Einstein’s Law and the Dearth of Two-Sun Planets

<v Speaker 1>Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
<v Speaker 1>with our soothing Bedtime a Strombie podcast. Each episode offers
<v Speaker 1>a gentle journey through the stars, planets, and beyond, perfect
<v Speaker 1>for unwinding after a long day. Let's travel through the
<v Speaker 1>mysteries of the universe as you drift off into a
<v Speaker 1>peaceful slumber under the night sky.
<v Speaker 2>I want you to take a moment and just visualize.
<v Speaker 2>Go back to when you were a kid, or maybe
<v Speaker 2>even last week. If you're a nerd like me. You're
<v Speaker 2>sitting in a dark theater or maybe on your couch.
<v Speaker 2>You're watching one of the most famous scenes in cinema history.
<v Speaker 2>A young farm boy, frustrated stuck on a desert planet,
<v Speaker 2>walks out at his iglu house, kicks at the dust
<v Speaker 2>and looks at the horizon.
<v Speaker 3>I know exactly where you are. You're on Tatooine.
<v Speaker 2>I am on Tattooine. And he looks up and the
<v Speaker 2>music swells that John Williams score kicks in and he
<v Speaker 2>sees not one but two suns setting a binary sunset,
<v Speaker 2>one red, one white, dipping below the dunes.
<v Speaker 3>It is iconic. It's one of those images that's just
<v Speaker 3>burned into our collective cultural memory.
<v Speaker 2>It is iconic. But more than that, it felt real.
<v Speaker 2>It sold an entire generation on it, this idea that
<v Speaker 2>the universe is this exotic, romantic place where having two
<v Speaker 2>shadows is just a normal Tuesday. It promised us that
<v Speaker 2>out there, in the billions of stars in our galaxy
<v Speaker 2>there are worlds that break the rules of our boring,
<v Speaker 2>single sun existence.
<v Speaker 3>It's a beautiful promise, and scientifically, at the time and
<v Speaker 3>even now, it makes a lot of intuitive sense. I mean,
<v Speaker 3>we know binary star systems where two stars are locked
<v Speaker 3>in a gravitational dance, are incredibly common. Some estimates say
<v Speaker 3>maybe half of all sun like stars are in pairs.
<v Speaker 2>Right, so you think, naturally, if you just stand on
<v Speaker 2>a rock orbiting those stars, you'd see that double sunset.
<v Speaker 3>It feels like it should be the norm. If half
<v Speaker 3>the stars are couples, half the planet should be watching
<v Speaker 3>them dance.
<v Speaker 2>But and you know, there's a massive butt coming. Because
<v Speaker 2>we are sitting here today, there is Reality is effectively
<v Speaker 2>room our sci fi dreams.
<v Speaker 3>Reality has a habit of doing that. It's a little
<v Speaker 3>less romantic and a lot more chaotic.
<v Speaker 2>Astronomers have been hunting for these worlds. They have been
<v Speaker 2>scanning the heavens with the most powerful eyes humanity has
<v Speaker 2>ever built. Kepler tests James Webb, we found thousands of planets.
<v Speaker 2>We have a catalog of worlds that is bursting at
<v Speaker 2>the seams. But when it goes to finding a real
<v Speaker 2>life tattooine, it's not just difficult, it's starting to look
<v Speaker 2>like a ghost town.
<v Speaker 3>It is a genuine astronomical mystery. We aren't just talking
<v Speaker 3>about bad luck in the search or pointing the telescope
<v Speaker 3>the wrong way. We're seeing a statistically significant absence avoid
<v Speaker 3>where planets should be.
<v Speaker 2>So the question we are tackling in this exploration is
<v Speaker 2>where are they. We have the stars, we have the
<v Speaker 2>technology to see them, but the planets are missing, and
<v Speaker 2>today we are going to find out why. And the
<v Speaker 2>answer the answer is honestly one of the most surprising
<v Speaker 2>twists I've encountered in astrophysics. It turns out the culprit
<v Speaker 2>this planetary disappearance isn't some random cosmic event. It's not
<v Speaker 2>alien strip mining the galaxy. It's a guy named Albert Einstein, or.
<v Speaker 3>To be more precise, the fundamental laws of physics that
<v Speaker 3>Einstein uncovered more than a century ago general relativity.
<v Speaker 2>Which is wild to me. I usually think of Einstein's
<v Speaker 2>general theory of relativity as this high concept, blackboard filling
<v Speaker 2>theory that explains black holes or the bending of light
<v Speaker 2>around massive galaxy clusters, you know, cosmic scale stuff. I
<v Speaker 2>don't think of it as a planetary exterminator.
<v Speaker 3>And that is the fascinating twist we are unpacking today.
<v Speaker 3>It turns out that general relativity doesn't just govern the
<v Speaker 3>shape of the universe on a grand scale. It creates
<v Speaker 3>a very specific, very ruthless mechanism inside binary star systems.
<v Speaker 3>It acts almost like a cosmic broom, sweeping planets out
<v Speaker 3>of existence.
