How Supermassive Black Holes Grew So Fast in the Early Universe

<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>Okay, I want you to imagine something for a moment.
<v Speaker 2>Just picture this. You're walking down a regular street on
<v Speaker 2>a I don't know, a regular Tuesday.
<v Speaker 3>Got with you so far, and you.
<v Speaker 2>Pass by a playground, you know the kind, right, the
<v Speaker 2>ones with the rubber mulch and those bright yellow slides.
<v Speaker 3>Standard playground scene.
<v Speaker 2>You see a toddler near the sandbox, A cute kid,
<v Speaker 2>maybe two years old, right, wearing those little velcrow sneakers.
<v Speaker 2>Maybe they have a pacifier clip to their shirt, the
<v Speaker 2>whole deal. I've got the visual, right, But then you
<v Speaker 2>look a little closer, you squint, and you realize this
<v Speaker 2>toddler is actually seven feet tall, okay, and they weigh say,
<v Speaker 2>three hundred and fifty pounds of pure rippling muscle, and
<v Speaker 2>right at that moment, they are dunking a basketball on
<v Speaker 2>a regulation hoop with the ferocity of a prime Shaquille
<v Speaker 2>O'Neal just shatters the backboard.
<v Speaker 3>That is a deeply unsettling image it is, isn't it.
<v Speaker 3>It feels like a glitch in reality. Something is profoundly
<v Speaker 3>wrong with that picture.
<v Speaker 2>It brace your brain a little because biologically, I mean physically,
<v Speaker 2>that just shouldn't be plussible. Yeah, a human body needs
<v Speaker 2>time to accumulate that much mass. You can't just cram
<v Speaker 2>twenty years of cell division and bone density growth and
<v Speaker 2>all that muscle development into twenty four months of life.
<v Speaker 2>It completely defies the laws of nature as we know them.
<v Speaker 3>It sounds like the setup for a horror movie, honestly,
<v Speaker 3>The Impossible Child exactly.
<v Speaker 2>But here's the thing. This isn't a horror movie. This
<v Speaker 2>is the exact crisis that astronomers have been waking up
<v Speaker 2>to every single morning for the last few years.
<v Speaker 3>And you aren't, I hope, talking about giant babies.
<v Speaker 2>Thankfully, No, we are talking about black holes, specifically black
<v Speaker 2>holes in the very very early universe. The James Webb
<v Speaker 2>Space Telescope, the JWST, has been acting like a time
<v Speaker 2>machine right It's peering back into this cosmic nursery.
<v Speaker 3>Right the dawn of time practically, and it.
<v Speaker 2>Keeps finding these, for lack of a better term, toddler
<v Speaker 2>black holes.
<v Speaker 3>And by toddler we mean they exist when the universe
<v Speaker 3>was in its absolute infancy.
<v Speaker 2>Absolute infancy we're talking about of time just a few
<v Speaker 2>hundred million years after the Big Bang in cosmic terms,
<v Speaker 2>that is, you know, moments after the starting gun went off.
<v Speaker 3>It's nothing, a blink of an eye.
<v Speaker 2>But here's the kicker, these toddlers. They're inexplicably massive. We're
<v Speaker 2>talking millions of times the mass of.
<v Speaker 3>Our own son, which just presents this enormous problem for physics.
<v Speaker 2>It's total paradox physics as we understand it says. They
<v Speaker 2>shouldn't have had enough time to eat enough matter to
<v Speaker 2>get that big. It's the giant Toddler all over again.
<v Speaker 2>You can't eat enough purade carrots in two years to
<v Speaker 2>become Shaquille O'Neal. It's a genuine cosmic conundrum, it really is.
<v Speaker 3>I mean, it's one of those fundamental problems that makes
<v Speaker 3>scientists just you know, pull their hair out right, because
<v Speaker 3>if you follow the standard rules of astrophysics, the rules
<v Speaker 3>we've relied on for decades. The math simply does not
<v Speaker 3>add up. It's not even close.
<v Speaker 2>So you can't get from point A, which is a small,
<v Speaker 2>let's say, seed black hole.
<v Speaker 3>To point B, a super massive monster, not in the
<v Speaker 3>time allowed.
<v Speaker 2>But today we might just have the answer. We're going
<v Speaker 2>to do a deep dive into a breakthrough study that
<v Speaker 2>was published just this month, January twenty twenty six in
<v Speaker 2>the journal Nature Astronomy, and it comes from a team
<v Speaker 2>of researchers at Maynooth University in Ireland.
<v Speaker 3>This is incredibly significant work. I've been following the pre prints.
<v Speaker 3>The team was led by Doc Solmetta, who's a PhD candidate,
<v Speaker 3>along with doctor Lewis Parl and doctor John Reagan. And
<v Speaker 3>what they proposed is, well, it's fascinating.
<v Speaker 2>They are claiming to have found the missing line, the solution.
<v Speaker 2>They think they figured out how these cosmic toddlers managed
<v Speaker 2>to bulk up so fast. Yeah, and the little spoiler alert,
<v Speaker 2>it involves a chaotic, incredibly violent early universe and something
<v Speaker 2>they're calling a feeding frenzy.
<v Speaker 3>It really changes how we have to view the early universe.
<v Speaker 3>It suggests that the conditions back then allowed for a
<v Speaker 3>kind of physics that we basically never get to see
<v Speaker 3>in the local universe today.
<v Speaker 2>Okay, so let's unpack this because to really understand why
<v Speaker 2>this is such a big deal and why scientists were,
<v Speaker 2>you know, practically flipping tables before the study came out,
<v Speaker 2>we first have to understand the speed limit of.
