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: Hello, and welcome back to our exploration of the fascinating
Speaker 2: world of science and discovery. It is Tuesday, February seventeenth,
Speaker 2: twenty twenty six, and today we are we're pointing our
Speaker 2: attention upward, way up.
Speaker 3: We are. Indeed, we're looking at our nearest neighbor, the
Speaker 3: celestial body that has captivated humanity since we first looked
Speaker 3: up at the night sky.
Speaker 2: The Moon. It's the ultimate constant, right You look up
Speaker 2: at night, and there it is. Sometimes it's a sliver,
Speaker 2: sometimes it's a big, bright orb, but it's always there.
Speaker 2: It's comforting, it's reliable, and I think if you ask
Speaker 2: the app rich person on the street, or even me
Speaker 2: honestly before reading this material, to describe the Moon's geology,
Speaker 2: they probably say it's a done.
Speaker 3: Deal, a fossil that's the word that's often used in textbooks.
Speaker 2: A planetary fossil exactly, a big, silent, gray rock where
Speaker 2: nothing has really happened since the dinosaurs were wiped out,
Speaker 2: maybe even longer. You see the craters, the dark spots,
Speaker 2: and you figure, okay, that's the furniture. It hasn't been
Speaker 2: rearranged in billions of years.
Speaker 3: It feels static unchanging.
Speaker 2: It does. But the source material we are unpacking today
Speaker 2: is going to dismantle that idea pretty thoroughly. It turns
Speaker 2: out that dead is a very relative term in planetary science.
Speaker 3: It absolutely is, and this new study really drives that
Speaker 3: point home. We're learning that our quiet neighbor is well,
Speaker 3: not so quiet.
Speaker 2: Not at all. We have a fascinating new study here
Speaker 2: published in the Planetary Science Journal, coming from a team
Speaker 2: at the National Air and Space Museum Center for Earth
Speaker 2: and Planetary Studies, and the headline is not just that
Speaker 2: the moon is active, is that the Moon is actively
Speaker 2: shrinking and shaking. Don't forget the shaking, right, It's getting
Speaker 2: smaller and it's trembling while it's doing it. So our
Speaker 2: mission for this discussion is to unpack this incredible global
Speaker 2: map and analysis produced by these scientists. We're going to
Speaker 2: talk about a specific geological feature called small mare ridges
Speaker 2: or SMRs for sure SMRs ye, And we're going to
Speaker 2: figure out why the Moon is wrinkling up like a raisin,
Speaker 2: and more importantly, what that actually means for the humans
Speaker 2: we are planning.
Speaker 3: To send back there, because it really changes the risk profile.
Speaker 3: It changes it significantly for future explorers.
Speaker 2: So let's start with the discovery itself. The study centers
Speaker 2: on these small mirror ridges. I love a good acronym,
Speaker 2: so we're calling them SMRs. But before we get into
Speaker 2: the numbers, help me visualize this. If I'm an astronaut
Speaker 2: standing on the Moon looking at an SMR, what am
Speaker 2: I actually seeing?
Speaker 3: Okay? So to visualize this, you have to understand the landscape. First,
Speaker 3: the Moon basically has two types of terrain. Very broadly speaking,
Speaker 3: you have the highlands, the bright parts. The bright parts exact,
Speaker 3: they're rugged, heavily cratered, mountainous areas. Think of the man
Speaker 3: in the moon's face. The light parts. This is the
Speaker 3: ancient original crust of the moon.
Speaker 2: Okay, the rugged white parts, got it.
Speaker 3: And then you have the Maria, the seas from the
Speaker 3: Latin Maria is Latin four seas. Yes, these are the dark,
Speaker 3: flat plains that make up the other features of the
Speaker 3: Man in the Moon. Ancient astronomers looking through early telescopes
Speaker 3: thought they were actual bodies of water because they look
Speaker 3: so smooth compared to the mountains.
Speaker 2: But they're not water, no, not at all.
Speaker 3: We know now. They are vast solidified lava flows, mostly basalt,
Speaker 3: very dark rock.
Speaker 2: Okay, so I'm standing in the middle of a basalt plain.
Speaker 2: It's dark, it's flat, it's covered in that fine dust.
Speaker 2: It's supposed to be the flattest, smoothest part of the Moon, right,
Speaker 2: the easy place to land.