<v Speaker 2>Sweeping planets out of existence. Okay, that is an ominous image.
<v Speaker 2>It sounds like a villain's weapon in a movie.
<v Speaker 3>It does, doesn't it. And up until extremely recently, I
<v Speaker 3>mean we're talking about a paper published just last month
<v Speaker 3>in the Astrophysical Journal Letters, with news really breaking on
<v Speaker 3>this around January thirty, twenty twenty six, we didn't fully
<v Speaker 3>understand how effective this broom was. We suspected gravity was messy,
<v Speaker 3>but we didn't know it was this precise, this cutting
<v Speaker 3>edge stuff.
<v Speaker 2>We're looking at the ink still drying on the paper.
<v Speaker 3>Absolutely, this comes from researchers Mohammed Farhat at the University
<v Speaker 3>of California, Berkeley and Jihatuma at the American University of Beirut.
<v Speaker 3>They've done the heavy lifting, the math, the simulations, and
<v Speaker 3>they found the smoking gun.
<v Speaker 2>Our mission today is to walk through that investigation. We're
<v Speaker 2>going to look exactly how gravity goes rogue in these systems.
<v Speaker 2>We're going to define this terrifying concept called the instability zone,
<v Speaker 2>which is just great branding for a region a space,
<v Speaker 2>and we're going to explain why this discovery solves a
<v Speaker 2>puzzle that has been bugging astronomers for decades.
<v Speaker 3>It is a story about gravity resonance and the delicate,
<v Speaker 3>often violent dance of orbital mechanics, and ultimately it shows
<v Speaker 3>us that solar systems are much more fragile than we
<v Speaker 3>like to believe.
<v Speaker 2>All right, So before we get to the destruction, let's
<v Speaker 2>establish the baseline. Let's look at the crime scene. We
<v Speaker 2>need to understand just how rare these planets are. Because
<v Speaker 2>I feel like I hear about new planet discoveries constantly,
<v Speaker 2>New Super Earth, New Ocean world. It feels like we
<v Speaker 2>are tripping over planets.
<v Speaker 3>You're not wrong. We are living in what historians will
<v Speaker 3>probably call the golden age of exoplanet discovery, thanks to
<v Speaker 3>missions like NASAs Kepler Space Telescope and tests that's the
<v Speaker 3>Transiting Exoplanet Survey satellite. We have confirmed over six thousand
<v Speaker 3>extrasolar planets.
<v Speaker 2>Six thousand. That is a robust data set. That's not
<v Speaker 2>a handful of anomalies. That's a census exactly.
<v Speaker 3>It's a huge population. We have gas giants, hot jupiters,
<v Speaker 3>rocky worlds, mini neptunes. We have a zoo of planets.
<v Speaker 3>Here's the number that stops you in your tracks. Out
<v Speaker 3>of those more than six thousand planets, do you know
<v Speaker 3>how many are confirmed to be transiting circumbinary planets, meaning
<v Speaker 3>planets that orbit two stars at once.
<v Speaker 2>Okay, if binary stars are half the sky, i'd expect hundreds,
<v Speaker 2>maybe one thousand. It is fourteen fourteen. Wait one four
<v Speaker 2>like a dozen and two extra fourteen. So okay, that
<v Speaker 2>doesn't seem right. That seems impossibly low. You said binary
<v Speaker 2>stars are common. Are we just bad at looking at them?
<v Speaker 3>That's the first question everyone asks, Well, let's look at
<v Speaker 3>the statistics. Most stars form in pairs the Sun is
<v Speaker 3>actually a bit of an odd ball for being single.
<v Speaker 3>So when Kepler was looking at its patch of the sky,
<v Speaker 3>it wasn't avoiding binaries. It found about three thousand eclipsing
<v Speaker 3>binary star systems just in its survey patch.
<v Speaker 2>Okay, so we have a sample size of three thousand
<v Speaker 2>potential landlords, three thousand binary couples that could be hosting.
<v Speaker 3>Tenants exactly, and we know from looking at single stars
<v Speaker 3>like our Sun, that about ten percent of them host
<v Speaker 3>massive planets. That's a rough rule of thumb in astronomy.
<v Speaker 3>So statistically, if nature plays by the same rules everywhere,
<v Speaker 3>if planet formation is just something that happens around stars,
<v Speaker 3>regardless of how many there are.
<v Speaker 2>Then we should expect about ten percent of those binary
<v Speaker 2>systems to have plant too, it thinks. So, so ten
<v Speaker 2>percent of three thousand, Yeah, we should have seen about
<v Speaker 2>three hundred tattoos precisely.
<v Speaker 3>We expected three hundred. We found fourteen.
<v Speaker 2>That is a massive deficit. That's not a rounding error,
<v Speaker 2>that's a where did everyone go? Situation. That's a ninety
<v Speaker 2>five percent missing person's rate.
<v Speaker 3>It's staggering. It's one of the biggest discrepancies we have
<v Speaker 3>in exoplanet science, and it gets even more stark when
<v Speaker 3>you look at a specific type of binary system. The
<v Speaker 3>researchers far Hot and Tuma focus their study on what
<v Speaker 3>we call tight binaries.
