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: So imagine you are looking up at the night sky,
Speaker 2: You're just taking in all those stars, and you suddenly
Speaker 2: realize that for decades, astronomers have been staring directly at
Speaker 2: a massive, completely missing piece of a cosmic puzzle.
Speaker 3: Right, it's a massive blind spot. We've essentially been trying
Speaker 3: to understand the deep ocean by you only looking at
Speaker 3: the bioluminescent algae glowing on the surface.
Speaker 2: Exactly and just completely ignoring the water itself. Which sounds absurd,
Speaker 2: but that is basically what we've been doing when we
Speaker 2: look back at the early universe.
Speaker 3: Yeah, we have. I've always known the early universe had
Speaker 3: to be absolutely saturated with hydrogen gas. I mean, it's
Speaker 3: the fundamental building block.
Speaker 2: Of everything, right, It's what makes up the stars, which
Speaker 2: then forged the heavier elements that make planets and well.
Speaker 3: Us exactly, but actually finding that foundational hydrogen out there
Speaker 3: in the deep dark that has been honestly one of
Speaker 3: the most frustrating optical illusions in modern astrophysics.
Speaker 2: And that's exactly what we're getting into today. We're traveling
Speaker 2: back roughly eleven point three billion years to uncover how
Speaker 2: a really revolutionary telescope project finally illuminated the dark.
Speaker 3: Yeah, and they didn't just find a little bit of
Speaker 3: this missing gas either.
Speaker 2: No, not at all. They revealed tens of thousands of
Speaker 2: these gigantic, glowing clouds of hydrogen structures that are rewriting
Speaker 2: our whole understanding of how the cosmos grew up.
Speaker 3: It really is a complete paradigm shift because seeing this
Speaker 3: invisible stuff, it doesn't just require looking harder at the.
Speaker 2: Sky, right. You can't just stare longer, exactly.
Speaker 3: You have to look fundamentally differently. It requires a total
Speaker 3: shift in how we capture and process the light of
Speaker 3: the universe.
Speaker 2: But to really get why finding this hydrogen is such
Speaker 2: a monumental breakthrough, I think we first need to understand
Speaker 2: why everyone was so desperately looking for it to begin with.
Speaker 3: That's a good point we have to go back to
Speaker 3: a very specific, incredibly chaotic era in the universe's timeline.
Speaker 2: Right, the era cosmologists call cosmic.
Speaker 3: Noon, Yeah, cosmic noun. So if we want to understand
Speaker 3: the universe we live in today, like our mature, relatively
Speaker 3: quiet Milky Way, we have to look back to those formative.
Speaker 2: Years, the wild teenage years of the universe.
Speaker 3: Exactly. We are talking about a period roughly ten billion
Speaker 3: to twelve billion years ago in astronomical terms, that corresponds
Speaker 3: to a redshift of about two to three Okay.
Speaker 2: And why cosmic noon specifically.
Speaker 3: Because this was the absolute peak of the universe's star
Speaker 3: forming day. The universe was only about two to three
Speaker 3: billion years.
Speaker 2: Old at that point, so still pretty young.
Speaker 3: Very young. And this was the era when galaxies were rowing,
Speaker 3: merging and forming stars at their absolute fastest rates.
Speaker 2: To give some context for that, our Milky Way currently
Speaker 2: forms about one solar mass, so one sun's worth of
Speaker 2: new stars per year.
Speaker 3: Right, It's pretty sedate now, But during cosmic Noon, some
Speaker 3: of these early starburst galaxies were churning out hundreds, even
Speaker 3: thousands of solar masses per year.
Speaker 2: Thousands a year.
Speaker 3: Yeah, it was an epoch of just explosive, unparalleled cosmic construction.
Speaker 2: Just pause and think about that scale for a second.
Speaker 2: The light from those galaxies has been traveling through the
Speaker 2: vacuum of space for over eleven billion years just to
Speaker 2: reach our telescopes.
Speaker 3: It's ancient history playing out right in front of us.
Speaker 3: We are seeing these systems in their absolute prime.
Speaker 2: But here is the crux of the whole problem. Right,
Speaker 2: Galaxies don't just magically expand out of nowhere.
Speaker 3: No, they definitely do not. Star formation requires fuel, Right.
Speaker 2: A galaxy doesn't just decide to double its size and
Speaker 2: spawn a thousand new stars out of empty space.
Speaker 3: Exactly. It requires massive, really dense molecular clouds to gravitationally collapse,
Speaker 3: and the raw building block for those clouds is hydrogen gas.
Speaker 2: So to sustain that kind of insane explosive growth across
Speaker 2: the universe, there had to be vast reservoirs of hydrogen feeding.
