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, if you are listening to this right now, I
Speaker 2: want you to just imagine standing in the middle of
Speaker 2: the Pacific Ocean. Okay, and it is the pitch black of.
Speaker 3: Night sounds terrifying on it.
Speaker 2: Yeah, And you are holding just a standard every day flashlight,
Speaker 2: oh wow. Okay, and your task is to find a single,
Speaker 2: specific microscopic organism floating somewhere out there in the water,
Speaker 2: just by wildly waving that beam of light around in.
Speaker 3: The dark, which is pretty much impossible, exactly.
Speaker 2: But for a very long time, that is exactly what
Speaker 2: the search for life outside our Solar system is felt like.
Speaker 2: I mean, humanity has managed to confirm over six thousand
Speaker 2: exoplanets so far.
Speaker 3: Yeah, over six thousand. It's a massive number, it is, But.
Speaker 2: Until recently, trying to find realistic, actual candidates for biology
Speaker 2: among all those churning gas giants and freezing rocks. It's
Speaker 2: just been completely overwhelming. You are basically wandering the cosmos
Speaker 2: hoping to bump into an alien microbe.
Speaker 3: Right, It's a sheer numbers game.
Speaker 2: Yeah, But today our mission is to understand a monumental
Speaker 2: shift in this entire field, a completely groundbreaking development that
Speaker 2: basically takes the flashlight out of our hands, drains the ocean,
Speaker 2: and hands us a highly specific, mathematically rigorous VIP guest
Speaker 2: list for the universe.
Speaker 3: That's a great way to put it.
Speaker 2: Thank you. It's a meticulously curated catalog of exactly forty
Speaker 2: five potentially habitable rocky exoplanets. It was published in March
Speaker 2: twenty twenty six by a team at Cornell University.
Speaker 3: It's a fundamental paradigm shift. We really need to emphasize
Speaker 3: the phrase mass discovery versus extreme precision.
Speaker 2: Here, Okay, unpack that for us.
Speaker 3: Well, if you look back over the last twenty or
Speaker 3: thirty years of astronomy, the headline was always about adding
Speaker 3: another planet.
Speaker 2: To the tally, like we found fifty more today exactly.
Speaker 3: The sheer volume of discoveries was the story. But this milestone.
Speaker 3: It's about the complete opposite. It is entirely about filtering the.
Speaker 2: Noise, filtering out the junk.
Speaker 3: Right, the team at Cornell didn't just look at the
Speaker 3: sky and make optimistic guesses. They took an incredibly vast,
Speaker 3: almost incomprehensible data set from the European Space Agency's GUY emission.
Speaker 4: That's the Data Release three, right, yes, specifically Data Release three,
Speaker 4: and they combined it with the NASA Exo Planet Archive,
Speaker 4: And by doing that they applied such rigorous, unforgiving physical
Speaker 4: and chemical.
Speaker 3: Constraints that they managed to just throw out thousands.
Speaker 2: Of worlds, leaving only the absolute most promising target.
Speaker 3: Exactly the best targets for future life detection missions.
Speaker 2: I want to pause on that phrase filtering the noise,
Speaker 2: because if you aren't deeply entrenched in planet tis very science,
Speaker 2: it is really hard to overstate how chaotic that noise
Speaker 2: actually is.
Speaker 3: Oh, it's incredibly chaotic.
Speaker 2: Right, six thousand confirmed worlds isn't a list of six
Speaker 2: thousand earths. We are talking about gas giants the size
Speaker 2: of Jupiter, but they orbit so close to their star
Speaker 2: that they are just burning at thousands of degrees jupiters
Speaker 2: yet or we are talking about planets where it literally
Speaker 2: rains molten glass sideways because the winds are moving at
Speaker 2: supersonic speeds.
Speaker 3: It's a very violent universe.
Speaker 2: Just totally hostile environments. And out of all of that chaos,
Speaker 2: this team, led by Professor Lisa Koltenegger, whittled the entire
Speaker 2: known universe down to forty five specific.
Speaker 3: Names, forty five very special places.
Speaker 2: Forty five places where you could theoretically look for something
Speaker 2: looking back. But here's my immediate question, how do you
Speaker 2: confidently throw away nine hundred and fifty five planets.
Speaker 3: It's a brutal process, honestly, right.
Speaker 2: If we are sitting here on Earth making sweeping judgments
Speaker 2: about rocks billions of miles away, what is the actual
Speaker 2: mechanism for saying yes to one and no to five
Speaker 2: thousand others?
Speaker 3: Well, the very first sweep of that cosmic sieve is
Speaker 3: based entirely on density and radius. They instantly eliminate anything
Speaker 3: that isn't rocky.
Speaker 2: So gas giants are just out completely on.
Speaker 3: If a planet has a thick, crushing gaseous envelope like Jupiter, Saturn,
Speaker 3: or even Neptune, it is immediately off the list.
Speaker 2: Because we need a surface exactly.
Speaker 3: We are looking for a specific type of surface habitability,
Speaker 3: meaning a solid surface where liquid water could actually pool.
Speaker 3: But the real heavy lifting of this filtering process it
Speaker 3: comes from a concept called the empirical habitable zone.
Speaker 2: Okay, I have to jump in here, because whenever the
Speaker 2: phrase habitable zone or goldilock zone gets tossed around, it
Speaker 2: always sounds so, I don't know, aggressively cozy.
Speaker 3: Right, like a nice galactic suburb.
Speaker 2: Exactly, not too hot, not too cold, just right. But
Speaker 2: the word empirical implies we are basing this on hard evidence, right,
Speaker 2: So what is the actual hard evidence anchoring this zone?
Speaker 3: The evidence this is our own solar system. That is
Speaker 3: what makes it empirical.
Speaker 2: Oh I see yeah.
Speaker 3: Instead of just running purely theoretical thermodynamic models, we use
Speaker 3: our immediate planetary neighbors as the ultimate undeniable benchmark.
Speaker 2: So Earth is the baseline.
Speaker 3: Erse is obviously the perfect baseline. We know for a
Speaker 3: fact that liquid water and biology exist here. But to
Speaker 3: define the inner edge, the absolute too hot boundary, we
Speaker 3: look toward the sun to Venus.
Speaker 2: Because Venus is a nightmare.
Speaker 3: Precisely, Venus represents the extreme limit of a runaway greenhouse effect.
Speaker 3: And to define the outer edge the two cold boundary,
Speaker 3: we look outward to Mars.
Speaker 2: Which is essentially a frozen desert.
Speaker 3: Right, Mars represents a world with a severely thin atmosphere
Speaker 3: where water simply cannot exist in a stable liquid state
Speaker 3: on the surface for any meaningful geological timeframe.
Speaker 2: I'm going to push back heavily on the cozy aspect
Speaker 2: of this, then, because if we are using Venus and
Speaker 2: Mars as our benchmarks, well, both of those planets are
Speaker 2: technically in our son's general neighborhood.
Speaker 3: There are literal nextdoor neighbors. Right.
Speaker 2: Yet, if you were to stand on the surface of
Speaker 2: Venus right now, you would be simultaneously crushed by atmospheric
Speaker 2: pressure ninety times heavier than Earth's, and you would be
Speaker 2: boiled alive by temperatures hot enough to melt lead.
Speaker 3: It is not a pleasant place, not at all.
Speaker 2: And if you magically teleported to Mars, your blood would
Speaker 2: boil from the low pressure while you simultaneously froze to death,
Speaker 2: and you wouldn't be able to draw a single breath
Speaker 2: of oxygen.
