Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomie podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky.
Speaker 2: Welcome back today. You've brought us some really compelling material
Speaker 2: about one of the most perplexing discoveries to come out
Speaker 2: of the James Web Space Telescope recently.
Speaker 3: That's right. It comes from a Carnegie led team and
Speaker 3: it's all focused on one specific exoplanet that is well,
Speaker 3: it's really challenging some core assumptions, and.
Speaker 2: Our mission for this deep dive is to get to
Speaker 2: the heart of that. We want to unpack the data
Speaker 2: and figure out why a planet that by all rights
Speaker 2: should be a dead, scorched piece of rock seems to
Speaker 2: have a thick, thriving atmosphere. So the planet we're talking about,
Speaker 2: it's called TOI five sixty one B. And just to
Speaker 2: set the stage, this is a super earth. It's rocky,
Speaker 2: it's ultra hot, and it's so close to its star
Speaker 2: that honestly, the model is all predicted it would have
Speaker 2: been blasted clean of any atmosphere billions of years.
Speaker 3: Ago, and yet it hasn't. The data is it's pretty unambiguous.
Speaker 2: So this isn't just some small update. We're talking about
Speaker 2: something that could fundamentally rewrite our understanding of how planets
Speaker 2: survive in extreme environments exactly.
Speaker 3: And it's not just about survival this one observation. It
Speaker 3: just up ends the conventional wisdom about these so called
Speaker 3: ultra short period planet.
Speaker 2: Ultra short period meaning they orbit their star in what
Speaker 2: in less.
Speaker 3: Than one Earth day. It's an entirely different class of world. Yeah,
Speaker 3: and the context here is just as important. That this
Speaker 3: isn't just any star system. It's ancient. We're looking at
Speaker 3: a planet that is fundamentally different from anything in our
Speaker 3: Solar system, and it's giving us this incredible window into
Speaker 3: how planets might have formed in a a very different
Speaker 3: chemical environment way back in the early days of the universe.
Speaker 2: Okay, let's untack this. I think we have to start
Speaker 2: with the planet itself, the sheer extremity of its environment.
Speaker 3: Absolutely, the conditions are almost unimaginable.
Speaker 2: So let's lay out the basic profile. We know it's
Speaker 2: a rocky planet, a super Earth. What does that actually
Speaker 2: mean in terms of its size and mass?
Speaker 3: So super Earth is a category for planets that are
Speaker 3: more massive than Earth, but significantly less massive than our
Speaker 3: ice giants like Neptune. In this case, TOI Fi sixty
Speaker 3: one B is firmly terrestrial. It has a solid surface,
Speaker 3: but it's packing about twice the mass of our own planet.
Speaker 2: Twice the massive Earth. That's substantial, But you're right, the
Speaker 2: mass is only part of the story. The location is
Speaker 2: it's the real shock ra here really is. The sources
Speaker 2: say it orbits its star one fortieth the distance of
Speaker 2: Mercury from our Sun one fortieth.
Speaker 3: I'm trying to even picture that.
Speaker 2: It's hard to visualize. So take Mercury, which is already
Speaker 2: right up against the Sun, practically skimming its surface from
Speaker 2: our perspective right now, imagine moving it f forward thy
Speaker 2: times closer to that furnace that's the neighborhood TOI five
Speaker 2: sixty one B lives in.
Speaker 3: So a year on this planet, one full orbit is
Speaker 3: just ten point five six hours.
Speaker 2: Just over ten hours. It completes an entire trip around
Speaker 2: its star in less time than a work down Earth.
Speaker 3: That speed is just dizzying, and the radiation, I mean,
Speaker 3: the amount of energy hitting that surface must be terrifying.
Speaker 3: Terrifying is a good word for it. Scorching almost feels
Speaker 3: like an understatement if you were to calculate the flux
Speaker 3: of stellar energy bathing this planet, it's just astronomical.
Speaker 2: And what does that kind of intensity do to a
Speaker 2: planet's atmosphere.
Speaker 3: Well, it has a couple of immediate and usually devastating implications. First,
Speaker 3: the gas envelope is exposed to these incredibly powerful solar winds,
Speaker 3: and these winds are constantly, relentlessly stripping away the lighter
Speaker 3: elements hydrogen, helium. They're just getting blasted off the top
Speaker 3: of the atmosphere into space.
