Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomie podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky.
Speaker 2: So I want you to just imagine something for a second. Okay,
Speaker 2: picture a ghost, but you know, not a sheet wearing
Speaker 2: hovering in a hallway.
Speaker 3: Kind of ghost, right, something a bit more substantial exactly.
Speaker 2: I'm talking about a cosmic ghost, an entity that possesses
Speaker 2: the mass of one million of our suns. That is
Speaker 2: a lot of mass, it really is. And it's just
Speaker 2: wandering entirely invisible through the dark, quiet suburbs of a
Speaker 2: distant galaxy.
Speaker 3: Just completely out in the open, but totally hidden.
Speaker 2: Yeah, because it emits absolutely zero light. I mean, it
Speaker 2: makes no sound. It is a perfect voice drifting through
Speaker 2: the blackness of space.
Speaker 3: It is the ultimate cosmic ambush, really.
Speaker 2: Right, And the only reason we even know this staggering
Speaker 2: thing is out there, the only reason we can perceive
Speaker 2: it at all is because it just violently ate a star, a.
Speaker 3: Million solar masses of pure gravity, completely hidden until the
Speaker 3: exact moment a star takes one wrong step.
Speaker 2: And today is July twenty seven, twenty twenty six, and
Speaker 2: the entire world of astronomy just realized they were looking
Speaker 2: at a massive reality bending paradigm shift.
Speaker 3: Because it completely breaks the rules we thought we knew.
Speaker 2: It totally does because we are looking at the discovery
Speaker 2: of one of the universe's absolute rarest events. I'm talking
Speaker 2: about a supermassive black hole, a true monster that is
Speaker 2: not where it is supposed to be.
Speaker 3: It's tens of thousands of light years away from its
Speaker 3: designated home.
Speaker 2: Right. It is a rogue, a wanderer. But you know,
Speaker 2: before we get to the fact that this black hole
Speaker 2: is wandering through the galactic suburbs, we really need to
Speaker 2: set the scene.
Speaker 3: Yeah, we have to talk about the catalyst.
Speaker 2: Exactly, the murder scene itself. What exactly happens physically when
Speaker 2: a star wanders too close to an invisible monster.
Speaker 3: Well, the actual scientific term for this catalyst is a
Speaker 3: tidal disruption event, or we usually just call it a TDE.
Speaker 2: A TDE, got it, And it is.
Speaker 3: Truly one of the most violent physical processes in the
Speaker 3: known universe. To understand what happens, you really have to
Speaker 3: look at the mechanics of gravity. Okay, specifically, you have
Speaker 3: to understand that the gravity of a supermassive black hole
Speaker 3: isn't just strong, it creates this extreme gradient.
Speaker 2: The gradient meaning the poll is significantly stronger the closer
Speaker 2: you get ragsactly, But wait, gravity always gets stronger the
Speaker 2: closer you get to something like That's just how gravity works.
Speaker 2: Why is it so extreme here that it literally shreds
Speaker 2: a star?
Speaker 3: So it has to do with the density and the
Speaker 3: extreme proximity. Imagine a star very similar to our own Sun,
Speaker 3: just tracing a path through a galaxy.
Speaker 2: Okay, tracing its path.
Speaker 3: Over millions of years. Its orbit happens to drift a
Speaker 3: little too close to this hidden million solar mass black.
Speaker 2: Hole, just a little too close.
Speaker 3: Right, And because a black hole is so incredibly dense,
Speaker 3: the star can get extremely close to the center of
Speaker 3: that mass without hitting a physical surface.
Speaker 2: Because it's a singularity, not a giant rock.
Speaker 3: Yes, So as it approaches the gravitational poll on the
Speaker 3: side of the star facing the black hole becomes exponentially
Speaker 3: stronger than the pole on the far side of the star.
Speaker 2: Oh well, okay, so if the star is say a
Speaker 2: million miles wide, the front edge of the star is
Speaker 2: a million miles deeper into the black hole's gravity well than.
Speaker 3: The back edge precisely, And that difference in gravitational pull
Speaker 3: across the diameter of the star that is what we
Speaker 3: call the tidal force.
Speaker 2: Like the tides on Earth, but cranked up to.
Speaker 3: A trillion exactly like that, and eventually that tidal force
Speaker 3: exceeds the star's own internal gravity.
Speaker 2: The force that's holding the star together is a burning
Speaker 2: sphere of plasma.
Speaker 3: Yeah, that force is simply overwhelmed by the difference in
Speaker 3: the black holes.
Speaker 2: So the star doesn't just bump into it like a
Speaker 2: car crash, No, not at all. The front is yank
Speaker 2: so much harder than the back that the star simply
Speaker 2: cannot hold itself together. It fails structurally.
Speaker 3: It is literally torn apart. The term astrophysicists sometimes use
Speaker 3: is spaghettification.
Speaker 2: Spaghettification that sounds a bit whimsical for an absolute categorism.
Speaker 3: Well I know it really does, but it's accurate. The
Speaker 3: stars stretched into a long, thin stream of superheated stellar
Speaker 3: material like a noodle, like a noodle of plasma. Yeah,
Speaker 3: but what happens next is what makes this detectable to
Speaker 3: us here on Earth, because.
Speaker 2: It doesn't just quietly fall straight down into the void.
Speaker 3: No, it definitely doesn't. The crumbs of the splintering star,
Speaker 3: this immense volume of gas and plasma, they get caught
Speaker 3: in the black hole's gravitational grip.
Speaker 2: And they start to orbit.
Speaker 3: They do. They begin to swirl around the black hole,
Speaker 3: forming what we call an accretion disc.
Speaker 2: Okay, so it's like water circling a drain, very similar, Yes,
Speaker 2: but the drain is a bottomless pit in space time,
Speaker 2: and the water is superheated plasma moving at what a
Speaker 2: fraction of the speed of light.
Speaker 3: A significant fraction of the speed of light, and that
Speaker 3: speed is the key to everything.
Speaker 2: Why is the speed so important?
