August 8, 2019 • 40 mins
Put on your stretchy pants and join Daniel and Jorge while they take you a guided cruise of the exoplanets.
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Speaker 1 (00:08):
Hey, I hear that you like taking cruises. I just
recently took my first one last last week. Well, let
me ask you a question. Before you get on the cruise.
Do you do like a lot of research to figure
out where the cruise is going to stop? Or you
just sort of trust them to take you to nice places? Well,
I think the whole point of a cruise is that
you don't have to do any research or worry about anything. Oh,
(00:30):
it's about physical and mental laziness. You just get on
and you gain weight. That's the whole point. Do they
charge you per pound or per pound gain? Exactly? The way?
How much of it stays with you is how much
they charge you. But do you like just hanging out
on the boat or do you like that they take
you to different places to explore? Well, I've only done
it once and it was sort of a nice mix
(00:52):
of both. Like you spend some time at sea just
hanging out on the boat, and you spend some time
like disembarking and exploring some new different country. And what
do you look for when you're embarking and exploring a
new country? Bananas? That's bad. That's about all that I need,
all right? Well, In that case, I have got a
cruise to sell. You do tell how much does it cost? Well,
(01:14):
would you buy a ticket on a cruise that stops
at all sorts of alien planets outside our Solar system?
It depends. I guess you know how how good is
the buffet? It doesn't really like dehydrated food, astern not food,
I don't know. It turns out it's mostly bananas, right,
Dehydrated bananas do are harder to slip on in s
(01:34):
g Alright, the listeners, there is a seat available for
our cruise to exoplanets. Hi. I'm or handmade cartoonists and
(01:57):
the creator of PhD comics. I'm Daniel. I'm a particle
physicist and I might be the only person on the
planet who doesn't like taking cruises. Have you been on
a cruise, Daniel? I have been on exactly one cruise.
Did not like it. Not a fan, No, to me.
I'm not a big fan of hotels, kind of a homebody,
and to me, a cruise is sort of like a
floating hotel you're trapped in. Well, anyways, we hope you
(02:19):
that you are listening to this on a cruise or
maybe not. Uh, and so welcome to our podcast Daniel
and Jorge Explain the Universe, a production of I Heart
Radio in which we cruise around the universe finding weird
and interesting stuff to dig up and explain to you
to download into your brain. Um, the buffet of fascinating physics,
(02:39):
that's right. So you just have to hop on board,
sit back, and relax, and and cruise around with us
through the furthest reaches of human knowledge. That's right. Today's
efforts to fatten up your cerebral cortex. We are going
to be zooming around the universe and wondering what does
it look like out there? So today on the podcast,
(03:01):
we'll be talking about water planets outside of our Solar system,
Like where are they? What do we know about other
planets that are not the ones that are right immediately
next to us? And this is sort of the first
question I thought about when I heard about the discovery
(03:22):
of planets around other solar systems, Because what's the point
of finding these planets if you can't imagine going there,
if you can't like ever go see them and swimming
those alien oceans? And so I wondered, like, what are
these planets like? Are they like Earth? Or they like
sad or they like Jupiter. Are they like something totally
weird and different? Right, because we know what the planets
(03:43):
are like in our Solar system, right, There's some there
are just big balls of gas. There are some there
are just big rocks. And so the question is is
that kind of the model for the rest of the
universe or our planets maybe totally different outside of our
Solar system. And that's such an citing moment in science
when we first get to sort of crack open that
box and learn whether the things we've known for hundreds
(04:06):
of years are typical, like representative, like the rest of
the universe is like this, or whether we've been misled
into thinking that most solar systems are like ours, when
in fact ours is an anomaly. We never know until
we go and explore those other solar systems, until we
actually get the data. So those moments in science, when
we get to ask nature of these questions and learn
(04:27):
for the first time in human history what the sort
of larger cosmic context is. That's the kind of stuff
that gets me really excited, because you know, if you
watch science fiction movies or Star Trek or Star Wars,
you would think that every other planet in the universe
looks a lot like the Earth, maybe because most of
them are actually filmed on Earth. Wait, what a surprising
number of planets look like southern California, so nondescript desert
(04:51):
outside of the Angus. That's right, exactly. But you know,
you've got to give people credit, Like, all we can
do is imagine sort of what we know and extrap
a little little bit from there. It's really hard to
imagine something totally new, something totally alien, something outside of
our experience. That takes unfathomable creativity, really, and so what
we need is more data. We need to go out
(05:12):
there and see what are these planets like? And uh
and so I'm as an avid fan of science fiction,
I'm desperate for this data. I'm really curious to know
what do other planets and around other stars actually look like. Yeah,
because because all those movies and TV shows could be right, right,
you know, there could be a lot of planets out
there that look just like the Earth, you know, blue
and green and with deserts and um humanoid blue people.
(05:38):
That's right, It certainly could be. It could be that
planets or of a few varieties you know, rocky with
some water around them, um, gas, giants, etcetera. Or could
be that there's a whole other class of planet that
we've never even imagined before, right, that we've never seen
just because there isn't one example in these eight planets
around our Solar system. But you know, there's billions of
(05:58):
planets in the universe. So the odds that we have
an example of every kind of planet in these eight
seem pretty probable right there. It's got to be some
crazy surprises out there. Yeah, we only have eight data points,
you know, eight examples. Yeah, imagine you have what a
planet can be like. Yeah, imagine you have a bag
of fifty billion marbles and you get to draw eight
(06:19):
marbles out and from that extrapolate what the other fifty
billion look like, right, I mean, that's a pretty small
lever armed to make some guesses or maybe not just
what they're like, but how often earthlike planets happen out there?
You know, it's super rare to be a blue and
green and beautiful with them jungles and desserts, or is
(06:40):
it pretty common? That's right? And you can take this
question from from the sort of like fantastical creative side,
like what do they look like. And you can take
it from the practical side, like you were saying, like,
could we live on any of those or is it
worth sending colony ships to any of these other planets
to sort of expand the human diaspora. That's a great question.
And the mind blowing thing is that up until maybe
(07:00):
what like twenty years ago, twenty five years ago, we
didn't really have confirmation or no for sure that there
were other planets. Like thirty years ago, for all we know,
we could have been the only planets in the universe.
That's right. We had no evidence, We had no evidence
for other planets, and and it's because it's really hard
to see planets around other stars, and so we thought
(07:20):
it pretty unlikely that there were no planets around any
other stars. But we didn't actually know until thirty years ago.
And since then the field is taken off and we've
we've learned about a lot about these planets, and now
we're even at the point we're starting to get some
glimpses as to what they might look like. It's a
fascinating moment in astronomy. Yeah, all right, well let's get
(07:41):
into it. And and so there's a technical term Daniel, Right,
for planets that are outside of our solar system. Right,
there's a science term for them, that's right. Were you
on the committee that made this name, by the way,
I was not. I would have um, I should have been. Well,
they're they're officially called exo planets, which always makes me
think of like you know, exo skelet teens or you know,
(08:02):
like like an armor or like you know bugs. Well,
that's exactly right, Like exo exo skeleton is a skeleton
on the outside. So to me, XO means like outside
like a way, So exo planets are like planets outside
our solar system. To me, it makes a lot of sense. Also,
it launched a whole set of names of new fields,
you know, like exo planetology, exo meteorology, extro exo biology. Right,
(08:29):
these are some extra exo paleontology. You can just add
exo to your scientific field and all of a sudden
it's much cooler. EXO psychology. Yeah, exo cartoonists, exo economist,
XO podcasts. Technically our podcast is XO solar system. And
(08:51):
what in a couple of years, the signal will probably
leave the solar system. Yeah, yeah, exactly Um, are these
podcast waves and they are broadcast over the radio will
leave the solar system. You're right, Oh my gosh, I'm
I'm having a moment here realizing that our words are
transmitting through the cosmos. You're freaking out all of a sudden,
I have stage fright because the stage has just grown dramatically.
(09:14):
All right, well, let's the question is then, what are
these What do we know about these planets that are
outside of our solar system? So we have a pretty
good idea of the ones in our solar system. Right,
there's eight. There used to be nine. Now they're eight
because some people did not like Pluto, and we know
that there are some of them are gassing somewhere. There
are big somewhere. The are hot and small and rocky,
(09:36):
but we we really don't um had any idea what
they would look like outside of our solar system. Right,
you want to hear my favorite Pluto planet um controversy story. Yeah,
for sure. Um. Well, there's a fantastic planetarium in Chicago. Favorite,
so you have several favorite. Um, there's this fantastic planetarium
(09:56):
outside Chicago in Chicago, downtown Chicago, the Adler Planetarium, And
it was built before Pluto was discovered. So it's an old,
old building and so they have eight planets on there.