<v Speaker 3>The universe, right, the Eddington limit.
<v Speaker 2>I want to start there. Yeah, because my assumption, and
<v Speaker 2>I think a lot of people's assumption, is that a
<v Speaker 2>black hole is just the ultimate vacuum cleaner. It eats
<v Speaker 2>whatever it wants whenever it wants. You throw a planet
<v Speaker 2>at it, it eats the planet. You throw a star
<v Speaker 2>at it, it eats the star. So why is there
<v Speaker 2>a speed limit at all?
<v Speaker 3>It's a really common misconception. We can to think of
<v Speaker 3>the gravity in a black hole as this, you know,
<v Speaker 3>irresistible on way street. Yeah, and once you cross the
<v Speaker 3>event horizon, it absolutely is. But the process of getting
<v Speaker 3>to the event horizon, the eating part, the accretion, that's
<v Speaker 3>actually really messy, messy. How Well, for a start, matter
<v Speaker 3>doesn't just fall straight in like a coin dropping into
<v Speaker 3>a well. It has angular momentum, so it swirls. Okay,
<v Speaker 3>it forms a disk around the black hole and accretion disk.
<v Speaker 3>The best analogy is probably water spiraling down a drain, right.
<v Speaker 2>You can see it picking up speed as it gets closer.
<v Speaker 3>Exactly as that material swirls. It's moving at incredibly high speeds.
<v Speaker 3>It rubs against itself. There's friction, a lot of friction,
<v Speaker 3>and friction creates heat, immense heat. We're talking millions of degrees.
<v Speaker 3>And when things get that hot in space, they glow.
<v Speaker 3>They release a tremendous amount of energy in the form
<v Speaker 3>of light or radiation.
<v Speaker 2>Right, And that's why we can see them from across
<v Speaker 2>the universe. Things like quoasars are just super bright feeding
<v Speaker 2>black holes, right, They're like the brightest flashlights in the dark.
<v Speaker 3>Precisely, a feeding black hole is actually one of the
<v Speaker 3>most luminous objects in the entire universe. But here is
<v Speaker 3>the catch, and this is the important part. Light isn't
<v Speaker 3>just brightness, Okay, Light carries momentum. It exerts pressure, radiation pressure.
<v Speaker 2>So light pushes thing it does.
<v Speaker 3>It's a tiny, almost imperceptible force to us here on Earth,
<v Speaker 3>but it's real. If you stand out in the sun,
<v Speaker 3>photons are technically pushing on your skin. Now, scale that
<v Speaker 3>up to the insane energy output of a black hole
<v Speaker 3>accretion disc. As it eats gas, it generates this brilliant radiation.
<v Speaker 3>That radiation pushes outward.
<v Speaker 2>Ah, so it's pushing against the very gas that's trying
<v Speaker 2>to fall in exactly.
<v Speaker 3>I see, you've got it. It's a cosmic traffic jam.
<v Speaker 2>It's a battle.
<v Speaker 3>It's a perfect balance of forces. You have gravity, which
<v Speaker 3>is relentlessly pulling the gas in, and then you have
<v Speaker 3>the light produced by that very same gas, which is
<v Speaker 3>pushing the gas out.
<v Speaker 2>So what happens if a black hole tries to eat
<v Speaker 2>too much, too fast, it.
<v Speaker 3>Gets too bright, The outward pressure of the light becomes
<v Speaker 3>stronger than the inward pull of gravity.
<v Speaker 2>So it literally blows its own food away.
<v Speaker 3>Precisely, it burps. For lack of more scientific.
<v Speaker 2>Term, that's amazing. It's like, okay, stick with me here.
<v Speaker 2>It's like if I tried to shovel food into my mouth,
<v Speaker 2>but I have a high powered leaf blower strapped to
<v Speaker 2>my face pointed away from me. The faster I try
<v Speaker 2>to eat, the harder the leaf blower blows the food
<v Speaker 2>right off my spoon.
<v Speaker 3>That is a very vivid analogy. But yes, yeah, that
<v Speaker 3>is essentially the mechanism. It is a self regulating system.
<v Speaker 3>The black hole basically says, okay, I'm full, and the
<v Speaker 3>radiation pressure pushes the incoming gas away, stopping the meal.
<v Speaker 2>And this limit, this balance point, that's the Eddington limit.
<v Speaker 3>That's the Eddington limit, named after Sir Arthur Eddington, the
<v Speaker 3>British astronomer. It is the cosmic speed limit for growth.
<v Speaker 3>It dictates the absolute maximum rate at which a black
<v Speaker 3>hole can consume matter under normal conditions.
<v Speaker 2>And you said this limit is strict in the local.
<v Speaker 3>Universe, the universe we see around us today, it is
<v Speaker 3>very strict. We see black holes adhering to this limit
<v Speaker 3>all the time. It's a fundament that'll check and balance.
<v Speaker 3>It's built into nature.
<v Speaker 2>And this this is where the math just completely breaks
<v Speaker 2>for those early black holes. This is why the giant
<v Speaker 2>Toddler analogy is so apps right.
<v Speaker 3>This is the absolute heart of the paradox.
<v Speaker 2>Because we're seeing these monsters in the early universe. We're
<v Speaker 2>talking black holes that are tens of thousands, sometimes millions
<v Speaker 2>of times the mass of our Sun, and they're existing
<v Speaker 2>just a few hundred million years after the big.
<v Speaker 3>Bag correct a sliver of cosmic time.
