What is the Space Roar?

Daniel and Jorge talk about the mysterious, unexplained "space roar" and whether its a clue about something new in the Universe.

Learn more about your ad-choices at https://www.iheartpodcastnetwork.com

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:08):
Hey, Daniel, do you ever think we should explore the
universe with all five senses? Well, I'm definitely a fan
of looking out into space. Yeah, but we have other senses.
Have you thought about what space smells like? Well, astronauts
report that space smells a little bit like a barbecue.
Really does it taste like barbecue? Also, I don't know,

(00:28):
maybe frozen barbecue, I guess. Well, I hope it doesn't
feel like barbecue. Space is not that saucy it turns
out or sound like barbecue. That would just be the
sound of aliens preparing their barbecue grills. Well, I just
hope we're not on the menu. Talk about first contact first,
of course, of course I am more handmade cartoonists and

(01:04):
the creator of PhD comics. Hi, I'm Daniel. I'm a
particle physicist, and I do love me a barbecue. So
it really smells like barbecue space? It does. Actually, we
had to listener question recently about what space smells like.
And they're a bunch of really interesting organic molecules out
there in space that like cling to space suits and
then release themselves when you come back inside, And they

(01:25):
smell like sometimes like sulfur, sometimes like barbecue. What does
it mean? Like the astronauts would go out into space
on a spacewalk and then when they come in they
smell like barbecue. Yeah, exactly, when they open up their
helmets again after they've come back in, the stuff that's
stuck to their space suit now goes up their nostrils
and it smells a little bit like barbecue. Guess technically
barbecues are part of the universe. So yeah, the universe

(01:47):
does smell like barbecue, as it does smell like other things.
Our barbecue universe. Welcome to our podcast Daniel and Jorge
Explain the Universe, a perlection of I Heart Radio in
which we use all sorts of absurd food analogy used
to explain to you what the universe is like. Is
it goopy and saucy? Is it chewy and stringy? Can
you bite right through it? But really, we want to

(02:08):
make sure that you understand the nature of the universe,
the things that scientists are thinking about, the things that
we are mentally chewing on, and the things we have
not yet been able to digest. That's right because even
analogies are part of the universe, and so it's a
broad topic that we are discussing here Daniel and Jorge
explain bad analogies with other worse analogies. Yeah, it feels

(02:32):
like we just be compounding the problem there. But it
is a pretty interesting universe out there, and there's a
lot going on. Like if you just sit there in
space and you float, you can smell things, you can
feel things, I'm sure radiation hitting you, and you can
see definitely a lot out there in the universe. Absolutely,
and we are continuing to invent new ways to interrict

(02:52):
with our universe. And basically every time we do, we
find something shocking, we discover something else out there the
universe we didn't even know existed. Yeah, I mean, we're
just sitting here in one corner of the Milky Way,
which is sitting in one corner of the observable universe,
and we're getting a lot of signals from everywhere. Basically,
anything that gives up light, we get that light, and

(03:13):
we detected with our telescopes and our antennants. Exactly we
are drowning and information from the universe, much of which
we didn't even know existed until recently. For example, most
of astronomy has been done using visible light. Light that
you can see with your eyes and even maybe enhanced
with telescopes, but there are really interesting signals in X

(03:33):
rays and on the other side of the spectrum down
to radio waves, you can also look at all the
particles that are washing over us, neutrinos and other crazy
sources of information about what's going out there in the universe.
And recently we added gravitational waves to our toolkit for
listening to the universe. And each of these tells us
something different about the nature of the universe because different

(03:55):
stuff out there emits in different ways. Some of it
gives off light, some radio waves, some gravitational waves. Each
one can tell us something different about what's out there
in the universe. What sense would you use, Daniel to
describe detecting gravitational waves, Like, what what sense do you
need to detect gravity? Do you feel it? Do we
hear it, do we see it? You would feel it

(04:16):
technically because it's a space quake, right, It's like a
shaking of space itself. Space contracts, it expands into wiggles,
So that's really what's happening. And a lot of science
communication about gravitational waves, though they talk about listening to
the universe they talk about like the chirp of black holes.
I think that's a tiny bit confusing because we're not

(04:38):
using our ears to hear these things. We're not getting
sound waves from gravitational waves. What they've done is taken
the frequency of those waves, transform them into sound waves,
and then listen to them. We're feeling the gravitational waves. Yeah.
I like thinking about gravitational waves as the shaking of space.
All right, Well, there are a lot of things out

(04:58):
there giving of a light and signals and gravity, and
for the most part we sort of know where it's
coming from over or what's making these signals. But sometimes
there are surprises. There are almost always surprises, and a
lot of times these things are picked up by accident.
Somebody develops a new kind of antenna or a new
kind of telescope and looks out of the universe the

(05:18):
first time, maybe looking for one thing and finding something
totally different, and then puzzling over and wondering like, huh,
what's making all that light or emitting all that radiation?
And those are fascinating clues that tell us about something
new out there in the universe, or something we knew
about that's doing something we didn't know about. Yeah, and
there is one particular signal out there that is basically

(05:40):
all around us. You can hear it in every direction,
but we don't know what's making it. It's sort of
this weird, unexplained phenomenon exactly, and it's also got a
hilarious name to it. Oh does it in physics? How surprising?
I'm shocked, hilarious and some ways misleading? Well do they?
On the podcast will be tackling the question what is

