WEBVTT

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<v Speaker 1>Welcome to Bedtime Astronomy. Explore the wonders of the cosmos

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<v Speaker 1>with our soothing Bedtime Astronomy podcast. Each episode offers a

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<v Speaker 1>gentle journey through the stars, planets, and beyond, perfect for

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<v Speaker 1>unwinding after a long day. Let's travel through the mysteries

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<v Speaker 1>of the universe as you drift off into a peaceful

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<v Speaker 1>slumber under the night sky.

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<v Speaker 2>I want you to imagine, just for a moment, that

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<v Speaker 2>you are tasked with assembling like a grand, sweeping family tree. Okay,

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<v Speaker 2>sounds fun, right, but this isn't human ancestry. You're mapping

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<v Speaker 2>out a cosmic family tree, tracing the lineage of the

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<v Speaker 2>most extreme gravity warping objects in the universe.

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<v Speaker 3>Oh, black holes.

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<v Speaker 2>Exactly black holes. And as you lay out all this data,

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<v Speaker 2>you hit a wall. You realize something profoundly weird, and

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<v Speaker 2>entire generation is completely missing. Yeah, a massive blank space, right, Like,

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<v Speaker 2>we can eat see the colossal ancient ancestors sitting at

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<v Speaker 2>the top of the chart, and we can clearly identify

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<v Speaker 2>the tiny, numerous descendants scattered all over the bottom. But

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<v Speaker 2>the middle generation it's just invisible.

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<v Speaker 3>It's completely absent, a.

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<v Speaker 2>Glaring blank space. You've probably heard of supermassive black holes.

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<v Speaker 2>You know those absolute monsters lurking at the center of galaxies,

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<v Speaker 2>and you almost certainly know about the smaller ones, the

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<v Speaker 2>stellar mass black holes formed from dying stars. But today

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<v Speaker 2>we're venturing out into the utter void of deep space

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<v Speaker 2>to find the missing middle.

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<v Speaker 3>We really are, and it's one of the most frustrating

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<v Speaker 3>yet mathematically tantalizing blind spots in modern astrophysics.

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<v Speaker 2>Tantalizing is a good word for it, because we're going

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<v Speaker 2>to look at how researchers are taking one of the

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<v Speaker 2>universe's greatest.

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<v Speaker 3>Mysteries, mass radio bursts.

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<v Speaker 2>Yeah, these fleeting, unexplained flashes of radio waves from deep space,

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<v Speaker 2>and they're essentially repurposing them as cosmic flashlights to expose

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<v Speaker 2>those elusive middleweight black holes.

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<v Speaker 3>It's wild because the fact that we have the extremes

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<v Speaker 3>perfectly documented, but the bridge between them has eluded us

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<v Speaker 3>for decades. It suggests that while either our theories of

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<v Speaker 3>how the universe grows are fundamentally flawed, or these objects

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<v Speaker 3>are hiding in a way we simply hadn't anticipated.

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<v Speaker 2>Right before we talk about how we're finally hunting them down,

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<v Speaker 2>let's establish why it's so strange that we can't find them.

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<v Speaker 2>Let's talk about these cosmic weaight.

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<v Speaker 3>Classes, good idea, because size dictates completely different physics here exactly.

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<v Speaker 2>So at the very top of the hierarchy, the undisputed heavyweights,

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<v Speaker 2>we have super massive black holes. These are the anchors, right.

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<v Speaker 3>Yeah, the anchors like Sagittarius, a star at the center

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<v Speaker 3>of our Milky.

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<v Speaker 2>Way, right, and virtually every other major galaxy has one. Yeah,

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<v Speaker 2>and we are talking about masses that are millions or

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<v Speaker 2>I mean even billions of times the mass of our Sun.

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<v Speaker 3>To give you a sense of scale, the black hole

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<v Speaker 3>at the center of the galaxy M eighty seven, which

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<v Speaker 3>was famously imaged a few years ago.

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<v Speaker 2>Oh, the glowing doughnut picture.

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<v Speaker 3>Yeah, the glowing orange ring. That one is about six

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<v Speaker 3>and a half billion times the mass of our Sun.

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<v Speaker 2>Billion with a bee.

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<v Speaker 3>With a b. These supermassive objects are the gravitational pivots

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<v Speaker 3>for entire galaxies. And you know, their origins are actually

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<v Speaker 3>still heavily.

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<v Speaker 2>Debated, really, like how they got so big.

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<v Speaker 3>Yeah, whether they started out as smaller seeds that merged

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<v Speaker 3>over billions of years, or if they collapsed directly from

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<v Speaker 3>massive clouds of gas in the early universe. But regardless

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<v Speaker 3>of how they got there, they are allowed.

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<v Speaker 2>Right. They aren't exactly hiding, not at all.

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<v Speaker 3>They're surrounded by accretion disks of superheated plasma that shine

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<v Speaker 3>brighter than the rest of the galaxy combined, so we

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<v Speaker 3>have no problem finding them.

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<v Speaker 2>Through the cosmic lighthouses. And then at the other end

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<v Speaker 2>of the observable spectrum, we have the lightweights, the stellar

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<v Speaker 2>mass black holes, the descendants. If we're keeping with a

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<v Speaker 2>family tree analogy. These are born when a massive star

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<v Speaker 2>reaches the end of its life, runs out of nuclear fuel,

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<v Speaker 2>and the core just collapses under its own staggering gravity.

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<v Speaker 3>Yeah, and these usually weigh in and that roughly five

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<v Speaker 3>to a few tens of times the mass of our Sun.

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<v Speaker 2>And the physics of stellar collapse, yeah, it puts a

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<v Speaker 2>natural cap on how big these can get, right.

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<v Speaker 3>It does. When a star is massive enough, the pressure

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<v Speaker 3>and temperature inside its core gets so incredibly high that

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<v Speaker 3>it actually triggers this phenomenon called pair instability.

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<v Speaker 2>Pair instability, what is that?

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<v Speaker 3>It's where photons literally particles of light, spontaneously turn into

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<v Speaker 3>electron positron pairs.

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<v Speaker 2>Wait, light just turns into matter.

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<v Speaker 3>Yeah, under those extreme conditions, and when that happens, it

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<v Speaker 3>causes a sudden drop in outward pressure, the star collapses,

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<v Speaker 3>and the resulting supernova completely obliterates the star, leaving absolutely

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<v Speaker 3>nothing behind, no black hole at all. Because of these mechanisms,

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<v Speaker 3>standard stellar evolution really struggles to produce black holes much

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<v Speaker 3>heavier than say, sixty to one hundred solar masses.

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<v Speaker 2>Okay, so I've got the supermassives and the stellar ones,

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<v Speaker 2>but just to put all our cards on the table,

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<v Speaker 2>there's also a theoretic featherweight class. Right, Yeah, primordial black holes.

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<v Speaker 3>Yes, primordial black holes. And these are distinct because they

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<v Speaker 3>weren't born from dying stars.

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<v Speaker 2>They predate stars entirely.

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<v Speaker 3>The theory goes that in the chaotic high energy environment

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<v Speaker 3>just fractions of a second after the Big Bang, the

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<v Speaker 3>universe wasn't perfectly smooth. It was a clumpy, right, There

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<v Speaker 3>were microscopic quantum fluctuations in some incredibly tiny regions. The

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<v Speaker 3>density of matter and radiation was so intensely concentrated that

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<v Speaker 3>it just collapsed directly into black holes.

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<v Speaker 2>Before atoms even existed.

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<v Speaker 3>Exactly, and depending on exactly when they formed in that

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<v Speaker 3>first split second, they could theoretically be the mass of

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<v Speaker 3>like an asteroid or a mountain, but squeeze down into

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<v Speaker 3>a space smaller than a single atom.

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<v Speaker 2>Okay, So we have the supermassive giants anchoring galaxies, the

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<v Speaker 2>skellar mass remnants scattered around, and potentially these tiny primordial

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<v Speaker 2>specks left over from the dawn of time. Right. But

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<v Speaker 2>then we look for the intermediate class, the middleweights, the

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<v Speaker 2>intermediate mass black holes, the missing link. Theoretically, these should

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<v Speaker 2>weigh somewhere between one hundred and one hundred that solar masses. Yeah,

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<v Speaker 2>but we look at into the universe and.

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<v Speaker 3>Well, nothing, nothing conclusive yet.

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<v Speaker 2>Like exploring the African savannah, right, and you find millions

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<v Speaker 2>of mice, and you find massive herds of elephants, but

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<v Speaker 2>you look around and realize there is absolutely zero evidence

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<v Speaker 2>of anything the size of a dog or a gazelle

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<v Speaker 2>or a horse.

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<v Speaker 3>That's a great analogy.

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<v Speaker 2>Are we just bad at looking or are the laws

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<v Speaker 2>of physics actively preventing them from forming?

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<v Speaker 3>Well, that is exactly the debate that has raged for years.

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<v Speaker 3>From a theoretical standpoint, they absolutely must exist.

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<v Speaker 2>Why must they.

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<v Speaker 3>Because the supermassive black holes we see in the early

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<v Speaker 3>universe are too big to have grown from stellar mass

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<v Speaker 3>black holes purely by eating surrounding gas.

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<v Speaker 2>The math doesn't work out right.

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<v Speaker 3>There simply hasn't been enough time since the Big Bang

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<v Speaker 3>for them to get that heavy. They had to have

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<v Speaker 3>merged from intermediate seeds.

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<v Speaker 2>Okay, so they have to be out there. Why can't

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<v Speaker 2>we see them?

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<v Speaker 3>Finding them isolated today is notoriously difficult because, unlike super

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<v Speaker 3>massive black holes that have entire galaxies of gas and

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<v Speaker 3>stars swirling around them, an isolated middleweight black hole wandering

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<v Speaker 3>through space doesn't have a glowing accretion disk.

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<v Speaker 2>So if it isn't eating, it isn't shining.

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<v Speaker 3>Exactly, if it isn't actively feeding on something, it emits

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<v Speaker 3>no light. It is a completely dark object against a

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<v Speaker 3>completely dark background.