Speaker 3: Them, vast easily accessible oceanic reservoirs. Because if a galaxy
Speaker 3: is churning out one thousand stars a year, it is
Speaker 3: burning through its internal gas reserves incredibly.
Speaker 2: Fast, like a cosmic teenage growth spurt.
Speaker 3: That is the perfect analogy.
Speaker 2: Right, because if you have a teenager growing that fast,
Speaker 2: they're constantly emptying the refrigerator. They need thousands of calories
Speaker 2: a day just to maintain it.
Speaker 3: Exactly without a constant influx of fresh gas from the
Speaker 3: surrounding environment, those galaxies would just.
Speaker 2: Quench quench, meaning they just burn out.
Speaker 3: Yeah, they would run out of fuel and stop forming
Speaker 3: stars entirely in a matter of a few tens of
Speaker 3: millions of years, which is just a blink of an
Speaker 3: eye in cosmic terms.
Speaker 2: So, if we knew these early galaxies were growing at
Speaker 2: record breaking speeds, and we knew they had to be
Speaker 2: pulling in unfathomable amounts of hydrogen to feed that growth,
Speaker 2: how could we possibly misplace the refrigerators?
Speaker 3: That's the billion dollar question. How do you lose something
Speaker 3: that massive?
Speaker 2: Right Where was all the hydrogen?
Speaker 3: Well, the answer lies in the deeply frustrating physics of
Speaker 3: neutral hydrogen itself. It's not that we misplace the gas.
Speaker 3: They're siding completely dark. To our standard methods of observation,
Speaker 3: hydrogen gas in the early universe, especially in the vast
Speaker 3: spaces between galaxies, the intercalactic medium is mostly cold.
Speaker 2: And neutral, meaning it doesn't generate its own visible light, right.
Speaker 3: It just sits there, invisible against the black background of space.
Speaker 3: To actually see it, you need a very specific physical
Speaker 3: interaction with an intense energy source.
Speaker 2: It essentially needs to be eliminated by the galaxy it's surrounding, exactly.
Speaker 3: But it's not simply reflecting light like a mirror. It's
Speaker 3: a quantum physical process.
Speaker 2: Okay, let's break that down.
Speaker 3: So it requires a galaxy packed full of massive, young
Speaker 3: hot stars that are just blasting out extreme ultraviolet radiation debeators. Right.
Speaker 3: When those highly energetic UV photons hit the cold, neutral
Speaker 3: hydrogen gas surrounding the galaxy, they interact with the hydrogen atoms.
Speaker 2: And the hydrogen atoms is one proton and one electron, right, very.
Speaker 3: Simple, very simple. So the UV photon transfers its energy
Speaker 3: to that single electron, bumping it up to a higher
Speaker 3: energy state.
Speaker 2: It gets excited exactly, but.
Speaker 3: It can't stay in that excited state forever. When the
Speaker 3: electron inevitably drops back down to its original ground state,
Speaker 3: it releases that stored.
Speaker 2: Energy, and that release is what we can actually see.
Speaker 3: Yes, it emits a photon at a very specific, highly
Speaker 3: precise wavelength down to the decimal one hundred and twenty
Speaker 3: one point six nanometers one.
Speaker 2: Hundred and twenty one point six nanometers, and that specific
Speaker 2: wavelength is what astronomers are always hunting for.
Speaker 3: Precisely in astrophysics, this emission is known as the Liman.
Speaker 2: Alpha line Limon alpha. Okay.
Speaker 3: And when you have an entire massive cloud of hydrogen
Speaker 3: doing this all at once, absorbing UV light and re
Speaker 3: emitting it at one hundred and twenty one point six nanimeters,
Speaker 3: the entire cloud begins to glow.
Speaker 2: Which creates what astronomers call Liman alpha nebulae exactly. Okay,
Speaker 2: so let me try and synthesize this. It sounds like
Speaker 2: an invisible ink scenario, but you know, playing out in
Speaker 2: three dimensions on a cosmic scale.
Speaker 3: I like that invisible ink.
Speaker 2: The neutral hydrogen gas is the invisible ink, permeated all
Speaker 2: throughout the early universe. It's everywhere but completely undetectable until
Speaker 2: someone shines a specific UV black light on it.
Speaker 3: Right. The hyperactive Young galaxy is the black light, and that.
Speaker 2: Activates the ink, causing it to glow at that Liman
Speaker 2: alpha wavelength.
Speaker 3: That's a great starting point, but it's actually even more
Speaker 3: chaotic than just shining a black light on a page.
