Speaker 1: Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
Speaker 1: with our soothing Bedtime Astronomie podcast. Each episode offers a
Speaker 1: gentle journey through the stars, planets, and beyond, perfect for
Speaker 1: unwinding after a long day. Let's travel through the mysteries
Speaker 1: of the universe as you drift off into a peaceful
Speaker 1: slumber under the night sky.
Speaker 2: So I want you to imagine stepping outside tomorrow morning.
Speaker 2: You know you've got your coffee in hand.
Speaker 3: That's time of the day.
Speaker 2: Oh absolutely, So you walk out onto your porch, you
Speaker 2: look up at the morning sky, and instead of our
Speaker 2: single familiar yellow sugn just kind of rising in the east, right,
Speaker 2: you see five massive burning spheres of plasma just right
Speaker 2: there in the sky.
Speaker 3: That would definitely wake you up faster than the coffee.
Speaker 2: Right. I mean, they'd be casting these multiple overlapping shadows
Speaker 2: on your lawn. You'd have different hues of orange and
Speaker 2: red and this stark, blinding white.
Speaker 3: It sounds like a backdrop for a massive space opera.
Speaker 2: Or something exactly like something cooked up into sci fi
Speaker 2: writer's room. But the crazy thing is in our immediate
Speaker 2: cosmic neighborhood. This is actually an absolute, ongoing reality.
Speaker 3: Yeah, it really is. And I think you know our
Speaker 3: daily experience waking up to just one sun that makes
Speaker 3: its journey across the sky completely alone. It creates this massive,
Speaker 3: ingrained psychological bias for us. We just naturally assume the
Speaker 3: rest of the universe operates on this exact same single
Speaker 3: sun blueprint, because.
Speaker 2: That's all we know. But being a single star like
Speaker 2: our sun actually makes us the absolute weirdos of the galaxy,
Speaker 2: doesn't it.
Speaker 3: We really are the odd ones out. I mean that
Speaker 3: human experience is just incredibly localized. We project our solar
Speaker 3: system's orderly, single anchor structure onto the rest of the.
Speaker 2: Cosmos, which makes sense logically, sure it does.
Speaker 3: But the sheer volume of stars out there that are
Speaker 3: actively bound up in these complex gravitational relationships with other stars,
Speaker 3: it's staggering.
Speaker 2: It's a crowded universe out there.
Speaker 3: Oh, Incredibly, the universe is a far more dynamic and
Speaker 3: chaotic and just crowded environment than a casual glance at
Speaker 3: our night sky would ever lead you to believe.
Speaker 2: So today our mission is to basically dismantle that bias completely.
Speaker 2: We're going to map out the precise relationship statuses of
Speaker 2: the star's closest.
Speaker 3: To us, which is such a fascinating project, it really is.
Speaker 2: Astronomers the University Madrid have just completed this incredible, definitive
Speaker 2: census of our local cosmic neighborhood and they're combining you know,
Speaker 2: modern space telescope data with century old catalogs.
Speaker 3: And we are going to explore exactly who is paired up,
Speaker 3: who is flying solo and why. Untangling these incredibly complex
Speaker 3: stellar relationships is so important.
Speaker 2: Right because it's essentially the ultimate prerequisite for one of
Speaker 2: the greatest quests in human history, which is finding a.
Speaker 3: Second Earth exactly. I mean, if the ultimate goal is
Speaker 3: to find habitable planets, you know, worlds where liquid water
Speaker 3: could exist and life might thrive, we first have to
Speaker 3: thoroughly understand the stars those planets might be orbiting.
Speaker 2: You can't just blindly point a telescope and hope for
Speaker 2: the best.
Speaker 3: No, you really can't. The only way to build that
Speaker 3: understanding is to know exactly what is happening in our
Speaker 3: own backyard. We cannot filter the noise of the deep
Speaker 3: universe if we do not even know who is living
Speaker 3: next door.
Speaker 2: Okay, so let's start by defining that backyard. Yeah, because
Speaker 2: we need a boundary, right, We can't just say nearby.
Speaker 3: In astronomy, nearby could mean a million light years.
Speaker 2: Yeah, exactly. So the astronomers compiling this definitive map, they
Speaker 2: do this highly specific mathematical bubble around our solar system.
Speaker 2: The boundary is set at exactly ten parsecs away.
Speaker 3: From the Sun, extending in every single direction to form
Speaker 3: a perfect sphere.
Speaker 2: Right, and for anyone doing the cosmic math at home,
Speaker 2: ten parsecs translates to thirty two point six light years.
Speaker 3: Which is a very specific number.
Speaker 2: It is, and inside this specific ten carsec bubble there
Speaker 2: are exactly four hundred twenty four known stellar and substellar objects.
Speaker 2: But I mean thirty two point six light years feels
Speaker 2: strangely arbitrary.
Speaker 3: It does sound random at first.
Speaker 2: Yeah, because the Milky Way Galaxy is over one hundred
Speaker 2: thousand light years across. So why draw the lines so
Speaker 2: close to home? Why ten parsecs?
Speaker 3: Well, it all comes down to this foundational concept in
Speaker 3: observational astronomy, which is completeness.
Speaker 2: Completeness meaning we know everything that's.
Speaker 3: In there exactly. The primary enemy of any astronomical survey
Speaker 3: is distance. The further out into the galaxy you look,
Speaker 3: the harder it becomes to visually resolve the fine details
Speaker 3: of a star system.
Speaker 2: Like trying to see the details of a car from
Speaker 2: ten miles away.
Speaker 3: Precisely, it becomes intensely mathematically difficult to see whether a
Speaker 3: star has a companion hidden right next to it, because
Speaker 3: it just gets lost in the blinding glare of the
Speaker 3: primary star.
Speaker 2: You know, I was thinking about this like a neighborhood
Speaker 2: watch program.
Speaker 3: Oh I like that?
Speaker 2: How so well, it's incredibly easy to know exactly who
Speaker 2: lives on your own street. Right, you see your neighbors
Speaker 2: taking out the trash, You recognize their You know exactly
Speaker 2: who lives in which house. Sure, you might even have
Speaker 2: a pretty good read on the street behind yours, But
Speaker 2: if you try to figure out who is permanently crashing
Speaker 2: on the couch of a house like three towns away.