<v Speaker 2>Tight binaries, I assume that means the stars are physically close.
<v Speaker 3>Together, very close. These are pairs of stars that orbit
<v Speaker 3>each other in seven days or less.
<v Speaker 2>Whoa hold on seven days? Imagine that two sons whipping
<v Speaker 2>around each other in a week. That is incredibly fast.
<v Speaker 2>The Earth takes three hundred and sixty five days to
<v Speaker 2>go around the Sun. These entire stars are doing a
<v Speaker 2>deucydew in a week.
<v Speaker 3>It is incredibly fast and incredibly close. The gravitational forces
<v Speaker 3>there are intense. Now Here is the kicker. These are
<v Speaker 3>the systems where it should be easiest to find planets.
<v Speaker 2>Why is that? Why would it be.
<v Speaker 3>Easier there because of the geometry. Since the stars are
<v Speaker 3>orbiting so fast, they are constantly eclipsing each other from
<v Speaker 3>our point of view. That's how Kepler and Tess find
<v Speaker 3>a lot of these systems to begin with. Okay, so
<v Speaker 3>if there was a planet orbiting them, the likelihood of
<v Speaker 3>it also passing in front of those stars transitting is
<v Speaker 3>relatively high because the whole system is aligned flat like
<v Speaker 3>a pancake. We should be seeing shadows constantly, right.
<v Speaker 2>It's all lined up for us. So we have the
<v Speaker 2>perfect setup, high visibility, lots of targets. So what's the
<v Speaker 2>count for planets around these tight seven day binaries?
<v Speaker 3>Zero?
<v Speaker 2>Zero, none at all, not even one weird.
<v Speaker 3>Outlier, not a single confirmed one. Mohammed Farhat, the lead researcher,
<v Speaker 3>was very blunt about this. He called it an absolute desert.
<v Speaker 2>An absolute desert that is haunting. It's like arriving at
<v Speaker 2>a bustling city or what you thought was the city
<v Speaker 2>and finding out the buildings are just facades and nobody
<v Speaker 2>lives there.
<v Speaker 3>And that is the mystery. Why why is there a desert?
<v Speaker 3>These systems have plenty of mass, they have the raw materials,
<v Speaker 3>the dust and gas to form planets. We shouldn't be
<v Speaker 3>seeing a zero. We should be seeing a bustling neighborhood.
<v Speaker 2>And this is where the new research comes in because
<v Speaker 2>for a long time, the assumption was just that maybe
<v Speaker 2>planet formation was hard in these systems, like maybe the
<v Speaker 2>gravity of two stars just prevented dust from turning into rocks,
<v Speaker 2>like trying to build a sand castle in a Blender.
<v Speaker 3>That was a leading theory. It's called formation inhibition, the
<v Speaker 3>idea that the turbulence is just too high to let
<v Speaker 3>a planet grow, but far hoten to more realize that
<v Speaker 3>planets probably do form. The physics of formation suggests you
<v Speaker 3>can still get planets a bit further out. They form,
<v Speaker 3>They just don't stay there.
<v Speaker 2>They don't stay there. Okay, so now we're getting into
<v Speaker 2>the mechanics of the eviction. Notice, to understand how a
<v Speaker 2>planet gets kicked out, we first need to really understand
<v Speaker 2>the house it's living in. We need to visualize the movement.
<v Speaker 2>Walk me through the choreography of a binary system.
<v Speaker 3>Right, let's build a mental model. Visualize two stars usually
<v Speaker 3>similar in mass, though not always identical, and they are
<v Speaker 3>orbiting a common center of gravity a point in space
<v Speaker 3>between them. But here is the critical detail. Their orbit
<v Speaker 3>isn't a perfect circle.
<v Speaker 2>Nature rarely does perfect circles. It's always a little messy.
<v Speaker 3>Exactly. It's an ellipse. It's egg shaped, so sometimes the
<v Speaker 3>stars are closer together, sometimes further apart.
<v Speaker 2>Okay, I've got two egg shaped orbits dancing around a
<v Speaker 2>center point.
<v Speaker 3>Now Here is the first key concept, precession. This entire
<v Speaker 3>egg shaped orbit isn't static. It doesn't stay painted on
<v Speaker 3>the backdrop of space. The ellipse itself rotates over time.
<v Speaker 2>I think we need to break this down. Precession is
<v Speaker 2>one of those physics words that gets thrown around, But
<v Speaker 2>what does it actually look like.
<v Speaker 3>The best analogy, and the one the researchers use, is
<v Speaker 3>a spinning top.
<v Speaker 2>Okay, a top. We've all spin a top.
<v Speaker 3>You spin a top on a table. It spins fast, right,
<v Speaker 3>that's the rotation. But as it spins, look at the
<v Speaker 3>handle the axis. It doesn't just point straight up. It
<v Speaker 3>slowly traces a circle in the air. It wobbles right.
<v Speaker 2>That slows circular wobble of the handle.
