Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomy 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: When you picture an asteroid, I can almost guarantee what's
Speaker 2: playing in your head right now. It's that iconic, totally
Speaker 2: chaotic chase scene from the Empire Strikes Back.
Speaker 3: Oh yeah, the Millennium Falcon, just darting through that densely
Speaker 3: packed field of tumbling space rock.
Speaker 2: Exactly just bouncing off each other, creating this impossible three
Speaker 2: dimensional maze. And I mean it's a thrilling visual for
Speaker 2: you as a viewer, but it is a complete.
Speaker 3: Just massive violation of arble mechanics. It's really a masterclass
Speaker 3: in terrible.
Speaker 2: Astrophysics, right because the reality of the main asteroid belt
Speaker 2: is well, it's profoundly lonelier than that.
Speaker 3: Vastly lonelier. The objects out there are separated by these
Speaker 3: just incomprehensible distances. I mean, if you were actually standing
Speaker 3: on an asteroid in the main belt, you would likely
Speaker 3: need a telescope just to see the next closest one.
Speaker 1: Wow.
Speaker 3: Yeah, it's a vast, mostly empty expanse. It is definitely
Speaker 3: not a cosmic pinball machine.
Speaker 2: And I think that emptiness sets us up for an
Speaker 2: even bigger misconception, you know, because we just assume that
Speaker 2: every single one of these sparsely distributed objects is well
Speaker 2: just a dusty.
Speaker 3: Gray rock, right, the standard floating rock assumption.
Speaker 2: Yeah, but today we're totally dismantling that Hollywood myth because
Speaker 2: out there in the dark, there is an object that
Speaker 2: completely defies that assumption. It isn't rock at all. We're
Speaker 2: talking about asteroid sixteen Psyche.
Speaker 3: Psyche is amazing.
Speaker 2: It's roughly the size of Massachusetts, right.
Speaker 3: Roughly, Yeah, the Massachusetts size, kind of lumpy potato shaped
Speaker 3: body that is comprised almost entirely of metal.
Speaker 2: Which is just wild to think about, just a giant
Speaker 2: metal potato.
Speaker 3: And space iron and nickel to be specific. And the
Speaker 3: working hypothesis in the planetary science community right now is
Speaker 3: that sixteenth Hyche isn't just some random clump of heavy
Speaker 3: metals that happened to stick together, Right, it's actually the
Speaker 3: exposed frozen core of a lost protoplanet, a world was
Speaker 3: violently stopped from forming during the very earliest days of
Speaker 3: the Solar System.
Speaker 2: So we are looking at a dead planet's heart basically.
Speaker 3: Essentially, Yes, And by looking at this massive impact basin
Speaker 3: on Psyche's north pole and running these incredibly complex computational
Speaker 3: simulations of how that specific crater formed, we can start
Speaker 3: to sort of reverse engineer the exact mechanics of the
Speaker 3: demolition derby that gave rise to the planets we have today.
Speaker 2: Okay, let's untack this, because if we think of the
Speaker 2: early Solar System as this chaotic construction site I'm trying
Speaker 2: to picture, is Psyche essentially leftover rebar?
Speaker 3: I like that leftover rebar is actually a highly accurate
Speaker 3: way to conceptualize the kinematics of the early Solar System.
Speaker 2: Because, I mean, we know that in a fully formed planet,
Speaker 2: the dense metals sink to the center to form a core, right,
Speaker 2: and then the lighter silicates float up to form the
Speaker 2: mantle in the crust.
Speaker 3: Exactly, that's differentiation.
Speaker 2: So for a planet's core to end up just floating
Speaker 2: completely naked in the vacuum of space. It had to
Speaker 2: have been entirely stripped of all those outer rocky layer.
Speaker 3: Yeah, totally stripped, because back then we didn't have these
Speaker 3: neat orderly planetary orbits the ease. Today we had a
Speaker 3: swirling accretion.
Speaker 2: Disk, just a mess of material.
Speaker 3: A total mess. Gravity pulled gas and dust into small
Speaker 3: clumps which collided to form planet tesimals. And as these
Speaker 3: planet casimals accreted mass, the kinetic energy of constant impacts
Speaker 3: combined with the decay of short lived radioactive isotopes like
Speaker 3: aluminum twenty six, it generated immense paternal heat.
