable, No, black hole is
more like a sphere, right, it's a it's not even
really a hole. It's a dense blob of stuff, right,
So it's more like a really black rock, you know.
But you can fall into it from any direction, so
you're right, it's it's um not preferring the north or
the south side of the galaxy. Either way, it's happy
(24:04):
to gobble stuff from either direction. You would expect of
the black hole created some sort of feature, it would
appear in the north and the south. And in fact,
some galaxies do have features, like they have these jets
of material that gets shot out exactly in these directions,
like one north and one south right from the center
of the galaxy. But those look very different. Those are
really colimnated. They're long, they're thin, they're about the same size,
(24:26):
but they don't look anything like this. And most importantly,
they're really intense close to the black hole, and then
they sort of spread out and slowed down, which is
what you'd expect. But these bubbles they don't look like that. Right,
Like we were saying before, they have these crisp edges
and they're smooth, they like look the same on the
very top of the very farthest part from the center
of the galaxy, as they do close to the center
(24:47):
of the galaxy and in the middle, So that seems
like an important clue about how they were made or
what made them. Right, they don't look like they're spewed
out from the center in that way. I mean, it
really seems like I think the image it also invokes
is on huge bubble that's been cinched in the middle,
presumably because of it's the spinning of the Milky Way.
But I guess that would make you think that the
(25:07):
center should be more dense as well. Yeah, yeah, precisely,
that would. You would see a density there from the
from the cinching, right, So, but we don't know what
made it. We don't know. And you know, other galaxies
have jets, but the Milky Way doesn't have jets, right,
it doesn't have these huge jets. It spewed out, so
though maybe it did in the past. Right, we don't
really know what the history of the Milky Way is.
(25:28):
We can't look back in time at it and understand
if it had jets in the past. But this can't
really be explained by the same mechanism that creates those
galactic jets. And then given our perspective on the arm
of the Milky Way. Would we be able to see
if a big bubble was shutting out towards us. Are
you worried in the same way. I don't know if
(25:49):
we're in a bubble or not. When I listened to
the news, they tell me I'm in a bubble, but
I don't know if that is here. You're you're in
a biology bubble. You're a rattlesnake bubble. Um, No, we are.
We're in an arm in the Milky Way. So we're
not in the middle of one of these bubbles. We
are separated from it. So you know, you can take
off your tinfoil hat. You do not need protection. I
just yeah, but we would be able to tell if
(26:10):
it was like so, the bubbles only extend sort of
perpendicular to the plane of the desk of the Milky Way. Yes,
now that we have this FIRMI telescope, we can see
these bubbles. We can see where they are, and we
can see where they aren't. And we are not in
a bubble. And we can also point this telescope but
other galaxies and be like, hold on, if our galaxy
has these bubbles, you know, does every galaxy have bubbles UM,
(26:33):
And we don't know the answer to that question yet
because these bubbles are a little bit tricky to see,
Like first of all, you need this telescope and you
need a bunch of data because the picture you might
see if you Google, that's after like years of data
and background subtraction. It's not this kind of thing you
can see with the naked eye in five seconds of data.
And the and the other galaxies are really far away.
So we've pointed it at in drama and we've looked
(26:56):
for these bubbles, but we just can't tell if they
exist in other galaxies or not. So we just we
don't know the answer to that question. In fact, we
haven't so we haven't seen any of them or No,
there are other galaxies that are much bigger that have
really big black holes and they have jets, and some
of them have like bubble like features, but they're not
the same as these kind of bubbles. They're like lower
(27:16):
energy photons and also they're much much bigger UM. So
we've never seen a galaxy like this one before UM.
But again we don't know if there are other galaxies
out there like this one because we only recently discovered
the ones that are like around the corner, so the
ones that are in another galaxy really far away will
be harder at a spot. So that's you know, for
future astronomers to discover. Now, are future astronomers looking in
(27:39):
one direction or another? Yeah, future astronomers want to look everywhere, right,
because the universe is jammed full of crazy stuff. And
you know, the next person who's trying to answer this question,
are there Fermi bubbles and another galaxy? They're probably gonna
find something else weird and crazy and get distracted and
never answer that question because they're gonna be studying, you know,
the Fermi bicycle or the you know, whatever next crazy
(28:01):
thing they find out. There probably more hexagons, but there
must certainly be scientists now that are looking for these right,
Oh absolutely yeah. Um. They announced this paper and there
was some folks at m I t Um, Tracy Slatcher
and Dunk Dug finkbiner Um at Harvard and other folks
(28:22):
and people have been following up, and people are looking
for these things at other galaxies. Um. And people are
also spending a lot of time having fun coming up
with various ideas to explain it. One of my favorite
is this starburst hypothesis. They think that maybe is your
mouth watering right now? All right, and we're gonna charge
(28:42):
starburst for this plug, right anyways, Uh, the idea is
that maybe ten million years ago, the Milky Way went
through a period of star formation because a bunch of
gas slammed into another bunch of gas. And when gas
creates these collisions, you get these density that you get
these becaus of density, and that's how stars formed. And
(29:03):
maybe when those stars were formed, that kind of event
could have also jetted out a bunch of gas in
either direction. It could have been these big gas outflows
from a big burst of star formation, you know, and
that would have happened like ten million years ago. Hold on,
you said ten million years ago. Ten million years ago,
and remember that's nothing. It's it's like avolution standard that
(29:26):
I know. There were things and people crawling around on
Earth right at the time that this happened. And remember
that there were rattlesnakes biting things. Years ago is recent, yea,
even in biological time scale. And remember the galaxy is
super old. It's almost as old as the universe. It's
thirteen billion years old. So this is a very new feature.