Speaker 2: So it's like a constant erosion.
Speaker 3: Process, a very aggressive one. And that's just the first problem.
Speaker 3: The second is the heat itself. The energy input is
Speaker 3: so high that the gas molecules get heated up, they
Speaker 3: move faster and faster, and they can actually achieve escape velocity.
Speaker 3: They literally boil off the planet over time.
Speaker 2: So, based on everything we thought we knew, if this
Speaker 2: planet ever had an atmosphere should be long gone.
Speaker 3: It should be a distant memory. For a small, hot,
Speaker 3: rocky planet like this, any primordial atmosphere it formed with
Speaker 3: should have been lost within say, the first few hundred
Speaker 3: million years of.
Speaker 2: Its life, and this star system is much much older
Speaker 2: than that.
Speaker 3: Much older. We're talking about a system that's around ten
Speaker 3: billion years old. After that amount of time, any atmospheric
Speaker 3: remnant should be well negligible, a wisp of vapor at most.
Speaker 3: But that is not what the JWST is telling us.
Speaker 2: And there's another complication. The proximity to the star means
Speaker 2: this planet is almost certainly tidally locked. Can you explain
Speaker 2: what that means for a planet, especially one this close
Speaker 2: to its star?
Speaker 3: Sure? Tidal locking is what happens when the gravitational pull
Speaker 3: of a large body like a star forces a smaller
Speaker 3: orbiting body, the planet, to synchronize this rotation with its orbit.
Speaker 2: Like our moon is with Earth, we only ever see
Speaker 2: one side exactly.
Speaker 3: The same principle. Since Doi five sixty one b's orbit
Speaker 3: is ten point five to six hours its rotational period,
Speaker 3: the length of its day is also ten point five
Speaker 3: six hours. The practical upshot is that one hemisphere is
Speaker 3: locked in perpetual unending daylight, while the other is trapped
Speaker 3: in eternal darkness.
Speaker 2: So one side is constantly being cooked and the other
Speaker 2: is frozen.
Speaker 3: If it were a bare, airless rock, yes, the consequences
Speaker 3: would be an unimaginable temperature gradient. The day side would
Speaker 3: be superheated to thousands of degrees, easily hot enough to
Speaker 3: vaporize rock into a magma.
Speaker 2: Ocean, a literal ocean of lava, a permanent one.
Speaker 3: Meanwhile, the night side, facing the cold of deep space,
Speaker 3: would radiate its heat away and cool down rapidly. It
Speaker 3: would likely be solid rock, perhaps even frozen solid depending
Speaker 3: on the composition.
Speaker 2: And that difference in temperature from molten to solid rock
Speaker 2: that must create some incredible physical stress.
Speaker 3: On the planet, immense thermal stress. It would likely lead
Speaker 3: the huge cracks, faults, and rampant vulcanism as the planet
Speaker 3: tries to sort of equalize that energy. It really should
Speaker 3: be a world defined by thermal catastrophe.
Speaker 2: So this is a world that should have no air,
Speaker 2: should be half molten and half frozen, and basically be
Speaker 2: tearing itself apart. But the evidence suggests it's resilient, and
Speaker 2: the key to this whole puzzle seems to lie with
Speaker 2: its parent star it does.
Speaker 3: It all comes back to the star.
Speaker 2: Our sources say the star TOI five point fifty one
Speaker 2: is a bit smaller and cooler than our Sun, but
Speaker 2: it's ancient, twice the age of the Sun. And critically,
Speaker 2: it's described as iron pore and located in the thick
Speaker 2: disk of the Milky Way. Let's unpack that because that
Speaker 2: sounds like a lot of astronomical jargon. What does that
Speaker 2: combination of traits actually tell us?
Speaker 3: Okay, so the location is hugely important. The Milky Way
Speaker 3: galaxy isn't just a uniform blob. It has structure. There's
Speaker 3: a thin disc, which is where we live, where our
Speaker 3: Sun is. It's dense, it's where most of the star
Speaker 3: formation is happening now.