<v Speaker 2>So okay, let's just do the thought experiment. If you
<v Speaker 2>take a brand new baby black hole, say ten times
<v Speaker 2>the mass of the Sun, and you let it eat
<v Speaker 2>at the maximum possible speed, right at the Eddington limit,
<v Speaker 2>for four hundred million years straight, NonStop eating, NonStop, maximum
<v Speaker 2>efficiency eating. How big does it get? Not big enough,
<v Speaker 2>not even close.
<v Speaker 3>Not even in the same ballpark. You might, if you're
<v Speaker 3>really liking and the conditions are perfect, get to a
<v Speaker 3>few thousand solar masses.
<v Speaker 2>Maybe, but not millions. So the math is off by
<v Speaker 2>orders of magnitude.
<v Speaker 3>It is completely broken. It's like finding that seven foot
<v Speaker 3>toddler we talked about. Yeah, you can do the math
<v Speaker 3>on how many calories a baby can consume, how fast
<v Speaker 3>bones can physically grow. If you see a giant toddler,
<v Speaker 3>you know something else that's happening. You know the rules
<v Speaker 3>you thought applied, Just don't.
<v Speaker 2>Doctor Lewis Pearl from the research team, he actually called
<v Speaker 2>this one of astronomy's big puzzles. It's like finding a
<v Speaker 2>skyscraper that was somehow built in a single day. Right,
<v Speaker 2>you walk by the construction site. You know, the concrete
<v Speaker 2>shouldn't even me dry yet, but there it is. So
<v Speaker 2>The big question is how did they cheat? How did
<v Speaker 2>they break the cosmic speed limit?
<v Speaker 3>And that is exactly where the Maynooth University study comes in.
<v Speaker 3>And what's so interesting is how they discovered this. They
<v Speaker 3>didn't find it by finding a new object in the sky.
<v Speaker 3>They didn't purn a telescope at a specific star and
<v Speaker 3>see it eating too fast.
<v Speaker 2>No, so how did they find it?
<v Speaker 3>They found it by building the early universe inside a computer.
<v Speaker 2>I love when they do this. It's one thing to
<v Speaker 2>have telescopes looking back in time, but sometimes you need
<v Speaker 2>a simulation to actually understand what you're seeing. Feels a
<v Speaker 2>bit like running a simulation in the matrix.
<v Speaker 3>It is in a way. I mean, simulations are absolutely
<v Speaker 3>crucial for this kind of work. Because we can't watch
<v Speaker 3>a black hole grow in real time.
<v Speaker 2>Right it takes millions of years. We don't have that
<v Speaker 2>kind of time exactly.
<v Speaker 3>But in a computer, we can fast forward, we can
<v Speaker 3>tweak the variables. We can say, okay, what if the
<v Speaker 3>gas was denser here, or what if two galaxies merged?
<v Speaker 3>We can replay history over and over.
<v Speaker 2>So what do they do? Do they just turn off
<v Speaker 2>the Eddington limit and the code? Did they just toggle
<v Speaker 2>cheap mode on.
<v Speaker 3>Hey, no, not exactly. That wouldn't be very scientific. What
<v Speaker 3>they did was they used these state of the art
<v Speaker 3>simulations to model the very first generation of black holes
<v Speaker 3>in their natural.
<v Speaker 2>Habitat, so in the conditions of the early universe.
<v Speaker 3>Precisely, they wanted to see if there were any physical conditions,
<v Speaker 3>any set of circumstances, under which that speed limit, the
<v Speaker 3>Eddington limit, could be broken naturally without inventing new physics.
<v Speaker 2>Did they find it?
<v Speaker 3>And they found a loophole.
<v Speaker 2>Of course, there's a loophole. Nature always finds a way
<v Speaker 2>to do, isn't it.
<v Speaker 3>They found a mechanism they call super Eddington accretion.
<v Speaker 2>Super Eddington accretion. That sounds like a marketing term for
<v Speaker 2>a very intense protein shake. Now it's super Eddington accretion
<v Speaker 2>for maximum cosmic gains.
<v Speaker 3>In a way, it is exactly that for a black hole.
<v Speaker 3>It describes a scenario where a black hole manages to
<v Speaker 3>consume matter much much faster than what is considered normal
<v Speaker 3>or you know, safe.
<v Speaker 2>But wait a minute, go back to the leaf blower,
<v Speaker 2>go back to the radiation pressure. If the physics says,
<v Speaker 2>too much food creates too much light, which pushes the
<v Speaker 2>food away. How do you bypass that? How do they
<v Speaker 2>keep eating without blowing all their food away?
<v Speaker 3>The simulation revealed that this is only possible because the
<v Speaker 3>early universe was fundamentally different from the universe we see today.
<v Speaker 3>It wasn't polite, it wasn't orderly.
<v Speaker 2>It was chaotic, chaotic, how like, just messy, extremely dense.
<v Speaker 3>You have to picture the first galaxies as they're forming.
<v Speaker 3>These weren't the neat, grand spiral shapes we see today,
<v Speaker 3>like our Milky Way or Andromeda. These were messy, clumpy
<v Speaker 3>blobs of gas collapsing rapidly under their own gravity. The
<v Speaker 3>environments were incredibly rich in gas and dust, just a
<v Speaker 3>thick cosmic soup.
<v Speaker 2>Okay, so it's extremely crowded. There's food everywhere.
<v Speaker 3>So much food. Yeah, So to go back to your
<v Speaker 3>creative analogies, imagine the inflow of food is not a spoon, Okay.
<v Speaker 3>Imagine it is a fire hose, a high pressure fire
<v Speaker 3>hose of matter aimed directly at the black hole.