Speaker 2: Oh, how so.
Speaker 3: Because when that liman alpha photon is emitted by the
Speaker 3: relaxing electron, it doesn't just travel in a nice straight
Speaker 3: line toward our telescopes. Why not, Because the surrounding cloud
Speaker 3: is made of the exact same hydrogen atoms, So that
Speaker 3: newly emitted photon almost immediately hits another hydrogen atom, excites
Speaker 3: it and gets re emitted in a totally random direction. Wow,
Speaker 3: And then it hits another one and another. It's a
Speaker 3: process called resonance scattering.
Speaker 2: So it's bouncing around them like.
Speaker 3: A pinball in a machine. It can bounce around inside
Speaker 3: that massive gas cloud for thousands of years, just trapped
Speaker 3: in the fog. Exactly. By the time the photon finally
Speaker 3: escapes the outer edge of the cloud and begins it's
Speaker 3: eleven billion year journey toward Earth, the light has been
Speaker 3: completely diffused, which explains.
Speaker 2: Why these structures don't look like sharp, crisp rings of light.
Speaker 2: They look like massive, blurry, glowing halos, the morphous halos. Yes, okay,
Speaker 2: that pinball effect makes perfect sense. But wait, I have
Speaker 2: to push back on the historical timeline here for a second. Sure,
Speaker 2: if we have understood the quantum mechanics of this Linman
Speaker 2: alpha line for decades, and we knew about these glowing halos.
Speaker 2: Why did it take until now to map them out?
Speaker 3: That is the big question.
Speaker 2: I mean, we have the James web Space Telescope sitting
Speaker 2: out there right now. It is the most sensitive advanced
Speaker 2: optical technology humanity has ever built. Why couldn't JWST just
Speaker 2: sweep the sky and find all of this invisible ink?
Speaker 3: Because of a fundamental trade off in astronomical optics. It's
Speaker 3: the battle of depth versus.
Speaker 2: Breadth, depth versus breath. Okay, explain that.
Speaker 3: You're absolutely right that JWST is phenomenal. Its sensitivity is unmatched.
Speaker 3: But JWST is essentially a hyper powered microscope.
Speaker 2: So its field of view is tiny.
Speaker 3: Incredibly tiny. The actual chunk of the sky it can
Speaker 3: see at any given moment is minuscule. If you wanted
Speaker 3: to map a statistically significant portion of the early universe
Speaker 3: using JOUST, it would take millennia of continuous observation.
Speaker 2: Time millenniaow, So it's just not practical for sweeping surveys.
Speaker 3: Not at all. JWST is designed to stare deeply at individual,
Speaker 3: pre selected targets it's not meant to blindly survey massive
Speaker 3: swaths of empty space.
Speaker 2: So JWST is like taking a macro lens close up
Speaker 2: of a single pour on someone's skin. You get amazing detail,
Speaker 2: but you completely miss the rest of the face, let
Speaker 2: alone the room they are standing in.
Speaker 3: That's spot on, and previous astronomical surveys were trapped by
Speaker 3: this dual problem.
Speaker 2: What do you mean by dual problem?
Speaker 3: Well, on one hand, older wider field instruments simply lacked
Speaker 3: the sensitivity to pick up the incredibly faint liman alpha emissions.
Speaker 2: So they were looking wide, but they couldn't see the
Speaker 2: dim stuff right.
Speaker 3: They could only catch the absolute brightest, most extreme outlier
Speaker 3: examples of these halos, usually the ones illuminated by hyper
Speaker 3: luminous quasars.
Speaker 2: And they missed the normal stuff entirely exactly.
Speaker 3: And on the other hand, highly sensitive telescopes like Hubble
Speaker 3: and now JWST were so zoomed in on the central
Speaker 3: galaxies themselves that they inadvertently cropped out the surrounding environment.
Speaker 2: Oh, they were staring so intensely at the uv black
Speaker 2: light that they missed the ink spreading out into the
Speaker 2: dark around it.
Speaker 3: Precisely the vast middle ground. The normal, everyday hydrogen halos
Speaker 3: that surrounded the majority of typical galaxies during cosmic noon
Speaker 3: remain entirely hidden, so they were.
Speaker 2: Either two zoomed in or just not sensitive enough.
Speaker 3: Right. To solve the problem of missing that middle ground,
Speaker 3: astronomers realized they couldn't just build a bigger, conventional telescope.
Speaker 2: They needed a totally different kind of tool.
Speaker 3: They needed an instrument that could simultaneously look at massive
Speaker 3: areas of the sky while also dissecting the light with
Speaker 3: enough precision to pick out that exact one hundred and
Speaker 3: twenty one point six ninimeter Lineman alpha wavelength.