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<v Speaker 2>But it's not just about filling in a blank on

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<v Speaker 2>a spreadsheet, is it. It's not just, oh, we need

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<v Speaker 2>to collect the middle one to finish the set. Why

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<v Speaker 2>do astrophysicists actually care so much about finding an object

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<v Speaker 2>in this specific.

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<v Speaker 3>Weight class because they represent a pristine environment to test

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<v Speaker 3>what physicists call strong field gravity.

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<v Speaker 2>Strong field gravity break that down for me. You mean

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<v Speaker 2>areas where gravity isn't just pulling a planet in an orbit,

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<v Speaker 2>but doing something fundamentally more aggressive.

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<v Speaker 3>Yeah, exactly. Think about the gravity we experience in our

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<v Speaker 3>Solar system. It's incredibly weak. Even the gravity of the Sun,

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<v Speaker 3>which keeps Earth in orbit, is considered weak. Feel in

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<v Speaker 3>the context of general relativity.

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<v Speaker 2>Really the Sun is weak.

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<v Speaker 3>Cosmologically speaking, yes, Newtonian physics can describe almost all of

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<v Speaker 3>it perfectly. But near the event horizon of a black hole,

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<v Speaker 3>space time is severely violently warped.

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<v Speaker 2>It gets weird, very weird.

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<v Speaker 3>It is stretched and twisted in ways that push Einstein's

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<v Speaker 3>equations to their absolute limits. Testing our theories of physics

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<v Speaker 3>and these extreme environments is crucial.

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<v Speaker 2>But couldn't we just test that on those super massive

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<v Speaker 2>black holes.

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<v Speaker 3>We try, but they are incredibly messy environments. They're filled

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<v Speaker 3>with magnetic fields, plasma jets, swirling matter, radiation.

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<v Speaker 2>It's too noisy.

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<v Speaker 3>Exactly, an isolated intermediate mass black hole would be a clean,

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<v Speaker 3>quiet laboratory, a pure distortion in space time without all

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<v Speaker 3>the astrophysical noise.

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<v Speaker 2>That makes a lot of sense. But the history of

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<v Speaker 2>trying to find these things is just a string of heartbreaks.

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<v Speaker 2>I mean, every time we think we have one it

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<v Speaker 2>slips away. Let's talk about the Omega Centauri controversy.

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<v Speaker 3>Oh yeah, the classic cautionary tale in this.

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<v Speaker 2>Field, because I think that perfectly illustrates how maddening this

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<v Speaker 2>search has been. So for context, if you aren't familiar

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<v Speaker 2>with Omegasentaury, it is the largest globular cluster in the

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<v Speaker 2>Milky Way galaxy.

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<v Speaker 3>It's huge.

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<v Speaker 2>It's this incredibly dense spherical collection of millions of ancient stars,

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<v Speaker 2>all packed tightly together, orbiting the center of our galaxy.

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<v Speaker 2>And back in two thousand and eight it made massive

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<v Speaker 2>headlines because it seemed like the missing link had finally

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<v Speaker 2>been found right in our cosmic backyard. I remember observations

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<v Speaker 2>from the Hubble Space telescope and the Gemini Observatory down

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<v Speaker 2>in Chile suggested that there was a massive, invisible object

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<v Speaker 2>sitting perfectly in the center of that star cluster.

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<v Speaker 3>Yeah. The researchers were looking at the kinematics of the cluster,

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<v Speaker 3>specifically how fast the stars right at the dense.

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<v Speaker 2>Core weremoving like bees swarming a hive.

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<v Speaker 3>Right By using the Doppler shift of the light from

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<v Speaker 3>those stars, they measured the velocity dispersion, and they found

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<v Speaker 3>that the stars near the center were whipping around much

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<v Speaker 3>faster than they should be based on the visible mass

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<v Speaker 3>of the stars alone.

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<v Speaker 2>So there's extra gravity coming from somewhere Exactly.

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<v Speaker 3>The gravitational math seemed inescapable. There had to be a

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<v Speaker 3>central concentrated mass of about forty thousand times the mass

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<v Speaker 3>of the Sun pulling on them.

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<v Speaker 2>Forty thousand so right in that intermediate sweet spot. Yep.

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<v Speaker 3>And since it emitted no light, it perfectly fit the

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<v Speaker 3>profile of an intermediate mass black hole.

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<v Speaker 2>I remember when that paper came out. It felt like

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<v Speaker 2>a slam dug. We found the missing link. But then

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<v Speaker 2>the scientific method showed up to ruin the party.

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<v Speaker 3>Well ruin or refined, depending on how you look at it. Enough,

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<v Speaker 3>the problem with looking into the center of a globular

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<v Speaker 3>cluster is that it is a dynamically complex, chaotic environment.

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<v Speaker 3>Follow up research heavily disputed those two thousand and eight claims.

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<v Speaker 2>Oh, so did they get the telescope data wrong?

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<v Speaker 3>No, the data was right. Other teams just build incredibly

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<v Speaker 3>complex n body simulations computer models that calculate the gravitational

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<v Speaker 3>interactions of millions of individual stars over billions of years.

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<v Speaker 2>Wait, so they didn't just disagree with the data, they

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<v Speaker 2>disagreed with what the data meant exactly.

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<v Speaker 3>The counter argument reposed a mechanism called mass segregation.

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<v Speaker 2>A mass segregation over.

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<v Speaker 3>Billions of years, the heavier objects in a star cluster

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<v Speaker 3>will naturally sink to the center due to gravitational friction,

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<v Speaker 3>while lighter stars get pushed.

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<v Speaker 2>Outward, like heavy rock sinking to the bottom of a river.

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<v Speaker 3>Yes, so what if that dark mass at the center

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<v Speaker 3>wasn't one single forty thousand solar mass black hole. What

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<v Speaker 3>if it was a swarm of a few thousand stellar

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<v Speaker 3>mass black holes, neutron stars and dead white dwarfs that

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<v Speaker 3>had all sunk to the core. Oh wow, they would

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<v Speaker 3>be invisible. They would collectively have enough mass to make

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<v Speaker 3>the other stars whip around quickly, and they wouldn't require

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<v Speaker 3>us to invent a new class of black hole to

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<v Speaker 3>explain them.

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<v Speaker 2>So the definitive proof basically just evaporated pretty much. Could

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<v Speaker 2>be one giant thing, or it could be a swarm

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<v Speaker 2>of small things. And from Earth it just looks the

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<v Speaker 2>same right as it stands now, just by decades of

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<v Speaker 2>staring into the heart of these dense star clusters, the

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<v Speaker 2>existence of intermediate mass black holes remains entirely unconfirmed.

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<v Speaker 3>We are zero for zero, which forces a paradigm shift.

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<v Speaker 3>If you can't find the invisible object by looking at

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<v Speaker 3>the stars swirling around it because the environment is just

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<v Speaker 3>too crowded and noisy, you have to find a completely

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<v Speaker 3>different method.

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<v Speaker 2>You have to look at what the black hole does

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<v Speaker 2>to light that just happens to be passing by it

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<v Speaker 2>from somewhere else exactly, And to do that you need

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<v Speaker 2>a very specific kind of light, a very specific probe,

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<v Speaker 2>which introduces the second massive mystery of our conversation. Fast

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<v Speaker 2>radio bursts.

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<v Speaker 3>Oh yeah, FRBs.

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<v Speaker 2>Now, if you are not an astrophysics nerd, you might

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<v Speaker 2>be thinking, okay, radio burst, what's the big deal? But

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<v Speaker 2>fast radio bursts or FRBs are the tools that astrophysicists

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<v Speaker 2>are now trying to use to find the missing black holes,

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<v Speaker 2>and they are wild, they really are. To understand how

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<v Speaker 2>this works, we need to talk about what an FRB

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<v Speaker 2>actually is, or rather what we observe them to be,

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<v Speaker 2>since we don't actually know what they are.

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<v Speaker 3>They are arguably the most active mystery astronomy today. I mean,

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<v Speaker 3>the first one was discovered purely by accident in two

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<v Speaker 3>thousand and seven.

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<v Speaker 2>Wait, by accident.

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<v Speaker 3>Yeah, it was retroactively found in archival data from the

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<v Speaker 3>Park's radio telescope. In Australia. It's often called the Lorimer burst,

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<v Speaker 3>named after the astronomer who found it.

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<v Speaker 2>And when we say fast, we really mean it, don't we. Oh?

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<v Speaker 3>Absolutely. These are transient pulses of radio emission and FRB

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<v Speaker 3>can last for as little as a tiny fraction of

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<v Speaker 3>a microsecond, maybe up to a few seconds on the

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<v Speaker 3>extreme long.

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<v Speaker 2>End, but most are over in the blink of an eye.

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<v Speaker 3>But it's not just their brevity that makes them astounding,

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<v Speaker 3>it's what that brevity implies about their power.

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<v Speaker 2>Right because they're coming from far away.

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<v Speaker 3>We know these bursts are coming from outside our galaxy,

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<v Speaker 3>and we know this because of a property called dispersion.

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<v Speaker 2>Dispersion Okay, how does that work?

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<v Speaker 3>As radio waves travel through the incredibly sparse cold plasma

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<v Speaker 3>in the inner galactic medium, the lower frequencies get slowed

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<v Speaker 3>down just a tiny tiny bit more than the higher.

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<v Speaker 2>Frequencies, like light passing through a prism.

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<v Speaker 3>Very similar. Yeah, so when the burst hits are telescopes,

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<v Speaker 3>the high frequencies arrive a fraction of a second before

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<v Speaker 3>the low frequencies. It smears out. By measuring that smear

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<v Speaker 3>that dispersion measure, we can calculate roughly how much space

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<v Speaker 3>the bursts traveled through.

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<v Speaker 2>And the dispersion measures for FRBs are.

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<v Speaker 3>Huge, massive. They tell us these flashes are traveling across

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<v Speaker 3>billions of light years of space. Now, just think about

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<v Speaker 3>the energy required for that, oh Man, for a signal

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<v Speaker 3>that lasts a fraction of a millisecond to be detectable

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<v Speaker 3>by our telescopes here on Earth, after radiating outward in

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<v Speaker 3>all directions and crossing billions of light years, I mean,

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<v Speaker 3>the source of that birds must be unimaginably powerful.