Speaker 3: Because the material is orbiting so incredibly fast. The friction
Speaker 3: within the gas is unimaginable friction in space. Yeah. As
Speaker 3: the layers of plasma rub against each other in that
Speaker 3: swirling disc, they undergo intense compression.
Speaker 2: And friction, which generates heat.
Speaker 3: It heats the material to temperatures that defy human comprehension.
Speaker 3: We're talking millions of degrees.
Speaker 2: Millions of degrees. That is insane, it is.
Speaker 3: And this heat creates an incredibly brilliant glow, radiating intense
Speaker 3: ultraviolet light and X rays across the cosmos.
Speaker 2: It's basically screaming its existence out into the universe exactly.
Speaker 3: And furthermore, the immense magnetic fields and the rotational energy
Speaker 3: involved in this whole process can cause the black hole
Speaker 3: to launch a relativistic jet into space.
Speaker 2: A relativistic jet, what is that?
Speaker 3: It's basic a highly concentrated beam of energy and matter
Speaker 3: shooting outward along the poles of the black hole, moving
Speaker 3: at nearly the speed of light.
Speaker 2: So it's like a cosmic lighthouse beam. It's the universe's
Speaker 2: most dramatic dinner bell.
Speaker 3: That's a great way to put it.
Speaker 2: Because black holes themselves emit zero light. I mean, you
Speaker 2: could be looking right at one and see nothing but
Speaker 2: the darkness of space.
Speaker 3: Right. They are functionally invisible.
Speaker 2: But this tde, this destruction of the star, completely lights
Speaker 2: up the dark.
Speaker 3: Assistant Professor igor Andreoni down at UNC Chapel Hill perfectly
Speaker 3: describe these events. He called them cosmic billboards.
Speaker 2: Cosmic billboards, I like that.
Speaker 3: Yeah, because they are quite literally advertising the presence of
Speaker 3: something that would otherwise remain completely stubbornly invisible.
Speaker 2: Which is huge for astronomy.
Speaker 3: It's a scientific gold mine. Catching these events in the
Speaker 3: act illuminates the actual mechanics of how massive black holes feed.
Speaker 2: Okay, but if we are just sitting around waiting for
Speaker 2: a star to accidentally bump into an invisible black hole,
Speaker 2: how often does that actually happen?
Speaker 3: Well, space is famously.
Speaker 2: Very empty, right, so it can't be that often.
Speaker 3: It is extraordinarily rare. On average, a tidal disruption event
Speaker 3: happens only once every one hundred thousand years anywhere in
Speaker 3: a given galaxy.
Speaker 2: Wait, wait, once every one hundred thousand years for a
Speaker 2: whole galaxy.
Speaker 3: That is the average rate.
Speaker 2: Yes, but a galaxy has billions of stars, you're telling
Speaker 2: me at billions of stars circling around, this crash only
Speaker 2: happens once every hundred millennia.
Speaker 3: It is a true testament to exactly what you just said.
Speaker 3: Space is incredibly empty. The distances between stars are vast,
Speaker 3: unimaginably vast, and the distances between a star and a
Speaker 3: central black hole are even vaster. The orbital alignment required
Speaker 3: for a star to perfectly cross that fatal threshold, what
Speaker 3: we call the title radius, is mathematically highly improbable.
Speaker 2: So it can't just be passing through the neighborhood.
Speaker 3: No, It's specific trajectory has to intersect a very precise,
Speaker 3: very narrow zone right around the block.
Speaker 2: To put that one hundred thousand year timeline and perspective
Speaker 2: for you listening, one hundred thousand years ago, anatomically modern
Speaker 2: humans were just starting to seriously migrate out of Africa.
Speaker 3: It's a massive span of time.
Speaker 2: Neanderthals were still the dominant hominins in Europe back then.
Speaker 2: We've gone from stone tools to quantum computers in the
Speaker 2: time it takes for a single galaxy to produce one
Speaker 2: of these flashes.
Speaker 3: Which is exactly why in the past decade of intensive
Speaker 3: modern astronomy, with all our advanced telescopes constantly scanning the skies,
Speaker 3: astronomers have only identified a little over one hundred of
Speaker 3: these TDEs in total.
Speaker 2: One hundred across millions of galaxies.
Speaker 3: Across the millions of galaxies we can actively observe.
Speaker 2: Yes, it makes me think of an analogy. Let's hear it. Okay,
Speaker 2: imagine you are in a massive pitch black warehouse. You
Speaker 2: have absolutely no idea what's in the room, but you
Speaker 2: suspect there's a giant, invisible spinning fan blades somewhere in there. Okay,
Speaker 2: a dangerous room, very and you can't use a flashlight,
Speaker 2: you can't make a sound. The only way you can
Speaker 2: find that fan blade is by taking a glowing, exploding
Speaker 2: paint bomb and tossing it into the dark.
Speaker 3: I see where this is going, right.
Speaker 2: If you toss it and it hits the floor, nothing happens.
Speaker 2: If you toss it and hits a wall, nothing happens.
Speaker 3: Because it's not hitting the target exactly.
Speaker 2: But if you just happen to toss that paint bomb
Speaker 2: perfectly into the spinning blades, boom, it shred The paint
Speaker 2: is violently shredded. It heats up, it splatters everywhere, and suddenly,
Speaker 2: for just a brief few weeks or months, the destruction
Speaker 2: of the paint reveals the exact shape, location, and violence
Speaker 2: of the monster in the dark.
Speaker 3: That is a highly accurate visualization. Actually, the star is
Speaker 3: your paint bomb, right. The destruction of the star is
Speaker 3: the only mechanism that renders the invisible fan blade. The
Speaker 3: black hole temporarily visible.
Speaker 2: But here's the thing, fighting one of these paint BOMs.
Speaker 2: Finding a TDE is not the real paradigm shift here today,
Speaker 2: is it. No, it's not, because we found one hundred
Speaker 2: of them before. The universe breaking mystery. Here is where
Speaker 2: this specific paint bam went off.
Speaker 3: Which brings us to this specific event designated as TDE
Speaker 3: twenty twenty five ABCR.