Speaker 2: Right, and that heat is what triggers the differentiation you
Speaker 2: mentioned exactly.
Speaker 3: You get this global magma ocean phase. The iron and
Speaker 3: nickel physically separate from the silicates and sink down into
Speaker 3: the gravity well of the body.
Speaker 2: They just dropped to the center.
Speaker 3: Yes, the silicate metal partitioning. And the thing is Psyche
Speaker 3: was on that exact trajectory. It had differentiated. It had
Speaker 3: an iron core and a thick rocky mantle and a crust.
Speaker 2: It was on its way to being a real planet.
Speaker 3: It was, but the environment was defined by just catastrophic violence.
Speaker 3: The prevailing model suggests Psyche was subjected to a series
Speaker 3: of what we call hid and run collisions.
Speaker 2: Hit and run, like they didn't just smash together and merge.
Speaker 3: Not always, No, we're talking about other massive planetesimals, you know,
Speaker 3: perhaps hundreds of kilometers across, slamming into it at velocities
Speaker 3: of five to twenty kilometers per second.
Speaker 2: Oh my god, five to twenty kilometers a second.
Speaker 3: Yeah, And at those velocities, the kinetic energy transferred during
Speaker 3: the impact is well, it's staggering. It wouldn't just leave
Speaker 3: a crater, it would actually overcome the gravitational binding energy
Speaker 3: of the mantle itself.
Speaker 2: So it's hitting it so hard that the rock just
Speaker 2: it can't hold on anymore.
Speaker 3: The sheer physics of it are brutal. The shock waves
Speaker 3: from a collision of that magnitude, they travel through the body,
Speaker 3: compressing the material, and then they reflect back as rare
Speaker 3: faction waves.
Speaker 2: Where are faction waves?
Speaker 3: Yeah, tensile waves that literally tear the rock apart from
Speaker 3: the inside out. And if the impact angles oblique enough,
Speaker 3: like a grazing blow rather than a dead on center mass.
Speaker 2: Strike, it just takes the top right off exactly.
Speaker 3: The kinetic energy shears the outer rocky layers completely off
Speaker 3: the protoplanet, it accelerates that silicate debris well beyond escape velocity.
Speaker 2: Wow, so the rock just flies off into space forever.
Speaker 3: Right, But it leaves the much denser, highly cohesive iron
Speaker 3: core intact. And if you do this a few times,
Speaker 3: just strip away layer after layer, the crust and mantle
Speaker 3: are gone. You're left with this unyielding metallic core totally
Speaker 3: stripped of its protective layers.
Speaker 2: So looking at Psyche out there and the main belt
Speaker 2: is really like looking at a ghost. It's the skeletal
Speaker 2: remains of a world that could have been a neighbored
Speaker 2: Earth or Mars or Venus world.
Speaker 3: Yeah, but from a purely scientific standpoint, this planetary casualty
Speaker 3: is just a massive, massive opportunity.
Speaker 2: For us because it solves that fundamental limitation we have
Speaker 2: when we try to study the deep interior of our
Speaker 2: own planet.
Speaker 3: Yes, it's the ultimate irony of our discipline, honestly. I mean,
Speaker 3: we have rovers analyzing the isotopic composition of.
Speaker 2: Martian regolith right millions of miles away.
Speaker 3: Millions of miles away, but we are embarrassingly ignorant about
Speaker 3: the deep interior of the very sphere we are standing on.
Speaker 2: I mean, if you're wondering why we don't just drill
Speaker 2: down to find out what's the center of the earth,
Speaker 2: the math is incredibly.
Speaker 3: Humbling, extremely humbling. The distance from the surface to the
Speaker 3: center of the Earth is roughly six three hundred kilometers.
Speaker 2: Which is almost four thousand miles straight down.
Speaker 3: Straight down. Now compare that to the deepest artificial whole
Speaker 3: humanity has ever created, the Cola super deep borehole in Russia.
Speaker 2: Right, how deep did they get?
Speaker 3: They reached twelve point two six kilometers before the project
Speaker 3: had to be abandoned.
Speaker 2: Twelve point two six kilometers, So out of sixy three
Speaker 2: hundred we've gone.