Speaker 3: Which is a very grim picture, but very accurate.
Speaker 2: So if these two completely dead violently hostile worlds are
Speaker 2: the boundaries of this zone. The traditional concept of a
Speaker 2: habitable zone feels wildly generous. The margins for life must
Speaker 2: be incredibly, unforgivingly tight.
Speaker 3: You've hit on the exact reason why this catalog is
Speaker 3: such a towering achievement. The margins are razor thin, I
Speaker 3: can imagine, and frankly, the astronomical community has struggled with
Speaker 3: this exact problem for a long time. Historically, we might
Speaker 3: spot an exoplanet and say, well, it's roughly in the
Speaker 3: habitable zone, but our measurements were fuzzy.
Speaker 2: We were just guessing.
Speaker 3: Basically, we're making very educated approximations. But this is where
Speaker 3: the Guy emissions data Release three becomes the absolute lynchpin
Speaker 3: of this entire endeavor. How So, we cannot know if
Speaker 3: a planet is walking that impossible tightrope between becoming a
Speaker 3: Venus or a Mars unless we know exactly, and I
Speaker 3: mean down to the decimal point, how much energy is
Speaker 3: hitting its surface.
Speaker 2: And to know how much energy is hitting the planet,
Speaker 2: you have to know exactly what the star is doing exactly.
Speaker 2: But how does a satellite like Gaya actually figure that out?
Speaker 2: If we are looking at a star that is fifty
Speaker 2: light years away. It's just a blurry pixel of light.
Speaker 2: How do we move from a pixel to knowing the
Speaker 2: exact radiation environment of a planet orbiting it.
Speaker 3: It all comes down to solving the distance problem through
Speaker 3: something called astrometry.
Speaker 2: Okay, astrometry.
Speaker 3: Let me give you an example. Okay. Imagine you are
Speaker 3: holding your thumb out at arm's length.
Speaker 2: All right, I'm picturing it.
Speaker 3: If you close your left eye and then open it
Speaker 3: and close your right eye, your thumb appears to jump
Speaker 3: back and forth against the background of the wall.
Speaker 2: Right, Yeah, it shifts.
Speaker 3: That apparent shift is parallax. Guya does exactly that, but
Speaker 3: on a cosmic scale. It measures the precise position of
Speaker 3: a star in the sky. Then, six months later, when
Speaker 3: Earth and Gaya, which orbits out at the l to
Speaker 3: lagrange point, has moved halfway across the Solar System, it
Speaker 3: measures the star's position again.
Speaker 2: Oh wow.
Speaker 3: By measuring that incredibly tiny apparent shift against the distant
Speaker 3: background galaxies, Gaya calculates the exact geometric distance to that star.
Speaker 2: So it's literally just high school trigonometry just scaled up
Speaker 2: to billions of miles essentially.
Speaker 3: Yes, but the precision required is mind boggling. We are
Speaker 3: talking about measuring angles so small it's like trying to
Speaker 3: measure the width of the human hair from miles away.
Speaker 2: That is insane.
Speaker 3: It is. Now, why does distance matter so much? Because
Speaker 3: of the inverse square law of light.
Speaker 2: Meaning the further away something is the dimmer it look.
Speaker 3: Right, if you see a star in the sky, you
Speaker 3: know it's apparent brightness, how bright it looks to your telescope.
Speaker 3: But a star could look dim because it's a small,
Speaker 3: weak star right next door. Or it could look dim
Speaker 3: because it's an absolute monster of a star that is
Speaker 3: incredibly far away. Oh, I say, once Gaya gives you
Speaker 3: the exact distance, yeah, you can calculate its true intrinsic luminosity.
Speaker 3: You know exactly how much energy that star is actually
Speaker 3: pumping out into space.
Speaker 2: Which means the Cornell team finally have the missing variable.
Speaker 3: Yeah.
Speaker 2: Before Guya, they might have been guessing, uh, we think
Speaker 2: this planet gets enough light to be warm. But with
Speaker 2: Gaya's data they could say, we know for a mathematical
Speaker 2: fact that this specific planet receives exactly one three hundred
Speaker 2: and sixty watts per square meter or whatever.
Speaker 3: The exact number is correct. They calculate the exact stellar
Speaker 3: energy flux, and if that mathematical flux pushes the planet
Speaker 3: even a fraction of a percent towards the Venus extreme,
Speaker 3: they mercifully cut it from the list.
Speaker 2: Just totally ruthless.
Speaker 3: Very ruthless. If it drops toward the Mars extreme, it's out.
Speaker 3: They ran thousands of planets through this mathematical formula, and
Speaker 3: that is how they found the forty five that actually
Speaker 3: sit perfectly within that mathematical sweet spot.
Speaker 2: It really paints a picture of extreme planetary fragility, doesn't it.
Speaker 3: It really does.
Speaker 2: Imagine being a planet hunter looking at a distant star
Speaker 2: and realizing the planet orbiting it has to walk this
Speaker 2: absolute tightrope.
Speaker 3: A very precarious tightrope.
Speaker 2: A tiny fraction too much radiation, the oceans boil off
Speaker 2: into space, the hydrogen escapes, and you have venus A
Speaker 2: fraction too little, The carbon dioxide freezes out, the atmosphere collapses,
Speaker 2: and the whole world turns into a giant snowball.
Speaker 3: Which is why finding forty five planets that survived that
Speaker 3: math is staggering.
Speaker 2: It is, but as I understand it, the researchers didn't
Speaker 2: even stop there.
Speaker 3: Did they No, they did not.
Speaker 2: They looked at these forty five ideal candidates and decided
Speaker 2: the empirical habitable zone wasn't strict enough. They added an
Speaker 2: even more unforgiving filter.
Speaker 3: They did for the sake of maximum conservatism. They applied
Speaker 3: a three D habitable zone filter.
Speaker 2: Okay, what does that mean?
Speaker 3: Well, the initial empirical zone we just discussed is incredibly useful,
Speaker 3: but it fundamentally relies on generalized one dimensional assumptions.
Speaker 2: Like treating the planet as a flat circle.
Speaker 3: Basically, it treats the planet almost like a flat, uniform sphere,
Speaker 3: absorbing energy evenly. But reality is infinitely more complex. The
Speaker 3: three D filter accounts for atmospheric dynamics, planetary rotation, and
Speaker 3: how heat actually moves around a three dimensional globe.
Speaker 2: Wow.
Speaker 3: When they ran the forty five planets through this hyper
Speaker 3: strict three dimensional gauntlet, the list narrowed down even further
Speaker 3: to just twenty four ultra high priority worlds.
Speaker 2: Okay, so treating a planet like a flat sphere is
Speaker 2: like well, it's like looking at a static two D
Speaker 2: photo of a house and trying to guess if it's
Speaker 2: warm inside.
Speaker 3: That's a good analogy.
Speaker 2: You see the sun hitting the roof in the photo,
Speaker 2: and you guess, sure, it looks cozy. But the three
Speaker 2: D model is like actually walking through the house.
Speaker 3: Right.
Speaker 2: In the three D model, you aren't just looking at
Speaker 2: the sun. You are checking the insulation in the walls.