(06:07):
the space roar now, Daniel? Is it like a roar
like a lines war or is it more like a
cat's meo like rare like is the universe caddie or
is it you know, not had its morning coffee yet?
What is the universe's attitude exactly? Does the universe need
to go to therapy? Like, dude, chill out, somebody give
the universe some valium? What's definitely cool and chill We've

(06:30):
I think we've established that. Does it got kind of
hot sometimes? Yeah? Exactly. Roar is a pretty funny name. Really.
I would have called this the space hiss, the space
his his yeah, exactly, like the space buzzes. Yeah, the
space buzz That would have been a great name for it,
the space hum um. That makes it sound like alien music,

(06:51):
you know, like Gregorian alien chance, the space whistle while
you work. Yeah, exactly. I think all of those would
have been more accurate name than the space raw. Now
I see now you're calling it. I would spell that
differently than r O A r oh. Yeah, that's more
like the space meal. Yeah. But anyways, it is a thing,

(07:12):
the space roar, and it's kind of a big mystery
in physics, and we were wondering how many people out
there knew what it was or had heard of it
or been I don't know the subject of its attitude.
So thanks to everybody who's willing to guess at the
true nature of something poorly named by astronomers. If you
were willing to participate for a future episode, please write

(07:34):
to me. Two questions at Daniel and Jorge dot com.
I like how you just totally through astronomers under the
bus there. You could have said physicists. You definitely specifically
said astronomers there. Yeah. Well, I feel like they are
the target of your criticism more often than other kind
of physics. Mr particle man, are you serious? Yeah? We

(07:55):
got strange names. We got charming names. But you know,
astronomer is there. Maybe let's call them more creative with
their names. Remember that whole episode about space centaurs. Let's
not hear me raw about this topic any longer. Alright,
let's not hiss about it all right? Well, as usual,
Daniel went out there and ask people what they thought
the space roar was. To think about it for a second.

(08:17):
If someone ask you, what would you say? How would
you answer? Here's what people had to say, saying, as
it's called aurora, I imagine Scott to do with sound waves,
and I think they might come from all directions in space.
The space roar sort of reminds me of a tiger
or Allian. But in our universe, I think that the

(08:38):
space roar could be like an explosion. Maybe it could
be compared to the Big Bang, and maybe this explosion
was the beginning of something. I don't know if it
could have been the beginning of a galaxy. The spice role,
I'm fairly certain is aliens. Probably it can only be

(08:58):
radio waves since nobody can scream with us, who wouldn't
hear it? Because you avoids, the sound cannot travel, So
the space road can be in radio We always talk
about light and energy being transmitted through space, but a
lot of what happens in the universe also produces or
could produce sound if there was something to convey that sound.

(09:22):
So is this some sort of accumulation of that? I
have no idea, all right, I like this idea of
a space tiger or a space lion when alien space tiger? Yeah,
that was basically your answer. Yeah, and some people assume
it has something to do with radio waves or at
least some sort of waves that we're getting out there
from the universe. Yeah, totally solid response there. Yeah, but

(09:45):
technically can you get sound from space? I know in
space no one can hear you scream. But is that
because you're wearing a helmet or because you can't transmit sound? Right,
Anything where you describe something we get from space in
terms of a sound is usually playing the same trick
we talked about with respect to gravitational waves, where you're
getting some other kind of wave and all waves have

(10:06):
a frequency, and then you transform that wave into a
sound wave so you can listen to it. This is
no different than like taking radio waves or X rays
from space which you can't see visually, and then just
shifting them in the spectrum so that you can see
them like a false color image. So no, you can't
actually hear any sounds from space because sounds are mechanical waves.

(10:30):
They require like air shifting or something banging into something else.
So we can't hear anything technically from space, right. But
space isn't completely empty, is right. It's not a perfect vacuum.
There's a little bit of gas and hydrogen everywhere, isn't there? No, exactly,
there are some particles out there, and so you can
imagine there are some like waves in the solar wind,

(10:51):
for example, oscillations that happened, like the sun has a
period of eleven years, where like there's lots of ups
and downs in the radiation it emits. So you can
imagine waves propagating in that medium, and perhaps you can
imagine actually listening to them. So yeah, there are ways
you're right for sound to propagate through not totally empty space.
But space is also not empty in another way. We

(11:13):
always talk about space being filled with quantum fields, and
those fields can propagate waves, and for example, that's what
a photon is. It's a wave in the electromagnetic field
in otherwise empty space m sounds good, so they can
hear you scream in space from radiation burning. Probably if
you scream in light, then yes, people can hear you scream.