<v Speaker 2>Okay, So, sticking with my analogy, Instead of the burp
<v Speaker 2>of light blowing the scone away, imagine someone is blasting
<v Speaker 2>me in the face with a fire hose of porridge.
<v Speaker 3>If you want to stick with that slightly disturbingly messy analogy,
<v Speaker 3>then yes, that's the idea.
<v Speaker 2>I'm committed to it.
<v Speaker 3>Now.
<v Speaker 2>We're in too deep to turn back.
<v Speaker 3>All right. So the inflow of gas from the surrounding
<v Speaker 3>environment is so intense and so dense that even though
<v Speaker 3>the black hole is producing these massive amounts of radiation
<v Speaker 3>to push it back, the sheer weight and momentum of
<v Speaker 3>the incoming food just overpowers the radiation.
<v Speaker 2>The food wins the fight.
<v Speaker 3>The food wins. And not only that, the radiation actually
<v Speaker 3>gets trapped. It's a phenomenon called photon trapping. The gas
<v Speaker 3>is falling in so fast that it literally drags the
<v Speaker 3>light down with it before the light has a chance
<v Speaker 3>to escape and push back out.
<v Speaker 2>Wow, So the burp never escapes. It just gets swallowed
<v Speaker 2>along with everything else. The safety valve fails completely.
<v Speaker 3>Exactly, the safety valve fails. Daxelmeta, the lead researcher on
<v Speaker 3>the paper, described it perfectly as a feeding frenzy.
<v Speaker 2>That's such a visceral image, a feeding frenzy. It sounds
<v Speaker 2>like sharks in the water.
<v Speaker 3>It's the perfect term for it. They found that in
<v Speaker 3>these specific chaotic conditions which crucially were common in the
<v Speaker 3>early universe. The black holes could just gorge themselves. They
<v Speaker 3>could grow spectacularly fast, far far beyond the Eddington limit.
<v Speaker 2>And this solves the timing problem. This gets the Toddler
<v Speaker 2>to be seven feet tall.
<v Speaker 3>It does. If you allow for these periods of super
<v Speaker 3>Eddington accretion, this rapid unsafe fire hose style of eating.
<v Speaker 3>You can take a relatively small black hole and turn
<v Speaker 3>it into a giant in a very short cosmic timeframe.
<v Speaker 3>You don't need hundreds and millions of years of slow,
<v Speaker 3>steady growth. You just need a short, intense period of
<v Speaker 3>absolute gluttony.
<v Speaker 2>This is huge. But I want to pause here for
<v Speaker 2>a second because this actually leads us straight into another
<v Speaker 2>massive debate in astronomy. This study doesn't just explain how
<v Speaker 2>they grew. It might settle a long running fight about
<v Speaker 2>where they started.
<v Speaker 3>The Battle of the seeds.
<v Speaker 2>The Battle of the Seeds. It sounds like a bad
<v Speaker 2>sci fi movie from the seventies, But this is a
<v Speaker 2>real scientific debate, right, Oh.
<v Speaker 3>Absolutely yeah, And it has divided the astrophysics community for
<v Speaker 3>quite a while. It's one of those fundamental fork in
<v Speaker 3>the road moments for the theory.
<v Speaker 2>Okay, so for you listening, let's at the stage here
<v Speaker 2>when we talk about seeds, we're talking about baby black holes.
<v Speaker 2>The starting point the little acorn that grows into the
<v Speaker 2>giant oak tree. And there have been two main candidates
<v Speaker 2>for how a super massive black hole begins its life.
<v Speaker 3>Correct, You've got candidate A and candidate B.
<v Speaker 2>Let's start with candidate A.
<v Speaker 3>The light seeds, right, light seeds are what we would
<v Speaker 3>consider the garden variety black holes. They're the ones we
<v Speaker 3>understand best, the ones we see forming today. They form
<v Speaker 3>when a really massive star dies and its core collapses.
<v Speaker 2>This is the classic black hole origin story. A huge
<v Speaker 2>star runs out of fuel, it can't support its own weight,
<v Speaker 2>it goes supernova, the core collapses in on itself, and boom,
<v Speaker 2>you've got a black hole, exactly.
<v Speaker 3>And these start out relatively small, you know, maybe ten
<v Speaker 3>to a few hundred times the mass of our sun.
<v Speaker 2>Which to me sounds incredibly heavy, but I guess on
<v Speaker 2>a cosmic scale it's.
<v Speaker 3>Peanuts, precisely peanuts. And this was always the central problem.
<v Speaker 3>If you start with a peanut light seed and you
<v Speaker 3>have to follow the cosmic speed limit, the Eddington limit.
<v Speaker 2>You can't get there.
<v Speaker 3>You cannot get to a million solar masses in time
<v Speaker 3>for the Jans Web telescope to see you in the
<v Speaker 3>early universe.
<v Speaker 2>You start too far behind the starting line. It's like
<v Speaker 2>you're trying to run a marathon, but everyone else started
<v Speaker 2>at mile twenty and you're starting back at the block.
<v Speaker 3>Right, You're guaranteed to lose the race. And because the
<v Speaker 3>math just didn't work for light seeds, scientists were forced
<v Speaker 3>to look for an alternative, a different starting.
<v Speaker 2>Point, which led them to propose candidate be the heavy seeds.
<v Speaker 3>The heavy seeds, now, this is a much more exotic
<v Speaker 3>and frankly theoretical idea. The theory is that under very rare,
<v Speaker 3>very specific conditions, enormous clouds of primordial gas could collapse
<v Speaker 3>directly into a black hole.
