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 curious minds. Today, we're looking at something pretty radical,
Speaker 2: overturning a decade's old idea about Mars. Forget the notion
Speaker 2: of just a you know, a fully liquid, maybe dying
Speaker 2: heart beneath that dusty red surface. New seismic data this
Speaker 2: is from NASA's Insight mission. It reveals Mars holds a
Speaker 2: secret a solid core, and it's shockingly similar to Earth's,
Speaker 2: which is well, it's a discovery that completely rewrites the history,
Speaker 2: the really violent history of the red planet and its
Speaker 2: lost oceans.
Speaker 3: Yeah. What's truly remarkable here is how our understanding of
Speaker 3: Mars just keep evolving. It's constantly pushing the boundaries of
Speaker 3: what we thought was possible. You know, it forces us
Speaker 3: to reevaluate these long held assumptions we've had. We know,
Speaker 3: Mars today is well a cold, dry, seemingly desolate world,
Speaker 3: like a frozen desert basically, Yet the evidence that's been
Speaker 3: building up it strongly suggests a very different past, one
Speaker 3: that held this compelling promise of well abundant liquid water
Speaker 3: and perhaps you know, maybe even the potential for life right,
Speaker 3: and the key to unlocking this huge mystery, it turns out,
Speaker 3: lies hundreds of kilometers down way beneath its now dusty,
Speaker 3: arid surface.
Speaker 2: Yeah, for years, Mars has felt like this colossal planet
Speaker 2: sized cold case, hasn't it? How did it go from
Speaker 2: being potentially watery, maybe even vibrant, to the parched desert
Speaker 2: it is today. It's a question that's really driven decades
Speaker 2: of exploration absolutely and today are let's call them our
Speaker 2: forensic team, the scientists working with the Insight Mission. They
Speaker 2: finally cracked a really crucial piece of that puzzle. It's
Speaker 2: dramatically reshaping our understanding of Mars interior. We're talking incredible
Speaker 2: new insights from seismic studies. They literally offer us a
Speaker 2: peak into its innermost secrets, like a planetary autopsy report.
Speaker 3: Almost, And this raises a really important question for all
Speaker 3: of us. I think, what can the very core of
Speaker 3: a planet actually tell us about its entire history, it's trajectory,
Speaker 3: it's ultimate fate. We'll be looking at how these recent
Speaker 3: observations have not just refined, but really significantly deepened our models,
Speaker 3: suggesting that Mars might be far more like Earth deep
Speaker 3: down than we previously believed. And this is more than
Speaker 3: just geology, you know, it's a profound story planetary evolution,
Speaker 3: the delicate balance of magnetic fields, and the incredibly specific
Speaker 3: conditions that are required for a world to remain hospitable,
Speaker 3: to hold on to its life giving potential over well
Speaker 3: cosmic time scales.
Speaker 2: So our mission today as we dive into this is
Speaker 2: really to uncover the secrets of Mars's core, understand why
Speaker 2: it's structure and its history matters so much to the
Speaker 2: planet's past and maybe its future, and so to see
Speaker 2: how science, like a you know, a persistent detective, painstakingly
Speaker 2: builds knowledge step by careful steps. So, yeah, prepare to
Speaker 2: have your assumptions about the Red planet challenged.
Speaker 3: Well. Trace this fascinating journey of scientific discovery right from
Speaker 3: the initial hypotheses, which were often based on remote observations,
Speaker 3: you know, looking from orbit to the latest and most
Speaker 3: precise seismic measurements from insight. And we'll try to connect
Speaker 3: these seemingly abstract, kind of complex details to the grand
Speaker 3: sweeping narrative of Mars's really dramatic transformation. It really is
Speaker 3: a planetary detective story.
Speaker 2: Okay, So let's start with the Mars. We think we know,
Speaker 2: the one we see today when we look up at
Speaker 2: the night sky see that unmistakable red dot, or when
Speaker 2: we see those amazing images beamed back by the rovers,
Speaker 2: what comes to mind? I mean, it's a vast chili desert, right,
Speaker 2: that's the image most of us have precisely.
Speaker 3: Yeah, you've captured it perfectly. The Mars we observe today
Speaker 3: is characterized by an extremely thin atmosphere, really thin. It's
Speaker 3: mostly carbon dioxide, something like ninety five percent. And this
Speaker 3: thin on belowe it offers very little protection from solar radiation.
Speaker 3: The surface pressure is less than one percent of Earth's
Speaker 3: at sea level, just.
Speaker 2: Incredibly wow, less than one percent.
Speaker 3: Yeah, And temperatures well, they rarely if ever get above freezing,
Speaker 3: often plunging way down to minus sixty degrees celsius or
Speaker 3: even colder at the poles. And the almost complete lack
Speaker 3: of significant stable liquid water on the surface. That's one
Speaker 3: of its most defining features right now. It is, by
Speaker 3: all accounts, a very harsh place inhospitable, a true frozen desert.
