Can we see the surface of exoplanets?

Could we build a telescope that let us see what planets around other stars look like?

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Episode Transcript

Speaker 1 (00:08):
Hey, Daniel, you know those awesome and amazing pictures of
Earth that you see from space. I love those Earth
as the Blue Marble pictures. They are gorgeous. Yeah, but
I think they're also a little bit creepy. Creepy because
it gives you a sense for like how tiny we are,
how insignificant we are in this vast ocean of space. No,
because it sort of makes me feel like, what if
there's something out there taking a picture of us, you know,

(00:30):
like if I step outside in my on camera. Yeah,
what if they're like aliens on other planets watching us
on the surface of the Earth. Well, I guess I
would really worry me. Except today, I don't think I'm
that interesting. I don't know. I bet everything that we
do would be hilarious to aliens live from Earth. It's
Every Night Earth, the live action comedy show. Hi. I'm

(01:09):
or hand Ma cartoonists and the creator of PhD Comics.
Hi I'm Daniel. I'm a particle physicist, and I'm always
wondering if the aliens are watching or hearing or listening
right they could be or or feeling us I don't know,
or sending emails to our podcast. That's right, any one
of those emails you get every week every day could

(01:31):
be from an alien. That's right. I have no idea
who's actually behind those emails. It could be a person,
it could be a clever dog, It could be our
interstellar listeners. Bob from China could actually be Bob from
Alpha Centri. You never know. It could just be their handle.
If he's from Alpha Centauri and he's managed to email us,
I wish he would send us some answers and not

(01:52):
just some questions. Would would that mean? To the pointing,
if you finally meet aliens and all they have is
just more questions, Well, that really just depends on who
meets too. I mean, if they make it here, they
got to know more about physics than we. Well. Anyways,
Welcome to our podcast, Daniel and Jorge Explain the Universe,
a production of I Heart Radio in which we talk

(02:13):
about all the incredible, beautiful, amazing, weird, bonkers phenomena that
make up the universe around us and share with you
our wonder and trying to touch on the wonder that's
inside you, the curiosity to understand the universe and try
we talk about all the amazing things to see from
this little rock that we're sitting on called planet Earth.

(02:33):
And we also like to talk about all the things
we can quite see just yet, but that we may
one day. That's right. The journey of humanity and science
has been one of ever reaching ability to see further
and further into the universe. First we just looked up
with our eyeballs. Then we build telescopes to reveal the
moons of Jupiter and the farthest planets. Then we saw

(02:54):
even further to discover that there were other galaxies out
there in the universe. And now we have an incredible
three D vision of a huge, vast reach of space.
But there are questions that remain, what's out there? Who's
out there? What are they doing? Are they listening to
this podcast? Sorry? Who? Or what is out there? Because
who knows if aliens even go by? Who? Right? What's

(03:15):
their pronoun? Is that your first question? My first question
is about physics. Your first question is what's your pronoun? Well, yeah,
that's kind of the standard these days. That's diplomacy will
be important if we don't want to get eaten before
we even get to ask physics questions I see, or
if we want to choose how we get eaten. You know,
you never know. But we do talk about aliens sometimes

(03:37):
in this podcast, and it's something that you know, we
talked about having skepticism about, and we've talked about whether
it's possible that there are aliens out there. But I
guess one thing we've never really touched on is the
fact that if there are aliens out there, they probably
come from a planet. Yes, a planet, or a moon
or some rocky body. But you know, again, it depends

(03:57):
on sort of how you define aliens. If you define
it to be some kind of life that's similar at
all two hours, then yeah, you'll need some kind of
environment that's similar hours. But you know, you could imagine
aliens living in energy streams inside suns or intergalactic media
on very long time scales. The more science fiction you read,
the more crazy ideas you need to think about. Oh

(04:20):
I see, huh, Well, I guess yeah, I guess I'm
thinking more of like aliens who live on planets. And
so the question is, could we ever take a picture
of these aliens and their planets and what's possible to
see from other planets that are not in our Solar system.
And it's crazy that we even think about this kind
of question, because remember it's only like years ago that

(04:42):
we figured out that there are other planets out there
and that we could detect them, we could like measure
them and prove that they exist. That's like a very
recent discovery. You know, in the nineteen eighties we had
ideas we were pretty sure there were planets in other
solar systems, but we've never actually seen one, and so
it's pretty recent that this is like something we can

(05:03):
grapple with at all. And so now of course we're
getting greedy and we're wondering, like, well, you know, how
well can we see them? Can we zoom in on
these planets? So to the on the podcast, we'll be
asking the question can we see the surface of exo planets?
And run off the bat. I want to clarify something

(05:25):
because I feel like a lot of the coverage of exoplanets,
when they discover a new one, it usually says, you know,
new earthlike planet discovered, and then in the article there's
a picture of a nice ocean world with continents whatever,
and I think people get the impression that that that's
a picture of that planet. But for some reason, space
journalism usually features artists Bologna renditions instead of real data.