And you know, then Pluto was discovered, and for decades
it was sort of out of date. They're like, should
we add Pluto? Should we get around to it? You know,
Chicago bureaucracy moved slowly, and then Pluto was demoted and
(10:19):
so they didn't need to add it anymore, and all
of a sudden it was back up to date without
doing anything. So I guess the lesson is, you know,
just wait and maybe you know what you have is
going to be correct again. Science sort of oscillates. Lesson
is if you procrastinate, you might save you a lot
of work there exactly. But I was wondering what do
people think about what do they imagine when you talk
(10:42):
about planets around other stars? And so I went around
campus UC Irvine and asked people if they thought that
planets around other stars sort of looked like our planets
or look totally different or something else. Yeah, so close
your eyes. Maybe not if you're driving, but if you're
not driving, um and you're in a cruisers something, close
your eyes and try to imagine and another planet outside
(11:03):
of a different star out there in the universe and
try to imagine what that planet might be like. Here's
what people had to say. When you think about planets
in other solar systems, how do you imagine they look like?
Do they look like the Earth or like Jupiter or
something totally new and weird? Maybe maybe not. I mean
every planet has a like different I guess, so probably
(11:25):
like that too for the most part. I imagine sort
of gas giants, dead rocks like for like, most planets
are not life sustaining, as I tend to imagine them.
They are very rough, uh and very different, but there's
no life. The condition would be totally different. I guess
they'd all be different, but it's going to be different
(11:47):
between depending on what another in the Goldilog zone or not,
how much light gravity that acts upon the planet. So
I'm honestly not really certain what's going to end up
around extra planets because it just depends significantly on the
different factors. The ones that we've most discovered, like massive
(12:09):
like Jupiter, gas use and also close to the Sun. Uh,
most of them are not like Earth. I know, We've
also found some that are comparable, So I imagine most
of them would be gaseous and pretty uninhabitable. I know
that people have speculation that there are you know, habitable
planets out there, um, but there are a lot of
(12:31):
them that they are different, you know, something that might
I don't know, rain diamonds or I don't know my
thing raining in there. I don't know, raining diamond sounds
pretty dangerous. I feel like they might be similar, but
maybe it depends on the placement of the planets, like
in the Solar System or like in our galaxy in
(12:52):
gerl I don't know. Alright, some pretty eclectic answers there,
you know, I think a lot of people were. I
saw people on their faces sort of scratching their heads
and wondering, uh, you know, and wondering what they would
be like, and trying to be creative. But you know,
in the end, we don't have like a really great
well of inspiration outside of our own Solar System, So
(13:12):
I think, you know, before we get really creative answers,
like I was saying, before, we're gonna need some data
to sort of spark the creativity. I like the person
we said, is it's either gas or solid? What about
an all liquid planet? Right? A planet that's just like
a blow, like a drop in space. That would be
pretty cool. Is that possible? Can you have a totally
(13:33):
liquid planet? I don't think so. I think at the
core it would be so dense that it would have
to solidify. But you know, proved me wrong. Universe. Let's
discover an all liquid planet that would be awesome with
fish swimming like all the way through it. That would
be really cool. Isn't there a moon in Jupiter? We
talked about this, right Europa. Isn't it mostly like a
giant ocean? Well, there's kind of like a big proplet.
(13:56):
There is a really huge ocean with more water ear
than he's on Earth. But we also think that there's
a solid core, so it's it's not just a liquid
drop in space. That would be pretty awesome. Somebody out
there find me the science fiction story. Somebody must have
written about an all liquid planet. You could call it
water World. Oh wait, that's been done. That's got to
(14:20):
be successful. That that name just screams commercial success. I
can see it already, all right, so um so, but
some people seem skeptical that there would be life in it. Yeah, exactly, Um,
but you know, we don't know. Um. I like the
person that said that maybe other planets on other planets
that have really weird weather, like raining diamonds. That sounds
pretty cool to me. Is that possible? That's possible, right,
(14:42):
I suppose it's possible. I mean, I don't know how
you form diamonds in the atmosphere, but you know, hey,
there's a lot of worlds out there, so there's room
for everything. That sounds like a rap video. You need
a diamond umbrella program. It does sound like a rap video.
That's awesome, So give us the rap lyrics that involves
raining guaments. Go ahead, can your freestyle? I probably could,
(15:08):
but right now I just have Old Town Road in
my head because my kids keep listening to it over
and over. So today you thought it'd be cool, You're
gonna take us on a tour, on a cruise of
all all of the different planets that we know about
that are outside of our solar system, right, I mean,
not all of them, but some of the most interesting ones. Yeah,
because by now we have done a lot of work,
(15:30):
and we have amazing satellites and teams of astronomers figuring
out where those worlds are, counting them, trying to measure
quantities and qualities about them, and we're getting more and
more sort of images about these planets, not direct images yet,
but information about what these planets might look like. And
there are some weird ones already, you know, we're just
scraping the surface, and so I thought it'd be really
(15:50):
cool to sort of get a tour of the weirdest,
most interesting planets that we found so far, and just
to give people a context. Um, we know that there
are probably billions of planets out there, but the ones
that we've sort of detected and and there are definitely there,
that's more than like the thousands, right, that's right. Yeah,
we we speculate that every star has several planets because
(16:13):
so far, um, you know, every star we've looked at,
we've seen planets. But you're right. In terms of direct discoveries,
we found just over four thousand planets in just over
three thousand solar systems, and that number just keeps going
up because we have these amazing telescopes that are very
efficient down now. So that number is as of July one,
(16:33):
two thousand nineteen, we have found more than four thousand
planets and other solar systems, a huge number. And that's
just the beginning, right, because we know there are billions
of them in our galaxies and other galaxies, right, absolutely,
And the next a few decades that number will explode
and we'll be up in the thousands and thousands and millions.
But you're right, there are billions of planets just in
(16:54):
our galaxy. And maybe what's really cool is that we
don't just know these days that the planets are there.
We can't sort of we don't have photographs of them,
of them, but we know we seem to be finding
on more and more about these planets through really like
cool and clever physics and clever observations, right, that's right.
The first things we figure out about a planet are
sort of how fast it's orbiting around the star, because
(17:17):
either we see it's like gravitational effect on the star.
We see tugging the star back and forth. And based
on that we can tell how often it goes around
or maybe sometimes they pass in front of the star
so they block the life from the star. Those the
two main methods, and those methods tell us something about
the orbit, right, how fast is it going around? And
also how much mass is there in the planet, right,
(17:40):
And so that's already a lot of information like how
far is it from the Sun that we can know that,
how much solar radiation is there because we know how
bright the star is, what is the orbit of it.
So already we have a lot of information just from
the indirect measurements, just from discovering that it's there, tells
you how big it is, you know, right, like if
you were on that planet, how short the days would be, right, yeah,
(18:02):
exactly years, exactly and um. And now we're starting to
do even more clever stuff, like we can we can
see how the light from the star passes through the
atmosphere of that planet, right, So sort of like looking
at a sunset on another planet. Right, you know how
when the sun sets over the Earth, the light passes
(18:22):
through a lot of atmosphere and it looks red because
it's passed through so much air. We talked about on
another podcast. You know why the sunset looks red because
of the qualities of the atmosphere tend to bounce away
the blue light and that's also why the sky is blue.
But we can do that on other planets. We can
see suns on other solar systems setting over planets on
(18:43):
their in their solar system. And we can see how
the light changes, and that tells us something about the
atmosphere on those planets, like if the the color changes
or something like that. Right, yeah, I can tell you
what kind of gases in there? Is their water vapor
in there? Right? Is there me thing in there? What's
the atmosphere composition of those planets? Is there an atmosphere
(19:04):
at all? First of all? And if so, what's in it?
And I've heard that you can even sort of tell
the weather a little bit, like from the delay between
the when the light gets blocked or the temperature gets
um changes, you can sort of tell if there's something
swirling in that atmosphere. Not just if there's an atmosphere,
but just like how how much it swirls around inside
(19:25):
of that planet. I know, it's crazy, right, We're measuring
the velocity of gases around other planets, around other stars
that are light years away. I mean, it's like science fiction.
If you suggested this thirty years ago, people would say
that's impossible, right, But now we're doing it, people are
writing papers about it. We're like actually learning facts about
these things. So extrapolate like thirty years from now, you know,
(19:47):
we're gonna have like Google Earth around all these planets basically,
and so far that's all without even taking a picture
of them, right, Like, it's just all from like counting
photons that come and hit the smallest little sensors in
our telescopes. Yeah, because actually and that's sort of a picture. Um.
The other cool way that they learn about what's sort
of on the planet is that they take the picture
(20:08):
of the star when the planet is in front of
the star, and then they subtract the star and they
see what's left and they try to find those photons
that came just from the planet, not from the star itself.