(29:47):
And we also don't know how long it's gonna last.
Maybe it'll dissipate and in a few million years it
will be gone right in our and our could just
be a blip. It could just be a blip, right,
something we tell our grandkids about, you know, when I
was had we had these big bubbles and shut up, grandpa,
or one of many blips. This might be a feature
(30:07):
that's happened for the entire lifestyle life of the galaxy. Yeah,
and um, none of these explanations, like the gas outflows
from star formation or the black hole burps or you
know anything else, none of them explained this really weird
feature that the bubbles are smooth, right, All of those
hypotheses predict something more intense close to the center and
(30:29):
then sort of fading out. So the real answer is
something that nobody's thought of yet. The real answer is
something that some future scientists will discover. And you know,
it could be something really deep, like there's a new
kind of object there and then in the middle of
the black hole or in the middle of the galaxy,
or it could be like you know, very rarely black
holes have indigestion and fared out. These weird bubbles and
(30:51):
you know, we just happened to see one, in which case,
like how weird and lucky that our galaxy did this,
like right now basically, but if these bubbles are smooth,
it makes me it makes it hard to believe that
there is emitting out almost from this black hole. Is
it possible that these bubbles are pulling being pulled into
the galaxy from elsewhere? WHOA, that is such a good idea.
(31:11):
I'm going to write that down and take credit for it. Good.
We expect nothing less. You're so smart. It's like you
got bitten by our radioactive rattlesnake or something. I'm beginning
to feel it now. No, that's a great question. But
then wherever they have come from? Right, Like, maybe if
they're sucking up something um from the outside, then they
(31:32):
have to be a symmetric source, right, you need something
on the north and the south to get to create
these bubbles from outside the galaxy. That seems pretty unlikely
because they're so symmetrically the same size on both side. Sure, yeah,
I don't understand it. I just have to pose the ideas.
You are supposed to explain it, all right, Well, on
(31:54):
our the biology version of this podcast. I'm gonna expect
some answers from you, all right, Well, so this has
been very informative, and I have to say, physics, you're
doing a good job. But I think, you know, these
are kind of amazing. I think it's amazing that we
have these new, i mean really young clouds of gas
that are just essentially stopped at the center of our unit,
(32:15):
our center of our galaxy. The fact that we don't
know what they are, I think it's just fascinating. The
fact that the science behind it is only not even
ten years old is is really fascinating. So it seems
like the kind of thing that we might actually get
some really cool answers for in the near future. Yeah,
twenty years from now, people to look back and they're
going to know the answer, hopefully, and uh, it's gonna
(32:37):
seem obvious to them, right whereas right now we're standing
at the forefront of human ignorance, not knowing where it's
going to lead. But the favorite place to stand, Well,
the my favorite thing about this kind of thing is
that it's a hint, right, It's a hint about how
many more amazing discoveries there are out there. If every
time we open a new kind of eyeball into the universe,
(32:59):
we see some thing crazy and unexpected. That tells you
that there's a lot more crazy stuff out there waiting
to be discovered. And so we should build as many
kinds of scientific eyeballs as we can, especially astronomical ones,
because there's so much out there in the universe waiting
for us to find it and to go. What the
(33:19):
f is that more eyeballs is absolutely what we need,
all right, Get on at physicists, engineers, more telescopes now, yeah,
and I don't mean rattlesnakes with more eyeballs, they have plenty.
What I'm talking about is news scientific instruments. All right.
Thanks everyone for tuning in. That was our podcast about
the mystery of the Fermi bubbles. If you have something
(33:41):
you'd like us to rattle on about ignorantly, then please
send us a suggestion to feedback at Daniel and Jorge
dot com. Or if you have a question about something
random about physics. We answer all of our listener emails.
Send it to questions at Daniel and Jorge dot com.
Thanks Matt for joining us on today's podcast. Thank you,
it's been marvelous al right, So go all right, Mrs Nasal,
(34:07):
go off and solve your rattlesnake venom problem. And we
don't want to hear back from you until it's done.
Will you solve these problems? Sounds good? Thanks everyone for
tuning in. If you still have a question after listening
to all these explanations, please drop us the line. We'd
(34:27):
love to hear from you. You can find us at Facebook, Twitter,
and Instagram at Daniel and Jorge that's one word, or
email us at Feedback at Daniel and Jorge dot com.
Thanks for listening, and remember that Daniel and Jorge explained.
The Universe is a production of I Heart Radio More
podcast from my Heart Radio. Visit the I Heart Radio
Apple podcasts, or wherever you listen to your favorite shows.
(34:56):
Yea
If I told you that today we're talking about bubbles,
what comes to mind? I'm thinking of bathtime. Are you
in the bath as we're recording this. I'm just worried.