Speaker 2: Against all the noisy background of space.
Speaker 3: No less exactly, And that crazy engineering requirement is what
Speaker 3: birthed the instrument we're talking about today, eighth eight decads.
Speaker 2: Located at the McDonald Observatory in West Texas.
Speaker 3: Right, the Hobby Eberly Telescope Dark Energy Experiment.
Speaker 2: Let's unpack eh dicks because the name itself is super interesting.
Speaker 2: It's the dark energy Experiment. But we are talking about
Speaker 2: revolutionizing our map of hydrogen gas. Right. How did a
Speaker 2: project build to study dark energy end up solving the
Speaker 2: mystery of the universe's missing hydrogen refrigerators.
Speaker 3: It's one of those great stories of scientific cross pollination.
Speaker 3: The primary goal of HX really was to study dark energy.
Speaker 2: That mysterious force accelerating the expansion of the universe.
Speaker 3: Exactly, to measure the effects of dark energy over time,
Speaker 3: cosmologists need to map the precise three D positions of
Speaker 3: millions of distant objects. They need to see how the
Speaker 3: fabric of space has stretched.
Speaker 2: So they need a reliable marker to map the grid.
Speaker 3: Yes, a tracer, and the most abundant reliable tracers at
Speaker 3: that specific distance eleven billion light years away are galaxies
Speaker 3: that emit strongly in the Liman alpha line.
Speaker 2: Ah, so the Liman alpha emitters yes laees.
Speaker 3: To build a map of dark energy, they first had
Speaker 3: to build a map of these hydrogen glowing galaxies.
Speaker 2: The hydrogen was just the ink they were using to
Speaker 2: draw the grid lines of the universe's.
Speaker 3: Expansion, That's exactly it. But to build that map, they
Speaker 3: had to engineer an instrument with capabilities that are genuinely staggering.
Speaker 2: Because hate X isn't just snapping pretty pig the sky right, No.
Speaker 3: Not at all. It is actively capturing and analyzing the
Speaker 3: spectra of over one million galaxies.
Speaker 2: A million galaxies. That's insane, it.
Speaker 3: Really is, and the way it does this is a
Speaker 3: marvel of modern engineering. They equipped the telescope with an
Speaker 3: instrument called.
Speaker 2: VIRUS VIRUS, which stands for the Visible Integral Field Replicable
Speaker 2: Unit Spectrograph. Astrotomers really do have a unique talent for
Speaker 2: forcing acronyms, don't they.
Speaker 3: Oh, they absolutely do. It's practically a requirement in astrophysics.
Speaker 3: But the technology behind VIRUS is incredible.
Speaker 2: How does it actually work.
Speaker 3: It consists of over one hundred and fifty individual spectrographs.
Speaker 3: When the telescope points at a patch of sky, it
Speaker 3: doesn't just take one measurement. It utilizes an array of
Speaker 3: thirty five thousand optical fibers. Thirty five thousand, yes, think
Speaker 3: of them as tiny, highly precise light pipes. Each fiber
Speaker 3: captures the light from a tiny specific point in the
Speaker 3: sky and feeds it into the spectrograph.
Speaker 2: A spectrograph acts kind of like a.
Speaker 3: Prism, exactly like a highly advanced prism. It takes the
Speaker 3: incoming light and stretches it out into its constituent wavelengths,
Speaker 3: creating a spectrum.
Speaker 2: So they can look at that spectrum and hunt for
Speaker 2: that exact spike in intensity at the Liman alpha wavelength exactly.
Speaker 3: But there's a catch. Because the universe is expanding, that
Speaker 3: one hundred and twenty one point six nanimeter light gets
Speaker 3: stretched out as it travels to.
Speaker 2: Us the cosmological redshift.
Speaker 3: Right by the time that ultraviolet photon reaches West Texas
Speaker 3: eleven billion years later, it has been stretched all the
Speaker 3: way into the visible blue or green part of the spectrum.
Speaker 2: So by measuring exactly how much the light has been
Speaker 2: stretched into the blue or green htdd X can determine
Speaker 2: exactly how far away the gas is Precisely.
Speaker 3: It gives them the three D position of the gas cloud,
Speaker 3: not just a two D coordinate.
Speaker 2: So instead of just taking a flat photograph, they are
Speaker 2: taking a deep three D core sample of the universe. Yes,
Speaker 2: but the scale of what they're doing is what truly
Speaker 2: blows my mind. The researchers noted that the footprint of
Speaker 2: this observation area covers a region of the sky measuring
Speaker 2: over two thousand and full moons.
