Could we see moons around exoplanets?

Daniel and Jorge are over the moon about the possibility of spotting alien moons.

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:08):
Hey, Daniel, do you ever worry about the ethics of
using a telescope?

Speaker 2 (00:12):
What do you mean? What are the ethical questions about
looking through a telescope?

Speaker 1 (00:16):
I mean, like what they're looking at?

Speaker 2 (00:17):
Well, I'm not pointing them at my neighbor, if that's what.

Speaker 1 (00:19):
You mean, not your next door neighbor. What about your
next galaxy neighbor.

Speaker 2 (00:23):
Are you asking if we have the right to look
at distant objects in the sky?

Speaker 1 (00:28):
Yeah, you know, like what if there are aliens there
on a planet or a moon and we're like spying
on them?

Speaker 2 (00:34):
Well, I hope they're not offended if we catch them
sunbathing or I guess starbathing.

Speaker 1 (00:38):
Aren't all stars suns? But yeah, don't you think aliens
have a right to privacy?

Speaker 2 (00:42):
I don't know. Maybe they're alien celebrities, so they're like
starbathing stars.

Speaker 1 (00:47):
Wait, are you saying celebrities can have privacy either? Are
you secretly a starker?

Speaker 2 (00:52):
No, I'm saying astronomers are just interstellar paparazzi.

Speaker 1 (00:56):
Well, oh, it sounds like they need to draw their
curtains more. Why just have you don't get the rest
of us punch in the face, Hi am horhem a

(01:17):
cartoonist and the author of Oliver's Great Big Universe.

Speaker 2 (01:20):
Hi, I'm Daniel. I'm a particle physicist and a professor
at u C Irvine. And if it gets the aliens
to come, I want them to punch us in the face.

Speaker 1 (01:29):
Us in the face. How about just you in the face?
I mean, please, don't volunteer my face for your science.

Speaker 2 (01:36):
Us volunteering humanity's collective face.

Speaker 1 (01:41):
Some of us are sensitive in the face.

Speaker 2 (01:43):
It might be worth a puncher too, to learn that
we're not alone in the universe.

Speaker 1 (01:46):
Can we pick where they're going to punch us, you know,
like when you're playing as kids.

Speaker 2 (01:50):
You mean in the Daniel part of the face, rather
than the joey part of the face.

Speaker 1 (01:54):
Definitely the Daniel part. But anyways, Welcome to our podcast,
Daniel and Jorge Explain the Universe, a production of iHeartRadio.

Speaker 2 (02:02):
In which we try to teach you all about the
mysteries of the universe, rather than punching you in the
face with them. We think that it's possible to gently
absorb all of the crazy intricacies of how the universe works,
from its tiny little particles to its mysterious swirling black holes.
Without getting bruised, basically anywhere on your body. We seek

(02:22):
to serve up the mysteries of the universe in a
gentle and comfortable manner.

Speaker 1 (02:26):
That's right. We bring you the one two punch of
science and bad dad jokes to talk about all the
amazing things that are happening in the universe, all the
peaceful things and also all of the combatitive things, and.

Speaker 2 (02:37):
The mysteries that we love to dig into. Are the
ones that tell us about our context in the universe.
Is where we are in the universe weird and unusual?
Or are there many such backyards with many such podcasts
giving all the same dad jokes?

Speaker 1 (02:51):
Yeah, that has been one of the biggest questions in
the universe is are we alone in the universe? Or
are we one of many many alien civilization out there
in space? And are we the only ones making dad jokes?

Speaker 2 (03:04):
And how many of them are spying on us while
we're sunbathing in our backyards.

Speaker 1 (03:08):
Well, I guess you know, technically, in an infinite universe
that there's probably a planet out there where dad jokes
are like the epitome of intelligence and literature.

Speaker 2 (03:17):
Are you saying that's not our universe? Are you saying
that's not our planet.

Speaker 1 (03:20):
That is definitely not. I think there's a reason they're
called dad jokes, not just jokes. But maybe there's an
alien species out there where you know, it's like the
height of width, you know.

Speaker 2 (03:30):
Right, Well, we should try to sell our books on
that planet then, because we have a lot of readers.

Speaker 1 (03:36):
Yeah, would be intergalactic bestsellers, not just international bestsellers.

Speaker 2 (03:40):
But we're not just interested in whether our books will
sell to alien species. We're interested in whether there are
aliens out there, whether life exists in other parts of
the galaxy. And part of that question is asking whether
our whole setup is unusual. Are there stars with planets
around them? Do those planets have similar conditions to the
planets here? Is there something weird and strange about the

(04:03):
Solar System? Or is it very common?

Speaker 1 (04:05):
Yeah? Is the planet Earth a rare gem that exists
out there in the cosmos or is it sort of
like a you know, cheap chot sky that you can
find anywhere.

Speaker 2 (04:13):
In just a few decades ago, we didn't know the
answers to basic questions like are there planets around other stars? Fortunately,
as we develop new and more powerful eyeballs, We've been
able to discover those planets, and now we are pushing further.
We are asking deeper and more subtle questions about the
nature of those planets, their atmospheres, their surfaces, even what's

(04:33):
in orbit around them.

Speaker 1 (04:35):
So today on the podcast, we'll be tackling the question
could we see moons around exo planets? Now, Daniel, I
imagine these are like moons, like the orbiting celestial bodies,
and not like aliens mooning.

Speaker 2 (04:53):
Or maybe alien death stars. Right, we don't care. We
just wanted to discover them.

Speaker 1 (04:58):
Wait wait, wait, wait, I think we maybe should. If
there are alien death stars, maybe we don't want to
meet them. Maybe these are not the aliens we're looking for.

Speaker 2 (05:06):
I think we'd rather know they're there than live in ignorance,
wouldn't we.

Speaker 1 (05:10):
If we know they're there, then they know we're here.

Speaker 2 (05:12):
We could just use that Jedi mind trick, that's.

Speaker 1 (05:13):
Right, make them forget and dazzle them with our dad
jokes and then it'll be like what what And then
they won't want to associate with us, and then problem solve.

Speaker 2 (05:22):
These aren't the jokes you're looking for.

Speaker 1 (05:24):
That's right, or they'll want to annihilate us right away, But.

Speaker 2 (05:28):
We are curious about the environments of these planets. Having
moons affects life on Earth and tells us a lot
about the history of that solar system, and just in general,
we want to know, like our solar system is pretty mooney,
are other solar systems mooney as well?

Speaker 1 (05:43):
Mooney and wonderful? Because I think, as you said earlier,
up until a little bit a few years ago, a
few decades ago, we didn't even have confirmation there were
other planets out there, right, We just imagined or assume
there were, but we had not actually seen any.

Speaker 2 (05:55):
Yeah, it could have been that we were one of
very very few, perhaps singular solar systems that had planets
around it. It could have been that the reason that there's
life here around our Sun is that it was the
only one with a rocky habitable perch. Now, of course,
we know the opposite is true. We know there are
planets all over the galaxy. We've seen a few thousand

(06:16):
of them, and we estimate that there are zillions of them,
that they're almost literally everywhere in the galaxy. That's a
real change in the way we see our whole context
in the universe.