Speaker 2: And then there's the thick disk right.
Speaker 3: The thick disk is an older, more diffuse, sort of
Speaker 3: puckier structure that surrounds the thin disk. Stars in the
Speaker 3: thick disk are ancient. They formed very early in the
Speaker 3: galaxy's history, probably between eight and ten billion years ago.
Speaker 3: So finding the star there is what gives us that
Speaker 3: incredible age estimate.
Speaker 2: So it's like finding a fossil from the galaxy's childhood.
Speaker 3: A perfect analogy, and a key characteristic of these fossil
Speaker 3: stars is that they are metal poor. Now, we have
Speaker 3: to be clear about what astronomers mean by metals.
Speaker 2: It's not just iron and gold right.
Speaker 3: Right to an astronomer, a metal is any element on
Speaker 3: the periodic table that isn't hydrogen or helium. Ah Okay,
Speaker 3: the early universe was made of almost nothing but hydrogen
Speaker 3: and helium. It took generations of massive stars living fast
Speaker 3: and dying young, exploding at supernovae to forge all the
Speaker 3: heavier elements and then seed the galaxy with them carbon, oxygen, silicon, iron,
Speaker 3: All of that is metal.
Speaker 2: So an iron poor star means it was borne from
Speaker 2: a cloud of gas that just hadn't been enriched with
Speaker 2: those heavier elements. Yet the galaxy wasn't fully seasoned.
Speaker 3: I guess exactly. The protoplanetary disc of gas and dust
Speaker 3: that TOI five sixty one B formed from was fundamentally
Speaker 3: deficient in those heavier elements compared to the one that
Speaker 3: our own Solar system formed from about four and a
Speaker 3: half billion years.
Speaker 2: Ago, And that has to have a direct impact on
Speaker 2: the kind of planet that can form.
Speaker 3: A huge impact. It gives us a major clue about
Speaker 3: the planet's internal structure, but more importantly, it makes the
Speaker 3: fact that it has a sustained, volatile rich atmosphere even
Speaker 3: more bizarre. Why is that because the very building blocks
Speaker 3: for a complex atmosphere and even the planet itself were
Speaker 3: just scarcer back then. So the fact that this small,
Speaker 3: ancient and highly irradiated world not only formed but held
Speaker 3: onto its atmosphere, well, it runs contrary to basically every
Speaker 3: model of planetary survival we have.
Speaker 2: So we have a theoretical model that's screaming barren, scorched rocks,
Speaker 2: screaming it. Yes, but the scientists weren't just relying on theory.
Speaker 2: They had an early clue, a piece of circumstantial evidence
Speaker 2: that something was off, and it came down to a
Speaker 2: pretty basic measurement the planet's density, right.
Speaker 3: The mass to volume ratios. The first red flag.
Speaker 2: This density calculation really became the central puzzle, the thing
Speaker 2: that kicked off this whole intensive observation campaign with the JWST.
Speaker 2: When they first measured TOI five sixty one B, they
Speaker 2: found it had a really low bulk density. Now, the
Speaker 2: sources are clear to point out it's not one of
Speaker 2: those super puff or cotton candy planets, which are almost
Speaker 2: entirely gas.
Speaker 3: No, it's definitely a rocky world. But for a super
Speaker 3: Earth with twice the mass of our planet, it was
Speaker 3: it was lighter than it should have been. The numbers
Speaker 3: just didn't quite line up with an earth.
Speaker 2: Like composition, and that discrepancy, that low density immediately presented
Speaker 2: to competing hypotheses.
Speaker 3: Right, and the team had to figure out which one
Speaker 3: was correct because they lead to radically different conclusions about
Speaker 3: the planet.
Speaker 2: Let's talk about the first one, hypothesis one.
Speaker 3: So hypothesis one goes right back to the planet's heritage
Speaker 3: where we were just discussing. The star system is ancient
Speaker 3: and iron core, so it stands to reason that the
Speaker 3: planet itself must reflect that.
Speaker 2: So its composition is just different from Earth's exactly.