Speaker 3: You wouldn't have a clue exactly.
Speaker 2: From where you're standing. It is completely impossible. You just
Speaker 2: cannot see through the structural noise of the intervening houses
Speaker 2: and the distance to know for sure.
Speaker 3: That captures the structural problem perfectly, expanding the bubble to
Speaker 3: say fifty or one hundred parsecs would introduce a massive
Speaker 3: amount of uncertainty into the data.
Speaker 2: We just start missing the cosmic couch surfers.
Speaker 3: Exactly, We would start missing things. By strictly limiting the
Speaker 3: boundary to exactly ten parsecs, astronomers can mathematically lower the
Speaker 3: probability of missing those starry companions that are hiding in
Speaker 3: the wings.
Speaker 2: So it's about confidence in the data, oh, one hundred percent.
Speaker 3: This constraint allows for a very high degree of statistical
Speaker 3: confidence the map is considered complete. We know we haven't
Speaker 3: missed any hidden roommate.
Speaker 2: Okay, but wait, that still doesn't quite add up for me.
Speaker 3: Oh why not?
Speaker 2: Because we currently have telescopes operating in space that are
Speaker 2: sending back crystal clear, high definition images of galaxies that
Speaker 2: are billions of late years away.
Speaker 3: Oh right, like James Webb and Hubble.
Speaker 2: Yeah, we are literally looking back in time to the
Speaker 2: dawn of the universe. So if the optics exist to
Speaker 2: capture a galaxy on the edge of the observable universe,
Speaker 2: why is it mechanically so difficult to spot a single
Speaker 2: companion star that is just say, fifteen parsex down the
Speaker 2: cosmic street. That's a really great point right, Why does
Speaker 2: the physics fall apart at such a relatively short distance.
Speaker 3: Well, the distinction lies in what those telescopes are actually resolving.
Speaker 3: When you look at a galaxy billions of late years away,
Speaker 3: you are not resolving individual stars.
Speaker 2: You're just seeing the whole thing at once.
Speaker 3: Exactly, you are observing the combined massive glow of hundreds
Speaker 3: of billions of stars spread out over an unfathomably huge area.
Speaker 3: It's a massive smear of light.
Speaker 2: Ok.
Speaker 3: When you look at a star system just fifteen parsecs away,
Speaker 3: you are trying to resolve a tiny, specific point source
Speaker 3: of light.
Speaker 2: You are looking for a single microscopic.
Speaker 3: Dot, and that dot is unimaginably bright. I mean, stars
Speaker 3: are colossal nuclear fusion engines. They create a blinding amount
Speaker 3: of glare.
Speaker 2: Right, They are just reflecting light, They're making.
Speaker 3: It exactly so. If a companion star is orbiting relatively
Speaker 3: close to a primary star, the light from the primary
Speaker 3: completely washes out the dimmer companion.
Speaker 2: Ah. I see.
Speaker 3: Think of it like trying to spot a firefly hovering
Speaker 3: three inches away from a stadium floodlight while you are
Speaker 3: standing two miles down the road.
Speaker 2: Oh wow, Yeah, the sheer volume of photons from the
Speaker 2: floodlight would just utterly destroy your ability to perceive the
Speaker 2: firefly exactly.
Speaker 3: The firefly is completely swallowed by the visual noise.
Speaker 2: So it's not a distance problem, it's a glare problem.
Speaker 3: Precisely. This limitation is governed by something called angular resolution.
Speaker 3: No matter how perfectly polished your telescope mirror is or
Speaker 3: how advanced your sensors are, light ultimately behaves as a wave.
Speaker 2: Right, So when light.
Speaker 3: Waves past the edges of a telescope's aperture, they bend
Speaker 3: and spread out. This is a phenomenon called diffraction diffraction, okay,
Speaker 3: And this creates a tiny blur around every point of
Speaker 3: light on the sensor. If two stars are too close
Speaker 3: together in the sky, their diffraction blurs.
Speaker 2: Overlap and they just merge into a single blob of
Speaker 2: light exactly.
Speaker 3: Keeping the sensus tightly constrained to ten parsecs means the
Speaker 3: physical distance between the stars translates to a wide enough
Speaker 3: angle in our sky. It ensures the floodlight and the
Speaker 3: firefly appear far enough apart that our instruments can reliably
Speaker 3: separate them.
Speaker 2: Okay, that makes that urbitrainer would make total sense. It's
Speaker 2: literally the physical limit of knowing our data is pure
Speaker 2: exactly now, compiling a flawless map of four hundred and
Speaker 2: twenty four objects isn't something you do by just pointing
Speaker 2: a backyard telescope at the sky and taking notes, right,
Speaker 2: Definitely not the data required to prove these objects exist,
Speaker 2: and more importantly, to prove they are at interacting with
Speaker 2: each other. That must be monumental.
Speaker 3: Oh, it's staggering. The Census is the culmination of combining
Speaker 3: two of the most sophisticated massive data sets ever compiled
Speaker 3: by humanity.
Speaker 2: Wow, what are they?
Speaker 3: The structural backbone of this map comes from the d
Speaker 3: R three data release from the European Space Agency's Gaya telescope.
Speaker 2: Gaya, I've heard of that one.
Speaker 3: It's an incredible piece of technology. Gaya is a space
Speaker 3: observatory specifically designed for astrometry.
Speaker 2: That's the precise measurement of where things.
Speaker 3: Are, vacation distance, and motion exactly. Gaya is essentially building
Speaker 3: a highly dynamic, three dimensional map of the entire Milky
Speaker 3: Way Galaxy.
Speaker 2: That's ambitious, very.
Speaker 3: It measures the positions of over a billion stars with
Speaker 3: a level of precision that is honestly difficult to overstate.
Speaker 3: It can measure the width of a human hair from
Speaker 3: hundreds of miles away.
Speaker 2: Seriously, that is insane.