(11:35):
All right, So there's this big mystery in physics called
the space roar. Now, Daniel step us through this. What
is the space war? The space roar is a totally weird,
unexplained source of radio from space, And that's why they
call it the space roar because it comes in the
radio spectrum, which is a spectrum where we often listen to. Right,

(11:56):
you might even be hearing this podcast on the radio,
which means it's and transmitted using radio waves. So because
we associate radio waves with sound often, I think that's
why I got this name, the space roar. But basically
it's unexplained source of radio waves from space, I guess,
meaning that if you turn on your radio, you would
technically be able to listen to this roar, right, yeah, exactly,

(12:19):
it is coming in through the radio waves. You need
a radio antenna. And remember that radio waves are just
another part of the electromagnetic spectrum. All of these are photons.
You could call all of it light if you want,
but they're all just part of the same wiggling of
electromagnetic fields. In the center of the spectrum, there's visible light.
Above that there's UV light, and then X rays. Below it,

(12:42):
there's infrared light, and below that are radio waves. So
radio waves are just photons with a very very long wavelength.
And you know, as we were saying earlier, for centuries,
people were doing astronomy only by looking at visible light,
the light you could see with your eyes, and of
course there's a lot of fascinating information about stars and
the universe you can see you just with your eyes
or gathering more of those visible moutons into a telescope.

(13:05):
But in the ninet thirties it was this amazing discovery
that you could actually listen to the sky using radio
waves also, and that there was a huge source of
radio waves coming to us from space. How did we
discover that it wasn't through like actual radios. No, it
was a really interesting accidental discovery by this guy Jansky.
He was hired by the Bell Telephone Company. They wanted

(13:27):
to beam radio signals across the Atlantic, and they were
worried that thunderstorms would generate radio interference, so they hired
him to like listen to the radio spectrum carefully and
see if you could understand these forms of interference. So
he built basically a huge radio telescope, the first radio telescope,
just to gather radio waves, and he heard a lot
of stuff that he couldn't explain as coming from Earth. Interesting,

(13:51):
totally unintended, totally unintended. It was like a fascinating little
piece of science. He heard this weird hiss he couldn't explain,
and actually he discovered that it was related with the
rotation of the Earth, which is how he knew it
wasn't coming from the Earth. It's like seeing something in
the sky. You see it once a day, so you
know that, like as the Earth is turning, it's appearing
in the sky. But he was looking at the sky

(14:13):
in a different spectrum, right, He was looking at the
sky in the radio waves, and what he was actually
listening to was radio emissions from the center of the galaxy.
And so here was like a whole new way to
listen to this guy to look out at the universe.
Nobody ever thought that there are natural sources of radio
waves out there in the universe, and by listening to

(14:34):
them we could tell what's going on. And the whole
field is hilarious sort of because nobody really did anything
about it until at ten years later, when this guy
outside Chicago built the world's first radio telescope by himself
in his backyard, and he was basically the only radio
astronomer in the world for about ten years. A pioneer,

(14:55):
A pioneer absolutely in his backyard. This thing is huge.
It's one of these big dishes. So Jansky's first one
was just like a string of antennas on a big
wheel that he could turn and then whever. He built
the first dish to sort of like concentrate radio waves
and collect them together. And that's the sort of radio
dish that we have now. Like Arisibo until recently was

(15:15):
a big radio telescope, and we have other big radio telescopes.
You can see them. They are these huge dishes, and
they have to be big because radio has very long wavelengths, right.
I guess it's sort of like you know, maybe astronomers
at the time we're still busy trying to figure out
what they were seeing in the visible light spectrum, and
so nobody thought to look in other wavelengths. Yeah, exactly.
There's still plenty of astronomy to do invisible lights. People

(15:38):
are still doing it now, but you know, there's a
lot of spectra out there, and the universe looks different
at different spectrum. You know, different things glow at different temperatures.
Some things are very bright in the UV and very
dark in the visible light, or they're very strong radio
emitters and they're very quiet and invisible, and so it's
sort of like looking at the universe in color instead
of in black and white. You can see different things

(16:00):
light up in different things being dark at different frequencies,
and so it's sort of like extra colors to the universe.
It's really a great way to sort of understand what's
out there, right right. It's a great romantic line. And
hear you're glowing in the X rayspector, all right, So
that was a bit his that he heard back then.
But now we're hearing a roar and it's sort of

(16:21):
unexplained to what's the history of this roar when we
first started listening to it or seeing and who did it.
So there's an experiment developed called the arcade instrument. Arcade
is one of these tortured acronyms that stands for absolute
radiometerr for cosmology, astrophysics, and diffuse emission. But it's basically
a really sensitive radio antenna attached to a balloon and

(16:43):
it goes up into the atmosphere and it listens to
radio waves. And they're trying to really accurately measure these
sources of radio waves because they want to understand things
like the very early universe. They want to listen to
the cosmic background radiation and detect to see if, like
the first stars in the univer gave it a little
bit of hot spots here and there. So they launched
this probe something like ten fifteen years ago, and it

(17:06):
was one of the most sensitive probes to radio waves,
and they heard this crazy hiss that they couldn't explain. Wow,
where did they launch it? Was this one of these
like antarctic balloons or was it outside Chicago, also the
epicenter of radio astronomy. It was launched from a spot
in Texas. NASA has a scientific balloon facility there, and
this thing is not just like a normal balloon. It's

(17:27):
one of these like massive weather balloons, and as it
goes up it gets really really big. And this thing
went up to thirty seven kilometers above the Earth's surface.
All right, So then they send out this balloon and
they I guess we're able to point it. Can they
pointed around, and that's when they heard this roar. They
can't point it. It just sort of like floats around.
They don't steer it. But it has a bunch of