Speaker 2: And you think about those pictures, those iconic images from
Speaker 2: the rovers, spirit, opportunity, curiosity, perseverance. You see those dusty,
Speaker 2: rust colored planes stretching out forever, barren, rocky landscapes, those clear,
Speaker 2: often kind of salmon pink skies, sometimes with those swirling
Speaker 2: dust devils. It's got this men's geological beauty for sure.
Speaker 2: That absolutely not a place you'd picture taking a swim
Speaker 2: right or finding a river, seeing oceans. It feels like
Speaker 2: a world strip bear of the very things that make
Speaker 2: Earth so well alive. But that's not the complete picture,
Speaker 2: is it not? By a long shot. That stark reality
Speaker 2: of Mars today actually makes the evidence for past water
Speaker 2: even more compelling, doesn't it. It really underlines the sheer scale
Speaker 2: of the change the planet went through. There's a huge
Speaker 2: amount of compelling, really undeniable evidence telling a very different
Speaker 2: story about Mars's past, a time when it was a
Speaker 2: very different kind of world.
Speaker 3: Indeed, Yeah, what's truly remarkable is the overwhelming geological evidence
Speaker 3: meticulously gathered over decades by orbiters and rovers like Curiosity
Speaker 3: and Perseverance. This evidence suggests that liquid water once flowed freely, abundantly,
Speaker 3: even and perhaps for long periods across the Martian surface.
Speaker 3: We're talking about conditions that were well, incredibly far more
Speaker 3: hospitable than anything we see today, a Mars that would
Speaker 3: be honestly unrecognizable to us, maybe resembling a young.
Speaker 2: Earth, a young or wow. So what kind of evidence
Speaker 2: are we talking about specifically?
Speaker 3: Well, comes in many forms, and each one is like
Speaker 3: a powerful clue, really undeniable. For instance, we found numerous
Speaker 3: dry lake beds. These are expansive basins that clearly once
Speaker 3: held standing water, and you see ancient shorelines, delta structures,
Speaker 3: sedimentary fans like river deltas exactly. I consider Jeseral Crater
Speaker 3: where perseverances right now. The images show these intricate river
Speaker 3: deltas very much like say the Mississippi delta here on Earth.
Speaker 3: This is where river once flowed into a vast lake,
Speaker 3: depositing sediments over potentially millions of years. And within those
Speaker 3: ancient sediments, scientists have found specific minerals, things like clays
Speaker 3: and sulfates, phyllosilicates like smectite chlorite, or evaporates like gypsum jerriscite.
Speaker 3: These are minerals that could only have formed if liquid
Speaker 3: water was present for a long time. They're not subtle hints,
Speaker 3: they're definitive chemical signatures, like a chemical fingerprint of past
Speaker 3: water locked away for billions of years.
Speaker 2: Okay, so dry lakes, specific minerals.
Speaker 3: What else, Well, beyond that, we see these dramatic valley
Speaker 3: networks etched into the landscape. They're not just random cracks,
Speaker 3: intricate branching systems, really similar in their shape their morphology
Speaker 3: to river systems on Earth. Think of those dendritic patterns
Speaker 3: you see in aerial photos of the Amazon Basin, for example,
Speaker 3: right like tree branches spreading out precisely. And these aren't
Speaker 3: just small channels. They're often kilometers wide, hundreds of meters deep.
Speaker 3: They're unmistakable evidence carved by the relentless flow of ancient rivers,
Speaker 3: long lived rivers, not just you know, flash floods. And
Speaker 3: then there are the sedimentary layers. You can see them
Speaker 3: in canyon walls like in valasmarneras or exposed in crater rims.
Speaker 3: These finely stratified deposits laid down layer upon layer over
Speaker 3: vast time scales. There are textbook examples of deposition and
Speaker 3: standing bodies of water to light sediments settle in lakes
Speaker 3: or seas here on Earth, it indicates a long sustained
Speaker 3: period of water activity. All of this taken together piints
Speaker 3: this vivid, irrefutable picture of a world that was once
Speaker 3: rich in water.
Speaker 2: So yeah, this overwhelming evidence that really begs the question,
Speaker 2: doesn't it. How could a planet now so incredibly arid,
Speaker 2: so seemingly lifeless, have once supported such an abundance of
Speaker 2: liquid water. What allowed for that much thicker atmosphere and
Speaker 2: a milder climate, the conditions that were clearly needed for
Speaker 2: surface water to exist. It's just such a radical transformation,
Speaker 2: a monumental shift. What drove such a huge change?
Speaker 4: Okay, To really get a handle on Mars's incredible transformation
Speaker 4: from potentially watery to the col dry world we see,
Speaker 4: we need to understand something absolutely vital about our own planet. First, Earth,
Speaker 4: It's internal engine, it's heart, you could say. So, if
Speaker 4: we're trying to figure out Mars's big shift, we really
Speaker 4: need to start with Earth, don't we. I mean, why
Speaker 4: is our internal engine, so incredibly good at protecting our
Speaker 4: atmosphere and keeping life going.