<v Speaker 3>That is precession in the case of the stars. Imagine
<v Speaker 3>drawing that egg shaped orbit on a piece of paper.
<v Speaker 3>Then put a pin in the center and slowly spin
<v Speaker 3>the paper. The shape of the orbit the egg stays
<v Speaker 3>the same, but the direction the pointy end of the
<v Speaker 3>egg is pointing changes. It sweeps around in a circle.
<v Speaker 2>Got it. So the stars are orbiting each other fast,
<v Speaker 2>but the track they're running on is slowly rotating exactly.
<v Speaker 3>That is the ubsidal procession of the binary. Now, keep
<v Speaker 3>that wobble in mind, because there's a second thing happening
<v Speaker 3>in these tight binaries. The stars are getting closer.
<v Speaker 2>Why if they're in orbit, shouldn't they stay.
<v Speaker 3>There in a perfect world, Yes, but these are massive
<v Speaker 3>fluid bodies, they're not solid points. Just like the Moon
<v Speaker 3>pulls on the Earth's oceans to create tides, these two
<v Speaker 3>stars are pulling on each other. They raise huge tidal
<v Speaker 3>bulges on each other's surfaces.
<v Speaker 2>Like a constant stretching.
<v Speaker 3>Yes, and because they are spinning and orbiting, that stretching
<v Speaker 3>creates friction. Frushon generates heat, and heat is energy leaving
<v Speaker 3>the system. When an orbit loses energy, it shrinks.
<v Speaker 2>So they are spiraling inward slowly.
<v Speaker 3>I mean this takes tens of millions of years, but
<v Speaker 3>on Cozak time scales, that's pretty fast. They are spiraling
<v Speaker 3>in So put it all together, we have an egg
<v Speaker 3>shaped orbit that is wobbling, processing like a top, and
<v Speaker 3>simultaneously shrinking due to tidal friction.
<v Speaker 2>Okay, that's the stars. That's the dynamic duo in the center.
<v Speaker 2>It's a complex dance. Now let's throw a planet into
<v Speaker 2>the mix.
<v Speaker 3>Where is it The planet is orbiting both of them
<v Speaker 3>much further out, it's doing a big loop around the
<v Speaker 3>pair to the planet. The two stars almost look like
<v Speaker 3>one heavy object, but not quite. And here's where the
<v Speaker 3>conflict begins. The planet's orbit also processes. It also wobbles.
<v Speaker 2>Okay, so everything is wobbling. The stars are wobbling, the
<v Speaker 2>planet is wabbling. Why is that a problem? Usually in
<v Speaker 2>physics things just settle into a groove.
<v Speaker 3>The problem, and this is the crux of the new discovery,
<v Speaker 3>is why they are wobbling. There are two different sets
<v Speaker 3>of laws running the show here.
<v Speaker 2>This is the Newton versus Einstein's showdown.
<v Speaker 3>It is the planet is far away. Its wobble is
<v Speaker 3>driven by standard Newtonian mechanics. It feels the gravitational tug
<v Speaker 3>of the two stars as a lump of mass, and
<v Speaker 3>that quadrupole moment causes its orbit to rotate. It's simple
<v Speaker 3>classical physics. It's what we learn in undergrad.
<v Speaker 2>Okay, Newton is driving the planet. Who is driving the stars?
<v Speaker 3>Einstein specifically general relativity.
<v Speaker 2>This is where we need to really dig in because
<v Speaker 2>usually for things like planets, Newton is good enough. Right
<v Speaker 2>MASSI used Newton to get to the Moon. They didn't
<v Speaker 2>need a relativity calculator for Apollo eleven.
<v Speaker 3>They did not, But Apollo eleven wasn't navigating two massive
<v Speaker 3>suns whipping around each other in seven days. When you
<v Speaker 3>have that much mass moving that fast, the gravity is intense.
<v Speaker 3>The warping of space time becomes significant.
<v Speaker 2>Give me the Einstein visual How is this different from
<v Speaker 2>just pulling?
<v Speaker 3>The classic analogy is the trampoline. Imagine a bowling ball
<v Speaker 3>sitting on a trampoline. It curves the fabric right.
<v Speaker 2>Right, It makes a big dip.
<v Speaker 3>And if you roll a marble past it, the marble
<v Speaker 3>curves because the surface is curved. That's the standard gravity visualization. Okay, Now,
<v Speaker 3>imagine two bowling balls spinning around each other in the
<v Speaker 3>middle of that trampoline. They aren't just sitting there. They
<v Speaker 3>are dragging the fabric with them. They are churning the canvas.
<v Speaker 3>They create what's called a frame dragging effect.
<v Speaker 2>It's like mixing better exactly.
<v Speaker 3>This warping of space time, this churning causes the star's
<v Speaker 3>orbit to process much faster than Newton would predict. If
<v Speaker 3>you only use Newton's math, you'd get the wrong answer
<v Speaker 3>for how fast that egg is rotating. You need Einstein's correction.