Speaker 3: That's been the assumption. Yes, for a long time, we
Speaker 3: thought it was relatively featureless, you know, barring the occasional
Speaker 3: impact crater. But this study, led by col Nikofhr and
Speaker 3: Tom Waters, has produced the first globe map of these SMRs.
Speaker 2: And what would it look like.
Speaker 3: If you were standing there. You wouldn't see a giant
Speaker 3: mountain range like the Rockies. You'd see a ridge wrinkle
Speaker 3: in the ground.
Speaker 2: How big are we talking? Is it like a speed
Speaker 2: bumph or more like a hill.
Speaker 3: Bigger than a speed bump. They are small in planetary terms,
Speaker 3: that's why they have that name. But they would be
Speaker 3: pretty substantial if you're trying to hike over one. We're
Speaker 3: talking about scarps, which are cliffs or steep slopes that
Speaker 3: might rise tens of meters high tens.
Speaker 2: Of meters, so like a multi story building exactly.
Speaker 3: And they're not just little mounds. They can extend for kilometers,
Speaker 3: winding across the landscape.
Speaker 2: It's like a long winding wall or a buckle in
Speaker 2: the pavement, just on a massive scale.
Speaker 3: That's a great way to think of it, a buckle
Speaker 3: in the lunar pavement. But what makes this study such
Speaker 3: a breakthrough isn't just identifying one or two of these.
Speaker 3: I mean, we've seen oddities before. It's the sheer volume,
Speaker 3: the number of them.
Speaker 2: I was looking at the data table and the report
Speaker 2: and the numbers are just startling. They identified eleven one
Speaker 2: hundred and fourteen new SMR segments.
Speaker 3: Just on the near side lunar Maria, the side that
Speaker 3: faces us.
Speaker 2: That's over a thousand geological features that we just we
Speaker 2: hadn't cataloged them before.
Speaker 3: We hadn't mapped them systematically, We didn't understand how widespread
Speaker 3: they were. And when you add these new findings to
Speaker 3: what was already suspected or known in isolation. The total
Speaker 3: count of these small mirror ridges across the Moon jumps
Speaker 3: to two thousand, six hundred thirty four.
Speaker 2: Two thousand, six hundred. That is a significant amount of wrinkling.
Speaker 2: That's not just a localized anomaly, that's a pattern.
Speaker 3: It completely changes the map. It strongly suggests a global
Speaker 3: process is at work.
Speaker 2: I have to pause on that for a second, though.
Speaker 2: I mean, we've been staring at the Moon with high
Speaker 2: powered telescopes for centuries. We've sent orbiters, we've literally had
Speaker 2: boots on the ground. Apollo astronauts walked on the mirror.
Speaker 2: How on earth did we miss over a thousand of
Speaker 2: these ridges.
Speaker 3: It's a combination of a few things, resolution, lighting, and frankly, attention.
Speaker 3: We knew about similar ridges in the Highlands. We'll get
Speaker 3: to those later. They're called obate scarps, right, But the
Speaker 3: prevailing assumption was that the Maria, those deep, thick lava
Speaker 3: planes were structurally different, maybe thicker, more stable, less prone
Speaker 3: to breaking.
Speaker 2: So we weren't really looking for them there.
Speaker 3: We weren't looking for them on this scale. Finding them
Speaker 3: widespread in the Maria is the game changer. Cole Nipe,
Speaker 3: the lead author, he emphasized this. He noted that this
Speaker 3: is the first time scientists have documented the widespread prevalence
Speaker 3: of these features throughout the lunar mare.
Speaker 2: So it's not that they were invisible and so we
Speaker 2: didn't realize they were everywhere, that it was a consistent pattern.
Speaker 3: Precisely. It's like looking at a smooth sheet of ice
Speaker 3: on a lake from a distance, it looks perfect. But
Speaker 3: if you get down on your hands and knees with
Speaker 3: a magnifying glass, or if you catch the light just
Speaker 3: right at sunset.
Speaker 2: Ah the lighting.
Speaker 3: The lighting is key. Low angle sunlight makes shadows that
Speaker 3: reveal subtle topography. You suddenly realize the whole sheet of
Speaker 3: ice is crisscrossed with tiny stress fractures and ridges.
Speaker 2: And those fractures tell you the ice is under pressure exactly.
