Strongest Evidence for Alien Life? (Mars, K2-18b & JWST)

0:00Hello internet, this is your captain speaking, Lester Nare, joined as always by my co-host and our resident PhD, Krishna Choudhary. This is From First Principles and we are a code red today, as you can see from our background, we had to do this emergency pod as we saw this massive breaking news coming out of NASA of the strongest evidence yet for biosignatures on Mars. So, we are going to do a deep dive on alien life covering three stories starting with that latest breaking news and paper from NASA, which has made waves across the media space, and then we're going to go back for our second story to look at a story from April of this year out of Cambridge,

0:40which also claimed to have the strongest evidence yet of life on a distant planet, not Mars, and we'll wrap up with some new discoveries or at least new analysis from James Webb about the atmosphere on exoplanets that are habitable in the way we think of life. This is going to be a fantastic episode. Let's jump in.

1:15My friend, how's it going? Episode 8. We're cooking a little emergency pod situation. >> yeah. Uh we both woke up this morning. I immediately texted you as soon as I saw the news. Yeah. Uh Press conference and everything. >> Everything. Every NASA X Twitter account posted about this. >> Yeah. Obviously, it broke on every science blog and everything. >> Yeah. Because we've sort of had some evidence, but we wanted to make sure and NASA felt it was good enough >> Yeah. to now have the acting administrator of NASA, Sean Duffy, uh

1:57come out and do a victory lap >> Mhm. that we we we might have got them. Yeah. We maybe got them. >> That's what they say. So, let's let's start with the breaking news from today. >> Yeah. Um I watched most of the press conference. Um I'd been following this particular, let's say, sample because at the time it was brought up and people were like, "Oh, here we go." >> Yeah. Um but at the same time, everyone was telling me, "Well, the Hillary Clinton administration said there was strong evidence for biosignatures on Mars 20 years ago." So, what's actually different? Um well, this time it seems it seems to be a little bit better than the one that was 20 years ago, but we're actually going to get

2:37back to that as part of our story, okay? >> So, it's it seems to be a landmark discovery. Okay. Um it is what they're characterizing as a potential biosignature. >> Ah, potential. And um not a full biosignature. A potential biosignature means possibilities that this was a signature of life. Mhm. But in order to actually really nail it down, what we're going to need is the sample to come back to Earth. Fair. >> And then actually have lab testing with things like electron microscopes and all that other kind of stuff. So, we didn't discover the underground cities and ancient structures on Mars.

3:17>> no no channels, no like Martians. >> Okay. Um it seems to be a tantalizing sign that there might have been microbial life on Mars way, way back. Back when Mars looked kind of like Earth. Not Earth now, but Earth prehistoric, like right after formation. So, the way the solar system formed, you know, um there was some giant gas nebula cloud that started spinning. The sun was born. Um there were outcroppings of small nuclei that became the planets, the rocky planets on the inside. The solar radiation kind of blew out all the lighter gases, so the lighter gases of hydrogen and helium

3:59formed the outer planets of Jupiter, Neptune Saturn. >> giants. >> Right? And yeah, the gas giants. So, right after that, you know, for about a billion years, Mars and Earth were both in the habitable zone of the sun. Mhm. Okay? The reason why Mars looks so different today compared to Earth is because it's just smaller and so it couldn't hang on to its atmosphere for long enough. And if you can't hang on to your atmosphere for long enough, then pressure decreases like crazy. And if the atmospheric pressure decreases, then you're no longer get going to be able to sustain liquid water. Mhm. Right? And liquid water is something that we're pretty sure is essential for life.

4:42>> Fundamental. >> Okay. Fundamentally, we need liquid water as this kind of universal solvent >> Mhm. that creates the kind of biochemistry that would be required for something as complex as life. Asterisk, as we know it. As we know it, yes yes. Obviously, there could be other forms. I mean, there's there's people talking about life on the clouds of Venus, on the clouds of Jupiter, and all sorts >> But we haven't seen it. random stuff, but we haven't seen it. There could be life in the methane lakes of Titan, but we haven't seen it. >> be a billion dollars buried in my backyard, but we haven't seen it. >> haven't seen it. And so, as far as we can tell, we need life we need water to create life, right? And anywhere there

5:23is liquid water on Earth, there seems to be life. >> Mhm. Even if it's like near boiling. >> Mhm. Like near Yellow Sto- in Yellowstone, there's life there, right? So, it seems it seems like the the one criteria is liquid water. >> Right. You don't even need oxygen. Mhm. need liquid water. >> Mhm. Um and some source of energy. In the case of Mars, that could have just been the sun or like geological processes on Mars. Right. >> Or like the already present compounds on Mars that are somehow, you know, packed with energy that life can then then exploit to metabolize. >> So, that's sort of the the Mars that NASA's been obsessed with Right. >> longest time, okay? >> This primordial baby Mars that had

6:07liquid water. >> Right. We know that now from our several missions there. Actually, the Curiosity rover, which was launched in the 2010s, that had a primary mission of trying to find habitable qualities in Mars. It wasn't trying to look for signatures of life. It was just trying to see, okay, was Mars early in its heyday was Mars somewhere that could house life. >> Mhm. And the Curiosity rover found signs of liquid water. >> Mhm. Right? And so, everyone was really excited. It's like, okay, there's liquid water. The next thing we should do is try to equip um a laboratory on Mars that can run around like a rover

6:48and also have all of the tools necessary to sort of do these chemical analyses on the spot and try to look for biosignatures. And that's where the Perseverance rover came in. This This makes sense because the idea is the sort of the flight time and flight windows from Earth to Mars are both infrequent and it takes very long. >> Yeah. And so, to be able to ascertain before you spend the time and money Yeah. to send something back, we want to kind of do a spot check on site. >> Yeah. And honestly, like, you know, when the Mars Perseverance rover was launched, I think it was in 2020, um during the first Trump

7:28administration, there was a there was a 5-year search to figure out where to put it. Okay. >> Okay? Right. Because you only got one thing. This thing's the size of an SUV. You got one shot. JPL is worried about, okay, once we have a once we have a spot, how do we get it down there? >> Jet Propulsion Lab for those who don't know. >> That's the Jet Propulsion Lab out in Pasadena, um one of Caltech's little side projects. Um and you know, so there was there were 60 different candidate sites Okay. that they were trying to figure out. >> had a Mars Love Island. >> Yeah, yeah. And then and then there was an international collaboration to try and figure out what is the best place to go, Right. okay? And what they settled on was this place called the Jezero

8:09crater. Okay. Okay? It's this giant crater. It's about 25 miles across. And from we know from the Mars Reconnaissance Orbiter, which is something that just like goes around Mars, has all these like instruments for infrared, visible, from that we can figure out composition of the of the soil. >> Yep, the surface. Right? The surface chemistry. From that, we had figured out, okay, this is a pretty promising candidate. >> Mhm. Um also, and I just want to because the idea is we're looking for these ingredients that we view as necessary for being valuable to life being able to exist. >> Yeah. We have these tools to detect what's there, and then so we look for the perfect match for those two. >> Exactly, yeah. And we got like we got