And that's really hard to do because you're talking about
a really little object in front of a really bright
object really far away. But it gives you a sense
(20:28):
of what light is coming from that planet, and that
gives you a sense of like what color is that planet,
what gases are on that planet, because remember every gas
amidst light of different frequencies, and so it tells you
sort of what the composition of that is. So we
have two ways to figure out not just like where
this where this planet is and how fast it's moving
around that star, but what's on that planet? What does
(20:50):
it look like. All right, so that's sort of how
we can see other planets and how many there are
out there, and so let's let's um, let's set sail, Daniel,
Let's go explore the universe visit other planets. But first
let's take a quick break. All right, I know, I
(21:16):
have my cruise pass, I've got my I've losen my
pants a little bit to make room for the buffet.
We are now ready to set sail on this extra
solar cruise to other planets. All right, Well, I thought
it'd be fun to start with the closest planet, right
because we're gonna leave the Earth and they are first
stop leaving Solar System to Yeah, we'll leave a Solar system.
(21:39):
Our first stop is Proximus Centauri. It's a star, and
this planet that's orbiting Proximus Centauri, it's called Proximus Centauri B.
And let's be because it's the second planet they found there,
Like they really need you on this naming committee because
they're finding so many planets, they're just like running out
of name so they just like have a recipe for mening.
I think is a he's a good name. Why not?
(22:02):
He is a good name? I don't know. We'll have
to ask the citizens when we get there. But it's
four point two light years from Earth, which is pretty close.
I feel it's pretty close in the scale of the galaxy, right,
the galaxy is like a hundred thousand light years across,
So that's the closest planet to us. I mean it's
like like in four point two years, this podcast will
(22:23):
have arrived at that planet. Yeah, and so in eight
point four years we should expect a bunch of good
questions or people complaining about how we name their their planet. Right,
But no, I mean it's sort of reachable maybe, right.
I mean, I know we can't go at the speed
of light, but you know we can if we go
as fast as we can, we might get there within
a lifetime. No, exactly, it's totally reachable. And you know,
(22:43):
we could even send something there that could arrive and
send us information within a lifetime. Right. You know, we
build a solar sale, we attach a little thing to it.
The thing could reasonably get up to maybe a half
the speed of light, taking maybe ten years to get there,
five years to send data back. So you're talking about
a fifteen year project lifetime to maybe get like pictures
(23:04):
of Proximus Centauri. So yeah, it's not that far away
compared to the other planets we're gonna talk about, but
it's also not that nice a place to be. If
you ask me, all right, what do we know about
this planet B. Well, we know that it's very close
to its star, right, and so we we call this
thing the A U. The astronomical unit is the Earth
(23:24):
from is the distance from the Earth to the Sun,
so it's useful metric. And this Proximus Centauri B is
only zero point zero five a U, so it's twenty
times closer to its star than the Earth is to
the Sun. So if you're standing on it, the Sun
would look twenty or more times bigger in the sky.
And also it goes around that star and only eleven
(23:47):
point two earth days, so it's like it's zipping around.
It's a hot little planet zipping around the star in
a hurry. So you know, if you're in for a
beach vacation you want a lot of rays, then yeah,
I guess it's a good place to stop first on
our cruise. That that's why it's called planet B and
burn and burning off. But all the bananas are burnt
(24:08):
also because that's probably too much sun even for bananas. So,
but that's the planet B. What about planet A and C?
And does it have any other planets in its neighborhood?
They think that there might be another planet, and they
call this planet wait for it, see right? What? Yeah?
Exactly why they didn't call the first one A that's
(24:30):
beyond my technical knowledge, all right, Um, So that's that's
the first stop in our cruise. That's the closest one, right,
that's right Fort Lauderdale, that's right exactly. Um. Now, the
next planet on our tour is the smallest planet that
has ever been found outside our solar system. And I
(24:51):
have no idea how to pronounce this planet is d
r a U g r. It sounds like maybe a
klingon world. What do you think? How do you think
that's pronounced? I think that's it's like a lord of
the rings underworld beast or something drog drog um. Well,
this planet is so small as only twice as big
as our moon, and we detected it. We can tell
(25:11):
where it is. Yeah, exactly, It's amazing that's such a
small planet can even be detected, right, Um, And this
one is two thousand, three hundred light years away. It's
in the Virgo constellation. And the other really crazy thing
about it is that it's not orbiting like a normal star.
It's orbiting a pulsar, and a pulsar is a pulsar
is one of these stars that emits that that periodically
(25:34):
emits a huge amount of radiation. Right, it pulses. That's
an amazing feed of detection, right that we can tell
so far away such a small thing. Yeah, it really
is amazing. And it also wouldn't be a great place
to live because you don't want to be living near
your pulsar. I mean, this is basically a neutron star
with a huge magnetic field lasting radiation. Uh so not
(25:55):
a cozy place. So far. I'm doing a pretty terrible
job of advertising food something this cruise. So far, this
cruise doesn't make me want to get off the boat. Yeah,
zero star is so far in the help for this cruise. Alright.
So the next star we're gonna look at has a
terrible name. It's but it's the biggest, the biggest planet
that has ever been discovered. It's called Hr sixty two
(26:18):
B and it is thirty times the size of Jupiter.
How do you pronounce that one? Hot in the original
cling on the mass of thirty jupiters or the size
of thirty jupiters. It's the size of No, sorry, you're right,
it's the mass of thirty jupiters. Yeah, exactly. And so
take Jupiter, which is already like, you know, what, hundred
(26:38):
times the massive Earth and multiply by thirty, Like this
is a ginormous planet. But but it's not super far away.
It's kind of closed, right, a hundred light years. Yeah,
it's a hundred ten light years from Earth, and so
it's you know, also potentially reachable. But it's sort of interesting,
like how big can a planet get? This one is
really on the verge of the maximum size for a planet,
(27:00):
because any bigger and the gravitational force will be so
strong that it will essentially turn into a star. So
this jew this is like as big as a planet
can get before it ignites and becomes a star. What
else do we know about it? Is it like a
gas like Jupiter? Or we just know sort of the
mass of it and where it is. That's all we
know about that one so far. You know, a lot
(27:20):
of these planets we you know, some of these techniques
work better on some planets than others, and so we
don't always get to get to see like the atmosphere
of these planets. Um. And that's also all these atmospheric
techniques that we talked about that are so amazing, these
are pretty new and they require some fancy technology. So
we don't have that information about all of the stars
so far. But that maybe gives us a kind of
(27:40):
a range right of planets out there in the universe,
Like they can go as small as twice as high
as on the Moon, and they can go as big
as dirty times Jupiter. Yeah, exactly. Um. And at first
people thought, oh, maybe this is a star, you know,
but they categorize it as a brown dwarf. But in
the end, it's sort of like a semantic question like
do you call this a small star? Do you call
(28:01):
it a big planet? All right? Sort of like a
like a Pluto question, Right, it's Pluto, a dwarf planet
or a real planet. Um. But there's also a lot
of uncertainty in its mass. It's it's thirty Jupiter masses,
but the uncertainly and that is fifty so it could
be as high as forty five jupiter masses or could
be as low as a fifteen jupiter masses. All right, cool,
and so we're cruising on that's right. And so next
(28:24):
on our tour is a really weird planet. This one's
called Kepler sixteen B. And this one is weird because
it orbits not one star, but it orbits two stars simultaneously.
You mean, like the two stars are are orbiting each
other and there's things orbiting around them. Yeah, it's a
binary star system. So the stars orbit each other like
(28:44):
every forty one days. They're like, you know, running around
each other, and then around one day forty one days.
These are fast moving, huge hot objects, right, They're going
around each other every forty one days. And then this
planet goes around the combination of the two stars every
two hundred and twenty eight days. So the stars are
much closer to each other than the planet is to
(29:06):
the stars. So in the sky of this planet you're
gonna see like basically just two stars together, you know,
two sons together rising and falling. Wow, that's that like
a science fiction movie. That's pretty cool, I know, But
the universe is weirder than of course every science fiction movie.
You've ever seen um, and this one is two hundred
and forty five light years away. It's in the Signets constellation,
(29:27):
and it has about a massive the planet saturn Um
and itself. It's about point seven au away from those stars.
So it's a pretty big it's a pretty big planet,
but it's a reasonable distance from those stars. So does
it have kind of a like a wonky orbit because
it's going around two things that are orbiting each other,
or to the planet, does it just look like one
(29:49):
big sun in the middle there. Yeah. This is one
of the amazing things about gravity, right, is that if
you're the on the outside of a system, the only
thing that matters is the center of man of that system.