I listened to the Higgs boson. I think that rubber
duck ees might destroy the universe. All right, well, I
want you to think bigger than just your bathtube. Okay,
like those hula hoop bubbles that you make with your
(00:30):
kids in this classic bath that's the right direction. But
go bigger, bigger than that. Then you've got to be
talking about like our atmosphere or something as a huge
bubble around the whole ward, even bigger. Can a bubble
be that pig? Can you even think about a bubble
that big? Or is it gonna blow your mind? Hi?
(01:06):
This is Daniel. I'm a particle physicist and the co
author of the book We Have No Idea, A Guide
the Unknown Universe. My other co host and co author
is Jorge cham, a cartoonist and a friend of mine.
Jorge is not here today, so we have a guest host,
Professor Matt Georgianni of the University of Maryland. Say Hi
to everybody. Matt, Hello, everybody. Yeah, I'm Matt Georgiohnny, And
(01:29):
I'm a biologist, so I don't know anything about physics
unless it makes animals. Biology is basically just big physics, though,
isn't it It is? I mean, it's biologist what physicists
which they could study to lay the gauntlet down. Now, Wow,
I thought you were admitting that biology is nothing but
(01:50):
an emergent phenomenon of physics. But now it seems you're
trying to turn the tables on me. It won't be
the first time, So tell everybody a little bit about yourself, Matt.
Why are you a biologist? What do you study? What
do you find fascinating? I loved mathematics early on, in
in high school and in college, but I got really taken.
Loved is in past tense. I loved, I still love,
(02:11):
But I got really taken with evolution. And I loved
how big, you know, animals evolved into different shapes and beings,
and how all of life on Earth came to be.
And I just find it utterly fascinating. You mean the
theory of evolution, right, the theory of evolution, yes, but
what a wonderful theory right up there with the theory
of gravity. Two of my favorite theory. Oh snap, snap,
(02:34):
all right, I will I'll take that blow touchet. So
do you study evolution in your research? I do. I
study rattlesnake venom actually, and how that has evolved across
different types of snakes. Wow? So how many years until
humans evolve venom that we can squirt out of our teeth? Man?
I am keep waiting. Every day I check my teeth
(02:54):
and I haven't done it yet. What do you mean waiting?
If anybody's going to develop that technology, it's going to
be you. We are waiting for you to develop it. Matt. Well,
I'm working on it. I'll get there. Have you tried
getting bitten by a radioactive rattlesnake? I feel like now
this is why I called you. Now I can finally
complete my research. Al Right, Well, I want authorship or
(03:15):
at least acknowledgement on the paper where you announced that.
Give me my first bite? How about that? That's a deal.
That's a deal. All right? Well, welcome you are our
co host today our guest host on the podcast Daniel
and Jorge explain the Universe featuring Today Matt Georgianni. So
I guess it's Daniel and Matt explained Daniel and Jorges
universe or I'm not sure what the temporary name should be,
(03:37):
or maybe I can just work up what you guys explain.
That's right. Daniel tries to explain the universe and Matt
confuses everybody. That's right. And our podcast is a production
of I Heart Radio. Today we're gonna be talking about
all those amazing things that you do go into science
to discover. You went into science to talk to discover
evolution and unravel the secrets of the history of life.
And I went into physics to reveal a deeper truth
(03:59):
about the nature of the universe. And as always when
you jump into something scientific, you never know what you're
going to discover. And today's episode is going to be
all about that, about unexpected discoveries. What's the most interesting
or famous unexpected discovery in biology or in rattlesnake venom.
I can only say that one of the things about
biology is that we as we keep discovering things, we
(04:21):
the conclusion is always that everything is way more complicated
than we ever thought it was. Oh, I see, so
we're like, hey, we evolved from primates. There must be
a straight, dotted line between us and some common ancestor
of chimps, and then we dig up a bunch of
fossils and they don't make a nice dotted line. I
think human evolution is one of these great cases where
we did kind of think maybe there would be a
(04:43):
sort of simple line, and all we keep learning is
that populations of early humans and different hominids were intermingling
and mixing, and that the modern human that we that
what we envision is actually this really complex mixture of
a bunch of different populations of humans and early humans
and we're just way more complex than we ever thought
(05:05):
we were. And do you think that's like a really
fun moment when you're, you know, digging up a skeleton
that doesn't look anything like the one you expected to find,
because that opens the doors to crazy new ideas. Or
do you think it's like frustrating. We're like, look, I
just got to graduate, I want to write this paper,
and now this data doesn't make any sense to me.
I think it it's a little of both. I think
(05:26):
the first time you realize it's not the answer you expected,
you think, oh great, I was really hoping I could
wrap this up, and then your mind starts to click
and you start to think of all the other new
questions you suddenly have, and then all of a sudden,
the world just becomes that much bigger. And that's that's
really a fun moment. Yeah, And I think there's an
analogy there. I think like the progress of science in
(05:46):
general is something like the weird, complicated mess of human evolution.
You know, we make progress in this direction, and we
got to back up and go this other way, and
then we stumble across this thing, and then the end
we draw some conclusions based on this big mess combination
of ideas, this population of discoveries. Yeah. And so today
on the podcast, we'll be talking about an amazing discovery
(06:08):
that was made very recently, within the last ten years, uh,
something which totally changes what we know about the very
galaxy we live in. I love that physics is still
discovering things. You thought physics was used up like a
hundred years ago, But I thought that Einstein and Newton
had figured it all out. No, No, not at all.