Speaker 3: It's massive.
Speaker 2: Just think about that. When you look at the moon,
Speaker 2: it takes up a tiny fraction of a degree in
Speaker 2: the sky. Imagine painting two thousand of them across the dark.
Speaker 3: Right, It's unparalleled coverage.
Speaker 2: This isn't just moving from looking through a straw to
Speaker 2: opening at bay window. This is knocking down the entire
Speaker 2: wall of the observatory.
Speaker 3: And because of that massive footprint, combined with those thirty
Speaker 3: five thousand optical fibers, h et Dex produces one hundred
Speaker 3: thousand distinct spectra in a single observation, one hundred thousand
Speaker 3: in a single shot. The raw data generation is mind boggling.
Speaker 3: Over the course of the survey, we are talking about
Speaker 3: capturing nearly half a petabite of raw observational data.
Speaker 2: Half a petabite, so a petabyte is a thousand terabytes, right.
Speaker 3: Imagine a massive data center full of the largest commercial
Speaker 3: hard drives available, completely filled with nothing but raw light frequencies.
Speaker 2: Processing that much data has to require a massive leap
Speaker 2: in computational power. I mean, you can't just have a
Speaker 2: team of grad students eyeballing a million spectra looking for
Speaker 2: a little Linman alpha spike.
Speaker 3: No, absolutely not. It's not just finding a needle in
Speaker 3: a haystack. It's like programming a system to sort through
Speaker 3: a million haystacks and identify only the specific needles that
Speaker 3: are vibrating at one exact frequency.
Speaker 2: So how did they do it?
Speaker 3: Well, The astronomical data pipeline is just as important as
Speaker 3: the telescope itself. To sift through that half a petabyte
Speaker 3: of data, the HPDX team utilized massive supercomputers.
Speaker 2: At the Texas Advanced Computing Center, right.
Speaker 3: Yeah, Specifically they're Fronterra and Stampede systems. They had to
Speaker 3: design highly sophisticated algorithms that could automatically clean the data.
Speaker 2: Cleaned it how.
Speaker 3: By subtracting the noise of our own atmosphere, filtering out
Speaker 3: closer foreground galaxies that were contaminating the image, basically isolating
Speaker 3: only the distant early galaxies.
Speaker 2: So, out of the one point six million early galaxies
Speaker 2: they eventually identified in the overall data, how many did
Speaker 2: they focus on for this specific breakthrough?
Speaker 3: The supercomputers filtered that down to focus on the seventy
Speaker 3: thousand brightest ones.
Speaker 2: Okay, so the bay window is open, the thirty five
Speaker 2: thousand optical fibers are pulling down the light, and the
Speaker 2: supercomputers are crunching the spectra of these seventy thousand prime targets, right,
Speaker 2: What exactly did they see swimming out there in the
Speaker 2: cosmic ocean. When they finally looked closely at the empty
Speaker 2: spaces between the galaxies, they.
Speaker 3: Saw the physical manifestation of the universe's fuel lines. They
Speaker 3: found the massive hydrogen halos that had been hiding in
Speaker 3: planes sight this whole time.
Speaker 2: What did that actually look like in the data?
Speaker 3: The supercomputers were specifically trained to look for a distinct
Speaker 3: structural signature, a highly compact central region of intensely glowing hydrogen,
Speaker 3: which is the galaxy itself, okay, and that central region
Speaker 3: is completely surrounded by a thinner, much more expansive, diffuse
Speaker 3: cloud of lime and alpha mission extending far out into
Speaker 3: the deep space around it and out.
Speaker 2: Of the seventy thousand galaxies, they looked at how many
Speaker 2: had this signature.
Speaker 3: Nearly half of them showed clear, indisputable evidence of this
Speaker 3: surrounding hydrogen halo.
Speaker 2: Nearly half. That is a staggering hit rate, it really is.
Speaker 2: It basically means that if you randomly pointed at a
Speaker 2: bright galaxy during cosmic noon, there was a coin flip
Speaker 2: chance that was surrounded by this massive, invisible reservoir exactly.
Speaker 2: We really need to contextualize the physical characteristics of these
Speaker 2: structures because the numbers are hard to wrap the human
Speaker 2: brain around. Just how big are these hydrogen halos.
Speaker 3: They are immense. The newly revealed halos range in size
Speaker 3: from tens of thousands to hundreds of thousands of light
Speaker 3: years across.
Speaker 2: Just from some local perspective, here, our entire Milky Way galaxy,
Speaker 2: which contains hundreds of billions of stars, massive black holes,
Speaker 2: vast stellar nurseries, all of that is roughly one hundred
Speaker 2: thousand light years across.