Speaker 3: Twelve yep, which is roughly zer point two percent of
Speaker 3: the way down.
Speaker 2: I always think of the apple analogy. We live on
Speaker 2: the absolute thinnest part of the skin of the apple,
Speaker 2: and we've barely even managed to scratch that skin, let
Speaker 2: alone get anywhere near the seeds in the center.
Speaker 3: It's a perfect analogy. We haven't even pierced the crust entirely,
Speaker 3: let alone reached the mantle of the core. And the
Speaker 3: limitation isn't just a lack of engineering willpower. It's the
Speaker 3: geothermal gradient and the extreme pressure.
Speaker 2: Because it just gets hotter and heavier the deeper you go.
Speaker 3: Right, It's a matter of fundamental thermodynamics and material science.
Speaker 3: As you descend, the pressure increases to millions of atmospheres,
Speaker 3: and the temperature at the core mantle boundary, it's hot
Speaker 3: enough to melt literally any drill bit we could conceivably manufacture.
Speaker 2: It just turns to liquid instantly yea.
Speaker 3: And the rock down there it ceases to behave like
Speaker 3: a brittle solid. Altogether, it acts like a highly viscous,
Speaker 3: flowing plastic. We are functionally permanently locked out.
Speaker 2: So if we can't physically go down there, how do
Speaker 2: we know what's in our core at all?
Speaker 3: We have to rely on indirect measurements, specifically seismic tomography.
Speaker 3: We watch how pways and s ways from earthquakes propagate
Speaker 3: and how they refract and reflect through the Earth's internal
Speaker 3: layers like.
Speaker 2: An ultrasound for the planet.
Speaker 3: Exactly like an ultrasound. Yeah, but seismic data is essentially
Speaker 3: a blurry sonogram. We can see density changes like the
Speaker 3: Leman discontinuity.
Speaker 2: Which is the boundary that separates the liquid outer core
Speaker 2: from the solid inner core.
Speaker 3: Right spot on. We can see that boundary exists, but
Speaker 3: we can't sample the material. We can't put it in
Speaker 3: a mass spectrometer. We are just guessing based on how
Speaker 3: sound waves bend, which.
Speaker 2: Makes sixteen Psyche the ultimate proxy. I mean, if we
Speaker 2: can't go down into our own planet to see a core,
Speaker 2: we have to look up because the universe has conveniently
Speaker 2: cracked a planet open and left its core just sitting
Speaker 2: in the freezer space for us to look at.
Speaker 3: Yes, it's the only place in the entire Solar System
Speaker 3: where we can directly observe the engine room of a planet.
Speaker 3: And that is exactly why NASA launched the Psyche spacecraft
Speaker 3: in late twenty twenty.
Speaker 2: Three, just a mission dedicated entirely to flying alongside this
Speaker 2: asteroid to take direct measurements right.
Speaker 3: To finally get some ground truth data on what a
Speaker 3: planetary core actually looks like up close.
Speaker 2: But the wait time on orbital mechanics is just brutal.
Speaker 2: I mean, the probe won't arrive until August of twenty
Speaker 2: twenty nine.
Speaker 3: It takes a long time to get out there.
Speaker 2: So in the meantime, with the spacecraft still years away,
Speaker 2: planetary scientists aren't just twiddling their thumbs waiting for photos
Speaker 2: to download.
Speaker 3: Oh, definitely not. We already have some ground based telescope data,
Speaker 3: radar imaging, and light curve inversion.
Speaker 2: Models, and that gives us a fuzzy, low resolution shape
Speaker 2: model of the asteroid.
Speaker 3: Very fuzzy, but we can see it's that lumpy potato shape,
Speaker 3: and we can make out a massive impact basin near
Speaker 3: its north polar region.
Speaker 2: But trying to figure out the internal structure based on
Speaker 2: a blurry silhouette millions of miles away, that requires some
Speaker 2: intense computational forensics, right.
Speaker 3: Exactly, And this is where they reach and break through
Speaker 3: research led by Namia by All at the University of
Speaker 3: Arizona really comes into play. If we can't physically sample
Speaker 3: the asteroid yet, we have to use advanced hydrocodes to
Speaker 3: simulate the specific impact that created that North Pole crater.
Speaker 2: Okay, wait, what exactly is a hydrocode.