So today on the podcast, we'll be answering the question
(06:34):
what are the FIRMI bubbles? When we're talking about bubbles,
we're not talking about Matt having a soapy bath, or
making Hulaho bubbles, or even the bubble of our atmosphere.
We're talking about something on an enormous scale, something basically
the size of the galaxy that was only recently discovered,
and we talked about recently on a podcast about how
stuff at the center of the galaxy is still a
(06:57):
huge mystery. Like, we know there's a big black hole there.
We have lots of questions about black holes. There's a
bunch of stuff swirling around that black hole, and questions
about how those black holes were made and all sorts
of stuff. It's a big, messy swarm of goop there
in the middle of the galaxy. And even Gwyneth Paltrow
can't give us any insight. Yeah, yeah, well maybe she's
(07:18):
in this Fermi bubbles that we'll see. That's right. And
so today we're gonna be talking about an amazing discovery
that they made recently. They found these huge blobs of
gas they're like basically the size of the galaxy, and
they called them the Fermi bubbles. And before we dig
into talking about what they are and what they mean
and what they might reveal about the nature of our
galaxy and the universe in general. I was wondering had
(07:40):
anybody heard of this? Because in my field and physics,
everybody knows about it because it's a big discovery made
pretty recently. Somebody was recently awarded a big prize for it.
But I wasn't sure if it had sort of penetrated
into the cultural Zeite guys to people who have been
talking about this, and so I walked around campus at
U C Irvine and I asked people, Hey, have you
ever heard of the Fermi bubbles? Do you know what
(08:01):
they are? Before you listen to these answers, think to yourself,
do you know what the Fermi bubbles are? If I
had asked you randomly on the street, what would you
have said. This is actually my favorite part of your podcast,
when we're asked to just quietly listen, think, think about
our own answer. I love it, and I'm never right,
so I love It's a good time. All right, Well,
listen to these answers and hear what people had to say.
(08:23):
Have you ever heard of the Fermi bubbles? No? No, no, no, no,
I have not known. I've heard the name, but I
the definition escapes me. All right, Matt, what did you
think of people's responses. I have to say that I
also had not heard of Fermi bubbles and I wasn't
really aware of them. I know who for Me is
because I was in Chicago, However, I didn't really know
(08:45):
what these were. And it seems like the people on
her mind did not really know much about him either. No,
pretty much nobody had ever heard of them. You hear
some clever guesses, right, people like, oh, I think I
know who for Me is, or you know, maybe there's
some connection to particle physics with the chamber. That was clever,
But basically zero percent of these people had ever heard
of the Fermi bubbles. And God, that blows me away
(09:07):
because we're making these huge discoveries. This is like when
we talked about on the podcast about the hexagon on Saturn.
You know, everybody has heard of Jupiter's red spot, obvious thing,
fascinating mystery, but very few are Almost nobody had heard
of the fact that there's a huge hexagon on the
top of Saturn. Like, people just don't know that there
are these big mysteries out there, these recent discoveries, and
(09:29):
so um I hope at least after today people will
know a little bit about what the formy bubbles are,
why they're such a fascinating discovery. All right, so we'll
dig into what the formy bubbles are, but first let's
take a quick break, okay, Daniel. So now I've got
(09:55):
some questions, right, So what I've done is I've looked
at a picture at Google search where Fernie bubbles. Is
that how you biologists do research or just type stuff
into Google? The world of the answers are pretty much
already out there, so I so I'm looking at these
Fermi bubbles, and what I'm seeing is this really great
picture of our galaxy, the Milky Way galaxy, and I
(10:16):
see two big purple bubbles I guess that are extending
out from the plane perpendicular to the plane of our
hard spinning disk. So I guess I can start with
my first questions, which is what am I looking at? Yeah,
it's amazing you visualize the galaxy. Most people think of
something pretty flat like a disc. It's got these swirling
(10:36):
arms of stars and that's correct, right. But in this
image that we're looking at, and that I hope that
the folks out there have a chance to Google if
they're not currently driving, you see these huge balls, these
big purple balls. And the most important thing for people
to know is these things are basically the same size
of the galaxy. There like twenty five thousand light years
above and below the galaxy. They're basically the biggest feature
(10:59):
of our galaxy, and nobody even knew they existed until
ten years ago. Right, the disc becomes this, uh, this
little belt that are of all the galaxy has, yeah, exactly,
all the planets, all of life, all of the stars
are kind of like the feature around the balls. I
know exactly. It's like we are the side note to
this enormous feature. Right, And for those of you who
(11:20):
don't know, the whole galaxy in the Milky Way galaxy
is about a hundred thousand light years across, So to
have something that's fifty tho light years wide, that's a
pretty big feature, right, that's maybe the dominant thing. Um.
And so there are these two giant blobs and they're
basically circular, also, like they're tight at the at the
center of the galaxy and then they sort of expand
out and then taper off a little bit. So they
(11:42):
look basically like two huge basketballs um one above and
one below. The galaxy touching right there at the center
of the galaxy, or if I tried my belt really tight,
not my waist. Okay, I just got a very disturbing
mental image. Let's let's pack that out. And there's very
(12:02):
beautiful And there's two of them, right, there's the north
one in the south one, and they're about the same size.