8:51about 60 candidates. And then this one was really nice because it's a crater that had um that we're pretty sure had like a lake. >> Mhm. So, it's like one of those crater lakes you can you can think of as that. Um and there was a river delta system Okay. that was going into it. So, there's these beautiful like traces of like literally valleys and like river valleys going into this crater. So, you know, there's a lot of really nice sedimentary rock that's going to be there, and you're going to see if there's life on Mars, that's a really good place to go, okay? Mhm. So, um NASA JPL decided, okay, we're going to go to the Jezero crater. They landed it there, which is a feat in itself, >> right? This is a SUV packed with like a

9:33whole building's worth of lab equipment, right? That that like you're you're trying to drop in the lab equipment has to be resilient to the heartache of getting off the Earth, >> Yes. going all the way to Mars, then doing a landing on Mars, right? And then everything working >> Everything works. >> And I it's still just such a testament to our engineering capabilities that we are able to do this in one shot, and like we're just like really good at it at this point, right? At this point if like JPL fails and like it crashes, we'd be like, "Oh, you guys suck." Like what are you But you know, like it's actually insane how many how many like how many failure modes there are and

10:15none of them ever fail. Like James James Webb Space Telescope, there was so many failure modes and it just like didn't fail cuz like the NASA engineers are that good, right? And other countries are like like, you know, they're crashing on the moon. Right. Right, right. They're not This is Mars, dude, with an atmosphere and stuff. Like it's crazy. Yeah. M A S Red rocks. Exactly. So we've been obsessed with Mars for a long time. That's been sort of our our go-to place to try and find signatures of alien life. Right? Even if it's microbial, we want to see that like, you know, even in terms of life that we're not alone. I mean, here's the

10:55thing. If the part of the point is if we are able to even confirm, which NASA says we're on the road to, that there is microbial life, not intelligent life, on the nearest neighbor that we have in the vastness that is the universe. That has implications in and of itself even if it's simply microbial life. >> Yeah, yeah. And even if it was something that was there only like 3 billion years ago, right? The fact that it was there meaning that like the fact that like a planet that was habitable just had life, that's like two data points. Right, right. And all both have have life, right? I mean, even with Earth's data point like

11:35the fact the fact of the matter is as soon as Earth was habitable, we have fossils dating back to like that. Like before photosynthesis, we have fossils that say, "Yeah, we have we had life like basically as soon as the Earth cooled and we had water." Right. And if we see that now in two locations, >> Yeah, then it's like, "Okay, maybe it's actually look pretty ubiquitous phenomenon all across the universe." And that once you get to the conditions that support life to exist, it does arise not at a low probability but at a some somewhat higher probability than we may currently sort of ascribe to the ability for life to Yeah. Arise. Yeah. Yeah. So so you know, it'd be it'd be a huge deal if

12:16we find like >> The point is this is going to be a big deal. >> Yeah, this is going to be a really big deal. And this is only half the story because obviously, you know, however much we pack onto the Perseverance rover, it's not a lab on Earth, right? We can't put a scanning tunneling microscope up there, okay? That's all Even JPL guys will be like, "Guys, come on." Right. We can't It's literally easier to go and get the stuff back. Right? So it's like, "Okay, we're we're making this calculation. Like why don't we just go and get it and then and then just do it here, right?" Yeah so so this is the Jezero crater. Yes. Um Perseverance was parked right on the

12:57outskirts, did a little bit of traversing around there, and then it went down this valley down this river valley towards the crater. Um it went to the spot called the Bright Angel formation, which is right in the Neretva valley, okay? It's this like river valley that goes into the crater, okay? And right over there is something that's really nice because you've got the sedimentary rock on the western edge of this crater, okay? And because it's a driver river valley, you're going to have potentially signs of stuff that lived in that water, right? And it's going to leave its markings in the rock, okay? Now, the

13:38best thing to do would be to just search for organic compounds. Okay. Right? That'd be amazing. Like just carbon like we we find glucose, we're like, "Okay." We got glucose. Okay? The problem with finding organic compounds on Mars is it's really hard. One is because it's got no atmosphere and very little magnetic field, there's going to be a lot of radiation from the sun. And that radiation from the sun over the past 3 billion years is just going to completely wreck these organic compounds, right? On the other on top of that, you've got these things called perchlorates with which are chemicals that are highly corrosive. So they're going to react with organic chemistry and you're not going to you're not going to see like you're not going to go see like amino acids like in abundance. You might see them in trace amounts, but you're not going to like,

14:19you know, find amazing signatures like that. >> The idea is the environment because of the atmosphere dissipation basically will have destroyed any active evidence of these organic compounds. >> Yeah, yeah, exactly. So what you want to do is you want to look for inorganic compounds that have signatures of being made by organic chemistry, okay? And so that's what the story is, okay? This story is focusing on two two classes of compounds, iron phosphates and iron sulfides. So that's iron with phosphate, which is like an SO4, or just

15:00an S, or you can have like phosphate sorry, iron and sulfur, which is the SO4, or you can have iron phosphate, okay? And phosphorus and sulfur phosphorus specifically very much something that is associated with life on Earth, okay? So finding these things is very very nice. And that's what they found. They found these iron phosphates and iron sulfides in the rock at this Bright Angel formation, okay? And the way that they the way that they found these is very conspicuous, okay? It's very weird. It's not like part of the rock itself,

15:41what they what they found was so that you've got this like substrate of rock, which is this mud clay, okay? It's got a lot of iron. And then you have these like little they they call them poppy seeds and leopard spots, okay? They're like little tiny like like beads of stuff. Um I get it if I if for all the New Yorkers, you know, poppy seed bagel is heresy when you get your bacon, egg, and cheese if you put it on a bagel. But like it would be like looking at a bagel these little speckles. >> Exactly, yeah. It'll be like looking at except now it's like this clay rock. Yeah, and then you've got these like speckles, right? And these speckles have these particular minerals that are

16:22very exciting to us, okay? And the other thing that they found was that So the these speckles have these minerals, right? Of iron sulfide and and iron phosphate. And the only way that these things could have really happened is through something called a redox reaction. If you've if you know from this is basic chemistry, you have this thing called the oxidation reduction process, okay? These reactions are basically ways to transfer electrons from one thing to another. And so you reduce it by taking in electrons, right? Usually it involves oxygen, which is called why it's called oxidation, but it doesn't always have to. It's really just a transfer of electrons. And we know that organic

17:02chemistry does this really well, okay? And what they found was like in the underlying so in the underlying clay, they could actually see carbon. Okay? So there was carbon there. And the gradient of carbon was coinciding with how much of this stuff you were seeing, okay? Do you see what I'm saying? So now it's getting exciting. It's like it's like there's a gradient of carbon, which means maybe there was more life on this side than on this side. And so and the density of this of this of this iron phosphate iron phosphate, which is very or like, you know, on Earth associated with life, is tracking. It's correlated to the