(05:49):
So I want you to impact their Daniel and your statement.
First of all, space journalism, man, and what a fun
title to have in your business card from a space journalist. Yeah, exactly,
space reporter. Kudos to those people, But why do they
keep featuring you know, artist's imagination over data. Have nothing
against artists imagination, but it's not a stand in for

(06:10):
actual knowledge. I'll just put in my business card intrepid
space reporter. Why not? But maybe this might not be
a word that everyone who's listening has heard of before.
Exo planets. Does that mean that it's like an X
planet or you know, like a kitchen utensile type of planet.
It just means a planet outside of our Solar system,

(06:31):
that right, That's why we put the word exo in
front of it. It's like outside planets. Yeah, exo just
means in another solar system, and so exo planet just
means a planet around another star. You know, we've seen
in our solar system there are eight or nine planets,
depending on which side of that ridiculous argument you fall.
But other solar systems are really far away three four,

(06:53):
ten thousand light years away, and so the planets around
those stars. Remember, planets are really small all compared to stars,
as the planets around those stars are very difficult to
even detect, not to mention, actually image or like zoom
in on to see what's going on in that neighborhood. Yeah,
and like you said, we up until about twenty thirty

(07:15):
years ago, we only had an idea that there could
be other planets out there, but we didn't really confirm
or really have physical evidence that there exist at other planets.
Like it could have been that every star we've seen
the night sky doesn't have any planets, and we are
the only planets in the universe. That's right. Just like
we don't know whether we're alone in the universe, we
didn't until recently, know whether we were the only planets

(07:37):
in the universe, which is kind of crazy, but you know,
the universe is crazy sometimes, and you don't know if
you're one of a kind, and the reason you're asking
this question is because you're the only one around to
ask it, or if you're one in a trillion. So far,
the trend seems to be the one in a trillion direction.
There are lots of galaxies, there are lots of stars,
and now we know there are lots of planets. But

(07:59):
you can't make as something you can't just you know,
artists imagination your way to answers. You have to actually
figure them out. Yeah, and so now we know that
there are a ton of planets out there, you know,
not just like a few planets out there, but it's
like almost every we know for sure, almost every star
out there has probably a handful of planets, right. Yeah,
And every time we discover one of these planets, I wonder, like, wow,

(08:20):
what does it look like it's going on over there?
And it's a fascinating question. And you know, we only
recently saw close ups of the planets in our solar systems.
We sent these missions just in the last twenty thirty
years to take close up images of Jupiter and Saturn.
And then in the last few years of Pluto, you
know Pluto, until we sent New Horizons image, it was

(08:42):
just like a little fuzzy dot and even the most
powerful telescopes now we know it has that cool heart
shape on it. But this is like a human need
to visualize things, to see them close up. Yeah, And
so the question is if we are ever going to
I don't know study other exoplanets out there in the
galaxy or in the universe, or you know, sort of

(09:03):
get confirmation of what they look like. What will we
need to do, like do we need to send the
satellite to take a picture or could we take a
picture from here? Yeah, it's a fascinating question. I would
love to see these pictures of planets around other stars.
And maybe we'll see like aliens spelling out messages for
us or something s os like with rocks on the beach,

(09:25):
send send more pizza. Maybe that's what the hard in
Pluto is a message from plutoniums right now that we're
totally like, Oh that's cute. It's hard and they're in distress.
Oh man, and here we are making jokes about it. Men,
we are heartless. But anyways, as usual, we were curious

(09:47):
to see how many people you know, sort of about
extra planets and also whether or not we can see
the surface of extra planets, and so Daniel went out
there into the wilds of the internet to ask this question. Yes,
so thank you to everybody do you who volunteered your
time to answer speculative questions online and to hear your
wild speculations on the podcast. If you'd like to participate

(10:09):
in future listener questions, please just shoot us a message
to questions at Daniel and Jorge dot com. So think
about it for a second. Do you think we can
see the surface of other planets in the galaxy. Here's
what people had to say. I don't think we have
any technology right now or to see planets exhort planets
from space. That might depend what you mean by c.