Right there, there is there's a lot of symmetry here,
So let's just start with what are they made of?
We don't even know the answer to that question. We
think that maybe they're made of some sort of hot gas,
which in this case basically means protons. Right, Remember that gas.
(12:23):
Most of the gas in the universe is hydrogen, which
is a proton and an electron, but a lot of
it is hot, which means it's I and I, so
the electron has escaped, so basically just protons. So one
idea is maybe it's just a huge number of protons.
And and the thing to know is, like it would
be a huge number of protons. Like if you took
all those protons and like use them to build stars,
(12:43):
which is something our galaxy is good at, you could
make two million stars. Right, This is not a small
amount of gas. So one idea is maybe they're protons.
The other idea is that maybe they're electrons. Right, maybe
they're like really fast moving, zippy electrons. And I think
the thing to understand is is what we're looking at.
What we're seeing, of course, is light. Right, we have
(13:05):
a telescope out in space that can see these things,
so we're seeing photons from these objects. Right. You know,
when we see like stars that are really far away,
we're not seeing the star. We're seeing the life from
that star. So things that we only see things that
give off light. Right, there could be something out there
like a big black rock or a black hole. We
wouldn't see it because it's not giving off any photons.
(13:26):
So how did we just discover this? Then? I know, right,
how did we not see this before? Well, the story
is that, you know, we didn't have a telescope that
could see these things before. People I think imagine that
we've looked out into the universe, that we've basically seen
the whole universe. But that's not true, right, We've looked
at a very tiny fraction of the universe. Just recently,
(13:47):
we had an episode about like how many stars have
we seen in the sky? And we talked about how
the Hubble, which can see really deep into the universe,
has only looked at a tiny patch of the sky.
Most of the sky has not even been examined by Hubble,
and you could look out there and find this crazy,
amazing stuff nobody's ever seen before. There could be huge
surprises there. So I think the lesson is like every
(14:07):
time we turn on a new astronomical device, we see
crazy stuff that we didn't expect because the universe is
filled with crazy stuff and we just got open lots
of new kinds of eyes. And the key is not
that we're it's not that we're not pointing in the
right direction. If that we're not looking with the right
or we're not using all the wavelengths or something, yeah, exactly.
So this this these things are called Fermi bubbles because
(14:29):
they were discovered by the Fermi telescope, which is named
after Enrico Fermy. So it's a bit of a you know,
double misdirection there. People thought Fermi might have discovered these things,
but now the telescope named after him discovered it. So
I think it's cool he sort of gets credit for
stuff he didn't discover, because, like you know, if you
become a famous scientist and then they name something after
(14:50):
you and then that device is used to discover stuff,
you get like secondary credit for it. I think that's
pretty cool. But yeah, that telescope was the first one
that could see these photons. These are very high energy
gam raise like above fifty or a hundred giga electron volts,
and we just didn't have a great space telescope that
could see these things before. And so essentially the first
time they build one of these things, put it in
(15:11):
space and then looked out into the universe with it,
they spotted these things. It was pretty quick, like it
only took a couple of years of data before they
noticed these things. So we just hadn't been looking at
the right energies before. So there are more of them,
Well there's the our galaxy has only these two. Yeah,
there's the one, the north one and the South one.
And there's a lot of really weird things about them.
Like if you look at the picture, you notice there's
(15:32):
like a really strong cut off, Like they're not these
like amorphous blobs. They're not like, you know, sort of
gradually fading out. They're pretty crisp, like the edges are
kind of sharp, right, And that's really interesting because they're
trying to understand, like what are these things made of,
like you were asking, and so either their protons or
their electrons or you know, they could always be something
(15:53):
totally weird and different. But the thing that's happening is
that you know, there's photons out there all over the universe,
is caused a gray background and and and other sort
of soft photons, and then these really high energy particles,
the protons or the electrons in these bubbles. What they
do is they basically give those photons a boost, like
they interact with those photons, and the photons like get
(16:15):
pushed and then they become really high energy gamma rays
and they come to Earth. And that's what we're seeing.
So we're not literally seeing the gas or the photo
or the electrons directly. We're seeing the photons that got
boosted by those high energy particles in these bubbles. So
it's almost like this little chamber that's everything that comes
into its shooting it out or it's a I guess
(16:36):
that's the high energy part of it. Yeah, exactly, it's
like a little accelerator, right, everything that comes in gets
zoomed out and that's what we're seeing. We're seeing that
photons in this region of space are getting pushed, are
getting boosted up to some really high energy. And that's
the mysteries, like what why are these things here, what
are they doing, what's causing it? Where do they come from?
And do we think it's a cloud of gas or
(16:58):
is it like a bubble with a perimeter than a
hollow center. Now that's really interesting things that it seems
to be sort of smooth. It's not like there's an
edge like a bubble right where it. Mostly it's happening
on the edge um And it's also not really much
more intense closer to the center of the galaxy. We
see the same intensity basically all the way across it,
which is really hard to explain physically. Like we'll talk
(17:19):
later about the possible things that could have made these things,
but none of those hypotheses explain what we see because
none of them can generate a bubble that's smooth all
the way through it. It's really weird. I can't believe
you're gonna make me wait for an answer. Okay, Matt,
at least you have to listen to the rest of
the podcast. You're on the podcast, don't tune out? Should
(17:39):
I tell everybody to skip forward ten minutes? Now, let's
not do that. This might be one of these moments, right,
So when these things were first discovered, can actually what
was it like? If it was recent, then what was
it like in the physics community. It was a big surprise,
right because the Fermi telescope was not launched to find
the Fermi bubbles because nobody knew the over there. It's
(18:00):
one of these moments when you build a device to
look for something and you find something totally different, you know.