Speaker 3: It's phenomenal engineering. But positional data is really only half
Speaker 3: the puzzle.
Speaker 2: Right, because just knowing where two stars are it doesn't
Speaker 2: mean they are interacting exactly.
Speaker 3: To know if stars are actually in a relationship, you
Speaker 3: need movement over time. That is where the researcher is
Speaker 3: brought in the Washington Double Star Catalog.
Speaker 2: Now, I was looking at the history of the Washington
Speaker 2: Double Star Catalog. It is fascinating because it isn't just
Speaker 2: a modern digital list. It represents decades, even centuries of
Speaker 2: human observation.
Speaker 3: It really is a historical treasure. It's the world's principal
Speaker 3: database of visual double stars. It actually contains historical observations
Speaker 3: dating all the way back to the nineteenth century.
Speaker 2: Wow, so people with early telescopes sketching things out basically.
Speaker 3: Yeah, And that historical data is combined with decades of
Speaker 3: modern radial velocity measurements.
Speaker 2: Radio velocity being how fast a star is moving along
Speaker 2: our line of sight, like either toward us or away
Speaker 2: from us.
Speaker 3: You've got it perfectly by fusing Guya's ultra precise three
Speaker 3: D positioning. With the deep historical motion data from the
Speaker 3: Washington Catalog, astronomers could trace the exact trey objectories of
Speaker 3: these objects over time, so.
Speaker 2: They can see the actual dance.
Speaker 3: Yes, they could definitively prove which stars were locked in
Speaker 3: a gravitational embrace and which were just optical illusions.
Speaker 2: Optical illusions like stars that look close together from Earth
Speaker 2: but are actually separated by vast distances in deep space.
Speaker 3: Exactly we call those optical binaries. They just happen to
Speaker 3: line up perfectly from our vantage point, but they have
Speaker 3: nothing to do with each other.
Speaker 2: Okay, so the ten Parsak bubble is set, the pristine
Speaker 2: data is gathered, and all the false positives those optical
Speaker 2: illusions are filtered out. Let's dig into the actual census results.
Speaker 2: Let's do it. Who is actually paired up in our neighborhood.
Speaker 2: Out of the four hundred and twenty four objects inside
Speaker 2: this bubble, two hundred and fifteen of them are bound
Speaker 2: up in multiple star systems, which means over half the
Speaker 2: population is coupled up. Literally, more than half the neighborhood
Speaker 2: is in a relationship, and they aren't just in simple pairs. Either.
Speaker 3: No, it gets much more complicated.
Speaker 2: These two hundred and fifteen objects are distributed across ninety
Speaker 2: two distinct multiple star systems, and the structural breakdown of
Speaker 2: these systems is shockingly diverse.
Speaker 3: It really runs the gamut.
Speaker 2: Right, So there are sixty eight classic double star systems,
Speaker 2: you know, binaries. But then there are nineteen triple star systems.
Speaker 3: Three stars all dancing together.
Speaker 2: Yeah. And then there are three quadruple systems, and perhaps
Speaker 2: the most mind bending of all, there are two incredibly
Speaker 2: rare kintuple star systems. Five star, five separate stars, all
Speaker 2: gravitationally bound to each other, existing is a single cohesive unit.
Speaker 3: You know. Visualizing a system with five massive bodies of
Speaker 3: burning plasma is challenging because our brains just naturally default
Speaker 3: to our own solar system model.
Speaker 2: Right. I was reading about the structural dynamics of these
Speaker 2: quintuple systems and my mind went straight to how they
Speaker 2: even organize themselves without crashing.
Speaker 3: It's a delicate balance.
Speaker 2: Because you can't just have five stars orbiting a single
Speaker 2: point like a cosmic merry ground.
Speaker 3: Right.
Speaker 2: The n body problem in physics dictates that throwing five
Speaker 2: massive objects into a random clump just results in pure.
Speaker 3: Chaos, absolute chaos. They would violently fling each other.
Speaker 2: Yeah, they completely destabilize the orbits until the system either
Speaker 2: collapsed inward on itself or forcefully ejected stars out into
Speaker 2: deep space.
Speaker 3: Exactly. So, to survive for billions of years, gravity forces
Speaker 3: them into highly organized, compartmentalized layers.
Speaker 2: What's the term for that.
Speaker 3: It's called a hierarchical structure. They do not orbit a
Speaker 3: central star. They orbit a shared center of mass, a
Speaker 3: shared center, yes, and there's a barry center. And they
Speaker 3: do this through nested levels of organization.
Speaker 2: Nested levels. You know. It reminds me of the intricate
Speaker 2: gears inside of mechanical Swiss watch.
Speaker 3: Oh that's a brilliant comparison.
Speaker 2: Because you don't have five gears all grinding against the
Speaker 2: exact same central axle. You have a massive, slow moving
Speaker 2: outer gear, and then nested inside that you have small
Speaker 2: assemblies spinning independently, and within those even tighter, faster moving parts.
Speaker 3: The watch analogy perfectly captures the mechanics. So in a
Speaker 3: quintuple system, you might have two stars in a very
Speaker 3: tight binary orbits circling each other.
Speaker 2: Rapidly, like the ticking secondhand.
Speaker 3: Exactly, then a massive distance away, but still within the
Speaker 3: exact same system. You have another tight binary pair.
Speaker 2: Okay, two separate pairs, Yes, And those.
Speaker 3: Two separate binary pairs will then orbit each other.
Speaker 2: Wait, the pairs orbit each other.
Speaker 3: Yes, The gravitational center of pair A orbits the gravitational
Speaker 3: center of pair B. They treat the other pair almost
Speaker 3: as if it were a single extra heavy star.
Speaker 2: Orbiting pairs of orbiting pairs. That is dizzying. And the
Speaker 2: fifth star.
Speaker 3: The fifth star is often situated in an incredibly wide orbit,
Speaker 3: just slowly circling the entire inner quadruple structure from a
Speaker 3: massive distance.
Speaker 2: Like the outer casing of the watch.
Speaker 3: Exactly, moving at a glacial pace compared to the rapid
Speaker 3: ticking of the inner binaries. And the sheer vastness of
Speaker 3: space between these hierarchical levels is actually what preserves.