<v Speaker 2>Okay, so the stars are wabbling fast because of Einstein's
<v Speaker 2>bent space time. The planet is wobbling slowly because of
<v Speaker 2>Newton's simple gravitational tug.
<v Speaker 3>Correct. And here is the mechanism that far Hot and
<v Speaker 3>Tuma identified. As the stars spiral closer together due to
<v Speaker 3>those tidal forces we mentioned. As the orbit shrinks, the
<v Speaker 3>relativistic effects get stronger. The stars get deeper into that
<v Speaker 3>gravity well, the warping gets more intense, so the star's
<v Speaker 3>procession speeds up.
<v Speaker 2>The central wabble gets faster.
<v Speaker 3>Yes, but think about the planet. As the stars get
<v Speaker 3>closer together, they look more and more like a single
<v Speaker 3>point to the distant planet. The leverage they have on
<v Speaker 3>the planet's orbit decreases. The Newtonian torque gets weaker, so
<v Speaker 3>the planet's precession slows down.
<v Speaker 2>I see where this is going. It's a graph with
<v Speaker 2>two lines. One is going up the stars are speeding up,
<v Speaker 2>one is going down. The planet is slowing down.
<v Speaker 3>Exactly. Imagine two cars on a racetrack. One is accelerating,
<v Speaker 3>one is breaking. Eventually they are going to hit the
<v Speaker 3>exact same speed for a moment. They're going to cross paths.
<v Speaker 2>And in physics, when two frequencies or rates match. That's
<v Speaker 2>usually when bridges collapse or wineglasses shatter.
<v Speaker 3>It is the biggest deal in dynamics.
<v Speaker 2>It is called resonance, and that resonance, I take it,
<v Speaker 2>is not good news for the planet.
<v Speaker 3>It is a bit of a horror movie for the planet.
<v Speaker 3>This specific type is called a secular resonance.
<v Speaker 2>Okay, let's unpack that moment. What happens when the rate
<v Speaker 2>of the star is wobble matches the rate of the
<v Speaker 2>planet's wobble. Why is matching the rhythm?
<v Speaker 3>So destructive resonance acts like a pump. It accumulates energy.
<v Speaker 3>Think of pushing a child on a swing.
<v Speaker 2>Classic example, everyone's done.
<v Speaker 3>If you push the swing at random times, sometimes when
<v Speaker 3>it's going back, sometimes forward, you just kill the momentum.
<v Speaker 3>Nothing happens. But if you push at the exact moment,
<v Speaker 3>the swing starts to go down. If you match the frequency,
<v Speaker 3>the swing goes higher and higher and higher. You are
<v Speaker 3>adding energy to the system efficiently.
<v Speaker 2>So gravity is pushing the planet's orbit at the exact
<v Speaker 2>right rhythm.
<v Speaker 3>Yes, the gravitational perturbations from the binary stars are kicking
<v Speaker 3>the planet at the exact same point in its procession
<v Speaker 3>cycle over and over and over again, a tiny push
<v Speaker 3>every time, perfectly timed.
<v Speaker 2>And what is the result of that kicking? What does
<v Speaker 2>that do to the orbit?
<v Speaker 3>Eccentricity which means it means the orbit stops being a nice,
<v Speaker 3>safe circle. It gets stretched wildly. Elongated is the description.
<v Speaker 3>The resonance pumps up the ex centricity, meaning the planet
<v Speaker 3>starts swinging way out into deep space and then diving
<v Speaker 3>dangerously close to the suns on the rebound.
<v Speaker 2>It's losing control. It's like a carfish tailing on ice,
<v Speaker 2>getting wider and wider.
<v Speaker 3>Swings completely. It is being destabilized. And remember the stars
<v Speaker 3>are still shrinking their orbit. They don't stop. So this
<v Speaker 3>resonance isn't just a one time bump. It sweeps through
<v Speaker 3>the system. It locks in. As the stars move, they
<v Speaker 3>drag the planet into a more and more chaotic state.
<v Speaker 2>So the planet is swinging wildly, it's getting stretched like
<v Speaker 2>a rubber band, and eventually it must snap.
<v Speaker 3>That leads us to the instability zone.
<v Speaker 2>That is definitely a sci fi term. Captain, we are
<v Speaker 2>entering the instability zone.
<v Speaker 3>It sounds like it, but it's a very real concept.
<v Speaker 3>In orbital dynamics, every binary system has a region around it,
<v Speaker 3>a specific radius where gravity is just too chaotic. It's
<v Speaker 3>a messy three body problem. If you put a rock there,
<v Speaker 3>it won't orbit, it will be thrown around like a
<v Speaker 3>leaf in the wind.
<v Speaker 2>Far Hut, the researcher had a great quote about this
<v Speaker 2>zone regarding planet formation. He said, trying to form a
<v Speaker 2>planet there is like trying to stick snowflakes together in
<v Speaker 2>a hurricane.
<v Speaker 3>It's a perfect image. You just can't build anything stable there.