Speaker 1 (06:26):
Yeah, because imagine even like jumping from our sun to
the stars in the sky was kind of a big
leap for humanity too, right, Like, we can look at
our sun and it looks circular, at least if you
see a projector of it or through a filter, you
can see that it's a giant ball. But the stars
in the sky just look like little pinpoints, And so
it must have been a pretty big leap to think,
you know, those pinpoints are actually stars.

Speaker 2 (06:45):
It is a pretty big leap. And to understand how
big a leap it is to understand how far away
they are is pretty tricky. I mean, even the Greeks
knew that the other stars were likely suns, but they
thought they were much much closer than they actually are.
The Greeks couldn't understand how far away these stars actually were.
So yeah, it really expands your whole mental picture of

(07:06):
the universe to understand that our sun is one of
many of those stars, and that therefore there are lots
and lots of places where life might exist in the universe.

Speaker 1 (07:15):
Yeah, and those stars out there are really far away,
that's why they look like pinpoints. And so basically, until recently,
it was almost impossible to really see a planet on them, right.

Speaker 2 (07:24):
It was very tricky, and for a long time people
thought it might be impossible. But astronomers are very clever
and very hard working, and now we have lots of
tricks to discover planets around other stars, and so now
people are pushing into what many people believe is impossible,
understanding the atmospheres, the surfaces, and maybe even the orbiting
bodies of those planets.

Speaker 1 (07:46):
I wonder what did I'm sure we'll get into it,
But what's the driving question here to know whether an
exoplanet has a moon? Like do you think maybe the
moon is the one that's habitable, or you're just trying
to study other moons?

Speaker 2 (07:57):
I think all of those things. Moons might be the
most commonplace for life in the universe. It might be
that moons around big planets are the best place for
life to evolve, and the humanity is very, very weird
for developing directly on the surface of a planet. On
the other hand, moons also tell you a lot about
the history of the Solar System, how it formed, how

(08:19):
it came to be, which tells you a lot about
where you expect to find planets that might have life
on them. So it's as much about understanding the detailed
history of other solar systems and thinking about where we
might find life well as usually.

Speaker 1 (08:31):
We were wondering how many of you out there had
thought about this question and wondered if we could see
moons in other planets.

Speaker 2 (08:37):
Thanks very much to everybody who offers their unprepared insights.
We really enjoy this segment of the podcast and we
want to hear from you. Please don't be shy write
to us to questions at Danielandjorge dot com.

Speaker 1 (08:49):
So think about it for a second. Do you think
we could ever see moons around exoplanets? Here's what people
have to say.

Speaker 3 (08:56):
Just finished listening to the podcast with the exoplanet researcher
and do I think we could see them? No, but
we do have confirmed existence of moons around exoplanets. I
believe that number is currently at two.

Speaker 4 (09:10):
I think we will definitely be able to see moods
throughout exoplanets. James Web will be able to analyze the
atmospheres of exoplanets and it might even be strong enough
to see moons. And if not, James Web, there's probably
going to be another set of eyeballs in the future
that we'll be able to do it.

Speaker 5 (09:26):
I think that in order to be able to detect
moons of exoplanets, we would need very sensitive telescope and
other instruments capable of measuring the lightest, faintest of changes
in the light emitted from other stars.

Speaker 6 (09:43):
Yes, in terms of finding excello planet moons to be
to measure the gravity between that planet, that exoplanet a
star and see if we can account for any extra
gravity that would be from the moon or maybe some
sort of nudger or tug on that moon.

Speaker 7 (09:58):
I think this depends on your definition of what it
means to see a moon. It seems like it would
be nearly impossible to imagine directly imaging any especially given
that we haven't directly imaged and exo planet yet. But
if we had a specially large planet around a star
with a big enough percentage of its star's mass, and
if it in turn had a moon that was a
significant percentage of its mass, then I would imagine that

(10:19):
they could probably detect the combined wobble of the interaction
between those three.

Speaker 1 (10:25):
All Right, a lot of optimism here. I feel everyone's like, sure, yeah, eventually,
sort of in one way or another, Yeah.

Speaker 2 (10:31):
There's this bubbling sense that eventually we could figure out
basically any problem that in our future lies more and
more powerful techniques and telescopes and smarter people that could
extract this kind of information from the universe. I love
that it's so inspiring to hear people's optimism. Yeah.

Speaker 1 (10:47):
Yeah, And I think by smarter people you mean the engineers, right.

Speaker 2 (10:51):
I mean my students and my students'.

Speaker 1 (10:53):
Students and the engineers that actually do it for them, right.
I think that's what you're saying.

Speaker 2 (10:57):
Right, I know, we just submit the work order and
it comes back. You know who knows who does YadA,
YadA YadA. You gotta telescope.

Speaker 1 (11:03):
That's right, We toy anonymously. That's what happens to all
smarter people.

Speaker 2 (11:07):
No, of course, the field of astronomer is filled with
people who analyze the data, and people who build the devices,
and people who plan for the next generation of devices.
It's a whole ecosystem of smart people, from physicists to
planetary scientists, to engineers to computer scientists, all sorts of
people all working together.

Speaker 1 (11:24):
Well, this is a pretty big question, or I guess
a small question is how do you see the moon
around a planet orbiting a star that is light years
or at least millions of miles away. It's a pretty
tough question.

Speaker 2 (11:36):
It is a pretty tough question, and it's going to
require us to get even better at seeing those planets.
All the techniques we have for seeing moons are basically
like super powerful versions of the ways that we see planets.

Speaker 1 (11:49):
All right, well, let's break it down for people, Daniel.
First of all, what is an exoplanet and what do
we know about them?

Speaker 2 (11:55):
So an exoplanet is very simply just a planet around
another star. Planets are the planets around our sun. An
exoplanet is a planet around for example, Alpha Centauri or
any other star that's not our Sun XO. Just meaning
like outside the Solar system.

Speaker 1 (12:11):
M I see like an outer planet? Where I guess not,
because an outer planet could be the planets in our
Solar system. Like anything outside of our Solar system that's
a planet is an exoplanet.

Speaker 2 (12:21):
Yeah, a planet around another star would be an exoplanet.
And they have to be far away because the nearest
star is several light years away, which is really really far.
It's very far compared to the distance between the planets,
and so an exoplanet is going to be very, very
different from any planet in our Solar system, just in
terms of like where it is.

Speaker 1 (12:40):
And we hadn't actually seen one or confirmed there were
any planets around any other stars until basically like thirty
years ago.