A famous example is like the cosmic microwave background. These
guys built a radio telescope to do radar testing and
listen to other stuff from the universe, and they found
this weird buzz background that they couldn't explain, and it
turned out to be this amazing discovery cosmic marcroway background.
(18:22):
We got a podcast schedule for that next week, I think.
And this is the kind of thing that happens a lot.
You build a new instrument, you look out in the universe.
Do you expect to see something? You see something totally different.
So this one was designed basically to discover dark matter
I mean, it also has other intentions. But in my community,
we're most interested in the Fermi telescope because it could
see dark matter, and you might wonder, like, how can
(18:43):
you see you dark matter? Right? And the idea is
that dark matter could bounce into other dark matter and annihilate,
and maybe sometimes that would produce photons and you could
see those. So this device, the Fermi telescope, it's basically
it's like a big particle detector in space. You could
see high energy photons. It turns them into electrons and positrons,
(19:04):
splits them and then it can measure their energy. And
so essentially it's like looking out into space with a
very very high energy light. Right. You know, the Hubble,
for example, looks at visible light um, but this looks
at really really high energy photons. Did they think there
would be anything near the center of the galaxy like
this above and you know above and below it, Yeah,
(19:24):
great question. There was another instrument recently called w MAP,
and it's a sort of like a fuzz. They called
it the w MAP haze above and below the center
of the galaxy, and it was more in the radio waves,
and nobody understood what that was either, and so these
guys were interested, like, well, let's look at that, but
let's also they were looking more specifically at the center
of the galaxy to try to understand whether they could
(19:45):
see a signal of dark matter from there. And you know,
when you do that, you've got to understand the day
that you have to say, like, what are we seeing
to make sure we understand what we can see so
then we can look for the thing we're looking for.
It's like, you know, you gotta understand the backgrounds before
you can look for your signal. But they couldn't. They
were like, what is this you know, yeah, yeah, And
it's one of those moments where they're like it's an
(20:05):
obstacle because they wanted to answer this other science question.
But then potentially that obstacle is a whole new avenue
for discovery. And so they released this paper. It was
kind of a bombshell. People were like, what are you
telling me that the galaxy is a totally different shape
than the one we always imagine and always draw, Like
this this huge new structure which basically changes the way
(20:26):
you should think about the shape of the galaxy. Right,
So it was a pretty big deal. Did you find
it annoying because you were really hoping to know about
dark matter, and now all of a sudden, its that
you knew that everyone was going to be focused on
these bubbles. Yeah, why can't we just turn those bubbles
off so we can get back to the dark matter studies?
Somebody get rid of them? Yeah, exactly, No, it's it's um.
(20:46):
It's frustrating in that respect. It does obscure the dark
matter signal a little bit. But it's also fascinating because
every time you see something that you don't understand, something
that you don't expect, it's a clue, right, It's a
clue that tells you where to look for a new answer,
where to find something new, because by definition, if you
didn't expect it, it means there's something either a new
kind of object out there in the universe or something
(21:10):
you knew about doing something weird, right, like, oh, I
didn't know that stars could do that, or I didn't
know black holes could make this kind of feature. So
you're you're guaranteed to learn something new. So presumably this
is going to teach us a lot about black holes, presumably, right,
since near the center of our galaxy and I knew
you were either you were either going to go for
black holes or for aliens, right, because most of your
(21:31):
go to explanations for weird stuff in space. Hey, well
you know aliens is my go to explanation. When we
don't understand something, you would always explain it using intelligent life, right. Um. Yeah,
so let's talk about that. Let's dig into like what
these might be, how we might explain it, what the
various ideas are, and why none of them actually work.
(21:52):
But let's take another break. Why are they the center
of our galaxy? Is that is that important? It's definitely
a clue, right. We think that they must have been
generated by something at the center because they're touching sort
(22:15):
of the disc of the milky way only there at
the center. So they must be related to something crazy
happening at the center of the galaxy. And remember that
the center of our galaxy we have a really big
black hole, and so you might think maybe like it's
a burp, right, maybe the black hole like ate something
really big. And remember when things get sucked into blood, Yeah,
(22:37):
it's a galactic black hole. Belch indi indigestion from the
black hole. Because remember when black holes eat something, things
don't just like trip and fall into the black hole
and they're totally gone. They swirl around the black hole
because they still have anglar momentum. They get torn up
into pieces, and most of it goes in the black hole,
but some of it gets flung out, right, it gets
shot out from the black hole. And so you see
(23:00):
black holes eat something big. Often there's like a big
jet of gas or something that gets admitted. So you
like to think maybe what's remarkable here too, is that
I often think of the sci fi black holes where
you're looking at the black hole and the spaceships circling
and about to fall into it. And I often think
of then, for some reason, black holes as being one sided.