17:44gradient >> Yeah, of the underlying carbon. Right? So now it's like, "Okay, this is pretty nice." Mhm. Uh data points >> Yeah, yeah. correlating very strongly that we associate with like with with organic chemistry. And so and so that was and so the idea is you have the starting material, which is this oxidized mudstone, right? Which is rich in iron 3, which is an ion of iron. That means that three electrons are missing. And then what you do is you have organic carbon, and then that acts like a electron donor to this whole process. And then you have the iron 3 and the SO4, which is an ion that's also found in

18:24this organic inorganic compounds. And then that gets converted into iron 2 and just sulfide, which is just the sulfur atom. So the oxygen goes away. That chemistry is very very organicky. Like that chemistry is very life life adjacent if I if I may say. Right? So so that's that's the whole point. Everyone's like really excited about this. And and you know, one of the impressive things is that we can do all of this on Mars, right? All of this toolkit is on that SUV. The Mars Perseverance rover. Which is crazy. That it's got this one instrument called PIXL, P I X L, for Planetary Instrument for X-ray

19:05Lithochemistry. Um basically it's a way to find the chemical makeup of rocks using an X-ray. They've got a little beam of X-rays that goes in, figures out what comes out, so they've got a detector, and then that tells you what's in it. >> Yeah, what's in it. And then they also have this thing called SHERLOC, Yes. >> which is Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals. I think they started with the acronym. Yeah. And they're like, "Okay, how do we How do we How do we make it fit?" They do this all the time. It's so funny. Um cuz I don't think chemicals has It's SHERLOC without a K. Yeah, yeah, yeah. It's with SHERLOC with a C.

19:46Yeah. Um but the SHERLOC is it does Raman spectroscopy and it's basically a carbon detector. Mhm. In some sense. So, they used the carbon detector to find like carbon on the substrate, and then they used the pixel instrument to do x-rays on these little tiny poppy seeds and leopard spots to find that okay, it's iron and sulfur and phosphorus. And the thing is, I want to just reiterate, there are smart people who thought about this on the front end and had a plan in order to be able to like like what is the methodology by which you even like ascertain that life was there and not there, etc. Very Okay. Yeah, it's really cool that

20:27like they could fit all of this on this giant SUV, pack it into the top of a rocket, have it survive lift off, Yep. >> have it survive landing on Mars, and then now it's like actually giving us all this crazy data. Right. Right. And this thing this data is like a year old. So, they've been they've been going through it because obviously they know this is like a big deal. >> Right. Right. Right. I remember is I believe uh administrator Duffy as part of his speech in the press conference today made an emphasis on this point. He's like, "We found it last year, and we sent it all over the world because we wanted to be sure." And everyone looked at it, and everyone checked it, and they

21:08got back to us, and they were like, "You might be right." Well, so to that point, um whenever something like this comes out, this is a big this is a big deal, right? >> The great things about Nature um is that they make their peer review process completely public. >> Yeah, Nature, the publication, >> Yeah. not Nature >> Not Nature Nature, Nature the Springer publication that's been around that has published all the big papers over the past 100 years. Um very recently, they they didn't used to do this all the time, but very recently they've made their entire peer review process public. So, after something gets published, >> Yeah. Yeah. um you can go to the website, and you can go to the peer

21:48review file, >> Mhm. and see what the reviewers said. >> Mhm. And um you know, it's it's pretty cool because, you know, science should be open. Yes. And just like every grad student knows in there there's always one reviewer. Okay? For me it was For me it was reviewer one. For these guys, it's also reviewer number one. >> Of course. >> Okay? Cuz they're they're um they're anonymous. Yeah. Yeah. So, if you're anonymous, you can just start saying the most out of pocket >> heinous out of pocket things about about the work. And this guy did not hold back. Reviewer two and reviewer three were pretty nice. They were like, you know, you should you should include some of these sources. You should maybe

22:28word things different differently. Reviewer one was straight-up like, "This needs to be rejected." He said that multiple times in his first review. And he's like, "The language is bad. First of all, okay, so First of all, He He was like, "First of all, the title." He He goes after the title. He's like, "I can't believe you put biosignatures on the title." You look now, the title of the paper does not have biosignatures. So, reviewer one won that battle. >> you reviewer one won that battle because they were like, "Okay, fine, we'll take out biosignatures out of the title." Cuz he's like, "This is only, you know, you can't say that the null hypothesis, which is, you know, that this is of abiotic origin." Which it totally could be, right? These These This chemistry

23:09could have formed We don't know what the chemistry was like 3.5 billion years ago on Mars, right? So, it's totally possible that this chemistry could have formed abiotically, right? Um And so, that that that was his first qualm. Um his second qualm was about, well, like, you know, they have this analysis where they're looking at using the pixel instrument, they're looking at the composition of these nodules and things like that. And he's like, "Well, you don't have any clean data, right? Because like it's it's like you have like iron and sulfur, and you're claiming that these are the things that are in it, but there's also all sorts of other stuff, right?" And um you can look at the rebuttals that the authors uh put back. Yeah. Yeah. >> And so, the authors put back the

23:50rebuttal being like, "No, the beam of the instrument is as big as the nodules if not bigger. So, like you I can't focus Mhm. harder than I already have." >> Right. Right. Right? This thing is on It's not like I can remove a lens and put another one in. >> Right. Okay? >> Right. So, okay, so it's like this is the best data you're going to get. Okay, so that's that one's fine. Um And it also he he was also like the language, "I can't believe you're calling it poppy seeds and leopard spots. You should be calling it by the scientific terminology because otherwise people are going to get confused." And so, they took that out, and they started like referring to these things by their scientific thing, which is authigenic nodules and reaction reaction

24:33fronts. Okay? But but they also in their rebuttal, they're like, "People do this all the time." >> Yeah. Yeah. Like we've heard of Scooby-Doo spots. Right? Like like people it's not like a something that we made up. Like it's just it's just a nomenclature. Okay? His main qualm Okay. was basically like, "You guys are like hyping yourselves up way too much, okay? Like I can't believe you're saying it's a biosignature." And then he brings up what happened in 1996 Okay. >> with McKay and the paper in Science, okay? So, >> this is an incredible story because So, um 1980s, a team finds a meteorite in Antarctica.