Speaker 3: Yeah, well it connect this to the bigger picture, the
Speaker 3: whole idea of planetary habitability. A key property of Earth's
Speaker 3: remarkable ability to sustain life comes directly from its core.
Speaker 3: Our planet has what we call a differentiated core. There's
Speaker 3: a solid inner core mostly iron and nickel, and that's
Speaker 3: surrounded by a churning, swirling liquid outer core, also mainly
Speaker 3: iron and nickel, but mixed with some lighter elements like
Speaker 3: soul for an oxygen. It's this dynamic internal structure that's
Speaker 3: absolutely critical for generating or its global magnetic field.
Speaker 2: Okay, solid inner, liquid outer.
Speaker 3: And this specific arrangement is what drives the geodynamo effect. Essentially,
Speaker 3: you have convexing currents within that liquid outer layer. Think
Speaker 3: of like boiling water, but with molten metal. These currents
Speaker 3: are driven by heat escaping from the salt inner core
Speaker 3: as it cools and crystallizes, and also by the planet's rotation.
Speaker 3: The Coriolis effects stirs things up, and this whole process
Speaker 3: generates a powerful expanse of magnetic field. This field stretches
Speaker 3: way out into space, forming this invisible protective bubble around
Speaker 3: our entire planet. We call it the magnetosphere. It's a
Speaker 3: truly amazing self sustaining system.
Speaker 2: So it's like an invisible shield. That's a good way
Speaker 2: to think about it constantly deflecting all this harmful stuff
Speaker 2: from the sun, charged particles exactly.
Speaker 3: It deflects harmful charged particles that are constantly blasted out
Speaker 3: by the Sun, especially during solar flares and chronal mass ejections.
Speaker 3: These solar winds, as they're called, are incredibly energetic streams
Speaker 3: of protons and electrons, and without that magnetospheric shield, they
Speaker 3: would just relentlessly strip away our atmosphere over geological time.
Speaker 2: Like a sand blaster.
Speaker 3: Yeah, that's a good analogy. Much like a powerful sand
Speaker 3: blaster eroding rock. It's this continuous, silent battle happening way
Speaker 3: above our heads. The magnetosphere acts like a bouncer, basically
Speaker 3: redirecting these high energy particles around Earth. Without this magnetic protection,
Speaker 3: our atmosphere, and along with it, the conditions for life
Speaker 3: would slowly but surely vanish. It's also why we get
Speaker 3: the auroras, the northern and Southern lights, that some of
Speaker 3: those deflected particles interacting with our atmosphere near the poles,
Speaker 3: a beautiful side effect of our planet's shield.
Speaker 2: Okay, that makes sense. So with that essential understanding of
Speaker 2: Earth's shield in mind, what about Mars. Does it have
Speaker 2: a similar life preserving magnetic field today? Because I mean,
Speaker 2: if it doesn't, that immediately points to a very different situation,
Speaker 2: doesn't it maybe one vulnerability of loss currently, No.
Speaker 3: It doesn't. Mars utterly lacks a global magnetic field today,
Speaker 3: certainly nothing like Earth's. This is a critical difference and
Speaker 3: a major reason why Mars is the cold, dry world
Speaker 3: we see now. However, and this is a really crucial
Speaker 3: piece of the puzzle. The evidence points to a very
Speaker 3: different pass from Mars too, from residual magnetization found embedded
Speaker 3: in the Martian crust. Essentially, you have rocks on the
Speaker 3: surface that still hold a Foffel magnetic signature. This signature
Speaker 3: dates back to when they first formed and cooled down
Speaker 3: billions of years ago in the presence of an active
Speaker 3: magnetic field. Scientists are quite confident that Mars did once
Speaker 3: possess such a global field.
Speaker 2: So it had a shield too early on, it.
Speaker 3: Seems so orbiting spacecraft like Mars Global surveyor actually mapped
Speaker 3: these magnetic anomalies in the crust. They confirmed that an
Speaker 3: ancient dynamo was active, likely for maybe the first billion
Speaker 3: years or so of Mars's history. And this ancient field
Speaker 3: was probably generated by a core structure similar to Earth's,
Speaker 3: meaning it likely had a soltid inner core and a
Speaker 3: liquid outer core capable of driving that dynamo.
Speaker 2: Okay, so it had one, but lost it. What are
Speaker 2: the implications of that loss?
Speaker 3: They're profound, truly profound. It marks a pivotal moment in
Speaker 3: Mars's story. Scientists generally hypothesize that the eventual loss of
Speaker 3: this magnetic field was a critical turning point, perhaps the
Speaker 3: critical turning point. Without that protective shield, the relentless solar
Speaker 3: wind would have had direct, unimpeded access to Mars's ancient, much.
Speaker 2: Thicker atmosphere, right, no more bouncer.
Speaker 3: Exactly, over millions, hundreds of millions of years, this energetic
Speaker 3: bombardment would have stripped that atmosphere away, particle by particle
Speaker 3: through processes like sputtering where particles get knocked off and
Speaker 3: ion pickup, where atmospheric gases get carried away by the
Speaker 3: solar wind. Think of it like a constant slow leak
Speaker 3: into space. This atmospheric loss, in turn, would have led
Speaker 3: directly to the rapid and irreversible loss of surface liquid water.