(10:31):
I don't think we can see the surface of exoplants,
and imagine you need to get a spacecraft out there.
I'm not sure. I think they might be too far away,
but I don't think we can actually physically see any
services of exoplanets as I don't think we've got a
telescope that um is anyone near them. Yes, definitely, I

(10:55):
would say no, I don't think we can as far
as I understand, and we can't. We can't really see
extra planets at all. We can just detect them, all right.
Not a lot of optimism here for taking a picture.
Everyone's like, no, only a couple of yeses. Yeah, pretty
much universally shot down because it seems ridiculous, right, Like,

(11:17):
like we said, the planets in our own Solar system
are so far away that it's hard to image. So
how could you possibly imagine taking a picture of the
surface of planets super far away around other stars? It
sounds like ridiculous science picture. Yeah, it's like trying to,
I guess, take a picture of a marble that's across
the world. Maybe I don't know if the scale works out,

(11:37):
but it sounds like that. It's not hard. Yeah, a
marble across the world that's next to a really bright light,
next next to a lighthouse. I've heard that, Yeah, exactly,
And now you want to see, like, yeah, but is
it a blue marble? Is it a green marble? Are
there tiny little bugs walking on the surface of that marble?
People want to know what's the pattern of air molly
kills around that little marble. We want to predict the

(11:59):
weather on other planets, even though we can't even predict
the weather here on Earth. All right, we'll step us
through this, I guess, um, Maybe let's start with the basics,
like how do we know where there are other planets
out there? And how many they are? Like? What do
we know how do we find other planets outside of
our sources? Right? Well, the first thing to understand is
that seeing those other planets directly is really really hard,

(12:21):
which is why this whole like topic is so ambitious
and and maybe ridiculous. And the way that we know
that those planets exist is not by seeing them, right.
Those pictures you see in the science articles are not
pictures of those planets. They're totally made up. Instead, all
we can do is see the effect of those planets
on the stars that they are orbiting. Like, we don't

(12:42):
see anything really directly about the planet. We see how
it impacts the star and sort of in two different ways. Yeah,
it's it's kind of like that listener who said it
kind of depends on what you mean by seeing another planet, right,
Like if we will only see its effects on other things,
is that really count as seeing or not. Yeah, And
we got into that whole rabbit hole when we talked

(13:02):
about the black hole, like are we seeing the black hole?
Are we seeing the gas around the black hole? Etcetera. Well,
in this case, what we're seeing these two different effects
on the star. One is the wobble of the star.
So when a planet orbits a star, it's orbiting because
the star is pulling on it with its gravity. But
there's a reverse effect. Also, the planet is pulling on

(13:24):
the star with its gravity, so the two are sort
of tugging on each other. And of course the planet
is much smaller, so it moves a lot more, but
the star also moves. And if you take really careful
pictures of the star, you can detect this wobble because
it's periodic. Right as the planet goes around, it wobbles steadily.
It's not like a random jiggle. So if you watch

(13:45):
it over a period of time, you can see the
star moving and that tells you how massive the planet is,
whether there's a planet there, and how massive it is. Right,
you measure the wiggle in the star, and you do
it through like the Doppler effect. Right when it wiggles
to words us, then the light shifts a certain color,
and when it's wiggling away from us, it's just another color.

(14:06):
And so it's a physicist astronomers can actually detect that
a little bit of light that comes from that star.
You can actually detect that wiggle, which is amazing, Which
is amazing, right, Like everything that the astronomers are doing
here is sort of aspirational, Like twenty years beforehand, people
would have scoffed like, that's impossible, but now we're doing it.

(14:26):
And that's the kind of thing that motivates you to think, like, well,
what do we think now might be impossible that in
twenty years we'll have figured out and then we'll be
thinking about the next thing. Right, Science and technology moves exponentially,
so it's good to think anyway. So that's the first method.
The second one is the brightness method, and that's if
the planet happens to pass between us and the star,

(14:47):
then it partially blocks the light from that star. It's
like a fly, you know, flying in the front of
a lighthouse. You can detect a very small dip and
the amount of light that comes from the lighthouse. And
again it's periodic. You can see it regularly, so you
build this up over many, many orbits and you can
get evidence that it's there, right, and it's it's kind
of a very specific dip in the light. Right, like

(15:09):
a little fly flying in front of a lighthouse. You
would see the light from the lighthouse sort of like
a fly eclipse almost but only a little bit. You
can see the light sort of dip stay even as
the fly makes it across the lighthouse surface and then
pop back up when the fly leaves the kind of
the brightness of the lighthouse, and so you're looking for