Speaker 2: The system, because they're kept far enough apart to not interfere.
Speaker 3: Right, the gravitational forces at play locally within a tight
Speaker 3: binary are intense, but because the what X structural level
Speaker 3: is located so far away that competing gravitational poll is diluted.
Speaker 2: Ah I see, they establish a long term stable resonance Chris.
Speaker 2: But Okay, if I am a planet in one of
Speaker 2: these quadruple or quintuple systems, what does my existence even
Speaker 2: look like with all these competing gravitational wells. Do planets
Speaker 2: even survive in these environments? Or are they just shredded
Speaker 2: into asteroid belts.
Speaker 3: It's a rough neighborhood for a planet. The gravitational environment
Speaker 3: is incredibly hostile unless they settle into very specific mathematically
Speaker 3: safe zones. Safe zones like where well a planet can
Speaker 3: survive if it is in an extremely tight close orbit
Speaker 3: around just one of the individual stars. In that scenario,
Speaker 3: it effectively ignores the distant pole of the other stars
Speaker 3: in the system.
Speaker 2: It just hugs its parent star really tightly exactly.
Speaker 3: Or on the flip side, a planet can exist in
Speaker 3: a circumbinary orbit.
Speaker 2: Circumbinary meaning orbiting the whole.
Speaker 3: Thing right, orbiting incredibly far away from the entire complex,
Speaker 3: treating the inner mess of stars as a single gravitational point.
Speaker 2: Okay, so way inside or way outside.
Speaker 3: Exactly anything in the middle ground, the spaces between the
Speaker 3: interacting stars. That is a dynamically unstable death.
Speaker 2: Zone, a death zone.
Speaker 3: A planet caught there would eventually be ejected from the
Speaker 3: system entirely or pulled into a catastrophic collision course with
Speaker 3: a star.
Speaker 2: So no middle ground. The mechanics are just awe inspiring.
Speaker 2: But you know, beyond just mapping the structures, the Census
Speaker 2: revealed this really striking mathematical rule about who actually ends
Speaker 2: up in these complex relationships.
Speaker 3: Oh, yes, the relationship between mass and multiplicity.
Speaker 2: Right, there is a definitive, unyielding link between a star's
Speaker 2: mass and its relationship status.
Speaker 3: It's fascinating.
Speaker 2: If a star is categorized as a heavyweight, meaning it
Speaker 2: possesses more than half the mass of our Sun, it
Speaker 2: has a massive forty one percent chance of being paired
Speaker 2: up with at least one companion.
Speaker 3: Almost a coin flip. Mass dictates cosmic sociability. The heavier
Speaker 3: the star, the more likely it is to exist in
Speaker 3: a complex system.
Speaker 2: But then the complete opposite is true for the lightweights.
Speaker 2: We're talking about objects under point one solar masses.
Speaker 3: Right, the red dwarfs and the brown dwarfs.
Speaker 2: Yeah, for these lightweights, the fraction of being found in
Speaker 2: a multi star system absolutely plummets. It drops all the
Speaker 2: way down to just nine percent. They actively seem to
Speaker 2: avoid entanglements, and that.
Speaker 3: Massive statistical drop off from forty one percent down to
Speaker 3: nine percent is not just a quirk of our local neighborhood. No, No,
Speaker 3: it provides crucial forensic evidence for one of the most
Speaker 3: intense ongoing debates in stellar astrophysics, the mystery of how
Speaker 3: substellar objects actually form.
Speaker 2: The first place interesting because I look at gravity like
Speaker 2: a form of cosmic social currency.
Speaker 3: Social currency.
Speaker 2: Yeah, Like, the heavier you are, the more gravitational charisma
Speaker 2: you possess, you can attract other bodies, lock them into orbit,
Speaker 2: and basically hold on to them through the chaotic early
Speaker 2: days of star formation.
Speaker 3: That's a great way to visualize it. The heavyweights clearly
Speaker 3: have that currency.
Speaker 2: They travel in packs, right, But it begs the question
Speaker 2: regarding these tiny red and brown dwarfs. Are they born
Speaker 2: alone because they simply lack the gravitational mass to attract
Speaker 2: a partner, or is something more violent happening?
Speaker 3: More violent?
Speaker 2: Could they have been born into a larger group dynamic
Speaker 2: and then violently kicked out.
Speaker 3: Well, you are outlining the two leading models for brown
Speaker 3: dwarf formation right there. Oh yep. But to understand the debate,
Speaker 3: you first have to look at what a brown dwarf
Speaker 3: actually is. It is the ultimate cosmic tweener, a.
Speaker 2: Tweener, not a planet, not a star exactly.
Speaker 3: It is significantly more massive than a gas giant planet
Speaker 3: like Jupiter, but it does not have quite enough mass
Speaker 3: to generate the core pressure needed to ignite sustained nuclear fusion.
Speaker 2: Of hydrogen, so it never caught fire.
Speaker 3: Right. It glows faintly from the residual heat of its formation,
Speaker 3: but it is not a true hydrogen burning stars kind
Speaker 3: of smoldering exactly. Now, consider the birthplace of stars. They
Speaker 3: form in these massive freezing cloud clouds of interstellar gas
Speaker 3: and dust called molecular.
Speaker 2: Clouds, okay, giant freezing clouds, right.
Speaker 3: And as these clouds collapse under their own gravity, they
Speaker 3: do not form a single smooth sphere. They fragment into dozens, hundreds,
Speaker 3: or even thousands of dense clumps.
Speaker 2: So it's a messy, very messy.
Speaker 3: This fragmentation is why stars naturally form in clusters. And
Speaker 3: this perfectly explains the forty one percent pairing rate of
Speaker 3: the heavyweights, because.
Speaker 2: They form together out of the same dense, chaotic clump of.
Speaker 3: Material exactly, and they simply never left each other's gravitational grip.
Speaker 3: They were born as a bound pack.
Speaker 2: So where do the lightweights, the brown dwarfs, fit into
Speaker 2: that chaotic cloud.