And so the stars are orbiting each other, but they're
actually orbiting the center of mass of the two star system,
and the planet is orbiting that that also, and so
(30:09):
it doesn't actually matter to the planet too much. The
planets orbit is the same as if you took those
two stars, added them together, and put them both at
the center of mass of the two stars. It wouldn't
change the planet at all. And I think a lot
of people when they imagine this two star system, they
imagine like you know, one sun raise rises and then
maybe another one in a different periods of these weird
(30:30):
day night cycles like in that that book, the Three
Body Problem. But that's that would require the planet to
go like between the stars, right, But in this case,
the planet just goes around the two stars. So it's
sort of like instead of having one son in the sky,
you have sort of like a you know, two dots
instead of one, but they stay, they stick together. But
wouldn't that be you know, those sons are spinning so
(30:52):
fast around each other, wouldn't that be kind of a
violent process, you know, wouldn't it be just a huge
mass in the middle or is it? Do they think
it's pretty clean that these two sons are just going
around each other. No, you're right, and I don't know
how stable that is, right, Eventually these things are going
to radiate energy and then fall into each other and collide,
and it wouldn't be a very nice place to be
(31:12):
when that happens, you know. That's that's what causes the
gravitational waves that we observe, like two neutron stars orbiting
each other and eventually falling into each other and collapsing,
or two black holes doing that so binary star systems.
Eventually they will lose some of that energy and they
will fall into each other each other, though I don't
know how long that will take. Probably longer than our cruise. Well, um,
(31:32):
good thing they have laundry on the cruise, that's right,
yeah exactly, and we packed a lot of food. Um.
And the next planet is also has named after Kepler,
which is the telescope that discovered it. It's Kepler twenty
two BE. And this one initially seems really exciting because
it's labeled as a possible water world. Um. And when
(31:53):
how do they know it has water? Yeah, they don't.
It turns out that's mostly just hype. Um. When they
discovered it, it it was one of the first plan people
discovered that was sort of inhabitable zone, meaning it was
like about the size of Earth, probably a made of rock,
and the right distance from its star for water to
be liquid on its surface because if it was closer,
(32:15):
it would evaporate, right, yeah exactly, but if it was
further out then it would just be ice, yeah exactly.
And so people are really excited about this and they're like, Wow,
maybe it's a water world, but you know, just because
it has the right. Surface temperature we think it's about
seventy two degrees fahrenheit on the surface doesn't necessarily mean
that there is water there. Now, you know, if there's
a lot of water on on this on this planet,
(32:36):
then it would be in the form of an ocean,
and there are some models that suggest maybe a surface ocean,
but we have no direct evidence that there is actually
any water on Kepler twenty two B. So you know,
labelating a water world is a bit premature, but it
sounds pretty nice. You wrote down here and it's a
temperature there. It's seventy two degrees fahrenheit. Yeah, it's basically
(32:57):
southern California, So you want to feel them movie on
Capito twenty two B. Just come to southern California. Filmly here.
So just because it's in the Goldilocks zone doesn't mean
it has water like is Mars technically in the Goldilocks Zone? No,
I don't think so. Well, that's a good question. Um,
I think it's on the outer edges the things water
on Mars would be frozen, but that's probably mostly because
(33:20):
it doesn't have an atmosphere. So in order to be
to have this surface temperature, you need to have an
atmosphere as well, and so this calculation seventy two degrees
assumes that there's an atmosphere there. Um. So if Mars
had an atmosphere like we think it did a long
long time ago, then water could be liquid on its service.
So I guess the answer is yes, Mars is in
(33:40):
the Goldilocks zone. All right, let's keep cruising through the
universe visiting other planets outside of our Solar system. But
first let's take a quick break. All right, Daniel, I
(34:01):
think our our cruises running a little bit out of time,
running a little bit behind. So I think the captain
is trying to put the pedal to the metal here. Um.
So what are some of the more interesting other planets
that we know about out there in the universe? Yeah, well,
you know, some of the planets out there are super
duper old. Like there's a planet in the constellation Scorpius
that we think is twelve point seven billion years old.
(34:25):
And remember, yeah, I know, how do we know how
old it is? Well, I think we're speculating because the
age of that Solar system, right, and the Milky Way
itself is really old, right. The Milky Way has been
around for thirteen billion years and so that star we
think is about twelve point seven billion years old, and
so we think that the planets around it probably are
(34:46):
the same age. And so this is the planet around
the oldest star we've discovered to have planets. Yeah, it'd
be cool to be the first planet that would be.
That would be pretty cool, bragging rights exactly. So that's
the oldest planet and it's PSR B sixteen twenty twenty
six b. Right, and you think the oldest planet should
be just be called planet number one one? Yeah, a
(35:09):
one exactly. Um. And there's some other weird planets out there.
There's a planet out there which has the title of
the darkest planet, right, And you can see sort of
how much light that these planets reflect by seeing how
much they dim as they pass in front of the
star right to the absorbiting that light. Did they reflect
any of it? And this planet is called t R
(35:31):
E S two B. It's the size of Jupiter, and
it's less reflective than black paint? Like what is going
on in that world? How can be less reflective than paint?
Is it maybe filled with solar panels or something like that? Exactly? Well,
you know, black paint is not entirely black. I mean,
you're an artist, you know, there's like lots of different blacks, right,
(35:52):
and so this is a very black black planet. All right,
that's the darkest planet. What else is on our musty list? Well,
there's the pink ist planet, right. This one's only fifty
seven light years away and the pinkest. Yeah, and based
on the light that we see coming from it, it it
seems like it might be sort of a dark magenta,
maybe a cherry colored planet. And that leads to a
(36:13):
lot of speculations like what's going on on that planet?
How can we tell the color? Um? We can tell
the color based on as we said earlier, like how
the life passes through the planet, and also by doing
subtraction right as it passes in front of the star,
we can try to subtract the light from the star
and just get the light from the planet itself. But
there's a lot of uncertainty there. I mean, we could
(36:34):
think it's pink, and then we get there, we're like,
what this planet is purple? This cruise is a scam
exactly exactly, Um, But maybe I think the most exciting
one in the place we should end our tour is
on the most earthlike planet found so far, the most earthlike,
the one that we are maybe most likely to be
able to visit and live there. Exactly if we actually
(36:58):
do destroy this plan it or make it unhabitable for humanity,
then Kepler for fifty two be is so far our
best option. While it's five hundred light years away, it
seems to be about the size of the Earth, and
it's in the habitable zone so it gets just the
right amount of solar radiation um. It orbits its star
(37:19):
every hundred and thirty days, so it's sort of a
short year. The kicker, the downside of this planet is
that it has about two times the gravity of Earth,
even though it's Earth's size has more mass, so we'd
all have to but we have five hundred years on
the trip over there to all sort of bulk up
and get buff for living on this planet on a cruise.
That's pretty easy. Exactly, well, it'd be a very Darwinian cruise.
(37:44):
You know. If all you did on the cruise was
either the buffet, then your your children would not be
very suitable for living on this planet. But if you
hit the gym on the whole cruise, over there, then
you have a chance of your children surviving. Wait, how
can it be the same size as Earth? But how
twice the gravity? Like more compact or what is it?
Or just more mass more massive? Yeah, it's um, we
(38:05):
think it's Earth sized and so it must have must
be denser somehow. But it's five years away, so we're
not going to get there anytime soon. No, it's gonna
take at least five years to get there, probably more
like a thousand. It's the kind of thing where either
generations would need to live on a colony ship or
you need to develop some sort of cryogenic freezing or
something like that. So um, but you know that technology
(38:27):
is far far in the future. But at least we're
beginning to find these places. We're looking out there in
the universe. We're exploring other solar systems and we're figuring
out where are there possible places for humanity to land. Yeah,
and the cool thing is that we're finding places, right,
We are being successful at hunting planets, that's right, and
turning planets, that's right. And and amazingly, it seems like
(38:50):
about one in five stars has some sort of Earth
like planet, and so it doesn't take too long to
find earthlike planets. Um, there's a lot of them out there.
Of course, that doesn't mean we shouldn't take care of
this one, right, because even the ones that are out
there take a long time to get to. But I
think it gives us some some reason to hope, right,
because we all know not all cruises and will that's right,
(39:12):
We've all there's an equally outbreak and you wish you'd
never gone on a cruise. I hope there's a bathroom
on some of these planets, all right, Well, we hope
you enjoyed that quick flash tour of the universe looking
at other planets out there that we might possibly visit
or live on someday. Thanks for tuning in and thanks
for coming on board. And if you have questions about here,
(39:35):
their planets and anything else in the universe, send them
to us if questions at Daniel and Jorge dot com.
See you next time. If you still have a question
after listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us
(39:56):
at Facebook, Twitter, and Instagram at Daniel and Jorge that's
one word, or email us at Feedback at Daniel and
Jorge dot com. Thanks for listening and remember that Daniel
and Jorge Explain the Universe is a production of I
heart Radio. For more podcast from my heart Radio, visit
the i heart Radio app, Apple Podcasts, or wherever you
(40:17):
listen to your favorite shows.