(15:31):
these very specific kind of dips in the light. Right,
that's right. Not every variation in a star's brightness is
due to a planet. You're exactly right. It has to
be very consistent with the orbit of an object around
the star, and it would make that pattern. In fact,
there was that star recently we saw where there was
a very inconsistent dip in the light around the star
and people thought, oh, maybe that's aliens building some huge

(15:54):
mega structure and it's only half finished and they haven't
finished the parking lot on that interstellar mall, and that's
why the light is in this weird way. They just
went straight for the aliens. They're like, there's an unusual variation. Yeah,
and so we've seen this on lots and lots of
planets now. But you know, it requires the planet to
be in the right plane, like the plane of these

(16:16):
solar systems, the plane around which the planets are orbiting
the star is randomly organized in the galaxy, and so
it has to be aligned just right so the planet
actually goes in front of its star. So not every
big planet out there, can we even see with this
brightness method? Right? And and this sort of historical right,
because I think they started detecting planets with the wobble method,

(16:38):
I think, and then they sort of switched to the
brightness method of looking at the dips in the light,
and that with the explosion of EXCE planets really or
the discovery of EXCE planets happened because then we were
able with the Hubble telescope to just like survey a
bunch of stores at the same time and look for
these dips and brightness. Yeah, and now we have dedicated
telescopes just to do this, just to find planets through

(17:02):
the brightness method. So it's much more powerful now that
we have the technology. And now we've seen thousands and
thousands of planets, like we haven't seen them in the
sense we don't have an image of them to resort
to artists if we want to poof up our science
journalism a little bit. But we have evidence that they exist.
We know their mass, and we know they're radius, and
so we know something about them, but we don't have

(17:24):
images of them. We don't know necessarily what they look like.
We sort of I feel like we know that we've
seen their shadow kind of right, We've seen their how
they block the light, and that tells us a lot
about like the mass and the the orbit. We don't
have a picture of a surface yet. Yeah, that's a
great analogy because we know from the shadow that it exists.

(17:45):
It must be there because it's blocking the light. It's
having this impact on the light source. But it's not
the same thing as seeing the object itself. All right, Well,
let's get into the problem of taking a picture of
the surface and whether or not it's even possible. But
first let's take a quick break. All right, we're talking

(18:14):
about taking pictures of exo planets, planets outside of our
solar system, and whether or not those pictures you see
in uh in science fiction or in some news reports
is to be believed. So this is really hard prompt
to actually see the surface. But actually I was just
kind of thinking back, isn't there do we have a

(18:35):
picture sort of of some exo planets orbiting around a
star like I have a memory of some of like
an image of some blobs around a bigger blob, which
is the Sun. Well, the thing that's important to remember though,
is that it's theoretically possible. Like what happens to a
photon which comes off of some exo planet, some planet

(18:56):
really far away. The light from its stars hit it,
and then it's come out into space. And we know
obviously that happens. You can see the Earth from space, right,
it doesn't glow on its own, it's reflecting life from
its son. But think about what happens to a photon
that hits that exoplanet. It flies off into space. There's
nothing that prevents it from getting to Earth. Right, it
can fly from the surface of that planet, carrying information

(19:18):
about the aliens lunch or whatever, and come all the
way to Earth and hit your eyebland. No theoretical problem
to that, Just like to see a marvel halfway across
the world if you you somehow had a good enough
eye exactly. The problem is that you don't get very
many of those photons, right, You get one photon from

(19:41):
that aliens lunch, But because the planet is so far away,
most of the photons go in other directions, and those
photons spread out, and as you get further and further away,
the density of those photons drops like one over the
distance square. I think about the surface of a sphere
that surrounds that. The area of that surface of the
sphere rose like the radius squared, and so by the

(20:02):
time he gets here, you just have very few photons.
So really it's a questions like gathering enough light. The
light is getting here, you just need to gather enough
of it and separate it out from any other light
that might be overpowering it or confusing you. And as
you were saying earlier, there are a very small handful
of these things where we have seen the planet directly.

(20:23):
I mean, we have a few pictures where the planet
is far enough from the star and big enough to
reflect enough light that we can see that it's there.
But that only works for a very few exoplanets when
we've seen thousands of them the other ways, And for
the ones where we can directly image them, it's not
very satisfying. It's not seeing the surface of the exoplanet.

