Habitable Worlds Observatory: Searching for Life Through Direct Exoplanet Imaging

<v Speaker 1>Welcome to Bedtime Astronomy. Explore the wonders of the cosmos
<v Speaker 1>with our soothing Bedtime Astronomie podcast. Each episode offers a
<v Speaker 1>gentle journey through the stars, planets, and beyond, perfect for
<v Speaker 1>unwinding after a long day. Let's travel through the mysteries
<v Speaker 1>of the universe as you drift off into a peaceful
<v Speaker 1>slumber under the night sky.
<v Speaker 2>You know the image, I mean, it's basically burned into
<v Speaker 2>our brains at this point, the pale blue dot.
<v Speaker 3>Oh yeah, Voyager one, Carl Sagan's whole speech. It's iconic.
<v Speaker 2>It is right, that one tiny pixel of light just
<v Speaker 2>hanging there in a sunbeam, and for what the last
<v Speaker 2>thirty plus years, that's been our shorthand for life in
<v Speaker 2>the universe. If you look for aliens, you look for
<v Speaker 2>the blue, you look for oceans, you look for that
<v Speaker 2>specific shade that says earth like. It's almost romantic.
<v Speaker 3>It is. It's a beautiful thought, but it's also well,
<v Speaker 3>it's a bit of a trap. A trap how so,
<v Speaker 3>it's a cognitive trap because it locks us into looking
<v Speaker 3>for a mirror. We're looking for ourselves, but ourselves today.
<v Speaker 3>It just assumes that habitable always equals blue, and that
<v Speaker 3>is exactly where we're going today.
<v Speaker 2>I want you to just for a second reimagine that dot.
<v Speaker 2>Forget the blue. Instead, picture of that pixel is a deep,
<v Speaker 2>vibrant purple.
<v Speaker 3>Or get this, What if the oceans on that dot
<v Speaker 3>weren't blue at all, but like a bright, almost neon green.
<v Speaker 2>And here's the kicker. This isn't science fiction. We're not
<v Speaker 2>talking about some far flown alien world.
<v Speaker 3>Yeah, no, not at all. We are talking about Earth.
<v Speaker 3>This is our own history. If alien astronomers had been
<v Speaker 3>looking at our planet at different times, they wouldn't have
<v Speaker 3>seen a pale blue dot.
<v Speaker 2>They have seen a purple world, oh or a green
<v Speaker 2>ocean world.
<v Speaker 3>And that simple fact that our planet changes its color
<v Speaker 3>over billions of years is at the heart of this. Well,
<v Speaker 3>this really intense debate happening inside NASA right now.
<v Speaker 2>It's a huge struggle. We're talking about giant space telescopes,
<v Speaker 2>million dollar budget fights, ancient bacteria, and even rocks that
<v Speaker 2>are trying to trick us exactly. We're looking at a
<v Speaker 2>new white paper that just came out January twenty twenty
<v Speaker 2>six on the Arts of pre Print Server. It's from
<v Speaker 2>the Living World's Working group.
<v Speaker 3>Which is a very very cool name for a committee
<v Speaker 3>of scientists.
<v Speaker 2>It sounds like a superhero team, doesn't it. But their
<v Speaker 2>job is actually really practical. They're trying to define the
<v Speaker 2>capabilities of the next great space telescope, the Happible World's
<v Speaker 2>Observatory or HWO.
<v Speaker 3>Right, and the argument they're making in this paper is,
<v Speaker 3>to put it simply, if we build this thing on
<v Speaker 3>the cheap, if we cut corners on the sensors to
<v Speaker 3>save a few.
<v Speaker 2>Billion dollars, which always happens.
<v Speaker 3>It always happens, then we might stare right at a
<v Speaker 3>living planet and have absolutely no idea what we're looking at.
<v Speaker 2>Or and I think this might be worse, we might
<v Speaker 2>stare at a dead, toxic rock and convince ourselves we
<v Speaker 2>found a jungle.