Speaker 3: The lower density could be explained by more you could say,
Speaker 3: exotic interior. Perhaps it has a much smaller iron core
Speaker 3: proportionally than Earth does, and maybe it's mantle. The rocky
Speaker 3: layer is made of lower density minerals, things formed from
Speaker 3: the lighter elements that were more common in that ancient
Speaker 3: protoplanetary disk.
Speaker 2: So that's the geological explanation. The ingredients were just naturally
Speaker 2: lighter from the start.
Speaker 3: Precisely. It's a very neat and tidy explanation. It connects
Speaker 3: the formation context, the thick disk the iron pore star
Speaker 3: directly to the measurement they made. It's elegant, but.
Speaker 2: It wasn't the only possibility, And the second hypothesis is
Speaker 2: the one that really brought the JWST into the picture.
Speaker 3: Yes, hypothesis too, proposed that the low density wasn't due
Speaker 3: to the planet's core composition at all. It suggested it
Speaker 3: was an observational.
Speaker 2: Artifact, an artifact caused by what.
Speaker 3: Caused by something hiding in plain sight, a surprisingly thick atmosphere.
Speaker 2: Ah okay, how does an atmosphere make a planet seem
Speaker 2: less dense?
Speaker 3: Well, think about how we measure the size of these
Speaker 3: distant planets. We use the transit method. We watch it
Speaker 3: pass in front of its star and measure how much
Speaker 3: starlight it blocks.
Speaker 2: Right, the bigger the planet, the bigger the dip.
Speaker 3: In light, exactly. But if a planet has a thick,
Speaker 3: opaque atmosphere, what you're actually measuring is the top of
Speaker 3: that gaseous envelope, not the surface of the solid rock core.
Speaker 3: The atmosphere makes the planet appear larger and radius than
Speaker 3: it actually is, So.
Speaker 2: You've got this inflated size measurement.
Speaker 3: You've got an inflated radius, but you're using the planet's
Speaker 3: true mass, which we can measure through its gravitational tug
Speaker 3: on the star. And when you calculate density mass divided
Speaker 3: by volume, a larger volume gives you a much lower density.
Speaker 2: So the low density itself was the first major hint
Speaker 2: that this planet was wrapped in a substantial blanket of gas.
Speaker 3: It was the strongest initial hint and it was a
Speaker 3: direct challenge to all the models that said it couldn't
Speaker 3: be there.
Speaker 2: So the mission was set figure out which it was
Speaker 2: an exotic iron pore interior or a surprisingly stubborn atmosphere.
Speaker 2: How did the team use JWST to solve this? It
Speaker 2: seems incredibly difficult to isolate the light from a tiny
Speaker 2: planet right next to its blazing star.
Speaker 3: It's an immense technical challenge, and this is really where
Speaker 3: the sheer power of the jam's webspased telescope shines. They
Speaker 3: used an instrument called the near infrared spectrograph or in
Speaker 3: our spec in our spec okay, and their entire method
Speaker 3: hinged on a very long, very painstaking observation. They stared
Speaker 3: at the system for over thirty seven hours straight, focusing
Speaker 3: on a specific event called the secondary eclipse.
Speaker 2: The secondary class. That's not the transit, when the planet
Speaker 2: goes in front, that's all.
Speaker 3: That's when the planet goes behind the star. From our
Speaker 3: point of view.
Speaker 2: Okay, so what does that tell you?
Speaker 3: It tells you exactly how much light the planet itself
Speaker 3: is giving off. Think about it, Just before the eclipse,
Speaker 3: our telescope is receiving light from the star plus the
Speaker 3: light radiating from the planet's scorching hot day.
Speaker 2: Side right a combined signal.
Speaker 3: Then for a short period the planet is hidden behind
Speaker 3: the star. During that time we only get the starlight.
Speaker 3: All we have to do is subtract the star only
Speaker 3: light from the star plus planet.
Speaker 2: Light, and what's left over is the light coming only
Speaker 2: from the planet's day side.
Speaker 3: Precisely, you can isolate the planet's thermal spectrum, its heat signature.
Speaker 2: That sounds I mean, that's like trying to measure the
Speaker 2: light from a single candle flame sitting right next to
Speaker 2: a giant searchlight.
Speaker 3: That's a very good way to put it. You are
Speaker 3: trying to isolate a tiny whisper of heat energy from
Speaker 3: a background source that is thousands or even millions of
Speaker 3: times brighter.