(17:49):
antennas on it, so you can get directional information about
the signals you're picking up based on like when they
arrive at the instruments. It's sort of like parallax or
like binocular vision, and so they and tell where things
are coming from. And so you know, they saw a
lot of the expected stuff in the radio. You can
see the Sun, you can see the galactic center, you
can see Jupiter, you can see other galaxies that are

(18:12):
putting out radio waves, and that's sort of what they expected.
But they also found this sort of like overall signal,
this uniform HIS that nobody had ever heard before, and
it's much much stronger than anything they expected. Interesting. All right,
let's getting too a little bit more in detail of
this his, and then let's talk about where it could

(18:32):
be com firm and what it could be. But first
let's take a quick break. All right, we're talking about
the space roar, a mysterious signal that the arcade instrument

(18:54):
detected on a balloon kilometers up in the sky. Now, Daniel,
this is different than the cosmic microwave background radiation, right,
the CMB r F. That's right, This is different from
the CMB. No are we're not living in the marvel universe.
The CNB does emit in the radio. Right. Part of
the CMB is in the radio spectrum. It's a bit

(19:16):
of confusing terminology here because sometimes waves in this part
of the spectrum are called radio sometimes they're called microwaves.
Through the same thing. Essentially, anything longer than a millimeter
you could call a radio wave, or you could call
it a microwave. So you could also call it the
cosmic radio background m So it is sort of like
the cosmic microwave background, but it's just at a different wavelength. Yeah, exactly.

(19:39):
They were looking for at the slightly longer wavelength portion
that's not as well studied. Because what they wanted to
understand was can they see like the heat the light
put out from some of the first stars in the universe,
which would have emitted in the radio. That was sort
of their scientific goals, like measure this part of the
spectrum really really accurately, and then study it for hints

(20:00):
about the formations of the first stars, which they hoped
would leave a little fingerprint on this part of the universe. Oh,
I see. They sent that Bluna up to study the
CMB specifically, but in the radio wave wavelength, Yeah, exactly,
and to study sort of the longer tails of the CNB,
which people haven't studied as precisely using like Kobe and
Plunk and w MAP and those other satellites. So it

(20:22):
has a slightly different sensitivity than other instruments. So sort
of the first time people looked with this precision at
this part of the spectrum. All right, So then I
guess they expected to hear like a background his but
what they found was not quite what they were expecting
to find. Yeah, they expected to find the CMB, as
we talked about, that's part of the spectrum. They also

(20:43):
expected to hear sort of like a diffuse background, you know,
like all the galaxies that are out there they admit
in the radio, especially if they have a strong black
hole at their center, they're gonna be giving off a
lot of radio waves, So you expect sort of just
like a diffuse source of noise out there in the
universe in radio waves. But they heard this hiss. That's
not The CMB comes at a different wavelength, and it's

(21:05):
much much stronger than what you would expect just from
like all the galaxies emitting. It's like six times larger
than what we can explain. Wait, why can it be
the CMB. Well, we know the CMB pretty well. The
CMB is what you expect from like a two point
seven degree kelvin black body emitter, So we know it's
spectrum and we know it's intensity. And this is just

(21:26):
much bigger than the CMBs. That's not consistent with what
you would expect from the CMB, I see, And it's
much bigger than what you would expect from just a
general like din of the universe, like the general radio
wave background of the universe. Yeah, exactly. And it's the
most sensitive instrument in this area. And it also has
an absolute calibration, which is the reason we first heard it.

(21:48):
Most of the radio balloons and other things listening to
this part of the spectrum before would always just do
a relative calibration that would like listen to two points
and look, for example, at radio from the center of
the galaxy relative to just sort of like an average direction.
So previous experiments couldn't detect like an overall background noise
because they were always like measuring relative to the background noise.

(22:09):
This is the first experiment that can actually measure the
background noise itself because it has an absolute calibration on it.
And so this is the first time we realized that
the background noise that Din you were talking about is
just much larger than what we can explain. You know,
It's like if you walked into a room expecting there
to be ten people in there, but instead there's the
noise from sixty people. You're like, where's all this noise

(22:30):
coming from? Mysterious Yes, something out there in the universe,
like this one. They calibrated by I guess shielding it
completely or just having like knowing their instruments so much
that they know what no radio emissions would sound like
this thing they shielded. They cool it down to two
point seven degrees kelvin using super fluid liquid helium, which

(22:54):
is pretty awesome, and then they also have a device
on there which gives out a known signal, so like
it has its own little calibrator on it, which they
can calibrate absolutely, like they know what they should be
hearing from this, So rather than just using the sky
to calibrate where you're sensitive to background noise in the sky,
they have their own little calibration source. This is like
a little add on thing they did to make it

(23:15):
more sensitive so they could like calibrate it more precisely.
And what they discovered is like, oops, the background from
the sky was much bigger than what everybody had thought,
and nobody had been sensitive to it before because nobody
else had done their own calibration. I see now, is
this coming from a particular direction or it's like it's
coming from everywhere. It seems to be coming from everywhere, right,

(23:35):
It's really weird. It comes from all directions and we
don't know yet, like is it coming from our galaxy
or is it coming from other galaxies. It's really confusing.
If it was coming from other galaxies, to be pretty surprising,
wouldn't it, because they're so far away that that signal
should be pretty weak by the time it gets here,
So it would be a pretty big source at those galaxies.