Speaker 2: You are kneeling down to feel for drafts under the door,
Speaker 2: you are seeing how the air conditioning ducts circulate the air,
Speaker 2: and you're checking the actual thermostat. Yes, a flat photo
Speaker 2: might show a house bathed in sunshine, but the three
Speaker 2: D walk through tells you if the living room is
Speaker 2: freezing because all the heat escapes through a drafty window.
Speaker 3: I like the house analogy, but I'm going to complicate
Speaker 3: it a bit. Please do, because planetary climate is far
Speaker 3: more chaotic than a drafty window. Imagine that house is
Speaker 3: also spinning at one thousand miles an hour.
Speaker 2: Okay, now I'm dizzy.
Speaker 3: And the heater isn't just a furnace in the basement,
Speaker 3: It's a massive nuclear reactor hanging in the sky, bombarding
Speaker 3: the house with radiation. Planets are dynamic, rotating fluid systems.
Speaker 3: They have varied topographies, massive oceans that act as heat sinks,
Speaker 3: and swirling atmosphere currents governed by the Coriolis effect.
Speaker 2: So how does a three D model actually simulate all
Speaker 2: of that? Because that sounds like an unbelievable amount of math.
Speaker 3: It requires General circulation models or GCMs.
Speaker 2: Are those like weather simulators Exactly.
Speaker 3: They are essentially the same supercomputer models we use to
Speaker 3: predict weather and climate change here on Earth. They chop
Speaker 3: the planet's atmosphere and oceans into a three dimensional grid
Speaker 3: millions of little boxes. Okay, then they calculate the thermodynamics,
Speaker 3: the fluid dynamics, and the radiative transfer, how light bounces
Speaker 3: around in every single box, and how each box interacts
Speaker 3: with its neighbors. What's fascinating here is that this is
Speaker 3: absolutely critical because of a phenomenon called tidal locking.
Speaker 2: Right tidal locking, I've heard of this. That's when a
Speaker 2: planet orbits so close to its star that the star's
Speaker 2: gravity basically grabs hold of the planet's uneven mass and
Speaker 2: forces it to stop spinning relative to the star. Yes,
Speaker 2: the rotation matches the orbit, so one side is always
Speaker 2: facing the sun in perpetual daylight and the other side
Speaker 2: is staring out into the blackness of space in perpetual
Speaker 2: freezing night.
Speaker 3: Exactly. Our Moon is tidally locked Earth, which is why
Speaker 3: we always see the same face. Oh right, now, if
Speaker 3: you have an exoplanet that is tidally locked to a
Speaker 3: red dwarf star, a simple one D or two D
Speaker 3: model might take the scorching heat of the day side,
Speaker 3: average it with the freezing cold of the night side,
Speaker 3: and spit out a number that says, hey, the average
Speaker 3: global temperature is sixty five degrees It's perfectly habitable.
Speaker 2: But no one actually experiences the average Precisely, half the
Speaker 2: planet is an absolute furnace and the other half is
Speaker 2: a solid ice block.
Speaker 3: Exactly. But a three D model asks the vital question,
Speaker 3: how does the atmosphere transport the scorching heat from the
Speaker 3: day side to the freezing night side?
Speaker 2: Oh, so the wind carries the heat.
Speaker 3: Does the heat rise at the substellar point the exact
Speaker 3: spot where the Sun is directly overhead, and flow high
Speaker 3: in the atmosphere to the night side, creating massive planet
Speaker 3: wide hurricane force winds.
Speaker 2: That sounds terrifying.
Speaker 3: It is does the ocean have currents that can distribute
Speaker 3: that thermal energy? If the atmosphere is too thin, it
Speaker 3: can't transport the heat, and the atmosphere on the dark
Speaker 3: side might literally freeze solid and collapse onto the ground
Speaker 3: a snow.
Speaker 2: Wait, the air itself freezes.
Speaker 3: Yes, atmosphere it collapse. Yeah, Well, if it's too thick,
Speaker 3: the heat transport might be so efficient that the whole
Speaker 3: planet just cooks. That global circulation of heat absolutely makes
Speaker 3: or breaks a planet's ability to hold onto liquid water.
Speaker 2: And that really makes you stop and wonder about the
Speaker 2: planet sitting right on the razor's edge of this three
Speaker 2: D boundary.
Speaker 3: It does.
Speaker 2: You could have a world that is, by all accounts,
Speaker 2: a lush, beautiful paradise. It has flowing water, thick clouds,
Speaker 2: stable temperatures. But because it's sitting right on the absolute
Speaker 2: extreme margin of that three D habitable zone, what happens
Speaker 2: if there's a slight orbital.
Speaker 3: Shift the tiny wabble, yeah.
Speaker 2: Or what if there's a minor atmosphere change, like a
Speaker 2: slight natural increase in a greenhouse gas from a volcano.
Speaker 2: It feels like it wouldn't take much to tip one
Speaker 2: of these paradise worlds completely over the edge.
Speaker 3: It really wouldn't.
Speaker 2: It could trigger a positive feedback loop where the water
Speaker 2: starts evaporating. Water vapor acts as a greenhouse gas traps
Speaker 2: more heat, evaporates more water, and suddenly your paradise is
Speaker 2: just a barren Venus like wasteland, which.
Speaker 3: Tells us a very sobering truth about the universe. Habitability
Speaker 3: isn't necessarily a permanent state.
Speaker 2: It's temporary.
Speaker 3: It can be a highly temporary, fleeting phase in a
Speaker 3: planet's long geological evolution. We know Mars was likely habitable
Speaker 3: billions of years ago.
Speaker 2: It had rivers and stuff.
Speaker 3: It had river deltas and lakes, but it lost its
Speaker 3: magnetic field, the solar wind stripped its atmosphere, and it died.
Speaker 3: Venus may have had oceans, but the sun grew brighter
Speaker 3: over billions of years and it boiled away.
Speaker 2: Wow.
Speaker 3: Establishing this three D boundary is a massive leap forward
Speaker 3: because it strips away the overly optimistic candidates. It leaves
Speaker 3: us with twenty four worlds that have the most robust,
Speaker 3: resilient potential for maintaining stable, life supporting climates despite the
Speaker 3: chaotic nature of stellar evolution.
Speaker 2: So, with the list completely whittled down to the forty
Speaker 2: five overall candidates and the twenty four absolute ultra high
Speaker 2: priority world, I want to talk about the actual names
Speaker 2: on this cosmic VIP list, let's do it. Who are
Speaker 2: the neighbors we might actually be visiting or at least
Speaker 2: staring at very intensely, because if you are listening to
Speaker 2: this and you follow astronomy at all, some of these
Speaker 2: names are going to jump out at you.
Speaker 3: Definitely.
Speaker 2: You have Proxima Sentry B, which is incredibly exciting because
Speaker 2: it's our absolute closest stellar neighbor. It's literally the star
Speaker 2: next door, and it has a rocky world in.
Speaker 3: The zone, a fascinating target.
Speaker 2: You've got several members of the famous Trappist one system.
Speaker 2: There's Kepler one to eighty six, which was a huge
Speaker 2: deal when it was discovered because it was the first
Speaker 2: Earth sized planet found in a habitable zone.
Speaker 3: That was a historic fine.
Speaker 2: And there's LHS eleven forty B. But beyond the planets themselves,
Speaker 2: I find the team behind this catalog just absolutely fascinating.
Speaker 3: Great group.