<v Speaker 2>So skipping the whole star phase entirely.
<v Speaker 3>Completely skipping the starphase, no star forms, no supernova happens.
<v Speaker 3>You just have this huge cloud of gas that, in
<v Speaker 3>one catastrophic event, collapses straight down into a black hole.
<v Speaker 2>And how big would these heavy seeds be from the
<v Speaker 2>get go massive?
<v Speaker 3>The model suggests they could be up to one hundred
<v Speaker 3>thousand times the mass of the Sun right at birth.
<v Speaker 2>Whoa so they get a massive head start. They're not
<v Speaker 2>starting at the block, They're starting the race at the
<v Speaker 2>twenty five mile mark exactly.
<v Speaker 3>And for a long time most astronomers thought heavy seeds
<v Speaker 3>were required. They looked at the monsters jwst was finding
<v Speaker 3>and said, there is simply no way a light seed
<v Speaker 3>could get this big, this fast. It must have started
<v Speaker 3>as a heavy seed. It was the only way the
<v Speaker 3>math worked without breaking the Eddington limit.
<v Speaker 2>But there's a big catch with heavy seeds, isn't there
<v Speaker 2>a pretty significant one?
<v Speaker 3>There is a very big catch. You don't really know
<v Speaker 3>if they exist. We've never seen one that.
<v Speaker 2>Does seem like a significant problem, you know, basing your
<v Speaker 2>entire theory on something that might be completely imaginary.
<v Speaker 3>It is a problem. Yes, heavy seeds require conditions that
<v Speaker 3>are just incredibly difficult to produce. You need a gas
<v Speaker 3>cloud that is pristine, absolutely no heavy elements, no metals,
<v Speaker 3>no pollution from other stars. Okay, you need to keep
<v Speaker 3>it hot so it doesn't fragment and form lots of
<v Speaker 3>little stars. You needed to radiate away energy in a
<v Speaker 3>very specific way. They are as doctor John Reagan from
<v Speaker 3>the main Uth team put it exotic.
<v Speaker 2>So you need everything to go perfectly flawlessly right to
<v Speaker 2>get one of these direct collapse black holes.
<v Speaker 3>It's like a cosmic hole in one. So the community
<v Speaker 3>was left with this choice. On one hand, you have
<v Speaker 3>light seeds. They're common, we know they exist, but they're
<v Speaker 3>too small to work with the old rules.
<v Speaker 2>And on the other hand, you have heavy seeds. They're
<v Speaker 2>the perfect size. They solve the problem, but they might
<v Speaker 2>be total fiction.
<v Speaker 3>That was the dilemma, exactly common but inadequate versus perfect
<v Speaker 3>but maybe impossible.
<v Speaker 2>And this is where the Manooth study just completely flips
<v Speaker 2>the table completely.
<v Speaker 3>Doctor Reagan said it himself. Now we're not so sure.
<v Speaker 3>The simulation showed that you don't need the exotic, rare
<v Speaker 3>perfect heavy.
<v Speaker 2>Seeds because of the feeding frenzy.
<v Speaker 3>Exactly. If you have that feeding frenzy, that period of
<v Speaker 3>super Eddington accretion, then a regular boring garden variety light
<v Speaker 3>seed can grow fast enough to do the job.
<v Speaker 2>So the underdog wins the race. The common explanation works.
<v Speaker 3>After all, the underdog wins. You can start small, just
<v Speaker 3>ten solar masses, and as long as the environment around
<v Speaker 3>you is chaotic enough, as long as you have that
<v Speaker 3>fire hose of gas blasting you, you can become a titan.
<v Speaker 2>This feels like a huge paradigm shift. It tells us
<v Speaker 2>we don't need to invent new rare types of magic
<v Speaker 2>black holes to explain the universe. We see right, the
<v Speaker 2>neurmal ones can do it. You just have to give
<v Speaker 2>them an endless maffe and a really violent restaurant.
<v Speaker 3>It makes the universe a little less complicated in terms
<v Speaker 3>of its ingredients. We don't need to invent new ingredients,
<v Speaker 3>but it makes it much more violent and chaotic in
<v Speaker 3>terms of its process.
<v Speaker 2>Let's talk about that violence, because I think we, you
<v Speaker 2>and I sitting here, have a very sanitized view of space.
<v Speaker 2>We look up at the night sky. It's quiet, it's still,
<v Speaker 2>the stars just twinkled gently. It looks peaceful.
<v Speaker 3>It's very peaceful from our vantage point. Yeah, but that's
<v Speaker 3>because we're looking at a snapshot of a well, a
<v Speaker 3>retired universe.
<v Speaker 2>A retired universe. I like that.
<v Speaker 3>Well compared to the early days, Yes, today galaxies are
<v Speaker 3>relatively stable. Our Milky Way isn't colliding with anything major
<v Speaker 3>At the moment. We live in a mature universe. The
<v Speaker 3>chaotic dinner party is over, and now everyone is sitting
<v Speaker 3>down with their coffee and dessert laps.
<v Speaker 2>The coffee and dessert phase of the universe. I love it.
<v Speaker 3>But the Mainnooth simulation suggests the early universe was a
<v Speaker 3>chaotic nursery. Doctor Reagan described it as being much more
<v Speaker 3>chaotic and turbulent than we'd expected.
<v Speaker 2>Chaotic nursery. That sounds like my house on a Saturday
<v Speaker 2>morning with my kids.
<v Speaker 3>Well, imagine that. But on a galactic scale, you have
<v Speaker 3>to try and visualize galaxies that aren't fully formed yet.