Speaker 3: They tell you the ice is moving or changing shape,
Speaker 3: that it's not as stable as it looks, which.
Speaker 2: Leads us perfectly to the mechanism the why we have
Speaker 2: two six hundred and thirty four of these ridges. The
Speaker 2: moon is wrinkling, So why I thought the moon was
Speaker 2: a solid, frozen block of stone, And.
Speaker 3: Understand the why we have to do a little comparative planetology.
Speaker 3: It really helps to look at Earth versus the Moon.
Speaker 2: Okay, Earth versus Moon ding.
Speaker 3: Ding fight chuckles, It's less of a fight and more
Speaker 3: of a contrast in styles. Earth is driven by plate tectonics.
Speaker 3: We all learned about this in school. Our crust is
Speaker 3: broken into these massive puzzle pieces, the tectonic.
Speaker 2: Plates, right, the North American plate, Pacific plate, and so on.
Speaker 3: And they float on the semi molten mantle. They crash
Speaker 3: into each other to create the Himalayas, they pull apart
Speaker 3: to create the Atlantic Ocean. They slide past each other
Speaker 3: to create the San Andrea's fault. It's a chaotic, multi.
Speaker 2: Piece system, very dynamic.
Speaker 3: Everything is constantly moving and recycling. It's a very active surface.
Speaker 2: Right, dynamic puzzle where the pieces are always shuffling around.
Speaker 3: The Moon is different. The Moon is what we call
Speaker 3: a one plate body.
Speaker 2: One plate, so it's just a continuous solid shell.
Speaker 3: It's a single solid lithosphere. There are no other plates
Speaker 3: to crash into. It's like an orange peel that hasn't
Speaker 3: been sectioned yet, just one solid piece.
Speaker 2: So if there are no plates colliding, how do you
Speaker 2: get a ridge? How do you get a mountain? Usually
Speaker 2: a mountain is formed when two things smash together, right, Yeah,
Speaker 2: like cars in a head on collision. The hoods just
Speaker 2: buckle up.
Speaker 3: On Earth, yes, that's the primary mountain building process. But
Speaker 3: on the Moon, the ridges are formed because the Moon is.
Speaker 2: Shrinking, shrinking, It is getting physically smaller.
Speaker 3: The whole thing, the whole thing is contracting. Yes, its
Speaker 3: radius is slowly but measurably decreasing.
Speaker 2: Okay, help me with the physics here. It is it evaporating,
Speaker 2: Is it leaking mass into space or something.
Speaker 3: It's a much simpler process. Actually, it's thermal contraction. You
Speaker 3: have to remember the Moon was born in incredible violenceaing
Speaker 3: theory is the giant impact hypothesis, the big whack, the
Speaker 3: big whack, exactly, a Mars sized object smashed into the
Speaker 3: early Earth, and the debris from that collision eventually coalesced
Speaker 3: to form the Moon.
Speaker 2: So it started out hot, very hot.
Speaker 3: It started out molten a global magma ocean, and for
Speaker 3: the last four point five billion years it has been
Speaker 3: slowly radiating all that primordial heat out into the cold
Speaker 3: vacuum of space. It's cooling down, it's cooling down and
Speaker 3: as we know from basic physics, when most things cool down,
Speaker 3: they contract, they lose volume, and the atoms and molecules
Speaker 3: get closer together.
Speaker 2: So the hot interior is cooling and shriveling up like
Speaker 2: a balloon losing air.
Speaker 3: That's a good way to put it. But the crust,
Speaker 3: the outer shell, is hard rock. It's brittle. It cooled
Speaker 3: and hardened a long long time ago. So now you
Speaker 3: have this shrinking interior pulling away from a rigid crust
Speaker 3: that is already set in its size.
Speaker 2: So the shell is suddenly too big for the body
Speaker 2: inside it.
Speaker 3: That's a perfect description. I think the best analogy is
Speaker 3: the grape turning into a raisin. I was just thinking
Speaker 3: that as the pulp inside the grape dries out and shrinks,
Speaker 3: the skin suddenly has way too much surface area. It
Speaker 3: has to go somewhere. It can't dissolve, it can't just disappear.
Speaker 3: So what does it do. It buckles, It folds over
Speaker 3: on itself to take up the extra space.