(20:45):
It's just like one pixel. It doesn't tell us if
it's an ocean world or if there are forests or
just dust. We really need a lot more magnification to
see the features, to see the surface of the planet, right,
Because I guess you know, it's kind of like the
picture of Earth from the from the moon. You know,
we can take a picture of the Earth from the moon,
but then you could even go further and technically you

(21:06):
you could still take a picture if you had to
kind of a beg enough zoom lens. Yeah, exactly. And
you can imagine like taking a picture of the Earth
from Pluto right, Like you've seen those pictures of satellites
that are flying out in the outer reach of the
Solar System, the Earth looks like a tiny dot. All
the information is still there when you went outside and
you waved up at the sky. The information from those

(21:26):
photons is still out there in space, but it's spread
out really far, and so the photons density is very low.
So you would need to either gather information for a
long time or a really big lens, like somebody did
the calculation and discovered if you wanted to take the
picture of another planet around another star, you'd need a
telescope that's like a hundred kilometers wide, and you'd need

(21:50):
to gather light for like ten thousand years. Wow. That
would not fit in my iPhone for sure, or my lifespan.
You know that, paul Us When you press that take
the picture button and it actually collects the light and
takes the picture and then you hear that click sound.
Imagine if that pause is ten thousand years, like, all right,
take the picture, smile and hold it. So that's how

(22:14):
much it would take. But you know, I feel like
we have telescopes that like gather one photon at a time.
You know, couldn't we make use of every photon that
comes in and kind of reconstruct a hazy picture. Yeah,
but you know, you could imagine building a telescope that's
a hundred kilometers wide, even if it's not actually physically
a hundred kilometers wide, by assembling different telescopes that are

(22:35):
like around the Earth, etcetera, etcetera. But you still have
to gather light for a very very long time because
there just aren't that many photons. I mean, we're talking
about a very small object that's not even that bright,
and it's really really far away, so the numbers are
really working against you. But in principle, those photons are there.
So if you develop a big enough telescope or run

(22:57):
it for long enough, then hey, maybe it's post So
that's the nexus of the idea. That's the technical challenge
that this problem is facing, right, it's just that it's
really small, and so it's really faint. Yeah, and it's
super far away exactly. All right, Well, then how could
we possibly ever see the surface of these other planets?
You Well, the idea is literally build as big a

(23:20):
telescope as possible, and because that's the only way you
can overcome these tiny numbers is to have a massive telescope.
And you know, we can't build something that's like the
size of the Earth. So the idea is to use
things that are already there. To use the Earth or
the Sun, especially as a lens, because remember, the Sun
is a big ball of stuff, and stuff has gravity,

(23:43):
and gravity bends light, and so a big ball of
stuff can act as a huge lens. And we've seen
this in the sky already. If you google gravitational lensing,
you can see these amazing pictures where we have some
blob of dark matter and in the background. Way mind,
it is a galaxy and the life from that galaxy
is distorted by the dark matter acting as a gravitational lens. Right, Yeah,

(24:08):
we could use the Sun as our zoom lens. Yeah,
is that kind of the except that it's on fire.
Except that it's on fire which you know causes some problems.
Usually that's not what you want in your telescope, but
in this case, usually you don't want it to be
too hot to handle. Yeah. Yeah, And so we're thinking,
if you're gonna build a telescope using some big massive object,
use the biggest thing nearby, and the Sun, by far

(24:31):
is the biggest blob of mass. But you were saying
you need about I guess you need a hundred kilometer
wide lens, but over ten thousand years. I was just wondering, like,
if you can you use you could use the moon
or something. Yeah, the Moon just wouldn't be big enough.
To The idea is to use the Sun because it
gathers a lot of light, Like it's so strong gravitationally

(24:51):
that it's pulling photons nearby and focusing them. And so
you get a factor of a hundred billion magnification if
you use the on is a lens, which is a
pretty big number, right, what was a number again? A
hundred billion, hundred billion, ten to the eleven. Wow, that's
a lot of zeros. It's a lot of zeros for
the X Yeah, and your telescope. And so the idea

(25:14):
is you have your planet which you're on image, which
is really really far away. And then between the planet
and you you put the Sun. So then the Sun
bends a bunch of the photons which are flying towards
our Solar system but which otherwise would not have hit Earth.
Now get all bent together to some focal point, some
focal point on the other side of the Sun where
you can gather all these photons together. So it's like

(25:37):
you're capturing a huge number of photons which otherwise would
have just keep flying apart, and you're bending them together
into one place that you can gather them together. That's
essentially how the magnification works. So you need to put
your camera, your sensor pretty far away from the Sun.
You're saying, way past Pluto, way past Pluto. Yeah, this
thing would be sixty billion else from the Sun. Yeah,

(26:02):
you have the exo planet, which is like light years away,
and then you have the Sun, and then you have
the focal point which is on the other side of
the Sun from the exo planet. But yeah, sixteen times
as far away from the Sun as Pluto. Have we
ever gone out that far? We have? Not? All right, No,
Voyager one is the thing that's gone the furthest the