<v Speaker 3>But here is the tragedy of our tattooines. These planets
<v Speaker 3>didn't form in the hurricane. They formed further out in
<v Speaker 3>the calm waters. They were safe. But this Einstein driven resonance,
<v Speaker 3>this sweeping mechanism we just described, drags the planet's orbit
<v Speaker 3>so that its closest approach, the periastron, dips into the hurricane.
<v Speaker 2>It pushes it into the instability zone.
<v Speaker 3>And once it touches that zone, physics takes over. It's
<v Speaker 3>game over.
<v Speaker 2>What are the options? How does the planet die? I'm
<v Speaker 2>assuming it's not peaceful.
<v Speaker 3>There are two main modes of destruction. Mode one is ejection.
<v Speaker 2>Ejection, just like it sounds.
<v Speaker 3>The planet swings in gets a gravitational kick or a
<v Speaker 3>slingshot assist from one of the stars, and is flung
<v Speaker 3>out of the system entirely. It achieves escape velocity.
<v Speaker 2>It becomes a rogue planet just floating in the dark
<v Speaker 2>between the.
<v Speaker 3>Stars, exactly untethered from any star, just drifting in the
<v Speaker 3>void forever. We think there might be billions of these
<v Speaker 3>room planets floating between the stars. This mechanism might be
<v Speaker 3>one of the factories producing that.
<v Speaker 2>That's depressing frozen in the eternal night. What's option two?
<v Speaker 3>Engulfment. The planet swings too close, the tidal forces from
<v Speaker 3>the stars might shredd it apart into debris, literally ripping
<v Speaker 3>the planet into a ring of dust. Or it might
<v Speaker 3>physically crash into the surface of one of the stars.
<v Speaker 2>So frozen in the void or incinerated in a star.
<v Speaker 3>Those are the choices. Far Hot put it bluntly. In
<v Speaker 3>both cases you get rid of the planet.
<v Speaker 2>And this isn't a rare occurrence in their models, right,
<v Speaker 2>This isn't a one in a million shot. This is
<v Speaker 2>a regular thing.
<v Speaker 3>No, the models are brutal. They ran simulations of thousands
<v Speaker 3>of systems. They calculated that this general relativistic effect disrupts
<v Speaker 3>eight out of every ten planets around these tight binaries.
<v Speaker 2>Eighty percent disruption rate. That's a huge number.
<v Speaker 3>And of those that get disrupted, seventy five percent are
<v Speaker 3>totally destroyed, either ejected or gulfed.
<v Speaker 2>Wow. So if you are a planet born around a
<v Speaker 2>binary star that eventually tightens up, you have a massive
<v Speaker 2>probability of being wiped out.
<v Speaker 3>That explains the desert. We don't see planets there because
<v Speaker 3>the physics of the shrinking binary system effectively cleans the house.
<v Speaker 3>The planets might have formed, They might have been there
<v Speaker 3>for millions of years, but as the stars evolved and
<v Speaker 3>spiraled in the trap was sprum.
<v Speaker 2>It's fascinating because it solves the mystery without needing some
<v Speaker 2>external force. You don't need a passing black hole or
<v Speaker 2>a rogue star to mess things up. The system destroys
<v Speaker 2>itself from the inside out, exactly.
<v Speaker 3>It is a natural consequence of the system's evolution. It's
<v Speaker 3>built into the math of gravity. It's an internal self
<v Speaker 3>destruct mechanism.
<v Speaker 2>Okay, but I have to play devil's advocate here. We
<v Speaker 2>did find fourteen planets. We said at the beginning, there
<v Speaker 2>are fourteen confirmed circumbinary planets. So the room didn't get everyone.
<v Speaker 2>Are they just the luckiest worlds in the galaxy?
<v Speaker 3>In a way? Yes, But their location tells a story.
<v Speaker 3>It confirms the theme rather than debunking it.
<v Speaker 2>Where are they? What's special about their position?
<v Speaker 3>The researchers noted that most of the planets we have found,
<v Speaker 3>specifically the ones around slightly wider binaries, are hovering just
<v Speaker 3>outside the edge of the instability zone.
<v Speaker 2>They're parked right on the cliff edge right.
<v Speaker 3>This suggests that they probably migrated inward from further out,
<v Speaker 3>which planets often do, but they stopped just before they
<v Speaker 3>hit the danger zone. Or more likely, they are the
<v Speaker 3>survivors of a larger population. Maybe there were planets closer
<v Speaker 3>in that got eaten and these ones just happened to
<v Speaker 3>be far enough out to be safe.
<v Speaker 2>So they're the ones that stopped at the last safe
<v Speaker 2>rest stop before the deadly stretch of highway.
<v Speaker 3>That's a great way to put it, And the paper
<v Speaker 3>says for the tightest binaries, the seven day ones, the
<v Speaker 3>count is zero. For those, the resonance mechanism is so
<v Speaker 3>strong that it likely clears everything out to a very
<v Speaker 3>large distance.
<v Speaker 2>So is it impossible for a tattooining to exist around
<v Speaker 2>these tight stars. Could there be a planet way way
<v Speaker 2>out there like a Pluto tattoo?