Speaker 2: Catch you name?
Speaker 3: They always are in astronomy.
Speaker 2: So researchers track this massive flare to a nearby galaxy.
Speaker 2: It doesn't even catch your very poetic catalog name.
Speaker 3: Oh why is a JJ zero one four sixty five
Speaker 3: six point zero four one five two two fourteen point seven?
Speaker 2: Wow? You memorized that. We'll just call it the wiser
Speaker 2: galaxy for sure?
Speaker 3: That idea.
Speaker 2: Usually when we see a TDE, it's dead center in
Speaker 2: the galaxy, right, almost always. But TDE twenty twenty five
Speaker 2: ABCR happened thirty thousand light years.
Speaker 3: Away from the center, which represents the farthest offset ever
Speaker 3: observed for an optically discovered title disruption event.
Speaker 2: Thirty thousand light years. That's a massive distance.
Speaker 3: It is, and it breaks a fundamental rule that astronomers
Speaker 3: have operated under for a very long time.
Speaker 2: Which rule is that well.
Speaker 3: Jonathan Carney, who's a PhD student in physics and astronomy
Speaker 3: at UNC Chapel Hill, pointed this out very clearly. He
Speaker 3: noted that almost every title disruption event we have ever
Speaker 3: observed has occurred at the absolute sence h of a galaxy.
Speaker 2: Because that is where the giant black holes live.
Speaker 3: Exactly. The galactic nucleus is where the supermassive black holes reside.
Speaker 3: It's where the gravitational well of the galaxy is the deepest.
Speaker 2: It's like the drain at the bottom of a massive sink, right.
Speaker 3: It's where the most matter has accumulated over billions of years.
Speaker 3: That is where we expect the biggest monsters to be.
Speaker 2: So to find a tidal disruption event tens of thousands
Speaker 2: of light years away from the center.
Speaker 3: It implies there is a massive black hole lurking in
Speaker 3: a place we would normally never ever expect to find one.
Speaker 2: I have to stop you here, though, because the scale
Speaker 2: and the physics are kind of messing with my head.
Speaker 2: How So, the black hole responsible for this event is
Speaker 2: estimated to be roughly one million times the mass of
Speaker 2: our sun one million solar.
Speaker 3: Masses that is the current estimate.
Speaker 2: Yes, how on Earth do you hide something with a
Speaker 2: million solar masses in the quiet suburbs of a galaxy?
Speaker 3: I mean, I feel like it's gravity would just be
Speaker 3: completely tearing the neighborhood apart.
Speaker 2: It's a fair assumption to make be like.
Speaker 3: A cosmic vacuum cleaner when we notice all the stars
Speaker 3: around it swirling down a drain before a TD even happens.
Speaker 3: It is a very common misconception about black holes, this
Speaker 3: idea that they are cosmic vacuum cleaners.
Speaker 2: Because pop culture always shows them sucking everything in.
Speaker 3: Right, we assume something that massive must be inherently disruptive,
Speaker 3: just constantly pulling in everything around it. But you really
Speaker 3: have to remember two things here.
Speaker 2: Okay, what are they?
Speaker 3: First the sheer scale of the space we are talking about,
Speaker 3: and second, the inverse square law of gravity.
Speaker 2: Okay, let's break down the inverse square law. Yeah, that
Speaker 2: sounds like the actual key to this whole hiding trick.
Speaker 3: It absolutely is. Gravity is entirely dependent on distance. The
Speaker 3: inverse square law basically states that if you double the
Speaker 3: distance between two objects, the gravitational force doesn't just drop
Speaker 3: by half.
Speaker 2: It doesn't.
Speaker 3: No, it drops by a factor of four. It weakens
Speaker 3: exponentially the further away you get. Oh wow, if you
Speaker 3: triple the distance, the force is nine times weaker.
Speaker 2: So gravity basically falls off a cliff once you take
Speaker 2: a few steps away from the source.
Speaker 3: Precisely, let me give you a local example. If you
Speaker 3: were to replace our own Sun right now with a
Speaker 3: black hole of the exact same mass, one solar mass,
Speaker 3: Earth would not get sucked in.
Speaker 2: Wait, really, we wouldn't just spiral to our doom, not
Speaker 2: at all.
Speaker 3: The Earth would continue orbiting in the exact same path
Speaker 3: in exactly three hundred and sixty five.
Speaker 2: Days because the mass hasn't changed.
Speaker 3: Because the mass hasn't changed, and our distance hasn't changed.
Speaker 2: The only difference is that we'd all freeze and it
Speaker 2: would get very very dark.
Speaker 3: It would be a bad day for life on Earth. Yes,
Speaker 3: but gravitationally, nothing changes.
Speaker 2: So let's apply that to this wandering monster in the
Speaker 2: wiser galaxy. It has the mass of a million suns.
Speaker 3: Right, and a million solar masses is immense compared to
Speaker 3: our Sun, obviously, but on a galactic scale, it's just
Speaker 3: a drop in the ocean.
Speaker 2: Really, a million suns is a drop the.
Speaker 3: Entire galaxy weighs billions or even trillions of solar masses
Speaker 3: thirty thousand light years from the center. Puts this black
Speaker 3: hole out in the outer galactic disc, or maybe even
Speaker 3: the halo.
Speaker 2: Which is the sparsely populated part of town.
Speaker 3: Exactly. These are regions where the density of stars is
Speaker 3: significantly lower than in the packed galactic core.
Speaker 2: So it's not packed like sardines out there. The stars
Speaker 2: have a lot of elbow room, lots of rooms.
Speaker 3: So because of that inverse square law we just talked about,
Speaker 3: unless a star crosses that very specific, very narrow threshold
Speaker 3: right next to the black hole's event horizon, it will
Speaker 3: simply orbit the black hole.
Speaker 2: Safely or just pass right by it.
Speaker 3: Yes, completely unaffected in any catastrophic way.
Speaker 2: So it really isn't a vacuum cleaner at all. It's
Speaker 2: more like, Okay, it's like a really really deep pothole
Speaker 2: on a very wide, empty, dark highway. I like that, Like,
Speaker 2: if you don't drive your tire directly over it, you're
Speaker 2: totally fine. You don't even know it's there.