(23:21):
But I guess when I see these two bubbles and
the symmetry here, it really tells me more that the
black hole exists potentially as a disk, I guess, and
it's belching out of both ends. Well, remember, black holes
are not like like Looney Tunes black holes right where
anybody can roll them up and drag them around. They're
spoil this for me, all right, you're a biologist, you're
(23:43):
allowed to have a totally unreliable, No, black hole is
more like a sphere, right, it's a it's not even
really a hole. It's a dense blob of stuff, right,
So it's more like a really black rock, you know.
But you can fall into it from any direction, so
you're right, it's it's um not preferring the north or
the south side of the galaxy. Either way, it's happy
(24:04):
to gobble stuff from either direction. You would expect of
the black hole created some sort of feature, it would
appear in the north and the south. And in fact,
some galaxies do have features, like they have these jets
of material that gets shot out exactly in these directions,
like one north and one south right from the center
of the galaxy. But those look very different. Those are
really colimnated. They're long, they're thin, they're about the same size,
(24:26):
but they don't look anything like this. And most importantly,
they're really intense close to the black hole, and then
they sort of spread out and slowed down, which is
what you'd expect. But these bubbles they don't look like that. Right,
Like we were saying before, they have these crisp edges
and they're smooth, they like look the same on the
very top of the very farthest part from the center
of the galaxy, as they do close to the center
(24:47):
of the galaxy and in the middle, So that seems
like an important clue about how they were made or
what made them. Right, they don't look like they're spewed
out from the center in that way. I mean, it
really seems like I think the image it also invokes
is on huge bubble that's been cinched in the middle,
presumably because of it's the spinning of the Milky Way.
But I guess that would make you think that the
(25:07):
center should be more dense as well. Yeah, yeah, precisely,
that would. You would see a density there from the
from the cinching, right, So, but we don't know what
made it. We don't know. And you know, other galaxies
have jets, but the Milky Way doesn't have jets, right,
it doesn't have these huge jets. It spewed out, so
though maybe it did in the past. Right, we don't
really know what the history of the Milky Way is.
(25:28):
We can't look back in time at it and understand
if it had jets in the past. But this can't
really be explained by the same mechanism that creates those
galactic jets. And then given our perspective on the arm
of the Milky Way. Would we be able to see
if a big bubble was shutting out towards us. Are
you worried in the same way. I don't know if
(25:49):
we're in a bubble or not. When I listened to
the news, they tell me I'm in a bubble, but
I don't know if that is here. You're you're in
a biology bubble. You're a rattlesnake bubble. Um, No, we are.
We're in an arm in the Milky Way. So we're
not in the middle of one of these bubbles. We
are separated from it. So you know, you can take
off your tinfoil hat. You do not need protection. I
just yeah, but we would be able to tell if
(26:10):
it was like so, the bubbles only extend sort of
perpendicular to the plane of the desk of the Milky Way. Yes,
now that we have this FIRMI telescope, we can see
these bubbles. We can see where they are, and we
can see where they aren't. And we are not in
a bubble. And we can also point this telescope but
other galaxies and be like, hold on, if our galaxy
has these bubbles, you know, does every galaxy have bubbles UM,
(26:33):
And we don't know the answer to that question yet
because these bubbles are a little bit tricky to see,
Like first of all, you need this telescope and you
need a bunch of data because the picture you might
see if you Google, that's after like years of data
and background subtraction. It's not this kind of thing you
can see with the naked eye in five seconds of data.
And the and the other galaxies are really far away.
So we've pointed it at in drama and we've looked
(26:56):
for these bubbles, but we just can't tell if they
exist in other galaxies or not. So we just we
don't know the answer to that question. In fact, we
haven't so we haven't seen any of them or No,
there are other galaxies that are much bigger that have
really big black holes and they have jets, and some
of them have like bubble like features, but they're not
the same as these kind of bubbles. They're like lower
(27:16):
energy photons and also they're much much bigger UM. So
we've never seen a galaxy like this one before UM.
But again we don't know if there are other galaxies
out there like this one because we only recently discovered
the ones that are like around the corner, so the
ones that are in another galaxy really far away will
be harder at a spot. So that's you know, for
future astronomers to discover. Now, are future astronomers looking in
(27:39):
one direction or another? Yeah, future astronomers want to look everywhere, right,
because the universe is jammed full of crazy stuff. And
you know, the next person who's trying to answer this question,
are there Fermi bubbles and another galaxy? They're probably gonna
find something else weird and crazy and get distracted and
never answer that question because they're gonna be studying, you know,
the Fermi bicycle or the you know, whatever next crazy
(28:01):
thing they find out. There probably more hexagons, but there
must certainly be scientists now that are looking for these right,
Oh absolutely yeah. Um. They announced this paper and there
was some folks at m I t Um, Tracy Slatcher
and Dunk Dug finkbiner Um at Harvard and other folks
(28:22):
and people have been following up, and people are looking
for these things at other galaxies. Um. And people are
also spending a lot of time having fun coming up
with various ideas to explain it. One of my favorite
is this starburst hypothesis. They think that maybe is your
mouth watering right now? All right, and we're gonna charge
(28:42):
starburst for this plug, right anyways, Uh, the idea is
that maybe ten million years ago, the Milky Way went
through a period of star formation because a bunch of
gas slammed into another bunch of gas. And when gas
creates these collisions, you get these density that you get
these becaus of density, and that's how stars formed. And
(29:03):
maybe when those stars were formed, that kind of event
could have also jetted out a bunch of gas in
either direction. It could have been these big gas outflows
from a big burst of star formation, you know, and
that would have happened like ten million years ago. Hold on,
you said ten million years ago. Ten million years ago,
and remember that's nothing. It's it's like avolution standard that
(29:26):
I know. There were things and people crawling around on
Earth right at the time that this happened. And remember
that there were rattlesnakes biting things. Years ago is recent, yea,
even in biological time scale. And remember the galaxy is
super old. It's almost as old as the universe. It's
thirteen billion years old. So this is a very new feature.