(23:57):
It would be you know, some of those galaxies really
pump out radio waves all galaxies put out radio for example,
like Andromeda, it puts out ten to the thirty two watts.
Like that's just a huge number. It's hard to wrap
your mind around. You know, your light bulb was like
fifty watts or a hundred wats. Andromeda puts out ten
to the thirty two watts, you know, and it's all noise.

(24:19):
It's not even like playing good music or anything. But
that's actually a fairly quiet galaxy. Some of the galaxies
out there, like Signus A, it puts out a million
times as much radio energy. So these galaxies, you're right,
they're really far away, they're millions of light years away,
but they're still very loud in the radio, which just
tells you how intense they are. Could those be the

(24:41):
source of this space war? Are well, that was the
first ideas that people thought, Oh, well, you know, maybe
the galaxies are louder than we thought, but we can
listen to the individual galaxies. We can tell basically how
loud galaxies are. In order to explain it with galaxies,
you need to just like add more galaxies because you
need this like diffuse emission not just from individual galaxies,

(25:02):
but there sort of isn't enough space to add more galaxies.
Like if you just said, what if there are a
bunch of galaxies out there we didn't know about somehow,
then you'd have to like pack them into the universe
like sardines. And so you can't really explain this just
by like adding more galaxies. M So it can't be galaxies.
Could it be something specific, like you know that just

(25:22):
happens to be like a like a pulsar aimed at
us or something like that, or a quasar. It's coming
from all directions, right, So what you need is like
a very large population of something, all of which is
emitting these sources and emitting sort of like noise to write,
like not any frequencies in specific. Yeah, well down here
in the radio. But exactly, it's not like a spike.

(25:42):
It's not like a very narrow peak. And you know,
and maybe we should talk about like why things emit
radio because that helps us understand what it is that's
generating this sound. All right, Yeah, what makes things emit
radio waves? Well, we have a few sort of categories
of things that can make radio waves. One is just
things being hot. You know, everything in the universe gives
off radiation. It's called black body radiation depending on your temperature,

(26:05):
and things that are really hot give off higher frequency radiation,
you know, for example, like X rays and ultra violet
light from really really hot things. Things like the sun
give off in the visible spectrum. Things like cool clouds
of gas and dust give off in the infrared. But
things also emit in the radio. So like big dark
dust clouds out there in space that are really pretty cold,

(26:27):
they glow in the radio spectrum. That's one source of
radio waves. Another source comes from just like magnetic fields,
charge particles. When they move to a magnetic field, they
get bent, like for example, when the solar wind hits
the Earth's magnetic field, you get the Northern lights. Right.
The particles are emitting light when they bend, because anything

(26:48):
that accelerates, anything that turns in a magnetic field has
to give off a photon to do that, and if
things have the right speed, then those photons are radio waves.
And so if you have charged particles moving through a
magnetic field, you're gonna get photons, and sometimes those photons
are radio waves. But maybe my favorite stories of radio
waves is that it turns out that there are sort

(27:09):
of natural molecular lasers out there in space, natural molecular lasers, yeah, exactly.
You know, a laser works when you have light passing
through a resonant cavity as material in it that can
sort of amplify it. And we don't want to go
in detail into the physics of lasers, but there are
sometimes out there in space these dense pockets of molecular clouds,
and if life passes through them at the right frequency,

(27:32):
it can become a mazer, which is basically a laser,
but in the microwave spectrum. And remember microwaves and radio
waves basically the same thing. And so sometimes out that
there are these basically radio lasers just sort of naturally occurring. Wow,
so there could those be what's causing these space war No,
we don't think those things happen often enough to explain
the space roar, and there wouldn't be coming in every direction.

(27:54):
Those things typically come from like dense clouds inside our
Milky Way. But these emissions don't would follow the pattern
of the Milky Way, right, Like, they don't lie along
the plane of the Milky Way. Remember, the Milky Way
is a flat disk, and so if these things were
coming from our galaxy from something in our galaxy. You
would expect it to be like in the disk of

(28:15):
the galaxy, and that when you pointed your intent is
away from the galaxy, it would get fainter, but it doesn't.
It seems to be in every direction. So either the
Milky Way has some like new structure in it that
tends to be like a spherical halo around us that's
meeting this, or it's coming from somewhere outside the galaxy.
Like it doesn't seem to get louder when you sort

(28:37):
of listen towards the center of the galaxy. It's like
pretty even all around this. It's pretty even in every direction.
And that's why they call it this space roar, because
it's just like filling space with this sound right right.
Trying to make a statement, but to me, it's really
exciting because it's like a puzzle. It's like something out
there is giving off this radiation and we don't have

(28:59):
an explanation for it, and that tells us that it
has to be something new, and we're about to learn
something new about the universe. Something in the universe has
been screaming at us forever and we only recently heard it.
And so that to me is exciting because it makes
us be creative about what could possibly be out there.
Is it's something we're familiar with that screaming in a
way we didn't expect, Or is it something totally new

(29:22):
out there that's creating this crazy radiation? Right? And I
guess they're pretty sure it's not a technical issue, right, Like,
they've calibrated this pretty good. They have calibrated this pretty good. Exactly.
They were really surprised to see this, and so they
spent a long time. This is not like an aha
moment one evening. You know, they did this flight in
over the last several days, but they spent months and
months and months analyzing this data, removing background noises, removing