Hey, I hear that you like taking cruises. I just
recently took my first one last last week. Well, let
me ask you a question. Before you get on the cruise.
Do you do like a lot of research to figure
out where the cruise is going to stop? Or you
just sort of trust them to take you to nice places? Well,
I think the whole point of a cruise is that
you don't have to do any research or worry about anything. Oh,
(00:30):
it's about physical and mental laziness. You just get on
and you gain weight. That's the whole point. Do they
charge you per pound or per pound gain? Exactly? The way?
How much of it stays with you is how much
they charge you. But do you like just hanging out
on the boat or do you like that they take
you to different places to explore? Well, I've only done
it once and it was sort of a nice mix
(00:52):
of both. Like you spend some time at sea just
hanging out on the boat, and you spend some time
like disembarking and exploring some new different country. And what
do you look for when you're embarking and exploring a
new country? Bananas? That's bad. That's about all that I need,
all right? Well, In that case, I have got a
cruise to sell. You do tell how much does it cost? Well,
(01:14):
would you buy a ticket on a cruise that stops
at all sorts of alien planets outside our Solar system?
It depends. I guess you know how how good is
the buffet? It doesn't really like dehydrated food, astern not food,
I don't know. It turns out it's mostly bananas, right,
Dehydrated bananas do are harder to slip on in s
(01:34):
g Alright, the listeners, there is a seat available for
our cruise to exoplanets. Hi. I'm or handmade cartoonists and
(01:57):
the creator of PhD comics. I'm Daniel. I'm a particle
physicist and I might be the only person on the
planet who doesn't like taking cruises. Have you been on
a cruise, Daniel? I have been on exactly one cruise.
Did not like it. Not a fan, No, to me.
I'm not a big fan of hotels, kind of a homebody,
and to me, a cruise is sort of like a
floating hotel you're trapped in. Well, anyways, we hope you
(02:19):
that you are listening to this on a cruise or
maybe not. Uh, and so welcome to our podcast Daniel
and Jorge Explain the Universe, a production of I Heart
Radio in which we cruise around the universe finding weird
and interesting stuff to dig up and explain to you
to download into your brain. Um, the buffet of fascinating physics,
(02:39):
that's right. So you just have to hop on board,
sit back, and relax, and and cruise around with us
through the furthest reaches of human knowledge. That's right. Today's
efforts to fatten up your cerebral cortex. We are going
to be zooming around the universe and wondering what does
it look like out there? So today on the podcast,
(03:01):
we'll be talking about water planets outside of our Solar system,
Like where are they? What do we know about other
planets that are not the ones that are right immediately
next to us? And this is sort of the first
question I thought about when I heard about the discovery
(03:22):
of planets around other solar systems, Because what's the point
of finding these planets if you can't imagine going there,
if you can't like ever go see them and swimming
those alien oceans? And so I wondered, like, what are
these planets like? Are they like Earth? Or they like
sad or they like Jupiter. Are they like something totally
weird and different? Right, because we know what the planets
(03:43):
are like in our Solar system, right, There's some there
are just big balls of gas. There are some there
are just big rocks. And so the question is is
that kind of the model for the rest of the
universe or our planets maybe totally different outside of our
Solar system. And that's such an citing moment in science
when we first get to sort of crack open that
box and learn whether the things we've known for hundreds
(04:06):
of years are typical, like representative, like the rest of
the universe is like this, or whether we've been misled
into thinking that most solar systems are like ours, when
in fact ours is an anomaly. We never know until
we go and explore those other solar systems, until we
actually get the data. So those moments in science, when
we get to ask nature of these questions and learn
(04:27):
for the first time in human history what the sort
of larger cosmic context is. That's the kind of stuff
that gets me really excited, because you know, if you
watch science fiction movies or Star Trek or Star Wars,
you would think that every other planet in the universe
looks a lot like the Earth, maybe because most of
them are actually filmed on Earth. Wait, what a surprising
number of planets look like southern California, so nondescript desert
(04:51):
outside of the Angus. That's right, exactly. But you know,
you've got to give people credit, Like, all we can
do is imagine sort of what we know and extrap
a little little bit from there. It's really hard to
imagine something totally new, something totally alien, something outside of
our experience. That takes unfathomable creativity, really, and so what
we need is more data. We need to go out
(05:12):
there and see what are these planets like? And uh
and so I'm as an avid fan of science fiction,
I'm desperate for this data. I'm really curious to know
what do other planets and around other stars actually look like. Yeah,
because because all those movies and TV shows could be right, right,
you know, there could be a lot of planets out
there that look just like the Earth, you know, blue
and green and with deserts and um humanoid blue people.
(05:38):
That's right, It certainly could be. It could be that
planets or of a few varieties you know, rocky with
some water around them, um, gas, giants, etcetera. Or could
be that there's a whole other class of planet that
we've never even imagined before, right, that we've never seen
just because there isn't one example in these eight planets
around our Solar system. But you know, there's billions of
(05:58):
planets in the universe. So the odds that we have
an example of every kind of planet in these eight
seem pretty probable right there. It's got to be some
crazy surprises out there. Yeah, we only have eight data points,
you know, eight examples. Yeah, imagine you have what a
planet can be like. Yeah, imagine you have a bag
of fifty billion marbles and you get to draw eight
(06:19):
marbles out and from that extrapolate what the other fifty
billion look like, right, I mean, that's a pretty small
lever armed to make some guesses or maybe not just
what they're like, but how often earthlike planets happen out there?
You know, it's super rare to be a blue and
green and beautiful with them jungles and desserts, or is
(06:40):
it pretty common? That's right? And you can take this
question from from the sort of like fantastical creative side,
like what do they look like. And you can take
it from the practical side, like you were saying, like,
could we live on any of those or is it
worth sending colony ships to any of these other planets
to sort of expand the human diaspora. That's a great question.
And the mind blowing thing is that up until maybe
(07:00):
what like twenty years ago, twenty five years ago, we
didn't really have confirmation or no for sure that there
were other planets. Like thirty years ago, for all we know,
we could have been the only planets in the universe.
That's right. We had no evidence, We had no evidence
for other planets, and and it's because it's really hard
to see planets around other stars, and so we thought
(07:20):
it pretty unlikely that there were no planets around any
other stars. But we didn't actually know until thirty years ago.
And since then the field is taken off and we've
we've learned about a lot about these planets, and now
we're even at the point we're starting to get some
glimpses as to what they might look like. It's a
fascinating moment in astronomy. Yeah, all right, well let's get
(07:41):
into it. And and so there's a technical term Daniel, Right,
for planets that are outside of our solar system. Right,
there's a science term for them, that's right. Were you
on the committee that made this name, by the way,
I was not. I would have um, I should have been. Well,
they're they're officially called exo planets, which always makes me
think of like you know, exo skelet teens or you know,
(08:02):
like like an armor or like you know bugs. Well,
that's exactly right, Like exo exo skeleton is a skeleton
on the outside. So to me, XO means like outside
like a way, So exo planets are like planets outside
our solar system. To me, it makes a lot of sense. Also,
it launched a whole set of names of new fields,
you know, like exo planetology, exo meteorology, extro exo biology. Right,
(08:29):
these are some extra exo paleontology. You can just add
exo to your scientific field and all of a sudden
it's much cooler. EXO psychology. Yeah, exo cartoonists, exo economist,
XO podcasts. Technically our podcast is XO solar system. And
(08:51):
what in a couple of years, the signal will probably
leave the solar system. Yeah, yeah, exactly Um, are these
podcast waves and they are broadcast over the radio will
leave the solar system. You're right, Oh my gosh, I'm
I'm having a moment here realizing that our words are
transmitting through the cosmos. You're freaking out all of a sudden,
I have stage fright because the stage has just grown dramatically.
(09:14):
All right, well, let's the question is then, what are
these What do we know about these planets that are
outside of our solar system? So we have a pretty
good idea of the ones in our solar system. Right,
there's eight. There used to be nine. Now they're eight
because some people did not like Pluto, and we know
that there are some of them are gassing somewhere. There
are big somewhere. The are hot and small and rocky,
(09:36):
but we we really don't um had any idea what
they would look like outside of our solar system. Right,
you want to hear my favorite Pluto planet um controversy story. Yeah,
for sure. Um. Well, there's a fantastic planetarium in Chicago. Favorite,
so you have several favorite. Um, there's this fantastic planetarium
(09:56):
outside Chicago in Chicago, downtown Chicago, the Adler Planetarium, And
it was built before Pluto was discovered. So it's an old,
old building and so they have eight planets on there.
