20 Billion Stars and Counting - NASA's Quest to Map Our Entire Galaxy

<v Speaker 1>Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
<v Speaker 1>with our soothing Bedtime Astronomie podcast. Each episode offers a
<v Speaker 1>gentle journey through the stars, planets, and beyond, perfect for
<v Speaker 1>unwinding after a long day. Let's travel through the mysteries
<v Speaker 1>of the universe as you drift off into a peaceful
<v Speaker 1>slumber under the night sky.
<v Speaker 2>Have you ever looked up at the night sky and
<v Speaker 2>just wondered what secrets our own galaxy? The Milky Way
<v Speaker 2>truly holds? I mean it really holds. What if I
<v Speaker 2>told you there's this invisible cosmic fog out there and
<v Speaker 2>it's hiding some of its biggest mysteries. But a new
<v Speaker 2>mission is about to cut right through it give us
<v Speaker 2>a view we've well only dreamed of. Today, we're really
<v Speaker 2>getting into the ambitious journey of NASA's Nancy Grace Roman
<v Speaker 2>Space Telescope. And look, this isn't just another launch, you know,
<v Speaker 2>it's a mission specifically designed to reveal our home galaxy
<v Speaker 2>through the very stuff that's always hidden it. Klose mcdust,
<v Speaker 2>We're talking about an unprecedented exploration. How Roman will use
<v Speaker 2>this seemingly everyday material cosmic dust to paint a three
<v Speaker 2>dimensional picture of the Milky Way, something far beyond anything
<v Speaker 2>we've managed before. You've shared some really fascinating material from
<v Speaker 2>NASA's Goddard Space Flight Center, really digging into Roman's capabilities
<v Speaker 2>at Scalactic Plane Survey. Our goal today is to unpack
<v Speaker 2>the most exciting parts of this whole thing. We want
<v Speaker 2>you to understand, not just what Roman will do, but
<v Speaker 2>why it matters, why it matters so much to us
<v Speaker 2>right here on Earth, and what incredible insights it might
<v Speaker 2>unlock about well, our cosmic neighborhood.
<v Speaker 3>It really is an exciting prospect because Roman it isn't
<v Speaker 3>just another telescope we're adding to the collection. It's specifically engineered,
<v Speaker 3>really designed to tackle this fundamental, long standing challenge in astronomy,
<v Speaker 3>seeing through that obscuring dust that is always shaped and
<v Speaker 3>honestly limited our view of the galaxy. For decades, you know,
<v Speaker 3>we've been piecing together clues hints, but the ructure, the
<v Speaker 3>architecture of our home galaxy, it's remained shrouded. And this
<v Speaker 3>raises a huge question for all of us, doesn't it?
<v Speaker 3>Just how much more about our own galaxy have we
<v Speaker 3>been missing all this time. Yeah, and what might that
<v Speaker 3>unseen picture actually reveal.
<v Speaker 2>That really is the crux of it. Yeah, and this
<v Speaker 2>leads us right into understanding that the invisible fabric of
<v Speaker 2>our galaxy with scientists call the interstellar medium, or the
<v Speaker 2>ism you see when you look out at the vastness
<v Speaker 2>between the stars and there are more than one hundred
<v Speaker 2>billion stars in the Milky Way, those spaces, they aren't empty,
<v Speaker 2>even though you know they look that way to our eyes.
<v Speaker 3>Exactly, They're filled with this diffuse but incredibly important stuff.
<v Speaker 3>The interstellar medium mostly gas, hydrogen and helium, mainly the
<v Speaker 3>most common stuff in the universe, but crucially, it also
<v Speaker 3>contains these tiny solid particles dust dust. And while the
<v Speaker 3>gas makes up most of the mass, it's often this
<v Speaker 3>dust that plays the really intriguing and let's be honest,
<v Speaker 3>for astronomers, the most frustrating role. This cosmic dust. Even
<v Speaker 3>though it' seen so sparse, it's incredibly good at blocking
<v Speaker 3>our view.
<v Speaker 2>And that's the paradox, isn't it. This dust which is
<v Speaker 2>so good at hiding things from us, It's also deeply
<v Speaker 2>connected to the cycles of life and death in the galaxy.
<v Speaker 3>Absolutely, what's truly fascinating is. It's dual nature. It's simultaneously
<v Speaker 3>the raw material, you could say, the seeds of new stars,
<v Speaker 3>and at the same time it's the remnants, the leftover
<v Speaker 3>crumbs from stars long dead. Oh okay, so you have
<v Speaker 3>this incredible continuous galactic recycling system going on. Think of
<v Speaker 3>it like a cosmic circular economy maybe, where the building
<v Speaker 3>blocks for new stars new planets are constantly being made
<v Speaker 3>from the ashes of old ones. It's this grand cycle
<v Speaker 3>that keeps renewing the galaxy, that.