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<v Speaker 2>How powerful are we talking?

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<v Speaker 3>We are talking about an event that releases as much

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<v Speaker 3>energy in one millisecond as our sun emits in three days.

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<v Speaker 2>In one millisex. Yeah, okay, I have to stop and

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<v Speaker 2>push back on the logic of this entire endeavor right here.

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<v Speaker 2>Let me get this straight. We are trying to solve

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<v Speaker 2>the mystery of the missing intermediate black holes. Yes, to

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<v Speaker 2>do this, we're using another completely un mystery, these fast

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<v Speaker 2>radio bursts, as our primary tool. We are That feels

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<v Speaker 2>like trying to find a hidden object in a pitch

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<v Speaker 2>black room by using a flashlight, but you don't even

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<v Speaker 2>know how the flashlight works, who manufactured it, or who

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<v Speaker 2>is holding it. From a rigorous scientific standpoint, how is

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<v Speaker 2>that sound? How can you use an unknown to measure

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<v Speaker 2>an unknown?

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<v Speaker 3>It sounds like a paradox, I know, but it's actually

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<v Speaker 3>a deeply established tradition in physics. Really, Yeah, sometimes the

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<v Speaker 3>behavior of the probe is actually more important than its origin.

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<v Speaker 3>If we return to your dark room analogy, it genuinely

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<v Speaker 3>does not matter if you don't know the brand of

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<v Speaker 3>the flashlight, or what kind of batteries it uses, or

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<v Speaker 3>the chemical composition of the bulb. Okay, what matters is

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<v Speaker 3>that it is projecting a powerful, incredibly sharp, clean beam

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<v Speaker 3>of light straight across the room.

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<v Speaker 2>Ah, Because whatever that beam of light hits or passes

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<v Speaker 2>through is going to alter the beam, and we can

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<v Speaker 2>measure the alteration even if we don't know the source precisely.

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<v Speaker 3>Even if we don't know if an FRB is created

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<v Speaker 3>by a highly magnetized neutron star, a colliding binary system,

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<v Speaker 3>or something completely beyond our current physics, we know its

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<v Speaker 3>properties as it travels.

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<v Speaker 2>We know it's a straight line of radio waves, right.

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<v Speaker 3>We know it acts almost exactly like a point source

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<v Speaker 3>of light. We know it emits a sharp, coherent burst

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<v Speaker 3>of radio waves crossing vast cosmic distances. That makes it

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<v Speaker 3>a perfect naturally occurring backlight for whatever it bumps into

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<v Speaker 3>along its journey to Earth.

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<v Speaker 2>It's an ideal tool for eliminating the invisible obstacles in

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<v Speaker 2>the deep universe. Exactly, Okay, So let's put the two

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<v Speaker 2>pieces together. What exactly happens when this mysterious microsecond flash

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<v Speaker 2>of radio waves bumps into an invisible middleweight black hole.

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<v Speaker 2>It isn't like shining a flashlight at a brick wall

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<v Speaker 2>where the light just stops or reflex right. Gravity does

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<v Speaker 2>something far stranger, much strang It creates a very specific

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<v Speaker 2>kind of cosmic optical illusion. And this brings us to

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<v Speaker 2>the core mechanism of the whole search. Gravitational microlensing.

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<v Speaker 3>This is where that severe warping of space time you

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<v Speaker 3>mentioned earlier comes into.

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<v Speaker 2>Play, right the strong field gravity.

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<v Speaker 3>Yes, gravitational microlensing is a direct observable consequence of Einstein's

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<v Speaker 3>theory of general relativity. Mass bends space. John Archibald Wheeler

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<v Speaker 3>famously summarized it. Space time tells matter how to move.

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<v Speaker 3>Matter tells space time how to curve.

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<v Speaker 2>I love that quote, it's perfect.

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<v Speaker 3>But the thing is space time also tells light how

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<v Speaker 3>to move.

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<v Speaker 2>Let me try to visualize this. Let's say a galaxy

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<v Speaker 2>three billion light years away fires off a fast radio burst.

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<v Speaker 2>That little package of radioways starts traveling in a perfectly

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<v Speaker 2>straight line toward Earth. But directly in its path, lurking

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<v Speaker 2>completely unseen in the darkness of intergalactic space, is an

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<v Speaker 2>intermediate mass black hole. As that FRB gets close to

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<v Speaker 2>the black hole, it doesn't just fly straight past it, right, Yeah,

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<v Speaker 2>Because the space around the black hole isn't flat exactly.

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<v Speaker 3>The black hole is acting as what we call a

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<v Speaker 3>point mass lens. Its extreme gravity has created a deep,

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<v Speaker 3>a severe geometric curve in the very fabric of space.

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<v Speaker 2>Time around it, like a bowling ball on a trampoline.

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<v Speaker 3>Yes, the classic analogy. It's not that the light is

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<v Speaker 3>being pulled by gravity the way a planet is. Rather,

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<v Speaker 3>the light is always traveling in a straight line, but

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<v Speaker 3>the space itself.

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<v Speaker 2>Is curved, so the straight line becomes a curve.

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<v Speaker 3>Right, So when the effrob enters that warped region, the

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<v Speaker 3>path of the light is forced to follow the curve.

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<v Speaker 3>Of space bending around the black hole.

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<v Speaker 2>Okay, let's say I'm looking at a candle on a

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<v Speaker 2>table and I place let's see, not a funhouse marre,

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<v Speaker 2>that just scatters things. What if I place a thick,

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<v Speaker 2>curved piece of glass right in front of the candle,

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<v Speaker 2>like the base of a thick wine goblet. Okay, yeah,

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<v Speaker 2>the curved glass physically bends the light rays from the candle.

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<v Speaker 2>So when the light finally reaches my eye, my brain,

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<v Speaker 2>which assumes light travels in straight lines, traces those bent

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<v Speaker 2>rays backwards and sees two distinct candle flames instead of one.

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<v Speaker 2>That's spot on. In our cosmic scenario, the black hole

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<v Speaker 2>is the base of the wine glass bending the radio burst.

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<v Speaker 3>That is a phenomenal way to picture it. The gravity

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<v Speaker 3>of the black hole forces the light to take two

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<v Speaker 3>separate paths around it to reach us. But here is

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<v Speaker 3>what's crucial for the researchers. How does this bending actually

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<v Speaker 3>look to our telescopes when we analyze the data.

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<v Speaker 2>Because we can't actually see two flashes of light right now.

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<v Speaker 3>No, we don't have telescopes with the spatial resolution to

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<v Speaker 3>actually see two separate flashes of light in the sky.

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<v Speaker 3>The angular separation is incredibly tiny on the scale of

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<v Speaker 3>milliarc seconds or less.

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<v Speaker 2>Right, because an FRB is so far away, it's just

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<v Speaker 2>a single pixel of data hitting our radio dish. So

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<v Speaker 2>how do we know it was split time?

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00:19:39.119 --> 00:19:41.720
<v Speaker 3>The speed of light is absolute. If an FRB travels

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<v Speaker 3>through empty space, our telescopes record a single sharp spike

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00:19:45.319 --> 00:19:47.920
<v Speaker 3>of rato waves, a single peak on the graph. Okay,

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00:19:48.000 --> 00:19:50.119
<v Speaker 3>but if that FRB has been micro lensed by a

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00:19:50.119 --> 00:19:52.480
<v Speaker 3>black hole, it took two different paths to get here,

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00:19:52.920 --> 00:19:55.759
<v Speaker 3>and in the geometry of curved space, those two paths

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00:19:55.799 --> 00:19:57.920
<v Speaker 3>are almost certainly not the exact same.

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<v Speaker 2>Length, So one path is longer than the other, exactly.

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00:20:01.079 --> 00:20:05.400
<v Speaker 3>Furthermore, the light traveling closer to the black hole experiences

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<v Speaker 3>a deeper gravitational well, causing what's known as the Shapiro

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<v Speaker 3>time delay.

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<v Speaker 2>The Shapiro time delay, what's that.

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<v Speaker 3>It means time itself moves slightly slower in a stronger

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<v Speaker 3>gravitational field relative to the observer.

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<v Speaker 2>Oh wow, So you have the physical path being longer

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00:20:21.640 --> 00:20:24.640
<v Speaker 2>and the local time for the light ray literally slowing down.

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00:20:24.759 --> 00:20:28.319
<v Speaker 3>Yes, exactly, So one path takes a tiny fraction of

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<v Speaker 3>a millisecond longer to reach Earth than the other path.

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<v Speaker 3>The single burst of radio waves arrives at our telescopes

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<v Speaker 3>at two slightly.

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00:20:35.359 --> 00:20:36.880
<v Speaker 2>Different times, Like an echo.

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<v Speaker 3>It appears on our readouts as a clear multipeak structure,

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00:20:40.720 --> 00:20:45.279
<v Speaker 3>one burst superimposed with its own echo, arriving mere milliseconds apart.

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<v Speaker 2>Wait, if I'm tracking the physics here, this isn't just

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<v Speaker 2>a need visual trick. This is essentially a scale. Isn't

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00:20:50.160 --> 00:20:53.000
<v Speaker 2>it a mathematical scale to weigh the invisible object?

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00:20:53.079 --> 00:20:55.440
<v Speaker 3>It is exactly a scale. The time delay between those

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00:20:55.480 --> 00:20:58.240
<v Speaker 3>two peaks, that split second difference in their arrival is

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<v Speaker 3>directly mathematically to determined by the mass of the object

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<v Speaker 3>that bent the light.

430
00:21:02.920 --> 00:21:04.519
<v Speaker 2>Really just from the delay yep.

431
00:21:04.960 --> 00:21:07.960
<v Speaker 3>The heavier the black hole, the deeper the space time curve,

432
00:21:08.319 --> 00:21:11.119
<v Speaker 3>the wider the paths diverge, and the longer the delay

433
00:21:11.160 --> 00:21:14.200
<v Speaker 3>between the original pulse and the echo that is wild.