Speaker 3: Well, the first theory is the ejection.
Speaker 2: Hypothesis, ejection getting kicked out right.
Speaker 3: It proposes that brown dwarfs start forming just like their
Speaker 3: massive siblings within these dense, crowded fragments of the molecular cloud.
Speaker 2: Okay, but because they.
Speaker 3: Are forming in an environment alongside much heavier, much faster
Speaker 3: growing stars, the gravitational tug of war is incredibly viol.
Speaker 2: So there are the runts of the litter getting pushed around.
Speaker 3: Basically, before the brown dwarf can gather enough gas to
Speaker 3: reach the critical mass for fusion, the heavier stars gravitationally
Speaker 3: bully it debiliate through complex orbital interactions, the massive stars
Speaker 3: slingshot the tiny brown dwarf, violently ejecting it from the
Speaker 3: multi star system entirely.
Speaker 2: So they were part of the complex watch gears for
Speaker 2: just this brief chaotic moment, but got stripped out and
Speaker 2: flung into the.
Speaker 3: Void exactly under the ejection hypothesis, their isolation is the
Speaker 3: result of a violent eviction.
Speaker 2: Brutal What's the other theory?
Speaker 3: The competing theory argues for isolated formation, which.
Speaker 2: Means they were alone from the start.
Speaker 3: Right, this model suggests that the immense molecular cloud also
Speaker 3: contains very tiny, isolated, extremely low mass pockets of gas
Speaker 3: on the fringes.
Speaker 2: So away from the dense chaotic center.
Speaker 3: Yes, a brown dwarf forms from one of these tiny
Speaker 3: pockets entirely on its own. It was borne alone in
Speaker 3: a quiet, isolated environment with barely enough material to scrape.
Speaker 2: By scraping together whatever gas it could find. The census
Speaker 2: data showing a nine percent pairing rate feels like a
Speaker 2: massive clue here.
Speaker 3: It strongly limits the theoretical models. I mean, the fact
Speaker 3: that ninety one percent of these lightweights are flying solo
Speaker 3: in our ten parsec bubble heavily suggests that whatever mechanism
Speaker 3: creates them, whether it is violent injection or isolated formation,
Speaker 3: is incredibly efficient at leaving them alone.
Speaker 2: It's so cool how this works. The local census essentially
Speaker 2: acts as a forensic time machine. It allows astrophysicists to
Speaker 2: test the mathematical models of star formation from billions of
Speaker 2: years ago against the reality of our current neighborhood.
Speaker 3: It really grounds the abstract theories and hard data.
Speaker 2: And that perfectly transitions into the actual mechanics of how
Speaker 2: these surviving relationships operate. Because we know the mass rules,
Speaker 2: we know the structures, but the orbital physics within these
Speaker 2: systems are pushed to absolute logic, defying extreme.
Speaker 3: Oh, the extremes are mind boggling.
Speaker 2: Right the time it takes for these stars to complete
Speaker 2: one full lap around each other, their orbital period varies
Speaker 2: wildly depending in the system, immensely. On one extreme, you
Speaker 2: have tightly bound pairs that whip completely around each other
Speaker 2: in a matter of days. I mean, imagine a planetary
Speaker 2: year lasting seventy two hours.
Speaker 3: You'd have a birthday twice a week.
Speaker 2: Right. But then on the far opposite extreme, you have
Speaker 2: stars so widely separated that a single orbit takes tens
Speaker 2: of millions of years.
Speaker 3: And dealing with those extremely wide binaries presents one of
Speaker 3: the most massive observational challenges in all of astronomy.
Speaker 2: I bet, I mean the tight orbits are easy to comprehend.
Speaker 2: It is like a couple holding hands twenty four to seven.
Speaker 3: You can clearly see they're together.
Speaker 2: Exactly, they are inseparable. A single glance tells you they
Speaker 2: are bound together. But a wide binary with an orbit
Speaker 2: taking twenty million years. That is like a long distance
Speaker 2: relationship maintained by a single text message sent once every millennium.
Speaker 3: That's hilarious, but scientifically accurate.
Speaker 2: If I point a telescope at a wide binary, the
Speaker 2: physical distance between them is staggering. They don't look gravitationally bound.
Speaker 2: They just look like two passing strangers who happen to
Speaker 2: be drifting through the exact same cosmic zip code.
Speaker 3: Well, when an orbital period is measured in the tens
Speaker 3: of millions of years, the curvature of that orbit is
Speaker 3: virtually flat from the perspective of human observation, because.
Speaker 2: We're only seeing a tiny slice of time exactly.
Speaker 3: You are not watching a circle being drawn. You are
Speaker 3: looking at a straight line.
Speaker 2: Wait, if the orbit takes tens of millions of years,
Speaker 2: human history has been around long enough to watch even
Speaker 2: a microscopic fraction of a percent of it happen, not
Speaker 2: even close. I mean Galileo first pointed a telescope at
Speaker 2: the sky a mere four hundred years ago. If we
Speaker 2: cannot wait millions of years to watch the orbit actually curve,
Speaker 2: how can we possibly calculate the binding energy.
Speaker 3: It's a great question.
Speaker 2: How do astronomers definitively prove they are actually tethered together
Speaker 2: by gravity and not just two random stars drifting past
Speaker 2: each other in the.
Speaker 3: The detective work required to prove wide binarias bound relies
Speaker 3: on a concept called common proper motion, and that's combined
Speaker 3: with highly precise kinetic energy calculation.
Speaker 2: Okay, break that down for me, common proper motion.
Speaker 3: Since we cannot observe the orbital curve, we measure velocity
Speaker 3: and direction. Imagine two airplanes flying across the ocean.
Speaker 2: Okay, two planes.
Speaker 3: They are separated by miles, but they are flying in
Speaker 3: the exact same direction at the exact same speed. Even
Speaker 3: if you cannot see a physical tether between them, it
Speaker 3: is mathematically highly improbable that two unrelated planes just happen
Speaker 3: to perfectly match speed and heading over the middle of
Speaker 3: the Atlantic.
Speaker 2: They have to be flying in formation exactly.