Speaker 2: You have Professor Koltenegger who directs the Carl Sagan Institute
Speaker 2: at Cornell, but she co authored this massive paradigm shifting
Speaker 2: catalog with an undergraduate student, Abigail Bowl and recent alumni
Speaker 2: Lucas Lawrence and Gillis Lowry. Yes, we're literally talking about
Speaker 2: college students and recent grads who are fundamentally riding the
Speaker 2: road map for the future of humanity's space exploration.
Speaker 3: It's a wonderful aspect of modern astronomy. It speaks volumes
Speaker 3: about the accessibility and the sheer quality of the data.
Speaker 2: We now have, meaning anyone can look at it.
Speaker 3: Essentially. Yes, decades ago, obtaining this kind of data required
Speaker 3: a lifetime of lobbying for telescope time. Now massive surveys
Speaker 3: like GAYA and the NASA Exoplanet Archive are democratized.
Speaker 2: That's incredible.
Speaker 3: They allow a dedicated team combining seasoned expertise with brilliant,
Speaker 3: highly motivated young minds to synthesize decades of observations into
Speaker 3: a precise, actionable database. And it's important to note that
Speaker 3: they did just list these planets arbitrarily. They purposefully categorize
Speaker 3: them to test very specific boundaries of planetary physics.
Speaker 2: Right, because if you just wanted forty five Earth clones,
Speaker 2: you might miss out on understanding how life works an
Speaker 2: extreme environment exactly.
Speaker 3: For instance, some planets on the list have irradiation environments
Speaker 3: that are practically identical to modern Earth. They are the
Speaker 3: safe bets the easy ones, but others sit right on
Speaker 3: the very edges of the habitable zone specifically chosen so
Speaker 3: we can test where exactly those boundaries fail. If we
Speaker 3: look at a planet on the inner edge and see
Speaker 3: it hasn't turned into venus, our models need to adjust.
Speaker 2: Now here's where it gets really interesting for me. This
Speaker 2: is something I genuinely don't fully understand, but it sounds wild.
Speaker 2: The catalog specifically includes planets with highly eccentric orbits. Ah So,
Speaker 2: instead of a nice, neat relatively circular path around their
Speaker 2: star like Earth has, their orbits are stretched out into.
Speaker 3: Long ovals, highly elliptical.
Speaker 2: They are swinging in violently close to the star and
Speaker 2: then getting flung far out into the freezing depths of
Speaker 2: their solar system. What on Earth, or rather what out there,
Speaker 2: would the climate dynamics actually look like on.
Speaker 3: A planet like that? It would be extreme, to say
Speaker 3: the least.
Speaker 2: If I'm standing on a rocky world with a highly
Speaker 2: eccentric orbit, am I just experiencing extreme whiplash inducing seasons
Speaker 2: like a summer where the oceans are practically steaming, followed
Speaker 2: a few months later by a winter where the entire
Speaker 2: atmosphere is freezing onto the ground as solid ice.
Speaker 3: Orbital mechanics dictate that you absolutely would experience those extremes.
Speaker 3: According to Kepler's laws of planetary motion, a planet moves
Speaker 3: fastest when it is closest to its star. That's periapsis, right, yes,
Speaker 3: at periapsis, and it moves slowest when it is farthest away,
Speaker 3: at apoapsis. So let's play out the scenario you just described.
Speaker 3: As the planet swings deeply into the inner Solar System,
Speaker 3: the sudden, violent spike in stellar irradiation could trigger massive,
Speaker 3: rapid evaporation of surface water. Oh wow, The latent heat
Speaker 3: of vaporization would pump enormous amounts of energy into the atmosphere,
Speaker 3: creating incredibly dense, chaotic planet wide storm systems hurricanes that
Speaker 3: dwarf anything on Earth.
Speaker 2: And because it's moving fastest at that close point, that
Speaker 2: hellish summer might actually be quite sure exactly.
Speaker 3: It whips around the star and then begins the long,
Speaker 3: slow climb back out in the deep space.
Speaker 2: And then it gets cold cold.
Speaker 3: As it swings back out to the farthest reaches of
Speaker 3: its orbit, the solar radiation drops off a cliff. All
Speaker 3: that water vapor that got pumped into the atmosphere, it
Speaker 3: would begin to condense and eventually precipitate out as global rain,
Speaker 3: then snow, and perhaps even solid sheets of ice covering
Speaker 3: the oceans.
Speaker 2: That sounds completely inhospitable. Why on Earth would the Cornell
Speaker 2: team put a planet like that on a VIP list
Speaker 2: for life?
Speaker 3: Because studying these weird oh's, as we might call them,
Speaker 3: is vital for understanding the absolute limits of biology. What
Speaker 3: do you mean, Well, life on Earth is remarkably adaptable.
Speaker 3: We find extremophiles in the boiling acidic hydro thermal vents
Speaker 3: at the bottom of the ocean, and we find them
Speaker 3: locked in the ice of Antarctica.
Speaker 2: True life finds a way.
Speaker 3: If a planet has a deep ocean, the sheer thermal
Speaker 3: mass of that water might buffer the extreme temperature swings.
Speaker 3: The surface might freeze, but deep down the water remains
Speaker 3: liquid and stable.
Speaker 2: So the aliens are just hiding under the ice during winter.
Speaker 3: Essentially, yes, if we find biological cigus nature is on
Speaker 3: a planet with whiplash seasons, it completely broadens our understanding
Speaker 3: of the extreme conditions under which life can persist. It
Speaker 3: forces us to abandon our earth centric biases.
Speaker 2: That makes a lot of sense. It's about testing the
Speaker 2: extremes and speaking of testing boundaries, the researchers also specifically
Speaker 2: highlighted some of the oldest known habitable zone rocky.
Speaker 3: Planets on the list, yes, the ancient ones.
Speaker 2: Which if you think about it from an evolutionary perspective,
Speaker 2: makes perfect sense. Time is arguably the most important factor
Speaker 2: in the universe.
Speaker 3: It is the most crucial ingredient for complexity. If we
Speaker 3: connect this to the bigger picture of evolutionary biology, we
Speaker 3: have to look at our own history. We know that
Speaker 3: on Earth life didn't just appear fully formed overnight. Right
Speaker 3: The Earth is roughly four and a half billion years old.
Speaker 3: For the first billion years, it was a hellscape of
Speaker 3: magma and asteroid bombardments. Once it cooled, simple single celled
Speaker 3: organisms emerged, but they stayed simple for billions.
Speaker 2: Of years, just floating blobs.
Speaker 3: It took an unam measurably long time for cells to
Speaker 3: develop nuclei, to form multicellular life, and eventually to trigger
Speaker 3: the Cambrian Explosion where complex animals emerged.
Speaker 2: So if a planet is relatively young, say just a
Speaker 2: billion years old, even if it has water and perfect temperatures,
Speaker 2: we might just be looking at a global ocean full
Speaker 2: of invisible slime.
Speaker 3: Correct slime is life, and finding it would be the
Speaker 3: greatest discovery in human history, but it's not complex life.
Speaker 3: By actively identifying these ancient, rocky world's planets that age
Speaker 3: estimates suggests are six, seven, or even eight billion years old,
Speaker 3: the catalog provides us with targets that offer the absolute
Speaker 3: longest available runway for biology to have taken hold.
Speaker 2: That is profound.
Speaker 3: If a planet has been sitting in a stable, habitable
Speaker 3: configuration for eight billion years without suffering a runaway greenhouse
Speaker 3: effect or losing its atmosphere, the complexity of the chemistry
Speaker 3: and potentially the biology could be staggering compared to a
Speaker 3: younger world. We are looking at environments that have had
Speaker 3: nearly double the evolutionary time of Earth.