And you know, then Pluto was discovered, and for decades
it was sort of out of date. They're like, should
we add Pluto? Should we get around to it? You know,
Chicago bureaucracy moved slowly, and then Pluto was demoted and
(10:19):
so they didn't need to add it anymore, and all
of a sudden it was back up to date without
doing anything. So I guess the lesson is, you know,
just wait and maybe you know what you have is
going to be correct again. Science sort of oscillates. Lesson
is if you procrastinate, you might save you a lot
of work there exactly. But I was wondering what do
people think about what do they imagine when you talk
(10:42):
about planets around other stars? And so I went around
campus UC Irvine and asked people if they thought that
planets around other stars sort of looked like our planets
or look totally different or something else. Yeah, so close
your eyes. Maybe not if you're driving, but if you're
not driving, um and you're in a cruisers something, close
your eyes and try to imagine and another planet outside
(11:03):
of a different star out there in the universe and
try to imagine what that planet might be like. Here's
what people had to say. When you think about planets
in other solar systems, how do you imagine they look like?
Do they look like the Earth or like Jupiter or
something totally new and weird? Maybe maybe not. I mean
every planet has a like different I guess, so probably
(11:25):
like that too for the most part. I imagine sort
of gas giants, dead rocks like for like, most planets
are not life sustaining, as I tend to imagine them.
They are very rough, uh and very different, but there's
no life. The condition would be totally different. I guess
they'd all be different, but it's going to be different
(11:47):
between depending on what another in the Goldilog zone or not,
how much light gravity that acts upon the planet. So
I'm honestly not really certain what's going to end up
around extra planets because it just depends significantly on the
different factors. The ones that we've most discovered, like massive
(12:09):
like Jupiter, gas use and also close to the Sun. Uh,
most of them are not like Earth. I know, We've
also found some that are comparable, So I imagine most
of them would be gaseous and pretty uninhabitable. I know
that people have speculation that there are you know, habitable
planets out there, um, but there are a lot of
(12:31):
them that they are different, you know, something that might
I don't know, rain diamonds or I don't know my
thing raining in there. I don't know, raining diamond sounds
pretty dangerous. I feel like they might be similar, but
maybe it depends on the placement of the planets, like
in the Solar System or like in our galaxy in
(12:52):
gerl I don't know. Alright, some pretty eclectic answers there,
you know, I think a lot of people were. I
saw people on their faces sort of scratching their heads
and wondering, uh, you know, and wondering what they would
be like, and trying to be creative. But you know,
in the end, we don't have like a really great
well of inspiration outside of our own Solar System, So
(13:12):
I think, you know, before we get really creative answers,
like I was saying, before, we're gonna need some data
to sort of spark the creativity. I like the person
we said, is it's either gas or solid? What about
an all liquid planet? Right? A planet that's just like
a blow, like a drop in space. That would be
pretty cool. Is that possible? Can you have a totally
(13:33):
liquid planet? I don't think so. I think at the
core it would be so dense that it would have
to solidify. But you know, proved me wrong. Universe. Let's
discover an all liquid planet that would be awesome with
fish swimming like all the way through it. That would
be really cool. Isn't there a moon in Jupiter? We
talked about this, right Europa. Isn't it mostly like a
giant ocean? Well, there's kind of like a big proplet.
(13:56):
There is a really huge ocean with more water ear
than he's on Earth. But we also think that there's
a solid core, so it's it's not just a liquid
drop in space. That would be pretty awesome. Somebody out
there find me the science fiction story. Somebody must have
written about an all liquid planet. You could call it
water World. Oh wait, that's been done. That's got to
(14:20):
be successful. That that name just screams commercial success. I
can see it already, all right, so um so, but
some people seem skeptical that there would be life in it. Yeah, exactly, Um,
but you know, we don't know. Um. I like the
person that said that maybe other planets on other planets
that have really weird weather, like raining diamonds. That sounds
pretty cool to me. Is that possible? That's possible, right,
(14:42):
I suppose it's possible. I mean, I don't know how
you form diamonds in the atmosphere, but you know, hey,
there's a lot of worlds out there, so there's room
for everything. That sounds like a rap video. You need
a diamond umbrella program. It does sound like a rap video.
That's awesome, So give us the rap lyrics that involves
raining guaments. Go ahead, can your freestyle? I probably could,
(15:08):
but right now I just have Old Town Road in
my head because my kids keep listening to it over
and over. So today you thought it'd be cool, You're
gonna take us on a tour, on a cruise of
all all of the different planets that we know about
that are outside of our solar system, right, I mean,
not all of them, but some of the most interesting ones. Yeah,
because by now we have done a lot of work,
(15:30):
and we have amazing satellites and teams of astronomers figuring
out where those worlds are, counting them, trying to measure
quantities and qualities about them, and we're getting more and
more sort of images about these planets, not direct images yet,
but information about what these planets might look like. And
there are some weird ones already, you know, we're just
scraping the surface, and so I thought it'd be really
(15:50):
cool to sort of get a tour of the weirdest,
most interesting planets that we found so far, and just
to give people a context. Um, we know that there
are probably billions of planets out there, but the ones
that we've sort of detected and and there are definitely there,
that's more than like the thousands, right, that's right. Yeah,
we we speculate that every star has several planets because
(16:13):
so far, um, you know, every star we've looked at,
we've seen planets. But you're right. In terms of direct discoveries,
we found just over four thousand planets in just over
three thousand solar systems, and that number just keeps going
up because we have these amazing telescopes that are very
efficient down now. So that number is as of July one,
(16:33):
two thousand nineteen, we have found more than four thousand
planets and other solar systems, a huge number. And that's
just the beginning, right, because we know there are billions
of them in our galaxies and other galaxies, right, absolutely,
And the next a few decades that number will explode
and we'll be up in the thousands and thousands and millions.
But you're right, there are billions of planets just in
(16:54):
our galaxy. And maybe what's really cool is that we
don't just know these days that the planets are there.
We can't sort of we don't have photographs of them,
of them, but we know we seem to be finding
on more and more about these planets through really like
cool and clever physics and clever observations, right, that's right.
The first things we figure out about a planet are
sort of how fast it's orbiting around the star, because
(17:17):
either we see it's like gravitational effect on the star.
We see tugging the star back and forth. And based
on that we can tell how often it goes around
or maybe sometimes they pass in front of the star
so they block the life from the star. Those the
two main methods, and those methods tell us something about
the orbit, right, how fast is it going around? And
also how much mass is there in the planet, right,
(17:40):
And so that's already a lot of information like how
far is it from the Sun that we can know that,
how much solar radiation is there because we know how
bright the star is, what is the orbit of it.
So already we have a lot of information just from
the indirect measurements, just from discovering that it's there, tells
you how big it is, you know, right, like if
you were on that planet, how short the days would be, right, yeah,
(18:02):
exactly years, exactly and um. And now we're starting to
do even more clever stuff, like we can we can
see how the light from the star passes through the
atmosphere of that planet, right, So sort of like looking
at a sunset on another planet. Right, you know how
when the sun sets over the Earth, the light passes
(18:22):
through a lot of atmosphere and it looks red because
it's passed through so much air. We talked about on
another podcast. You know why the sunset looks red because
of the qualities of the atmosphere tend to bounce away
the blue light and that's also why the sky is blue.
But we can do that on other planets. We can
see suns on other solar systems setting over planets on
(18:43):
their in their solar system. And we can see how
the light changes, and that tells us something about the
atmosphere on those planets, like if the the color changes
or something like that. Right, yeah, I can tell you
what kind of gases in there? Is their water vapor
in there? Right? Is there me thing in there? What's
the atmosphere composition of those planets? Is there an atmosphere
(19:04):
at all? First of all? And if so, what's in it?
And I've heard that you can even sort of tell
the weather a little bit, like from the delay between
the when the light gets blocked or the temperature gets
um changes, you can sort of tell if there's something
swirling in that atmosphere. Not just if there's an atmosphere,
but just like how how much it swirls around inside
(19:25):
of that planet. I know, it's crazy, right, We're measuring
the velocity of gases around other planets, around other stars
that are light years away. I mean, it's like science fiction.
If you suggested this thirty years ago, people would say
that's impossible, right, But now we're doing it, people are
writing papers about it. We're like actually learning facts about
these things. So extrapolate like thirty years from now, you know,
(19:47):
we're gonna have like Google Earth around all these planets basically,
and so far that's all without even taking a picture
of them, right, Like, it's just all from like counting
photons that come and hit the smallest little sensors in
our telescopes. Yeah, because actually and that's sort of a picture. Um.
The other cool way that they learn about what's sort
of on the planet is that they take the picture
(20:08):
of the star when the planet is in front of
the star, and then they subtract the star and they
see what's left and they try to find those photons
that came just from the planet, not from the star itself.