<v Speaker 2>Cosmic recycling idea that really clicks. But while this dual
<v Speaker 2>role is obviously vital for how galaxies evolve, for us
<v Speaker 2>trying to see things from inside the galaxy, this seemingly
<v Speaker 2>thin dust is just a massive challenge. It's like if
<v Speaker 2>you were trying to map a dense forest, right, but
<v Speaker 2>every time you tried to look far ahead, this thick,
<v Speaker 2>constant fog rolled in. That's basically the problem astronomers have.
<v Speaker 2>These dust clouds make it incredibly difficult to map the
<v Speaker 2>fine details of our galaxy, especially when we try to look,
<v Speaker 2>say towards the other side from where we are. It's
<v Speaker 2>like having this huge galactic blind spot stretching tens of
<v Speaker 2>thousands of light years across large parts of our own
<v Speaker 2>home are still.
<v Speaker 3>A mystery exactly. Imagine trying to get a clear picture
<v Speaker 3>of a whole city, but you're standing right in the
<v Speaker 3>middle of its downtown square, and all the distant buildings,
<v Speaker 3>the suburbs, they're just covered in this constant smog. Yeah,
<v Speaker 3>you can see the nearby stuff, okay, the immediate structures,
<v Speaker 3>but anything further out just gets blurry, indistinct, or totally hidden.
<v Speaker 3>That's our situation in the Milky Way. We're embedded right
<v Speaker 3>inside the disk of our own spiral galaxy, and the
<v Speaker 3>dust it's particularly thick in that galactic plane right where
<v Speaker 3>we live, right where we live. So while we can
<v Speaker 3>see nearby stars and structures pretty clearly, our view gets
<v Speaker 3>incredibly blocked and distorted the moment we try to peer
<v Speaker 3>through those denser regions or just further away.
<v Speaker 2>And this limitation has meant that for ages, scientists have
<v Speaker 2>been trying to piece together what the Milky Way likely
<v Speaker 2>looks like using a sort of cosmic guesswork. They combine
<v Speaker 2>the observations we can make nearby with what they see
<v Speaker 2>in other spiral galaxies, galaxies we see from the outside
<v Speaker 2>edge on or face on.
<v Speaker 3>Looking at analogs.
<v Speaker 2>Exactly, they guess what our galaxy probably looks like based
<v Speaker 2>on these distant cosmic cousins. It's an educated guess, for sure,
<v Speaker 2>a very educated one, but it's still like an artist's
<v Speaker 2>impression when what we really want is the architect's blueprint.
<v Speaker 2>You know, we're trying to understand the whole house, but
<v Speaker 2>we're stuck in one room and all the windows are
<v Speaker 2>just covered in dust. It's a frustrating perspective sometimes, So
<v Speaker 2>how do we ever hope to map our own galaxy
<v Speaker 2>properly when we're looking through this constant cosmic haze. This
<v Speaker 2>is exactly where the Nancy Grace Roman Space Telescope comes in.
<v Speaker 2>It offers this truly breakthrough vision, promising to just slice
<v Speaker 2>right through that cosmic fog. And Roman's big innovation here
<v Speaker 2>is harnessing the power of infrared light. Now, for anyone
<v Speaker 2>not familiar, infrared light is basically light with longer wavelengths
<v Speaker 2>than our eyes can see. It sits just beyond the
<v Speaker 2>red end of the visible spectrum that we perceive. We
<v Speaker 2>can't see it directly, but it carries a ton of
<v Speaker 2>information about the universe, especially when visible light gets blocked, and.
<v Speaker 3>The real genius of using infrared lies in how it
<v Speaker 3>physically interacts, or rather doesn't interact as much with cosmic dust.
<v Speaker 3>The longer the wavelengths of light, the more likely it
<v Speaker 3>is to just pass right through a dust cloud without
<v Speaker 3>getting scattered all over the place like visible light does.
<v Speaker 2>Okay, so longer waves just push through better.
<v Speaker 3>Sort of think of it like this. Imagine tiny ripples
<v Speaker 3>on a pond hitting a small pebble. Those short, choppy ripples,
<v Speaker 3>they'll break up scatter quite a bit. But now imagine
<v Speaker 3>a long rolling ocean wave hitting that same pebble. It
<v Speaker 3>might pass right over it relatively undisturbed. I can picture
<v Speaker 3>that visible light, especially the bluer order wavelengths, acts more
<v Speaker 3>like those choppy ripples. When it hits typical dust grains,
<v Speaker 3>it scatters easily, and that's why dust clouds look dark
<v Speaker 3>and opaque to our regular telescopes. They're blocking and scattering
<v Speaker 3>the light coming from behind them.
<v Speaker 2>That's a great way to put it. So the shorter wavelength,
<v Speaker 2>like the blue light from hot young stars, those are
<v Speaker 2>the choppy ways This blue light more easily scatters, As
<v Speaker 2>the material says, when it hits the dust, and that
<v Speaker 2>scattering effect is why those dust clouds look so dark
<v Speaker 2>and visible light pictures that they're just soaking up or
<v Speaker 2>bouncing away that light.