Speaker 3: Hydrocode is a highly specialized computational tool. It's used to
Speaker 3: model the behavior of continuous media under extreme conditions.
Speaker 2: Like a hypervelocity asteroid impact.
Speaker 3: Right, Because things don't behave normally when they hit each
Speaker 3: other at ten kilometers a second, solid rock and metals
Speaker 3: start acting almost like fluids, and you can't just model
Speaker 3: a generic sphere colliding with a flat surface. The geometry
Speaker 3: of the target dictates how the shockwave propagates.
Speaker 2: Because hitting a curved ridge line on a potato shaped
Speaker 2: asteroid is going to yield a completely different crater geometry
Speaker 2: than hitting a flat plane.
Speaker 3: Precisely so, Byell's team had to painstakingly program in Psyche's lumpy,
Speaker 3: irregular shape into the simulation.
Speaker 2: Wow, And they also had to test different internal structures, right,
Speaker 2: since we don't know the exact composition beneath the surface.
Speaker 3: Yes, they ran simulations with two very different internal models.
Speaker 3: First a homogeneous model, which assumes Psyche is just a solid,
Speaker 3: uniform block of iron nickel alloy all the way from
Speaker 3: the surface to the center.
Speaker 2: Like a giant cannon ball.
Speaker 4: Right.
Speaker 3: And then they also ran a layered model, testing the
Speaker 3: hypothesis that maybe the core still retains a thin outer
Speaker 3: shell of different material.
Speaker 2: Like maybe some heavily shocked silicates or volcanic rock that
Speaker 2: somehow survived those ancient hit and run collisions.
Speaker 3: Exactly when they run these simulations, literally firing virtual projectiles
Speaker 3: at virtual metal potatoes in a supercomputer. They are analyzing
Speaker 3: the resulting creter morphology, and specifically, they are looking at
Speaker 3: a metric known as the depth diameter ratio.
Speaker 2: The depth diameter ratio eye. So, just to visualize this,
Speaker 2: if I drop a heavy steel ball bearing into a
Speaker 2: bowl of loose flour, the flower yields really easily, right,
Speaker 2: and I get a deep, relatively narrow crater. Yes, But
Speaker 2: if I drop that same ball bearing into a dense
Speaker 2: block of wet clay, the clay resists the kinetic energy differently,
Speaker 2: resulting in a wider or much shallower crater.
Speaker 3: That's a great way to think about it. The physical
Speaker 3: properties of the target material, its density, it's yield strength,
Speaker 3: it's equation of state. Those dictate the final geometry of
Speaker 3: the crater, how deep it is compared to how wide
Speaker 3: it is.
Speaker 2: It's like a cosmic fingerprint.
Speaker 3: It really is. By altering the internal structure in the
Speaker 3: hydrocode and measuring the resulting depth diameter ratio of the
Speaker 3: virtual crater, Bisel's team is reverse engineering a multi billion
Speaker 3: year old impact. They are hunting for the simulated interior
Speaker 3: that produces a crater that perfectly matches the dim blurry
Speaker 3: depression we can currently observe from Earth.
Speaker 2: That is so clever. But in running these models, here's
Speaker 2: where it gets really interesting. They isolated a hidden variable
Speaker 2: that completely upends how we assume a solid metal asteroid
Speaker 2: should behave.
Speaker 3: Yes, porosity.
Speaker 2: They found that porosity is actually the driving factor in
Speaker 2: crater formation on Psyche.
Speaker 3: Macro porosity specif the amount of empty space, deep voids
Speaker 3: and internal fracturing inside the asteroid.
Speaker 2: But wait, if Psyche is a metallic core that formed
Speaker 2: under immense pressure at the center of a proto planet,
Speaker 2: its initial state would be incredibly dense, right, like virtually
Speaker 2: zero porosity.
Speaker 3: It would have been pristine.
Speaker 2: Yes, So why would a giant chunk of iron and
Speaker 2: nickel floating in space be porous? I mean, a solid
Speaker 2: block of steel doesn't avoids in it, It's solid.
Speaker 3: The initial core was undoubtedly dense, But you have to
Speaker 3: remember the apocalyptic violence of Psyche's history. When you slam
Speaker 3: massive planet tesimols into it at ten kilometers per second,
Speaker 3: the kinetic energy doesn't just vaporize the crust and.