434
00:21:14.480 --> 00:21:17.880
<v Speaker 3>By measuring that tiny delay between the echoes, physicists can

435
00:21:17.920 --> 00:21:21.279
<v Speaker 3>work backward through the equations of general relativity and calculate

436
00:21:21.319 --> 00:21:23.680
<v Speaker 3>the exact mass of the invisible lens.

437
00:21:23.799 --> 00:21:27.160
<v Speaker 2>That is breathtaking, which means if we find the right

438
00:21:27.240 --> 00:21:29.440
<v Speaker 2>kind of echo hidden in the data of a fast

439
00:21:29.559 --> 00:21:33.799
<v Speaker 2>radio burst, we can precisely weigh an invisible black hole

440
00:21:34.119 --> 00:21:37.079
<v Speaker 2>that is billions of light years away and completely dark.

441
00:21:37.200 --> 00:21:39.720
<v Speaker 3>That is the theory, yes, and it is an elegant

442
00:21:39.759 --> 00:21:42.599
<v Speaker 3>application of physics. But until recently it was just a theory.

443
00:21:43.000 --> 00:21:45.720
<v Speaker 3>We simply didn't have enough high resolution data on fast

444
00:21:45.759 --> 00:21:48.519
<v Speaker 3>radio bursts to search for these microsecond echoes.

445
00:21:48.559 --> 00:21:51.000
<v Speaker 2>And this is where the groundbreaking new research comes in.

446
00:21:51.079 --> 00:21:54.119
<v Speaker 2>This is where theory hits reality. A team led by

447
00:21:54.200 --> 00:21:57.279
<v Speaker 2>Juanzou at the School of Physics and opto Electronic Engineering

448
00:21:57.279 --> 00:22:01.039
<v Speaker 2>at Yang's University recently put this exact method to the test.

449
00:22:01.160 --> 00:22:03.839
<v Speaker 2>They did they didn't just write another theoretical paper. They

450
00:22:03.839 --> 00:22:08.039
<v Speaker 2>went hunting. They dove into a massive database called the

451
00:22:08.079 --> 00:22:14.359
<v Speaker 2>Canadian Hydrogen Intensity Mapping Experiment or CHIME, specifically the Chia

452
00:22:14.440 --> 00:22:18.039
<v Speaker 2>Chime FRB catalog too. Now I want to talk about

453
00:22:18.079 --> 00:22:20.319
<v Speaker 2>CHIME for a second, because it is not what you

454
00:22:20.359 --> 00:22:21.720
<v Speaker 2>picture when you think of a telescope.

455
00:22:21.839 --> 00:22:25.279
<v Speaker 3>No, not at all. If you picture a giant steerable

456
00:22:25.319 --> 00:22:29.160
<v Speaker 3>satellite dish pointing at the sky, you have the completely wrong.

457
00:22:29.039 --> 00:22:30.640
<v Speaker 2>Image like the one in context.

458
00:22:30.359 --> 00:22:33.880
<v Speaker 3>Ya exactly, the RCIBO kind of dish. Chime isn't like that.

459
00:22:33.960 --> 00:22:37.319
<v Speaker 3>It looks more like a series of four massive snowboarding

460
00:22:37.400 --> 00:22:39.559
<v Speaker 3>half pipes sitting out in a valley in.

461
00:22:39.480 --> 00:22:41.279
<v Speaker 2>British Columbia, the Barding half pipes.

462
00:22:41.559 --> 00:22:45.920
<v Speaker 3>It consists of four cylindrical parabolic reflectors, each one hundred

463
00:22:45.960 --> 00:22:48.400
<v Speaker 3>meters long, with no moving parts whatsoever.

464
00:22:48.519 --> 00:22:50.000
<v Speaker 2>It just stares straight up right.

465
00:22:50.039 --> 00:22:52.119
<v Speaker 3>It relies on the rotation of the Earth to sweep

466
00:22:52.119 --> 00:22:55.599
<v Speaker 3>the sky. But what makes it so revolutionary is its

467
00:22:55.640 --> 00:22:59.880
<v Speaker 3>digital back end. It uses an incredibly powerful supercomputer core

468
00:23:00.119 --> 00:23:03.799
<v Speaker 3>later to process massive amounts of radio data in real times.

469
00:23:03.839 --> 00:23:05.920
<v Speaker 2>It was more computer than telescope.

470
00:23:05.519 --> 00:23:09.319
<v Speaker 3>In many ways. Yes, it essentially forms thousands of digital

471
00:23:09.359 --> 00:23:12.960
<v Speaker 3>beams to monitor a huge swath of the sky simultaneously.

472
00:23:13.599 --> 00:23:17.079
<v Speaker 3>Because FRBs can appear anywhere at any time without warning,

473
00:23:17.519 --> 00:23:20.079
<v Speaker 3>you need a telescope with a massive field of view.

474
00:23:20.160 --> 00:23:22.240
<v Speaker 2>You can't just point a small telescope and hope one

475
00:23:22.279 --> 00:23:23.240
<v Speaker 2>happens exactly.

476
00:23:23.680 --> 00:23:26.960
<v Speaker 3>C Chia is essentially the ultimate wide angle lens for

477
00:23:27.079 --> 00:23:31.319
<v Speaker 3>transient radio signals. It has completely transformed the field, building

478
00:23:31.319 --> 00:23:34.559
<v Speaker 3>a comprehensive catalog of hundreds of these fleeting bursts.

479
00:23:34.880 --> 00:23:37.519
<v Speaker 2>It is a treasure trope of data for researchers looking

480
00:23:37.559 --> 00:23:43.160
<v Speaker 2>for anomalies. So Hanzu's team analyzed this vast catalog, searching

481
00:23:43.200 --> 00:23:47.720
<v Speaker 2>specifically for FRBs that exhibited that clear multipeak structure, the

482
00:23:47.759 --> 00:23:50.920
<v Speaker 2>telltale echo of gravitational microlensing.

483
00:23:50.400 --> 00:23:52.279
<v Speaker 3>And they were incredibly thorough right.

484
00:23:52.279 --> 00:23:55.559
<v Speaker 2>They meticulously ruled out bursts where the multipeak structure could

485
00:23:55.559 --> 00:23:58.000
<v Speaker 2>be caused by noise in the data or known scattering

486
00:23:58.000 --> 00:24:01.000
<v Speaker 2>effects from interstellar gas. At all the data, they found

487
00:24:01.039 --> 00:24:04.680
<v Speaker 2>two very specific microlensing signatures that stood out.

488
00:24:04.519 --> 00:24:07.279
<v Speaker 3>And this is where the rigorous mathematical modeling pays off.

489
00:24:07.640 --> 00:24:10.799
<v Speaker 3>When they applied those general relativity lensing equations to the

490
00:24:10.839 --> 00:24:14.680
<v Speaker 3>precise time delays of those specific echoes, the numbers they

491
00:24:14.759 --> 00:24:16.319
<v Speaker 3>got were extraordinary.

492
00:24:16.519 --> 00:24:19.519
<v Speaker 2>The moment of truth, they calculated the mass of the

493
00:24:19.559 --> 00:24:23.720
<v Speaker 2>invisible lenses that caused those two echoes. For the first signature,

494
00:24:23.759 --> 00:24:27.400
<v Speaker 2>the mathematics inferred a mass somewhere between five hundred and

495
00:24:27.440 --> 00:24:30.240
<v Speaker 2>thirty nine and six hundred and nine times the mass

496
00:24:30.240 --> 00:24:33.960
<v Speaker 2>of our Sun. Incredible, And for the second signature, the

497
00:24:34.039 --> 00:24:36.920
<v Speaker 2>inferred mass was between one thousand, five hundred and forty

498
00:24:36.960 --> 00:24:40.440
<v Speaker 2>four and two thousand, five hundred and seventy one solar masses.

499
00:24:40.519 --> 00:24:43.559
<v Speaker 3>Both of those specific ranges around six hundred solar masses

500
00:24:43.559 --> 00:24:47.640
<v Speaker 3>and around two thousand solar masses. They sit perfectly squarely

501
00:24:47.799 --> 00:24:50.839
<v Speaker 3>within that elusive intermediate mass black hole gap.

502
00:24:50.960 --> 00:24:53.079
<v Speaker 2>They fit right in the blank space on the family tree.

503
00:24:53.160 --> 00:24:55.599
<v Speaker 3>Yes, they're far too heavy to be stellar mass black

504
00:24:55.640 --> 00:24:58.039
<v Speaker 3>holes and far too light to be super massive black hole.

505
00:24:58.079 --> 00:25:00.160
<v Speaker 2>Okay, but let's play Devil's advocate here. Let's say I'm

506
00:25:00.160 --> 00:25:02.720
<v Speaker 2>an astrophysicist reading this paper, and I want to be

507
00:25:02.799 --> 00:25:05.480
<v Speaker 2>as skeptical as possible. Please, do we found something heavy

508
00:25:05.480 --> 00:25:08.839
<v Speaker 2>that bends light? We know what weighs, say two thousand

509
00:25:08.880 --> 00:25:11.559
<v Speaker 2>times the mass of the Sun, But how do we

510
00:25:11.599 --> 00:25:14.359
<v Speaker 2>know it's a black hole? Space is full of stuff.

511
00:25:15.039 --> 00:25:17.440
<v Speaker 2>How do we know the light wasn't bent by a

512
00:25:17.480 --> 00:25:21.000
<v Speaker 2>really dense dark cloud of gas or maybe a really

513
00:25:21.559 --> 00:25:25.519
<v Speaker 2>tight ancient cluster of dead stars like what they thought

514
00:25:25.559 --> 00:25:26.759
<v Speaker 2>was happening in omegasentury.