Speaker 2: So we have this incredible VIP list. We have the
Speaker 2: oldest planets, the weirdest eccentric planets, the most earth like
Speaker 2: safe bets, and our literal nextdoor neighbors. The map is drawn,
Speaker 2: it is, But if I'm listening to this, my next
Speaker 2: logical question is what do we actually do with a
Speaker 2: list of forty five planets that are trillions of miles away.
Speaker 2: We have the names, we have the coordinates, but we
Speaker 2: can't exactly send a probe there, not right now, No yet.
Speaker 2: According to the researchers, this isn't just a fun theoretical streadsheet.
Speaker 2: This is a highly practical, literal roadmap for the most
Speaker 2: advanced technology humanity has ever built or will build in
Speaker 2: the next century.
Speaker 3: Professor Koldnikker actually summarize the utility of this catalog perfectly.
Speaker 3: She stated, our paper reveals where you should travel to
Speaker 3: find life if we ever build a project Hail Mary's Spacecraft.
Speaker 2: Oh, I love that book.
Speaker 3: It's a great reference. Now, obviously that is a reference
Speaker 3: to science fiction. We do not currently possess interstellar spacecraft
Speaker 3: capable of traveling at fractions of the speed of light
Speaker 3: to proximusentry the Trappist one system. Setting a physical object
Speaker 3: there is for now impossible.
Speaker 2: So what's the practical use today?
Speaker 3: The practical reality is that this catalog optimizes observing time
Speaker 3: for our current and future technological marvels. We are talking
Speaker 3: about humanity's greatest eyes in the sky, and.
Speaker 2: When we say eyes in the sky, we are talking
Speaker 2: about machines that cost billions of dollars and take decades
Speaker 2: to build. We're talking about the James Webb Space Telescope
Speaker 2: or JWST, which is operational right now. Yes, we're talking
Speaker 2: about massive ground based projects currently under construction, like the
Speaker 2: extremely Large Telescope the ELT. And we're talking about proposed
Speaker 2: future missions like the Habitable World's Observatory the HWO and
Speaker 2: the large Interferometer for exoplanets known as Life.
Speaker 3: Exactly, and to understand why this catalog is so critical,
Speaker 3: you have to understand the brutal economics of astronomy. Telescope
Speaker 3: times is not something as scientists can just casually sign
Speaker 3: out like a library book. I can imagine it is
Speaker 3: arguably the most scarce and fiercely competitive scientific resource on
Speaker 3: the planet.
Speaker 2: I imagine every astronomer on Earth has a pet project
Speaker 2: they want to point JWST at they do.
Speaker 3: Astronomers from all over the world submit incredibly detailed proposals
Speaker 3: detailing exactly what they want to look at, why it matters,
Speaker 3: and exactly how many hours of telescope time it will take.
Speaker 3: The over subscription rate is.
Speaker 2: Massive, meaning everyone wants time and there's none left.
Speaker 3: Far more requests for time than there are hours in
Speaker 3: a year. The committees that allocate this time are ruthless.
Speaker 3: You simply cannot afford to point a ten billion dollar
Speaker 3: machine at a random patch of sky and just hope
Speaker 3: something interesting happens. You need absolute mathematical certainty that the
Speaker 3: patch of sky you are scaring at holds the highest
Speaker 3: possible probability of yielding a significant scientific return.
Speaker 2: So this Cornell catalog acts as the ultimate filter. Yes,
Speaker 2: it's the ultimate trump card in a proposal. You don't
Speaker 2: have to say I think this planet might be habitable.
Speaker 2: You can say this planet has survived the empirical habitable
Speaker 2: zone filter, the thread climate model filter, and it is
Speaker 2: officially one of the twenty four best candidates in the
Speaker 2: known universe.
Speaker 3: It tells these incredibly expensive machines exactly where to look.
Speaker 3: It equips observers with clear, heavily vented priorities, and depending
Speaker 3: on the telescope, they will use incredibly complex techniques like
Speaker 3: what future telescopes might use direct imaging, where they literally
Speaker 3: try to block out the light of the host star
Speaker 3: with a protograph to see the faint glimmer of the
Speaker 3: planet itself. Others might use light curve analysis, but most
Speaker 3: importantly for our current capabilities with JWST. The catalog provides
Speaker 3: the perfect targets for a technique called transmission spectroscopy.
Speaker 2: I am so glad you brought up transmission spectroscopy because
Speaker 2: we don't have to wait thirty years for futuristic telescopes
Speaker 2: to see this in action. The James Web Space Telescope
Speaker 2: is up there right now, parked a million miles from Earth,
Speaker 2: staring down one of the most famous systems on this
Speaker 2: newly minted VIP list, the Trappist one system.
Speaker 3: It is actively gathering data as we speak.
Speaker 2: But to really appreciate what JAST is finding, we have
Speaker 2: to unpack how it's actually looking at them. Because it's
Speaker 2: not taking a photograph, is it. It's not zooming in
Speaker 2: with a super high resolution lens until it sees continents
Speaker 2: and oceans.
Speaker 3: No, taking a direct photograph of a rocky exoplanet with
Speaker 3: current technology is virtually impossible. The host star is simply
Speaker 3: too blindingly bright. It completely washes out the tiny, faint
Speaker 3: reflection of the planet.
Speaker 2: It's like trying to see a firefly next to a
Speaker 2: searchlight exactly.
Speaker 3: Instead, JWST is probing the atmospheres of these distant exoplanets
Speaker 3: using transmission spectroscopy during transits.
Speaker 2: Okay, let's break that down mechanically. What is a transit?
Speaker 3: The mechanics of a transit are relatively straightforward. From our
Speaker 3: specific vantage point here in the Solar System, the orbital
Speaker 3: plane of the exoplanet happens to be perfectly aligned edge
Speaker 3: on with.
Speaker 2: Us, so we're looking at it from the side.
Speaker 3: Yes, this means that as the planet orbits its star,
Speaker 3: we can watch as it passes directly in front of
Speaker 3: the stellar disc. When that happens, the solid rocky body
Speaker 3: of the planet blocks a tiny fraction of the starlight,
Speaker 3: causing a slight dip in the stars overall brightness, and.
Speaker 2: That dip is how we know the planet is there.
Speaker 3: Right, But the magic of transmission spectroscopy happens at the
Speaker 3: very edges of the planet.
Speaker 2: Because the entire planet isn't just solid rock. If it
Speaker 2: has an atmosphere, there is a tiny, incredibly thin halo
Speaker 2: of gas surrounding the rock.
Speaker 3: Exactly when the planet passes in front of the star,
Speaker 3: a minute fraction of the starlight doesn't hit the solid rock. Instead,
Speaker 3: it grazes the edge of the planet and filters through
Speaker 3: that incredibly thin sliver of atmospheric gas on its way
Speaker 3: to JWST's mirrors.
Speaker 2: I always try to visualize this because the scales are
Speaker 2: so insane. I think the easiest way to imagine transmission
Speaker 2: spectroscopy is to picture yourself trying to guess what color
Speaker 2: sunglasses someone is wearing.
Speaker 3: Okay, let's hear it.
Speaker 2: But this person is standing five miles away. Obviously, you
Speaker 2: can't just look and see the lenses from five miles away.
Speaker 2: They're way too small.
Speaker 3: Right.