(26:22):
man made object that's deepest in space, and it's only
gone thirteen billion miles and so this thing would need
to be out there sixty billion miles. And you know,
Voyager one has been going for forty years, so there
are a lot of technical hurdles to making this work.
Just take a picture. Yeah, the artists do it, Daniel,

(26:42):
use your imagination. Sounds cheaper, and they should draw more aliens.
Then if you're gonna let an artist do it, then
let him run wild. But I just love the you know,
the scale of this idea. The Huber is so like,
you know, let's use the sun to take a picture.
I just love it. But how would you I guess
block them. You need to block the light from the
Sun and then gathered the other you like, coming from

(27:03):
around the sun. Yeah, because you can't see the photons
that actually hit the sun, right, the sun is not transparent,
but you're seeing all the photons that sort of skim
the sun. They go near the Sun and then get
bent towards your camera, and your camera is some satellites.
It's like super deep in space, right, But if you
do this, there's a lot of information there in principle,

(27:24):
they've crunched the numbers. You can take a picture of
that planet that's like megapixels for real, for real, every
pixel that you capture in your satellite would be equivalent
to like twenty five square kilometers on the surface of
that planet, which is not a small which is nothing.
It's pretty small. You could see, you know, oceans, you
could see continents. You probably couldn't see aliens spelling out

(27:47):
s os on the beach, and then they're big aliens,
they're really really they've had a lot of pizza. But yeah,
you could see the shape. You can see like, you know,
even maybe meta structures, right, you could see stuff on
the surface easily. Maybe if they have like a massive
space infrastructure, you might even be able to see that.
So that would be incredible. I mean, imagine seeing that picture.

(28:07):
Imagine being those scientists building this technology, pressing the button
and then you know, a few years later you get
the result and you get to actually see this, Like, Wow,
what a moment that would be for humanity. Wow, So
let's do it? Why don't we do? We do it?
Sounds like it doesn't it sounds like you just have
to build build a satellite What's what's the technical or

(28:27):
financial hurdle here? Well, number one is that it will
take a long time to get there, right, So we
spent forty years getting Voyager one out thirteen billion miles,
So we don't want this to happen in a hundred
and sixty years, right. We need to somehow get there faster. Right.
But but Voyager doesn't have like booster rockets or anything,
does it cann't. Don't we have technology now to get

(28:48):
there faster? Yeah, exactly. Voyager is not a race car, right,
We have ways and ideas to make things go faster.
And the idea is, instead of sending one big satellite,
which is sort of hard to power, ending a bunch
of micro satellites, like streams of pearls of satellites, and
each one powered by a solar sail. Solar sail is

(29:08):
not actually like a jet engine of any kind. It
just captures the energy of the Sun's own light and
sales on it. It captures those photons and it uses
that to pull itself along. All right, Well, it sounds
pretty cool, and I say, let's do it, Daniel. Let's
just let me hop on the phone here with NASA
and I'll let him know I approved this plan. That's

(29:31):
what they've been waiting for. Absolutely. But let's talk about
maybe when we would actually see in these other planets
if we ever took a picture of him. But first
let's take a quick break, all right, Daniel, So you

(29:56):
have a plan for taking pictures of planets outside of
the galaxy, and people have crunched the numbers and it
is kind of possible if you put a satellite out
past way past Pluto, you could use our son as
the lens and actually take like high resolution pictures of
planets in other stars. Yeah, yeah, exactly. What's the hurdle here.
The hurdle is really just making it work and getting

(30:18):
the money. We think we know how to do it.
There's just a lot of technical issues to overcome. And
this is something that NASA is actually supportive of. This
is not just like crazy bonkers idea out there on
the internet, you know, in some Reddit thread. This is
a proposal that's into NASA, that's moving along the stages
that could actually be approved, and they're taking these challenges seriously.

(30:39):
And the challenges are basically like how to get out
there quickly, how to point this thing accurately enough. How
to build a big enough satellite because the image is
going to be still really huge and you want to
sample at night. How to control this thing when it's
really far away. Also, how to pick which planet to
look at, because one issue is you build this thing,
you send it to one place in space. You can

(31:01):
only look at one planet. You can't like, turn this
thing to look at a totally new planet. We can't
turn it. We can't turn it because the location of
an image for an extra planet is in a specific
spot in space. And then if you want to image
another extra planet, you have to go to where that
image is. Right, the image is always on the other
side of the sun. You can't move the sun, so

(31:22):
you have to move where your camera is, and those
locations are really really far apart, and so basically you
have to pick before you go. You just send your
camera out there and you have a telescope dedicated to
one planet. Really, I would think that there are so
many stars out there that we would have our thousands
of exo planets that we know about and could focus on.