Speaker 3: As the atmospheric pressure dropped, water just couldn't stay liquid
Speaker 3: on the surface anymore. It would either freeze or subtlee
Speaker 3: may turn directly into gas and escape into space, or
Speaker 3: maybe retreat underground. It's this cascading chain of events starting
Speaker 3: deep inside the planet with the dying dynamo that ultimately
Speaker 3: led to the barren landscape we see today.
Speaker 2: Wow, so it all comes back to the core. This
Speaker 2: really raises that central question. Then, what exactly happened to
Speaker 2: Mars's internal engine? What switched off that planetary dynamo? What
Speaker 2: turned Mars from potentially vibrant and watery into the desert?
Speaker 2: It is now that's the core mystery, isn't it. And
Speaker 2: to answer that, we couldn't just look at the surface anymore.
Speaker 2: We had to go deeper, which is precisely why missions
Speaker 2: like Insight were conceived right precisely.
Speaker 3: Yeah, while missions like NASA's amazing Rover, Spirit, Opportunity, Curiosity,
Speaker 3: Perseverance have been fantastic surface geologists, you know, analyzing rocks
Speaker 3: and soil and orbiters like esay's exomrs trace gas orbit
Speaker 3: or study the water cycle, and NASA has made an
Speaker 3: end look specifically at an atmospheric loss. A fundamentally different
Speaker 3: kind of mission was needed to probe that core question,
Speaker 3: the question about the planets deep into We needed to listen, not.
Speaker 2: Just look, and that mission was NASA's Insight Lander. It
Speaker 2: touched down quite incredibly back in November twenty eighteen, landed
Speaker 2: in a region called Elysium Planitia, chosen because it's relatively
Speaker 2: flat geologically quiet, which is ideal for its sensitive instruments.
Speaker 2: Its primary goal, really groundbreaking, was to study seismic activity
Speaker 2: marsquakes as we call them. The aim was to reveal
Speaker 2: for the very first time the planet's internal structure, its crust,
Speaker 2: its mantle, and crucially its core. Insight listened patiently to
Speaker 2: Mars for four years, making its last contact in December
Speaker 2: twenty twenty two. Sadly its solar panels got too dusty
Speaker 2: to keep it powered. But it's data that continues to
Speaker 2: revolutionize our understanding. It's this treasure trope scientists are still
Speaker 2: digging through. Okay, so here's where it gets really interesting.
Speaker 2: In twenty twenty one, there was this seminal paper, a
Speaker 2: truly landmark study that came out of the Insight mission
Speaker 2: led by Simon Staylor and his colleagues. This paper gave
Speaker 2: us the very first direct look, the first robust measurement
Speaker 2: of Mars core. So, after all that anticipation, all that listening,
Speaker 2: what did they actually find? What was the initial verdict
Speaker 2: on Mars depth secret.
Speaker 3: Well, using that invaluable data from the marsquakes, those faint
Speaker 3: rumbles and tremors deep inside the planet, Stealer's team analyzed
Speaker 3: how the seismic waves traveled through Mars. Think of it
Speaker 3: like shouting into a canyon and timing the echoes. Different
Speaker 3: materials inside the planet reflect and transmit seismic waves differently. Okay,
Speaker 3: So by precisely timing how these marsquake echoes, specifically the
Speaker 3: Pea waves which are compressional waves and s ways the
Speaker 3: Shearer waves traveled from the quake's origin through the crust,
Speaker 3: the mantle, down into the core, maybe reflecting off internal boundaries,
Speaker 3: and then finally traveling back up to inside supersensitive seismometer
Speaker 3: called SACE, they could literally map the internal layers like
Speaker 3: a planetary sonogram. It was the first time we ever
Speaker 3: directly heard Mars's internal structure. Incredible, So what did that
Speaker 3: first map show? What did the core look like in
Speaker 3: that twenty twenty one study, Right, So, their in depth analysis,
Speaker 3: based on about a dozen of the larger marsquakes they
Speaker 3: had recorded by then, revealed a few key things. Some
Speaker 3: were a bit surprising at the time. They modeled a
Speaker 3: core with just a single liquid layer, basically a big
Speaker 3: molten ball of metal, and this core was surprisingly large.
Speaker 3: They estimated its radius at about eighteen hundred kilometers, which
Speaker 3: is roughly half of Mars's total radius, quite big for
Speaker 3: a planet Mars.
Speaker 2: Off the radius wow Yeah.
Speaker 3: And furthermore, it turned out to be less dense than
Speaker 3: you'd expect for a purely iron nickel core like Earth's.
Speaker 3: Is mostly this density deficit, which they inferred from how
Speaker 3: fast the seismic waves traveled through it, strongly suggested it
Speaker 3: was rich in lighter elements, things like sulfur or oxygen
Speaker 3: carbon maybe hydrogen mixed in with the iron and nickel.