<v Speaker 3>And this scattering leads to a really crucial effect something
<v Speaker 3>Roman will really exploit. Stars shining through dust appear dimmer
<v Speaker 3>and redder than they actually are.
<v Speaker 2>Oh okay, redder, Yeah, redder.
<v Speaker 3>The blue light from the star gets scattered away much
<v Speaker 3>more effectively by the dust, leaving mostly the redder longer
<v Speaker 3>wavelengths to actually reach our telescopes. This reddening isn't just
<v Speaker 3>a color change, it's a direct signature. It tells us
<v Speaker 3>the dust is there and gives us clues about its properties.
<v Speaker 2>Like looking at a sunset through our own.
<v Speaker 3>Atmosphere, exactly like that, the blue light gets scattered away
<v Speaker 3>by the air molecules, leaving the sun looking orange and red. Roman,
<v Speaker 3>by observing across a whole range of infrared wavelengths, can
<v Speaker 3>measure precisely how much the light is reddened in each
<v Speaker 3>different infrared band, and that acts like a unique fingerprint,
<v Speaker 3>telling us about the specific sizes and maybe even the
<v Speaker 3>composition of the dust in that direction. It basically gives
<v Speaker 3>us a window through the haze.
<v Speaker 2>So it's not just about seeing through the dust, but
<v Speaker 2>actually reading the dust itself, deciphering its properties based on
<v Speaker 2>how it changes the light precisely.
<v Speaker 3>That's the really clever part.
<v Speaker 2>And that's where this mission gets even more exciting, right,
<v Speaker 2>unlocking the dust's own characteristics and then using that info
<v Speaker 2>to build these incredibly detailed three D maps of our galaxy.
<v Speaker 3>So the basic technique, as I understand it, involves astronomers
<v Speaker 3>comparing Roman's infrared observations with what they already know or
<v Speaker 3>can model about the star itself. It's intrinsic characteristics. Right.
<v Speaker 2>We have pretty good models and observations from others that
<v Speaker 2>tell us a lot about how bright a star should be,
<v Speaker 2>what its color should be, based on its type, its temperature,
<v Speaker 2>its age.
<v Speaker 3>That kind of thing. Okay, so you have a baseline.
<v Speaker 2>Exactly a baseline. Then by measuring exactly how that star's
<v Speaker 2>light has been changed by the dust it traveled through,
<v Speaker 2>how much dimmer it is, how much redder it is
<v Speaker 2>across those different infrared wavelength astronomers can start to untangle
<v Speaker 2>that data. The critical goal, as the NASA material puts it,
<v Speaker 2>is to disentangle the star's distance from how much its
<v Speaker 2>colors have been reddened.
<v Speaker 3>Which sounds tricky because a star could look dim just
<v Speaker 3>because it's really far away, right, or because there's a
<v Speaker 3>lot of dust in the way. That's the challenge. But
<v Speaker 3>by using Roman's multi wavelength infrared data and combining it
<v Speaker 3>with our knowledge of the star's inherent properties, maybe from
<v Speaker 3>looking at its spectrum, which tells you its type and
<v Speaker 3>thus it's true brightness, they can separate those two effects.
<v Speaker 3>This lets them figure out the specific properties of the
<v Speaker 3>dust itself, giving is a much clearer, much more accurate
<v Speaker 3>p make sure of how the dust is distributed. Okay,
<v Speaker 3>got it, And this is where the details get really powerful.
<v Speaker 3>Brandon Hensley, a scientist studying interstellar dust, explains it really well.
<v Speaker 3>He points out that by asking how much redder and
<v Speaker 3>dimmer is the starlight that ROMAN detects at different wavelengths,
<v Speaker 3>you know, across its different filters, we can then take
<v Speaker 3>that information and relate it directly back to the properties
<v Speaker 3>of the dust grains themselves, and in particular their size.
<v Speaker 3>Their size. Wow, yeah, there's size. This is a critical insight.
<v Speaker 3>Think about trying to figure out what's in a fog
<v Speaker 3>bank without actually touching it different sized dust grains, tiny
<v Speaker 3>smoke like particles versus larger pollen like grains. The effect
<v Speaker 3>light in slightly different ways. By analyzing how much reddening
<v Speaker 3>happens at each of Roman's infrared wavelengths, scientists can actually
<v Speaker 3>deduce the average size of the dust grains in that
<v Speaker 3>specific direction. It's incredible detail about the very fabric of
<v Speaker 3>the ism.
<v Speaker 2>That's amazing. And it goes beyond just size too.
<v Speaker 3>Oh yeah, the insights go well beyond just particle side.