(29:46):
other background noises, checking for sources of mistakes and uncertainty,
and calibration and cross checking and redouble cross checking, because
you know, it takes a lot of guts to publish
a paper like this to say there's something we don't
understand in our ata. Your fear at night when you
wake up in the the middle night you're like, wait a second,
did I remember to check for this thing? Is that
you overlooked something simple that you're making a mistake. It's exciting,

(30:09):
right to say we found something new we don't understand,
but it's also a little terrifying. So they definitely crossed
their tea s and dot of their eyes. These are
very careful folks, especially this one, because the discovery is
not very specific, right. I mean they're basically saying, hey,
we're getting a lot more noise in our instrument than
we think we should, which normally just means that you
you're not doing it all right, right, But here they're

(30:30):
saying that this could be something new in the universe. Yeah,
they're pretty sure this is actual signal from space and
not just an artifact of their instrument. And you know,
this is a very carefully engineered instrument, like they are
flying liquid helium up in a balloon, like they spent
a lot of time designing this thing. I read the
design paper and it's very detailed. These folks definitely did
their homework, and so I certainly believe that this is

(30:54):
a signal from space, which now lets us wonder about
you know, what is it? You know, another aspect of
writing a paper like this when you see a new
signal from space, because you're sort of putting it out there,
and you're not naming the source of it. You'd love
to see a new signal from space and at the
same time explain it because you're like, wow, look a
new signal and we discovered something. To here's the explanation.

(31:15):
That would be like a complete scientific story. Instead, you
just sort of published the experiment and then go, I
don't know, and then everybody gets to play with it.
But it sort of opens the door for somebody else
to come in and explain your discovery, right right, Yeah,
it's very open and collaborative. That's pretty cool. Alright, So
it can be other galaxies because there aren't enough galaxies

(31:35):
to make up this background roar, and it's it's probably
not a magnetic field or the cosmic microwave background radiation.
So the question is what could it be. Let's talk
about that, But first let's take a quick break. All right,

(32:00):
we're talking about the space roar or rower otherwise known
as the cosmic radio background always kind of yeah, part
of it exactly. Yeah, yeah, So we tacked off a
couple of things that it can't be can be galaxies,
it can't be magnetic fields potentially, so what could it be?
Daniel Well as usual, we have a spectrum of possibilities

(32:21):
ranging from like pretty boring to totally bonkers slash exciting.
I'm gonna guess we're gonna start with the boring and
build up to the bonkers one. Absolutely, so sort of
the most boring explanation is that maybe there are just
more magnetic fields than we thought. Remember, when charge particles
fly to magnetic fields, they bend, and bending means acceleration,

(32:43):
and when any charged particle accelerates, it has to give
off a photon. That's just basic conservation of momentum. You
can't move in one direction without pushing something else off
the other direction, and that's usually a photon. So if
magnetic fields out there are stronger than we thought they were,
then there's gonna be more of this kind of radiation
from charged particles then we thought. And if they're sort

(33:03):
of everywhere, then charged particles everywhere are going to be
basically roaring at us. And remember, we did an episode
about whether or not space itself is magnetized, because we've
been discovering as we've been trying to measure magnetic fields
through the universe, that magnetic fields are kind of everywhere,
Like there's definitely one from the Earth and the Sun
and Jupiter, and even our galaxy has a magnetic field.

(33:26):
But recently we discovered that there are magnetic fields between
galaxies and between galaxy clusters, and there might even be
magnetic fields out there in the huge voids where there's
just nothing. So it might just be that space has
more magnets than we thought, which leads to more particles
of roaring at us. Right, Maybe the universe it's just
more attractive than we thought. Yeah, it has a certain

(33:49):
glow to it, basically, right, Yeah, exactly more active than
we thought, you know, and it's more magnetic. There's more
things that you can't really quite see that are happening
in there. And you know, you need to and redients
to make a roar from magnetic fields. You need the
magnetic field, and then you also need the particles. And
as you were saying, space is not empty, right, There
particles everywhere, even between galaxies. In fact, like something like

(34:12):
half of the stuff in the universe is the intergalactic plasma,
this stuff between galaxies. So there are a lot of
particles out there flying through these magnetic fields, and if
they are larger than we expect, that could be the
source of the space roar, right, but do we know
what's causing these magnetic fields or what would cause the
magnetic fields to be that's wrong for it to generate

(34:32):
this roar. We definitely do not know the source of
these magnetic fields, which is sort of like awesome and crazy.
That's something that's basic as like the magnetic field of
the universe can't be explained. People are talking about like
weird unknown mechanisms inside galaxies or between galaxies. But my
favorite possible explanation for what's causing these magnetic fields is
that maybe they are primordial, maybe they date from the

(34:55):
origin of the universe itself. That when the universe was created,
some energy just sort of like slipped into a magnetic
field and then got stuck there. So it's like leftover
energy from the Big Bang captured in the magnetic field
still around. I see it's in the DNA of the universe. Yeah,
it could be. It could be. People have forever assumed