25:16Okay. Okay? In the ice in Antarctica. >> That's where the aliens are. That's what they say. >> That's where the aliens are. Turns out this guy definitely thought so, too, McKay, right? And his colleagues. So, this meteorite is discovered in Antarctica. Yes. And then um we because it's on Earth, we can now actually put it under a scanning tunneling microscope and things like that, and we can start looking, and there's these really weird bacteria-looking things, okay? Like they it looks like one of those rod bacteria on this meteorite and things like that. And so, lo and behold, he's like, "This is life, right?" And looked like life. Honestly, look at the photos, I'd be like, "Oh, that's that's a bacteria in a scanning tunneling

25:56microscope." If you told me that it was from a Mars meteorite, I'd be like, "Okay. I don't know anymore, right?" Because if you tell me it's from a Mars meteorite, the the the burden of proof has suddenly gone up to here, okay? Um if it's just a rock on Earth, then yeah, there's bacteria on it. Um So, he publishes this thing in Science. It's a huge deal, okay? Bill Clinton gets in the White House lawn >> Right. and uh calls a press conference, >> Yes. and he's like, you know, "I did not have He was like He was like, you know, "We found We found We found uh life on Mars, and it's great." That's my best uh Bill Clinton impression. The only thing I can do really is the Monica Lewinsky thing,

26:37but I'm trying to But anyways, so it turns out that probably >> Right. not, right? >> Uh just not enough evidence to say that this thing is Right. >> is um something from Mars. But it became a huge part of the zeitgeist at the time because Bill Clinton was also announcing the Human Genome Project. There were all these big wins for American science, and this was going to be one of them. Um Dan Brown, the author of Angels & Demons, he he wrote a book Yeah, he wrote a book called Deception Point where the main Yeah, it's a great book, and it's the the main the crux of the story is that somebody finds fossilized aliens in like an

27:18iceberg right? >> So, it becomes it becomes like this huge pop culture thing. Um And what this reviewer one is saying, he's like, "You guys are repeating the mistakes of the past, right? Because the field of astrobiology has already been hurt by um this sort of fake hype, >> Mhm. and you guys are quote the new data set is quote much weaker and much less detailed than even what that guy put out in 1996." >> words. Dude, this guy was relentless. >> fighting words. >> Yeah, so so, reviewer two and reviewer three like reasonable comments. Reviewer one is just going ham. Basically,

27:59several times he's telling Nature not to publish, okay? Right. Um The The authors come back, and they say, "Okay, fine, we refined the language. We're not saying it's We never said it's biosignature. We said it's potential biosignature, which is something that even NASA agrees in in the in the greater astrobiology community agrees is what this thing should be called because certainly it is a potential biosignature. This is something phosphate and sulfur in iron next to organic compounds. Mhm. Certainly something that requires further investigation, and that's what a potential biosignature is. Um Well, I just thought of it was I was reading the the review, and it was just like almost personal.

28:42This is This is great. And so, we we we are still in a place because now that we have the understanding of what are we actually talking about because a lot of times with these stories of anything related to biosignatures, life off Earth, yeah, the news headlines number one, don't map onto the words in the paper that they cover. >> Yeah. Yeah. Because they're going for clicks. >> Yeah. And biosignature is like an amorphous word to 99.9% of everyday people. >> Yeah. What does that even mean? But this was actually helpful cuz now in this case, specifically to this research path, we understand what we're trying to say

29:24or look for when we say potential biosignature. >> it's a potential biosignature. It requires further um you know, scrutiny Yes. and further lab results. Yes. And so, actually um what the Perseverance rover did and what it's capable of doing is actually saving samples. >> Yep. So, it took a sample out of this guy, saved it, and then, you know, in the future, if we get our funding back, we're going to send stuff there, and pick up the sample. >> pick it up, and then take it back to Earth. So, I think what this means is if we want confirmation that our neighbor, the red planet, remember we're code red today, uh does in fact not just have potential evidence

30:06of biosignatures, but it is in fact biosignatures, we got to go get it. Yeah. In order to go get it, we have to fund the programs that are getting us so close to better understanding our place in the universe. And that what we think of as life is potentially Yeah. way more abundant than we thought. Yeah. But we have to spend the money. >> Yeah, we got to spend the money. And the thing is, I think like SpaceX and Blue Origin are in talks, or at least they were before the massive spending cuts. They were in talks to like try to design a mission Right. to do exactly this. Right. Right? And this is a good point. Private aerospace has risen in its in

30:48its power and its efficacy over last, let's say, 10, 15 years, particularly driven by SpaceX with Blue Origin as a close second. Um where do they get some, if not a a majority portion of their capital to even do those things? Where do they shoot their stuff off from? All government-funded. >> Yeah. All government-funded. >> Yeah. The What are they shooting? It's government-funded stuff. >> Yeah. It's not all Starlink satellites. >> astronauts up, right? The government is paying SpaceX to build a capsule to be able to put humans in. Yeah, I mean, and it's following it's following what the American model for

31:29innovation has been for the longest time, which is right, which is the government spends the money to do all the hard work. >> Right. And then once they figured out all of the little details, now the private sector can come in and be like, "Oh, okay, I can now I can now do that, and I can do it cheap, and I can do it well." Right? That's the same thing that happened with silicon transistors, right? The government was gave a blank check during the Apollo missions to a small small company in Silicon Valley that used to be a bunch of apple orchards and and orange groves, right? A small company, blank check, I need I need this size of computer in something like this, and it I need it to not overheat. >> Mhm. And blank check, do it. I just need

32:10it. Okay, we got to beat the Russians. They do it. They're like, "Well, now I can make computers." Yes. Out comes Fairchild Semiconductor, out comes Intel, out comes all of the Silicon Valley tech. >> Yes. Right? So, it's a model that's that's followed, but again, it needs like you still need the government to have that money and have that funding to jump-start these things. >> 100% This is not to exclude the idea or the fact that the private industry can and has, particularly in aerospace, pushed the boundaries of innovation. >> 100% But these are not mutually exclusive ideas. >> Yeah. Yeah. Like yes, both things can be true, and both things are true, particularly as we talk about these

32:50deeper space Yeah. >> missions in particular, where there is no commercial value No. for a private aerospace company for these more, again, fundamental discoveries. >> Yeah, exactly. I mean, maybe you're trying to colonize Mars, but that's like several hundred years away. >> Yeah, and not in our lifetime. And unless we figure out the longevity issue, which we talked about in last episode, we won't be around for that. >> Yeah, I won't be around for that. So, this was the announcement today, Mhm. >> September 10th, took the internet by storm. But this is not the first time even this year that we've seen a headline with some version of the language strongest

33:31evidence yet. Yes. >> And so our second story uh is coming out of the BBC with the headline, "Scientists find {quote} strongest evidence yet of life on distant planet." This is from April 17th. That's right. So, almost an identical headline. Yeah. Different location, potential biosignatures, strongest evidence yet of life. >> Interchangeable. This In this case, for the April story, not on Mars, No. but on a very, very distant planet. >> Yeah. And this research was coming from a Cambridge team studying the atmosphere of a planet called K2-18b. Yeah. So, as a layman,

34:12I don't understand what the difference between these two things are when the article just says strongest evidence yet. Which one is stronger? Is this one stronger? Is that one stronger? Is it the strongest? >> in my opinion, I would say the NASA one is stronger. Okay? Because you can literally see the stuff. Yes. Okay? Um and at least what we see, we know we see. Right. Okay? With this one, it turns out that the paper that came out in on April 17th that was purporting to have seen the things that it sees might not have been seeing those things. So, you're saying don't trust the headlines? Yes, I'm saying definitely don't trust the headlines, and in this case, also maybe take the scientific paper with a grain