Speaker 2: How can an instrument even do that with any accuracy?
Speaker 3: It requires incredible stability and sensitivity. In our spec is
Speaker 3: specifically optimized to look at near infrared light, and that's
Speaker 3: exactly the wavelength where a super hot surface like the
Speaker 3: day side of TOI five point sixty one B would
Speaker 3: be radiating most of its energy.
Speaker 2: So it's looking in the perfect part of the spectrum it.
Speaker 3: Is, and by observing continuously for almost four full orbits
Speaker 3: of the planet, they were just taking a single snapshot.
Speaker 3: They were accumulating data points over and over again, which
Speaker 3: allows them to build up the signal and average out
Speaker 3: the noise. They're not looking for visible light reflecting off
Speaker 3: the planet. They're measuring its thermal glow, the infrared heat,
Speaker 3: which is a much more direct way to measure its temperature.
Speaker 2: A fascinating look at how these observatories actually work. But okay,
Speaker 2: let's get to the results. What did that meticulous measurement show.
Speaker 2: Here's where it gets really interesting. What was the number?
Speaker 3: The proof was in the numbers, absolutely and it came
Speaker 3: down to a massive discrepancy between what the temperature should
Speaker 3: have been and what they actually observed.
Speaker 2: Okay, so what was the prediction if TOI five point
Speaker 2: sixty one B was just a bare airless rock.
Speaker 3: The thermal models, assuming it's a perfect black body, just
Speaker 3: absorbing and reradiating all that stellar energy, predicting a day
Speaker 3: side temperature approaching a staggering forty nine hundred degrees here
Speaker 3: night nine hundred degrees or about twenty seven hundred degrees celsius.
Speaker 2: I can't even comprehend that that's far hotter than the
Speaker 2: melting point of most rocks. You'd have that magma ocean
Speaker 2: we talked.
Speaker 3: About, guaranteed it's hard enough to melt and boil steel
Speaker 3: almost instantly. That was a baseline prodution for a dead
Speaker 3: airless world.
Speaker 2: So what did JWST actually see?
Speaker 3: The NIR spectata revealed that the day side temperature was
Speaker 3: significantly cooler. How much cooler The measurement came in closer
Speaker 3: to three to two hundred degrees fahrenheit or about eighteen
Speaker 3: hundred celsius.
Speaker 2: Wait, a drop of seventeen hundred degrees fahrenheit.
Speaker 3: Yes, a massive, massive difference. It's more than nine hundred
Speaker 3: degrees celsius cooler than it should be. There's simply no
Speaker 3: way for a bare rock to be that cool under
Speaker 3: them atradiation.
Speaker 2: So something has to be getting in the way, Something
Speaker 2: has to be distributing that heat exactly.
Speaker 3: That significant cooling effect absolutely must be caused by something substantial,
Speaker 3: and the only plausible candidate is a thick atmosphere that's
Speaker 3: actively regulating the planet's temperature.
Speaker 2: So it's not just that an atmosphere is there, it's
Speaker 2: that it's actively working. It's adynamic system.
Speaker 3: It has to be A simple thin layer of gas
Speaker 3: wouldn't be enough. You need complex processes to explain that
Speaker 3: level of cooling.
Speaker 2: What about other explanations. Could something else be moving the
Speaker 2: heat around? What if the magma ocean itself was circulating
Speaker 2: carrying heat to the night side.
Speaker 3: That's a great question, and the team considered it. A
Speaker 3: magma ocean could certainly circulate some heat, but without an
Speaker 3: atmosphere to trap that heat and move it efficiently, the
Speaker 3: night side would still likely cool down so much that
Speaker 3: the rock would solidify.
Speaker 2: Ah, so you'd have a solid barrier on the night side,
Speaker 2: which would limit how much heat could flow from the
Speaker 2: day side.
Speaker 3: It would limit the flow, Yes, the circulation would be inefficient.
Speaker 3: You also might get a very thin atmosphere of vaporized
Speaker 3: rock silicate vapor. But again, a thin layer like that
Speaker 3: just doesn't provide the kind of global cooling effect that
Speaker 3: was observed. It can't explain a seventeen hundred degree temperature drop.