(31:44):
Wouldn't the days be littered with images of these planets? Yeah,
but you have to be really precise about where you're imaging,
and so in order to change the target that you're
looking at, you need to be able to move laterally.
And most of these spacecraft that we're sending are only
gonna be able to move radially, like we're sending them
out there, and they're actually gonna be traveling outwards as
they take an image. They're not going to stop. It's

(32:05):
not like they get out there to the focal point
and then they just stop. They get out there, they
start taking images when they get to the focal point,
but it's more actually a focal line, and as you
move along that line you get further from the sun,
you take pictures of different parts of the planet. So
you have to integrate over many years as you move
further and further away. So it's it's like a one

(32:26):
shot deal. What can we build a spacecraft that you know,
stands still and takes the picture. Yeah, that would be
much more complicated. You'd have to be able to stop.
These things are gonna be moving really really fast by
the time they get out there. To get out there
at a reasonable amount of time, you need to accelerate
to a very high speed, and then to stop requires
as much energy, but you no longer have access to,

(32:48):
you know, the solar energy in order to slow down,
and we only know how to build solar sales to
sort of speed up slowing down as a whole different problem.
You need a solar parachute or something solar break Yeah,
all right, Yeah, you were telling me that these things
would need to be would take twenty five years to
get there, and they would need to be three times

(33:08):
more accurate than Hubble, which is pretty kind of our
state of the art kind of Yeah, exactly, because you
have to point very precisely, like the light is going
to be coming from that planet bending around the Sun,
making this Einstein ring. It gets distributed all the way
around the Sun, and then you have to point it
exactly the right spot in the Einstein Ring. And even still,

(33:29):
even though you have all this magnification from the Sun,
you still have to spend a lot of time building
up the image. You want to keep your camera pointed
exactly essentially the same target pixel for weeks and weeks
and weeks or months in order to gather in a
photon to actually see what's there. Does it sounding less
appealing by the by the minute, here Daniel I'm like,

(33:50):
how much do I want to see a picture of
another planet? What do you mean it's just engineering trouble.
You want to? You want to? I mean I want
to enough for both of us, trust me. But if
we pick one planet and we send a satellite and
it's it's a boring planet, that's a real concern. You know.
If we have four thousand plants to pick from, it
could be like a hundred of them have amazing superstructures

(34:11):
an alien life on them, and we just pick one
that's like dust and rubble and it's like yawn, And
that was a hundred billion dollars and thirty years of work.
Let's send four thousand satellites. Then that's obviously the solution.
That is a great idea. I'm loving the ideas. Can
I cot People take pictures these days with their phone?
You know, they don't just take one picture. They go

(34:31):
like and then later and you pick the one where
nobody's blinking. Yeah, I'm pretty sure they do that because
those pictures are free, and if each one costs a
hundred billion dollars, people might press that button with a
little more thought. Yeah, they might think about it a
little bit more, for sure. Yeah, and you know, we
think we know how to solve this problem, but there
are still a lot of technical issues, like we are

(34:52):
seeing faint photons coming through the corona of the Sun essentially,
and you have to pick out these photons for that corona.
It's not an easy job to increase the signal to
noise ratio to the point and this is actually gonna
be doable. You need a pretty good set of sunglasses
or pretty solid thumb to put in front of the sun. Yeah, absolutely,
you do. In addition, this thing has to basically control itself.

(35:15):
It's gonna be so far away from the Earth that
we can't like send messages. You can't drive this thing
with a joystick. It's it's gonna take four days for
messages from Earth to get to our camera that's out
there in the solar focal point. And so basically has
to organize itself. Has to be basically AI power. My goodness,

(35:35):
the first AI photographer, that's right. How do we know
it's not just doing deep fakes and sending us images.
It's made up on the Internet. That's why the alien
could gain a sentience, and then it'd be like this
is too much work. If I send them a born planet.
They're gonna fire me. I'll just deep take a fun,
cool planet with aliens in it, yep, and then we'll

(35:57):
get all excited. We'll send an interstellar ship towards the
direction of that planet, and then only in a thousand
years what we discovered that we were lied to. That
sounds like an awesome plot for a science or canel
a little bit of a letdown at the end, but
it sounds interesting. But you're right. We could take a
picture of this planet and we could discover nothing, or
it could be fascinating, or it could be like confusing