Speaker 3: That is a perfect way to look at it, and
Speaker 3: scientists have actually theorized for a while that these wandering
Speaker 3: black holes likely exist in massive galaxies.
Speaker 2: They suspected they were out there.
Speaker 3: Oh, definitely the mathematics when the really complex computer simulations
Speaker 3: of galactic evolution strongly suggest they should be out there
Speaker 3: wandering around.
Speaker 2: But knowing they exist in a computer model and actually
Speaker 2: finding one in the dark are two very different.
Speaker 3: Things, extremely different. As Jonathan Carney highlighted, they are notoriously
Speaker 3: difficult to study because unless they are actively feeding, unless
Speaker 3: they briefly disrupt a star like this one, did, they
Speaker 3: produce absolutely no light.
Speaker 2: They're perfectly camouflaged against the darkness of empty.
Speaker 3: Space, literally invisible.
Speaker 2: Okay, So if a one million solar mass black hole
Speaker 2: does not naturally belong in the galactic suburbs, if it's
Speaker 2: supposed to be downtown in the galactic core where it
Speaker 2: was born, how in the universe did he get thirty
Speaker 2: thousand light years away?
Speaker 3: That is the big question.
Speaker 2: I mean, what could possibly have the leverage to move
Speaker 2: an object that weighs a million times more than our sun.
Speaker 3: Well. Astrophysics offers two leading theoretical scenarios for how a
Speaker 3: supermassive black hole becomes a wanderer, A rogue drifting far
Speaker 3: from home to hear them. Both scenarios are rooted in
Speaker 3: immense violence and cosmic scale upheaval. The first theory proposes
Speaker 3: that this black hole is essentially a remnant left behind
Speaker 3: after a massive galactic merger in the distant past.
Speaker 2: Let's talk about a galactic merger for a second. We're
Speaker 2: talking about two entirely separate galaxies colliding.
Speaker 3: With each other, right, Yes, a cosmic collision. Picture a
Speaker 3: massive galaxy in a smaller satellite galaxy nearby. Over billions
Speaker 3: of years, their mutual gravitational attractions slowly dries them.
Speaker 2: Together billions of years. Yeah, so this is not a
Speaker 2: fast crash.
Speaker 3: No, it is an incredibly slow, majestic, and entirely destructive process.
Speaker 3: As the two galaxies merge, their outer halos touch first,
Speaker 3: what happens?
Speaker 2: Then?
Speaker 3: Gas clouds collide, which compresses the gas and ignites massive
Speaker 3: bursts of new star formation. It would look like fireworks
Speaker 3: on a cosmic scale.
Speaker 2: But do the actual stars crash into each other?
Speaker 3: Surprisingly? No, The stars themselves rarely collide because of the
Speaker 3: vast distance between them, but their orbits are thrown into
Speaker 3: complete and utter chaos.
Speaker 2: Okay, but what happens to the black holes because both
Speaker 2: of these galaxies started with their own supermassive black hole
Speaker 2: in their respective centers, right.
Speaker 3: Most galaxies do.
Speaker 2: Yes.
Speaker 3: Now, in a perfect symmetrical merger, the two central black
Speaker 3: holes would undergo a process called dynamical friction. Dynamical friction,
Speaker 3: they would interact with the gas and stars around them,
Speaker 3: slowly losing orbital energy, and they'd gradually sync to the
Speaker 3: center of the newly combined larger galaxy.
Speaker 2: So they sort of spiral down the new drain together exactly.
Speaker 3: Eventually they would orbit each other in a binary pair,
Speaker 3: and over millions of years, merge into one even larger
Speaker 3: supermassive black hole.
Speaker 2: That sounds very neat and orderly, but I'm guessing space
Speaker 2: isn't always that tidy.
Speaker 3: Far from it. Mergers are very messy asymmetrical events. Sometimes
Speaker 3: the smaller galaxy is essentially stripped apart before it even
Speaker 3: reaches the center.
Speaker 2: Stripped apart.
Speaker 3: How its outer layers of stars and gas are literally
Speaker 3: peeled away by the tidal forces of the larger.
Speaker 2: Galaxy, So it's just dismantled, right.
Speaker 3: And by the time the smaller galaxy is fully swallowed,
Speaker 3: its central black hole is left completely stranded because.
Speaker 2: All the stuff around it that was helping it sinc
Speaker 2: is gone.
Speaker 3: Yes, it loses its surrounding mass and never manages to
Speaker 3: sync to the new galactic core through that dynamical friction.
Speaker 3: It simply gets marooned out in the newly expanded outer
Speaker 3: halo of the merged.
Speaker 2: Galaxy, just orbiting aimlessly, just wandering. So it's basically the
Speaker 2: orphan heart of a dead, consumed galaxy, just floating through
Speaker 2: the outer ruins of its former home. That is incredibly
Speaker 2: poetic and kind of sad.
Speaker 3: It is a profound cosmic artifact of a billion year
Speaker 3: old collision.
Speaker 2: Okay, what's the second theory? Because you said there.
Speaker 3: Were two, there's a second, perhaps even more violent theory,
Speaker 3: the ejection scenario objection. This theory suggests that the black
Speaker 3: hole wasn't passively left behind by a merger, but was
Speaker 3: actively violently thrown outward from the center of its own galaxy.
Speaker 2: Wait, thrown, yes, you throw a million suns. What could
Speaker 2: possibly generate enough force to eject a super massive black hole?
Speaker 3: Gravity itself, specifically, the chaotic gravitational interactions between multiple massive
Speaker 3: black holes near a galaxy.
Speaker 2: Center, multiple like more than two exactly.
Speaker 3: This often happens in the chaotic aftermath of not just one,
Speaker 3: but multiple successive galactic mergers. Imagine a scenario where three
Speaker 3: massive black holes end up drawn toward the center of
Speaker 3: a newly forming galaxy before they have a chance to merge.