515
00:25:26.960 --> 00:25:29.400
<v Speaker 3>It's the essential question, and the answer lies in the

516
00:25:29.440 --> 00:25:33.240
<v Speaker 3>specific constraints of the point mass lens geometry. To bend

517
00:25:33.359 --> 00:25:38.079
<v Speaker 3>light in this very clean, specific way, to create that distinct, sharp,

518
00:25:38.240 --> 00:25:42.160
<v Speaker 3>unscattered multipeak structure from a coherent radio burst, the echo

519
00:25:42.240 --> 00:25:44.640
<v Speaker 3>the echo right the mass doing the bending must be

520
00:25:44.720 --> 00:25:48.240
<v Speaker 3>unimaginably compact, the physical size of the lens has to

521
00:25:48.279 --> 00:25:50.319
<v Speaker 3>be smaller than the Einstein ring radius.

522
00:25:50.359 --> 00:25:53.680
<v Speaker 2>It creates the Einstein ring radius, meaning the physical spread

523
00:25:53.720 --> 00:25:54.960
<v Speaker 2>of the bent light exactly.

524
00:25:55.160 --> 00:25:57.759
<v Speaker 3>If the object doing the bending is physically wider than

525
00:25:57.759 --> 00:25:59.720
<v Speaker 3>the paths the light ticks around it. The light just

526
00:25:59.759 --> 00:26:03.240
<v Speaker 3>hits the object or passes through the object and get scattered, absorbed,

527
00:26:03.279 --> 00:26:05.759
<v Speaker 3>or smeared out. It doesn't create a clean echo.

528
00:26:06.079 --> 00:26:07.799
<v Speaker 2>So a gas cloud wouldn't work.

529
00:26:07.839 --> 00:26:10.799
<v Speaker 3>Not even close. A cloud of gas weighing two thousand

530
00:26:10.920 --> 00:26:13.720
<v Speaker 3>solar masses would be diffuse. It would be spread out

531
00:26:13.759 --> 00:26:16.279
<v Speaker 3>over light years. It wouldn't ben the light sharply like

532
00:26:16.319 --> 00:26:17.559
<v Speaker 3>the base of a wineglass.

533
00:26:17.559 --> 00:26:19.119
<v Speaker 2>You could just be fog exactly.

534
00:26:19.559 --> 00:26:21.599
<v Speaker 3>The radio bursts would pass through it, and the free

535
00:26:21.599 --> 00:26:24.839
<v Speaker 3>electrons in the gas would smear the signal entirely, changing

536
00:26:24.880 --> 00:26:27.519
<v Speaker 3>its dispersion measure in ways we could easily identify.

537
00:26:27.680 --> 00:26:29.640
<v Speaker 2>And what about a tight cluster of dead stars?

538
00:26:30.440 --> 00:26:33.359
<v Speaker 3>Even if you packed thousands of white dwarfs and neutron

539
00:26:33.440 --> 00:26:36.559
<v Speaker 3>stars together as tightly as physically possible without the merging,

540
00:26:37.119 --> 00:26:40.160
<v Speaker 3>cluster of two thousand solar masses would still be far

541
00:26:40.200 --> 00:26:43.720
<v Speaker 3>too physically large. Plus an environment that dense would be

542
00:26:43.759 --> 00:26:44.759
<v Speaker 3>incredibly violent.

543
00:26:45.000 --> 00:26:45.880
<v Speaker 2>Lots of collisions.

544
00:26:46.000 --> 00:26:49.599
<v Speaker 3>Stars would collide, accrete matter, and emit their own ambient light,

545
00:26:49.920 --> 00:26:53.880
<v Speaker 3>X rays or thermal radiation. We would detect that surrounding.

546
00:26:53.440 --> 00:26:56.079
<v Speaker 2>Noise, but the data shows nothing.

547
00:26:55.880 --> 00:26:58.799
<v Speaker 3>Nothing at all. These lenses are completely dark and their

548
00:26:58.799 --> 00:27:03.160
<v Speaker 3>gravitational focus is razor sharp at these specific mass ranges.

549
00:27:03.359 --> 00:27:07.640
<v Speaker 3>Physics dictates that an object this massive, this physically compact,

550
00:27:07.759 --> 00:27:11.920
<v Speaker 3>and this completely electromagnetically silent, can really.

551
00:27:11.599 --> 00:27:13.400
<v Speaker 2>Only be one thing, a black hole.

552
00:27:13.640 --> 00:27:16.000
<v Speaker 3>The matter has to be crushed down below its own

553
00:27:16.079 --> 00:27:18.200
<v Speaker 3>Schwartz Child radius. It has to be a black hole.

554
00:27:18.319 --> 00:27:22.400
<v Speaker 2>That is staggering. Finding these specific masses, actually weighing these

555
00:27:22.480 --> 00:27:25.480
<v Speaker 2>objects and seeing they fit the missing Middleway profile is

556
00:27:25.519 --> 00:27:28.200
<v Speaker 2>a monumental achievement on its own. It feels like we

557
00:27:28.559 --> 00:27:32.000
<v Speaker 2>finally have our first real tangible map to the missing

558
00:27:32.039 --> 00:27:33.519
<v Speaker 2>generation we talked about at the beginning.

559
00:27:33.559 --> 00:27:34.920
<v Speaker 3>That's a huge milestone.

560
00:27:34.960 --> 00:27:37.440
<v Speaker 2>But here is where the research takes a massive turn.

561
00:27:37.839 --> 00:27:41.839
<v Speaker 2>The researchers realized that where these objects are located might

562
00:27:41.880 --> 00:27:45.480
<v Speaker 2>actually be an even bigger discovery than their mass. The

563
00:27:45.519 --> 00:27:49.480
<v Speaker 2>spatial context of these two detections might literally rewrite our

564
00:27:49.559 --> 00:27:51.119
<v Speaker 2>understanding of the early universe.

565
00:27:51.319 --> 00:27:54.519
<v Speaker 3>Yes, the location factor here ships the paper from a

566
00:27:54.559 --> 00:27:59.799
<v Speaker 3>great astrophysics discovery into profound cosmological territory because when the

567
00:28:00.000 --> 00:28:02.880
<v Speaker 3>scheme analyzed the line of sight, meaning they calculated the

568
00:28:02.920 --> 00:28:05.680
<v Speaker 3>direct path from the origin galaxy of the fast radio

569
00:28:05.720 --> 00:28:08.640
<v Speaker 3>burst through the invisible lens all the way to the

570
00:28:08.640 --> 00:28:12.480
<v Speaker 3>Shei telescope on Earth, they realize something profoundly strange about

571
00:28:12.519 --> 00:28:14.440
<v Speaker 3>the environment surrounding these black holes.

572
00:28:14.839 --> 00:28:18.200
<v Speaker 2>Right, Usually black holes are anchored in galaxies or at

573
00:28:18.279 --> 00:28:21.440
<v Speaker 2>least dense star clusters. They're born in stellar nurseries. They

574
00:28:21.440 --> 00:28:24.160
<v Speaker 2>live in galactic disks. They are surrounded by matter.

575
00:28:24.319 --> 00:28:25.200
<v Speaker 3>Yeah, they have neighbors.

576
00:28:25.400 --> 00:28:28.680
<v Speaker 2>But in the case of these two specific microlensing signatures,

577
00:28:29.079 --> 00:28:32.440
<v Speaker 2>there are no intervening structures. There are no galaxies, no

578
00:28:32.559 --> 00:28:36.400
<v Speaker 2>galaxy clusters, no vast webs of visible matter along the

579
00:28:36.440 --> 00:28:39.640
<v Speaker 2>line of sight in the immediate vicinity of the lens, which.

580
00:28:39.519 --> 00:28:44.039
<v Speaker 3>Leads to a startling, almost eerie conclusion. These black holes

581
00:28:44.039 --> 00:28:48.079
<v Speaker 3>appear to be completely isolated. They are drifting completely alone

582
00:28:48.200 --> 00:28:51.559
<v Speaker 3>in the vast empty intergalactic voids of deep space.

583
00:28:51.839 --> 00:28:53.880
<v Speaker 2>So if you're trying to figure out why this matters,

584
00:28:54.200 --> 00:28:57.519
<v Speaker 2>think about the origin story. If an intermediate mass black

585
00:28:57.559 --> 00:29:00.480
<v Speaker 2>hole isn't inside a galaxy, and there is no evidence

586
00:29:00.519 --> 00:29:03.279
<v Speaker 2>it was ever part of a star cluster. How did

587
00:29:03.319 --> 00:29:03.839
<v Speaker 2>it get there?

588
00:29:04.160 --> 00:29:08.079
<v Speaker 3>It challenges the standard models fundamentally. If it's isolated and

589
00:29:08.119 --> 00:29:10.240
<v Speaker 3>avoid it couldn't have been born from a dying star

590
00:29:10.319 --> 00:29:13.559
<v Speaker 3>because stars don't form in intergalactic voids. They need dense

591
00:29:13.680 --> 00:29:15.400
<v Speaker 3>clouds of gas to ignite.

592
00:29:15.200 --> 00:29:16.119
<v Speaker 2>Right, they need a nursery.

593
00:29:16.319 --> 00:29:19.119
<v Speaker 3>And it couldn't have formed from a runaway collision of

594
00:29:19.200 --> 00:29:22.160
<v Speaker 3>stars in a dense cluster because there is no cluster.

595
00:29:23.000 --> 00:29:26.759
<v Speaker 3>The environment necessary for that kind of stellar evolution simply

596
00:29:26.880 --> 00:29:29.960
<v Speaker 3>is are there, And it's highly improbable that a two

597
00:29:30.079 --> 00:29:34.119
<v Speaker 3>thousand solar mass black hole was somehow ejected from a

598
00:29:34.160 --> 00:29:37.440
<v Speaker 3>galaxy without taking any stars with it or leaving a

599
00:29:37.519 --> 00:29:40.200
<v Speaker 3>massive gravitational wake we could detect.

600
00:29:39.880 --> 00:29:42.920
<v Speaker 2>Which brings us right back to the theoretical featherweights we mentioned

601
00:29:42.960 --> 00:29:45.640
<v Speaker 2>at the very beginning in the show, but scaled up

602
00:29:46.279 --> 00:29:48.440
<v Speaker 2>primordial black holes exactly.