And that's really hard to do because you're talking about
a really little object in front of a really bright
object really far away. But it gives you a sense
(20:28):
of what light is coming from that planet, and that
gives you a sense of like what color is that planet,
what gases are on that planet, because remember every gas
amidst light of different frequencies, and so it tells you
sort of what the composition of that is. So we
have two ways to figure out not just like where
this where this planet is and how fast it's moving
around that star, but what's on that planet? What does
(20:50):
it look like. All right, so that's sort of how
we can see other planets and how many there are
out there, and so let's let's um, let's set sail, Daniel,
Let's go explore the universe visit other planets. But first
let's take a quick break. All right, I know, I
(21:16):
have my cruise pass, I've got my I've losen my
pants a little bit to make room for the buffet.
We are now ready to set sail on this extra
solar cruise to other planets. All right, Well, I thought
it'd be fun to start with the closest planet, right
because we're gonna leave the Earth and they are first
stop leaving Solar System to Yeah, we'll leave a Solar system.
(21:39):
Our first stop is Proximus Centauri. It's a star, and
this planet that's orbiting Proximus Centauri, it's called Proximus Centauri B.
And let's be because it's the second planet they found there,
Like they really need you on this naming committee because
they're finding so many planets, they're just like running out
of name so they just like have a recipe for mening.
I think is a he's a good name. Why not?
(22:02):
He is a good name? I don't know. We'll have
to ask the citizens when we get there. But it's
four point two light years from Earth, which is pretty close.
I feel it's pretty close in the scale of the galaxy, right,
the galaxy is like a hundred thousand light years across,
So that's the closest planet to us. I mean it's
like like in four point two years, this podcast will
(22:23):
have arrived at that planet. Yeah, and so in eight
point four years we should expect a bunch of good
questions or people complaining about how we name their their planet. Right,
But no, I mean it's sort of reachable maybe, right.
I mean, I know we can't go at the speed
of light, but you know we can if we go
as fast as we can, we might get there within
a lifetime. No, exactly, it's totally reachable. And you know,
(22:43):
we could even send something there that could arrive and
send us information within a lifetime. Right. You know, we
build a solar sale, we attach a little thing to it.
The thing could reasonably get up to maybe a half
the speed of light, taking maybe ten years to get there,
five years to send data back. So you're talking about
a fifteen year project lifetime to maybe get like pictures
(23:04):
of Proximus Centauri. So yeah, it's not that far away
compared to the other planets we're gonna talk about, but
it's also not that nice a place to be. If
you ask me, all right, what do we know about
this planet B. Well, we know that it's very close
to its star, right, and so we we call this
thing the A U. The astronomical unit is the Earth
(23:24):
from is the distance from the Earth to the Sun,
so it's useful metric. And this Proximus Centauri B is
only zero point zero five a U, so it's twenty
times closer to its star than the Earth is to
the Sun. So if you're standing on it, the Sun
would look twenty or more times bigger in the sky.
And also it goes around that star and only eleven
(23:47):
point two earth days, so it's like it's zipping around.
It's a hot little planet zipping around the star in
a hurry. So you know, if you're in for a
beach vacation you want a lot of rays, then yeah,
I guess it's a good place to stop first on
our cruise. That that's why it's called planet B and
burn and burning off. But all the bananas are burnt
(24:08):
also because that's probably too much sun even for bananas. So,
but that's the planet B. What about planet A and C?
And does it have any other planets in its neighborhood?
They think that there might be another planet, and they
call this planet wait for it, see right? What? Yeah?
Exactly why they didn't call the first one A that's
(24:30):
beyond my technical knowledge, all right, Um, So that's that's
the first stop in our cruise. That's the closest one, right,
that's right Fort Lauderdale, that's right exactly. Um. Now, the
next planet on our tour is the smallest planet that
has ever been found outside our solar system. And I
(24:51):
have no idea how to pronounce this planet is d
r a U g r. It sounds like maybe a
klingon world. What do you think? How do you think
that's pronounced? I think that's it's like a lord of
the rings underworld beast or something drog drog um. Well,
this planet is so small as only twice as big
as our moon, and we detected it. We can tell
(25:11):
where it is. Yeah, exactly, It's amazing that's such a
small planet can even be detected, right, Um, And this
one is two thousand, three hundred light years away. It's
in the Virgo constellation. And the other really crazy thing
about it is that it's not orbiting like a normal star.
It's orbiting a pulsar, and a pulsar is a pulsar
is one of these stars that emits that that periodically
(25:34):
emits a huge amount of radiation. Right, it pulses. That's
an amazing feed of detection, right that we can tell
so far away such a small thing. Yeah, it really
is amazing. And it also wouldn't be a great place
to live because you don't want to be living near
your pulsar. I mean, this is basically a neutron star
with a huge magnetic field lasting radiation. Uh so not
(25:55):
a cozy place. So far. I'm doing a pretty terrible
job of advertising food something this cruise. So far, this
cruise doesn't make me want to get off the boat. Yeah,
zero star is so far in the help for this cruise. Alright.
So the next star we're gonna look at has a
terrible name. It's but it's the biggest, the biggest planet
that has ever been discovered. It's called Hr sixty two
(26:18):
B and it is thirty times the size of Jupiter.
How do you pronounce that one? Hot in the original
cling on the mass of thirty jupiters or the size
of thirty jupiters. It's the size of No, sorry, you're right,
it's the mass of thirty jupiters. Yeah, exactly. And so
take Jupiter, which is already like, you know, what, hundred
(26:38):
times the massive Earth and multiply by thirty, Like this
is a ginormous planet. But but it's not super far away.
It's kind of closed, right, a hundred light years. Yeah,
it's a hundred ten light years from Earth, and so
it's you know, also potentially reachable. But it's sort of interesting,
like how big can a planet get? This one is
really on the verge of the maximum size for a planet,
(27:00):
because any bigger and the gravitational force will be so
strong that it will essentially turn into a star. So
this jew this is like as big as a planet
can get before it ignites and becomes a star. What
else do we know about it? Is it like a
gas like Jupiter? Or we just know sort of the
mass of it and where it is. That's all we
know about that one so far. You know, a lot
(27:20):
of these planets we you know, some of these techniques
work better on some planets than others, and so we
don't always get to get to see like the atmosphere
of these planets. Um. And that's also all these atmospheric
techniques that we talked about that are so amazing, these
are pretty new and they require some fancy technology. So
we don't have that information about all of the stars
so far. But that maybe gives us a kind of
(27:40):
a range right of planets out there in the universe,
Like they can go as small as twice as high
as on the Moon, and they can go as big
as dirty times Jupiter. Yeah, exactly. Um. And at first
people thought, oh, maybe this is a star, you know,
but they categorize it as a brown dwarf. But in
the end, it's sort of like a semantic question like
do you call this a small star? Do you call
(28:01):
it a big planet? All right? Sort of like a
like a Pluto question, Right, it's Pluto, a dwarf planet
or a real planet. Um. But there's also a lot
of uncertainty in its mass. It's it's thirty Jupiter masses,
but the uncertainly and that is fifty so it could
be as high as forty five jupiter masses or could
be as low as a fifteen jupiter masses. All right, cool,
and so we're cruising on that's right. And so next
(28:24):
on our tour is a really weird planet. This one's
called Kepler sixteen B. And this one is weird because
it orbits not one star, but it orbits two stars simultaneously.
You mean, like the two stars are are orbiting each
other and there's things orbiting around them. Yeah, it's a
binary star system. So the stars orbit each other like
(28:44):
every forty one days. They're like, you know, running around
each other, and then around one day forty one days.
These are fast moving, huge hot objects, right, They're going
around each other every forty one days. And then this
planet goes around the combination of the two stars every
two hundred and twenty eight days. So the stars are
much closer to each other than the planet is to
(29:06):
the stars. So in the sky of this planet you're
gonna see like basically just two stars together, you know,
two sons together rising and falling. Wow, that's that like
a science fiction movie. That's pretty cool, I know, But
the universe is weirder than of course every science fiction movie.
You've ever seen um, and this one is two hundred
and forty five light years away. It's in the Signets constellation,
(29:27):
and it has about a massive the planet saturn Um
and itself. It's about point seven au away from those stars.
So it's a pretty big it's a pretty big planet,
but it's a reasonable distance from those stars. So does
it have kind of a like a wonky orbit because
it's going around two things that are orbiting each other,
or to the planet, does it just look like one
(29:49):
big sun in the middle there. Yeah. This is one
of the amazing things about gravity, right, is that if
you're the on the outside of a system, the only
thing that matters is the center of man of that system.