Speaker 2 (12:47):
Right, Yeah, it's incredible if you make a plot of
like the number of planets we've seen over time, dating
back like thousands of years until fairly recently, we'd only
ever seen like six, right, and then Urinus and Neptune
are discovered in the last few hundred years, and then
Pluto and then un Pluto, so we're back down to eight.
And then it wasn't until the nineteen nineties, only thirty

(13:08):
years ago, that we finally saw one outside of our
Solar system. Until then, we only speculated, we only imagined,
we'd had calculations, we had speculations, but we had no
actual data until about thirty years ago when we developed
these techniques to see the planets or to deduce their
existence around other stars.

Speaker 1 (13:26):
Yeah, because, as one of the listeners who replied earlier said,
the word see is a little bit tricky, right, We
didn't actually see planets in other stars. We sort of
like figure out they were there, but we didn't actually
see them.

Speaker 2 (13:37):
Yeah, exactly, and so we have these really cool techniques
to deduce that they exist, and you know, you can
argue philosophically about what does it mean to see something,
But we didn't see exoplanets directly until much more recently.
The first discoveries came from just observing the impact of
those planets on the stars, which of course we can.

Speaker 1 (13:57):
See, which is kind of crazy to think, right, because
what possible impact and the Earth have on the Sun.
The Sun is like a million times heavier than the Earth,
right or more.

Speaker 2 (14:06):
It's all about making these things more sensitive and getting
down to the details. Like mostly you're right, the Earth
has basically no impact on the Sun. But if you
analyze the Sun super duper closely, then yeah, the Earth
does have a little bit of an impact on the Sun,
the same way that, for example, the other planets have
an impact on the Earth. Mostly, the Earth's orbit around
the Sun is just a story of two bodies, the

(14:27):
Earth and the Sun, orbiting their combined center of mass.
But if you get super dup or precise about it,
then you have to take into account, like the effect
of Jupiter and Saturn on the orbit of the Earth.
So all of these little complications can actually reveal the
rich structure of the Solar system if you study them
with enough precision.

Speaker 1 (14:45):
It's pretty mind body to think. I mean, the Sun
is so big and it's the Earth is just this
tiny little marble next to it, like that it would
have an effect on the whole thing. Like I can
see maybe pulling a little bit more on the part
of the Sun that's closest to the Earth, maybe some
of that cosma, But to think that it could move
the entire Sun is pretty hard to believe.

Speaker 2 (15:03):
Yeah, Well, imagine instead you had two objects that had
the same mass, right, like two stars the same mass,
and they're orbiting each other. Clearly they have an effect
on each other. What they're orbiting is actually a point
right in between them. Now, as you shrink one of
those things down and grow the other one so it
becomes asymmetric, the points they're orbiting moves towards the center
of the heavier one. If one of them was infinitely

(15:26):
massive or the other one was massless, then they would
both be orbiting a point at the center of the
biggest object. But if the Earth is not massless, if
it actually does have some mass, then it's pulling that
center of mass a little bit away from the center
of the Sun. And if you measure the motion of
the Sun very precisely, you can detect that. And that's
why these things are so hard. That's why it took

(15:46):
so long to see these things, is that it requires
really precise measurements now of the motion of stars in
other solar systems.

Speaker 1 (15:53):
Yeah, it's pretty mind blowing. But I guess maybe one
thing that helped was that we didn't start looking for
Earth sized planets, right, we start looking for Jupiter sized planets.

Speaker 2 (16:02):
Well, we started looking for anything we could see, and
we didn't know what was out there, right. We had
speculation about what kind of planets might exist in other
solar systems, but we didn't really know what we could find.
You're right though, that the first techniques we developed were
more powerful for Jupiter sized planets. The bigger the planet
and the closer it was to the star, the easier
it was for us to find them.

Speaker 1 (16:23):
Like, those were the first planets found right where. They
were basically giant gas planets.

Speaker 2 (16:27):
Yeah, they call them hot Jupiters because they're the size
of Jupiter and they're very close to the star. The
closer they are the star, the faster the orbit, the
easier it is to find them because they tug on
the star. And so one of these techniques is called
the radial velocity method. You look at the light from
the star and you see if it's shifted in frequency.
If a star is moving away from you, it's red shifted.

(16:48):
If a star's moving towards you, it's blue shifted. If
a star is getting wiggled by a planet that's orbiting it,
then it's going to get red shifted and blue shifted,
red shitted and blue shifted. It's going to wiggle a
little bit in its frequencies. And that's what they look for.
But that's more powerful for big planets and planets that
are close to their stars.

Speaker 1 (17:06):
But then we develop other ways to look at planets,
right really quick, What are some of these other ways
that we can see exoplanets.

Speaker 2 (17:12):
So another way is the transit method, which is basically
an eclipse. As the planet passes in front of the star,
it dims it a little bit, it blocks some of
the light. And so again if you're just measuring the
light from the star roughly, you're never going to notice this.
If you make very precise measurements of the light from
the star, you can see these dips and you can
see the patterns. If the planet goes around many many times,

(17:32):
you'll see the same pattern over and over again. Unfortunately,
this one is also best at seeing big planets that
eclipse the light more and close by planets that block
more light from their sun and go around many times,
so we can see many transits.

Speaker 1 (17:47):
Yeah, like if the Moon didn't reflect any light and
you can see it in the night sky, you could
still maybe every once in a while know it's there
because it would block the light from the Sun. You
would see an eclipse exactly.

Speaker 2 (17:56):
And there are techniques that will let you see planets
that are further from the Sun, and these are actually
the direct imaging ones. We can look at a solar
system and we can block the light from the sun
called the corona graph, a little thing that prevents the
light from the star from getting into the telescope and
only look at the stuff around it. And now we
have powerful enough telescopes that you can actually see dots
around those stars. So these are direct images of light

(18:20):
from those planets, and those are most powerful at seeing
planets that are far away from the star. There's the
further they are from the star, the easier it is
to tell them apart from the blinding light from the
star itself.

Speaker 1 (18:30):
Yeah, it's like you basically put your thumb, like if
you look up at the skuy you put your thumb
over the star and then you see there are any
other twinkles around it, right.

Speaker 2 (18:38):
Exactly, And so we have like a few pixels of
light from these planets. Of course, the planets themselves are
not glowing. It's all reflected light from their star. But
you know, it bounced off the planet first, so it's
just like looking at the planet the same way the
Earth is illuminated by our sun.

Speaker 1 (18:53):
That's the closest we have of an actual picture of
another planet, right, Like, I've seen the plots. They're a
bit old right now. We've had these photos for fish
seen hears or something like that.

Speaker 2 (19:01):
Yeah, they're getting better and better, but they're not great.
I mean they're pretty fuzzy. If you took pictures of
your kids like this, none of your relatives would be
very impressed with your photography. It's like a few pixels
here and there.

Speaker 1 (19:11):
Yeah, although my kids nowadays avoid getting their picture taken
as I think most kids do, and so they're kind
of a big blur anyways, And then what's the last
kind of method we used to detect these exoplanets.