Speaker 2: And that folds that's the ridge, that is the ridge.
Speaker 3: In geology we call this a thrust fault. The crust
Speaker 3: is being put under immense global compression. It's being squeezed
Speaker 3: from all sides until the rock literally snaps. One section
Speaker 3: of the ground is thrust up and over the adjacent
Speaker 3: section to accommodate the smaller surface area.
Speaker 2: That is such a powerful image. The Moon is literally
Speaker 2: crushing its own surface because it's imploding in slow motion.
Speaker 3: Imploding might be a bit dramatic for the timescale, but
Speaker 3: contracting is stot on. It is a global squeeze and
Speaker 3: the numbers are pretty impressive. Scientists estimate the Moon has
Speaker 3: shrunk by about one hundred and fifty feet roughly fifty
Speaker 3: meters in radius over the last several hundred million years.
Speaker 2: One hundred and fifty feet. You know, that doesn't sound
Speaker 2: like a lot for a body of this size of
Speaker 2: the Moon.
Speaker 3: It sounds small, But think about the energy required to
Speaker 3: compress a solid ball of rock that's over two thousand
Speaker 3: miles in diameter by one hundred and fifty feet. That
Speaker 3: is a tremendous amount of stored stress energy that has
Speaker 3: to be released, and it releases it by breaking the rock.
Speaker 2: Which creates these faults. Now, the study makes a distinction
Speaker 2: here that I want to clarify. We're talking about smr's
Speaker 2: small mare ridges, But you mentioned earlier that we already
Speaker 2: knew about ridges in the highlands. The study calls those
Speaker 2: low bait scarps. Is there a real difference or is
Speaker 2: this just scientists loving different names for the same thing.
Speaker 3: It's a great question. It's a distinction in geography mostly,
Speaker 3: but not really in mechanism.
Speaker 2: Break that down for me.
Speaker 3: So, low bate scarps are found in the highlands, the
Speaker 3: ancient rocky mountainous terrain. We've known about those since the
Speaker 3: Apollo missions. We've seen them, we've mapped them. They look
Speaker 3: like big stair steps or cliffs in the landscape.
Speaker 2: Okay, so they're the highland version.
Speaker 3: Exactly, and SMRs are essentially the same type of feature.
Speaker 3: They're just in the Maria the basalt lava planes.
Speaker 2: Okay, so it's just about where they are located. It's
Speaker 2: like calling a sandwich a sub in one city and
Speaker 2: a hoogee in another. It's the same thing.
Speaker 3: That's a fair analogy, and the key finding from this
Speaker 3: analysis by Nipeverr and Waters is that it confirms they
Speaker 3: are formed by the exact same type of faults. They
Speaker 3: are both thrust falls. They are caused by the exact
Speaker 3: same global contractional forces.
Speaker 2: It's the same squeeze just happening in different types of rock.
Speaker 3: It is, and here is the smoking gun, the real clincher.
Speaker 3: The study found instances where a low bit scarp in
Speaker 3: the mountains travels down a slope, hits the flat mare,
Speaker 3: and transitions directly into an smr.
Speaker 2: Oh wow. So it's one continuous crack running from the
Speaker 2: mountains right into the sea.
Speaker 3: So to speak, exactly, it's a single fault system that
Speaker 3: completely ignores the terrain boundary. And this is powerful evidence
Speaker 3: because it confirms that the shrinking isn't localized. It's not
Speaker 3: just something happening in the old mountains. It's a global contraction.
Speaker 3: The entire Moon is tightening its belt.
Speaker 2: That answers the and the why. But I really want
Speaker 2: to talk about the when, because you know, recent in
Speaker 2: geology usually means like a billion years ago. Scientists have
Speaker 2: a totally warped sense of time compared to the rest
Speaker 2: of us. How fresh are these wrinkles?
Speaker 3: This is one of the most exciting parts of the
Speaker 3: study for me. The dating.
Speaker 2: Okay, so how do you date a wrinkle on the
Speaker 2: Moon without actually landing on it and taking a rock sample.
Speaker 2: We don't have carbon dating for rocks from orbit.
Speaker 3: No, we don't. We use a clever technique called crater counting.
Speaker 3: It's one of the most fundamental tools in planetary science.
Speaker 2: Right, walk us through that logic.