603
00:29:49.000 --> 00:29:52.079
<v Speaker 3>This is why the researchers explicitly suggest these candidates are

604
00:29:52.119 --> 00:29:55.000
<v Speaker 3>strongly pointing toward a primordial origin.

605
00:29:54.720 --> 00:29:56.680
<v Speaker 2>Because they formed before anything else.

606
00:29:56.920 --> 00:29:59.720
<v Speaker 3>Right, Because primordial black holes formed just a fraction of

607
00:29:59.759 --> 00:30:02.359
<v Speaker 3>a second after the Big Bang, long before the first

608
00:30:02.400 --> 00:30:05.720
<v Speaker 3>atoms even combine, let alone, before the first stars are

609
00:30:05.759 --> 00:30:09.640
<v Speaker 3>galaxies formed. Because they predate galaxies, they wouldn't necessarily be

610
00:30:09.720 --> 00:30:13.079
<v Speaker 3>bound inside them. You just drift as the universe expanded.

611
00:30:13.160 --> 00:30:16.200
<v Speaker 3>These primordial black holes would simply be carried along, scattered

612
00:30:16.200 --> 00:30:19.160
<v Speaker 3>throughout the cosmos, drifting in the intergalactic voids.

613
00:30:19.400 --> 00:30:23.519
<v Speaker 2>Okay, if we are seriously entertaining the idea that these

614
00:30:23.559 --> 00:30:27.119
<v Speaker 2>are primordial black holes floating in deep space, we have

615
00:30:27.200 --> 00:30:29.119
<v Speaker 2>to talk about the elephant in the room. We have

616
00:30:29.160 --> 00:30:33.119
<v Speaker 2>to talk about the dark matter connection. Oh yeah, the

617
00:30:33.200 --> 00:30:33.720
<v Speaker 2>big one.

618
00:30:33.799 --> 00:30:36.759
<v Speaker 3>Because this is where this research scales up from Hey

619
00:30:36.799 --> 00:30:40.240
<v Speaker 3>we found a missing black hole. Two, we might be

620
00:30:40.279 --> 00:30:43.680
<v Speaker 3>potentially solving one of the biggest, most enduring mysteries in

621
00:30:43.799 --> 00:30:44.599
<v Speaker 3>all of physics.

622
00:30:44.640 --> 00:30:49.000
<v Speaker 2>It is the ultimate cosmological crossover episode. I mean, for decades,

623
00:30:49.039 --> 00:30:51.839
<v Speaker 2>since the pioneering work of astronomers like VERA. Rubin and

624
00:30:51.880 --> 00:30:55.240
<v Speaker 2>Fritz Wicky, scientists have known that the visible matter in

625
00:30:55.279 --> 00:30:59.119
<v Speaker 2>the universe, the stars, the gas clouds, the planets, us

626
00:30:59.640 --> 00:31:02.440
<v Speaker 2>it only accounts for a tiny fraction of the actual

627
00:31:02.440 --> 00:31:05.720
<v Speaker 2>mass out there, fifteen percent, right roughly. Yeah, when we

628
00:31:05.759 --> 00:31:08.559
<v Speaker 2>look at how galaxies rotate the stars and the outer

629
00:31:08.720 --> 00:31:11.759
<v Speaker 2>edges are moving way too fast. Based on the amount

630
00:31:11.799 --> 00:31:15.039
<v Speaker 2>of visible matter we can see, those galaxies should literally

631
00:31:15.039 --> 00:31:18.160
<v Speaker 2>fling themselves apart. The gravity of the glowing stuff isn't

632
00:31:18.160 --> 00:31:20.000
<v Speaker 2>strong in us to hold them together. But they don't

633
00:31:20.039 --> 00:31:23.160
<v Speaker 2>fly apart. They hold together, which means there has to

634
00:31:23.200 --> 00:31:27.519
<v Speaker 2>be an immense amount of invisible mass providing extra gravity.

635
00:31:28.200 --> 00:31:30.079
<v Speaker 2>We call it dark matter, but let's be honest, that's

636
00:31:30.119 --> 00:31:33.480
<v Speaker 2>just a placeholder name for the invisible stuff creating the

637
00:31:33.480 --> 00:31:35.640
<v Speaker 2>extra gravity that we don't understand precisely.

638
00:31:35.880 --> 00:31:38.400
<v Speaker 3>It's a label for our ignorance. And the particle physics

639
00:31:38.400 --> 00:31:42.920
<v Speaker 3>community has spent decades looking for new exotic subatomic particles

640
00:31:42.920 --> 00:31:47.119
<v Speaker 3>to explain it, things called whimps weakly interacting massive particles,

641
00:31:47.559 --> 00:31:51.359
<v Speaker 3>But despite billions of dollars and incredibly sensitive underground detectors,

642
00:31:51.920 --> 00:31:55.200
<v Speaker 3>we haven't found a single one, which has led many

643
00:31:55.240 --> 00:31:59.640
<v Speaker 3>astrophysicists to revive an older theory. What if dark matter

644
00:31:59.720 --> 00:32:03.359
<v Speaker 3>is an a microscopic new particle. What if it's macroscopic?

645
00:32:03.559 --> 00:32:06.200
<v Speaker 2>What if the universe is simply teeming with an unseen

646
00:32:06.240 --> 00:32:08.119
<v Speaker 2>population of primordial.

647
00:32:07.559 --> 00:32:11.799
<v Speaker 3>Black holes exactly because they would exert massive gravitational influence.

648
00:32:11.839 --> 00:32:14.920
<v Speaker 3>They emit absolutely zero light, and they don't interact with

649
00:32:15.000 --> 00:32:17.200
<v Speaker 3>regular matter unless it falls right into them.

650
00:32:17.319 --> 00:32:20.079
<v Speaker 2>They perfectly fit the job description of dark matter. They do.

651
00:32:20.279 --> 00:32:23.880
<v Speaker 3>So, Juanzu's team took their two candidate black holes, looked

652
00:32:23.880 --> 00:32:27.039
<v Speaker 3>at the volume of space sche Mi surveyed to find them,

653
00:32:27.319 --> 00:32:31.119
<v Speaker 3>and calculated the statistical implications. They ask, if these two

654
00:32:31.200 --> 00:32:35.319
<v Speaker 3>micro lensing events are indeed real primordial black holes, what

655
00:32:35.400 --> 00:32:37.920
<v Speaker 3>does that imply for the dark matter population as a whole?

656
00:32:38.240 --> 00:32:40.880
<v Speaker 2>And the math that came out with this fascinating They

657
00:32:40.960 --> 00:32:43.920
<v Speaker 2>extrapolated from their detections and determined that if these are

658
00:32:43.960 --> 00:32:47.759
<v Speaker 2>true primordial black holes, then black holes specifically in these

659
00:32:47.799 --> 00:32:51.000
<v Speaker 2>intermediate mass ranges the five hundred to six hundred and

660
00:32:51.000 --> 00:32:54.039
<v Speaker 2>fifteen hundred to twenty five hundred solar mass brackets, could

661
00:32:54.079 --> 00:32:56.960
<v Speaker 2>account for approximately four percent of all the dark matter

662
00:32:57.000 --> 00:32:57.599
<v Speaker 2>in the universe.

663
00:32:57.880 --> 00:33:00.200
<v Speaker 3>Now, four percent might sound like a small sligh of

664
00:33:00.200 --> 00:33:02.759
<v Speaker 3>the pie to someone outside the field, but in the

665
00:33:02.799 --> 00:33:05.480
<v Speaker 3>context of dark matter, where we have spent decades with

666
00:33:05.559 --> 00:33:09.680
<v Speaker 3>exactly zero percent of it definitively identified literally zero yes, zero,

667
00:33:10.279 --> 00:33:13.720
<v Speaker 3>So finding an entire specific category of objects that can

668
00:33:13.759 --> 00:33:16.960
<v Speaker 3>count for four percent is a revolutionary leap. It provides

669
00:33:17.000 --> 00:33:19.880
<v Speaker 3>a massive tangible constraint on cosmological models.

670
00:33:20.079 --> 00:33:22.519
<v Speaker 2>If you're wondering why finding four percent if something is

671
00:33:22.519 --> 00:33:25.079
<v Speaker 2>a big deal, think about it this way. You have

672
00:33:25.119 --> 00:33:28.759
<v Speaker 2>a massive jigsaw puzzle with missing pieces. For years, you

673
00:33:28.759 --> 00:33:31.680
<v Speaker 2>didn't even know what color the missing pieces were. Now

674
00:33:31.839 --> 00:33:34.160
<v Speaker 2>someone has just found a handful of pieces and proved

675
00:33:34.160 --> 00:33:37.440
<v Speaker 2>they are blue. It doesn't finish the puzzle, but it

676
00:33:37.480 --> 00:33:39.480
<v Speaker 2>completely changes how you look for the rest of them.

677
00:33:40.039 --> 00:33:43.000
<v Speaker 3>It is a profound constraint. It begins to chip away

678
00:33:43.039 --> 00:33:47.039
<v Speaker 3>at the absolute unknown. But what's equally impressive, and what

679
00:33:47.119 --> 00:33:50.240
<v Speaker 3>makes this a truly rigorous piece of science, is how

680
00:33:50.279 --> 00:33:54.319
<v Speaker 3>they handled the alternative scenario. The statistical analysis in the

681
00:33:54.319 --> 00:33:57.720
<v Speaker 3>paper doesn't just rely on hoping their interpretation is right.

682
00:33:58.240 --> 00:34:01.480
<v Speaker 2>Yes. What fascinating me about this paper is that this

683
00:34:01.559 --> 00:34:04.559
<v Speaker 2>is a win win for science. The scientific method is

684
00:34:04.640 --> 00:34:07.640
<v Speaker 2>working flawlessly here because even if these detections turn out

685
00:34:07.640 --> 00:34:10.119
<v Speaker 2>to be false alarms, even if we later prove that

686
00:34:10.159 --> 00:34:12.920
<v Speaker 2>these specific echoes weren't caused by black holes at all,

687
00:34:13.159 --> 00:34:15.119
<v Speaker 2>the math still works backward to give us an answer.