<v Speaker 3>They're constantly colliding and merging. Huge streams of cold gas
<v Speaker 3>are streaming in from the cosmic web, just smashing into
<v Speaker 3>the galactic center.
<v Speaker 2>So it's not empty space.
<v Speaker 3>Not at all. Stars are forming and dying at a
<v Speaker 3>furious rate, exploding a supernovae, churning everything up. It wasn't
<v Speaker 3>a quiet emptiness. It was a dense, loud, violent, and
<v Speaker 3>frankly very messy place.
<v Speaker 2>And because of that chaos, the study found another surprise.
<v Speaker 2>It's about the sheer number the population of these black holes.
<v Speaker 3>Yes, this is a really key finding. See if you
<v Speaker 3>need heavy seeds, those exotic direct collapse ones, then super
<v Speaker 3>massive black holes should be rare because the conditions needed
<v Speaker 3>to make a heavy seed are incredibly.
<v Speaker 2>Rare, so rare seeds equals rare giants. If the seed
<v Speaker 2>needs a perfect, pristine gas cloud that's never been touched,
<v Speaker 2>there can't be that many of them.
<v Speaker 3>Exactly right. But if you can make a giant from
<v Speaker 3>a light seed, which are just formed from normal massive stars,
<v Speaker 3>then massive black holes should.
<v Speaker 2>Be everywhere because stars are everywhere.
<v Speaker 3>Stars are everywhere. Yeah, And since the simulation shows that
<v Speaker 3>this chaotic, gas rich environment was the norm back then,
<v Speaker 3>not the.
<v Speaker 2>Exception, the conditions for this feeding frenzy were common Exactly.
<v Speaker 3>The simulations suggest there should be a much much larger
<v Speaker 3>population of massive black holes in the early universe than
<v Speaker 3>we ever anticipated. It wasn't just a few isolated monsters
<v Speaker 3>getting lucky. This kind of rapid growth might have been
<v Speaker 3>happening all over the place.
<v Speaker 2>That is a wild thought, Just these invisible monsters growing
<v Speaker 2>in the dark everywhere you look. It suggests the early
<v Speaker 2>universe was just teeming with these rapidly growing black holes.
<v Speaker 3>It completely changes the map. Just that if we could
<v Speaker 3>look back with perfect vision, we wouldn't just see a
<v Speaker 3>few bright spots where quasars are. We'd see a swarm
<v Speaker 3>of these things growing and.
<v Speaker 2>This brings us to this idea of the missing link.
<v Speaker 2>The researchers use this term specifically, How does this specific mechanism,
<v Speaker 2>this feeding frenzy, connect all the dots.
<v Speaker 3>Well, just look at the timeline of the universe. We
<v Speaker 3>have the first stars, we know they existed, we can
<v Speaker 3>see their chemical signatures in later stars, the relatively.
<v Speaker 2>Small Okay Porne.
<v Speaker 3>Then you fast forward a few billion years and we
<v Speaker 3>have the super massive black holes, the behemoths that we
<v Speaker 3>see today at the centers of nearly every large galaxy.
<v Speaker 2>Like Sagittarius A at the center of our own Milky.
<v Speaker 3>Way, exactly millions or even billions of times the mass
<v Speaker 3>of the Sun. That's point B. The gap has always
<v Speaker 3>been how do you get from the small star to
<v Speaker 3>the big hole?
<v Speaker 2>The middle steps were missing. It was like seeing a
<v Speaker 2>baby picture of someone and then a picture of them
<v Speaker 2>as a CEO, with absolute nothing in between, no school photos,
<v Speaker 2>no awkward teenage years.
<v Speaker 3>That's a perfect analogy, and Duxhall, the lead author, points
<v Speaker 3>out that this research connects the two. It fills in
<v Speaker 3>those missing photos. It explains how the small black holes
<v Speaker 3>left behind by the very first stars could transition into
<v Speaker 3>the behemoth black holes that anchor galaxies.
<v Speaker 2>It fills in the blank pages of cosmic history.
<v Speaker 3>It does it says this is how they did it.
<v Speaker 3>They ate their way there.
<v Speaker 2>So we have the theory, we have the simulation, we
<v Speaker 2>have the how. But you know what I'm going to.
<v Speaker 3>Ask next, You get asked for proof.
<v Speaker 2>I am I'm a skeptic at heart, As you always
<v Speaker 2>tell me. A simulation is just a really well informed
<v Speaker 2>prediction until you can prove it. It's a very nice
<v Speaker 2>computer model, but is it real life?
<v Speaker 3>True science demands verification. A theory without some kind of
<v Speaker 3>observable proof is just a nice story.
<v Speaker 2>So how do we verify this? We can't exactly build
<v Speaker 2>a time machine and go back and watch the meat.
<v Speaker 3>No we can't. But we can listen for them.
<v Speaker 2>Uh. Now we are getting into the really cool sci
<v Speaker 2>fi stuff. And you don't mean listening with a giant microphone.
<v Speaker 3>No, there is no sound in space, as the movie
<v Speaker 3>posters famously say. We are talking about listening for gravitational.
<v Speaker 2>Waves, the ripples in space time itself.
<v Speaker 3>Right, and the study points directly to a future mission
<v Speaker 3>that is going to be absolutely critical for proving or
<v Speaker 3>disproving this theory. It's called LISA.
<v Speaker 2>LISA the Laser Interferometer Space Antenna.
<v Speaker 3>Correct, it's a joint mission between the European Space Agency
<v Speaker 3>ESA and NASA, and it's currently scheduled to launch in
<v Speaker 3>twenty thirty five.