34:54of salt. There was a lot of pushback after the scientific paper came out >> Okay. >> from the from the community saying don't don't say that. So, what's interesting about this April story is, unlike the rover Perseverance being the source of the sort of discovery, {quote} {unquote}, it was the James Webb Space Telescope. >> That's right. Another NASA product. >> no tactile evidence. This thing's just looking at stuff. >> looking at stuff really, really far away. Yeah, yeah. This one's This one's honestly 120 light-years away. So, in our neighborhood. Yeah, okay. Yeah. James Webb is capable of looking, you know, towards the beginning of the Big Bang. >> the beginning. >> Yeah. So, so this thing is looking at

35:35120 light-years away. It's uh It's a star called K2-18. It was discovered by the Kepler um space observatory. Mhm. And um this is K2-18b. So, it's the second planet to have been discovered there. The star's K2-18. The planet's K2-18b. >> B. Yeah. And so, um the the planet is a little peculiar for stuff that we talk about in terms of um being potentially habitable, because it's not an Earth-like planet. It's It's a It's bigger than Earth. It's got the radius of two Earths. It's got the mass of eight. Oh. >> one of these like mini-Neptunes.

36:18Um what we call Hycean worlds. Um we we think that there is a giant ocean Mhm. on this planet. >> Okay. Like in that Interstellar scene where they went on the ocean planet and they had the giant tidal wave. >> Yeah, yeah, yeah. Except this would be a lot a lot deeper ocean. >> Mhm. Um You won't be able to stand on it. >> Yeah, you wouldn't be able to stand and stuff like that. Um it it kind of reminds me of the um planet from Dune Mhm. that was the home world of the Atreides >> Mhm. um Yes. family, you know? Like the beautiful blue planet. Uh yeah, it's kind of like that. It's a water world. Okay. Um And it's it's what we call Hycean worlds

36:58um in the astrobiology community. Okay. Right? Um And so, what they think they found is traces of a gas called dimethyl sulfide. Mhm. This is the gas that you get with like um you know, cooked cabbage? Yes. The smell? Yes. >> That's dimethyl sulfide. Also like It's a particular smell. Yeah, also like if you're brewing beer and then it goes wrong, >> Yes. there's a smell. Yes. >> That's dimethyl sulfide. >> Okay. Okay? And that's mostly just made by like phytoplankton on Earth. Okay. Okay? So, when we found that on this distant planet,

37:38phytoplankton must be there. Yeah. It's like, "Oh, dope." And honestly, if we found DMS there, and there were there was no doubt of DMS, then it's a pretty strong it's it's pretty strong evidence. It's not everything, because again, it can happen abiotically, and that's part of the story that we're going to get to. So, first let's first let's try to figure out how we would even like try to find gases on another planet. Right. Okay? Um you know, on Mars, you can like literally just like see it. Right. Right? And then with the Mars Perseverance rover, today's news, it can just go and like oh, it's like it's shooting X-rays and then Yeah, it sees it. It's right there. >> It's right there. I'm shooting an X-ray, I get the signature.

38:19>> Not 120 light-years away. >> Right. It's This thing is This thing is extremely far. So, how do we actually determine um what is in its atmosphere? >> Right, that's my first question. How do How can we even know that from like a, you know, from a sensor system? >> Yeah, from a sensor And that's And that's one of the big reasons why everyone was so excited about the James Webb Space Telescope is because it would have this capability. So, here's the idea. Um the way we find a lot of these planets is through this thing called the transit technique. Okay. Okay? What will you do is you stare at a star Mhm. for a very long time. In this case, Kepler did it for um for a month. You stare at a single patch of the sky, and you look at all the stars, and what the star's going to do is it's going to dim

39:00every once in a while for for a few hours. It's going to dim. >> And then, maybe 2 weeks later, it's going to dim again. >> Okay. And then you're going to wait 2 weeks later, and it's going to dim again. And there's going to be a rhythmic dimming. Mhm. Okay? And what's happening is you're getting an eclipse Oh. >> of the of the of the planet in front of the star. Because it's basically like if if if I'm JWST looking this way, uh the star is in the center of my field of view, >> Yeah. and the planet is orbiting around, it's eventually going to pass in between me, JWST, looking at the star, K2-18, and it's going to be whoop. And so, the dips you're talking about That's That's going to be a transit. That's the truth.

39:40why we call it a transit method of finding it. Okay. And the way that this thing dips is called a transit curve. Okay. Right? You're going to see the brightness because these stars are stars are so far away and they're so small for how far away they are that they're basically points of light. You can't really um resolve a circle. Right. >> Okay? You just resolve a tiny point of light and all you can tell is its brightness. Okay. Okay? And so, the brightness goes down and then it goes back up. And then it's this rhythmic pattern that tells you that there's something orbiting that star >> Right. that's happening every, you know, 2 weeks to a month or whatever and has some cadence. And then you can be very sure that there that that's a planet that I'm looking at. Okay? Yeah.

40:22The the nice thing about the transit method is, okay, so you're getting a transit curve for the light, right? The light is dimming. But if you have a spectrograph, which is what the James Webb Space Telescope has, it's got a really nice spectrograph, okay? Especially in the infrared region. Mhm. Which is um where a lot of gases do quantum stuff. >> stuff. Okay? So, >> if you've got this spectrograph, what you can do is you can get a transit curve for every color. Okay. And the trick is that if there is an atmosphere with stuff in it, then the transit curve for

41:02different colors is going to be different. >> to have a different wavelength. >> Right? Because if suppose there's a bunch of oxygen on this planet, there's going to be a certain wavelength of light that oxygen really likes and it's going to absorb a lot of. So, what you're going to see is a transit curve for every for every um you're going to see a dip Yes. >> in every single wavelength, but there's going to be one wavelength that you're going to see an even bigger dip because the atmosphere is going to be taking out more of that star >> Yes. light. Yes. Right? >> Yes. That is fundamentally how we use transit method Yes. >> to find atmospheres on these planets.

41:42>> The the com- the chemical composition of the of the atmosphere. >> Yeah, the chemical composition becomes a kind of barcode across wavelength. >> Because the idea is as the light's passing through the atmosphere of the planet on its way to JWST, the atmosphere, if it has certain stuff, is going to absorb that light. So, that's what causes on the transit curve, the dip to be lower than everything else because there's a high abundance of that particular Exactly. >> substance. Like for example, suppose we had a spectrometer in the UV range. I don't think the James Webb Space Telescope does, but for sake of argument, suppose there's a alien world out there, right? And it's got a telescope pointed at us and they're just

42:23lucky enough that the Earth is transiting. They got to wait a whole year >> Years to wait for it to come back for it to come back around, but let's just say they're super patient. >> Yes. Um when the Earth goes in front of that star, they're going to see a giant dip in the UV because there's a bunch of ozone. Right? And the ozone is what keeps us from having skin cancer. Right. Right? But that's fundamentally because it's shielding us from all of this UV radiation. That alien planet, when it's watching the Earth go in front, it's going to see the rest of the light go down because the Earth is blocking it, but the ozone is just going to be completely obliterated. >> Right. Right. Right? >> Because it's so present in the atmosphere. >> it's so it's so present, right? And so,

43:05from that they can then be like, oh, this planet has a lot of ozone. Similarly, that's what we can do with these planets. >> So, that that's how we can understand the atmospheric makeup, which then from that we can draw conclusions from. >> So, so that's what these guys did, right? They they they they got this transit Mhm. from the JWST and then what they want to do is they want to try to figure out >> what kind of atmosphere would give me that barcode where this wavelength is a little lower, this wavelength is fine, this wavelength is a little lower, so on and so forth. >> Right. Right? Um to do that, now we have to use something like a probabilistic model, this thing called like Bayesian analysis.