<v Speaker 3>Scientists will also learned about the dust's chemical makeup. Is
<v Speaker 3>it mostly silicates like tiny grains of sand, or is
<v Speaker 3>it carbonaceous stuff more like soda or graphite. Each composition
<v Speaker 3>interacts with infrared light a bit differently, leaving its own
<v Speaker 3>subtle signature. And even more than that, they'll be able
<v Speaker 3>to investigate the physical processes behind changing dust properties. So
<v Speaker 3>how does dust evolve over time? How is it made
<v Speaker 3>by dying stars, may be destroyed by supernova shockwaves, or
<v Speaker 3>changed as it floats around in the galaxy. These are
<v Speaker 3>the fundamental details we need to really understand the raw
<v Speaker 3>material of our galaxy and really all galaxies.
<v Speaker 2>Okay, now here's where it gets really interesting. I mean
<v Speaker 2>this sounds like a genuine paradigm shift. By collecting all
<v Speaker 2>this incredibly fine grained information, the reddening, the dimming, the
<v Speaker 2>dust grain size, the composition from literally, as the source says,
<v Speaker 2>billions and billions more stars. Astronomers can then piece together
<v Speaker 2>all these individual data points get giant cosmic pointless painting.
<v Speaker 2>And this incredible feat will let them construct detailed three
<v Speaker 2>D dust maps of the Milky Way. Just think about
<v Speaker 2>that for a second. Not just a flat picture, but
<v Speaker 2>a truly volumetric understanding of where the dust is, how
<v Speaker 2>dense it is, what it's made of, how it varies
<v Speaker 2>throughout huge regions of our galaxy.
<v Speaker 3>It's like going from looking at a two D photograph
<v Speaker 3>to having a fully explorable holographic model.
<v Speaker 2>It's that kind of leap, exactly a hologram of the
<v Speaker 2>Milky Way's dust, and.
<v Speaker 3>This leads directly to what Catherine Zucker, an astrophysicist involved
<v Speaker 3>in this, described as a total game changer. These maps
<v Speaker 3>will enable scientists to create a model of the Milky Way,
<v Speaker 3>which will show us how it looks from the outside.
<v Speaker 2>From the outside, that's the dream, isn't it.
<v Speaker 3>It really is. This is a critical leap because for
<v Speaker 3>the first time, we'll have a data driven blueprint of
<v Speaker 3>our own galaxy. Imagine being able to actually see our
<v Speaker 3>entire galactic home, its spiral arms, its central bar, its
<v Speaker 3>dusty lanes, all laid out in front of us, as
<v Speaker 3>if we were looking at it from say, the Andromeda galaxy. Wow,
<v Speaker 3>this kind of clarity, will find it is properly compare
<v Speaker 3>the Milky Way with all those other galaxies we only
<v Speaker 3>ever see from afar. It helps us, as Zucker says,
<v Speaker 3>slot it into a cosmological perspective of galaxy evolution. It's
<v Speaker 3>incredibly hard to figure out your place in the grand
<v Speaker 3>scheme of things if you don't even have a clear
<v Speaker 3>picture of your own home.
<v Speaker 2>And the sheer ambition the scale of this whole thing,
<v Speaker 2>it's just mind boggling. Frankly, Catherine Zucker really emphasized that
<v Speaker 2>Roman will add a whole new dimension to our understanding
<v Speaker 2>of the galaxy because we'll see billions and billions more stars.
<v Speaker 3>Billions would be.
<v Speaker 2>Billions, And it's crucial to remember this isn't just about
<v Speaker 2>counting stars like notches on a belt. It's about the
<v Speaker 2>treasure trove of information each one carries. She points out
<v Speaker 2>that the dust data is encoded in every star Roman detects. Right,
<v Speaker 2>So every single star Roman looks at becomes like a
<v Speaker 2>tiny cosmic probe telling us something about the interstellar stuff
<v Speaker 2>its light passed through on the way here.
<v Speaker 3>Yeah, like having billions of tiny flashlights shining through the
<v Speaker 3>fog exactly, each.
<v Speaker 2>One revealing a little bit about the fog. Is a density,
<v Speaker 2>its composition, its properties right along that line of sight.
<v Speaker 2>This isn't just a survey. It's like a galactic census
<v Speaker 2>on an absolutely unimaginable scale. It's going to give us
<v Speaker 2>an unprecedented volume.
<v Speaker 3>Of data and building on that incredible scale, This interstellar medium,
<v Speaker 3>this dust and gas, it does so much more than
<v Speaker 3>just get in our way, right, It's intimately involved in
<v Speaker 3>those fundamental galacticlicycles we mentioned earlier, right, the recycling recycling. Yes,
<v Speaker 3>the ISM fuels star and planet formation. It's not just
<v Speaker 3>passive stuff floating around. It's the active ingredient, the cosmic
<v Speaker 3>clay used to create everything we see. It truly is
<v Speaker 3>the architect of stars and worlds.
<v Speaker 2>So how does that process work starting from the ism.
<v Speaker 3>Well, it generally starts when dense blobs of interstellar medium
<v Speaker 3>form molecular clouds. These are often very cold, very dark
<v Speaker 3>regions where the gas and dust get concentrated enough, dense
<v Speaker 3>enough to start collapsing under their own gravity overcome the
<v Speaker 3>internal pressure pushing outwards.