<v Speaker 3>That's the fear, that's the big false positive nightmare.
<v Speaker 2>So that's the mission today. We're going hunting for purple earths,
<v Speaker 2>green oceans, and the cosmic impostors trying to fool us.
<v Speaker 3>Let's do it.
<v Speaker 2>Okay, So before we even get to the cool biology,
<v Speaker 2>the purple bacteria and all that, we haven't talked about
<v Speaker 2>the machine, the tool, this Habitable World's Observatory.
<v Speaker 3>The HWO yeah.
<v Speaker 2>I mean, we've all been obsessed with the James Web
<v Speaker 2>Telescope JWST for the last few years. The images are
<v Speaker 2>just stunning. So why do we need another huge, expensive telescope.
<v Speaker 2>What can HWO do that Web can't.
<v Speaker 3>That is the multi billion dollar question, isn't it? And
<v Speaker 3>it really comes down to how they look at planets.
<v Speaker 3>JWST is an absolute marvel, don't get me wrong, but
<v Speaker 3>for exoplanets planets around other stars, it mostly uses a
<v Speaker 3>method called transit spectroscopy.
<v Speaker 2>Transit's okay, so that's the shadow method.
<v Speaker 3>Right, The shadow method exactly, you have to wait for
<v Speaker 3>a planet to pass directly in front of its star
<v Speaker 3>from our point of view.
<v Speaker 2>And as it does, a tiny bit of the starlight
<v Speaker 2>shines through the planet's.
<v Speaker 3>Atmosphere precisely like sunlight through a stained glass window, and
<v Speaker 3>by looking at what colors get filtered out, you can
<v Speaker 3>tell what gases are in that atmosphere. Oh, there's methane here,
<v Speaker 3>there's water, vapor. It's incredible, Like there's a butt, there's
<v Speaker 3>a big butt. You're only seeing the edges. You're basically
<v Speaker 3>looking at a backlit silhouette of the planet. You're sniffing
<v Speaker 3>its air, but you're not seeing its surface.
<v Speaker 2>You can't see the ground.
<v Speaker 3>You can't see the ground. The Habitable World's Observatory is
<v Speaker 3>designed to do something much much harder. It's designed for
<v Speaker 3>direct imaging.
<v Speaker 2>Which sounds simple. It just means taking a picture of
<v Speaker 2>the planet itself.
<v Speaker 3>It sounds simple. We take pictures all day, but the
<v Speaker 3>physics of it are just staggering. You're trying to photograph
<v Speaker 3>a tiny firefly floating right next to a giant, blinding searchlight.
<v Speaker 2>From miles and miles away.
<v Speaker 3>From light years away. The star is billions of times
<v Speaker 3>brighter than the planet. If you just point a telescope,
<v Speaker 3>the planet is completely lost in the glare.
<v Speaker 2>So how do you solve that? What's the trick?
<v Speaker 3>The trick is a very clever piece of engineering called
<v Speaker 3>a coronagraph. A coronagraph, Yeah, think of it this way.
<v Speaker 3>If you're outside and the sun is in your eyes,
<v Speaker 3>but you want to see, I don't know, a bird
<v Speaker 3>flying near.
<v Speaker 2>It, what do you do instinctively and put my hand
<v Speaker 2>up block the sun with my thumb.
<v Speaker 3>Exactly, you create a tiny artificial eclipse just for your eye.
<v Speaker 3>A coronagraph is a super high tech hand inside the telescope.
<v Speaker 3>It's a system of masks and mirrors that physically block
<v Speaker 3>the light from the star.
<v Speaker 2>So it creates a little shadow right where the star is.
<v Speaker 3>A perfect little shadow. It suppresses that glare by an
<v Speaker 3>insane amount, like it blocks ninety nine point nine percent
<v Speaker 3>of the starlight, and suddenly the faint little speck of
<v Speaker 3>light reflecting off the planet next to it can actually
<v Speaker 3>be seen.