<v Speaker 3>It is not impossible. In fact, Tuma and far Hot
<v Speaker 3>are confident that planets are there. They just have to
<v Speaker 3>be very far away. If you go far enough out,
<v Speaker 3>the relativistic effects dampen, the resonance doesn't hit as hard,
<v Speaker 3>or it happens at a different point in the system's evolution.
<v Speaker 3>And if they are far away, then we have a
<v Speaker 3>detection problem.
<v Speaker 2>Right. Bring it back to the tools we talked about
<v Speaker 2>Kepler and tests. They use the transit method. They wait
<v Speaker 2>for a planet to cross in front of the star
<v Speaker 2>and block a tiny bit of light.
<v Speaker 3>Think about the geometry. If a planet is close to
<v Speaker 3>the star, it orbits quickly, maybe every few weeks or months.
<v Speaker 3>You get lots of chances to see it block the light,
<v Speaker 3>and the probability of it being aligned with Earth is higher.
<v Speaker 2>But if a planet is way out there.
<v Speaker 3>It might take ten twenty fifty years to complete one orbit,
<v Speaker 3>so you might have to stare at that star for
<v Speaker 3>a century just to catch one transit, and the alignment
<v Speaker 3>has to be absolutely perfect for it to pass between
<v Speaker 3>us and the star. If it's tilted, even a fraction
<v Speaker 3>of a degree, we miss it.
<v Speaker 2>It might not be totally empty. It might just be
<v Speaker 2>that the only survivors are hiding in the dark, too
<v Speaker 2>far away for.
<v Speaker 3>Us to see exactly. As Tuma said, there are surely
<v Speaker 3>planets out there. It's just that they are difficult to
<v Speaker 3>detect with current instruments.
<v Speaker 2>It's a classic case of looking for your keys under
<v Speaker 2>the street light, because that's what the light is. The
<v Speaker 2>keys might be in the bushes, but we can't see them.
<v Speaker 3>That is a perfect analogy. We are seeing the absence
<v Speaker 3>of close planets, which confirms the destruction theory. The distant
<v Speaker 3>ones are safe from the resonance. That's safe from our
<v Speaker 3>telescopes too.
<v Speaker 2>This brings up such an interesting historical connection. We're talking
<v Speaker 2>about Einstein procession and orbits. If you know your history
<v Speaker 2>of science, this rings a bell. This isn't the first
<v Speaker 2>time Einstein showed up to explain a wabble.
<v Speaker 3>It should ring a bell. This is actually a beautiful
<v Speaker 3>full circle moment for physics. It's like poetry.
<v Speaker 2>Take us back to nineteen fifteen or even before that.
<v Speaker 2>What was the problem.
<v Speaker 3>So in the nineteenth century there was a big problem
<v Speaker 3>with the planet Mercury.
<v Speaker 2>Our Mercury, the little scorched rock next to the Sun.
<v Speaker 3>Right led by a guy named Urbane Leverier, who was
<v Speaker 3>a math genius, had mapped Mercury's orbit with extreme precision
<v Speaker 3>using Newton's laws. But it wasn't behaving. The point of
<v Speaker 3>its closest approach to the Sun, the perihelion was moving.
<v Speaker 2>It was precessing, wobbling, just like our binary stars.
<v Speaker 3>Yes, now, Newton's math accounted for most of that wobble
<v Speaker 3>due to the tug of Jupiter and Saturn and the
<v Speaker 3>other planets. But there was a tiny bit left over,
<v Speaker 3>a tiny fraction of a degree forty three arc seconds
<v Speaker 3>per century that Newton couldn't explain, and.
<v Speaker 2>People went crazy trying to fix it. They invented a
<v Speaker 2>fake planet called Vulcan, right inside Mercury's orbit.
<v Speaker 3>They did. Laverier was convinced there must be a hidden
<v Speaker 3>planet inside Mercury's orbit tugging on it. They named it Vulcan.
<v Speaker 3>Astronomers spent decades looking for it during eclipses. They never
<v Speaker 3>found it because it didn't exist.
<v Speaker 2>The problem wasn't a missing planet, The problem was the math.
<v Speaker 2>The physics itself was incomplete.
<v Speaker 3>Then comes Einstein in nineteen fifteen. He applies his new
<v Speaker 3>general theory of relativity to the problem. He calculates how
<v Speaker 3>the Sun's mass warps space time and what did he find?
<v Speaker 3>And the numbers matched perfectly. That extra wobble was exactly
<v Speaker 3>what relativity predicted. It was the first solid proof that
<v Speaker 3>Einstein was right and made him a celebrity overnight.
<v Speaker 2>So relativity explained the wabble of mercury.
<v Speaker 3>Yes, but here is the irony. In our solar system,
<v Speaker 3>that relativistic wobble is tiny. It's a curiosity, and strangely enough,
<v Speaker 3>computer simulation suggests that in our case, relativity actually stabilizes
<v Speaker 3>the Solar system.
<v Speaker 2>Wait, really, how does it stabilize it?