Speaker 2 (19:24):
The last technique is called micro lensing, and that's essentially
using the planet as a lens to distort light from
some other star. If there's light from another star behind
the Solar system that's passing through that Solar system, then
it can get bent around the planet. Because the planet,
of course is massive and it changes the shape of

(19:44):
space and so it can act like a giant lens.
This is sort of similar to the way we can
see dark matter in the sky by seeing its gravitational lensing.
So here's called micro lensing because there's so smaller amount
of lensing as the light passes around the planet.

Speaker 1 (19:59):
Yeah, you're seeing how the bends the light coming at you.
And so those are the different ways that we can
see exoplanets. But now the big question is are there
moons around these exoplanets out there in the universe? What
is it like on those moons, could we ever see them?
And how are we going to see them? So let's
dig into that. But first let's take a quick break.

(20:30):
All right, we're talking about finding exo moons, So you
call them exo moons if it's a moon around an exoplanet.

Speaker 2 (20:37):
Yeah, we call them exo moons unless you have a
better name for.

Speaker 1 (20:40):
Them, turning to be like exoxo moons because it's like
a different body out on an exoplanet.

Speaker 2 (20:48):
There are exo moons around exo planets. There are two
exos there. But I think exo just means in another
solar system.

Speaker 1 (20:55):
So well, what do you call the moons around Jupiter?

Speaker 2 (20:57):
Moons?

Speaker 1 (21:00):
Moons?

Speaker 2 (21:02):
Yeah, there you go, and no moons now, just moons.
And you know, Jupiter is a great example because something
we noticed and our solar system is there are kind
of a lot of moons, right, we have two hundred
and twenty six moons in our solar system. And something
we wonder is like, is that weird? Are we kind
of moony? Or are we moon poor compared to other
solar systems? Like what's a typical number of moons to have?

(21:25):
We just don't even know.

Speaker 1 (21:26):
And we have a whole episode about how like moons form, right,
how you get a moon?

Speaker 2 (21:30):
Yeah, exactly. It's really fascinating the number of ways that
you can get a moon, they can form with a planet,
you can capture them, it can be the result of
a collision. The point is that it tells you a
lot about the history of the Solar System. It's like
a record of what happened here before you showed up.

Speaker 1 (21:46):
Right, Like our Solar System we've talked about before, it
was a pretty chaotic place, and so it kind of
makes sense that there was just a lot of debris
out there floating, flying around, and so not all of
it was going to get into planets, and so it
makes sense we have a smaller box that they're orbiting
the bigger bodies.

Speaker 2 (22:02):
Yeah, although we have an incredible range of sort of
size of those bodies. Like our moon is huge. It's
like more than one percent the mass of the Earth,
which is very very unusual. More typical size is like
one ten thousands the mass of the planet. But then
there's also like Sharon, which is one eighth the mass
of Pluto, even though Pluto not officially a planet anymore.

(22:22):
But we have this incredible variation in the sizes of
the moons and in their origin and their composition. It's
really an incredible diversity.

Speaker 1 (22:30):
Or I guess in the relative size, right, because some
of the moons around Jupiter, aren't they almost the same
size as our moon?

Speaker 2 (22:37):
Yeah? Exactly, we're talking about the relative sizes, and some
of the moons around Jupiter are huge, absolutely, and potential
places for life to exist, which is one of the
things that makes us wonder whether Moon's around exoplanets might
also be habitable.

Speaker 1 (22:49):
All right, Well, we talked about how we can see
other planets in other stars in the universe, and I
guess as as star wars were like, Okay, we've seen those.
Now let's increase the difficulty. Exactly, fine, things orbiting not
just around other stars, but around the things that are
orbiting around other stars.

Speaker 2 (23:05):
And this is the game in science, right. People have
come along and done the simplest thing. All right, now,
let's come along and do the next harder thing. And
then the next generation's like, well that was easy. Now
let's do the next harder thing. And so I love
how we're always making the progress. We're always pushing the
boundaries here.

Speaker 1 (23:19):
But are we done though? I feel like I'm still
waiting for that, you know, actual picture of another planet
in another solar system, you know, like a like a photograph, photograph.

Speaker 2 (23:28):
Yeah, No, we're never done right. We're always pushing, but
we're pushing in lots of directions. Simultaneously, people are working
on that photograph. One idea that's being worked, one which
we talked about in the podcast, is like using the
Sun itself as a gravitational lens. You put a camera
out deep in the solar system. You can use the
Sun to gather a huge amount of light from a
distant solar system, and the Sun will focus all that

(23:49):
light on the camera you have out like near Neptune,
treating the Sun like this huge lens and making a
solar system sized camera that could give you a picture
of the surface of exoplanets.

Speaker 1 (24:00):
Wait what like our sun?

Speaker 2 (24:02):
Yeah, our sun. You have the Sun acting like a
gravitational lens, gathering light and then focusing it on a
camera you put like way deep in the soil system,
and you can take a picture of something super far
away with a lens effectively the size of the Sun.

Speaker 1 (24:16):
Whoa pretty cool, let's do it, Picker, It didn't happen.

Speaker 2 (24:21):
It's pretty tricky project because you have to get a
camera like pretty far out in the solar system and
that could take decades, and then moving it takes a
long time, but it definitely can be done, and someday
we will see the surface of exoplanets.

Speaker 1 (24:33):
And then you got to get the aliens to stay
still and smile for the camera, and it takes, you know,
a thousand years just to say cheese.

Speaker 2 (24:40):
Yeah. Then they have to sign that waiver, you know,
so you can publish the picture.

Speaker 1 (24:45):
There you go. You seem really concerned about the aliens here.

Speaker 2 (24:49):
Hey man, I'm just looking after them. I just don't
want them to come and punch us in the face
over something silly like legal forms.

Speaker 1 (24:56):
You don't want to punch you in the phase when
you take a picture of them in the bathroom, I.

Speaker 2 (25:00):
Have no idea when they're in the bathroom, Like, what
are you doing over there? Is that what you call
the bathroom? I don't know. I'm just taking pictures.

Speaker 1 (25:06):
I see ignorance.

Speaker 2 (25:08):
Yeah, look, look, I just want to say, there's a
lot of moon jokes I'm not.

Speaker 1 (25:11):
Making around here, thankfully, thankfully. All right, Well, then how
can we see these ex moons? We basically use the
same methods we used to detect other planets, or are
we trying some different things?

Speaker 2 (25:22):
Both The bread and butter is to take the same
methods and make them super duper sensitive. Like the transit
method is one of the most sensitive methods for finding
these planets if everything is lined up, and you can
also use it to discover the Moon's in a couple
of ways, because the moon will affect how the planet
blots out the light from the star Number one, it

(25:42):
can affect when it happens like the moon is tugging
on the planet the same way the planet is tugging
on the star, which makes when the planet gets in
front of the Sun and blocks its light change a
little bit. As the moon is orbiting the planet, it's
like yanking on the planet a little bit, So it
changes the timing in these transits, right.

Speaker 1 (26:03):
Like I guess, like our moon, the moon here is
making the Earth wiggle a little bit. And so the
idea is that in another planet, in another solar system,
if it has a moon, a big enough moon, it's
making that planet wiggle, and so when it moves in
front of its star, it's going to block the light
in a wiggly fashion exactly.