<v Speaker 2>That feels like a long way off, but I guess
<v Speaker 2>in space mission terms, that's practically tomorrow. They are probably
<v Speaker 2>building parts of it as we speak.
<v Speaker 3>They are. And LISA is special. Think about what JWST does.
<v Speaker 3>It's a telescope.
<v Speaker 2>It looks at infrared light. It takes pictures, it captures photons.
<v Speaker 3>Right, it sees light, but light can be blocked by
<v Speaker 3>dust and gas, and light from the very very beginning
<v Speaker 3>of the universe is hard to interpret because it's been
<v Speaker 3>stretched and red shifted. LISA is different. It's an observatory
<v Speaker 3>design to detect gravitational waves.
<v Speaker 2>So when these massive objects like black holes collide or merge,
<v Speaker 2>they physically shake the universe.
<v Speaker 3>They do. Einstein predicted this over one hundred years ago.
<v Speaker 3>When two massive objects spiral into each other and merge,
<v Speaker 3>they disrupt the very fabric of space time itself. They
<v Speaker 3>send out these powerful waves like the ripples in a
<v Speaker 3>pond when you throw a rock in, and.
<v Speaker 2>We can actually detect those ripples.
<v Speaker 3>Here on Earth we already have with the ground based
<v Speaker 3>detectors like Lego and Virgo, but they can only hear
<v Speaker 3>the high notes of the universe, the quick, sharp crashes
<v Speaker 3>of smaller stellar mass black holes. Lisa is going to
<v Speaker 3>be in space. It will be three separate spacecraft flying
<v Speaker 3>in a perfect triangle formation, millions of kilometers wide, constantly
<v Speaker 3>firing lasers at each other to measure their exact distance.
<v Speaker 2>That is just insanely cool. A triangle of lasers bigger
<v Speaker 2>than the orbit of the Earth around the Sun.
<v Speaker 3>It is the ultimate listening device. And because its arms
<v Speaker 3>are so long, it can hear the low notes. It
<v Speaker 3>can hear the slow, deep rumbles of supermassive black holes merging,
<v Speaker 3>and importantly, it can hear the mergers of these seed
<v Speaker 3>black holes back in the early universe.
<v Speaker 2>So how does this prove the MANU theory specifically, Well, if.
<v Speaker 3>The MAINU researchers are right, the early universe was this
<v Speaker 3>chaotic nursery absolutely full of these light seeds growing rapidly
<v Speaker 3>through these feeding frenzies in such a crowded, chaotic place.
<v Speaker 3>That means it should be a lot of mergers, a
<v Speaker 3>lot of collisions between these growing black holes.
<v Speaker 2>A lot of gravitational noise, a cosmic cacophony.
<v Speaker 3>If the simulation is right, loss is going to hear
<v Speaker 3>a constant background hum from that era. It will be
<v Speaker 3>the smoking gun. If we hear that specific frequency of mergers,
<v Speaker 3>the sound of these intermediate mass, rapidly growing light seeds
<v Speaker 3>crashing into each other while gorging on gas. That proves
<v Speaker 3>they were there, and they were growing this way.
<v Speaker 2>And if we turn it on and we don't hear
<v Speaker 2>that sound, if it's quiet, then the theory.
<v Speaker 3>Is probably wrong. Back to the drawing board. Perhaps the
<v Speaker 3>heavy seeds are real after all, but the simulation makes
<v Speaker 3>a very specific, testable prediction. We should hear them. Wise,
<v Speaker 3>I should hear them.
<v Speaker 2>So instead of just seeing a break, Quasar will be
<v Speaker 2>able to hear the chaos of their growth. It really
<v Speaker 2>adds a whole new sense to astronomy, doesn't it.
<v Speaker 3>Precisely, it allows us to build a census of the
<v Speaker 3>early black hole population, not by looking for their light,
<v Speaker 3>but by listening to the sounds of their crashes.
<v Speaker 2>It really is incredible how all these different pieces of
<v Speaker 2>science fit together. We start with a paradox from a
<v Speaker 2>space telescope an impossible toddler. We use supercomputers to simulate
<v Speaker 2>a chaotic cosmic dining room. We realize the standard diet
<v Speaker 2>plan the Eddington limit doesn't apply because the food is
<v Speaker 2>being force fed, and now we are building giant laser
<v Speaker 2>ears in space to listen for the evidence.
<v Speaker 3>It's the scientific method in perfect action. You see an anomaly,
<v Speaker 3>you model a potential solution. Then you make a prediction
<v Speaker 3>for what future observations we'll find.
<v Speaker 2>I want to circle back to something you said earlier
<v Speaker 2>about the ingredients of the universe. Sure, I find it
<v Speaker 2>oddly comforting that we might not need these exotic heavy seeds.
<v Speaker 2>There's something very elegant about the idea that the universe
<v Speaker 2>is built from simple common blame. You start with a star.
<v Speaker 2>That's it. You don't need a special one in a
<v Speaker 2>billion miracle cloud to make a monster. You just need
<v Speaker 2>a regular star and a whole lot of chaos.
<v Speaker 3>It is elegant. It follows a principle we often see
<v Speaker 3>in science called Okham's razor. The simplest explanation is often
<v Speaker 3>the best. It suggests that the complexity we see arises
<v Speaker 3>from the environment, not necessarily from the origin.
<v Speaker 2>Context is everything it is.
<v Speaker 3>In a calm, orderly universe, a light seed black hole
<v Speaker 3>starves and stays small. In a chaotic one, it becomes
<v Speaker 3>a giant.