<v Speaker 3>Yes, Without those subtle relativistic corrections over billions of years,
<v Speaker 3>the gravitational interactions between the planets could have led to
<v Speaker 3>chaotic diffusion. Mercury might have been destabilized. Einstein might have
<v Speaker 3>actually saved mercury from being flung into the Sun.
<v Speaker 2>That is wild. So in our system, Einstein is the
<v Speaker 2>protector keeps mercury in line. He's the celestial bodyguard.
<v Speaker 3>But in these binary systems, that same force, that same
<v Speaker 3>equation comes the destroyer because the warping is so much
<v Speaker 3>more intense. With two stars, the effect flips from a
<v Speaker 3>stabilizer to a destabilizer.
<v Speaker 2>Tum I had a great line about this in the report.
<v Speaker 2>General relativity is stabilizing systems in some ways and disturbing
<v Speaker 2>them in other ways. It's not good or bad. It's
<v Speaker 2>just gravity.
<v Speaker 3>It shows the universality of the theory. The same math
<v Speaker 3>that keeps our fet on the ground and guides our
<v Speaker 3>GPS satellites is the same math that is flinging planets
<v Speaker 3>into the void in the alpha centaur neighborhood.
<v Speaker 2>So where does this research go next? Now that they've
<v Speaker 2>cracked the code on binary stars, where do they take
<v Speaker 2>this model?
<v Speaker 3>They are going bigger and more extreme. The researchers are
<v Speaker 3>looking at applying this to supermassive black holes.
<v Speaker 2>Oh wow, Okay, scale that up for me.
<v Speaker 3>Imagine two super massive black holes orbiting each other at
<v Speaker 3>the center of a galaxy. They likely have clusters of
<v Speaker 3>stars orbiting them.
<v Speaker 2>Like planet's orbiting stars, but its stars orbiting black holes.
<v Speaker 2>That's a mind bending image.
<v Speaker 3>Exactly, and the math should be the same. The same
<v Speaker 3>relative savistic resonance might be sweeping those stars away.
<v Speaker 2>So instead of a planet getting kicked out, you might
<v Speaker 2>have entire suns getting flung out of a galactic.
<v Speaker 3>Core, exactly high velocity stars ejected into intergalactic space. And
<v Speaker 3>they're also looking at binary pulsars, dead neutron stars spinning wildly.
<v Speaker 3>The physics holds up.
<v Speaker 2>It just shows that even though general relativity is over
<v Speaker 2>one hundred years old, we are still finding new ways
<v Speaker 2>to apply it. We're still discovering that it controls the
<v Speaker 2>architecture of the universe in ways we didn't expect.
<v Speaker 3>It is the gift that keeps on giving. It turns
<v Speaker 3>out that simple orbital mechanics aren't simple at all.
<v Speaker 2>So let's bring this all home. What does this mean
<v Speaker 2>for us? For the person listening who just wanted to
<v Speaker 2>know about tattooing.
<v Speaker 3>I think it shifts our perspective. We started this discussion
<v Speaker 3>looking for a fantasy, a double sunset. It's a romantic image,
<v Speaker 3>and we found out that while the image is beautiful,
<v Speaker 3>the reality is violent.
<v Speaker 2>We found an empty desert, we.
<v Speaker 3>Did, but we learned why it's empty. We learned that
<v Speaker 3>the universe isn't just a static backdrop where things hang
<v Speaker 3>in place. It's a dynamic evolving machine. The stars change,
<v Speaker 3>their orbits shrink, space time warps.
<v Speaker 2>And the poor planets are caught in the middle.
<v Speaker 3>The planets are the victims of the stars evolution. It
<v Speaker 3>resolves the paradox we don't see the tattooings because the
<v Speaker 3>physics of their parents, the binary stars, eventually turns against them.
<v Speaker 2>It makes you wonder about the stability of our own footing,
<v Speaker 2>doesn't it. We tend to think of the Earth's orbit
<v Speaker 2>as this permanent, fixed track, like a train on rails.
<v Speaker 2>We assume we will be here forever.
<v Speaker 3>That is a comforting illusion. But this research reminds us
<v Speaker 3>that orbits are breathing things. Gravity isn't just a glue
<v Speaker 3>holding us together. It's a complex engine. It evolves over time.
<v Speaker 2>It really does. It leads me with this thought, we
<v Speaker 2>are incredibly lucky we have a single boring star. We
<v Speaker 2>have a nice, stable orbit, because if we lived in
<v Speaker 2>one of those exciting binary systems, the very physics that
<v Speaker 2>keeps our feet on the ground gravity I have long
<v Speaker 2>ago decided to fling our planet out into the cold dark.
<v Speaker 3>We should be thankful for our boring son.
<v Speaker 2>I am definitely thankful for the boring sun today. As
<v Speaker 2>am I, thanks for listening to this exploration of the cosmos.
<v Speaker 2>It's been a fascinating journey into the invisible forces that
<v Speaker 2>shape our galaxy.
<v Speaker 3>Indeed, keep looking up
<v Speaker 2>The characters