<v Speaker 2>Okay, so gravity takes over.
<v Speaker 3>Gravity takes over inside these clouds. Even small variations in
<v Speaker 3>density can cause regions to become even denser, and these
<v Speaker 3>denser clumps then gravitationally collapse and kick off the first
<v Speaker 3>stages of star development. Think of it like a cosmic whirlpool,
<v Speaker 3>starting up, spinning faster, pulling in more and more material
<v Speaker 3>as it collapses inward. Eventually the core gets so hot
<v Speaker 3>and dense that nuclear fusion ignites, and boom, you have
<v Speaker 3>a new star.
<v Speaker 2>Wow. And that takes millions of years.
<v Speaker 3>Millions of years. Yeah, it's not quick, but Roman will
<v Speaker 3>give us these amazing snapshots of these stellar nurseries all
<v Speaker 3>across our galaxy, even the ones hidden behind thick dust.
<v Speaker 2>And the cycle doesn't just stop when the star is born, right,
<v Speaker 2>The dust keeps playing.
<v Speaker 3>A role, not at all. Once these young stars ignite,
<v Speaker 3>they're not just passive endpoints. They actively influence their surroundings
<v Speaker 3>and contribute to the ongoing cycle. These young stars eject
<v Speaker 3>hot winds, powerful outflows of particles and radiation, and these
<v Speaker 3>winds can cause surrounding dust to clump into planetary building blocks.
<v Speaker 2>Ah, so the star itself helps build its own planets
<v Speaker 2>in a way.
<v Speaker 3>Yes, it's a crucial link. It shows how cosmic dust
<v Speaker 3>isn't just floating randomly, it's actively participating and building bigger things.
<v Speaker 3>These dust grains, made of silicates carbons, may be coated
<v Speaker 3>in ice. They start colliding and sticking together in the
<v Speaker 3>swirling disk of material around the young star. They grow
<v Speaker 3>from microscopic specks into pebbles, then into kilometer sized planetesimals,
<v Speaker 3>and eventually these can smash together and grow into entire planets.
<v Speaker 3>It's the Grand cosmic assembly line, turning diffuse dust into
<v Speaker 3>solid worlds like ours.
<v Speaker 2>So okay, bringing it back. What does all this mean
<v Speaker 2>for us? For you listening? For us as people living
<v Speaker 2>on Earth, It connects directly to our own cosmic origins,
<v Speaker 2>doesn't it. We hear we're made of stardust all the time,
<v Speaker 2>but this makes it feel much more tangible.
<v Speaker 3>It really does. Josh Peak, an associate astronomer at the
<v Speaker 3>Space Telescope Science Institute, has this really powerful way of
<v Speaker 3>putting it that just it clicks. He says, dust carries
<v Speaker 3>a lot of information about our origins and how everything
<v Speaker 3>came to be. Okay, and then he gives this incredibly
<v Speaker 3>relatable aha moment. Right now, we're basically standing on a
<v Speaker 3>really large dust grain. He says, Earth was built out
<v Speaker 3>of lots and lots of really tiny grains that grew
<v Speaker 3>together into a giant ball.
<v Speaker 2>That's incredible when you think about it like that.
<v Speaker 3>Doesn't it? Just pause on that for a second. Every
<v Speaker 3>single atom in your body, every rock, every ocean on Earth,
<v Speaker 3>its history traces back to these tiny dust grains, grains
<v Speaker 3>which themselves were forged in the hearts of stars that
<v Speaker 3>died long ago. It really does change how you think
<v Speaker 3>about the ground on your feet. It makes you feel
<v Speaker 3>profoundly connected to the cosmos.
<v Speaker 2>Honestly, that gives me chills. Just wow. And Roman's mission
<v Speaker 2>it's going to elaborate on these galactical life cycles even
<v Speaker 2>more by mapping these star factories across the galaxy with
<v Speaker 2>way more detail than before. It's set to identify young
<v Speaker 2>clusters of stars in new distant star forming regions. These
<v Speaker 2>are the busy nurseries where new generations of stars are
<v Speaker 2>being born right now, often hidden behind those thick dust curtains.
<v Speaker 2>Pinpointing these nurseries, understanding exactly where they are and what
<v Speaker 2>the dust around them is like, that helps us understand
<v Speaker 2>where and how the galaxy is actively building new things.
<v Speaker 3>It's like taking a detailed census of all the active
<v Speaker 3>construction zones in our galactic city.
<v Speaker 2>Yeah, that's a good way to think about it.
<v Speaker 3>And crucially, this isn't happening in a vacuum. ROMAN is
<v Speaker 3>very much building on the legacy of previous missions, building
<v Speaker 3>on their foundational work. It will contribute data on star
<v Speaker 3>factories previously identified by missions like NASA's retired Spitzer Space
<v Speaker 3>Telescope AH.
<v Speaker 2>Spitzer a legendary mission.