Speaker 2: If you have that person stand directly in front of
Speaker 2: an incredibly bright and tense search light, and that searchlight
Speaker 2: shines directly through the lenses of their sunglasses and right
Speaker 2: into your eyes, the beam of light hitting your eyes
Speaker 2: is going to be altered. Ah. Yes, If the light
Speaker 2: suddenly looks tinted green, you know for a fact they
Speaker 2: are wearing green lenses. The material of the lenses absorbs
Speaker 2: certain colors of the light spectrum and let other colors
Speaker 2: pass through.
Speaker 3: Your analogy captures the basic mechanism beautifully, But let's make
Speaker 3: it more scientifically accurate. Because JWST's job is exponentially harder
Speaker 3: than that I figured as much. Imagine that search light
Speaker 3: is constantly fluctuating in brightness. You only get to look
Speaker 3: at the thung glasses for a few hours every couple
Speaker 3: of weeks, and the lenses are microscopic.
Speaker 2: Yikes.
Speaker 3: Okay, when starlight passes through the exoplanet's atmosphere, it isn't
Speaker 3: just being tinted a single color. The specific molecules floating
Speaker 3: in that gas, whether it's water, vapor, carbon dioxide, methane,
Speaker 3: or ozone, interact with the light photons on a quantum level.
Speaker 2: Wait, on a quantum level, how does a photon of
Speaker 2: light interact with a molecule of water.
Speaker 3: When a photon of light carrying a very specific amount
Speaker 3: of energy hits a molecule, it can cause the chemical
Speaker 3: bonds of that molecule to vibrate or rotate. But a
Speaker 3: water molecule will only absorb a photon if the photon
Speaker 3: has the exact specific wavelength that matches the water molecule's
Speaker 3: vibrational frequency. It's like a tuning fork.
Speaker 2: Oh, that makes sense.
Speaker 3: If it absorbs that photon, that specific wavelength of light
Speaker 3: goes missing from the beam. So when the rest of
Speaker 3: the starlight eventually reaches JWST's spectrograph, it gets split up
Speaker 3: into a rainbow like a prism.
Speaker 2: And there are chunks missing.
Speaker 3: Yes, scientists look at that rainbow and they see dark
Speaker 3: vertical bands where light is missing. Those dark bands are
Speaker 3: a chemical fingerprint. If they see a dark band at
Speaker 3: a specific wavelength, they can say a water molecule absorbed
Speaker 3: that light. Therefore there is water in that atmosphere.
Speaker 2: That is just phenomenal. We are literally reading the shadows
Speaker 2: of molecules cast across trillions of miles of space. And
Speaker 2: JWST is specifically built for this, isn't it. It doesn't
Speaker 2: look at visible light like our eyes do. It looks
Speaker 2: at infrared light.
Speaker 3: Yes, JWST is equipped with massive, incredibly sensitive infrared sensors.
Speaker 3: Infrared is the absolute perfect spectrum for finding these specific
Speaker 3: chemical signatures.
Speaker 2: Why infrared.
Speaker 3: The molecular bonds of biologically interesting compounds, things like water, methane,
Speaker 3: and carbon dioxide vibrate and absorb light very strongly at
Speaker 3: infrared wavelengths. The absorption bands in the infrared are deep
Speaker 3: and clear, making them much easier to detect than invisible light.
Speaker 2: And this brings us back to why the Trappist one
Speaker 2: system is the ultimate testing ground for this technology. Because
Speaker 2: earlier we mentioned how telescope time is fiercely competitive. If
Speaker 2: you want to catch a transit, you have to wait
Speaker 2: for the planet to actually cross in front of the star.
Speaker 2: If you are looking at Earth from another star system,
Speaker 2: you only get one transit a year. You'd have to
Speaker 2: stare at our Sun for a decade to get enough data.
Speaker 3: Which nobody has time for, right if this.
Speaker 2: One is different. It's an incredibly compact group of seven
Speaker 2: Earth sized worlds, all orbiting a cool red dwarf star
Speaker 2: just forty light years away. Forty light years is practically
Speaker 2: down the street in cosmic terms.
Speaker 3: It is remarkably close, which gives us an excellent signal
Speaker 3: to noise ratio. But the most crucial factor is that
Speaker 3: Trappis one is an m dwarf star, a red dwarf,
Speaker 3: meaning it's small. It is vastly smaller and cooler than
Speaker 3: our Sun. Because the star is so cool, its habitable
Speaker 3: zone is pulled in very, very close the planet's orbit tightly.
Speaker 3: Trappis one, for instance, completes an entire orbit a full
Speaker 3: year in just about six earth days.
Speaker 2: Six days. That means it transits in front of the
Speaker 2: star once a.
Speaker 3: Week, exactly Frequent transits mean frequent opportunities for JWST to
Speaker 3: catch that starlight filtering through the atmosphere. Scientists can't just
Speaker 3: look at one transit and get a perfect picture. The
Speaker 3: signal is too incredibly.
Speaker 2: Faint, so they have to add them up.
Speaker 3: Yes, they have to stack the data. They record dozens
Speaker 3: of transits over months and years, overlaying the data on
Speaker 3: top of each other to amplify the true atmospheric signal
Speaker 3: and cancel out the random noise. The tight orbits of
Speaker 3: red dwarf systems make this stacking process feasible within a
Speaker 3: human timeframe.
Speaker 2: Which means we actually have real data. We aren't just
Speaker 2: talking in theories anymore.
Speaker 3: No, the data has been pouring in.
Speaker 2: JAWST has been staring intently at one specific incredibly promising
Speaker 2: candidate in the system, Trappist one, and the data from
Speaker 2: the observations taken between twenty twenty three and twenty twenty
Speaker 2: five has been analyzed and the results are completely upending
Speaker 2: what scientists thought they would find. They're forcing a total
Speaker 2: rethink of atmospheric models.
Speaker 3: They really are. The recent observations of Trappis one are
Speaker 3: a masterclass in science progressing by the process.
Speaker 2: Of elimination, process of elimination.
Speaker 3: OK, when you have a rocky world the size of Earth,
Speaker 3: there are several hypothetical types of atmospheres it could hold.
Speaker 3: The JST data analyzes have largely ruled out the most
Speaker 3: extreme scenarios by looking for those deep absorption bands and
Speaker 3: crucially by not finding them.
Speaker 2: Let's walk through what they crossed off the list, because
Speaker 2: if I remember correctly, there are a lot of fears
Speaker 2: that all these red dwarf planets would just be baked
Speaker 2: dead husks.
Speaker 3: The first major scenario they ruled out was a thick
Speaker 3: carbon dioxide dominated atmosphere. The spectral signature is completely disfavor it.
Speaker 3: This is a massive relief because it means Trappist one
Speaker 3: is not a Venus like world suffering from a runaway
Speaker 3: greenhouse effect. If it added a thick CO two atmosphere,
Speaker 3: JWST would have seen massive, unmistakable absorption bands at specific
Speaker 3: infrared wavelengths.
Speaker 2: They weren't there, So we can confidently scratch Venus off
Speaker 2: the list of possibilities for Trappist one. That's a huge win.
Speaker 3: It is a huge win. But the data also doesn't
Speaker 3: match the signature of a thin, completely CO two heavy
Speaker 3: atmosphere either, like Mars. Right, it doesn't have the spectral
Speaker 3: footprint of Mars. Furthermore, the data has excluded the possibility
Speaker 3: of a puffy hydrogen rich primordial atmosphere.