Speaker 2: Okay, I could see where this is going. It's like
Speaker 2: a cosmic game of billiards, but the billiard balls weigh
Speaker 2: millions of solar masses.
Speaker 3: And this brings us to one of the most famously
Speaker 3: unsolvable concepts in astrophysics, the three body problem.
Speaker 2: Oh, I've heard of this. It's notorious.
Speaker 3: It is in classical mechanics. If you have two massive
Speaker 3: bodies orbiting each other, like the Earth and the Sun,
Speaker 3: or two black holes, their orbits are stable, predictable, and
Speaker 3: mathematically elegant.
Speaker 2: Right, it's a balanced equation. We can calculate where the
Speaker 2: Earth will be next year with perfect accuracy.
Speaker 3: We can calculate their positions billions of years into the future.
Speaker 3: But the moment you introduce a third massive body into
Speaker 3: that gravitational system, the mathematics completely breaks down.
Speaker 2: It just stops working.
Speaker 3: The system becomes inherently chaotic and unstable. There is no
Speaker 3: simple mathematical solution. The three black holes whip around each
Speaker 3: other faster and faster, exchanging orbital energy in totally unpredictable ways,
Speaker 3: because every.
Speaker 2: Time body A gets close to body B body C
Speaker 2: is pulling on them from a different angle, constantly changing
Speaker 2: the trajectories.
Speaker 3: Precisely, they are constantly stealing kinetic energy from one another.
Speaker 3: And in these unstable three body interactions, the inevitable outcome
Speaker 3: is almost always an injection.
Speaker 2: Something gets kicked out of the club.
Speaker 3: Always. The laws of conservation of energy and angular momentum
Speaker 3: basically demand a resolution to the chaos. The lightest of
Speaker 3: the three objects, or the one that simply hits the
Speaker 3: wrong angle at the wrong time in this complex dance,
Speaker 3: receives a massive sudden kick of kinetic energy.
Speaker 2: It's violently kicked off the billiard tabe.
Speaker 3: It is quite literally slang shotted outward. And this kick
Speaker 3: is so powerful it overcomes the immense escape velocity of
Speaker 3: the entire galactic center.
Speaker 2: That is mind boggling, Propelled.
Speaker 3: By the very gravitational forces that drew it inward in
Speaker 3: the first place, it is flung out into the galactic halo,
Speaker 3: destined to wander the suburbs forever.
Speaker 2: I really want you listening to this right now to
Speaker 2: just pause and sit with the sheer scale of time
Speaker 2: involved here.
Speaker 3: It's hard to wrap your head around.
Speaker 2: It really is, because whether this black hole was stranded
Speaker 2: by a slow motion merger or kicked out in a
Speaker 2: chaotic gravitational slang shot, these are events that happened millions,
Speaker 2: possibly billions of years ago, deep Pine right, Which means
Speaker 2: this giant, this entity, with the mass of a million suns,
Speaker 2: has just been silently, stealthily drifting through the dark for eons.
Speaker 3: For longer than the Earth has had complex life.
Speaker 2: Totally undetectable, emitting no light, just waiting for me millions
Speaker 2: of years. It waited until one single unlucky star finally
Speaker 2: crossed its path and brushed the edge of that pothole.
Speaker 3: It highlights the vast quiet patients of the universe, time
Speaker 3: scales that basically render human history irrelevant.
Speaker 2: But you know, a black hole waiting in the dark
Speaker 2: is only half the equation.
Speaker 3: Here, right. We still had to find it.
Speaker 2: Because for a billion years it was invisible, and frankly,
Speaker 2: if we had been looking, we wouldn't have seen it.
Speaker 2: Even when the star exploded, we almost missed it.
Speaker 3: We came very close to missing it.
Speaker 2: Finding this thing required us to actually overcome our own
Speaker 2: deeply ingrained blind spots. We had to fundamentally change how
Speaker 2: we look at the night sky. And that brings us
Speaker 2: to the methodology and kind of the unsung hero of
Speaker 2: this entire.
Speaker 3: Discovery, the actual mechanism by which we found a single
Speaker 3: flash of light thirty thousand light years away from where
Speaker 3: it was supposed to be.
Speaker 2: Because we didn't just stumble on this by having a
Speaker 2: guy look through an eyepiece at the exact right second.
Speaker 3: Those days are long gone.
Speaker 2: We found this using artificial intelligence, specifically an AI classification
Speaker 2: tool called disocters. Yes, and this tool was originally developed
Speaker 2: by Robert Stein at the University of Maryland and NASA Goddard, and.
Speaker 3: Its application here is a total masterclass in modern astronomical
Speaker 3: technique because it addresses a fundamental crisis in the field
Speaker 3: right now.
Speaker 2: A crisis, yes.
Speaker 3: But to understand why the AI is so necessary, we
Speaker 3: have to look at how akash anamar Laputti, who is
Speaker 3: a postdoctoral researcher in physics and astronomy at UNC Chapel Hill,
Speaker 3: how he actually utilized it.
Speaker 2: Okay, what did he do differently.
Speaker 3: He adapted this desk to score AI to scan enormous
Speaker 3: amounts of telescope data. But here is the critical innovation.
Speaker 3: He adapted it specifically to search for TDE candidates away
Speaker 3: from galaxy centers.
Speaker 2: Okay, stop, because this is the part that completely blew
Speaker 2: my mind when I first learned about this.
Speaker 3: It's a great twist.
Speaker 2: Are you telling me that because human scientists assume that
Speaker 2: massive black holes only lived in the center of galaxies,
Speaker 2: we literally programmed our own blind spots into our telescopes. Yes,
Speaker 2: like we were deliberately ignoring the outer edges because we
Speaker 2: thought we already knew nothing was there.
Speaker 3: That is essentially correct, and it is a fascinating look
Speaker 3: at the intersection of human bias and computational limits.
Speaker 2: How does that even happen?
Speaker 3: Well, in astronomy, you are dealing with an infinite sky
Speaker 3: and very limited computational resources. You have to prioritize where
Speaker 3: you look and how you filter the data.