<v Speaker 2>That's a profound thought. We usually think of chaos as
<v Speaker 2>a bad thing. We want order, we want stability. If
<v Speaker 2>I told you your child's nursery was a chaotic, violent place,
<v Speaker 2>you'd call social services.
<v Speaker 3>You absolutely would, and rightly so.
<v Speaker 2>But in this case, for the universe, chaos was the
<v Speaker 2>engine of creation.
<v Speaker 3>Absolutely. Without that turbulence, without that violence and those chaotic
<v Speaker 3>gas flows, the black holes wouldn't have grown fast enough.
<v Speaker 3>And if they hadn't grown, they wouldn't have been massive
<v Speaker 3>enough to act as the gravitational anchors for the galaxies
<v Speaker 3>that formed around them later. The structure of our modern, stable,
<v Speaker 3>coffee drinking universe we live in today owes its very
<v Speaker 3>existence to that early chaos.
<v Speaker 2>The chaos was a necessary constructive phase.
<v Speaker 3>It was the construction phase. You can't live peacefully in
<v Speaker 3>a house while it's being built. It's loud, it's dusty,
<v Speaker 3>it's dangerous. But once it's built, it provides a safe,
<v Speaker 3>stable home. We live in the house that chaos built.
<v Speaker 2>So let's just recap this big aha moment for everyone listening,
<v Speaker 2>because we've covered a lot of heavy physics here and
<v Speaker 2>I want to make sure we really nail the takeaway.
<v Speaker 3>Let's do it.
<v Speaker 2>So the mystery how did black holes get so big
<v Speaker 2>so fast in the early universe the impossible Toddler paradox
<v Speaker 2>found by jwst The.
<v Speaker 3>Old theory, maybe they started out big to begin with
<v Speaker 3>the heavy seeds, but we couldn't prove those seeds actually existed,
<v Speaker 3>and they required a set of physical conditions that was
<v Speaker 3>a bit too perfect, a bit too convenient.
<v Speaker 2>The new theory from this Manuth study they didn't need
<v Speaker 2>to start big. They started small, as normal common black
<v Speaker 2>holes from the first stars the light.
<v Speaker 3>Seats, but the environment they were born in to completely
<v Speaker 3>change the rules of the game. The early universe was
<v Speaker 3>a chaotic, dense, gas rich all you can eat buffet, and.
<v Speaker 2>In that chaotic buffet they were able to break the
<v Speaker 2>cosmic speed limit. They went into a state of super
<v Speaker 2>Addington accretion.
<v Speaker 3>They entered a feeding frenzy. The gas fell in so
<v Speaker 3>fast that it trapped its own radiation, preventing the burp
<v Speaker 3>and allowing the black hole to consume matter at an
<v Speaker 3>absolutely exponential.
<v Speaker 2>Rate, turning a cosmic peanut into a monster in the
<v Speaker 2>blink of a cosmic eye.
<v Speaker 3>And solving the paradox of the JWST observations without needing
<v Speaker 3>to invent any new or exotic physics.
<v Speaker 2>It's a fantastic story, and it really makes you wonder
<v Speaker 2>what else is out there hiding? What do you mean, well,
<v Speaker 2>if the early universe was this dense, violent, screaming nursery
<v Speaker 2>full of these invisible monsters just gorging themselves on gas,
<v Speaker 2>what else is hiding in that data? What other impossible
<v Speaker 2>things were happening?
<v Speaker 3>That is the big question, isn't it.
<v Speaker 2>We're so focused on the things we can see with
<v Speaker 2>light or the things we expect to see based on
<v Speaker 2>our quiet universe, But this study shows that processes we
<v Speaker 2>thought were impossible, like breaking the Eddington limits so dramatically,
<v Speaker 2>we're actually happening all over the place, right under our noses,
<v Speaker 2>or you know, billions of years ago and billions of
<v Speaker 2>light years away.
<v Speaker 3>It's a good reminder to always keep an open mind.
<v Speaker 3>We build our models based on the physics we know
<v Speaker 3>and can observe here today, but the universe has gone
<v Speaker 3>through these incredible phases where the effective rules of the
<v Speaker 3>game were just different.
<v Speaker 2>So when Lisa launches in twenty thirty five and we
<v Speaker 2>finally turn those gravitational ears on, we might hear the
<v Speaker 2>mergers of the black holes we expect. But what if
<v Speaker 2>we also hear things we haven't even imagined yet.
<v Speaker 3>The dark ages of the cosmos might be a lot
<v Speaker 3>louder than we think.
<v Speaker 2>Indeed, it's a pretty humbling thought, isn't it. We're just
<v Speaker 2>sitting here in our quiet, calm corner of space time,
<v Speaker 2>listening to the faint echo of an incredibly violent past, a.
<v Speaker 3>Violent past that made our quiet present possible.
<v Speaker 2>Well, that gives us plenty to think about. A universe
<v Speaker 2>born and a feeding frenzy. A huge thanks to the
<v Speaker 2>team at Maynooth University, Doxelmetta, doctor Lewis Proll and doctor
<v Speaker 2>John Reagan for giving us a glimpse into that chaotic nursery.
<v Speaker 3>It's truly fascinating work. I for one can't wait to
<v Speaker 3>see what the laysubmission brings back, or I should say,
<v Speaker 3>what it hears.
<v Speaker 2>And a big thank you to you for listening, keep
<v Speaker 2>looking up, keep listening, and keep wondering what else might
<v Speaker 2>be hiding out there?
<v Speaker 3>In the dark. Until next time, the Nassas