Speaker 2: Wait, a puffy hydrogen atmosphere, what does that even look
Speaker 2: like physically? A rocky planet with hydrogen gas.
Speaker 3: Well, when planets form out of the potoplanetary disk of
Speaker 3: gas and dust surrounding a young star, they can sometimes
Speaker 3: sweek up and retain massive envelopes of hydrogen and helium gas.
Speaker 3: This is a primordial atmosphere.
Speaker 2: Okay.
Speaker 3: If a small rocky planet holds onto that hydrogen, it
Speaker 3: ends up looking somewhat like a miniature gas giant, a
Speaker 3: Meani Neptune.
Speaker 2: Oh.
Speaker 3: Interesting, The hydrogen envelope is very light, so it puffs
Speaker 3: out far into space. A puffy atmosphere creates a very large,
Speaker 3: easy to see transit signal. But the incredibly flat spectral
Speaker 3: lines for trapis one m tell us unequivocally that this
Speaker 3: thick hydrogen rich scenario is off the table.
Speaker 2: So if I am a planetary scientist looking at this
Speaker 2: JATABST data and I realize the atmosphere isn't a crushing
Speaker 2: hot venus, it isn't a freezing thin Mars, and it
Speaker 2: isn't a puffy, gaseous hydrogen ball. What exactly is left
Speaker 2: if we've eliminated all the extremes, what is tropis ONEm
Speaker 2: actually made of?
Speaker 3: By ruling out those extremes, the data leaves open two
Speaker 3: incredibly thrilling possibilities. We must be intellectually honest and state
Speaker 3: the first possibility. The planet might simply be a bare,
Speaker 3: lifeless rock in space, completely stripped of any atmosphere whatsoever
Speaker 3: by the intense radiation of its star.
Speaker 2: A dead rock. Thrilling for a geologist maybe, but not
Speaker 2: for someone looking for life. But what is the second possibility?
Speaker 3: The second possibility is what keeps astronomers awake at night.
Speaker 3: Trapis one am could possess a thinner secondary atmosphere.
Speaker 2: A secondary atmosphere.
Speaker 3: This means an atmosphere that wasn't gathered from the stellar
Speaker 3: nebula during formation, but was generated later by the planet itself,
Speaker 3: likely through massive geological processes like volcanic outgassing, or brought
Speaker 3: in by comet impacts.
Speaker 2: Like it made its own air exactly.
Speaker 3: This secondary atmosphere wouldn't be dominated by primordial hydrogen or
Speaker 3: overwhelming carbon dioxide. Instead, it could be nitrogen rich, perhaps
Speaker 3: with traces of water, vapor, oxygen, or methane.
Speaker 2: A nitrogen rich secondary atmosphere that basically describes Earth exactly.
Speaker 3: Earth's atmosphere is roughly seventy eight percent nitrogen. Saturn's moon Titan,
Speaker 3: also has a thick nitrogen rich secondary atmosphere. If Trappist
Speaker 3: one m has an atmospheer akin to Earth or Titan,
Speaker 3: it drastically elevates its status as a primary candidate for astrobiology.
Speaker 2: It is just a staggering thought, a rocky planet forty
Speaker 2: light years away potentially wrapped in a blanket of nitrogen
Speaker 2: and methane orbiting a red sun. I know we are
Speaker 2: focusing heavily on this one specific planet, but I have
Speaker 2: to assume that what we learn from Trappis ONEm applies
Speaker 2: to the rest of the universe.
Speaker 4: Right.
Speaker 3: The importance of this stretches far, far beyond just Trappist One.
Speaker 3: By eliminating these specific extreme scenarios, the Venus, Mars and
Speaker 3: puffy hydrogen models, we are radically refining our foundational models
Speaker 3: for atmospheric evolution across the cosmos.
Speaker 2: Oh, because there's so many of these.
Speaker 3: Red dwarfs specifically, yes, for planets orbiting M dwarf stars
Speaker 3: or red dwarfs. And this is critical because red dwarfs
Speaker 3: are by a vast margin, the most common type of
Speaker 3: star in our entire galaxy. Upwards of seventy percent of
Speaker 3: all stars are red dwarfs seventy percent. If we want
Speaker 3: to understand the capitability, we have to understand what happens
Speaker 3: to rocky planets orbiting these specific stars. Gawst's work on
Speaker 3: trappis one m is literally writing the textbook on what
Speaker 3: kinds of atmospheres are physically and chemically plausible in the
Speaker 3: absolute most common planetary environments in the universe.
Speaker 2: But as with all great scientific endeavors, there is a massive,
Speaker 2: frustrating cosmic wildcard that threatens to muddy all of this pristine,
Speaker 2: beautiful data.
Speaker 3: There's always a catch.
Speaker 2: And ironically enough, the problem comes directly from the very
Speaker 2: star that provides the light we need to see the
Speaker 2: planets in the first place. The red dwarf itself isn't
Speaker 2: just sitting there being a passive flashlight. It's actively fighting us.
Speaker 3: Yes, this is known as the red dwarf dilemma. Researchers
Speaker 3: continually urge extreme caution when interpreting any spectral data from
Speaker 3: planets like traptist one M because of severe stellar activity,
Speaker 3: they're unstable. Red dwarfs are notoriously volatile. They are not calm,
Speaker 3: steady burning spheres of plasma like our Sun. They are
Speaker 3: fully convective stars, meaning the boiling place asma from their
Speaker 3: core churns all the way to the surface. This creates intense,
Speaker 3: chaotic magnetic fields.
Speaker 2: Hows they flare a lot.
Speaker 3: They are prone to incredibly violent stellar flares, massive eruptions
Speaker 3: of radiation that can bay their close orbiting planets in
Speaker 3: X rays and ultraviolet light, which.
Speaker 2: Sounds terrible for life on the surface obviously, But how
Speaker 2: does a flare mess up er data? If JWST is
Speaker 2: looking for the shadow of water molecules in the planet's atmosphere,
Speaker 2: how does the stars tantrum ruin.
Speaker 3: That It's not just the flares, it's the star spots.
Speaker 2: Star spots like sunspots.
Speaker 3: Much like sunspots on our Sun, Red dwarfs are frequently
Speaker 3: covered in massive star spots areas where the intense magnetic
Speaker 3: fields temporarily suppress the convection of heat, creating patches on
Speaker 3: the star's surface that are cooler and darker than the
Speaker 3: surrounding plasma. Okay, because they are cooler, the chemistry of
Speaker 3: the star in those spots actually changes. Molecules can temporarily
Speaker 3: form in the cooler regions of the star itself.
Speaker 2: Fait hold on, molecules can form on the star. I
Speaker 2: thought stars were too hot for molecules, that everything was
Speaker 2: just ripped apart into atoms and plasma.
Speaker 3: In a star like our sun. Yes, but red dwarfs
Speaker 3: are cool enough and their starspots are even cooler that
Speaker 3: simple molecules like water or titanium oxide can briefly form
Speaker 3: in the star's outer layers, and this creates a devastating
Speaker 3: problem for transmission spectroscopy.
Speaker 2: Let me guess. If water molecules are forming on the
Speaker 2: surface of the star, they're absorbing light before it even
Speaker 2: hits the planet.
Speaker 3: You've hit the nail on the head. This is stellar contamination.