Speaker 2: So those simpler explanations just don't fit the data.
Speaker 3: They don't. As a researcher said, we really need a thick,
Speaker 3: vault little rich atmosphere to explain all the observations.
Speaker 2: Volatile rich meaning gas is light. Yeah, what are we
Speaker 2: talking about here?
Speaker 3: We're talking about things that are gases at lower temperatures
Speaker 3: than rock, water, vapor, carbon dioxide, maybe even oxygen or methane,
Speaker 3: though that's less likely these temperatures. Volatiles the stuff atmospheres
Speaker 3: are made of.
Speaker 2: And this thick, volatile rich atmosphere would have several ways
Speaker 2: of cooling that day side down.
Speaker 3: That's right. The model suggest at least three key cooling
Speaker 3: mechanisms are probably at play here.
Speaker 2: Okay, what's the first one.
Speaker 3: The first and maybe the most intuitive is wind, really
Speaker 3: really strong winds.
Speaker 2: Winds on a world that hot with a magma ocean.
Speaker 3: Exactly the extreme temperature difference between the super hot day
Speaker 3: side and the cooler night side would drive incredibly powerful
Speaker 3: atmospheric circulation. These winds would pick up heat from the
Speaker 3: scorching day side and physically transport it over to the
Speaker 3: night side.
Speaker 2: So it's like a planetary scale air conditioner. It's just
Speaker 2: moving the heat around the globe, preventing it from building
Speaker 2: up in one spot.
Speaker 3: That's the perfect way to think about it. It lowers
Speaker 3: the maximum temperature on the day side by spreading the
Speaker 3: energy out more evenly.
Speaker 2: Okay, so that's one. What's the second cooling effect?
Speaker 3: The second is gas absorption. Those volatile gases we mentioned water,
Speaker 3: carbon dioxide, things like that are very good at absorbing
Speaker 3: near infrared light, the.
Speaker 2: Very light that JWST is looking for the very same.
Speaker 3: So the hot surface is radiating this infrared light, but
Speaker 3: before that light can escape into space and reach our telescope,
Speaker 3: the atmosphere absorbs some of it. From our perspective, the
Speaker 3: planet just looks dimmer and therefore colder than it actually
Speaker 3: is at the surface.
Speaker 2: So the atmosphere acts like a filter, blocking some of
Speaker 2: the heat signature it does.
Speaker 3: It's another piece of the puzzle that contributes to that
Speaker 3: lower observed temperature, and the third mechanism. The third possibility
Speaker 3: is clouds.
Speaker 2: Clouds on a lava world. What would they even be
Speaker 2: made of?
Speaker 3: Well, not water, obviously, but you could potentially have clouds
Speaker 3: made of silicate mineral, tiny droplets of vaporized rock that
Speaker 3: condense at higher, cooler altitudes.
Speaker 2: And if those clouds are bright, If they're bright.
Speaker 3: They would act just like clouds on Earth. They would
Speaker 3: reflect a significant amount of the incoming starlight back into
Speaker 3: space before it ever even has a chance to heat
Speaker 3: the surface. It's another way to cool a whole system down.
Speaker 2: So you have this three pronged defect winds moving heat,
Speaker 2: gas absorbing heat, and clouds reflecting heat, and together they
Speaker 2: can account for that seventeen hundred degree drop.
Speaker 3: That's the model that best fits the data we have
Speaker 3: so far, a very active, very complex atmospheric.
Speaker 2: System, which brings us to the biggest question of all,
Speaker 2: the one that started this whole thing. How can a
Speaker 2: small planet this close to its star, in this much
Speaker 2: radiation hold onto any atmosphere, let alone a thick and
Speaker 2: complex one. It should have been gone billions of years ago.
Speaker 3: And this is I think the most profound part of
Speaker 3: the discovery. The answer seems to be the concept of equilibrium.
Speaker 2: Equilibrium, meaning it's not just hold on to its original atmosphere,
Speaker 2: but it's being.
Speaker 3: Replaced, it's being constantly replenished. The lead author of one
Speaker 3: of the studies introduced this fantastic analogy. They said, this
Speaker 3: planet is likely much much more volatile rich than Earth.