<v Speaker 2>And that's the revolution, because if you can block the star,
<v Speaker 2>you're not just seeing the atmosphere anymore.
<v Speaker 3>Now you're seeing the surface.
<v Speaker 2>You're seeing the light bouncing off the continents, off the oceans.
<v Speaker 2>You can actually see its color.
<v Speaker 3>And that's where all the trouble starts because seeing color
<v Speaker 3>sounds easy, but to do it from that distance, you
<v Speaker 3>need incredibly clean data. The whole point of this new
<v Speaker 3>white paper is that the aged needs an exceptionally high
<v Speaker 3>signal to noise ratio signal to noise.
<v Speaker 2>We talk about that in audio production. So it's about clarity.
<v Speaker 3>It's all about clarity. It's not just about getting more light,
<v Speaker 3>it's about getting clean light. Imagine you're at a really
<v Speaker 3>loud concert and someone across the room is trying to
<v Speaker 3>whisper a secret password to you, Okay, The loud music
<v Speaker 3>is the noise, all the stray light from the star,
<v Speaker 3>from dust in space, even heat from the telescope itself.
<v Speaker 3>The whisper is the signal, that little sliver of colored
<v Speaker 3>light that might indicate life.
<v Speaker 2>And if the signal to noise is low, the music
<v Speaker 2>is too.
<v Speaker 3>Loud, you can't hear the password. You might hear a murmur,
<v Speaker 3>You might think they said the right word, but you
<v Speaker 3>can't be sure. The scientists are saying they need a
<v Speaker 3>system so quiet, so sensitive that they can pick out
<v Speaker 3>that whisper with total confidence.
<v Speaker 2>And this gets us back to the horse trading you mentioned,
<v Speaker 2>because making a quiet telescope is.
<v Speaker 3>Expensive, unbelievably expensive. Every little bit of improved performance costs
<v Speaker 3>millions or tens of millions, and the financial managers at NASA,
<v Speaker 3>their job is to look at the plans and say, Okay,
<v Speaker 3>do you really need the deluxe sensor package. Can't you
<v Speaker 3>just make do with the standard one cage?
<v Speaker 2>Just fix it in photoshop later.
<v Speaker 3>Exactly, And this paper from the Living World's Group is
<v Speaker 3>their response. It's them saying, look, this isn't a luxury feature,
<v Speaker 3>this isn't just gold plating. If we don't have this
<v Speaker 3>specific capability, the entire mission could fail. We won't be
<v Speaker 3>able to hear the whisper.
<v Speaker 2>Okay, so let's get into what they're trying to hear.
<v Speaker 2>What's the whisker? If an alien astronomer is looking at
<v Speaker 2>Earth right now, what's the gold standard signal that screams life.
<v Speaker 3>For modern Earth? The clearest, most unambiguous surface biosignature is
<v Speaker 3>something called the vegetation red edge.
<v Speaker 2>The red edge, it sounds like a spy movie, A.
<v Speaker 3>Cliff is actually the best way to think about it.
<v Speaker 3>So we all know plants are green because chlorophyll absorbs
<v Speaker 3>red and blue light for photosynthesis.
<v Speaker 2>Right right, and it reflects the green light, which is
<v Speaker 2>why we see it as green.
<v Speaker 3>But that's not the whole story. There's something else happening
<v Speaker 3>that our eyes can't see. Plants are also reflecting a
<v Speaker 3>huge amount of near infrared light.
<v Speaker 2>Okay, why, what's the evolutionary advantage there?
<v Speaker 3>It's a radiator, it's thermal regulation. Infrared light is basically heat.
<v Speaker 3>If plants absorbed all that infrared energy from the sun,
<v Speaker 3>they literally cook themselves from the inside out.
<v Speaker 2>Ah, So they need to get rid of it.
<v Speaker 3>They need to get rid of it fast. So they
<v Speaker 3>evolved this amazing trick where their cell structures act like
<v Speaker 3>perfect mirrors for a near infrared light. They just bounce
<v Speaker 3>it right back into space.