Speaker 2: Stop there, right, The energy has to go somewhere.
Speaker 3: The shockwaves travel deep into the metallic core. Now, the
Speaker 3: metal is incredibly strong, obviously, but it isn't invincible. These
Speaker 3: impacts can actually exceed what's called the hugoniot elastic limit
Speaker 3: of the iron alloy.
Speaker 2: The hugonia elastic limit, meaning it hits it so hard
Speaker 2: it permanently deforms or breaks the metal.
Speaker 3: Brutally fractures it. It creates massive internal fault lines. The
Speaker 3: metal is shattered into a tightly packed rubble pile, essentially
Speaker 3: held together only by its own weak gravity.
Speaker 2: Okay, so it's less like a pristine bowling ball of
Speaker 2: steel and more like, I don't know, a heavily fractured
Speaker 2: medieval shield that's just taken way too many hits.
Speaker 3: That's yeah, exactly. It holds its macro shape. It looks
Speaker 3: solid from the outside, but internally there are vast networks
Speaker 3: of cracks and gaps. It's a metallic sponge.
Speaker 2: A metallic sponge. Wow. And that internal empty space completely
Speaker 2: changes how the material absorbs the kinetic energy of a
Speaker 2: new impact.
Speaker 3: It changes the energy partitioning entirely, because think about it,
Speaker 3: If you strike a solid block of dense steel, the
Speaker 3: energy of the blow is transmitted almost perfectly through the
Speaker 3: material as an elastic wave. It just rings through it, right,
Speaker 3: and much of that energy goes into excavating the crater
Speaker 3: throwing material outwork.
Speaker 2: Okay, But if the target is highly porous, like our
Speaker 2: metallic sponge, then.
Speaker 3: The energy does what we call pdvwork pressure volume work.
Speaker 3: The shockwave energy is literally consumed by physically crushing the
Speaker 3: voids and compressing the material inward on itself.
Speaker 2: So the empty space collapses.
Speaker 3: It collapses, and that.
Speaker 2: Compression that generates intense localized heat.
Speaker 3: Massive heat. So instead of just blasting material away and
Speaker 3: excavating a deep hole, a highly porous Psyche would crush inward,
Speaker 3: absorbing the blow locally, which fundamentally alters that depth diamber
Speaker 3: ratio of the crater. We see.
Speaker 2: It's like hitting a crumple zone in a car, exactly.
Speaker 3: Like a crumple zone. And this leads to a fascinating
Speaker 3: paradox regarding the fate of the impactor itself. You know,
Speaker 3: the alien rock that actually crashed into Psyche's north pole
Speaker 3: to make the crater.
Speaker 2: Right, what happens to the bullet?
Speaker 3: Well, the hydrocode simulations revealed something totally counterintuitive. A stronger,
Speaker 3: more solid, low porosity interior actually preserves large amounts of
Speaker 3: the impactor really, yes, while a weaker, highly porous interior
Speaker 3: results in the impact or vaporizing or shattering into microscopic fragments.
Speaker 2: But if the target is highly porous and crushes inward,
Speaker 2: wouldn't that like trap the heat of the impact. It
Speaker 2: sounds like the impactor would just be cooked inside the
Speaker 2: crater rather than bouncing off.
Speaker 3: That is exactly the thermodynamic mechanism at play. The crushing
Speaker 3: action acts as an energy trap. The extreme heat and
Speaker 3: pressure are localized right at the point of contact, enveloping
Speaker 3: the impactor in the zone of extreme violence, so.
Speaker 2: It just melts.
Speaker 3: The temperature spikes so rapidly that the impact is subjected
Speaker 3: to shock melting or outright vaporization. But if the target
Speaker 3: is solid, dense metal, it cannot easily crush inward.
Speaker 2: Right there are no voids to collapse, so the energy
Speaker 2: propagates outward in a massive shock wave, violently excavating the crater.
Speaker 3: The impactor is heavily fragmented, sure, but larger chunks of
Speaker 3: it can actually survive the initial contact and become embedded
Speaker 3: in the solid metal floor of the crater because that
Speaker 3: localized thermal trap never formed.
Speaker 4: Wow.