Speaker 2: And why is that important for lighter elements.
Speaker 3: Well, those lighter elements significantly affect the core's melting temperature
Speaker 3: if they lower it. That makes it much more likely
Speaker 3: for the core to stay liquid for longer, rather than
Speaker 3: solidifying quickly as the planet cools down over billions of years.
Speaker 3: So this was a crucial insight. It potentially explained how
Speaker 3: Mars might have kept a liquid core and maybe a
Speaker 3: dynamo going for some time. And though it's smaller than.
Speaker 2: Earth, okay, so large liquid less dens full of lighter elements,
Speaker 2: did they say anything about a solid inner core like Earth's.
Speaker 3: That's a really crucial detail from Staleler's paper, and it
Speaker 3: shows how careful science is. They did not explicitly rule
Speaker 3: out the possibility of a solid inner core. The authors
Speaker 3: themselves meticulously stated in the paper that the signal strength
Speaker 3: from the data they had at that time, and the
Speaker 3: specific types of seismic waves they could confidently analyze were
Speaker 3: simply not robust enough, not clear enough. They couldn't definitively
Speaker 3: identify the faint signals you'd expect from seismic waves crossing
Speaker 3: an intercore boundary. So it's an excellent first measurement, truly
Speaker 3: a monumental achievement, but they explicitly acknowledged its limitations and
Speaker 3: left room for further discoveries. It's at the stage, you know,
Speaker 3: waiting for more data or better techniques to perhaps see deeper.
Speaker 2: Right, And science is truly a journey, isn't it? Not
Speaker 2: just one destination. So while Staler's work was absolutely monumental,
Speaker 2: a groundbreaking first look, the story of Mars core or
Speaker 2: as you said, didn't stop there. Just recently, new even
Speaker 2: more refined results came out. This was from Hwixingbe and
Speaker 2: colleagues published in the journal Nature. And this took our
Speaker 2: understanding to a whole new level, didn't it. What did
Speaker 2: they uncover that was so significant building on that initial
Speaker 2: foundation laid by Staler's team.
Speaker 3: Yeah, this is a fantastic example of scientific progress in action.
Speaker 3: You see one study building directly on the previous one
Speaker 3: and also the power of persistent, clever data analysis. This
Speaker 3: latest study by Biling colleagues, they leveraged additional insight data
Speaker 3: data collected over a longer period after Staler's first analysis,
Speaker 3: So that meant a larger catalog of Mars quakes to
Speaker 3: work with, including some that were perhaps deeper or more energetic,
Speaker 3: sending clearer signals through the core. Okay, more data, more data, yes,
Speaker 3: But crucially they also employed some novel and highly sophisticated
Speaker 3: data analysis techniques, new ways of processing the signals. By
Speaker 3: carefully selecting specific types of seismic events, ones that happened
Speaker 3: at just the right distances from d site to maximize
Speaker 3: the chance of detecting faint reflections from deep within, and
Speaker 3: then expertly extracting an incredibly weak signal from what was
Speaker 3: often quite a lot of instrument noise, they managed something remarkable.
Speaker 3: It was like seismological detective work, filtering out all the
Speaker 3: background chatter to finally hear the planet's deepest whispers clearly.
Speaker 2: And what did those whispers tell them? What was the
Speaker 2: key finding?
Speaker 3: Their key finding was unambiguous. They identified the clear presence
Speaker 3: of a solid layer within the liquid Martian core. This
Speaker 3: wasn't just a subtle hint. It was the distinct solid
Speaker 3: inner core, and they even estimated its radius at approximately
Speaker 3: six hundred and ten kilometers.
Speaker 2: Six hundred and ten kilometers. How does that compare to
Speaker 2: the overall core size.
Speaker 3: Well, if the total core radius is around eighteen hundred kilometers,
Speaker 3: then six hundred and ten kilometers is a substantial fraction,
Speaker 3: about a third of the radius, or roughly fifteen percent
Speaker 3: of Mars's total radius is this solid inner core. This
Speaker 3: is a profound revision to our understanding. It shifts our
Speaker 3: model of Mars's interior from that simple, fully liquid core
Speaker 3: picture to a more complex, differentiated one, much more like
Speaker 3: Earth's structure.
Speaker 2: Okay, wow, so we thought it was just liquid and
Speaker 2: now we find this distinct solid part inside. That feels
Speaker 2: like a really big shift. What does this solid inner
Speaker 2: core actually mean for understanding Mars's history and crucially for
Speaker 2: that long loss magnetic field we talked about, Why is
Speaker 2: this particular detail solid inside liquid such a big deal?
Speaker 2: How does it connect to a planet's life support system? Well,
Speaker 2: what's truly profound here is the implication this discovery carries.
Speaker 3: It's huge. The very presence of a solid inner core
Speaker 3: tells us definitively that crystallization is happening. Solidification is taking
Speaker 3: place as the planet cools over geological time. This process
Speaker 3: where liquid metal slowly solidifies at the center and in
Speaker 3: doing so releases latent heat and lighter elements. This process
Speaker 3: is absolutely critical for a planet like Earth to generate
Speaker 3: and sustain its magnetic field for billions of years. It's
Speaker 3: essentially the engine that drives the planetary dynamo.