Speaker 2 (26:20):
And if you count enough of these transits, you can
start to notice these patterns, and then you can fit
it to a model you can say, like, well, can
I explain why this transit was a little bit later
and that transit was a little bit earlier. By assuming
that there's a moon there pulling on it, is it
all consistent? You don't just like look for noise and say, well,
I don't know it was noisy, maybe there was a moon.
You have a specific description of what that moon might

(26:42):
look like and how it would affect the planet.

Speaker 1 (26:45):
Right, Like, if you notice it the wiggling is regular,
then you know there's something going on, Like it can't
just be like random wiggling exactly.

Speaker 2 (26:52):
And there's a second way, which is that the moon
itself can also contribute to blocking the light, not just
when the planet blocks it, but the moon could also
have its own little moony eclipse, right because if the
moon is lined up at the same time as the planet,
it can add a little bit of eclipsiness to the planet.
It effectively makes the planet's shadow a little bit bigger.
And if you have a model for how that moon

(27:13):
is orbiting the planet and when the planet is going
around the Sun, you can predict exactly when the Moon's
going to be in the right position to add to
the eclipse.

Speaker 1 (27:22):
But wouldn't it always block the lights in the sun, Like,
you know, it's pretty small compared to that planet, and
the planet is small compared to the Sun. Wouldn't it
always be sort of insight or in view.

Speaker 2 (27:33):
It might always be in view, but it doesn't always
have to contribute to the amount of eclipse. Like let's
say they're all lined up. If you see like moon
and then planet, then star. If the moon is already
in the shadow of the planet, then it's not contributing
to the decrease in the light. Only when the Moon
is sort of offset a little bit from the planet,
so it like adds a little shoulder to the planet.

(27:54):
Is it going to increase the amount of light that's
being blocked? And that's the kind of thing they look for.
They look for these trans dips with like a little
wiggle on the down edge or a wiggle on the
up edge when the moon is peaking around the side
of the planet. Basically have to have moon rise or
moon set along the planet for it to contribute to
the transit dip.

Speaker 1 (28:12):
Wow, but now we're talking about like a super duper
tiny dip in the light, right Like our moon would
block very little of our giant Sun.

Speaker 2 (28:20):
Yeah, exactly. We're talking about really sensitive measurements, and until
recently people allowt this is impossible. You know, you'd need
very very accurate understanding of the light and very precise
measurements of the intensity of the light coming from these things.
So it wasn't until like two thousand and seven, more
than a decade after exoplanet discoveries, the people really started

(28:40):
working on this in detail, like taking the idea seriously.
And one of the biggest challenges is that most of
these techniques that we've used to find exoplanets are good
at finding planets close to the star, like we talked
about hot Jupiter's right, really big planets really close to
their stars. But those planets are unlikely to have moons.
And though that makes it very challenging to find any

(29:02):
of these moons.

Speaker 1 (29:03):
Why are they unlikely to have moons?

Speaker 2 (29:04):
For the same reason that Mercury and Venus don't have
moons in our Solar system, right, all the other planets
have them, and Mercury and Venus don't. It's because of
the tidal forces from the Sun. As you get close
to the Sun, the tidal forces, the difference in gravity
from one side to the other side of a planet,
for example, get very very intense, and that will just
disrupt the orbit of a moon. In order to have

(29:25):
a moon orbiting a planet, you basically need the Sun
to leave it a little bit alone. You need a
planet to be able to dominate the gravitational experience of
that moon, so the moon can be trapped in an orbit.
But if the Sun is really really close by, then
the Sun's tidal forces make a moon's orbit impossible.

Speaker 1 (29:43):
Like they'll tend to pull the Moon towards the Sun
and then eventually that moon will either fly off into
space or fall into the Sun exactly.

Speaker 2 (29:50):
Essentially, it's like a three body system, which we've talked
about before, is fundamentally chaotic. The only arrangement for a
three body system to be stable is if two of
those bodies are pretty close together and pretty far from
the third body, which is like, if you have a
distant planet with the moon orbiting it, that planet gets
too close to the Sun, you now have a three
body problem and you're going to lose your moon.

Speaker 1 (30:09):
So you're saying that's kind of a problem because our
exoplanet detection methods depend on being close to the Sun.
But those planets might not have any moons exactly.

Speaker 2 (30:17):
So the kind of planets we're good at finding are
the kind of planets we expect to not have very
many moons. On the other hand, there's lots of planets
out there, and we can sometimes see planets a little
further from their star, and maybe one of those hot
jupiters will have a big enough moon that's orbiting close
enough to it to be stable. So there's not no hope.
But it's pretty tricky.

Speaker 1 (30:38):
But I thought the transit method, the one where we're
looking for eclipses and distant stars, those don't depend on
the closeness of this planet.

Speaker 2 (30:45):
They do indirectly depend on the closeness of the planet.
What you want is a short period, because you want
to see many transits. If your planet is really far
from your star and orbits like once every eighty years,
then you're most ever going to see one transit, And
it's pretty hard to be sure that what you're looking
at is a planet if you only see one eclipse.
If you see it regularly and it happens every four days,

(31:06):
and you can really study it in detail, and you
can convince yourself that you're seeing a planet, not for example,
like a star spot, something on the surface of the
star that's dimmer and darker and decreasing the intensity of
the light.

Speaker 1 (31:18):
The period of the orbit makes a big difference.

Speaker 2 (31:21):
Yeah, exactly, because you want more examples.

Speaker 1 (31:23):
Right right, Yeah, Like some of the planets in our
Solar system take like two hundred years right to go
around the.

Speaker 2 (31:28):
Sun exactly, And so if you're an alien graduate student
and you're trying to discover Pluto in our Solar system,
then you're going to be a student for a long
long time.

Speaker 1 (31:36):
Yeah, it's going to take even longer to get that
PhD thousands of years.

Speaker 2 (31:42):
I hope you guys live long out there.

Speaker 1 (31:43):
So then what about direct imaging, like taking a direct photograph?
Is in that better for planets that are far away
from the star.

Speaker 2 (31:50):
Yeah, that's possible. We're sort of just on the cutting
edge of being able to do that even for planets,
and so we're pushing those limits and we're developing new
technologies and this whole new generation of space based telescopes
that are gonna be super awesome at doing direct imaging
of those planets, and so as that gets better, it'll
start to be possible to potentially see moons around those planets.

(32:12):
But you know, as we said, like currently planets are
basically one or two pixels, so resolving a moon around
those planets would be really challenging. With a couple of exceptions,
if those moons have ways to like really make themselves known,
then we might be able to see them.

Speaker 1 (32:27):
So Like, for example, if you look at Jupiter here
in our Solar system with a regular telescope in your backyard,
you can actually see the moons of Jupiter, right. You
see little points around the bigger circle of the planet.
It is that if you point a bit powerful enough
telescope and these distant planets, you could see maybe the
dot front the planet, but also maybe little dots around
it that might be the moons.