<v Speaker 2>That's genius, it is.
<v Speaker 3>And if you plot this on a graph of light,
<v Speaker 3>a spectrogram, it creates this incredibly dramatic feature. The brightness
<v Speaker 3>is low in the red part of the spectrum because
<v Speaker 3>the plants are eating that light. And then as soon
<v Speaker 3>as you cross over into the near infrared, boom, the
<v Speaker 3>line shoots straight up like a vertical wall, a cliff,
<v Speaker 3>a cliff. That sharp sudden jump is the vegetation red edge.
<v Speaker 2>And rocks don't do that.
<v Speaker 3>Rocks and sand and dirt they don't do that. Their
<v Speaker 3>reflection spectra are usually smooth slopes, they don't have sharp edges.
<v Speaker 3>If you see that cliff, it's one of the strongest
<v Speaker 3>signs of widespread complex life you could ever hope for.
<v Speaker 2>But and I'm sensing the catch here, the thing the
<v Speaker 2>white paper is worried about. You can only see that
<v Speaker 2>cliff if your camera can see into the infrared.
<v Speaker 3>There's the catch. If the budget committee says, hey, those
<v Speaker 3>near infrared sensors are too complex, too expensive, let's just
<v Speaker 3>stick to the visible light our eyes can see. Then
<v Speaker 3>you completely miss the red edge.
<v Speaker 2>The cliff is invisible to you.
<v Speaker 3>It's invisible. You could be looking at a planet covered
<v Speaker 3>in the Amazon rainforest and it would just look like
<v Speaker 3>a dark, unremarkable smudge. You miss the smoking gun.
<v Speaker 2>So that's argument number one for the expensive model. We
<v Speaker 2>need infrared to see earth like life today. But the
<v Speaker 2>paper goes deeper, doesn't it, because looking for modern Earth
<v Speaker 2>isn't enough.
<v Speaker 3>Not even close. I mean, this is where it gets
<v Speaker 3>really mind bending for me. We're so biased towards green chlorophyll,
<v Speaker 3>but chlorophyll is in the grand scheme of things, a
<v Speaker 3>fairly recent invention for a huge chunk of our planet's history.
<v Speaker 3>The world wasn't green, it was purple. It was purple.
<v Speaker 2>The purple Earth hypothesis. I love this, So take us back.
<v Speaker 2>What's going on purple Earth.
<v Speaker 3>We're talking maybe three billion, two point five billion years ago.
<v Speaker 3>The most advanced life forms on the planet were these
<v Speaker 3>single celled organisms purple and oxygenic phototrufs.
<v Speaker 2>Okay, that's a mouseful it is.
<v Speaker 3>Let's just call them purple bacteria. The key thing is
<v Speaker 3>they didn't use chlorophyll for photosynthesis. They used a different
<v Speaker 3>kind of pigment called retinal.
<v Speaker 2>Retinal wait as in this stuff in our retinas in
<v Speaker 2>our eyes, very.
<v Speaker 3>Very similar chemical structure, the same pigments your eyes used
<v Speaker 3>to detect light. These ancient bacteria used to harvest energy
<v Speaker 3>from the sun, and they work differently from chlorophyll. Chlorophyll
<v Speaker 3>absorbs red and blue, reflects green. Retinal is basically the opposite.
<v Speaker 3>It's most efficient at absorbing green and yellow light, which
<v Speaker 3>by the way, is the peak of the Sun's energy output.
<v Speaker 2>So it's absorbing the most powerful part of the sunlight.
<v Speaker 2>And if it absorbs green.
<v Speaker 3>Flex the other parts. It reflects red and blue light.
<v Speaker 2>And if you mix red and blue paint you get you.
<v Speaker 3>Get purple, a deep, rich purple.
<v Speaker 2>So for a billion years, maybe more, any continents or
<v Speaker 2>shallow coastal areas on Earth would have been covered in
<v Speaker 2>these vast purple mats of bacteria.
<v Speaker 3>And this isn't just a theory. We still have them.