Speaker 2: You can't look at everything all the time.
Speaker 3: Exactly. For nearly a century, the established theory, which was
Speaker 3: backed by almost every observation we had ever made. Mind you,
Speaker 3: dictated that supermassive black holes exist exclusively in galactic nuclei, so.
Speaker 2: It wasn't a crazy assumption. It was based on past
Speaker 2: data right.
Speaker 3: Therefore, when astronomers wrote the initial algorithms to sift through
Speaker 3: telescope data to find TDEs, they heavily weighted the galactic center.
Speaker 2: So they literally wrote code that said, if a flash
Speaker 2: of light happens far away from the center, ignore it.
Speaker 2: It's not a TDE.
Speaker 3: Functionally, yes, if a flash occurred in the outer suburbs
Speaker 3: of a galaxy, the algorithms were trained to classify it
Speaker 3: as a supernova or maybe a variable star, or perhaps
Speaker 3: just an observational error.
Speaker 2: Because supernova's happened everywhere.
Speaker 3: Supernova have it all over galaxies? Yes, but a TDE
Speaker 3: in the suburbs. It didn't fit the established model, so
Speaker 3: the system filtered it out as noise or mithcategorized it.
Speaker 3: We trained the machines to ignore the anomalies.
Speaker 2: We let our assumptions dictate our reality.
Speaker 3: We did.
Speaker 2: We told the computers don't look over there, there's nothing interesting.
Speaker 2: So we only found this wandering giant because we finally
Speaker 2: told the AI to remove our human assumptions.
Speaker 3: Precisely, akash Anumar Laputi stated it perfectly. By explicitly removing
Speaker 3: the constraint that these events only happened in the galactic center,
Speaker 3: the team was able to find a black hole that
Speaker 3: would have otherwise been completely missed by standard search parameter.
Speaker 2: Just looked at the raw data exactly.
Speaker 3: The AI, once unchained from that geographical bias, just looked
Speaker 3: at the physics. It analyzed the characteristics of the flash
Speaker 3: and flagged it regardless of the zip code it occurred in.
Speaker 2: Wait, how does an AI know the difference between a
Speaker 2: star exploding as a supernova in the suburbs and a
Speaker 2: star being shredded by a black hole in the suburbs.
Speaker 3: That's the real magic of it, because they're both.
Speaker 2: Just bright flashes of light in a telescope. Right, Hey,
Speaker 2: to me, a flash is a flash.
Speaker 3: That is where the power of modern machine learning really
Speaker 3: comes in. AI doesn't just see a flash of light.
Speaker 3: It analyzes the light curve and the spectral signature.
Speaker 2: Okay, a white curve.
Speaker 3: Ye.
Speaker 2: That means how the brightness changes over time?
Speaker 3: Yeah, exactly. When a star explodes as a supernova, it
Speaker 3: expands outward, it gets very bright, very quickly, and then
Speaker 3: it cools off in a very specific predictable mathematical curve.
Speaker 2: Okay, so it has a known fingerprint. Yes.
Speaker 3: Furthermore, the light from a supernova contains the chemical signatures
Speaker 3: of heavy elements synthesized in the explosion, things like iron, nickel, silicon.
Speaker 2: So what does a TD look like to an AI? Then?
Speaker 2: How is it different?
Speaker 3: A TD looks fundamentally different. Remember the accretion disc we
Speaker 3: talked about earlier.
Speaker 2: The swirling superheat plasma.
Speaker 3: Yes, that disc stays incredibly hot for a much longer
Speaker 3: time than a supernova. It emits massive amounts of ultraviolet
Speaker 3: light and X rays, far more than a typical exploding star.
Speaker 2: So it's hotter and stays hot longer.
Speaker 3: And spectrally, it often shows broad smeared emission lines of
Speaker 3: hydrogen and helium, which is literally the shredded atmosphere of
Speaker 3: the dead star moving at relativistic speeds around the black hole.
Speaker 2: Okay, So the AI is looking at millions of flashes,
Speaker 2: and it's analyzing the temperature, the cooling rate, the ultraviolet spikes,
Speaker 2: and the chemical fingerprints all in fractions of a second.
Speaker 3: Yes, it's doing all of that simultaneously. But this also
Speaker 3: brings up why we need AI to do this in
Speaker 3: the first place, rather than just having astronomers look at
Speaker 3: the light curves.
Speaker 2: Themselves, why couldn't a team of grad students just look
Speaker 2: at the graphs?
Speaker 3: Because it touches on the fundamental reality of modern science.
Speaker 3: We are deeply entrenched in the big data era of astronomy.
Speaker 2: Big data is almost an understatement here, isn't it?
Speaker 3: It is a massive understatement. Modern survey telescopes don't operate
Speaker 3: like the telescopes of the past, where you pointed at
Speaker 3: one specific galaxy, took a long exposure and developed a
Speaker 3: glass plate.
Speaker 2: Like the old man Palomar photos right.
Speaker 3: Today's survey telescopes continuously image vast swaths of the sky
Speaker 3: night after night after night. They generate terabytes, sometimes petabytes
Speaker 3: of raw data petabytes. They capture millions of transient events,
Speaker 3: things that flash, dim or move every single night.
Speaker 2: It's like trying to drink from a fire hose that
Speaker 2: is spraying the entire universe at you.
Speaker 3: The volume of information has far surpassed the capacity of
Speaker 3: human eyes. Even if you had teams of thousands of
Speaker 3: humans to process it, it wouldn't be enough.
Speaker 2: They just fall behind instantly.
Speaker 3: If a human tried to look at every single flash
Speaker 3: recorded by a modern telescope to determine if it was
Speaker 3: a TD, a supernova, a variable star, an asteroid, or
Speaker 3: just a reflection off a satellite. They would never finish
Speaker 3: a single night's data.
Speaker 2: So the AI isn't just a convene need helper anymore.
Speaker 3: Not at all. It is the fundamental, necessary lens through
Speaker 3: which we must filter the noise of the universe.