And so the stars are orbiting each other, but they're
actually orbiting the center of mass of the two star system,
and the planet is orbiting that that also, and so
(30:09):
it doesn't actually matter to the planet too much. The
planets orbit is the same as if you took those
two stars, added them together, and put them both at
the center of mass of the two stars. It wouldn't
change the planet at all. And I think a lot
of people when they imagine this two star system, they
imagine like you know, one sun raise rises and then
maybe another one in a different periods of these weird
(30:30):
day night cycles like in that that book, the Three
Body Problem. But that's that would require the planet to
go like between the stars, right, But in this case,
the planet just goes around the two stars. So it's
sort of like instead of having one son in the sky,
you have sort of like a you know, two dots
instead of one, but they stay, they stick together. But
wouldn't that be you know, those sons are spinning so
(30:52):
fast around each other, wouldn't that be kind of a
violent process, you know, wouldn't it be just a huge
mass in the middle or is it? Do they think
it's pretty clean that these two sons are just going
around each other. No, you're right, and I don't know
how stable that is, right, Eventually these things are going
to radiate energy and then fall into each other and collide,
and it wouldn't be a very nice place to be
(31:12):
when that happens, you know. That's that's what causes the
gravitational waves that we observe, like two neutron stars orbiting
each other and eventually falling into each other and collapsing,
or two black holes doing that so binary star systems.
Eventually they will lose some of that energy and they
will fall into each other each other, though I don't
know how long that will take. Probably longer than our cruise. Well, um,
(31:32):
good thing they have laundry on the cruise, that's right,
yeah exactly, and we packed a lot of food. Um.
And the next planet is also has named after Kepler,
which is the telescope that discovered it. It's Kepler twenty
two BE. And this one initially seems really exciting because
it's labeled as a possible water world. Um. And when
(31:53):
how do they know it has water? Yeah, they don't.
It turns out that's mostly just hype. Um. When they
discovered it, it it was one of the first plan people
discovered that was sort of inhabitable zone, meaning it was
like about the size of Earth, probably a made of rock,
and the right distance from its star for water to
be liquid on its surface because if it was closer,
(32:15):
it would evaporate, right, yeah exactly, but if it was
further out then it would just be ice, yeah exactly.
And so people are really excited about this and they're like, Wow,
maybe it's a water world, but you know, just because
it has the right. Surface temperature we think it's about
seventy two degrees fahrenheit on the surface doesn't necessarily mean
that there is water there. Now, you know, if there's
a lot of water on on this on this planet,
(32:36):
then it would be in the form of an ocean,
and there are some models that suggest maybe a surface ocean,
but we have no direct evidence that there is actually
any water on Kepler twenty two B. So you know,
labelating a water world is a bit premature, but it
sounds pretty nice. You wrote down here and it's a
temperature there. It's seventy two degrees fahrenheit. Yeah, it's basically
(32:57):
southern California, So you want to feel them movie on
Capito twenty two B. Just come to southern California. Filmly here.
So just because it's in the Goldilocks zone doesn't mean
it has water like is Mars technically in the Goldilocks Zone? No,
I don't think so. Well, that's a good question. Um,
I think it's on the outer edges the things water
on Mars would be frozen, but that's probably mostly because
(33:20):
it doesn't have an atmosphere. So in order to be
to have this surface temperature, you need to have an
atmosphere as well, and so this calculation seventy two degrees
assumes that there's an atmosphere there. Um. So if Mars
had an atmosphere like we think it did a long
long time ago, then water could be liquid on its service.
So I guess the answer is yes, Mars is in
(33:40):
the Goldilocks zone. All right, let's keep cruising through the
universe visiting other planets outside of our Solar system. But
first let's take a quick break. All right, Daniel, I
(34:01):
think our our cruises running a little bit out of time,
running a little bit behind. So I think the captain
is trying to put the pedal to the metal here. Um.
So what are some of the more interesting other planets
that we know about out there in the universe? Yeah, well,
you know, some of the planets out there are super
duper old. Like there's a planet in the constellation Scorpius
that we think is twelve point seven billion years old.
(34:25):
And remember, yeah, I know, how do we know how
old it is? Well, I think we're speculating because the
age of that Solar system, right, and the Milky Way
itself is really old, right. The Milky Way has been
around for thirteen billion years and so that star we
think is about twelve point seven billion years old, and
so we think that the planets around it probably are
(34:46):
the same age. And so this is the planet around
the oldest star we've discovered to have planets. Yeah, it'd
be cool to be the first planet that would be.
That would be pretty cool, bragging rights exactly. So that's
the oldest planet and it's PSR B sixteen twenty twenty
six b. Right, and you think the oldest planet should
be just be called planet number one one? Yeah, a
(35:09):
one exactly. Um. And there's some other weird planets out there.
There's a planet out there which has the title of
the darkest planet, right, And you can see sort of
how much light that these planets reflect by seeing how
much they dim as they pass in front of the
star right to the absorbiting that light. Did they reflect
any of it? And this planet is called t R
(35:31):
E S two B. It's the size of Jupiter, and
it's less reflective than black paint? Like what is going
on in that world? How can be less reflective than paint?
Is it maybe filled with solar panels or something like that? Exactly? Well,
you know, black paint is not entirely black. I mean,
you're an artist, you know, there's like lots of different blacks, right,
(35:52):
and so this is a very black black planet. All right,
that's the darkest planet. What else is on our musty list? Well,
there's the pink ist planet, right. This one's only fifty
seven light years away and the pinkest. Yeah, and based
on the light that we see coming from it, it it
seems like it might be sort of a dark magenta,
maybe a cherry colored planet. And that leads to a
(36:13):
lot of speculations like what's going on on that planet?
How can we tell the color? Um? We can tell
the color based on as we said earlier, like how
the life passes through the planet, and also by doing
subtraction right as it passes in front of the star,
we can try to subtract the light from the star
and just get the light from the planet itself. But
there's a lot of uncertainty there. I mean, we could
(36:34):
think it's pink, and then we get there, we're like,
what this planet is purple? This cruise is a scam
exactly exactly, Um, But maybe I think the most exciting
one in the place we should end our tour is
on the most earthlike planet found so far, the most earthlike,
the one that we are maybe most likely to be
able to visit and live there. Exactly if we actually
(36:58):
do destroy this plan it or make it unhabitable for humanity,
then Kepler for fifty two be is so far our
best option. While it's five hundred light years away, it
seems to be about the size of the Earth, and
it's in the habitable zone so it gets just the
right amount of solar radiation um. It orbits its star
(37:19):
every hundred and thirty days, so it's sort of a
short year. The kicker, the downside of this planet is
that it has about two times the gravity of Earth,
even though it's Earth's size has more mass, so we'd
all have to but we have five hundred years on
the trip over there to all sort of bulk up
and get buff for living on this planet on a cruise.
That's pretty easy. Exactly, well, it'd be a very Darwinian cruise.
(37:44):
You know. If all you did on the cruise was
either the buffet, then your your children would not be
very suitable for living on this planet. But if you
hit the gym on the whole cruise, over there, then
you have a chance of your children surviving. Wait, how
can it be the same size as Earth? But how
twice the gravity? Like more compact or what is it?
Or just more mass more massive? Yeah, it's um, we
(38:05):
think it's Earth sized and so it must have must
be denser somehow. But it's five years away, so we're
not going to get there anytime soon. No, it's gonna
take at least five years to get there, probably more
like a thousand. It's the kind of thing where either
generations would need to live on a colony ship or
you need to develop some sort of cryogenic freezing or
something like that. So um, but you know that technology
(38:27):
is far far in the future. But at least we're
beginning to find these places. We're looking out there in
the universe. We're exploring other solar systems and we're figuring
out where are there possible places for humanity to land. Yeah,
and the cool thing is that we're finding places, right,
We are being successful at hunting planets, that's right, and
turning planets, that's right. And and amazingly, it seems like
(38:50):
about one in five stars has some sort of Earth
like planet, and so it doesn't take too long to
find earthlike planets. Um, there's a lot of them out there.
Of course, that doesn't mean we shouldn't take care of
this one, right, because even the ones that are out
there take a long time to get to. But I
think it gives us some some reason to hope, right,
because we all know not all cruises and will that's right,
(39:12):
We've all there's an equally outbreak and you wish you'd
never gone on a cruise. I hope there's a bathroom
on some of these planets, all right, Well, we hope
you enjoyed that quick flash tour of the universe looking
at other planets out there that we might possibly visit
or live on someday. Thanks for tuning in and thanks
for coming on board. And if you have questions about here,
(39:35):
their planets and anything else in the universe, send them
to us if questions at Daniel and Jorge dot com.
See you next time. If you still have a question
after listening to all these explanations, please drop us a line.
We'd love to hear from you. You can find us
(39:56):
at Facebook, Twitter, and Instagram at Daniel and Jorge that's
one word, or email us at Feedback at Daniel and
Jorge dot com. Thanks for listening and remember that Daniel
and Jorge Explain the Universe is a production of I
heart Radio. For more podcast from my heart Radio, visit
the i heart Radio app, Apple Podcasts, or wherever you
(40:17):
listen to your favorite shows.
Hosts And Creators
Daniel Whiteson
Kelly Weinersmith
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