Speaker 3: Right.
Speaker 2: It takes light, the fastest thing in the universe, a
Speaker 2: hundred millennia, just to cross from one edge of our
Speaker 2: galaxy to the other. And you're saying, some of these
Speaker 2: single gas clouds are significantly larger than our entire galaxy.
Speaker 3: Easily larger. But it's not just their sheer size that
Speaker 3: is so groundbreaking, it is their structure. What do you
Speaker 3: mean when we picture cosmic phenomena, we are super biased
Speaker 3: by our local solar system. We tend to picture clean,
Speaker 3: symmetrical spheres like planets or stars, or even the neat
Speaker 3: spiral arms of a mature galaxy, nice and tidy, right,
Speaker 3: but the structures they found at cosmic noon were completely
Speaker 3: asymmetrical and chaotic, messy, very messy. Some of the clouds
Speaker 3: surrounding isolated single galaxies were relatively simple shaped, somewhat like
Speaker 3: giant cosmic footballs.
Speaker 2: Okay, footballs, I can picture.
Speaker 3: But the truly fascinating discoveries were the halos surrounding groups
Speaker 3: of multiple galaxies.
Speaker 2: Right, the sprawling, irregular blobs. I love how the researchers
Speaker 2: literally describe them as giant amobas with tendrils extending into space.
Speaker 2: It's a great visual it is. But when an astrophysicist
Speaker 2: abandons neat geometric classifications and resorts to biological terms like amoeba,
Speaker 2: you know they're looking at something inherently messy. Oh absolutely,
Speaker 2: What is the physical mechanism eating these tendrils? I mean,
Speaker 2: why don't they just form a massive neat sphere of
Speaker 2: gas under their own gravity.
Speaker 3: Because what we are looking at is a highly volatile
Speaker 3: region known as the circungalactic medium or the CGM.
Speaker 2: CGM yeah, space just outside the galaxy, right.
Speaker 3: It is the dynamic battleground between the galaxy and the cosmos.
Speaker 3: Those tendrils are actually the physical manifestation of the cosmic
Speaker 3: web itself. How so, well, the universe isn't just a
Speaker 3: uniform soup of matter. Dark matter clumps together into massive filaments,
Speaker 3: creating this huge web like structure across the universe.
Speaker 2: Okay, and the galaxy sit at the intersections of that web.
Speaker 3: Exactly, These dark matter filaments exert immense gravitational pull, funneling
Speaker 3: massive streams of cold, pristine hydrogen gas directly into the
Speaker 3: gravitational well of the galaxy.
Speaker 2: So the tendrils reaching outward, those are the actual fuel
Speaker 2: lines pulling the gas in. Yes, the teenagers relentlessly mpying
Speaker 2: the refrigerator.
Speaker 3: Exactly, that's the cold gas flowing in. But remember it
Speaker 3: is a two way street.
Speaker 2: Because the galaxy is also doing something right.
Speaker 3: Because the galaxy is pulling all this gas and frantically
Speaker 3: forming stars at a rate of hundreds of solar masses
Speaker 3: a year, it is also experiencing massive.
Speaker 2: Violent feedback back from the stars.
Speaker 3: From the supernovae. When those massive young stars die, they explode.
Speaker 3: Thousands of supernovae exploding simultaneously create immense galactic winds. These
Speaker 3: winds blast superheated gas, radiation and newly forged heavy elements
Speaker 3: back out of the galaxy and millions of miles per hour.
Speaker 2: And that outward blast slams into the incoming cold gas
Speaker 2: stream precisely.
Speaker 3: It's an incredibly violent traffic jam that is wild.
Speaker 2: You have gravity mercilessly pulling cold gas in along the
Speaker 2: dark matter filaments, while explosive supernova feedback is aggressively blasting
Speaker 2: hot gas back out.
Speaker 3: It is a messy, turbulent feeding frenzy and the shockfronts,
Speaker 3: the interplay between the inflows and outflows, that is what
Speaker 3: creates these sprawling, amorphous amoeba like shapes.
Speaker 2: So they aren't just static clouds. They are highly complex,
Speaker 2: multi phase environment, very much so.
Speaker 3: And the fact that we can now trace the shape
Speaker 3: of these amibas gives us direct visual evidence of how
Speaker 3: galaxies breathe.
Speaker 2: How they inhale fuel and exhale the byproducts of stellar
Speaker 2: evolution exactly. And just to keep the scale anchored for you,
Speaker 2: a single wiggling tendril on one of these giant space
Speaker 2: ambas could easily dwarf our entire Milky Way galaxy.