Speaker 3: They described it as and this is a quote, really
Speaker 3: like a wet lava ball.
Speaker 2: A wet lava ball. That is an incredible image. What
Speaker 2: does that mean?
Speaker 3: It means the planet's interior, its magma, is saturated with
Speaker 3: dissolved gases, the same volatiles that make up the atmosphere.
Speaker 3: And what's happening is a dynamic cycle.
Speaker 2: A cycle.
Speaker 3: Okay, so yes, gases at the top of the atmosphere
Speaker 3: are constantly escaping into space. The star is still blasting
Speaker 3: them away. That part of the old model is still true.
Speaker 3: But at the same time, the intense heat is causing
Speaker 3: gases to constantly come out of the magma ocean to
Speaker 3: feed the atmosphere from below. It's called outgassing.
Speaker 2: So it's losing atmosphere, but it's also making new atmosphere
Speaker 2: at the same time.
Speaker 3: Precisely, and it's even more complex. The thinking is that
Speaker 3: the magma ocean is all so sucking some gases back
Speaker 3: into the planet's interior. So you have this three way exchange,
Speaker 3: gas escaping to space, gas out gassing from the magma,
Speaker 3: and gas being reabsorbed by the magma.
Speaker 2: A constant recycling process.
Speaker 3: A dynamic equilibrium. The atmosphere isn't a static leftover from
Speaker 3: the planet's formation. It's a feature that is being actively maintained, recycled,
Speaker 3: and replenished by the planet's own geology moment by moment.
Speaker 3: That is how it survives.
Speaker 2: That completely changes the picture. It's not a question of
Speaker 2: how long a planet can keep its atmosphere, but whether
Speaker 2: it has the right internal ingredients to continuously make one.
Speaker 3: You've hit it exactly, and that's where the planet's origins
Speaker 3: become so important again.
Speaker 2: Right, Let's connect the dots back to that ancient iron
Speaker 2: poor star. How does the planet's formation in the early
Speaker 2: universe relate to it being this wet lava ball.
Speaker 3: Well, remember that star formed when the universe was younger
Speaker 3: and less chemically enriched. The protoplanetary disc was pour in
Speaker 3: heavy metals like iron. But it may have been comparatively
Speaker 3: rich in other things.
Speaker 2: It volatiles, water carving exactly.
Speaker 3: It's possible that planets forming in that environment incorporated a
Speaker 3: much higher fraction of volatile materials into their bulk composition
Speaker 3: from the very beginning. The building blocks themselves might have
Speaker 3: been sagier for lack of a better word.
Speaker 2: So TOI five sixty one, B's composition isn't just an oddity.
Speaker 2: It's likely representative of the kinds of planets that formed
Speaker 2: when the universe was relatively young.
Speaker 3: That's the really exciting implication. And it fits with that
Speaker 3: initial density puzzle. The low density, the likely smaller iron core,
Speaker 3: and the less dense mantle. All that makes perfect sense
Speaker 3: if the planet formed in an environment that was chemically
Speaker 3: different from our own.
Speaker 2: So what does this all mean? Let me see if
Speaker 2: I can summarize the aha moment here for you. Go
Speaker 2: for it. We found a planet that proves that even
Speaker 2: under the most hostile ultrahot conditions imaginable, if a world
Speaker 2: forms with enough volatile material packed into its interior, if
Speaker 2: it's a wet lava ball, it can establish this incredible
Speaker 2: dynamic equilibrium, a cycle of outgassing and reabsorption that allows
Speaker 2: it to maintain a thick, protective atmospheric blanket indefinitely as
Speaker 2: a perfect summary, and that just it completely expands the
Speaker 2: range of possibilities for where atmospheres can survive. We used
Speaker 2: to look at planets like this and just write them
Speaker 2: off as cinders.
Speaker 3: They were written off. Yeah, they were considered the worst
Speaker 3: possible places to look for atmospheres, And this discovery tells
Speaker 3: us we were wrong. It suggests there might be a
Speaker 3: whole class of resilient, geologically active worlds out there that
Speaker 3: we've been completely ignoring.