<v Speaker 3>Absolutely, Spitzer was a real pioneer in infrared astronomy. It
<v Speaker 3>gave us these incredible, though often more limited glimpses into
<v Speaker 3>these dusty star forming regions. Remen will essentially pick up
<v Speaker 3>where Spitzer left off, but provide a much much wider view,
<v Speaker 3>a deeper view, and with more detail across the entire
<v Speaker 3>collect plane.
<v Speaker 2>So it's like Spitzer gave us intriguing close ups of
<v Speaker 2>a few construction sites.
<v Speaker 3>Exactly, and Roman is going to give us the full
<v Speaker 3>wide angle, high definition panorama of all the active developments
<v Speaker 3>happening at once. It shows this beautiful continuity in science,
<v Speaker 3>doesn't it leveraging past discoveries to enable the next big breakthroughs?
<v Speaker 2>It really does. And connecting all this together, Catherine Zucker
<v Speaker 2>emphasizes how vital it is to truly understand the environment
<v Speaker 2>where stars form. She says, if you want to understand
<v Speaker 2>star formation in different environments, you have to understand the
<v Speaker 2>interstellar landscape that seeds. It makes sense, it does, and
<v Speaker 2>Roman will be able to link the three D structure
<v Speaker 2>of the interstellar medium with the three D distribution of
<v Speaker 2>young stars across the galaxy's disc, which means we won't
<v Speaker 2>just see where stars are forming anymore. We'll also understand
<v Speaker 2>the specific properties of the gas and dust right there,
<v Speaker 2>the density, the composition, the motion that allowed those stars
<v Speaker 2>to form in the first place.
<v Speaker 3>It's about seeing the whole ecosystem, isn't it the cause
<v Speaker 3>and the effect laid out in three dimensions? This could
<v Speaker 3>genuinely revolutionize how we understand the way galaxies manage their
<v Speaker 3>star formation over cosmic time.
<v Speaker 2>Okay, so beyond individual stars and where they're born. Romans
<v Speaker 2>insights are also going to help us untangle some of
<v Speaker 2>the Milky Way's really big structural mysteries, particularly the puzzle
<v Speaker 2>of its spiral structure. You know that classic pinwheel like
<v Speaker 2>pattern we see in pictures of other galaxies m hm,
<v Speaker 2>the iconic spirals where stars, gas and dust bunch up
<v Speaker 2>like galactic traffic jams. Our own Milky Way has these
<v Speaker 2>beautiful grand spiral arms, but exactly how they work, where
<v Speaker 2>they came from, what they do, that's still a bit
<v Speaker 2>fuzzy for astronomers.
<v Speaker 3>Indeed, and if we connect this back to the bigger picture,
<v Speaker 3>the overall architecture of the galaxy, Romans new three D
<v Speaker 3>dust maps are going to be absolutely critical. They'll help
<v Speaker 3>refine our understanding of this spiral structure immensely. Right now,
<v Speaker 3>we have general ideas models, but these maps will provide
<v Speaker 3>unprecedented detail about where the dense material the dust is
<v Speaker 3>actually concentrated within those arms, and crucially, how that concentration
<v Speaker 3>relates to where the stars are, where the gas is.
<v Speaker 2>It's like finally getting a clear Hyras satellite view of
<v Speaker 2>a really complex highway system instead of just blurry aerial
<v Speaker 2>photos for miles.
<v Speaker 3>Up exactly, we'll be able to see the specific lanes,
<v Speaker 3>the on ramps, the congestion points of our galactive traffic
<v Speaker 3>much more clearly.
<v Speaker 2>And the actual cause of the spiral structure itself is
<v Speaker 2>still debated, right, That's right.
<v Speaker 3>The precise cause is currently unclear. As the material notes,
<v Speaker 3>there are a few leading theories. One popular idea involves
<v Speaker 3>density waves sweeping through the galactic disc, kind of like
<v Speaker 3>ripples that temporarily compress the gas and dust as they pass.
<v Speaker 2>So not physical waves crashing, but more like traffic jams exactly.
<v Speaker 3>That's a good analogy. It's not like the material itself
<v Speaker 3>is crashing, but more like a persistent traffic jam on
<v Speaker 3>a highway. Individual cars or stars and gas clouds in
<v Speaker 3>this case are constantly moving into and out of the
<v Speaker 3>slow down zone the jam, but the jam itself, that
<v Speaker 3>region of compressed slow down traffic persists and moves along
<v Speaker 3>the galactic disk.
<v Speaker 2>Okay.
<v Speaker 3>Other theories involve things like gravitational nudges from nearby satellite
<v Speaker 3>galaxies or instabilities within the disc itself. Roman will help
<v Speaker 3>figure this out by combining velocity data with dust.
<v Speaker 2>Maps of velocity data how things are moving exactly.