<v Speaker 3>If you go to super salty places like the Great
<v Speaker 3>Salt Lake or certain salt flats, you can see these
<v Speaker 3>organisms called halo bacteria. They turn the water that shocking
<v Speaker 3>brilliant pink or purple color.
<v Speaker 2>So we can see what ancient Earth looked like today
<v Speaker 2>we can.
<v Speaker 3>And here's the number from the paper that just flings me.
<v Speaker 3>This purple Earth phase might have lasted for nearly one
<v Speaker 3>point five billion years.
<v Speaker 2>That's staggering. That's more than twice as long as complex
<v Speaker 2>animals have even existed.
<v Speaker 3>Exactly, for a huge percentage of the time that Earth
<v Speaker 3>has been alive, it was a purple planet. So now
<v Speaker 3>apply that to the telescope problem.
<v Speaker 2>Okay, So if HWO is scanning the galaxy and it
<v Speaker 2>finds a planet that happens to be in its own
<v Speaker 2>own purple phase, right now.
<v Speaker 3>What do we see.
<v Speaker 2>Well, if we don't have the right sensors, we see nothing.
<v Speaker 3>We see nothing. These purple bacteria, they're retinal pigments. They
<v Speaker 3>absorb light well into the infrared, so their spectral signature,
<v Speaker 3>their edge is different from chlorophylls. If we build a
<v Speaker 3>telescope that is only looking for the red edge of
<v Speaker 3>modern plants.
<v Speaker 2>We're wearing the wrong color glasses.
<v Speaker 3>You're wearing the wrong glasses. You would look at a
<v Speaker 3>world that is absolutely teeming with life, a thriving global biosphere,
<v Speaker 3>and your multi billion dollar instrument would tell you it's
<v Speaker 3>a dead rock.
<v Speaker 2>That is the ultimate nightmare scenario. We spend twenty years
<v Speaker 2>building this thing pointed at a second Earth and just
<v Speaker 2>completely fail to recognize it.
<v Speaker 3>That's the argument. The Living World's Working Group is basically screaming,
<v Speaker 3>you cannot design this machine just to find us today.
<v Speaker 3>You have to design it to find who we were yesterday.
<v Speaker 3>Because statistically, for any given planet, it might be more
<v Speaker 3>likely to be in its purple phase than its green phase.
<v Speaker 2>Okay, so we've got purple Earth. But the story doesn't
<v Speaker 2>just jump from purple to the green forest we see today.
<v Speaker 2>There was an intermediate step in the outline.
<v Speaker 3>There was a middle chapter, the green Ocean hypothesis.
<v Speaker 2>Where the oceans themselves turned green.
<v Speaker 3>Yes, this is a fascinating period geologically and biologically. We're
<v Speaker 3>talking about the rchae and eon. So maybe between four
<v Speaker 3>and two point five billion years ago, the world was different.
<v Speaker 3>The atmosphere had no oxygen.
<v Speaker 2>So what made the water green? Was it some kind
<v Speaker 2>of early algae?
<v Speaker 3>No? Not, At first, it was the rock the planet's geology.
<v Speaker 3>The oceans were full of dissolved iron that was being
<v Speaker 3>pumped out of hydrothermal events. On the seafloor, specifically.
<v Speaker 2>Ferric iron, and that colors the water.
<v Speaker 3>It does. Ferrisc iron in a solution is really good
<v Speaker 3>at absorbing light at the blue and red ends of
<v Speaker 3>the spectrum, but it doesn't absorb green light very well.
<v Speaker 2>So it reflects the green the ocean itself. Just the
<v Speaker 2>water and iron would have looked green, that.
<v Speaker 3>Kind of murky olive green probably, But then life adapts.
<v Speaker 3>Evolution is always an opportunist. You have these early cyanobacteria
<v Speaker 3>floating in the water. They need sunlight, but the water
<v Speaker 3>they're living in is filtering out all the good red
<v Speaker 3>and blue light, so.