Speaker 2 (32:48):
Yeah, you might, especially if those moons are weird in
some way, Like if those moons are super volcanic and
they're shooting out really hot gases, you might be able
to spot that. Or if the moon munds are super
duper hot, like they're squeezed by their planet with tidal
forces so that internally they're very high temperature, then they
might glow at a different temperature than their planet and

(33:09):
be easier to see them, and so there's some weird
kind of moons that you might be able to direct
image before regular normal humps of rock. But I think
we're gonna have to wait for our direct imaging technology
to improve significantly before we can expect to see pixels
from exo moons.

Speaker 1 (33:26):
Interestingly, I wonder if you can like do like the
cliffs method on a planet that's far away, you know
what I mean, Like if if you're looking at the
life from reflected from a planet and you see a
dip itself, I wonder if that could be a sign
that there's the moon there.

Speaker 2 (33:39):
Yeah, that's a cool idea. And you're right, the reflected
life from that planet should dip when the moon passes
in front of it. Again, we're still at the cutting
edge of even seeing pixels from those planets, and so
there you'd need like to study those pixels over time
and to look for dips and to understand every other
possible source of dips. Because that planet is light, is

(34:00):
already going to be variable as the planet goes around
the star, So you're gonna have to understand that and
then variations on that. But yeah, that's a cool idea.

Speaker 1 (34:08):
Thanks, I'll take the Noble Price. We have it on record.
All right, Well, these seem like long shot sort of
sounds like from what you're saying that we're not super
close to being able to do this. But have we
have we found any moons out there and other planets?
Have there been any discoveries?

Speaker 2 (34:23):
So we are right on the edge of being able
to do this, which means that we have like a
couple of candidates that are disputed. There are some people
who think these probably are exo moons and other people
who think they're probably not. You know, the evidence is
like really right on the edge, and people split over
the statistical analysis of these things. But it's fun because
we have a couple of things to dig into and

(34:43):
to talk about.

Speaker 1 (34:44):
All right, let's do it. What are these candidates for
possible exomoons?

Speaker 2 (34:48):
So there was one discovered in twenty eighteen. This is
the first exo moon candidate, and it's around planet Kepler
sixteen twenty five B. Kepler sixteen twenty five is the star,
B means the planet, and then the moon is called
Kepler sixteen twenty five B. Dash.

Speaker 1 (35:05):
I Well, why I was there an abcd FGH moon
or are they're just going for like an iPhone reference here.

Speaker 2 (35:13):
No, I think it's Roman numerals, Like the first one's
going to be I, the second one's going to be II,
the third one would be III.

Speaker 1 (35:19):
This kind of thing, uh I see, all right, Yeah,
switching it up exactly.

Speaker 2 (35:24):
And so here's this two separate, independent pieces of evidence
that suggests that there might be a moon here. What
we're looking at is a Jupiter size planet around the
star right, but it's like earth distance from the Sun,
but it's like a huge planet.

Speaker 1 (35:39):
That's what we think is there.

Speaker 2 (35:40):
That's what we think is there. That's the planet that
we're pretty sure is there. That's Kepler sixteen twenty five B.

Speaker 1 (35:45):
It's mass, but maybe not necessarily it has to be
gas giant, does it.

Speaker 2 (35:50):
We know some of about it's mass because we know
it's orbit and so we know roughly its volume, and
we know it's roughly it's mass, and so we can
tell something about the density. And these planets of this
size are almost always gas giants.

Speaker 1 (36:00):
All right. So that's what we think is there.

Speaker 2 (36:03):
And so it's sort of an unusual planet already because
it's a cool Jupiter. We talked earlier about how lots
of the planets we've discovered are hot Jupiter's big planets
very close to their star, like within the orbit of Mercury,
you know, but this is farther out orbit makes it
a cool Jupiter. And the first thing they noticed is
this transit timing variation that the planet is blocking the

(36:23):
light from the star behind it. But it's not in
a regular fashion. There're wiggles there and exactly the way
you would expect if there.

Speaker 1 (36:30):
Was a moon, I see. So it's not like going
around its Sun in a regular way. It has a
little wiggle to its orbit exactly.

Speaker 2 (36:37):
It has a little wiggle to its orbit, which can
be explained very nicely by the presence of a moon.
Like they do all the statistical calculations, they have two
models like with and without the moon, and the one
with the moon better explains the data, like much much
better explains the data than the model without the moon.

Speaker 1 (36:54):
Although couldn't it be something else as well?

Speaker 2 (36:56):
It could be something else, right, It could be that
there are other planets in this solar system and those
planets are tugging on it, and that'd be much more
complicated because you could have multiple planets like several Jupiter
sized planets that are yanking on it. It's very difficult to model.
And that's one reason why this is not a smoking
gun discovery, because there are other ways that you could
get this kind of signature. What they did follow up

(37:19):
is they looked at some Hubble data. They looked at
Hubble data pointed at this star to see if they
could see an impact of the Moon on the transit itself,
not just the timing, but like, could we see wiggles
in the dip right? Are there like shoulders in this
transit that indicate that we're seeing like a moon rise
as the planet is blocking the light from the star.

Speaker 1 (37:39):
Like, is the moon from this cool Jupiter also blocking
the light from the star Sometimes.

Speaker 2 (37:44):
Yeah, exactly. And we only have unfortunately, one really clear
transit because this comes from Hubble, and Hubble is not
a planet finding telescope. It's busy doing lots of things.
It's not always looking at one star. So they have
only like forty hours of data from this star with Hubble.
But they did see a clear transit and there is
a dip there that looks like a Neptune size moon

(38:06):
around this Jupiter sized planet.

Speaker 1 (38:09):
Whoa that would be a huge moon wouldn't it.

Speaker 2 (38:11):
Yeah, literally, that would be huge.

Speaker 1 (38:14):
More like a sister planet almost.

Speaker 2 (38:15):
Yeah, although technically if it's orbiting a planet, then it's
a moon.

Speaker 1 (38:19):
But what if they're both planets.

Speaker 2 (38:20):
Yeah. This gets into a really murky territory of where
you define things to be binary planets and where one
of them is a moon. They have this definition where
if the center of mass is inside the surface of
one of them, then one of them is a planet
and the other one is a moon. And in this
case that Jupiter is so much bigger than the Neptune
that the Neptune qualifies as a moon.

Speaker 1 (38:41):
You only have one data point. Why don't we get more?

Speaker 2 (38:44):
I think that people are excited about that and are
working on it, But you know, hubble time is very
very precious, and there's lots of good things to use
hubble for. In the meantime, people have been like analyzing
this and reanalyzing this, and other groups have analyzed this data,
and not everybody agrees with the interpretation that the first
paper came up with. Some people look at the transit
data and they say, no, there's no dip there from

(39:04):
a moon. It doesn't look like there's any shoulder there.
Another group analyzed it and said they do agree with
the shoulder, but they disagree with the uncertainties and the
other measurements. And the point is that the data is fuzzy,
it's not crisp and clear, it's not obvious. It requires
like heavy duty statistical techniques to extract this information, and
so we just really can't be one hundred percent confident.