(35:16):
the default configuration should be like no magnetic field, no stuff,
no moving charges, no magnets, no magnetic field. But it
might just be that the baseline situation for the universe
is to have magnetic fields in it. So if you
find that stuffing interesting, check out our whole episode about
is space magnetized? All right, And that's a vanilla explanation

(35:38):
that some other universe is inherently magnetic to a super
high degree than we thought was possible. What's our next possibility?
Next possibility is stuff happening. You know, we talked about
that's a technical term, stuff happening. Isn't that just the
column definition of physics. Physics stuff happens. Yeah, but in
this case it'd be exciting stuff of happen physics, Exciting

(36:02):
stuff happens. Yes, it's exciting. Stuff is happening out there
in the universe. And in this case it might be
galaxies dancing around each other and eventually merging. You know,
these galaxies are sources of radio because their black holes
and because the big clouds of gas and dust that
are in them. And it might be that when galaxies
merge that that merging forms some turbulence, and that turbulence

(36:25):
sort of like gets these clouds of gas and dust
to emit in the radio waves louder than they otherwise would.
And so it could be that there's part of this
process of galaxy merging that we don't quite yet understand. Oh,
I see, it could be something normal happening, but that
when it happens at an extreme level, we just don't
have a good model for it. So maybe that's what's

(36:46):
generating these waves. Yeah, instead of having more galaxies out there,
the same number of galaxies, but have them do something
different from what we expected. So maybe there's more of
these mergers happening than we thought, where the mergers are
more turbulent than we thought, and that's what's giving off
this roar. So not new stuff, but old stuff doing
new and exciting things, teaching old galaxies and new tricks physics.

(37:09):
Stuff happens in any ways, all right, So it could
be merging galaxies. Well what else could it be. It
could also just be something new out there in the
universe that's giving off radio emissions that's not on our
list of things we understand. You know. It could be
not stars, It could be not the centers of galaxies.
It could be you know, not black body emission. It

(37:30):
could be some new source of radio emission that we
somehow have missed all this time. Yeah, we somehow have missed,
and people have even connected it. For example, to our
favorite universe mystery, which is dark matter. I hate. It
might be that dark matter is out there and that
it can annihilate with itself. Remember, dark matter, we know

(37:51):
is something massive that's out there, but we don't really
know what it's made out of. One hypothesis for dark
matter is that it's the really heavy particles that mostly
just sit around and do nothing. But it's sort of
hard to explain how you get dark matter and how
you have the amount of dark matter that we have
in the universe if there's no way for dark matter
to be created or for it to annihilate itself. So

(38:12):
people have thought of this idea that maybe dark matter
sometimes bumps into itself and then annihilates, just like particle antiparticle.
Maybe there's dark matter anti dark matter, and sometimes it
bumps into itself and then turns into for example, normal
matter like electrons and positrons. I see. So maybe all
this dark matter, because there's a lot of dark matter

(38:33):
in the universe, maybe that's what's causing this glow. That's
the idea, and that would make sense because dark matter
is pretty diffused out there. We're sort of surrounded by
it in a halo and in our galaxy. That would
sort of make sense. That would make a lot of sense.
So in more detail, the mechanism is that these dark
matter particles annihilate and then create these electrons and positrons.

(38:53):
But because dark matter is heavy, like it's much heavier
than electrons or positrons, these particles would be created with
sort of a lot of energy. They'd be flying through
the universe and when they hit magnetic fields they would
bend and then they would give off some radio waves.
And so it could be as you say that this
is sort of a signal of a lot of dark
matter surrounding the galaxy and giving off these electrons and

(39:15):
positrons which then roar at us. Dark matter we know
there's five times as much of it as normal matter,
and as you say, it's not spread through the galaxy
in the same way the normal matter is. It tends
to make up this big halo it surrounds everything, and
it's fluffy and diffuse, it's not as clumped, and so
that would be a good explanation. Wow, So basically dark

(39:35):
matter would not be dark, that's what you're saying. You
would have to rename it, or would you continue with
this incorrect name. It would still be darker, it just
wouldn't be quiet, right, to be like screaming matter. See
now you're mixing the metaphors there, Daniel. It's giving up light,
but you're saying it's not quiet. It's so much fun
to mix your metaphors and put silly names on things.

(39:56):
I see why astronomers are tempted. I see you just
threw them under the bus again. No, and now I'm
joining them. I'm saying, you know what, I get it
all right. So it could be dark matter. That would
be pretty exciting and pretty far out there. But it
gets been wilder, it gets even wilder. I was reading
some sort of bonkers ideas that there could be alternate
universes out there, right. This is like the multiverse theory,

(40:18):
the idea that our universe is not the only universe
as out there, there are other universes out there, and
that these universe sort of echo with ours, and there
are even ways for our universe to communicate with those universes,
for like radiation to slip from our universe to their universe.
And there's this crazy idea, this fredkin Wolf fram automaton,

(40:39):
which spreads across multiple universes that like lives in more
than one universe and gives off radio signals, and so
the idea is like, maybe this could be evidence of
other universes. WHOA, yeah, like you're seeing like the shadow
or the glow of other universes that are sort of
on top of ours, right, yeah, exactly, And I don't