Speaker 3: They're part of the same group. The same principle applies
Speaker 3: to stars.
Speaker 2: So they're moving together across the sky.
Speaker 3: Yes, GAIA measures the proper motion of these stars, which
Speaker 3: is how fast and in what direction they are physically
Speaker 3: moving across the backdrop of the galaxy.
Speaker 2: Oh I see if.
Speaker 3: Two widely separated stars share a common proper it is
Speaker 3: a massive red flag that they are associated.
Speaker 2: A red flag in a good way, right.
Speaker 3: But association is not the same as being gravitationally bound.
Speaker 3: They could still be slowly drifting apart. To prove the
Speaker 3: tether actually exists, astronomers have to calculate the system's total
Speaker 3: energy balance.
Speaker 2: Wait, how do you weigh a star you can't touch.
Speaker 2: You need to know their mass to know their gravity right.
Speaker 3: Now, exactly, and we do that through spectroscopy. By analyzing
Speaker 3: the spectrum of light the star emits, we can determine
Speaker 3: its temperature, its composition, and ultimately its mass.
Speaker 2: Light reveals mass. That's so elegant.
Speaker 3: It is so. Once we know the mass of both stars,
Speaker 3: we know exactly how much gravitational pull they exert on
Speaker 3: each other. Then we look at the historical radial velocity
Speaker 3: measurements from the Washington Double.
Speaker 2: Star Catalog to see the push and pull.
Speaker 3: To determine their exact three dimensional velocity relative to each other.
Speaker 2: So we figure out exactly how heavy they are and
Speaker 2: exactly how fast they are moving apart from one another.
Speaker 3: Yes, because every mass generates an escape velocity.
Speaker 2: Escape velocity like a rocket trying to leave Earth the
Speaker 2: speed required for an object to break free of its
Speaker 2: gravitational pull forever.
Speaker 3: Precisely, the researchers painstakingly calculate the kinetic energy of their
Speaker 3: relative motion against the potential energy of their combined gravity.
Speaker 2: So speed versus gravity.
Speaker 3: Exactly if their relative speed is even a fraction lower
Speaker 3: than the escape velocity at that specific distance, the math
Speaker 3: is unequivocal. They cannot escape.
Speaker 2: Wow.
Speaker 3: Even if it takes ten million years for the gravitational
Speaker 3: tether to haul them back around, they are prominently bound.
Speaker 3: The math proves a physical reality that time itself moves
Speaker 3: too slowly for us to witness.
Speaker 2: I love that. I absolutely love how the math reveals
Speaker 2: the invisible mechanics of the universe. It's almost poetic.
Speaker 3: It's what makes astrophysics so rewarding.
Speaker 2: But as incredibly fascinating as a million year orbit or
Speaker 2: a quintuple star system is. These stellar companions are not
Speaker 2: universally celebrated by all this ronomers are They Oh definitely not.
Speaker 2: In fact, if you talk to a planetary scientist, companion
Speaker 2: stars are often described as a massive, absolute.
Speaker 3: Nuisance, a total headache right.
Speaker 2: When we are trying to do one of the most
Speaker 2: important things in modern science hunt for habitable exoplanets, these
Speaker 2: multistar systems become an observational nightmare.
Speaker 3: A hitting companion star is literally the last thing you
Speaker 3: want to uncover in a target system when you are
Speaker 3: searching for a second Earth.
Speaker 2: Why is that? I mean, the sheer physics of multiple
Speaker 2: massive bodies interacting does it just completely ruin the delicate
Speaker 2: data required for exoplanet detection.
Speaker 3: It completely ruins it. To understand why the data is
Speaker 3: so fragile, we have to look at the primary methods
Speaker 3: used to find exoplanets.
Speaker 2: Okay, because we aren't just looking through a telescope and
Speaker 2: seeing a planet.
Speaker 3: No, planets do not generate their own visible light. They
Speaker 3: only reflect the light of their host star. And next
Speaker 3: to the blind and glare of a star, a rocky
Speaker 3: planet like Earth is virtually invisible.
Speaker 2: The firefly and the floodlight again.
Speaker 3: Exactly, so, instead of looking for the planet itself, we
Speaker 3: look for the gravitational influence the planet exerts on its.
Speaker 2: Host star, looking for the footprint instead of the person.
Speaker 3: Right, and the most established method for doing this is
Speaker 3: radial velocity.
Speaker 2: We touched on radio velocity with the catalog data. It
Speaker 2: measures the star moving toward or away from us.
Speaker 3: When applied to planet hunting, radial velocity requires staggering almost incomprehensible.
Speaker 2: Precision because the planet is so small.
Speaker 3: Yes, here is the physical mechanism. Gravity is a two
Speaker 3: way street. When a planet orbits a star, it doesn't
Speaker 3: just circle a stationary object pinned to the fabric of space.
Speaker 3: The planet has mass, so it's gravity tugs back on the.
Speaker 2: Star, so the star is moving too.
Speaker 3: Yes, both the star and the planet orbit that shared
Speaker 3: center of mass, the Berry center, But because the star
Speaker 3: is exponentially heavier than the planet, the Bury center is
Speaker 3: usually located deep inside the star itself.
Speaker 2: It's like a seesaw where a massive adult is sitting
Speaker 2: right next to the fulcrum and a toddler is all
Speaker 2: the way out on the other end.
Speaker 3: That's a perfect visual.
Speaker 2: The adult barely moves, but they do shift just a
Speaker 2: little bit to balance it out.
Speaker 3: Exactly, so the star doesn't trace a wide orbital circle.
Speaker 3: It just wobbles back and forth around that internal Berry center.
Speaker 2: It wobbles.
Speaker 3: As the star wobbles toward Earth, the light waves it
Speaker 3: emits gets slightly compressed, shifting toward the blue end of.
Speaker 2: The spectrum blue shift yes.
Speaker 3: And as it wobbles away, the light waves stretch out,
Speaker 3: shifting toward the red end.
Speaker 2: Red shift like a police siren changing pitch as it
Speaker 2: drives past you.