<v Speaker 3>That tells us how the stars and gas are actually
<v Speaker 3>moving within and around the spiral arms. By seeing how
<v Speaker 3>stuff is moving and then correlating that with a detail
<v Speaker 3>three D map of where the dust is thickest, scientists
<v Speaker 3>can compare observations with predictions from models to help identify
<v Speaker 3>the cause, so they can test the theories precisely. They
<v Speaker 3>can rigorously test those competing theories against real high resolution data.
<v Speaker 3>Are the arms relatively stable, long lasting structures or are
<v Speaker 3>they more temporary? Constantly forming and dissolving roman will give
<v Speaker 3>us crucial, maybe even definitive clues.
<v Speaker 2>And the role these spiral arms play in forming stars
<v Speaker 2>is also still debated. It feels like there's a lot
<v Speaker 2>we don't know about our own goals lactic neighborhood.
<v Speaker 3>There really is. It's almost a cosmic chicken and egg question. Yeah.
<v Speaker 3>Some theory suggest that these galactic congestion zones, these traffic
<v Speaker 3>jams where gas and dust pile up, directly trigger star formation.
<v Speaker 3>The compression itself could be the spark that causes gas
<v Speaker 3>clouds to collapse.
<v Speaker 2>Okay, that makes intuitive sense. Squeeze stuff together, it makes stars, right.
<v Speaker 3>But then other theories argue that these traffic jams mainly
<v Speaker 3>just gather material. They act like cosmic conveyor belts or
<v Speaker 3>storage bins, bringing the raw ingredients together, but they don't
<v Speaker 3>necessarily stimulate new starbirth directly. Maybe something else triggers it
<v Speaker 3>once the material is gathered.
<v Speaker 2>There. Ah, Okay, a subtle difference, but important.
<v Speaker 3>It's a subtle but really significant distinction. Yeah, and it
<v Speaker 3>has big implications for how we understand galactic evolution and
<v Speaker 3>how star formation works across the universe.
<v Speaker 2>So how does Roman help settle that debate?
<v Speaker 3>Well, this is where Roman's huge data set becomes absolutely invaluable,
<v Speaker 3>by providing more data on dusty regions across the entire
<v Speaker 3>Milky Way, especially right within the spiral arms themselves. Roman
<v Speaker 3>Wi let scientists compare many galactic environments and study starbirth
<v Speaker 3>and specific structures like the galaxies winding spiral arms or
<v Speaker 3>its central stellar bar.
<v Speaker 2>So they can compare star formation inside an arm versus
<v Speaker 2>just outside it.
<v Speaker 3>Exactly, they can compare rates, look at star formation rates
<v Speaker 3>inside a spiral arm versus just outside it, or in
<v Speaker 3>regions with really dense dust versus less dense regions, and
<v Speaker 3>then compare those observed rates to what the different theories
<v Speaker 3>predict should happen. This kind of comparative analysis across the
<v Speaker 3>entire galactic disc, with a three D view of both
<v Speaker 3>the dust and the young stars, that's something we just
<v Speaker 3>haven't been able to do with this kind of statistical
<v Speaker 3>power before. It offers a real chance to finally answer
<v Speaker 3>these long standing questions about what really drives starbirth in
<v Speaker 3>galaxies like ours.
<v Speaker 2>This whole mission truly represents a legacy, doesn't it, Not
<v Speaker 2>just for the scientists working on it now, but for
<v Speaker 2>well for future generations, for all of us who look
<v Speaker 2>up at the sky. Absolutely, the sheer scale of what
<v Speaker 2>Roman is expected to achieve is just it's almost hard
<v Speaker 2>to grasp. Its Galactic plane survey is planned to map
<v Speaker 2>roughly twenty billion stars.
<v Speaker 3>Twenty billion.
<v Speaker 2>That's about four times more stars than have currently been
<v Speaker 2>mapped by previous surveys like Gaya. It's a staggering leap,
<v Speaker 2>and just mapping our home galaxy.
<v Speaker 3>It really is.
<v Speaker 2>We're talking about an unprecedented data set that's going to
<v Speaker 2>reshape galactic astronomy for decades. It'll offer insights we probably
<v Speaker 2>haven't even thought to look for yet.
<v Speaker 3>Josh Peak really capture the magnitude of this when he said,
<v Speaker 3>with Roman's massive survey of the galactic plane, we'll be
<v Speaker 3>able to have this deep technical understanding of our galaxy.
<v Speaker 3>It's not just a surface level map. It's a deep,
<v Speaker 3>granular understanding its components, how they move, its history, its
<v Speaker 3>future potential. Yeah, and this isn't just data for today's researchers.
<v Speaker 3>It's a foundational data set. It's going to power discoveries
<v Speaker 3>for generations, much like the Hubble deep fields are still
<v Speaker 3>yielding new science decades later.
<v Speaker 2>And what's truly exciting, especially in this day and AGAs,
<v Speaker 2>is how accessible this data will be. It feels like
<v Speaker 2>a real scientific gift to the world. After the initial processing,
<v Speaker 2>Roman's data will be available to the public online, specifically
<v Speaker 2>through the Roman Research Nexus and the Barbara A. Mcculsky
<v Speaker 2>Archive for Space Telescopes or MAAS.