Speaker 3: It's based on probability and a classic geological principle, the
Speaker 3: law of superposition. The Moon, like anybody in the Solar System,
Speaker 3: is constantly being bombarded by meteoroids, big ones, small ones,
Speaker 3: tiny micromedioroids, over billions of years. Surfaces accumulate craters like
Speaker 3: a sidewalk accumulates gum.
Speaker 2: Gross but a very effective image.
Speaker 3: A very old surface like the Highlands will be absolutely
Speaker 3: covered in craters. It's saturated. You can't make a new
Speaker 3: crater without destroying an old one. A brand new surface,
Speaker 3: like a fresh lava flow, will be smooth and almost pristine.
Speaker 2: Okay, more plock marks equals older skin.
Speaker 3: That makes sense exactly. Now. You look at the relationship
Speaker 3: between the ridge and the craters around it. If you
Speaker 3: have a ridge an smr and it cuts through a
Speaker 3: small crater, distorting it or breaking it in half, what
Speaker 3: does that tell you?
Speaker 2: It tells you the ridge formed after the crater.
Speaker 3: The ridge is younger, precisely. But if there are tiny,
Speaker 3: fresh looking craters sitting on top of the ridge and
Speaker 3: they are undisturbed, perfectly round little bowls, then the ridge
Speaker 3: must have formed before those craters hit.
Speaker 2: It's a game of geological layering who is on top
Speaker 2: of whom it is.
Speaker 3: And by carefully counting the density and size of craters
Speaker 3: on and around these ridges and plugging that into models
Speaker 3: of how often craters of a certain sized form, the
Speaker 3: team was able to calculate an average model age and
Speaker 3: the numbers are Ah, they're shocking.
Speaker 2: Okay, hit me with the numbers.
Speaker 3: The average age of these small marre ridges is roughly
Speaker 3: one hundred and twenty four million years one hundred twenty
Speaker 3: four million and for comparison, the low bit scarps in
Speaker 3: the Highlands, which Tom Waters had previously analyzed, have a
Speaker 3: similar average age of about one hundred and five million years.
Speaker 2: Okay, I need you to contextualize this for me. To me,
Speaker 2: a human who hopes to live to maybe ninety one
Speaker 2: hundred and twenty four million years sounds incredibly ancient. That's
Speaker 2: the Cretaceous period on Earth, dinosaurs were walking around.
Speaker 3: It feels like an eternity to us. But you have
Speaker 3: to shift your perspective to geological time to cosmic time.
Speaker 3: The Moon is about four point five billion.
Speaker 2: Years old, right, so forty five hundred million years exactly.
Speaker 3: So if you imagine the Moon's entire life as a
Speaker 3: twenty four hour clock from its formation at midnight to
Speaker 3: the present day, one hundred million years is the last
Speaker 3: half hour, maybe even less. It's the last few minutes
Speaker 3: before the clock strikes.
Speaker 2: Now, Oh wow, Okay, that puts it in perspective.
Speaker 3: These features represent the last what two or three percent
Speaker 3: of the Moon's entire history in geological time. These are
Speaker 3: fresh wounds. They are very likely the youngest tectonic features
Speaker 3: on the entire lunar body.
Speaker 2: So when we look at the Moon, we aren't just
Speaker 2: seeing ancient scars from its violent birth. We aren't just
Speaker 2: seeing the bombardment from the early Solar system. We are
Speaker 2: seeing things that happened well yesterday in space terms.
Speaker 3: And the really big implication of that youth is that
Speaker 3: the process is likely still forming them.
Speaker 2: That's the kicker, isn't it. An average age of one
Speaker 2: hundred million years doesn't mean they all formed and then
Speaker 2: stopped one hundred million years ago. It means the process
Speaker 2: that made them has been active in the very recent
Speaker 2: past and is in all probability ongoing.
Speaker 3: The Moon is still cooling, we know that from thermal models. Therefore,
Speaker 3: it is still shrinking. Therefore, the stress is still building
Speaker 3: up in the crust. Therefore the crust is still cracking.
Speaker 2: Right, which brings us to the part of the conversation
Speaker 2: that sounds a bit like a disaster movie. If the
Speaker 2: crust is snapping to make these ridges, that snap must
Speaker 2: release a lot of energy. When rock breaks under that
Speaker 2: much pressure, it's not quiet.