Speaker 2: The AI is doing the sifting. It's panning for gold
Speaker 2: in a river of raw data, looking for a flake
Speaker 2: of gold that we used to literally throw away because
Speaker 2: we didn't think gold belonged in that part of the river.
Speaker 3: It finds the impossible by tirelessly applying complex pattern recognition
Speaker 3: to data sets far too large for human comprehension. AI
Speaker 3: tools like discore are becoming the primary engines of discovery
Speaker 3: in chasing down these incredibly rare astronomical events.
Speaker 2: It's amazing.
Speaker 3: They remove the human computational bottleneck and critically they remove
Speaker 3: the human bias.
Speaker 2: So the AI looks at millions of data points, it
Speaker 2: sees this specific super hot UV heavy light signature thirty
Speaker 2: thousand light years off center in the Wiser galaxy, and
Speaker 2: it basically raises a digital hand and says, look at
Speaker 2: this es. But finding a candidate in a computer model
Speaker 2: is one thing, right, Proving it is real. Proving that
Speaker 2: a million mass monster actually just shredded a star in
Speaker 2: the outer rim of a galaxy that requires pointing physical
Speaker 2: glass at the sky.
Speaker 3: Absolutely, a flag in a database is just a hypothesis.
Speaker 3: It requires rigorous observational conformation. You need to gather the
Speaker 3: actual photons hitting the Earth.
Speaker 2: You need proof.
Speaker 3: This leads us to the critical ground game involved in
Speaker 3: this discovery. Once the AI flagged TDE twenty twenty five ABCR,
Speaker 3: the Carolina team needed rapid, high quality optical observation to
Speaker 3: confirm its nature before the flare faded back into.
Speaker 2: The dark, because it's not going to glow forever.
Speaker 3: No, it phades relatively quickly. And to do that follow
Speaker 3: up they use the SOR Telescope. The SOR telescope, yes,
Speaker 3: the Southern Astrophysical Research Telescope. It is located on Sarah Pachon,
Speaker 3: which is a mountain in the Chilean Andes.
Speaker 2: Chile is famous for its observatories.
Speaker 3: Right it boasts some of the clearest driest skies on Earth,
Speaker 3: perfect for astronomy. So R is a four point one
Speaker 3: meter optical and near infrared telescope, and it is highly
Speaker 3: relevant that UNC helped build s s and continues to
Speaker 3: operate it as part of an international consortium.
Speaker 2: Having your own four point one meter telescope on speed
Speaker 2: dial seems incredibly handy when you're hunting transient flashes in
Speaker 2: the dark.
Speaker 3: It is the difference between capturing an event and missing
Speaker 3: it entirely. Benjamin C. Kaiser, a postdoctoral researcher at UNC
Speaker 3: Chapel Hill, pointed out the immense value of.
Speaker 2: This facility because of the speed.
Speaker 3: When dealing with short lived astronomical phenomena like a TDE,
Speaker 3: time is of the essence the accretion disc will eventually
Speaker 3: be consumed, or it will cool down, the evidence will
Speaker 3: literally disappear.
Speaker 2: It's a ticking clock.
Speaker 3: Sor allowed the team to rapidly follow up on the
Speaker 3: AIS candidate, point a highly sensitive spectrograph at those exact
Speaker 3: coordinates and analyze the light to confirm definitively that this
Speaker 3: was indeed a massive black hole shredding a star.
Speaker 2: But this wasn't just checking a box to confirm what
Speaker 2: event was it. This specific optical confirmation is a monumental
Speaker 2: proof of concept for the entire field of astronomy.
Speaker 3: It truly is a milestone, which as have stated that
Speaker 3: TDE twenty twenty five ABCR provides the very first strong
Speaker 3: evidence that astronomers can reliably hunt for wandering supermassive black
Speaker 3: holes using ground based visible light telescopes.
Speaker 2: Let's make sure we underline why that is so important.
Speaker 2: Up until now, to find really weird extreme stuff like
Speaker 2: black holes, we often had to rely on space telescopes
Speaker 2: looking at X rays or gamma rays.
Speaker 3: R usually yes like the Chonder X ray observatory, and
Speaker 3: those space observatories are incredibly expensive, They have limited lifespans,
Speaker 3: and securing observation time on them is highly highly competitive.
Speaker 3: You basically have to win a lottery to get time
Speaker 3: on them.
Speaker 2: But this proves we can find these invisible monsters just
Speaker 2: by looking for the visible flash of their meals from
Speaker 2: right here on Earth using glass on a mountain in Chili.
Speaker 3: It effectively opens an entirely new sub field of astrophysics.
Speaker 3: It proves the methodology is sound. You combine unbiased AI
Speaker 3: scanning of large optical survey data with rapid follow up
Speaker 3: from agile ground based optical.
Speaker 2: Telescopes like SR one two punch.
Speaker 3: This combination is the blueprint for how we will map
Speaker 3: the hidden universe in the future.
Speaker 2: And that future is coming fast because that fire hose
Speaker 2: of data we were talking about earlier, it's about to
Speaker 2: turn into a complete ocean.
Speaker 3: We are standing on the precipice of an observational explosion.
Speaker 3: We have next generation survey telescopes coming online very soon
Speaker 3: that will absolutely dwarf for current capabilities.
Speaker 2: Give me some examples.
Speaker 3: Well, the NSF does Veric Reuben Observatory, which is currently
Speaker 3: being built in Chile, features a thirty two hundred megapixel camera.
Speaker 2: Thirty two hundred megapixels, that's absurd.
Speaker 3: It will essentially film a continuous high definition time lapse
Speaker 3: movie of the entire Southern sky every few nights. It
Speaker 3: will generate fifteen terabytes of data a night.
Speaker 2: Fifteen terabytes a night. Human eyes literally cannot look at that.
Speaker 3: It is physically impossible. We also have the Roman Space Telescope,
Speaker 3: which will survey vast areas of space with incredible infrared resolution.
Speaker 3: And UNC's own Argus Array, which is a uniquely designed
Speaker 3: telescope system meant to monitor the entire visible sky simultaneously
Speaker 3: for rapid transient events.