(36:19):
and fuzzy. Right, we're going to see a picture of
this planet. We're not going to necessarily be able to
tell what we want. We're not going to see literal
aliens walking around on the surface at square kilometers per pixel.
We might just be able to make out fuzzy details.
I mean, remember what it was like when we first
got pictures of the surface of Mars from Earth. People
thought they saw faces and canals, and there's lots of excitement,

(36:42):
of course, all of which was bubb kiss Like they
did see a face, didn't they Yeah, they saw a face,
but it was just a mountain shape where they happened
to have a shadow that looked like a face right now,
I mean, isn't there a big smiley face on the
surface of Mars or I'm not sure if that was
an artist in a shion our actual data? All right, Well, um,
it sounds like it's going to be pretty difficult to

(37:04):
get a picture. Can we send a satellite to another planet,
Daniel and take a picture closer? We certainly could, and
that would be awesome, but it would take a zillion
years to get this. I guess what's the closest exo
planet that we know about. Yeah, the closest exo planets are,
you know, in the five to ten light year distance,
And and that's pretty far away. You know, if you

(37:26):
built Hubble, for example, and send it that far away,
you couldn't send it really high speeds very easily. You
can't tolerate a lot of acceleration, so it would take
a long time to get there and then take those
pictures and send them back. I mean, Andy, that also
sounds like a good idea. Let's do both, Let's do
it all, Let's do it all. I mean, we're spending
trillions on everything these days, so why not a hundred
billion to see pictures of ailure. Yeah, well, it would

(37:48):
take maybe like a couple of dozen years, you think,
or hundreds of years to go and take a picture
of another planet. How long it takes to get out
there depends a lot on the propulsion you use, and
for your very expensive import and telescope, you probably want
gentle acceleration, but you also wanted to get going pretty fast.
So I think the best option is to build like
a solar sale the size of Texas, and that might

(38:11):
be able to get your telescope up to like ten
of the speed of light, and it would still take like,
you know, fifty two hundred years to get there. But hey, yeah,
that sounds like a great You're like, this one is
Daniel approved. Let me start a ready tread here too,
to tell me, I only have enthusiasm. I have no responsibility,

(38:31):
and that's why I have no authority also to make
these decisions. Somehow the two are linked. I'm not quite
sure why exactly exactly, No, but I think it's a
fascinating question. I think it's sort of the next generation,
you know, the next frontier and understanding what's out there
in the universe is to get these close up pictures
of what's going on. And so I'm looking forward to it.

(38:53):
I'm hoping that this kind of thing happens and that
we press the button and we see the picture, and
that I get to see the picture a literal sure,
not an artist impression what's happening on these planers, right,
because you know, it feels like a basic human curiosity,
you know, to see pictures, to see like actual photographs
of something, not just like the blip in the light
or you know, the gravitational effects or something. You know,

(39:16):
we there's something about our human brain that we just
we need to see it. Yeah, And you know, it
makes you wonder if there are alien civilizations out there
that already have this technology. If we're on the verge
of it and we've only been around for a few
tens of thousands of years as a civilization, certainly somebody
else has figured this out. And somebody else may have
even put a picture of Earth up on their walls

(39:37):
someway out there in the unit, and then tragically those
wipe left. They're like, look at this blue planet. It
looks kind of boring. Or let's keep going, yeah, or
maybe that's good, right, Like this blue planet doesn't look delicious.
Let's keep on, Let's keep on. What do you want
for lunch today? You guys feeling like Earth or you know,

(39:57):
some other planet? That's right. Everybody look as unappealing as possible.
I think we're we're on our way there day. That's right.
I do my best not to look delicious every day.
All right, Well, we hope you enjoyed that, and then
hope you look at the night sky or look at
the sky out there and wonder what do other planets
look like? Do they look like Earth or Mars, or

(40:19):
Venus or Jupiter or maybe something completely different? That's right.
And remember that the technologies the capabilities that we are
scoffing at today are things that scientists and engineers are
imagining and working on to make possible for tomorrow and
humanity's ability to see what's out there in the universe,
to understand what's in this crazy, bonkers cosmos, and to

(40:41):
peel back layers of reality to penetrate what's really happening
seems unlimitable, and so hopefully our children and our children's
children will know so much more about the way the
universe actually looks yeah, and they won't have to use
their imagination. That's right, and maybe it'll even be cheap
by then. Will be an app for that in five years, right,

(41:03):
that's right. You can swipe left, right, up and down
see any planet you like. Well, thanks for joining us,
see you next time. Thanks for listening, and remember that
Daniel and Jorge Explain the Universe is a production of
I heart Radio. For more podcast from my heart Radio,

(41:26):
visit the i heart Radio app, Apple Podcasts, or wherever
you listen to your favorite shows.