<v Speaker 2>The only light that's making it down to them is
<v Speaker 2>the green light that the iron isn't absorbing the leftovers.
<v Speaker 3>So what do they do? They evolve a new tool.
<v Speaker 3>They develop special accessory pigments called phycobilins that are perfectly
<v Speaker 3>tuned to capture and use green light for photosynthesis.
<v Speaker 2>It's like they're tuning their antenna to the only radio
<v Speaker 2>station that's.
<v Speaker 3>Broadcasting perfect analogy, and so you get this layered effect.
<v Speaker 3>You have a geological green signal from the iron and
<v Speaker 3>then a biological green signal from the bacteria living in it.
<v Speaker 2>Now from the telescope's point of view, that's got to
<v Speaker 2>be confusing.
<v Speaker 3>It's extremely confusing because if you just look at the
<v Speaker 3>overall color, a bionet with a green ocean full of
<v Speaker 3>cyanobacteria looks very, very similar to a planet with continents
<v Speaker 3>covered in green forests.
<v Speaker 2>So if we saw that, would it even matter? I mean,
<v Speaker 2>green is green? Life is life? We pop the champagne, right,
<v Speaker 2>I mean yes and no.
<v Speaker 3>On the one hand, any row bust green signal is
<v Speaker 3>a huge deal, But scientifically we'd want to know what
<v Speaker 3>we're looking at. Is this a primitive oxygen poor world
<v Speaker 3>with simple bacteria or.
<v Speaker 2>Is it a mature, oxygen rich world with complex plants.
<v Speaker 3>Those are two fundamentally different stages of planetary evolution. Telling
<v Speaker 3>them apart requires incredibly high spectral resolution. You need to
<v Speaker 3>be able to see the subtle little bumps and wiggles
<v Speaker 3>in the spectrum that differentiate a phycobilin pigment from a
<v Speaker 3>chlorophyll pigment.
<v Speaker 2>So again it comes back to the quality of the instrument.
<v Speaker 2>Don't give us a blurry, low res camera exactly.
<v Speaker 3>But it gets even more complicated because sometimes a color
<v Speaker 3>that looks like life isn't life at all. Sometimes it's
<v Speaker 3>just a rock trying to fool you.
<v Speaker 2>This is the part that gives me anxiety. The mimics,
<v Speaker 2>the false positives.
<v Speaker 3>This is the core of the engineering argument in the paper.
<v Speaker 3>It's about being sure. We are so desperate to find life,
<v Speaker 3>there's a huge risk of confirmation bias. We want to believe.
<v Speaker 3>The universe, however, is full of minerals that can look
<v Speaker 3>an awful lot like biology.
<v Speaker 2>So let's go through the list of suspects. What's mimic
<v Speaker 2>number one?
<v Speaker 3>The most obvious one is iron oxide rust Mars. Mars
<v Speaker 3>is the poster child. It's the red planet because it's
<v Speaker 3>covered in rust. Spectrally, rust creates what's called a red slope.
<v Speaker 3>It just reflects more and more light as you go
<v Speaker 3>from green to red to infrared.
<v Speaker 2>And if you have a blurry instrument, a gentle slope
<v Speaker 2>can look a lot like a sharp edge.
<v Speaker 3>They can blur together. Think about looking at a ramp
<v Speaker 3>versus a single step from really far away. If your
<v Speaker 3>vision is bad, they can look the same. You could
<v Speaker 3>absolutely mistake a dead, rusty desert planet for a world
<v Speaker 3>covered in vegetation.
<v Speaker 2>So how do you tell them apart.
<v Speaker 3>You need high resolution. You need to be able to
<v Speaker 3>see the sharpness of the feature. Biology creates sharp, well
<v Speaker 3>defined edges. Geology is usually smoother, more sloped. You need
<v Speaker 3>an instrument that can tell the difference.
<v Speaker 2>Okay, so rust is a big one, but the paper
<v Speaker 2>mentioned another mineral that was much more exotic. Cinebar.