Speaker 3: It creates seismic activity.
Speaker 2: Moonquakes, moonquakes.
Speaker 3: Absolutely.
Speaker 2: We've all heard of earthquakes. We know about the devastation
Speaker 2: they can cause here. But moonquakes are a real, documented phenomena.
Speaker 3: Oh, they are very real. The Apollo astronauts actually placed
Speaker 3: seismometers on the lunar surface Apollo eleven, twelve, fourteen, fifteen,
Speaker 3: and sixteen all left working instruments behind. They formed a network.
Speaker 2: I remember seeing pictures of those.
Speaker 3: And they recorded thousands of seismic events between nineteen sixty
Speaker 3: nine and nineteen seventy seven when they were finally turned
Speaker 3: off to save money.
Speaker 2: And this new study connects those recorded quakes to these ridges.
Speaker 3: It solidifies the connection yes, there are different types of moonquakes.
Speaker 3: Some are very deep caused by the tidal pull of
Speaker 3: Earth's gravity. But the shallow ones, the ones that happen
Speaker 3: in the upper crust, those are the dangerous ones.
Speaker 2: And those are the tectonic ones.
Speaker 3: Those are the tectonic ones. And Tom Waters, one of
Speaker 3: the authors of this new study had previously done work
Speaker 3: that linked the low bait scarps in the Highlands to
Speaker 3: some of the wrongest shallow moonquakes recorded by the Apollo network.
Speaker 3: He basically triangulated the epicenters of the quakes to these
Speaker 3: known faults.
Speaker 2: Okay, so we knew the highland scarps were seismically active,
Speaker 2: but now we have this new map.
Speaker 3: Now we have eleven and fourteen new ridges cataloged in
Speaker 3: the Maria, which we now know are the same type
Speaker 3: of feature.
Speaker 2: So the safe zone isn't safe.
Speaker 3: That is the critical takeaway. Previously, mission planners looked at
Speaker 3: the Marie and thought perfect flat stable, easy to land on,
Speaker 3: no cliffs a crash into, no mountains to navigate. But
Speaker 3: now we know that SMRs are widespread there and they
Speaker 3: are formed by the exact same mechanism that causes powerful
Speaker 3: quakes in the Highlands.
Speaker 2: So basically, anywhere there is a wrinkle on this new map,
Speaker 2: there is a potential epicenter for a future meanquake.
Speaker 3: That's right, any place with an SMR has to be
Speaker 3: considered a potential source of shallow seismic activity, and we
Speaker 3: just found out they are all over the place, including
Speaker 3: many of the areas considered prime landing spots.
Speaker 2: This really complicates things for the Artemis program.
Speaker 3: It complicates things for anyone planning to stay on the
Speaker 3: Moon for longer than a few days, for any kind
Speaker 3: of permanent or semi permanent presence.
Speaker 2: We are talking about building permanent bases, human habitats, landing pads,
Speaker 2: mining operations, power stations.
Speaker 3: And this is explicitly mentioned in the study. Cole Naipevier
Speaker 3: pointed this out directly. He said, and I'm paraphrasing, that
Speaker 3: a better understanding of lunar tectonics and seismic activity will
Speaker 3: directly benefit the safety and scientific success of Artemis and
Speaker 3: all future missions.
Speaker 2: It's moving this whole field from academic curiosity to active
Speaker 2: risk assessment for human lives.
Speaker 3: Think about the engineering challenges. You are building a pressurized habitat.
Speaker 3: It needs to be perfectly air tight, it's essentially a
Speaker 3: balloon made of metal or advanced composite material holding a precious,
Speaker 3: breathable atmosphere against a hard vacuum.
Speaker 2: Right, you do not want your balloon to start shaking violently.
Speaker 3: You definitely don't. But there's a key difference between earthquakes
Speaker 3: and moonquakes that it makes this even scarier for engineers.
Speaker 2: How so, is the shaking more powerful a higher magnitude.
Speaker 3: Not necessarily the magnitude, it's the duration. The duration, the duration.
Speaker 3: Here on Earth, if a big earthquake hits, it's violent,
Speaker 3: it's terrifying, but it usually dissipates relatively quickly, maybe thirty
Speaker 3: seconds a minute, maybe two minutes of strong shaking. The
Speaker 3: longest ones might feel like forever, but they are over
Speaker 3: in a matter of minutes.