(29:47):
And we also don't know how long it's gonna last.
Maybe it'll dissipate and in a few million years it
will be gone right in our and our could just
be a blip. It could just be a blip, right,
something we tell our grandkids about, you know, when I
was had we had these big bubbles and shut up, grandpa,
or one of many blips. This might be a feature
(30:07):
that's happened for the entire lifestyle life of the galaxy. Yeah,
and um, none of these explanations, like the gas outflows
from star formation or the black hole burps or you
know anything else, none of them explained this really weird
feature that the bubbles are smooth, right, All of those
hypotheses predict something more intense close to the center and
(30:29):
then sort of fading out. So the real answer is
something that nobody's thought of yet. The real answer is
something that some future scientists will discover. And you know,
it could be something really deep, like there's a new
kind of object there and then in the middle of
the black hole or in the middle of the galaxy,
or it could be like you know, very rarely black
holes have indigestion and fared out. These weird bubbles and
(30:51):
you know, we just happened to see one, in which case,
like how weird and lucky that our galaxy did this,
like right now basically, but if these bubbles are smooth,
it makes me it makes it hard to believe that
there is emitting out almost from this black hole. Is
it possible that these bubbles are pulling being pulled into
the galaxy from elsewhere? WHOA, that is such a good idea.
(31:11):
I'm going to write that down and take credit for it. Good.
We expect nothing less. You're so smart. It's like you
got bitten by our radioactive rattlesnake or something. I'm beginning
to feel it now. No, that's a great question. But
then wherever they have come from? Right, Like, maybe if
they're sucking up something um from the outside, then they
(31:32):
have to be a symmetric source, right, you need something
on the north and the south to get to create
these bubbles from outside the galaxy. That seems pretty unlikely
because they're so symmetrically the same size on both side. Sure, yeah,
I don't understand it. I just have to pose the ideas.
You are supposed to explain it, all right, Well, on
(31:54):
our the biology version of this podcast. I'm gonna expect
some answers from you, all right, Well, so this has
been very informative, and I have to say, physics, you're
doing a good job. But I think, you know, these
are kind of amazing. I think it's amazing that we
have these new, i mean really young clouds of gas
that are just essentially stopped at the center of our unit,
(32:15):
our center of our galaxy. The fact that we don't
know what they are, I think it's just fascinating. The
fact that the science behind it is only not even
ten years old is is really fascinating. So it seems
like the kind of thing that we might actually get
some really cool answers for in the near future. Yeah,
twenty years from now, people to look back and they're
going to know the answer, hopefully, and uh, it's gonna
(32:37):
seem obvious to them, right whereas right now we're standing
at the forefront of human ignorance, not knowing where it's
going to lead. But the favorite place to stand, Well,
the my favorite thing about this kind of thing is
that it's a hint, right, It's a hint about how
many more amazing discoveries there are out there. If every
time we open a new kind of eyeball into the universe,
(32:59):
we see some thing crazy and unexpected. That tells you
that there's a lot more crazy stuff out there waiting
to be discovered. And so we should build as many
kinds of scientific eyeballs as we can, especially astronomical ones,
because there's so much out there in the universe waiting
for us to find it and to go. What the
(33:19):
f is that more eyeballs is absolutely what we need,
all right, Get on at physicists, engineers, more telescopes now, yeah,
and I don't mean rattlesnakes with more eyeballs, they have plenty.
What I'm talking about is news scientific instruments. All right.
Thanks everyone for tuning in. That was our podcast about
the mystery of the Fermi bubbles. If you have something
(33:41):
you'd like us to rattle on about ignorantly, then please
send us a suggestion to feedback at Daniel and Jorge
dot com. Or if you have a question about something
random about physics. We answer all of our listener emails.
Send it to questions at Daniel and Jorge dot com.
Thanks Matt for joining us on today's podcast. Thank you,
it's been marvelous al right, So go all right, Mrs Nasal,
(34:07):
go off and solve your rattlesnake venom problem. And we
don't want to hear back from you until it's done.
Will you solve these problems? Sounds good? Thanks everyone for
tuning in. If you still have a question after listening
to all these explanations, please drop us the line. We'd
(34:27):
love to hear from you. You can find us at Facebook, Twitter,
and Instagram at Daniel and Jorge that's one word, or
email us at Feedback at Daniel and Jorge dot com.
Thanks for listening, and remember that Daniel and Jorge explained.
The Universe is a production of I Heart Radio More
podcast from my Heart Radio. Visit the I Heart Radio
Apple podcasts, or wherever you listen to your favorite shows.
(34:56):
Yea
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Daniel Whiteson
Kelly Weinersmith
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