Speaker 3: It's almost incomprehensible.
Speaker 2: We're talking about structures so unimaginably large they defy human comprehension,
Speaker 2: just churning away in the dark of cosmic noons. Yeah,
Speaker 2: but you know, finding a few of these massive space
Speaker 2: amvas would just be a neat curiosity fun anomenally for
Speaker 2: a textbook, right, But finding a massive, sprawling population of
Speaker 2: them that completely alters our statistical understanding of the universe's mechanics.
Speaker 3: And that is the ultimate breakthrough of the hate TECH study.
Speaker 3: It isn't just the discovery of the halos themselves, it
Speaker 3: is the sheer, overwhelming volume.
Speaker 2: The data put that into perspective for us. How many
Speaker 2: of these did we know about before this?
Speaker 3: Well, prior to this release, our entire known catalog of
Speaker 3: these massive hydrogen halos, built up painstakingly over twenty years
Speaker 3: of targeted observations, was roughly three thousand.
Speaker 2: Okay three thousand, and After HATESECH, thanks.
Speaker 3: To the massive blind sweep of the survey, that number
Speaker 3: jumped to over thirty three thousand.
Speaker 2: A tenfold increase overnight overnight. That is the kind of
Speaker 2: statistical leap that fundamentally changes a whole scientific field.
Speaker 3: It is absolutely crucial because a leap of that magnitude
Speaker 3: proves definitively that these halos are not rare anomalies.
Speaker 2: They aren't just weird cosmic curiosities that only happen under
Speaker 2: freak conditions.
Speaker 3: Right. They aren't just forming near hyper luminous quasars. They
Speaker 3: are a fundamental standard feature of the early universe.
Speaker 2: So if you were a normal star forming galaxy growing
Speaker 2: up during cosmic noon, you almost certainly had one of
Speaker 2: these massive glowing hydrogen amibas surrounding you.
Speaker 3: It was the default state of galactic evolution. But what
Speaker 3: is even more staggering is that the researchers readily admit
Speaker 3: that thirty three thousand is a severe underestimate of the
Speaker 3: true population.
Speaker 2: Wait, how so if the supercomputers just found thirty thousand
Speaker 2: new ones in the data, how could they still be
Speaker 2: missing a significant portion of them?
Speaker 3: Because we are still limited by the physics of the invisible.
Speaker 2: Ink ah the black light effect. Right.
Speaker 3: Remember, the hydrogen only glows when it is hit by
Speaker 3: enough ultraviolet radiation from the central galaxy.
Speaker 2: So what happens with the fainter galaxies.
Speaker 3: The faintest systems in the survey, the ones that are
Speaker 3: forming stars but maybe not at the extreme frantic rates
Speaker 3: of the brightest ones. They simply aren't producing quite enough
Speaker 3: blinding UV light to fully illuminate the massive halo surrounding them.
Speaker 2: So the central galaxy is acting as a black light,
Speaker 2: but the bulb just isn't strong enough to light up
Speaker 2: the outer edges of.
Speaker 3: The room exactly. The gas is physically there, continuing to
Speaker 3: feed the galaxy, but the resonant scattering of the liman
Speaker 3: alpha photons drops below the detection threshold of instruments.
Speaker 2: So even with thirty three thousand confirm there's a massive
Speaker 2: population of halos out there where we are only seeing
Speaker 2: the very core, missing the sprawling tendrils entirely, without a doubt.
Speaker 2: It is such a brilliant example of the scientific method
Speaker 2: in action, and it completely shifts the burden over to
Speaker 2: the theoretical side of astrophysics, doesn't it.
Speaker 3: Oh completely?
Speaker 2: I mean, for years, cosmologists have been running these incredibly
Speaker 2: complex supercomputer simulations of how the universe evolved. They built
Speaker 2: these models for cosmic noon based on the physics they understood.
Speaker 3: But they admittedly had massive gaps and holes.
Speaker 2: Because they were forced to base their assumptions on a
Speaker 2: highly biased sample of just three thousand extreme exceptionally bright outliers.
Speaker 3: Right, and now suddenly they have a robust catalog of
Speaker 3: thirty three thousand normal representative examples.
Speaker 2: The problem has entirely shifted from the agony of finding
Speaker 2: these structures to the overwhelming paralysis of processing them. Is
Speaker 2: it terrifying for a theoretical astrophysicist to wake up, look
Speaker 2: this massive data dump from a DEX and realize they
Speaker 2: might have to essentially scrap or radically alter their old
Speaker 2: models and start all over again.