Speaker 3: The exact same principle, but with light instead of sound.
Speaker 3: Astronomers measure these microscopic color shifts to prove an unseen
Speaker 3: planet is pulling.
Speaker 2: On the star. The scale of this measurement is what
Speaker 2: just completely blows my mind. I mean, looking for a massive,
Speaker 2: Jupiter sized planet is one thing. That's a big toddler.
Speaker 3: On the seaside, right, it creates a big wobble.
Speaker 2: But looking for a small, rocky, potentially habitable Earth like
Speaker 2: planet using radial velocity, that's like try to listen to
Speaker 2: a mouse's heartbeat through a stethoscope.
Speaker 3: It's incredibly faint.
Speaker 2: The signal is so delicate. A planet the mass of
Speaker 2: Earth barely moves our Sun at all. It induces a
Speaker 2: wabble of maybe nine centimeters per.
Speaker 3: Second, which is what the speed of a slow crawl.
Speaker 2: Yeah, a slow crawl. Trying to measure a star moving
Speaker 2: at nine centimeters per second from thirty light years away
Speaker 2: is an absolute triumph of human engineering.
Speaker 3: It's a miracle. We can do it at.
Speaker 2: All, but if that star has a companion star. A
Speaker 2: companion star is like someone standing right next to you
Speaker 2: while you have that stethoscope pressed to the mouse and
Speaker 2: they just start blasting a heavy metal concert out of
Speaker 2: a stadium speaker.
Speaker 3: The heavy metal concert completely drowns out the mouse. Every time,
Speaker 3: the gravitational tug of war inflicted by an entire other star,
Speaker 3: even a small red dwarf, completely warps the radial velocity
Speaker 3: readings because.
Speaker 2: The star is being yanked around so violently by the
Speaker 2: stellar companion that you could never ever detect the gentle
Speaker 2: centimeter per second PUG of an Earth sized planet hiding
Speaker 2: in the same system.
Speaker 3: The data is entirely polluted by gravitational noise.
Speaker 2: So radio velocity is completely off the table. For these
Speaker 2: multi star systems. We just can't use it.
Speaker 3: It's useless there.
Speaker 2: But the future of exoplanet hunting is moving beyond just
Speaker 2: detecting shadows and wabbles, isn't it? Oh very much so,
Speaker 2: we are entering an era where astronomers want to actually
Speaker 2: see the planets. The next generation of space observatories is
Speaker 2: currently being designed and funded as we speak.
Speaker 3: It's a very exciting time.
Speaker 2: The heavy hitters coming down the pipeline are NASA's Habitable
Speaker 2: World's Observatory known as HWO, and the European Space Agency's
Speaker 2: larger Interferometer for exoplanets or life.
Speaker 3: These observatories represent the absolute pinnacle of astronomical ambition.
Speaker 2: They really do. Their primary mission is monumental. They're specifically
Speaker 2: designed to directly image and earth analog, which.
Speaker 3: Means they want to physically capture the photons bouncing off
Speaker 3: a rocky habitable zone planet.
Speaker 2: Direct imaging, no more inferring a planet exists through gravity,
Speaker 2: your shadows. Just pointing a massive camera into space, blocking
Speaker 2: out the star and taking a picture of a.
Speaker 3: Blue dot exactly. And the mechanism they use to block
Speaker 3: the star is called a coronagraph.
Speaker 2: A coronagraph how does that work?
Speaker 3: It is essentially a highly engineered physical mask inside the
Speaker 3: telescope that perfectly eclipses the primary stars light. By blocking
Speaker 3: the blinding floodlight, it allows the incredibly faint light from
Speaker 3: any orbiting planets to become visible.
Speaker 2: It's like putting your thumb over the Sun so you
Speaker 2: can see a bird flying past.
Speaker 3: That's a great everyday example. However, the stakes for this
Speaker 3: kind of observation are almost unquantifiable because of the cost.
Speaker 3: Telescope time for observatories of this magnitude is one of
Speaker 3: the most expensive and fiercely contested resources in human history.
Speaker 3: We're talking about billions of dollars of engineering and decades
Speaker 3: of planning.
Speaker 2: Think about the tax dollars and the sheer human effort
Speaker 2: poured into a project like HWO. I mean, as a listener,
Speaker 2: your tax dollars are likely helping fund this pursuit right now.
Speaker 2: The pressure to point that multi billion dollar lens at
Speaker 2: the correct target is immense.
Speaker 3: It is because to get a direct image of an
Speaker 3: Earth analog, these observatories cannot just snap a quick photo
Speaker 3: like a smartphone.
Speaker 2: It's not a point and shoot.
Speaker 3: No, the target planet is so dim billions of times
Speaker 3: dimmer than the star, that the telescope will need to
Speaker 3: lock on and stare at a promising candidate system four
Speaker 3: weeks at a time.
Speaker 2: Weeks.
Speaker 3: It takes weeks of constant observation to gather enough individual
Speaker 3: photons to slowly build a single workable image of the planet.
Speaker 2: Weeks of staring at one single spot in the sky.
Speaker 2: So if you dedicate three weeks of multi billion dollar
Speaker 2: telescope time to a star system, and you unknowingly target
Speaker 2: a star that has a hidden, widely separated companion in
Speaker 2: the background, it.
Speaker 3: Would be an unmitigated disaster for the observation.
Speaker 2: The whole thing is ruined.
Speaker 3: Oh absolutely. If there is a hidden companion star sitting
Speaker 3: just outside the edge of the coronagraph's mask, the background
Speaker 3: light noise the glare from that companion would completely wash
Speaker 3: out the delicate, sparse photons arriving from.
Speaker 2: The exoplanet just to wash a white noise.
Speaker 3: The resulting data would be utterly ruined. The researchers would
Speaker 3: have wasted the most valuable scientific time off the planet
Speaker 3: staring at light pollution.
Speaker 2: Oh man, that hurts to even think about. But this
Speaker 2: begs the entire purpose of the Cosmic Sensus into brilliant
Speaker 2: sharp focus, doesn't it. It does. This massive effort to
Speaker 2: map four hundred and twenty four objects in our ten
Speaker 2: Parsik bubble is not just about cataloging stars for the
Speaker 2: sake of having a list.