43:45Um it's called atmospheric retrieval because we're trying to retrieve the possible atmosphere that created this signature. This this this this this is like like a barcode. >> Yeah. Yeah. So, so what you do is you simulate a bunch of different atmospheres >> Mhm. with a bunch of different density profiles, temperature profiles, pressure profiles, heights, so on and so forth, where the the the gas is, on what part of the atmosphere. And then you simulate what that would look like on a planet with that particular star because we know what the star looks like, right? >> Right. We have the spectrum of the star when the when the planet is not in the way. So, we know exactly >> that we then subtract this candidate

44:25atmosphere one one by one, right? >> Yes. And you you create this Bayesian model >> Yes. >> of all the possible scenarios >> Yes. and you try to see what model fits best fits the barcode we see in real life. >> this barcode that we see in real life, right? And so, um this team out of Cambridge from Nikku Madhusudhan, he >> fit a bunch of different atmospheres and he found that the atmosphere that had um DMS and DMDS, which is dimethyl disulfide. So, dimethyl sulfide is just um CH3 two of these with a sulfur in the middle and then the dimethyl disulfide is two sulfurs with CH3 CH3. Okay? Um And what he found was that the best model that fit it was

45:05something that had a bunch of DMS and 1,000% more DMDS than we find on Earth. And both of these compounds are very much of biotic origin on Earth. Okay? So, he publishes this thing and immediately the BBC you know, they love tooting UK's horn. So, they're like, oh, strongest evidence yet. We did it. >> Right? We did it. >> Even though it was with our stuff. Yeah. Yeah. Yeah, exactly. Yeah, like I'd like you try to I'd like to see you try and make a JWST. Anyways so here's the deal though. You read the paper Okay. and the significance level that these guys are saying is at three point three sigma. Okay? Three standard

45:46deviations. Meaning the null hypothesis is there's no DMS and DMDS. This um barcode that we saw is a fluke. >> Mhm. Okay? And this thing is saying that with about 99.7% certainty, three sigma meaning you've got this Gaussian distribution of all the possible things that it can be and we're three standard deviations away from that null hypothesis. Okay? So, we're at we're 99.7% certainty. Might seem like a lot. I mean, if I got a 99.7 with the grade deflation we had at Princeton, I'd be pretty happy. Yeah. Yeah. Yeah. Now, you don't even need grade deflation at that point, right? >> Right. Nowadays, that's uh that's an A++++++.

46:27Um Actually, back then that WAS A B-. BUT um so, 99.7% certainty seems like quite a bit. In science In science, especially in physics, and in astrophysics, that is not a lot. The gold standard is um five sigma, Okay. which is 99.9999%. Okay. Okay? Um Five sigma is the gold standard for things like the Higgs boson. I mean, if we had three sig- if if three sigma was the bar for announcing a discovery, we would have discovered the Higgs boson before CERN. before CERN. >> Yeah. >> Because Fermi Lab was doing these experiments already Right. and we were

47:09seeing the signature Yeah. of the Higgs boson, but we didn't do it because we didn't have the five sigma >> the five sigma level Right. to like actually announce it. >> Yes. So, this isn't good practice to announce something at three sigma. So, so there there is a bar There's a bar. So, that's sort of like that's mutually agreed upon that's like >> by by everyone in the community. You don't publish Yeah. unless you reach this bar. Mhm. But then these guys did it at three sigma. >> It's funny cuz I'm looking at this quote in the BBC article from the lead researcher um who who said, "This is the strongest evidence yet there is possibly life out there. I can realistically say that we

47:49can confirm this signal within 1 to 2 years." >> Okay. So, he's saying that we can confirm the signal. But then why are you publishing it? >> That's the that's the kind of point. >> the other the other thing is like a year before that, a year before like in 2024, I believe, >> Yeah. Yeah. it there was a thing that came out in the BBC that like it's a tantalizing signs of possible life on a faraway world. Okay? >> And that was at one sigma, 66%. >> Yeah, I know. At 66%, I can't believe you're even talking to the BBC. >> And okay, here's here's the funny part. That BBC article is written by the same guy who wrote this.

48:29So, I'm not saying >> what you think I'm saying, but I'm saying that maybe these two guys are like friends. Okay? And and like they had dinner and he's and he said, "Hey, I got Like dude, at one sigma I've I I In science at one sigma, you talk to your lab mates about how to improve the sigma. >> Okay? You maybe talk to like close collaborators. You don't talk to the media at one sigma. That's insane to me. 66% >> Yeah, 66% dude, like that's that's like a bad coin. Yeah. Right? You bri- right right right. Like that's so close to In Okay, anyways. But

49:11I get it. Understandably, 17th of April, this this paper comes out. Understandably, there's a lot of backlash from the community. >> lot of reviewer number ones. Yeah. Yeah. A lot of a lot of like So, a week later, um this guy Jake Taylor from Oxford, a week later. So, Oxford Oxford and Cambridge, they've always had beef. >> Yeah. >> This guy comes out and he's like, "Actually, with five sigma, I'm telling you um well, actually like so he did six different other models with the same data. This is the model of the potential atmospheres that could match to the barcode. So the idea is Cambridge said we looked at a bunch of possible barcodes. We found one

49:52that's a really close match. Yeah. Now Oxford came back Oxford came back and it's like well I did like six different methods of doing this. And only one of them showed DMS. But five of them don't. >> Mhm. So what are you talking about? >> are you talking about, right? Five of these fits don't have any DMS but they're fitting with this guy pretty pretty nice. The accuracy is kind of like you cherry picked one. Yeah. And you didn't really didn't do >> Like an exhaustive search, right? And that was that was a week after this this guy published, right? He's a post doc he was just like no. >> About a week ago a week is crazy. >> right? And then and then about three weeks later the Americans start coming out, and cuz we we wanted a little more time.