Speaker 2: Okay, And why is that?
Speaker 3: Because Earth is wet, we have oceans, we have groundwater,
Speaker 3: we have a semi molten mantle. All that liquid, that
Speaker 3: fluid material absorbs and dampens the seismic energy. It acts
Speaker 3: like a giant shock absorber or a layer of soundproofing.
Speaker 3: It did into the vibration, It dends it very effectively.
Speaker 3: The Moon, on the other hand, is bone dried it's rigid.
Speaker 3: It's cold, brittle rock all the way down. So when
Speaker 3: it quake hits, that seismic energy has nowhere to go.
Speaker 3: There's nothing to absorb it. It just bounces around inside
Speaker 3: the crust, reflecting off the surface and the interior layers,
Speaker 3: over and over again. The moon, it rings, It rings
Speaker 3: like a bell or gong. The Apollo seismic data showed
Speaker 3: that shallow moonquakes, the kind caused by these thrust faults
Speaker 3: can last.
Speaker 2: For hours hours. You're not serious.
Speaker 3: I'm completely serious. High frequency shaking continuing for an hour
Speaker 3: or more is not out of the question for a
Speaker 3: significant event. Imagine a magnitude five quake that just keeps
Speaker 3: going and going and going.
Speaker 2: That is an absolute nightmare scenario. Imagine you're in a
Speaker 2: lunar base. It's the pitch black of a two week
Speaker 2: long lunar night, and the ground starts vibrating and just
Speaker 2: doesn't stop.
Speaker 3: It creates massive issues for structural fatigue. Any material, no
Speaker 3: matter how strong, will degrade when you vibrate it for
Speaker 3: that long. Seals can fail, microfractures can grow into critical failures.
Speaker 2: What about the dust. I know that lunar dest is
Speaker 2: supposed to be incredibly sharp and nasty, like tiny shards
Speaker 2: of glass.
Speaker 3: Oh. Absolutely. The regolithe is a huge problem already because
Speaker 3: it's so abrasive and it sticks to everything electrostatically. If
Speaker 3: you shake the ground vigorously for an hour, you are
Speaker 3: mobilizing that dust. You could create a persistent, low gravity
Speaker 3: dust cloud that could coat solar panels, rendering them useless,
Speaker 3: or jam airlocks and moving parts.
Speaker 2: It really changes the real estate value of the Maria,
Speaker 2: doesn't it. You can't just pick a flat spot anymore.
Speaker 2: You have to pull up this new tectonic map first.
Speaker 3: You have to you have to identify the SMRs and
Speaker 3: give them a very wide berth. You do not want
Speaker 3: to build your billion dollar habitat on top of a
Speaker 3: fault line that is actively engaging in crustal compression.
Speaker 2: It's wild to think about. We always worry about the
Speaker 2: big obvious space dangers, radiation or lack of air or
Speaker 2: the extreme cold, but we rarely discuss the ground itself
Speaker 2: opening up or rather shifting violently beneath our feet.
Speaker 3: It adds a whole new layer of due diligence to
Speaker 3: the site selection process that is absolutely critical. We need
Speaker 3: to define seismic exclusion zones around these features.
Speaker 2: So, looking at this study as a whole, what it
Speaker 2: really provides is a catalog. It's a comprehensive map of
Speaker 2: these danger zones.
Speaker 3: It is a comprehensive catalog of global contractional features. Yes,
Speaker 3: it's a foundational piece of.
Speaker 2: Work, and it was all done using data from the LROC.
Speaker 2: Is that right?
Speaker 3: That's right. The Lunar Reconnaissance Orbiter Camera LRO has been
Speaker 3: circling the Moon since two thousand and nine taking these
Speaker 3: incredible high resolution images. It's mapped the Moon in better
Speaker 3: detail than we have mapped some parts of the ocean
Speaker 3: floor right here on Earth.
Speaker 2: I just want to take a moment to appreciate the
Speaker 2: sheer grunt work involved here. These researchers, Niberver and Waters
Speaker 2: and their team didn't just push a button and have
Speaker 2: an AI find these things. They manually mapped over two
Speaker 2: thousand of these tiny ridges.
Speaker 3: It is meticulous, painstaking work. It requires a highly trained eye.