688
00:34:15.280 --> 00:34:15.880
<v Speaker 3>It really does.

689
00:34:16.039 --> 00:34:19.000
<v Speaker 2>It's like playing a massive cosmic game of guess. Who

690
00:34:19.719 --> 00:34:22.800
<v Speaker 2>Even when you ask does the suspect have glasses and

691
00:34:22.840 --> 00:34:27.079
<v Speaker 2>the universe says no. That no is incredibly valuable because

692
00:34:27.159 --> 00:34:29.639
<v Speaker 2>it helps you eliminate a huge swath of suspects on

693
00:34:29.679 --> 00:34:30.800
<v Speaker 2>the board exactly.

694
00:34:31.199 --> 00:34:34.679
<v Speaker 3>This is the failure scenario, and in Baesian statistics, a

695
00:34:34.760 --> 00:34:38.679
<v Speaker 3>null result is just as mathematically valuable as a positive detection.

696
00:34:38.880 --> 00:34:42.159
<v Speaker 3>A null result right, the authors calculated that if these

697
00:34:42.239 --> 00:34:45.679
<v Speaker 3>candidates are not true gravitational lensing signals, if there are

698
00:34:45.760 --> 00:34:49.320
<v Speaker 3>actually zero intermedia mass black holes acting as lenses in

699
00:34:49.360 --> 00:34:52.719
<v Speaker 3>the entire chatching data set, we still learn something vital

700
00:34:52.719 --> 00:34:54.960
<v Speaker 3>about the composition of the universe because.

701
00:34:54.639 --> 00:34:56.280
<v Speaker 2>We looked so hard and found nothing.

702
00:34:56.559 --> 00:34:59.280
<v Speaker 3>Right by not finding them in a survey this large

703
00:34:59.280 --> 00:35:02.920
<v Speaker 3>and sensitive, scientists can establish with ninety five percent confidence

704
00:35:02.960 --> 00:35:06.400
<v Speaker 3>that primordial black holes heavier than three hundred solar masses

705
00:35:06.679 --> 00:35:09.239
<v Speaker 3>cannot make up more than thirteen percent of dark matter.

706
00:35:09.559 --> 00:35:13.039
<v Speaker 2>So either we have found the missing middleweight black holes

707
00:35:13.280 --> 00:35:18.159
<v Speaker 2>and simultaneously identified four percent of dark matter, or we

708
00:35:18.280 --> 00:35:21.760
<v Speaker 2>have definitively proven that heavy primordial black holes are not

709
00:35:21.960 --> 00:35:25.599
<v Speaker 2>the primary ingredient of dark matter, capping their entire contribution

710
00:35:25.960 --> 00:35:27.440
<v Speaker 2>at a maximum of thirteen percent.

711
00:35:27.639 --> 00:35:30.960
<v Speaker 3>Either way, the boundaries of the unknown shrink, the error

712
00:35:31.000 --> 00:35:34.039
<v Speaker 3>bars get smaller. We are closing in on the truth.

713
00:35:34.320 --> 00:35:38.239
<v Speaker 2>It is a structural wind for astrophysics. The constraints narrow,

714
00:35:38.719 --> 00:35:41.840
<v Speaker 2>the theoretical models get refined, and the parameters for the

715
00:35:41.840 --> 00:35:46.719
<v Speaker 2>next generation of radio telescopes become infinitely more precise. Absolutely, But,

716
00:35:47.199 --> 00:35:49.880
<v Speaker 2>and there is always a butt in astrophysics. Before we

717
00:35:49.920 --> 00:35:52.760
<v Speaker 2>officially declare the mystery of the missing little solve, before

718
00:35:52.760 --> 00:35:55.960
<v Speaker 2>we rewrite the textbooks on dark matter and primordial cosmology,

719
00:35:56.199 --> 00:35:59.159
<v Speaker 2>there is one massive caveat hanging over this entire study.

720
00:35:59.280 --> 00:36:02.800
<v Speaker 2>The caveat, and this caveat is exactly the kind of complex,

721
00:36:02.960 --> 00:36:06.119
<v Speaker 2>nagging variable that forces scientists to be incredibly cautious.

722
00:36:06.400 --> 00:36:08.519
<v Speaker 3>Is the great scientific what if, and it brings us

723
00:36:08.599 --> 00:36:11.760
<v Speaker 3>right back to our lack of fundamental understanding regarding the

724
00:36:11.800 --> 00:36:13.199
<v Speaker 3>fast radio bursts themselves.

725
00:36:13.360 --> 00:36:16.360
<v Speaker 2>We established earlier that we are using a mysterious flashlight

726
00:36:16.599 --> 00:36:19.280
<v Speaker 2>to find a hidden object. We know the light is

727
00:36:19.320 --> 00:36:23.480
<v Speaker 2>hitting our telescopes as a multipeak structure, an echo. We've

728
00:36:23.519 --> 00:36:26.239
<v Speaker 2>shown how beautifully the math aligns if that echo is

729
00:36:26.320 --> 00:36:29.599
<v Speaker 2>caused by an intermediate mass black hole bending the line.

730
00:36:30.559 --> 00:36:34.320
<v Speaker 2>But the alternative explanation for those multiple peaks. Challenge is

731
00:36:34.320 --> 00:36:36.960
<v Speaker 2>the very foundation of the microlensing theory.

732
00:36:37.119 --> 00:36:40.400
<v Speaker 3>Right, we have to confront the intrinsic emission mechanisms of

733
00:36:40.440 --> 00:36:43.480
<v Speaker 3>the fast radio bursts. Because we do not know what

734
00:36:43.559 --> 00:36:47.119
<v Speaker 3>physical astrophysical process creates an FRB, we cannot say with

735
00:36:47.159 --> 00:36:51.559
<v Speaker 3>absolute certainty how that process operates dynamically from millisecond to millisecond.

736
00:36:51.559 --> 00:36:53.320
<v Speaker 2>Wait, let me make sure I'm following. You're telling me

737
00:36:53.360 --> 00:36:56.519
<v Speaker 2>the multipeak structure, the echo that perfectly aligns with the

738
00:36:56.599 --> 00:37:00.320
<v Speaker 2>general relativity math of a two thousand solar mass black

739
00:37:00.320 --> 00:37:03.559
<v Speaker 2>hole might just be the flashlight flickering twice on its own,

740
00:37:03.960 --> 00:37:06.760
<v Speaker 2>rather than a single continuous light being bent into two

741
00:37:06.840 --> 00:37:07.440
<v Speaker 2>by gravity.

742
00:37:07.519 --> 00:37:10.679
<v Speaker 3>That is exactly the degenerate caveat. It is entirely physically

743
00:37:10.679 --> 00:37:12.679
<v Speaker 3>plausible that the source of the effort be itself.

744
00:37:12.719 --> 00:37:14.719
<v Speaker 2>Stutters. It's stutter. Yeah.

745
00:37:15.000 --> 00:37:17.599
<v Speaker 3>Let's say the burst is caused by a magnetar, a

746
00:37:17.719 --> 00:37:23.159
<v Speaker 3>highly magnetized, rapidly rotating neutron star undergoing a massive starquake

747
00:37:23.239 --> 00:37:25.280
<v Speaker 3>that snaps its magnetic field lines.

748
00:37:25.519 --> 00:37:28.199
<v Speaker 2>A starquake that sounds intense.

749
00:37:28.440 --> 00:37:32.280
<v Speaker 3>It is incredibly intense. If that cataclysmic event pulses rapidly

750
00:37:32.719 --> 00:37:36.719
<v Speaker 3>emitting two distinct bursts separated by a fraction of a millisecond.

751
00:37:37.440 --> 00:37:40.280
<v Speaker 3>Those two pulses would travel across the universe and arrive

752
00:37:40.320 --> 00:37:44.519
<v Speaker 3>at our telescopes looking completely identically indistinguishable from a single

753
00:37:44.960 --> 00:37:47.840
<v Speaker 3>burst that was split into an ego by gravitational lensing.

754
00:37:47.920 --> 00:37:48.920
<v Speaker 2>Oh, that is brutal.

755
00:37:49.000 --> 00:37:52.119
<v Speaker 3>It would perfectly mimic the geometric signature of a black hole.

756
00:37:52.199 --> 00:37:55.880
<v Speaker 2>It's a cosmic counterfeit. The intrinsic stutter of the source

757
00:37:56.079 --> 00:37:59.360
<v Speaker 2>perfectly imitates the gravitational lens. So how do we break

758
00:37:59.440 --> 00:38:02.159
<v Speaker 2>that tie? If the time delay looks exactly the same

759
00:38:02.159 --> 00:38:04.000
<v Speaker 2>on the graph, how do we prove we are seeing

760
00:38:04.000 --> 00:38:07.079
<v Speaker 2>a true spatial echo caused by gravity and not just

761
00:38:07.119 --> 00:38:10.119
<v Speaker 2>an intrinsic flicker from an unstable magnetar.

762
00:38:09.880 --> 00:38:12.199
<v Speaker 3>That is the frontier we are on right now, and

763
00:38:12.280 --> 00:38:14.760
<v Speaker 3>it requires us to look at properties of the light

764
00:38:15.119 --> 00:38:19.679
<v Speaker 3>beyond just when it arrives. It requires an extraordinary level

765
00:38:19.719 --> 00:38:24.360
<v Speaker 3>of rigorous skepticism, which the authors of the paper explicitly acknowledge.

766
00:38:24.400 --> 00:38:28.599
<v Speaker 3>To definitively prove these signatures are intermediate mass black holes,

767
00:38:28.920 --> 00:38:32.000
<v Speaker 3>we need to analyze the polarization of the radio waves.

768
00:38:32.320 --> 00:38:35.360
<v Speaker 2>Polarization Okay, break down how that helps us tell a

769
00:38:35.440 --> 00:38:36.519
<v Speaker 2>stutter from a lens.

770
00:38:37.039 --> 00:38:40.199
<v Speaker 3>Think of polarization as the orientation of the light wave

771
00:38:40.280 --> 00:38:42.519
<v Speaker 3>as it travels. Does it wiggle up and down or

772
00:38:42.599 --> 00:38:43.239
<v Speaker 3>left and right?