<v Speaker 3>Right MEMENAST already holds data from Hubble tests JWST.
<v Speaker 2>Exactly, and these aren't some obscure, locked down archives. These
<v Speaker 2>platforms will each provide open access to the data for years.
<v Speaker 3>To come, which is huge.
<v Speaker 2>It means anyone professional astrophysicists, curious university students, even dedicated
<v Speaker 2>citizen scientists working from home will be able to dive in, explore,
<v Speaker 2>and analyze this incredible wealth of information. The potential for
<v Speaker 2>discovery by people outside the usual channels is just immense.
<v Speaker 3>That open access really fosters a more collaborative, a more
<v Speaker 3>expansive scientific future. It helps democratize discovery, doesn't it. It really does.
<v Speaker 3>Josh Peak's vision for the future here really sums it
<v Speaker 3>up perfect. He said, people who aren't born yet are
<v Speaker 3>going to be able to do really cool analyses of
<v Speaker 3>this data.
<v Speaker 2>Wow, people who aren't born yet.
<v Speaker 3>Yeah, think about that. It frames Roman's mission as something
<v Speaker 3>much bigger than just an immediate scientific return. He called
<v Speaker 3>it a really beautiful piece of our heritage to hand
<v Speaker 3>down to future generations and to celebrate.
<v Speaker 2>A piece of our heritage.
<v Speaker 3>I like that it's providing the tools, the raw material
<v Speaker 3>for discoveries we can't even imagine right now. It ensures
<v Speaker 3>the legacy of this mission will just keep unfolding and
<v Speaker 3>inspiring for decades, maybe even centuries.
<v Speaker 2>So for everyone listening who's now eagerly anticipating this, when
<v Speaker 2>can we expect Roman to actually launch and start this
<v Speaker 2>incredible journey?
<v Speaker 3>Well, the official plan is for Roman to launch no
<v Speaker 3>later than May twenty twenty seven.
<v Speaker 2>Okay, so within the next few years, yes.
<v Speaker 3>But the team is actually working towards the potential early launch,
<v Speaker 3>possibly as soon as fall twenty.
<v Speaker 2>Twenty six, oh even sooner. That's exciting.
<v Speaker 3>It is so the way, it might not be too
<v Speaker 3>much longer until we start getting these unprecedented insights and
<v Speaker 3>quite literally these new pictures of our home the Milky Way.
<v Speaker 2>Okay, so, just to kind of wrap up everything we've
<v Speaker 2>talked about, the Nancy Grace Roman Space Telescope is really
<v Speaker 2>set to revolutionize how we see and understand the Milky Way.
<v Speaker 2>It's going to do this by peering straight through that
<v Speaker 2>cosmic dust that is hidden so many secrets for so long.
<v Speaker 2>It basically turns an obstacle into an amazing tool. Using
<v Speaker 2>its incredible infrared vision. Roman won't just see through the
<v Speaker 2>interstellar fog. It's going to decode the fog itself its
<v Speaker 2>properties that will let us build the most detailed three
<v Speaker 2>D maps of our galaxy ever created.
<v Speaker 3>Yeah, truly three dimensional.
<v Speaker 2>And these maps promised to unlock fundamental mysteries about how
<v Speaker 2>stars and planets form, shining a light on our own
<v Speaker 2>cosmic origins, and they'll help us finally figure out the
<v Speaker 2>causes and the rolls of the Milky Way's beautiful but
<v Speaker 2>still mysterious spiral.
<v Speaker 3>Arms, which really raises a final thought, maybe for you
<v Speaker 3>listening as we gather all this unpreditented data about our
<v Speaker 3>galaxies structure, its origins, As we push the boundaries of
<v Speaker 3>what we can see and comprehend, how might our own
<v Speaker 3>understanding of humanity's place in this vast cosmos continue to
<v Speaker 3>shift and Expand that's a big question, it is because
<v Speaker 3>it's not just about distant stars and dust clouds, is it.
<v Speaker 3>It's fundamentally about our story, our origins written in the
<v Speaker 3>very fabric of the universe, and how deeply connected we
<v Speaker 3>are to all of it.
<v Speaker 2>Absolutely, so, the next time you look up at that
<v Speaker 2>shimmering band of light we call the Milky Way, just
<v Speaker 2>remember it isn't only a collection of faraway stars. It's
<v Speaker 2>this vast, dynamic living system where cosmic dust, the seemingly
<v Speaker 2>simple stuff, holds the keys to understanding our past, our present,
<v Speaker 2>and maybe even our future. What incredible new views will
<v Speaker 2>Roaman unlock for us, and how will those revelations change
<v Speaker 2>the way we see ourselves within this magnificent cosmic dance.
<v Speaker 3>Only time and that penetrating gaze of infrared light will
<v Speaker 3>really tell the sea moss Puss