<v Speaker 3>Cinebar. Yeah, mercury sulfide. It's this brilliant red mineral, and
<v Speaker 3>it's mercury.
<v Speaker 2>It's incredibly toxic.
<v Speaker 3>You would not want to land on a planet made
<v Speaker 3>of cinebar. But here's the universe playing a cruel joke
<v Speaker 3>on us. Cinebar has a spectral feature. It has a
<v Speaker 3>very strong, very sharp reflective edge.
<v Speaker 2>It's like plants.
<v Speaker 3>Doo, just like plants, but there's one tiny critical difference.
<v Speaker 3>The vegetation red edge happens at a wavelength of about
<v Speaker 3>seven hundred animeters. Okay, the cinnabar edge happens at about
<v Speaker 3>six hundred animeters.
<v Speaker 2>That's one hundred animeters. That sounds like almost nothing.
<v Speaker 3>It is almost nothing. And if your telescope has low
<v Speaker 3>spectral resolution, if your pixels are too fat, then six
<v Speaker 3>hundred nanimeters and seven hundred animeters can fall into the
<v Speaker 3>same data bin, they blur together into one signal.
<v Speaker 2>So imagine the press conference. NASA gets up and says,
<v Speaker 2>we found it a planet with a clear biological edge.
<v Speaker 2>It's covered in red forests.
<v Speaker 3>And then ten years later a better instrument goes up
<v Speaker 3>and we realize, oh, whoops, it's actually a giant poison
<v Speaker 3>us mercury rock.
<v Speaker 2>That would be devastating.
<v Speaker 3>That is the nightmare. That is why they are fighting
<v Speaker 3>for this high resolution. They're saying, we have to be
<v Speaker 3>able to tell the difference between six hundred and seven
<v Speaker 3>hundred nanimeters with absolute certainty. We need to be able
<v Speaker 3>to distinguish a tree from a toxic rock.
<v Speaker 2>Wow. Okay, and there was one more mimic, right, sulfur
<v Speaker 2>elemental sulfur.
<v Speaker 3>Yeah, it has its own edge, but it's down around
<v Speaker 3>four hundred and fifty to five hundred nanometers. It's a
<v Speaker 3>little easier to spot because it's further away from the
<v Speaker 3>vegetation signal, but the principle is the same. A planet
<v Speaker 3>could have a weird mix of minerals, maybe some sulfur
<v Speaker 3>and some cinnabar.
<v Speaker 2>And with a low res instrument, that combination of signals
<v Speaker 2>could mash together into something that looks convincingly and incorrectly biological.
<v Speaker 3>You got it. It's not that the universe is intentionally
<v Speaker 3>trying to trick us. It's just that chemistry is complex,
<v Speaker 3>and biology is just a very specific, very organized form
<v Speaker 3>of mistry. To find it, you need tools that are
<v Speaker 3>precise enough to measure that specific or organization.
<v Speaker 2>So this all brings us back to the present day,
<v Speaker 2>to the horse trading. We have this paper the scientific argument,
<v Speaker 2>but it's really it's a negotiating tool.
<v Speaker 3>It's absolutely a negotiating tool. The Living World's Working Group
<v Speaker 3>is laying out its case for the budget committees at
<v Speaker 3>NASA and in Congress.
<v Speaker 2>And the case is basically, if you cut our budget
<v Speaker 2>and force us to buy the cheap camera, we.
<v Speaker 3>Will confuse mercury for forests, We will miss entire purple biospheres.
<v Speaker 3>The mission you're paying for will not be the mission
<v Speaker 3>you get.
<v Speaker 2>So what's the wish list summed up?
<v Speaker 3>It's three things. One high signal to noise so we
<v Speaker 3>can actually see the faint light from the surface. Two
<v Speaker 3>wide spectral range from visible light through near infrared, so
<v Speaker 3>we can see both the red edge and the signatures
<v Speaker 3>of purple earths. And three high spectral resolutions, so we
<v Speaker 3>can tell the difference between a real biological edge and
<v Speaker 3>a geological mimic like cinebar.