Speaker 2: Ah. Okay, so the solidifying process itself is the key.
Speaker 3: Yeah, exactly. To elaborate a bit on its magnificance, a
Speaker 3: core structure with both a solid inner part and a
Speaker 3: liquid outer layer is fundamentally much more like Earth's setup
Speaker 3: On Earth, It's precisely the temperature differences and the chemical
Speaker 3: change is happening at that boundary between the solid inner
Speaker 3: core and the swirling liquid outer core, plus the heat
Speaker 3: flowing out into the surrounding mantle that drive the vigorous
Speaker 3: convection currents in that liquid outer layer. As the core
Speaker 3: cools iron crystallizes onto the inner core, this process releases lighter,
Speaker 3: more buoyant elements into the liquid outer core, and these
Speaker 3: lighter fluids than rise, creating convection like a lava lamp effect,
Speaker 3: but with molten metal. These convection currents, this organized movement
Speaker 3: of molten electrically conducting metal, coupled with the planet's spin,
Speaker 3: are the engine from the dynamo that generates a planetary
Speaker 3: magnetic field. Therefore, this new discovery of a solid inner
Speaker 3: core on Mars makes it significantly more likely, much more plausible,
Speaker 3: that a robust dynamo capable of producing a protective magnetic field,
Speaker 3: was indeed active on Mars early in its own and
Speaker 3: perhaps it was sustained for significant period. It provides that
Speaker 3: missing ingredient, that earth like structure needed for a strong,
Speaker 3: long lasting dynamo.
Speaker 2: And for you listening right now, this gives us a
Speaker 2: much clearer, much more scientifically solid pathway for Mars to
Speaker 2: have once had the conditions needed for a thicker atmosphere
Speaker 2: and as a result that abundant flowing liquid water on
Speaker 2: its surface that the geology points to. It connects the
Speaker 2: deep hidden internal processes of the planet directly to the
Speaker 2: surface conditions we were talking about earlier. It closes a
Speaker 2: major loop in our understanding of how Mars could have
Speaker 2: been so different back then.
Speaker 4: Okay, so when we hear about one study like Stalers
Speaker 4: in twenty twenty one initially suggesting a fully liquid core,
Speaker 4: and then another one like Bins just recently reporting a
Speaker 4: solid inner core, it might, you know, at first glance,
Speaker 4: sound like a scientific argument, maybe even a controversy or contradiction.
Speaker 3: That's absolutely not.
Speaker 4: What's happening here is that this is actually a really
Speaker 4: wonderful illustration of how science actually works. It's self correcting
Speaker 4: progressive nature.
Speaker 3: Absolutely not a controversy, noe, not in the sense of
Speaker 3: a fight. It's actually an excellent and incredibly common example
Speaker 3: of the iterative nature of science how data collection and
Speaker 3: analysis evolve. Staler's initial findings in twenty twenty one were,
Speaker 3: without question groundbreaking. A huge first step. They provided the
Speaker 3: first solid constraints on Mars's core size and state, a
Speaker 3: monumental achievement, giving us that first internal glimpse. But as
Speaker 3: they themselves very carefully noted in their paper, the data
Speaker 3: they had available at that specific time and the methods
Speaker 3: they used just didn't have the necessary signal strength or clarity.
Speaker 3: They couldn't definitively confirm or deny the existence of a
Speaker 3: solid inner core. They were very clear about that limitation,
Speaker 3: which is just part of good scientific.
Speaker 2: Practice, right. They pointed out what they couldn't see yet exactly.
Speaker 3: So it's not about one being right and the other wrong.
Speaker 3: Staler's twenty twenty one work was the best possible model
Speaker 3: based on the data and techniques available. Then the new
Speaker 3: study by billion colleagues, well, they benefited from more data,
Speaker 3: newer data accumulated as Insight kept listening recording more marsquakes,
Speaker 3: maybe some deeper or stronger ones. And crucially they applied
Speaker 3: more refined novel data analysis techniques. They basically found clever
Speaker 3: ways to pull out those weaker, more subtle seismic signals
Speaker 3: stignals that were previously either buried in the noise or
Speaker 3: just beyond the detection capability of the earlier methods. It's
Speaker 3: his continuous process. Initial models based on the best evidence
Speaker 3: of the time, get tested, refined, expanded upon as new
Speaker 3: information comes in and as the analytical tools themselves get better.
Speaker 3: This is precisely how scientific understanding deepens. It becomes more
Speaker 3: precise over time, with each new study building carefully on
Speaker 3: the last one.
Speaker 2: It's a fantastic example of the scientific method in action,
Speaker 2: isn't it Not like a Suiden Eureka moment, but this persistent,
Speaker 2: incremental build up of knowledge, and you see this iterative
Speaker 2: process even within related research groups you mentioned. Even Staler's
Speaker 2: initial model was revised slightly in twenty twenty three.