(40:59):
want to be too click baby, Like this is total
speculation and it's not a prediction. Like if this is
an idea that had been invented before we heard it,
and somebody said, I think there are multiverses out there,
and you can prove it if you hear this particular thing,
go out and look for it, and then we found it.
That would be convincing. But you know, once you see
it and you don't know how to explain it, and
then later you cook up a crazy multiverse explanation for it,

(41:22):
it's sort of less convincing as an explanation. It's always
more impressive to predict something than to postdict something. Right,
But isn't that technically the same thing, Daniel. It's like
it just depends on the order in which you do it,
but it's still the same sort of connection, right, I
don't know I think the order sort of matters, Like
you know, naming lottery numbers after they've picked the lotteries
a lot easier than before. Right, it's sort of the

(41:44):
same deal like telling the past. It's a lot easier
than telling the future. So I think order matters. Yeah, right, right,
But I guess what I mean is that they could
still be right. Just because they came up with it afterwards.
Doesn't mean that they're wrong. Absolutely. They could still be right, absolutely,
But it's not really like is for their theory. You know,
it's not that hard to come up with a theory
that describes what you see. What's hard is to come

(42:05):
up with a simple theory that explains what you see,
which means it's capable of making predictions. That's what science
is about, and it's predicting the future, not just describing
the past. So you're right, we can't rule out this idea.
The only way to rule it out as to do
future experiments to compare against their predictions. So it could
totally be that we live in a multiverse and that
the space war is you know, a sound from these

(42:26):
other universes or radio emissions from these common overlapping elements
of our universes could totally be but you know, I
don't oversell it right, right, I wonder if it could
it be something more mundane, like could it just be
I don't know, like radaways coming from our technology, Like
could it be just human noise? Or I guess you
would hear it only coming from Earth. Yeah, exactly, it's

(42:46):
not connected to the Earth, right. It seems to be
coming from every direction and it's independent of the orientation
of the Earth. And also one of the reasons they
launched this thing on a balloon was just sort of
trying to get away from earth bound sources of noise.
You know, the Earth is very loud in their radio
these days because there's so many cell phones and radio
emitters are basically everywhere. A good place to do radio

(43:09):
astronomy is like on the dark side of the Moon
because it's shielded from the Earth, but it's kind of
hard to get there. So launching a balloon into space
is a good way to sort of insulate yourself away
from a lot of sources of earthbound noise. Well, I
think I got a Daniel, what is it? I think
it's cell phone signals from aliens. Like we just happened
to be in the middle of a couple of you know,

(43:30):
intergalactic alien cell phone towers, and that that's what we're
listening to. I can't believe nobody else has suggested that idea, Right,
it's obvious, and I came up with it before getting
in my hands into the data, so technically accounts. Well,
then the question is, why are these aliens roaring at
each other? Like what's going on? Can't you guys just
calm it down? You know, what's the cosmic equivalent of

(43:52):
like knocking on your ceiling with the broomstick. Well, they're
just talking on the phone, exchinging emojis and and memes,
and you know, we just don't know how to decode it.
That's all. Well, we're busy here trying to listen to
the origins the universe and understand, you know, the heating
of the first stars, and they're just like chatting with
each other and we can't make out these cosmic signals. Yeah. Yeah,

(44:12):
Well that's what life is all about, learning to live
with your neighbors, your fellow sentien beaks. All right, So
it's a big mystery in astronomy and physics. There's this
big roar. So it's still a mystery. And so what
are people doing about it than you? Well, of course
they are proposing new projects, spend more money to gather
more data. There's this plan for a new version of

(44:33):
the Arcade experiment that's gonna be much bigger. It's gonna
have five hundred gallons of liquid helium, which is going
to allow it to be even colder and say more sensitive,
like more data. Maybe we can look for some variations.
Maybe we can see if it's a little bit stronger
in one part of the sky than somewhere else. So
that's one possibility that we could just sort of like
get more resolution on the problem that might give us

(44:55):
a clue. We also have ground based instruments, and now
that Arisibo is in the past, unfortunately, that's the most
powerful radio telescope in the world is in Green Bank,
West Virginia, which is the beautiful instrument. You should google
it and check this thing out and you can make
very precise maps of the skies and these radio frequencies.
Again to look for patterns, right, because even the costing

(45:15):
microwave background has patterns to it, right, and those patterns
are important. There's a huge amount of information encoded in
those patterns. So we're just the very beginning of understanding
this other map of the sky and what's in it
and what it means. Cool alright, So maybe expect more
in the coming years. But in the near future it's
going to be a big mystery. We are bathed in mystery.

(45:37):
There's a huge source of rad of waves that is
coming from all over space, and we don't know what
it is. Yeah, we won't know for a little while
until we hear more rare in the meantime, Universe, we
hear you, We hear you roaring, We respect you, we
get it. May chill out a little bit, exactly. We're
doing our best to figure out what you're roaring is
all about. Maybe it's the universe hitting the brewstick and

(45:59):
we're seeling at us because we're being too noisy exactly.
Maybe we should learn to shut up too many podcasts.
And on that note, thanks for listening to this one,
Thanks for joining us, See you next time. Thanks for listening,
and remember that Daniel and Jorge explained. The Universe is

(46:20):
a production of I Heart Radio. For more podcast from
my Heart Radio, visit the i Heart Radio app, Apple
Podcasts or wherever you listen to your favorite shows,