Speaker 2: It's worth mentioning the scale of this research too. This
Speaker 2: wasn't just a quick look.
Speaker 3: Oh not at all. This result is just the first
Speaker 3: from a huge JWST program General Observers Program thirty eight
Speaker 3: to sixty. It involved that very long thirty seven hour
Speaker 3: observation we talked about, and the team is still analyzing
Speaker 3: the full data set.
Speaker 2: What are they hoping to find in the rest of
Speaker 2: that data.
Speaker 3: The next big step is to try and map the
Speaker 3: temperature all the way around the planet. They want to
Speaker 3: measure the temperature of the night side as it rotates
Speaker 3: back into.
Speaker 2: And that would tell them how efficient that heat transport
Speaker 2: really is exactly.
Speaker 3: It would put real constraints on those wind speed models,
Speaker 3: and they're also digging deeper into the spectrum of the
Speaker 3: atmosphere itself. The goal is to try and pinpoint the
Speaker 3: precise chemical composition. Is mostly carbon dioxide? Is there water vapor?
Speaker 3: Knowing the specific gases will tell us even more about
Speaker 3: the planet's geology and formation.
Speaker 2: So there's still a lot more to come from this
Speaker 2: one world.
Speaker 3: We're just scratching the surface.
Speaker 2: Let's just recap the absolute key findings. Then we have
Speaker 2: TOI five sixty one B a scorching super earth orbiting
Speaker 2: its ancient star every ten and a half hours. A
Speaker 2: place where we expected to find a bare rock heated
Speaker 2: to nearly five thousand degrees.
Speaker 3: Fahrenheit before picture.
Speaker 2: Yes, Instead we find a world that is over seventeen
Speaker 2: hundred degrees cooler than expected, shielded by a thick atmosphere
Speaker 2: that it actively maintains through dynamic equilibrium with a volatile,
Speaker 2: rich magma ocean below.
Speaker 3: The wet lovea ball in action.
Speaker 2: It's just it's a phenomenal discovery. I like the quote
Speaker 2: from the lead author. You want a tesca that you
Speaker 2: flagged for us? She said, what's really exciting is that
Speaker 2: this new data set is opening up even more questions
Speaker 2: than it's answering.
Speaker 3: And that is always the sign of a truly great
Speaker 3: discovery In science. It's not about closing the book. It's
Speaker 3: about realizing the book is much much larger than you
Speaker 3: ever thought of us.
Speaker 2: So we always like to end by leaving you the
Speaker 2: listener with a final provocative thought, something to molover. What's
Speaker 2: the big takeaway here that we should be thinking about.
Speaker 3: Well, I think it comes back to the age of
Speaker 3: this system. This planet in its star formed when the
Speaker 3: universe was younger, when it was less chemically enriched with
Speaker 3: the heavy elements we see around us today.
Speaker 2: Right, It's a relic from an earlier cosmic era.
Speaker 3: It is so if a world like this, an ancient
Speaker 3: world born in a metal poor environment, can not only
Speaker 3: form with enough volatiles, but can then maintain a complex
Speaker 3: atmospheric cycle for ten billion years under the most extreme conditions,
Speaker 3: what does that imply for all the other older exoplanets
Speaker 3: out there. Think about the sheer number of plant's orbiting
Speaker 3: ancient stars in the thick disk or in globular clusters
Speaker 3: that we might have overlooked. How many of them have
Speaker 3: we dismissed as bare rock candidates where they might actually
Speaker 3: be hosting these incredibly resilient dynamic systems.
Speaker 2: It suggests there could be a huge hidden population of
Speaker 2: worlds with atmospheres where we never thought to look.
Speaker 3: It forces us to reconsider what makes a world survivable,
Speaker 3: not for life, perhaps, but for its own atmosphere. The
Speaker 3: universe might be far more capable of creating and sustaining
Speaker 3: these kinds of worlds than our models ever gave it
Speaker 3: credit for. And that's something for you to think about
Speaker 3: as you continue to explore the cosmos.
Speaker 2: A fascinating thought to end on. It's a reminder that
Speaker 2: every new data point can completely change our perspective. Thanks
Speaker 2: for joining us for this deep dive school, stays Sai