Speaker 2: So when the Psyche spacecraft finally arrives in twenty twenty nine.
Speaker 2: Its instrument payload is going to be hunting for those
Speaker 2: exact fragments.
Speaker 3: Yes, the probe is carrying a gamma ray and neutron spectrometer,
Speaker 3: the GRNs.
Speaker 2: Right, And the GRNs is a vital piece of this
Speaker 2: puzzle because it detects the energy signatures of cosmic rays
Speaker 2: interacting with the asteroid surface.
Speaker 3: Correct Different elements emit different spectraa of gamma rays and
Speaker 3: neutrons when struck by cosmic rays.
Speaker 2: So by mapping those elemental signatures, the probe will be
Speaker 2: able to see if there are high concentrations of exogenous
Speaker 2: silicates basically alien rock, sitting in the bottom of that
Speaker 2: North Pole crater exactly.
Speaker 3: And if the spectrometer detects large chunks of rocky material
Speaker 3: embedded in the metal, it tells.
Speaker 2: Us that Psyche's interior is dense and solid.
Speaker 3: Yes, But if it finds very little rocky material, it
Speaker 3: tells us Psyche is a heavily fractured porous sponge that
Speaker 3: vaporized its attacker.
Speaker 2: It's literally planetary forensics via orbital spectrometry.
Speaker 3: It's beautiful science, and the hypotheses generated by Bazal's three
Speaker 3: D models are essential here because they calibrate the instruments
Speaker 3: on the spacecraft. We aren't flying blind and we get
Speaker 3: there in twenty twenty nine. The hydrocods tell us exactly
Speaker 3: what elemental signatures and creater morphology is to look for
Speaker 3: to answer these questions.
Speaker 2: I mean, just studying the microscopic thermal dynamics of a
Speaker 2: crater on a dead metal potato is an incredible display
Speaker 2: of physics on its own, it really is. But you know,
Speaker 2: as we zoom out, the implications of understanding psyche stretch far,
Speaker 2: far beyond just the main asteroid belt.
Speaker 3: Oh definitely.
Speaker 2: So what does this all mean for us? Because this
Speaker 2: data actually scales up to one of the most significant
Speaker 2: questions in modern astrophysics, right, the search for habitable exoplanets.
Speaker 3: It does, and to understand that connection we have to
Speaker 3: look at planetary geodynamos.
Speaker 2: Geodynamos the engines inside a planet.
Speaker 3: Right, Planetary cores are not static lumps of metal deep
Speaker 3: inside the Earth. The iron core is partitioned into a
Speaker 3: solid inner core and a liquid outer core.
Speaker 2: And the immense heat radiating from that inner core, combined
Speaker 2: with the Coriolis force from the Earth spinning creates these
Speaker 2: massive twisting convection currents in the liquid metal.
Speaker 3: Yes, magneto hydrodynamics, because the liquid metal is a conductor,
Speaker 3: that turbulent churning motion generates a massive electromagnetic field that
Speaker 3: extends far out into space around our planet.
Speaker 2: And that magnetic field is the absolute prerequisite for habitability
Speaker 2: on the surface, isn't it.
Speaker 3: It is the shield Space is an intensely irradiated environment.
Speaker 3: Stellar winds these streams of highly energetic charged particles flowing
Speaker 3: from a star. They will relentlessly strip away a planet's
Speaker 3: atmosphere if it isn't deflected.
Speaker 2: And without an atmosphere, you can't have liquid water, you
Speaker 2: can't have life exactly.
Speaker 3: We see that exact scenario in our own solar system.
Speaker 3: Mars lost as planetary dynamo.
Speaker 2: Its core just cooled down.
Speaker 3: The core cooled, the convection stopped, and the magnetic shield
Speaker 3: completely collapsed. And once that shield was gone, the solar
Speaker 3: wind just eroded the Martian atmosphere over billions of years,
Speaker 3: turning it into the irradiated desert we see today.
Speaker 2: That is terrifying. So if we want to find an
Speaker 2: exoplanet capable of supporting complex life, particularly in the habitable
Speaker 2: zones of highly active en dwarf stars, which are notorious
Speaker 2: for violent stellar flares.
Speaker 3: We need to find planets with the right internal engines.