Speaker 2: So what does that transition look like for finding these things?
Speaker 2: If we've only found a little over one hundred TDEs
Speaker 2: in the past decade, what happens when Reuben and Roman
Speaker 2: and Argus actually turn.
Speaker 3: On The estimates are staggering. Astronomers expect to go from
Speaker 3: discovering tens of tidal disruption events per year in the
Speaker 3: relatively nearby universe to discovering many hundreds, if not thousands
Speaker 3: of them per year. Thousands, and at much greater cosmological distances.
Speaker 2: Thousands of stars being shredded by black holes spotted every
Speaker 2: single year.
Speaker 3: Which means we won't just be finding the standard centrally
Speaker 3: located black holes anymore. By applying the unbiased AI tools
Speaker 3: we just discussed to this massive new influx of data,
Speaker 3: we are bound to find countless more wandering black holes.
Speaker 2: Because we finally know how to look for them exactly.
Speaker 3: We will finally be able to map their populations, understand
Speaker 3: their distribution across galactic halos, and finally piece together the
Speaker 3: full chaotic history of galactic evilllution, of ancient mergers, and
Speaker 3: of three body slingshots.
Speaker 2: I want to connect this back to you listening right now.
Speaker 2: We've talked about billion year old galactic mergers, million mass
Speaker 2: ghosts hiding in the dark, AI algorithms rewriting their own biases,
Speaker 2: and giant pieces of glass on mountaintops in Chile.
Speaker 3: There's a lot of ground to cover.
Speaker 2: It's an incredible narrative of scale. But why should you
Speaker 2: care beyond just the sci fi cool factor of a
Speaker 2: rogue black hole eating a star? What is the actual
Speaker 2: relevance of this knowledge to humanity? Why does it matter
Speaker 2: to the physics of our own reality?
Speaker 3: It matters because it is a question of fundamental physics.
Speaker 3: These extreme events a supermassive black hole shredding a star
Speaker 3: release enormous amounts of energy energy we can't make here exactly.
Speaker 3: They create environments with gravitational forces, magnetic fields, and extreme
Speaker 3: states of matter that are absolutely fundamentally impossible to recreate
Speaker 3: in any laboratory on Earth.
Speaker 2: Right like, we can't build a black hole in a
Speaker 2: particle accelerator in Switzerland to see how space time bends.
Speaker 3: That would be ill advised even if we could.
Speaker 2: Very true, we can't compress matter into a singularity to
Speaker 2: see what happens to the laws of thermodynamics.
Speaker 3: Precisely, we cannot generate those magnetic fields, those temperatures, or
Speaker 3: that extreme space time curvature. Therefore, the universe itself must
Speaker 3: become our.
Speaker 2: Laboratory, the ultimate testing ground.
Speaker 3: Every time we observe a tde we are watching a
Speaker 3: fundamental physics experiment play out on a cosmic scale. By
Speaker 3: studying the light curves, the relativistic jets, the friction of
Speaker 3: the accretion disk, we are unraveling the bedrock laws that
Speaker 3: govern the entire universe.
Speaker 2: The same laws of physics that govern the atoms in
Speaker 2: your body right now, sitting in your car.
Speaker 3: Or walking your dog exactly, Gravity, electromagnetism, thermodynamics, These are
Speaker 3: the rules of the ecosystem we live inside. We are
Speaker 3: learning how gravity truly operates at its absolute extremes.
Speaker 2: Testing the limits of Einstein's theories.
Speaker 3: We are uncovering the full life cycles of stars and galaxies,
Speaker 3: the violence mechanisms of how structure forms in the universe.
Speaker 3: Every single observation brings us one step closer to understanding
Speaker 3: the mechanics of reality itself. We are not separate from
Speaker 3: these events. We are a byproduct of a universe dynamic
Speaker 3: enough to create them.
Speaker 2: It is awe inspiring to think about to recap the
Speaker 2: sheer scale of what we've just covered. We started with
Speaker 2: a single star drifting through a quiet galactic suburb, completely
Speaker 2: unaware that it was approaching a hazard it couldn't possibly.
Speaker 3: See, a cosmic ghost.
Speaker 2: We witnessed it splintering in the dark, pulled apart by
Speaker 2: tidal forces, illuminating a rogue one million solar mass black
Speaker 2: hole that had been violently exiled from its home millions
Speaker 2: or billions of years ago.
Speaker 3: And we saw how our own human assumptions almost hid
Speaker 3: it forever right.
Speaker 2: Our belief that monsters only hide in the center of
Speaker 2: the room almost kept this ghost hidden until we allowed
Speaker 2: an artificial intelligence to look at the data without our bias.
Speaker 2: We saw a telescope in Chile a pivot just in
Speaker 2: time to catch the fading light, proving that we can
Speaker 2: hunt these invisible anomalies from the ground.
Speaker 3: And we looked ahead to a very near future.
Speaker 2: A future where new massive observatories will soon find thousands
Speaker 2: of these violent cosmic meals, turning the night sky into
Speaker 2: the ultimate physics laboratory.
Speaker 3: It is a profound reminder that there is always more
Speaker 3: to learn, and that our understanding of the universe is
Speaker 3: constantly evolving. The cosmos is far more dynamic, chaotic, and
Speaker 3: beautifully violent than we often assume. But you know, there
Speaker 3: is one final piece of this puzzle, a final implication
Speaker 3: that I think we need to leave hanging in the air.
Speaker 2: Oh what's that?
Speaker 3: Think about the math for a second. Okay, If a
Speaker 3: single massive galaxy can hide a one million solar mass
Speaker 3: black hole roaming its outer edges, an entity completely invisible,
Speaker 3: entirely undetectable, drifting silently through the suburbs until the exact
Speaker 3: moment a random star bumps into it.
Speaker 2: Oh man, I see where this is going.
Speaker 3: How many other silent gravitational giants are wandering through the
Speaker 3: dark right now, perhaps even in our own galactic neighborhood,
Speaker 3: reshaping the universe in ways we cannot even see, just
Speaker 3: eating in the pitch black