Speaker 3: When the starlight passes through the planet's atmosphere, it carries
Speaker 3: the chemical signature of the star spot with it. Earlier
Speaker 3: in the decade, there were some hints or whispers in
Speaker 3: the data of methane and water on some exoplanets, which
Speaker 3: cause massive excitement, but later, rigorous studies came out suggesting
Speaker 3: that maybe that molecular signature wasn't coming from the planet's
Speaker 3: atmosphere at all.
Speaker 2: It was an illusion.
Speaker 3: It was an illusion. The water signature was coming from
Speaker 3: a massive, cool star spot rotating into view. Exactly is
Speaker 3: the planet transitd So.
Speaker 2: The star is essentially faking the data. It is projecting
Speaker 2: a hologram of water onto the planet. How do scientists
Speaker 2: even begin to solve that? If the signature for water
Speaker 2: looks exactly the same, whether it's from the star or
Speaker 2: the planet, how do you disentangle the two.
Speaker 3: That is the defining question the astronomical community is actively
Speaker 3: grappling with right now. How do we definitively separate the
Speaker 3: biological or chemical footprint of a planet from the magnetic
Speaker 3: temper tantrums of its host star.
Speaker 2: It sounds impossible.
Speaker 3: It requires incredibly sophisticated modeling of the star's magnetic activity.
Speaker 3: We have to map the star spots and subtract their
Speaker 3: spectrum from the planet spectrum. It requires continuous monitoring.
Speaker 2: So it's just really really hard mass.
Speaker 3: But we have to be honest. The current data sets,
Speaker 3: while absolutely revolutionary, are not quite sensitive enough to perfectly
Speaker 3: untangle the stellar contamination from the planetary signal. In every
Speaker 3: single case, the air bars are still too wide. We
Speaker 3: cannot yet give a definitive, undred percent certain answer on
Speaker 3: whether a world like Trappis one M has that sin
Speaker 3: gaseous envelope, or if it's just a bare rock reflecting
Speaker 3: a very noisy, spody star.
Speaker 2: It is such a cruel cosmic irony. The most common
Speaker 2: stars in the universe, the red dwarfs, are the ones
Speaker 2: statistically most likely to harbor these rocky planets in tight
Speaker 2: observable orbits. They offer the best targets, they offer the
Speaker 2: best chance to stack transit data. But they are also
Speaker 2: the exact stars that are most actively trying to blind
Speaker 2: our instruments and confuse our data with their chaotic magnetic fields.
Speaker 2: It's like trying to listen to a tiny, faint whisper
Speaker 2: from a planet, but its sun is constantly screaming into
Speaker 2: the microphone, and the sun happens to be whispering the
Speaker 2: exact same words you are trying to listen for.
Speaker 3: It's maddening.
Speaker 2: But even with these stellar tantrums, even with the extreme
Speaker 2: difficulty of separating the signal from the noise, the sheer
Speaker 2: combination of the Cornell Catalog in JWST's ongoing, relentless mission
Speaker 2: represents an absolute monumental leap forward. I feel like we
Speaker 2: are closer than ever to answering humanity's biggest, most existential question.
Speaker 3: We truly are. If you look at the arc of
Speaker 3: this entire endeavor, the field of exoplanet astronomy has fundamentally
Speaker 3: and irreversibly moved from an era of pure discovery we're
Speaker 3: simply counting the number of worlds and proving they existed
Speaker 3: was the primary goal, to an era of deep, rigorous characterization.
Speaker 2: We're not just counting anymore.
Speaker 3: No, we are no longer just asking is there a
Speaker 3: planet there? We know they are everywhere. We are now
Speaker 3: asking what is the detailed thermodynamic and chemical makeup of
Speaker 3: its atmosphere and what is its true mathematical potential for
Speaker 3: supporting biology?
Speaker 2: And the Cornell Catalog is the key.
Speaker 3: The Cornell Catalog, providing those forty five and the strictly
Speaker 3: modeled twenty four VIP candidates, provides the exact where to look.
Speaker 3: It acts as the ultimate filter for our most precious resources.
Speaker 2: And JWST provides the how.
Speaker 3: Yes, JWST with its incredibly powerful infrared transmission. Spectroscopy provides
Speaker 3: the how to look Future observatories. The the multi billion
Speaker 3: dollar massive machines currently being drafted and built will take
Speaker 3: this exact roadmap and build upon it. They won't be
Speaker 3: flying blind. They will be specifically scanning these prioritized candidates
Speaker 3: for genuine biosignatures.
Speaker 2: And when we say biosignatures, we aren't just looking for water.
Speaker 2: Water is everywhere. We're looking for things like unusual ratios
Speaker 2: of water, oxygen, and methane existing in the atmosphere at
Speaker 2: the same time, gases that actively react with each other
Speaker 2: and shouldn't exist together in large quantities for very long
Speaker 2: unless something like a massive biosphere of life is actively
Speaker 2: continuously producing them to replenish the atmosphere. And if you
Speaker 2: are listening to this, I really want you to take
Speaker 2: a second and think about the sheer scale of what
Speaker 2: we've walked through today. We aren't guessing anymore. We aren't
Speaker 2: throwing darts at a massive map of the Milky Way
Speaker 2: hoping to hit something interesting. Thanks to GAYA, thanks to
Speaker 2: extreme three D climate modeling, and thanks to relentless data analysis,
Speaker 2: we possess a prioritized mathematically rigorous list of forty five.
Speaker 2: I have actual physical places in the universe where the
Speaker 2: spark of life.
Speaker 3: Might have ignited the profound thought.
Speaker 2: Earth might be a total fluke, We might be a
Speaker 2: cosmic rarity and anomaly of geology and timing. Or Earth
Speaker 2: might just be one incredibly small part of a vibrant,
Speaker 2: bustling galactic community of living worlds. And for the very
Speaker 2: first time in all of human history, we aren't just
Speaker 2: philosophizing about it. We have the map, we have the list,
Speaker 2: and we have the tools to finally find out.
Speaker 3: The transition is complete. The search for life has moved
Speaker 3: out of the realm of science fiction and theoretical philosophy,
Speaker 3: and it has become a deeply structured, achievable, data driven
Speaker 3: scientific endeavor. It's happening right now, one transit, one photon,
Speaker 3: and one carefully selected planet at a time.
Speaker 2: And as we wrap up this discussion, I want to
Speaker 2: leave you with a final thought to really all over.
Speaker 2: We talked extensively about how the Cornell Catalog didn't just
Speaker 2: look for Earth clones. They specifically highlighted some of the
Speaker 2: oldest rocky planets in the habitable zone to act as
Speaker 2: extreme evolutionary test cases. I want you to think about time.
Speaker 3: Time is everything.
Speaker 2: Life on Earth took roughly four billion years to get
Speaker 2: from simple single cells floating in geothermal muk to complex
Speaker 2: creatures capable of building space telescopes, mapping the stars, and
Speaker 2: debating the nuances of red dwarf magnetic flares. Now imagine
Speaker 2: a rocky, ocean filled planet on this new VIP list,
Speaker 2: a planet that has been sitting in its star's perfect
Speaker 2: stable temperature zone, insulated by a thick atmosphere, not for
Speaker 2: four billion years, but for eight or.
Speaker 3: Nine billion years, double the time we've had.
Speaker 2: Exactly if the spark of life took hold in those
Speaker 2: alien oceans all those eons ago, with more than double
Speaker 2: the evolutionary runway that life on Earth had, what on Earth,
Speaker 2: or rather what out there, would it look like today