Speaker 3: They must possess a metallic core capable of generating and
Speaker 3: sustaining a strong geodynamo over billions of years.
Speaker 2: But right now, our theoretical models for how these metallic
Speaker 2: cores form, how their thermal evolution works, and how they
Speaker 2: partition light elements like sulfur or oxygen into the iron alloy.
Speaker 3: Are calibrated entirely on that point two percent of indirect
Speaker 3: data we have from.
Speaker 2: Earth, which is basically nothing.
Speaker 3: We're guessing we are extrapolating massively from very limited data,
Speaker 3: But Psyche provides the missing ground truth data. By directly
Speaker 3: studying an exposed core, measuring its porosity, mapping its elemental composition,
Speaker 3: and looking for remnant magnetic fields that might literally be
Speaker 3: frozen into its crust.
Speaker 2: We can physically verify our equations of state for core
Speaker 2: materials exactly.
Speaker 3: The data returned in twenty twenty nine will be fed
Speaker 3: directly into the computational models that astronomers use to analyze
Speaker 3: exoplanetary masses and densities.
Speaker 2: So if we spot a super Earth fifty light years.
Speaker 3: Away, the findings from Psyche will dictate our confidence in
Speaker 3: whether that distant world has the internal thermal dynamics required
Speaker 3: to generate a magnetic shield. We are literally analyzing the
Speaker 3: anatomy of a dead world to refine our search parameters
Speaker 3: for living ones.
Speaker 2: Which fundamentally changes how we view this asteroid. I mean,
Speaker 2: we've gone from dismissing it as just another piece of
Speaker 2: space debris in an empty belt to recognizing it as
Speaker 2: a critical calibration tool for the entire field of planetary science.
Speaker 2: It is a keystone object, from the complex hydrocode simulations
Speaker 2: of hypervelocity impacts to the totally counterintuitive thermodynamics of metallic porosity,
Speaker 2: to the macro level search for habitable exoplanets. Psyche is
Speaker 2: the physical bridge connecting the chaotic birth of our Solar
Speaker 2: system to our understanding of the broader galaxy.
Speaker 3: It is a remarkable convergence of disciplines. But I want
Speaker 3: to leave you with a consideration that highlights it's the
Speaker 3: inherent risk and the thrill of this type of exploration.
Speaker 3: Throughout all of our modeling, the hydrocodes, the assumptions about
Speaker 3: depth's diameter ratios. We are operating on a fundamental bias.
Speaker 2: A bias how so, we.
Speaker 3: Are assuming that Psyche's composition somewhat mirrors what we expect
Speaker 3: to find deep within the Earth. We assume it is
Speaker 3: primarily an ironickel alloy behaving according to the phase diagrams
Speaker 3: we have constructed in our terrestrial laboratories.
Speaker 2: Oh, I see, we're assuming Earth rules.
Speaker 3: Apply out there exactly. But what if we are projecting
Speaker 3: our Earthly expectations onto an alien body? What if the
Speaker 3: spacecraft arrives in August twenty twenty nine, powers up its
Speaker 3: spectrometers and discovers that this naked core is composed of
Speaker 3: exotic alloys, strange isotopic ratios, or materials that behave under
Speaker 3: shock pressures in ways that are entirely unaccounted for in
Speaker 3: our current physics. Wow, what if the building blocks of
Speaker 3: the early Solar System were far stranger than the planets
Speaker 3: we ended up with.
Speaker 2: That is the ultimate promise of deep space exploration. Isn't
Speaker 2: it the possibilit that the universe is about to hand
Speaker 2: us data that shatters our existing models, forcing us to
Speaker 2: just rewrite the textbooks on planetary formation from scratch.
Speaker 3: It happens more often than you think.
Speaker 2: The wait until twenty twenty nine is going to be
Speaker 2: absolutely agonizing, but the potential payoff is a fundamental shift
Speaker 2: in how we understand the ground beneath our feet and
Speaker 2: the exoplanets across the galaxy. Thank you for exploring the
Speaker 2: mechanics of this lost world with us. The next time
Speaker 2: you look out at the night sky, look past the
Speaker 2: empty space and picture the invisible, frozen histories and the
Speaker 2: poorest metallic hearts silently carrying the secrets to our past
Speaker 2: in our future. Until next time, keep looking.
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