Speaker 1 (39:25):
Wow. So they posted this paper with just one data point.

Speaker 2 (39:29):
Well, they have one example of the transit, but they
also have the transit timing, right, So those are two
independent streams of information. One is the timing of the
transits and the other is like the actual photometric like
looking at the dip in the light, seeing the moon
itself actually eclipse. They have lots more of examples of
the Moon tugging on the Jupiter and changing its transits,
but only one example of the moon itself blocking the light.

Speaker 1 (39:52):
And they sort of match together. I guess right.

Speaker 2 (39:55):
They do match together according to one group and their analysis,
and they don't match together according to another group.

Speaker 1 (40:01):
Sounds like they need more data.

Speaker 2 (40:02):
We definitely need more data. We need more telescopes and
more eyeballs. It's so frustrating when our knowledge of the
universe is just limited by like how many eyeballs we've built,
because there's nothing stopping us from building more. It's just money.

Speaker 1 (40:15):
It's just money.

Speaker 2 (40:16):
It's just money.

Speaker 1 (40:17):
It needs money.

Speaker 2 (40:19):
We can just print more. Come on, let's do it.
Print some more money, makes it more scope. Done, Let's
do it. Hey, a lot of engineers will be put
to work building the Daniel Fund the telescope.

Speaker 1 (40:32):
Yeah, I'm sure, I'm sure.

Speaker 2 (40:34):
Okay, I will print my own money and I'll see
if engineers out there will accept it as payment one
hundred thousand Daniel bucks.

Speaker 1 (40:40):
Well no, Well, I mean, if you commit fraud that way,
who's going to believe your scientific findings?

Speaker 2 (40:46):
Yeah, exactly, And that's why there's no Daniel Space Telescope.

Speaker 1 (40:51):
All right, Well, what's another discovery we made in this
attempt to find other moons?

Speaker 2 (40:55):
So there's a second potential discovery. This one's Kepler seventeen
oh eight b dash I. And this was a really
cool strategy to look specifically for planets that have long
periods that are further away from their stars, because they're rarer,
at least in our catalog. At least they're rare in
the kind of things we can see, but they are
more likely to have moons, we.

Speaker 1 (41:16):
Think, because that's kind of the trend in our Solar system, right,
Like we have one moon Mars is two in the
inner Solar System, but in the outer Solar System, like
Jupiter and Saturn have dozens of moons.

Speaker 2 (41:27):
Yeah, exactly, because further you get away from your star,
then the more freedom you have to like dominate your
gravitational environment, capture moons or retain moons or all that
kind of stuff. So they thought, well, let's focus on
cool giants, these planets that are further away, and then
the whole catalog of exoplanets we've ever discovered, they're only
like seventy that qualify is these cool giants.

Speaker 1 (41:49):
I see. If they're not cool, they're not included in
the study. You're not invited to the party. Only cool giants.

Speaker 2 (41:56):
Hot giants is a totally different party with a totally
different vibe. Yeah.

Speaker 1 (42:01):
Here, it's more of a hipster you know scene.

Speaker 2 (42:03):
Yeah, we're listening to jazz around here, so sit down,
have a drink, chill out.

Speaker 1 (42:08):
I'm not sure jazz is considered cool by the kids
these days.

Speaker 2 (42:12):
All right, thanks for filling me in, all.

Speaker 1 (42:13):
Right, well, let's dig into this cool giant moon what
we know about it and what it tells us about
how solar systems form. But first, let's take another quick
break or right, we're talking about cool giants, not the

(42:38):
you know, plain old giants, not the lame giants, but
the cool giants, and seeing if they have any moons
in them. That's right, The moons have to be cool too.

Speaker 2 (42:50):
Some of these moons could be hot, right, they could
be volcanic, They can have all sorts of stuff going
on inside. Even if the planet itself is pretty.

Speaker 1 (42:57):
Cool, that would be cool, all right. So we've been
talking about finding moons and other planets outside of our
Solar system in distant stars, and there are many different
ways to do it that are getting better and better
every day. And so we have a couple of candidates
of things that might be moons exo moons out there,
and one of them is this one called seventeen oh
eight b I.

Speaker 2 (43:17):
That's right, and this one was just discovered last year,
twenty twenty two. And they looked again at the transits
they're looking for like shoulders when this planet is going
around the star, are there moments when it's blocking more
light than you expect, which could be explained by having
a moon orbiting that planet and like rising past the
limit of the planet or coming around the back and

(43:39):
blocking the light. And so they were looking for these
little shoulders, and it's really pretty cool they do see
some they see these little shoulders inside this transit lip.

Speaker 1 (43:48):
And I think by shoulder you mean like if the
planet didn't have a moon, when it stopped making an
eclipse with the star behind it, the light from the
star would just drop off, or at least drop off
relatively quickly. But if it has a little moon maybe
trailing behind it, then the light from the star would
go down mostly but not all the way, but then
a little bit of a shadow would remain, and then
the shadow would go away. And that's the kind of

(44:10):
thing you're looking for. Right.

Speaker 2 (44:11):
There's a moment after which the planet is no longer
blocking the star, but the moon might be blocking it
a tiny little bit all by itself, which extends this
transit dip.

Speaker 1 (44:21):
Or maybe the moon isn't like in front of the planet,
and so then first the moon gets out of view
of the star, and then the planet drops out of
the eclipse, and so you see this little shoulder in
the light from.

Speaker 2 (44:32):
The star exactly, and so they see this shoulder and
they can explain it using again a Neptune size moon.
This planet has a Mars like orbit, so it's even
further from its star than the previous one. And the
planet itself is huge. It's five times the massive Jupiter,
so it's a really big planet with a Neptune size
moon candidate. And the only explanation we have for these

(44:55):
shoulders is an exo moon. There's no other explanation other
than like just random noise, you know, maybe it's just
fluctuations in the data. And they've done a statistical calculation
and that seems unlikely to like one part in one
hundred or so, so it's not like smoking gun evidence again,
but it's a pretty nice signature of what could be
a Neptune sized exo moon.

Speaker 1 (45:17):
And we have more than one data point here in
this case.

Speaker 2 (45:19):
Yeah, we have more than one shoulder. They've seen several
transits of Kepler seventeen oh eight.

Speaker 1 (45:25):
And it always has this little shoulder, or would you
expect it to sometimes have a shoulder sometimes not have
its shoulder because the moon is kind of going around
the planet.

Speaker 2 (45:33):
Right exactly, So you expect the shoulder to vary, and
they see it vary and just this way you would
expect for a moon, right, it has the right wiggles
at the right time.

Speaker 1 (45:43):
H Like, if you assume this, this moon, this neptum
sized moon, is going around every month, and you see
it in a monthly way in the orbit of the
planet around the start exactly.