773
00:38:43.360 --> 00:38:45.639
<v Speaker 2>Okay? I can picture that like shaking a rope.

774
00:38:45.920 --> 00:38:49.079
<v Speaker 3>Exactly like shaking a rope. When a magnetic field generates

775
00:38:49.079 --> 00:38:52.199
<v Speaker 3>a radio burst, it gives that burst a very specific

776
00:38:52.280 --> 00:38:56.920
<v Speaker 3>polarization angle. If a magnetar stutters and emits two bursts,

777
00:38:57.199 --> 00:38:59.920
<v Speaker 3>the massive magnetic field of the star is likely shift

778
00:39:00.599 --> 00:39:03.440
<v Speaker 3>rotating or violently reorganizing between those two.

779
00:39:03.360 --> 00:39:05.239
<v Speaker 2>Pulses because it's having a starquake right.

780
00:39:05.760 --> 00:39:08.760
<v Speaker 3>Therefore, the second pulse will likely have a slightly different

781
00:39:08.800 --> 00:39:12.400
<v Speaker 3>polarization angle than the first pulse. The microscopic physics of

782
00:39:12.440 --> 00:39:13.880
<v Speaker 3>the source change over time.

783
00:39:14.199 --> 00:39:16.400
<v Speaker 2>I see where you're going with this, But what if

784
00:39:16.440 --> 00:39:17.679
<v Speaker 2>it's a gravitational lens.

785
00:39:18.000 --> 00:39:20.960
<v Speaker 3>If it's a gravitational lens, there is only one single

786
00:39:21.119 --> 00:39:25.320
<v Speaker 3>burst of light. The source is identical. The gravity of

787
00:39:25.360 --> 00:39:29.280
<v Speaker 3>the black hole splits that single burst into two paths.

788
00:39:29.400 --> 00:39:33.079
<v Speaker 3>But gravity is achromatic aromatic. It affects all frequencies and

789
00:39:33.119 --> 00:39:37.280
<v Speaker 3>polarizations exactly equally. It doesn't twist the orientation of the

790
00:39:37.360 --> 00:39:39.920
<v Speaker 3>light differently on the left path versus the right path.

791
00:39:40.400 --> 00:39:42.039
<v Speaker 3>So if we look at the two peaks of the

792
00:39:42.039 --> 00:39:45.119
<v Speaker 3>echo and their polarization angles are identical down to the

793
00:39:45.119 --> 00:39:49.599
<v Speaker 3>finest measurable degree, that strongly implies a single source was lensed. Wow,

794
00:39:49.880 --> 00:39:53.400
<v Speaker 3>if the polarizations are different, it's almost certainly an intrinsic

795
00:39:53.440 --> 00:39:54.480
<v Speaker 3>stutter from the source.

796
00:39:54.719 --> 00:39:57.960
<v Speaker 2>That is an incredibly elegant solution. So why didn't they

797
00:39:58.000 --> 00:40:01.280
<v Speaker 2>just check the polarization in this Chihaim data.

798
00:40:01.000 --> 00:40:05.199
<v Speaker 3>Because capturing that level of granular polarization data for transient

799
00:40:05.239 --> 00:40:07.760
<v Speaker 3>microsecond events is incredibly technically demanding.

800
00:40:07.800 --> 00:40:08.800
<v Speaker 2>It's just too fast.

801
00:40:09.199 --> 00:40:13.360
<v Speaker 3>Yeah, the Chino data provides the time delay beautifully, but

802
00:40:13.559 --> 00:40:18.199
<v Speaker 3>we need more comprehensive, multi layered observational data from next

803
00:40:18.239 --> 00:40:23.119
<v Speaker 3>generation arrays to routinely capture the exact frequency distribution and

804
00:40:23.280 --> 00:40:27.800
<v Speaker 3>subtle polarization wave interference patterns across the peaks to distinguish

805
00:40:27.840 --> 00:40:31.840
<v Speaker 3>a true gravitational echo from a source that just happens

806
00:40:31.840 --> 00:40:33.000
<v Speaker 3>to be flashing twice.

807
00:40:33.400 --> 00:40:35.679
<v Speaker 2>It's like we've been handed an ancient treasure map to

808
00:40:35.679 --> 00:40:38.280
<v Speaker 2>the hidden monsters of the universe. We could see the

809
00:40:38.480 --> 00:40:41.559
<v Speaker 2>X marking the spot the coordinates lineup perfectly, but we're

810
00:40:41.599 --> 00:40:44.119
<v Speaker 2>still trying to learn the specific dialect of the legend

811
00:40:44.119 --> 00:40:46.239
<v Speaker 2>in the corner. We aren't quite sure if we're reading

812
00:40:46.280 --> 00:40:47.280
<v Speaker 2>the topography correctly.

813
00:40:47.360 --> 00:40:50.480
<v Speaker 3>Yet that's a perfect summary of where the science currently stands.

814
00:40:50.639 --> 00:40:53.480
<v Speaker 3>The time catalog has provided us with our most incredible,

815
00:40:53.559 --> 00:40:57.719
<v Speaker 3>mathematically robust candidates to date. The math of strong field

816
00:40:57.760 --> 00:41:01.239
<v Speaker 3>gravity holds up flawlessly. If these are in lenses, the

817
00:41:01.280 --> 00:41:05.639
<v Speaker 3>puzzle pieces fit they do. The profound implications for primordial

818
00:41:05.639 --> 00:41:08.840
<v Speaker 3>black holes floating in voids and their contribution to dark

819
00:41:08.880 --> 00:41:13.639
<v Speaker 3>matter are revolutionary. But the final definitive proof, the thing

820
00:41:13.679 --> 00:41:16.400
<v Speaker 3>that will lock this into the textbooks, requires us to

821
00:41:16.480 --> 00:41:19.559
<v Speaker 3>crack the code of the fast radio bursts themselves.

822
00:41:20.079 --> 00:41:22.679
<v Speaker 2>It is an incredible journey just to recap how far

823
00:41:22.719 --> 00:41:25.440
<v Speaker 2>we've come. We started with a massive missing generation and

824
00:41:25.480 --> 00:41:29.239
<v Speaker 2>the cosmic family tree. The intermediate mass black holes that

825
00:41:29.280 --> 00:41:32.880
<v Speaker 2>the laws of physics demand must exist, but observation has

826
00:41:33.000 --> 00:41:35.599
<v Speaker 2>entirely failed to confirm. To find them, we had to

827
00:41:35.599 --> 00:41:38.800
<v Speaker 2>stop staring into the noisy, chaotic centers of dense star

828
00:41:38.880 --> 00:41:44.119
<v Speaker 2>clusters and instead repurposed mysterious microsecond flashes of extreme radio

829
00:41:44.199 --> 00:41:48.280
<v Speaker 2>waves from deep space as our cosmic flashlights exactly by

830
00:41:48.320 --> 00:41:51.440
<v Speaker 2>analyzing how the extreme gravity of hidden mass bends that

831
00:41:51.559 --> 00:41:54.920
<v Speaker 2>light to create split second echoes, scientists have essentially found

832
00:41:54.920 --> 00:41:58.199
<v Speaker 2>a way to mathematically weigh completely invisible objects billions of

833
00:41:58.280 --> 00:42:02.039
<v Speaker 2>light years away, so they are simultaneously closing in on

834
00:42:02.079 --> 00:42:04.519
<v Speaker 2>the secrets of dark matter and the chaotic quite a

835
00:42:04.599 --> 00:42:07.119
<v Speaker 2>moment's just fractions of a second after the Big Bang.

836
00:42:07.360 --> 00:42:12.400
<v Speaker 3>It truly showcases the incredible ingenuity and resilience of modern astrophysics.

837
00:42:13.000 --> 00:42:16.480
<v Speaker 3>When that direct, obvious approach fails, you don't give up.

838
00:42:16.960 --> 00:42:19.920
<v Speaker 3>You use the warping fabric of space time itself as

839
00:42:19.960 --> 00:42:20.639
<v Speaker 3>your instrument.

840
00:42:20.760 --> 00:42:22.760
<v Speaker 2>It really does. And I want to leave you with

841
00:42:22.840 --> 00:42:26.239
<v Speaker 2>one final lingering thought to ponder tonight. As you look

842
00:42:26.320 --> 00:42:29.480
<v Speaker 2>up at the night sky. We are so entirely used

843
00:42:29.480 --> 00:42:33.800
<v Speaker 2>to looking at the stars, the bright, spiraling galaxies, the visible,

844
00:42:33.880 --> 00:42:37.280
<v Speaker 2>glowing structure of the universe. We assume that the light

845
00:42:37.360 --> 00:42:38.280
<v Speaker 2>is where the action is.

846
00:42:38.400 --> 00:42:39.360
<v Speaker 3>It's natural to think that.

847
00:42:39.679 --> 00:42:42.960
<v Speaker 2>But if this research holds true, if these middleweight black

848
00:42:43.000 --> 00:42:47.159
<v Speaker 2>holes are indeed primordial, isolated and making up significant chunks

849
00:42:47.199 --> 00:42:49.840
<v Speaker 2>of the dark matter that silently binds the cosmos together,

850
00:42:50.280 --> 00:42:53.880
<v Speaker 2>then the vast seemingly empty black voids of deep space

851
00:42:53.920 --> 00:42:57.239
<v Speaker 2>between those glowing galaxies aren't empty at all, far from it,

852
00:42:57.280 --> 00:43:01.480
<v Speaker 2>they are silently teeming with invisible ancient behemos. Middleweight Monster

853
00:43:01.559 --> 00:43:04.440
<v Speaker 2>is born at the very dawn of time, completely undetectable

854
00:43:04.440 --> 00:43:08.119
<v Speaker 2>to us, drifting alone in the absolute dark until they briefly,

855
00:43:08.159 --> 00:43:10.679
<v Speaker 2>fleetingly cast their shadow in the light of a microsecond

856
00:43:10.760 --> 00:43:12.960
<v Speaker 2>radio flash. We still don't even fully understand