50:33So the Wellbanks group at the University of Arizona, they show pretty conclusively that like propyne which is C3H4 abiotic can also produce the same signature, okay? So it's like well you have you you had like certain constraints on your atmosphere retrieval but now like once we expand the search there's all these other molecules that sort of fit the bill. University of Chicago does the same thing with all the data and they're like I don't I don't see it. So everybody was like >> like bro what are you doing? And then actually I looked up the most recent one is the 18th of July 2025. UCLA, Caltech, and actually Nikku Madhusudhan who's the original

51:13lead author of the April 17th paper, he's also a co-author in this. Okay. And they say that there's probably water on this thing like a liquid ocean. Given that given the um the levels of ammonia and nitrogen and methane that we see like that level suggests that there's liquid ocean. But he also like pulled back on the DMS. >> to say that's a TOTALLY DIFFERENT ARGUMENT. SO SO HE'S LIKE HE'S LIKE THERE'S this and then and then like and then like the one little sentence of the abstract is like but the DMS could have been could have been made abiotically actually. So maybe the BBC article needs a slight

51:54correction. >> Yeah. They really should like put out a little you know disclaimer. Because Like or a little asterisk at the bottom being like >> the UK always runs to the Americans. Yeah. You need the help. >> Yeah. >> so it's so they they've sort of been a pivot Yeah. in the in the claim which is like oh it's probably a liquid planet. >> Yeah. Okay. Okay. But the DMS stuff let's let's let's So the evidence was not the strongest. >> No. No. So that's a great way to distinguish when you see headlines and it's like tantalizing strongest potential evidence of life

52:34what is it evidence of what what type of life is it microbial life is it intelligent life is it a biosignature is it a technosignature there's all these >> Yeah is it a potential biosignature or is And so with with the rover Mars the reason why Mars is a great laboratory or great research ring is because we can touch and feel and look it's right there. >> It's right there, yeah. And we can bring it back. >> bring it back if we fund Yeah. the trip back which we should cuz we want to know that there's aliens out there. But this is a very this is a very good contrast because you know as many viewers know and I know you know like I work in at a nonprofit that's sort of addressing

53:16this unidentified anomalous phenomena issue. It's funny I actually tweeted earlier today ex-posted whatever people want to say. Yesterday Yeah. was this UFO hearing in Congress. Yeah I heard about that. >> Oversight Committee. And there was like that crazy video. And there's a crazy >> Yeah that that like crazy I was like I don't know about this. >> crazy video of a Hellfire missile being fired at this object flying over the ocean. It makes contact but it does nothing to the flight path of the thing that is flying. Mind you like Hellfire missiles are one of our most sophisticated advanced like it it it's a problem if it's prosaic or

53:57not or anomalous it's a problem regardless. But the the juxtaposition or the sort of fast follow of like that hearing happening and then I woke up and then NASA was like oh wait we might have found life on Mars. It's like what are you hiding? No I'm kidding. Yeah and and like understandably like this kind of research and and this kind of claim requires an extraordinary amount of evidence because this would be one of the biggest discoveries in human history. Finding out that life exists elsewhere elsewhere is it's I mean it's in the top three. Yeah it's in the top three. You can argue about whether it's LeBron or Michael Jordan is the goat. >> Yeah but like it's up there. It's either Kobe LeBron or Jordan. Right right right it's so it's kind of like

54:38that situation. >> can all agree that this is going to be a huge deal if it if it comes out which is why there's so much scrutiny every time somebody says something, right? And which is why I think reviewer one on that last paper was so pissed off. >> went ham Right. went absolutely ham. So this is so okay. So this is good cuz we're going to go to the last story which kind of creates a nice bookend for all the fans of the new TV show on Apple TV the studio. We need a nice bookend. Love a good bookend. And so the last story is out of both Scientific American and CBS News. This is also sort of like a brand new breaking story which is again another word hints of atmosphere

55:19on Earth-size exoplanets raises hopes for life in a new another James Webb Space Telescope finding. Yep. What's interesting about this one is like Halo they came out guns blazing dual wielding research papers. Yeah. So that wasn't one it was two in the Astrophysical Journal Letters related to this hints of atmosphere. So it's sort of great that we just talked through the transit method and understanding like how like how do with JWST like detect the atmosphere from using sensor technology. >> Exactly, yeah. So we have that grounding. >> have that grounding now and now we are looking so this this came out September 8th. Very recent.

56:00>> This was two days ago. Everyone's excited about this because this is a paper on the TRAPPIST TRAPPIST-1. TRAPPIST-1. Have you heard about this? So TRAPPIST has been again because I did the UAP stuff that's where the that's where the aliens That's where the aliens are. Everyone's like that's where the aliens are, right? TRAPPIST-1 is is a great little micro lab for solar system research, okay? The reason for it is um it's it's got a bunch of rocky planets that are all transiting. in front of like we just talked about the Right? The the problem with like finding planets is it's incredibly hard to

56:40detect, right? Think about like I mean think about think about how we find the planets, right? You were saying that you got to look at this thing. Yes. You got to look at the star and you got to look for the star's brightness to dim. >> Yes. And then you got to wait for it to dim again. And then you have two and you got to wait for that third because then you know that it's rhythmic, right? If it's just two it could just be two random things going in front or whatever and then you know. So you you have to wait for that. Yes. The other thing is you got to get lucky, right? The the solar system has to be on edge to our field of view. If you've got a star over here and the solar system is doing this >> it won't pass in front. >> never going to pass in front and I'm never going to see it. Right. >> Right? And so the solar system has to

57:21have that exact angle of being like in our line of sight. Right? Can't be up here like angled >> got to be incredibly lucky. This thing is not only on edge, right? It's got like a bunch of planets Yes. >> that are all on edge that are that are doing this transiting. >> Yes. Also the transits are very very short. From one and a half days to 19 days. >> This goes back to what we were talking about earlier if there was an alien species looking at Earth our transit time is a year. >> A year. They they'd have to keep staring at the sun. They'd probably see Mercury. And and and then they'd be like oh there's no there's no atmosphere on this thing. >> Right and then give up. >> And then give up, right? But then they maybe they'd see Venus and they'd be

58:02like that's got a hell of an atmosphere. You know. Right. >> But like yeah Earth they'd have to wait 365 days. >> Just for once and then they'd have to wait two more years to get the three. >> more years to get all three. >> fact that the transit is just a couple of days >> Couple of days to like 20 days. is huge cuz it's cuz it's this is a resource allocation issue. If we had a bunch of these tools Yeah. >> we could just point wherever or leave them forever it doesn't matter. But there's limited time and everyone wants to look at different things for different reasons. And so that's a really good point that the transit time is so short. >> is so short which is mean and meaningful variable. >> Yeah and the other the other great thing is so TRAPPIST has a bunch of these planets, right? So imagine you've got a star like this and you've got a bunch of

58:42planets, right? Now where the habitable zone is is kind of nebulous, right? It's like we don't know exactly the there's no like hard line of that Goldilocks zone. But because we've got all of these in a line even if the habitable zone is here there's going to be a few planets in there. Even if the habitable zone is out here there's going to be a few planets in there. So it's like hedging our bets on all of these planets. Right? That's why TRAPPIST-1 is very exciting to us. It was it was found by the TRAPPIST system which is this transitory planetary project in La Silla Chile. Really quite small telescopes to be