Speaker 3: No, it's highly practical.
Speaker 2: It is essentially a highly vetted do not call list
Speaker 2: for these future mega telescopes.
Speaker 3: That's the perfect term for it.
Speaker 2: It is a precise target map that tells HWO and
Speaker 2: life exactly where it is mathematically safe to look.
Speaker 3: It is the ultimate filtering mechanism. By painstakingly identifying the
Speaker 3: two hundred and fifteen bound objects and cataloging the ninety
Speaker 3: two multiple star systems, the researchers have instantly identified which
Speaker 3: stars have a high probability of polluting direct imaging data.
Speaker 2: With either light, noise or chaotic gravity exactly.
Speaker 3: The telescope operators can confidently cross those systems off the
Speaker 3: primary target list.
Speaker 2: The paradox of this research is just brilliant to me.
Speaker 2: I mean, we spend all this incredible effort combining decades
Speaker 2: of the Washington Double Star catalog with the cutting edge
Speaker 2: astrometry of Gaya, calculating complex binding energies for a million
Speaker 2: year orbits, and mapping four hundred and twenty four objects
Speaker 2: down to their precise coordinates, largely so we know exactly
Speaker 2: which ones to ignore.
Speaker 3: I know it sounds counterintuitive, but in the realm of
Speaker 3: high stakes astronomy, eliminating false positives is just as vital
Speaker 3: as identifying a prime target.
Speaker 2: You have to clear the brush right.
Speaker 3: If you are searching for a needle in a massive
Speaker 3: cosmic haystack. The most efficient strategy you can employ is
Speaker 3: to aggressively and systematically burn away all the hay that
Speaker 3: you know definitively does not contain a needle.
Speaker 2: Burn the hay.
Speaker 3: By clearing the board of these multi star systems, we
Speaker 3: can focus all our precious limited observational ress on the quiet, stable, isolated.
Speaker 2: Stars, the loaners, the stars drifting through the galaxy, completely.
Speaker 3: Unattached stars exactly like our sun.
Speaker 2: Let's pull all these threads together to see the complete
Speaker 2: picture of our cosmic neighborhood. Because we started by drawing
Speaker 2: a mathematical boundary, a perfect thirty two point six light
Speaker 2: year sphere around our solar system, just to ensure absolute.
Speaker 3: Completeness, and inside that ten parsk neighborhood, we analyzed four
Speaker 3: hundred and twenty four.
Speaker 2: Objects, and we discovered that our human bias is completely wrong.
Speaker 2: Roughly half the neighborhood is actually paired up.
Speaker 3: It's a busy street, it is.
Speaker 2: We learned that mass dictates relationship status. Right with massive
Speaker 2: stars thriving in complex, double, triple and even intricately layered
Speaker 2: quintuple systems.
Speaker 3: The Swiss watches of the galaxy.
Speaker 2: Exactly while the tiny brown dwarfs remain isolated, likely due
Speaker 2: to violent injections early in their formation.
Speaker 3: The outcasts.
Speaker 2: We explored the dizzying extremes of orbital physics, from pairs
Speaker 2: whipping around each other in days to wide binaries tethered
Speaker 2: together across tens of millions of years by invisible, calculatingly
Speaker 2: precise gravitational bond.
Speaker 3: And ultimately we uncovered why this definitive map is so
Speaker 3: critical right.
Speaker 2: It clears the literal and figurative noise. It provides our
Speaker 2: next generation telescopes like HWO and Life with a clean,
Speaker 2: pristine roadmap to hunt for a second Earth by actively
Speaker 2: avoiding the chaotic heavy metal concerts of multiple Star systems.
Speaker 3: It is a remarkable achievement that fundamentally changes our perception
Speaker 3: of our local environment. It transforms a mysterious chaotic void
Speaker 3: into a meticulously mapped, understood terrain.
Speaker 2: We now know the layout of the neighborhood we do.
Speaker 2: It is the foundation for everything that comes next. And
Speaker 2: as we wrap up this exploration, I want to leave
Speaker 2: you with a final lingering thought. Tom all over, Okay,
Speaker 2: when we look up at our lone, companionless sun, it
Speaker 2: is really easy to feel a sense of profound isolation.
Speaker 2: We feel like we're just drifting through the dark, empty
Speaker 2: space of the Milky Way, entirely by ourselves, disconnected from
Speaker 2: the cosmic dance happening all around us.
Speaker 3: It can feel very lonely.
Speaker 2: But given everything we've just unpacked, given how violently companion
Speaker 2: stars warp the gravitational environment, given how they flood a
Speaker 2: solar system with blinding light noise, and given how inherently
Speaker 2: hostile a multi star system is to the delicate formation
Speaker 2: of a planet, think about what that implies for our
Speaker 2: very existence.
Speaker 3: The silence is the point.
Speaker 2: If human ingenuity ever does pinpoint a perfect, tranquil, alternative
Speaker 2: Earth nearby, a world where life has had the billions
Speaker 2: of years of uninterrupted quiet necessary to evolve, it will
Speaker 2: almost certainly be orbiting a star just as lonely as ours.
Speaker 3: The visual spectacle of a multi star system with five
Speaker 3: suns in the sky might be breathtaking.
Speaker 2: From a distance, it'll be stunning that.
Speaker 3: That sheer chaos is fundamentally incompatible with the fragile, steady
Speaker 3: development of a habitable world.
Speaker 2: So perhaps our sun's isolation isn't some tragic cosmic anomaly.
Speaker 2: It isn't something to feel lonely or adrift about. Maybe
Speaker 2: being a lone star is the precise, absolutely necessary prerequisite
Speaker 2: for life.
Speaker 3: Our requirement, not a bug.
Speaker 2: The quiet solitude of our single sun's sky isn't a
Speaker 2: flaw in our solar system's design. It is the exact
Speaker 2: tranquil reason we are here, sitting on this porch, able
Speaker 2: to look up at the sky and wonder about the
Speaker 2: universe in the first place.