<v Speaker 2>And what's the reality, what's likely to happen. The sources
<v Speaker 2>mentioned recent cuts to other big NASA programs.
<v Speaker 3>The reality is that the budget is ex extremely tight.
<v Speaker 3>It's very unlikely they'll get everything on their wish lists.
<v Speaker 3>They are going to be compromises.
<v Speaker 2>But the compromise here feels so much more significant than
<v Speaker 2>you know, getting a slightly smaller hard drive.
<v Speaker 3>It is a compromise here fundamentally changes the nature of
<v Speaker 3>the mission. It takes you from a mission of discovery
<v Speaker 3>and confirmation to a mission of discovery and ambiguity.
<v Speaker 2>And nobody wants to spend twenty years and ten billion
<v Speaker 2>dollars just to get a maybe.
<v Speaker 3>Exactly, to spend all that time and effort to point
<v Speaker 3>to a pale, purple dot and say, well, that might
<v Speaker 3>be life, but it also might be a rock, that
<v Speaker 3>would be an excruciating result. The scientists are arguing it's
<v Speaker 3>better to build the yes or No machine, even if
<v Speaker 3>it costs more.
<v Speaker 2>Upfront, because we might only get one shot at this.
<v Speaker 3>We will only get one shot at this in our lifetimes.
<v Speaker 3>This is the flagship observatory for the next generation. We
<v Speaker 3>are building the eyes that our children and grandchildren will
<v Speaker 3>use to explore the galaxy.
<v Speaker 2>And if we build them with cataracts on day one
<v Speaker 2>to save a bit of money, they're going to be
<v Speaker 2>the one squinting at the blurry data.
<v Speaker 3>That's the stakes. This paper is a plea to look
<v Speaker 3>at the long game.
<v Speaker 2>So we've gone all the way from the pale blue
<v Speaker 2>dot to purple bacteria, green oceans, and toxic mimics. It's
<v Speaker 2>a much more complicated picture of what life might look.
<v Speaker 3>Like it really is. It shows that to find life
<v Speaker 3>out there, we first have to really really understand the
<v Speaker 3>deep history of life right here.
<v Speaker 2>We have to remember our own purple past.
<v Speaker 3>Mm hmm, and we have to be open to the
<v Speaker 3>idea that pale blue is just one outfit in a
<v Speaker 3>very large cosmic wardrobe.
<v Speaker 2>So as we wrap up, I want to leave everyone
<v Speaker 2>listening with a final thought on this. We always talk
<v Speaker 2>about the cost of these huge projects, billions of dollars
<v Speaker 2>for a telescope, A lot of money, it is, but
<v Speaker 2>think about the cost of not doing it right. Imagine
<v Speaker 2>we build the cheaper version, we scan a thousand worlds
<v Speaker 2>and we find nothing but ambiguous smudges, we might conclude
<v Speaker 2>we're alone.
<v Speaker 3>Right, we'd get a null result and just assume there's
<v Speaker 3>nothing there.
<v Speaker 2>But what if we weren't alone. What if the galaxy
<v Speaker 2>is filled with purple worlds and we just didn't buy
<v Speaker 2>the right pair of glasses to see them. What's the
<v Speaker 2>higher cost, the cost of the telescope or the cost
<v Speaker 2>of staying alone in the universe when we didn't have
<v Speaker 2>to be.
<v Speaker 3>Yeah, that's the question.
<v Speaker 2>To look right at a living planet and see a
<v Speaker 2>dead rock because of a budget decision made decades earlier.
<v Speaker 2>I mean, that feels like a tragedy on a galactic.
<v Speaker 3>Scale, the ultimate missed connection.
<v Speaker 2>Here's hoping the living world's working group wins their fight.
<v Speaker 2>Thanks so much for walking us through.
<v Speaker 3>All this My pleasure. Keep looking up and maybe look
<v Speaker 3>for purple sass s