Speaker 2 (45:53):
And in this case they're able to calculate the orbit
of the moon around the planet and has a period
of several days, and so they factor that into their model.
They have this mathematical model that says, here's the star,
here's the planet, here's the moon going around it. When
should we expect to see dips from just the planet,
from the planet plus the moon. From just the moon.
They can use that to predict very precisely the light

(46:14):
curve they expect to see, and it all lines up.
I mean in reality, they've done it in reverse. They've said,
what mathematical model of that solar system would explain the
dips that we see? And the cool thing is that
they can't explain it, and they can only explain it
with a model that includes a moon.

Speaker 1 (46:31):
Pretty cool. Can they tell how far away. This moon
is from its planet, from the shoulders with or the
size of the shoulder. That must be how they're estimating that,
is its neptune size or is it from how the
light dips.

Speaker 2 (46:44):
It's definitely from how the light dips. The period comes
from when those dips happen. So yeah, you can estimate
the volume of that moon and the period of that moon.

Speaker 1 (46:55):
Cool. Well, was that a big deal when they discover
this or is this still something they're confirming this?

Speaker 2 (47:00):
There's definitely something they're confirming. Nobody's like one hundred percent
sure that this is an exomoon. It's like in the
candidate stage, and they're planning to observe more with Hubble
and with James Webb and with other devices. The next
transit of this planet in the star was in March
of this year, and so I hope that they got
some data and they're analyzing it now.

Speaker 1 (47:19):
Yeah, as we speak, it might be confirming this right now.

Speaker 2 (47:23):
And as more data comes in from more cool giants
or more exoplanets, we're going to see more and more
hints of exo moons, until eventually this goes from like
maybe tentative discovery to like we are drowning in exo moons.
They're everywhere. You know, people who get their PhD and
like a single tentative discovery are going to be amazed
when ten years later people are doing their PhDs with

(47:45):
thousands of candidates.

Speaker 1 (47:46):
Oh, man, I guess that's how it went with exoplanets, right,
Like people for work for a long time just to
find one exoplanet, and then as the technology and the
techniques got better, and now they're finding them by the thousands.

Speaker 2 (47:57):
Yeah, exactly. Now people are doing like statistical analysis, you know,
distributions of planet sizes. They're looking at trends in these
planets to try to understand what it means about how
solar systems form. And so right now or at this
very exciting moment, we're on the cusp of being able
to see these exo moons, and we know that as
technology improves in the future, we're going to be able
to ask and answer really interesting questions like how common

(48:21):
is it to have hundreds of moons in a solar system,
or to have moons whose relative size is so big
compared to the planet like ours is.

Speaker 1 (48:29):
I guess that's the big goal, right, is to compare
other solar systems to ours. It's like our most solar
system out there like ours, or is ours weird? And
if it's weird, why is it weird? Right?

Speaker 2 (48:40):
Yeah? And is that weirdness crucial for life or maybe
it hindered life here in our Solar system and made
it less likely? Right? Maybe life is really really common
in the universe and we relate to get started because
we have a weird moon or not enough moons or
too many moons or something. What we know is that
they're going to be surprises. Like when we started discovering exoplanets,
we were surprised by what we found. Our models of

(49:01):
how the Solar System formed have been completely upended by
our discoveries about exoplanets and exo moons. I'm sure will
also have lots of surprises.

Speaker 1 (49:11):
Yeah, Like it was a big surprise how many exoplanets
there are out there, right, especially the ones that are
like Earth.

Speaker 2 (49:16):
Yeah, exactly how many hot jupiters there were. And the
diversity of moons in just our Solar system is crazy, right.
We have moons that were formed with planets, we have
moons that were captured, moons made had a weird stuff,
moons that might have come from collisions. They're probably a
whole other ways to make moons we haven't even thought
of because they don't exist in our solar system. The

(49:36):
diversity of exo moons is going to be really, really wild.
There's going to be some weird stuff out there.

Speaker 1 (49:41):
And moons have a big impact on life itself, right,
Like think about how much of life on Earth is
sort of sync to the lunar calendar.

Speaker 2 (49:48):
Yes, some people speculate that having such a big moon
with its dramatic tides could have had a big impact
on the formation of life here on Earth. People think that,
like in the brackish water between the fresh water and
the salt water, that the sloshing around and the mixing
up of all those chemicals and the primordial soup might
have really helped life form, And so having the moon

(50:09):
there with its big dramatic tides could have been a
big boost to the formation of life. It might be
that it's crucial to have such a big moon. That'd
be really fascinating. Right if we found life in other
solar systems and in every case they had a weirdly
big moon.

Speaker 1 (50:22):
Whoa, we might have the moon to sign for being here.

Speaker 2 (50:26):
Exactly or it might be that mostly life is on moons, right,
that maybe moons are a better place to have life
than actually the surface of the planet. You know, we
think that for example, under the ice in Europa or
inside Io or on Ganymede, there might still be life
in our solar system. So it might be even in
our solar system that it's rare for life to start

(50:48):
on a planet compared to moons.

Speaker 1 (50:51):
Yeah, it might be that life is over the moon.
About having a moon, and that.

Speaker 2 (50:56):
Joke exactly, and people have really fun about how life
can evolve on these moons, using like the planetary magnetic
field as a shield from cosmic rays and being close
to the star but avoiding being tightly locked to the star.
There's all sorts of reasons why life could form on
a moon. And because there are so many more moons

(51:16):
than planets, we think that means even more places for
life to start.

Speaker 1 (51:21):
Right, Right, All the moons harder to have an atmosphere
because they're smaller, are.

Speaker 2 (51:26):
Smaller, so it's harder to have an atmosphere. But you
could have life within those moons, right, You could have
underwater oceans. Most life in the universe might be under
ice crusts.

Speaker 1 (51:37):
Whoa, they might be cooler than us, or more most
certainly they are cooler than us, at least us here
on the podcast.

Speaker 2 (51:44):
They might have no concept of the universe. Right, If
you form in a dark ocean, you can't even access
the sky, Right, you'd have to somehow drill a hole
in that ice and climb out before you even know
that the rest of the universe is there. What a
crazy mind shift that would happen to be.

Speaker 1 (52:00):
Well, there might be like how we thought about the
Earth of the universe before, Right, we thought there was
a ceiling. Basically, they might actually have a ceiling.

Speaker 2 (52:07):
They might literally have a ceiling exactly.

Speaker 1 (52:10):
Well, hopefully they'll blow the roof off with that bit
of science there.

Speaker 2 (52:14):
We're always in awe of everything we discover and always
surprised by what the universe has in store for us.

Speaker 1 (52:19):
Yeah, because I guess scientists are always aiming higher. They're
always getting more and more ambitious. In other words, they're
always shooting for the moon. All right, Well, we hope
you enjoyed that. Thanks for joining us, See you next time.

Speaker 2 (52:40):
Thanks for listening, and remember that Daniel and Jorge explain
the universe is a production of iHeartRadio. We're more podcasts
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