Speaker 3: That's right by Ari Hamuel from University of Pariseta and
Speaker 3: his column. Their updates help to further reconcile insight seismic
Speaker 3: findings with other existing evidence about Mars's core size and density.
Speaker 3: Often these refinements incorporate other types of geophysical data too,
Speaker 3: constraints from Mars's gravity field measurements or its rotation, things
Speaker 3: learned from orbiters. This ongoing dialogue, this constant refinement of
Speaker 3: models and theories as new data comes in. It's absolutely
Speaker 3: central to how science progresses. It's really collaborative, not confrontational,
Speaker 3: a shared journey towards getting a clearer picture.
Speaker 2: Okay, so this isn't the final word, the absolute end
Speaker 2: of the story about Mars's core, but it's a major
Speaker 2: new chapter, a really significant one. What does this new discovery,
Speaker 2: this confirmation of a solid inner core mean for the
Speaker 2: scientific community moving forward? What can we expect next in
Speaker 2: Martian science? Now this piece is in place.
Speaker 3: Oh, this result is absolutely going to have a significant
Speaker 3: and I think very exciting impact within the planetary science community.
Speaker 3: We could definitely expect more reanalyzies of the entire insight
Speaker 3: data set. That's almost guaranteed. Scientists will be scrutinizing these
Speaker 3: new methods used by Bees and colleagues looking for independent confirmation.
Speaker 3: They'll likely apply these techniques to other seismic events, maybe
Speaker 3: look at different types of seismic waves to see if
Speaker 3: they can consistently detect that solid inncore signal and maybe
Speaker 3: refine its properties even further. The goal is always to
Speaker 3: solidify a finding like this through multiple lines of evidence,
Speaker 3: multiple analyzes.
Speaker 2: Makes sense, check the work basically.
Speaker 3: Exactly, check the work, try different approaches, and beyond just
Speaker 3: the seismology, there will be thorough discussion about the broader
Speaker 3: geological and geophysical context. Researchers will be looking in detail
Speaker 3: at how this new model of Mars's interior solid inner
Speaker 3: core liquid outer core fits with everything else we know.
Speaker 3: That includes geochemical models of Mars's bulk composition, the precise
Speaker 3: gravity field data from orbiters that tells us about mass
Speaker 3: distribution inside the planet, and those previous studies of the
Speaker 3: crustal magnetic anomalies. This collaborative, cross disciplinary process is how
Speaker 3: we strengthen our collective understanding of planetary evil. It ensures
Speaker 3: the model makes sense in the big picture. It's honestly
Speaker 3: a very exciting time for Martian seismology and planetary science.
Speaker 3: It's prompting new theoretical models and definitely fueling further investigations
Speaker 3: into the red planet's deep past and maybe even its
Speaker 3: future evolution.
Speaker 2: So let's pull back for the big picture, then, the
Speaker 2: grand narrative of planetary science. Why is understanding the insight
Speaker 2: of Mars this newly revealed internal structure. Why is it
Speaker 2: so critical not just for Mars itself, but for our
Speaker 2: fundamental understanding of planets in general, you know broth here
Speaker 2: in our Solar System and maybe even worlds beyond.
Speaker 3: Yeah, this really raises an important question that goes way
Speaker 3: beyond just Mars. Understanding the interior structure of any planet
Speaker 3: in our Solar System is absolutely critical. It's fundamental if
Speaker 3: we want to develop robust, accurate theories about how these
Speaker 3: celestial bodies form in the first place, how they grow,
Speaker 3: and crucially, how they evolve over billions of years. The
Speaker 3: core really is the engine of planetary change. It influences
Speaker 3: everything from the geology on the surface to whether a
Speaker 3: planet can hold onto its atmosphere. Consider this before insights work,
Speaker 3: and especially before this latest discovery confirming the solid inner core.
Speaker 3: Models for Mars that suggested an internal structure very similar
Speaker 3: to or specifically the differentiated core, with both liquid and
Speaker 3: solid parts capable of powering a long lived dynamo. Well,
Speaker 3: they weren't generally favored. Many models lean towards Mars having
Speaker 3: cooled faster, maybe having a fully liquid core, or perhaps
Speaker 3: one with a different composition that just couldn't support a
Speaker 3: dynamo for as long as Earth's is run.
Speaker 2: So this discovery really changes that baseline assumption. It shifts
Speaker 2: the perspective dramatically. Yes, this confirmation of a solid inner
Speaker 2: core means Mars's early history might have been much more
Speaker 2: earth like deep down than we generally thought possible. And
Speaker 2: this knowledge helps us cackle these really fundamental, profound questions
Speaker 2: like how big does a rocky planet need to be
Speaker 2: to generate and sustain a protective magnetic field over billions
Speaker 2: of years? What are the keing re radients, the compositional factors,
Speaker 2: the thermal conditions required for a planet to maintain the
Speaker 2: habitable climate, an environment where liquid water can persist over
Speaker 2: those vast stretches of geological time. It pushes us to
Speaker 2: rethink the minimum requirements maybe for forming an earth like
Speaker 2: planetary system, and for you listening right now, this knowledge
Speaker 2: it stretches far beyond just our red neighbor, doesn't it.