Speaker 3: You have to be able to look at these images,
Speaker 3: often with different lighting conditions, and distinguish a subtle tectonic
Speaker 3: ridge from a crater rim or a lava tube collapse
Speaker 3: or some other feature. It's a monumental effort.
Speaker 2: But that labor is what completes the global picture that
Speaker 2: seems to be the consensus here. We aren't just looking
Speaker 2: at isolated oddities in the Highlands anymore. We are seeing
Speaker 2: a single, unified planetary process.
Speaker 3: That's the key. The Moon is cooling, the Moon is contracting,
Speaker 3: and as a result, the crust is breaking, and it
Speaker 3: is happening everywhere Hylands and Maria alike.
Speaker 2: It's foundational science, you know. It's the kind of work
Speaker 2: that doesn't always make the front page of the newspaper
Speaker 2: because it's not a flashy explosion or a discovery of
Speaker 2: a new alien. But it's the work that keeps future
Speaker 2: astronauts alive.
Speaker 3: It's the safety manual. You can't write the safety manual
Speaker 3: for a new territory until you understand the hazards. The
Speaker 3: study is a critical chapter in that manual.
Speaker 2: As we wrap up this discussion, I have to say
Speaker 2: my view of the Moon has definitely shifted. I think
Speaker 2: for a lot of our listeners it probably has too.
Speaker 3: In what way has it shifted for you?
Speaker 2: Well, you know, like we said at the start, I
Speaker 2: looked at it as a night light, a beautiful but
Speaker 2: ultimately static object, magnificent desolation, as buz Aldrin so famously
Speaker 2: called it. But desolation implies that nothing is happening. It
Speaker 2: implies stillness.
Speaker 3: And that's the great misconception, and we're overturning it is now.
Speaker 2: When I look up at it, I'm going to think
Speaker 2: about that cooling process. I'm going to picture that interior
Speaker 2: shrinking and the crust buckling under the strain. It's like
Speaker 2: the Moon is still settling into its old age. It's shivering.
Speaker 3: That's a beautiful, if slightly unsettling way to put it.
Speaker 3: It is shivering, it is shrinking, It is cooling, and
Speaker 3: it is quaking. It is a body trying to find
Speaker 3: a comfortable, stable position as it loses its primordial internal warmth.
Speaker 2: We've really moved from looking at the Moon as a
Speaker 2: fossil to looking at it as a dynamic world with
Speaker 2: its own internal life. It might be a very slow
Speaker 2: life compared to Earth's frantic tectonic shifting, but it's there.
Speaker 3: The pulse is there, and we are just beginning to
Speaker 3: understand it. The more we look and the better our
Speaker 3: instruments get, the more we find it's still a world
Speaker 3: of secrets.
Speaker 2: Here's the thought to leave you with and it's been
Speaker 2: on my mind through this whole conversation. We talk so
Speaker 2: much about becoming a multiplanetary species, about colonizing space, we
Speaker 2: talk about terraforming, about bending these other worlds to our will.
Speaker 2: But this study is such a humble reminder that we
Speaker 2: don't control these worlds.
Speaker 3: No, we certainly do not. We are guests at best.
Speaker 2: The Moon doesn't care about our landing schedules or our
Speaker 2: habitat designs. It's going to keep shrinking and it's going
Speaker 2: to keep shaking whether we are there or not.
Speaker 3: Geology always wins in the end. It operates on time
Speaker 3: scales we can barely comprehend.
Speaker 2: So if we are serious about planning to live there,
Speaker 2: we have to answer a very very difficult question. How
Speaker 2: do we engineer buildings and infrastructure for a world that
Speaker 2: is slowly inexorably crushing itself.
Speaker 3: That is the engineering challenge of the century for lunar exploration.
Speaker 2: The ground beneath the feet of future astronauts is simply
Speaker 2: not as solid as we once thought. It just makes
Speaker 2: you realize that even on a dead rock, nature is
Speaker 2: still very much in charge.
Speaker 3: Indeed, it is a powerful reminder.
Speaker 2: Thank you so much, for joining us on this exploration
Speaker 2: of lunar tectonics. It's been a fascinating look at the
Speaker 2: hidden and very active life of our nearest neighbor. It
Speaker 2: really has pa keep looking up.
Speaker 3: Take care,