Speaker 3: Honestly, far from terrifying. It is absolutely thrilling. Really, oh yeah,
Speaker 3: this is the moment every scientist hopes for. The apprehension
Speaker 3: of finding out your old model was incomplete is immediately
Speaker 3: replaced by the excitement of having a clear, highly detailed
Speaker 3: map of reality to replace it with.
Speaker 2: I guess that makes sense.
Speaker 3: The old models had gaps because theorists were forced to
Speaker 3: extrapolate what the vast middle ground look like based purely
Speaker 3: on the extremes.
Speaker 2: Like trying to understand human biology by only studying Olympic weightlifters.
Speaker 3: That's a perfect way to put it. Now, the ATDEX
Speaker 3: catalog provides a massive representative sample of general population. This
Speaker 3: is basically the holy grail for cosmologists.
Speaker 2: Because they can finally run real statistical analysis. They aren't
Speaker 2: guessing anymore.
Speaker 3: Exactly. With thirty three thousand distinct data points, astronomers can
Speaker 3: utilize advanced statistical techniques like cross correlation.
Speaker 2: Functions, and what do they let them do?
Speaker 3: They can mathematically analyze how these halos cluster together. They
Speaker 3: can map out exactly how the dark matter must be
Speaker 3: distributed to hold these massive gas clouds together against the
Speaker 3: explosive outflow of the supernovae.
Speaker 2: They can study the actual physics, the real world movement
Speaker 2: of the gas yes.
Speaker 3: And track the evolutionary life cycles of these structures in
Speaker 3: granular detail. They can finally see how a simple football
Speaker 3: shaped halo surrounding an isolated galaxy eventually evolves, merges, and
Speaker 3: warps into a massive multi galaxy amba over millions of years.
Speaker 2: They finally have the hard numbers to ground their simulations
Speaker 2: in actual observation.
Speaker 3: It's game changing.
Speaker 2: It really is an epic journey of scientific discovery. I mean,
Speaker 2: we started at a point where the universe's primary hydrogen reservoirs,
Speaker 2: the very cosmic fuel that built the stars, that eventually
Speaker 2: forge the carbon and oxygen that make up our bodies,
Speaker 2: were just a theoretical.
Speaker 3: Necessity right a mathematical assumption.
Speaker 2: We logically knew the early galaxies had to be consuming
Speaker 2: massive amounts of gas, but the reservoirs themselves were completely
Speaker 2: hidden in the dark, invisible to our standard telescopes, and we.
Speaker 3: Had to rethink our entire approach to find them exactly.
Speaker 2: And that shift in thinking led us to the chaotic,
Speaker 2: explosive era of cosmic Noon, where massive tendrilled space samibas
Speaker 2: fueled the rapid, violent growth of the earliest galaxies. It's
Speaker 2: quid a picture, and finally, all of this hidden architecture
Speaker 2: was brought into the light, not by building a bigger
Speaker 2: conventional lens, but by the sheer, brute force data crunching
Speaker 2: power of heat decks.
Speaker 3: That's the real hero here.
Speaker 2: Deploying thirty five thousand optical fibers across a massive swathe
Speaker 2: of the Texas Knight Sky, capturing half a petabite of
Speaker 2: light spectra, and utilizing supercomputers to filter out the noise,
Speaker 2: we finally saw the universe as it truly was.
Speaker 3: It serves as a powerful reminder of how observational bias
Speaker 3: shapes our understanding of reality. How so well for centuries,
Speaker 3: astronomy has been defined by looking closely at the bright,
Speaker 3: shiny localized objects, the star, the planet's, the dense galactic core.
Speaker 2: The things that are easy to see exactly.
Speaker 3: But this project demonstrates that sometimes the most profoundly important discoveries,
Speaker 3: the structures that actually dictate how the universe evolves, are
Speaker 3: found by having the technological capability and the scientific vision
Speaker 3: to look closely at the supposedly empty dark spaces in between.
Speaker 2: Wow, and that leaves us with a truly incredible lingering
Speaker 2: thought to chew on. Yeah, think about this the next
Speaker 2: time you were standing outside looking up at the stars
Speaker 2: on a clear night. If an innovative wide field tool
Speaker 2: like eighty days can fundamentally rewrite our understanding of galactic evolution,
Speaker 2: increasing our knowledge of these massive structures by a factor
Speaker 2: of ten, and finding thirty thousand new cosmic leviathans simply
Speaker 2: by analyzing the dark spaces between the galaxies we were
Speaker 2: already studying. What other massive invisible structures are currently floating
Speaker 2: right in front of our telescope lenses, just waiting for
Speaker 2: us to figure out the right way to see them,