Speaker 2: It directly feeds into our ongoing very ambitious search for
Speaker 2: habitable exoplanets, those world's orbiting distance stars. As we find
Speaker 2: more and more exoplanets, this detailed case study of Mars
Speaker 2: gives us crucial reference points what to look for. Perhaps
Speaker 2: it helps us better understand the precious rarity of Earth conditions,
Speaker 2: especially that long lived active geodynamo providing our essential shield.
Speaker 2: It really highlights what a truly unique, and you could
Speaker 2: say fortunate world, our home planet is still protected by
Speaker 2: its powerful internal engine humming along after four and a
Speaker 2: half billion years. So we're left with a much richer picture, now,
Speaker 2: a far more dramatic and ultimately a more nuanced story
Speaker 2: of Mars. It wasn't always it is just the cold,
Speaker 2: barren desert we see today, completely lacking that global magnetic protection.
Speaker 2: It seems it had a fighting chance, didn't it, an
Speaker 2: internal engine that was once very much alive.
Speaker 3: In kicking Precisely, we now have much stronger, more direct
Speaker 3: seismic evidence supporting it. Past Mars, that was a truly
Speaker 3: dynamic world, a world with an earth like core generating
Speaker 3: a powerful magnetic field, which in turn likely sustained a
Speaker 3: thicker atmosphere and allowed for very probably abundant flowing liquid
Speaker 3: water on its surface. Its transformation into the cold, dry
Speaker 3: desert planet we know today wasn't instantaneous, but it was
Speaker 3: this gradual yet profound planetary drama, a saga driven directly
Speaker 3: from its very core outwards as that internal engine eventually
Speaker 3: cool slowed down, and the dynamo dyet. It serves as
Speaker 3: this really powerful illustration how the internal processes of a planet,
Speaker 3: those hidden mechanics deep beneath the surface, ultimately dictate the
Speaker 3: surface environment and by extension, is potential for supporting life. Mars,
Speaker 3: in many ways, is a cautionary dale. It's a natural
Speaker 3: laboratory showing us what can happen when a planet loses
Speaker 3: the vital internal protections hashtash tag tag outrop.
Speaker 2: Wow, what an incredible journey we've taken today, Venturing from
Speaker 2: the dusty, familiar surface of Mars right down to its
Speaker 2: newly revealed core, a solid inner core, surprisingly earthlake. We've
Speaker 2: seen how this patiently gathered seismic data collected over years
Speaker 2: by insight, combined with ingenious refined analysis, can unravel mysteries
Speaker 2: millions and millions of miles away. It's just a testament,
Speaker 2: isn't it, to the power of scientific exploration and that
Speaker 2: relentless human drive to understand our universe, one planet, one
Speaker 2: core at a time. It's almost poetic really that after
Speaker 2: all these years of just gazing at Mars, sending rovers
Speaker 2: to taste soil, or finally getting to listen to its heartbeat.
Speaker 3: Yeah, this ongoing exploration of Mars interior, it really reminds
Speaker 3: us that the planets in our Solar System aren't just
Speaker 3: static objects hanging in space. They are dynamic worlds. They
Speaker 3: have complex, often dramatic histories. They're constantly evolving, constantly transforming
Speaker 3: over cosmic time scales. The Insight mission, even though it's
Speaker 3: now silent on the marsh and planes, it continues to
Speaker 3: speak volumes through its invaluable data. It's pushing us ever
Speaker 3: closer to understanding the dramatic saga of the red planet
Speaker 3: and really, by extension, our own place within the cosmos.
Speaker 3: It truly reshapes our understanding of how planets like ours evolve.
Speaker 2: So as we wrap up this exploration, maybe consider this
Speaker 2: Mars story. It's journey from a potentially vibrant, watery world
Speaker 2: shielded by a magnetic field, much like Earliers, perhaps to
Speaker 2: the dry, barren desert it is today. It's a stark reminder,
Speaker 2: isn't it, of how fragile planetary habitability it can actually be.
Speaker 2: It's this delicate balance of internal processes external forces, a
Speaker 2: kind of cosmic dance that can turn a world from
Speaker 2: blue and wet to red and dry over billions of years.
Speaker 3: And maybe ask yourself, what if lurking deep within other
Speaker 3: seemingly barren worlds we observe out there there are similar clues,
Speaker 3: clues to pass lives, past habitability, or maybe even the
Speaker 3: subtle potential for future transformations we haven't considered. Mars really
Speaker 3: asks us how truly unique is Earth state? And what
Speaker 3: other profound place planetary secrets are just waiting to be revealed,
Speaker 3: hidden beneath the surfaces of other worlds, just waiting for
Speaker 3: us to listen patiently to their whispers across the silence
Speaker 3: of space.
Speaker 2: Yousssssss