59:22honest that are just doing this thing where they just stare at a bunch of stars and then try to do photometry on them to figure out brightness. Yep. um it found this thing, I think in like um 2016. And ever since it's been it's been it's been a big part of the um exoplanet research community. >> research community. Um so, a bunch of planets have been found. As we've looked at it for longer and longer, we know that some of these inner planets do not have an atmosphere. Okay? Um it makes sense because this solar system is extremely small. >> It's a conden- it's >> It's condensed. The the star itself is an M dwarf. The the classification of

1:00:02stars goes OBAFGKM. We are a G-type star, the sun. Yep. Um M is all the way on the right-hand side of the Hertzsprung-Russell diagram. It's tiny. It's red. It's tiny. Okay? Um and so, th- this entire planetary system is condensed in st- inside of the orbit of Mercury. Oh, wow. Wow. So, the distance between our sun and Mercury Yeah. All these planets >> are in that >> are inside there. Okay? Now, that's a good thing because if you've got a really dim star, you want to be close to it in order to like have like with water and all this other kind of stuff. On the other hand, if you're that close to a star, the star's going to act up.

1:00:43>> Right. Right? There's going to be solar flares. It's going to be random like it's going to like vomit. >> Yes. >> And then and then you just get a giant dose of radiation. Right? So, that's probably why the the inner planets don't have an atmosphere anymore because like okay, like you're close to the star. Like even though the star is like small, it's still going to be volatile. It's still going to have all these like little outbursts. And so, and so, you're kind of screwed there. But, the TRAPPIST-1e, which is E is the planet now. This is I believe the fourth planet that's out there. Um that's something that is kind of Earth-like. Yes. >> Okay? It's about um 90% the radius of the Earth. So, about 60% the mass. >> Yeah, yeah. Which means it's like, you know, if we're on there, we can like at

1:01:24least like hang out. >> Yeah, yeah, yeah. Um we'd we'd be jumping a little bit higher. >> A little moon-like-ish. >> Yeah, a little moon-like-ish, but it's it's not like something that is completely foreign to us. Right? The moon is the moon is a sixth of Earth's gravity. This is, you know, going to be like 60%. >> It's like it's like a trampoline world. Yeah. Yeah. And it's got an equilibrium temperature, they say, of about 250 Kelvin. Okay? So, it's a little bit out of the where the Earth would be to get Earth's um equilibrium temperature, which is what, around like 280 Kelvin? This is at 250 Kelvin, which is what, -20° C? That's the equilibrium temperature. Now, the thing is,

1:02:05you can have, if you've got an atmosphere, >> Mhm. like Venus, Mhm. you can have a massive greenhouse effect. Okay. >> And then that greenhouse effect can keep heat >> heat >> in in. And if you have a massive greenhouse effect, the pressure is also higher. So, then you can have liquid water. Right? So, there's a possibility that we could have liquid water on this thing. And we could have types of um habitable-like qualities on this thing. Right? So, so, trying to trying to figure this out is is is uh is a big problem. Okay? The other cool thing about um all of these planets are because they're so close to the to their sun Yes. >> right? Um they're within the the within

1:02:46the orbit of Mercury. Yes. Right? They do this thing called tidal locking, which is something that the Mercury does to the sun and something that the moon does to the Earth. >> Yes. Whenever we look at the moon, we see the same face of the moon. And that's because as it rotates, it's also rotating Yes. >> itself. >> Yes. Right? And the rate of rotation matches >> is matching the rate at which it rotates the Earth. >> Yeah, yeah. Right? The Earth doesn't do that, right? The Earth spins once every 24 hours, >> Yeah, yeah. once a day, Yeah. and then it takes 365 days to go all the way around. That's why we have 365 days. A day on the moon is also a year on the moon if the Earth is like kind of its center. You know what I mean? >> what you A day on Mercury is also a year

1:03:28on Mercury. >> Right? >> Yeah. All of these planets, because they're so close to the sun, are tidally >> have this tidal locking, right? Which means they also always face their sun. The the the point is there's one side of the rock is always in the sun. And the other side is always in the dark. This is why people say the dark side of the moon. We never see the dark side of the moon. The Chinese can cuz they landed something and they're over there and we don't know what they're doing and the national security state is freaking out about this. >> Yeah, it's freaking out. Yeah. But but that that's as as like that's >> that's the idea. >> That's the idea. Yeah. So, like you know, um that actually causes some problems for like cuz the Earth has this dynamic climate.

1:04:08>> Mhm. A lot of it is because we've got all parts of the the the Earth getting some sunlight, right? Now, imagine like you've got you've got something like this. What kind of world would that be? Um and I was reading about this. It's really cool. They call it the staring eyeball planet. >> Okay. >> Okay? So, what's happening is you've got one part of the the the planet looking at the sun, right? >> Yes. If this thing is really cold, then okay, fine. The dark side is just going to be frozen. >> But, the part that's looking at the sun, there's going to be a central part >> Yeah. that is sort of hot >> Yeah, yeah, yeah. and like maybe has liquid water if it has water. And then as you go towards the the outer parts, you're going to have this these this middle region where it's like freezing.

1:04:48>> Yeah, yeah, yeah. And so, you're going to have this eyeball Yeah, yeah, yeah. staring at that sun the whole time, right? Where the central part that is that is where the sun is always overhead all the time, >> Yes. that's going to be the part that's going to be where Where you want to >> there's going to be this temperate zone, right? Where we would want to live if we ever went there. Yep. Um which is kind of cool to think about. Like a planet that looks like a staring eyeball. >> Yeah, yeah, yeah. Um Yeah, yeah. Anyways, so, they're trying to find the atmosphere on this thing. Right. Okay? So, you want to do the same thing that you did with the K2-18b. >> Yes. Right? You want to look at this thing. You want to look at the star on its own. Then you want to look at the the planet transiting it. And you want to see which wavelengths does the atmosphere, if it has one,

1:05:29absorb. >> Mhm. Okay? If it had no atmosphere, every single wavelength would be absorbed at exactly the same amount and you would just have a flat line. No barcode right? >> No barcode, just um flat absorption across the spectrum. >> Right. It it to take the bar- just to like really emphasize the barcode analogy, it would it would be like just having a barcode where all the bars are exactly the same. Like some barcodes like have a little like pattern and this and that. But, it would just be like no. >> It would just be black. >> Yes, yeah, black. There would be no >> no white black markings, right? >> Right. Yeah. So, it would just there would be That's the that's the no atmosphere barcode. >> Yeah, that's the no atmosphere barcode. Okay. So, um they they get data from four transits cuz again, this thing, you know, 20

1:06:10days. >> yeah. It took a quick we're like, all right, let's just stare at it. >> Right. Um they they get this thing for um four different transits. And what you want to do is you want to average them out so that you get like higher signal-to-noise. Mhm. Right? You you um and it was weird. Okay. Because the first two times, the transits look way different than the next two times. Mhm. Okay? And that's very strange. It would it be especially strange like because it's tidally locked, that would mean we would get in theory some more semblance of consistency. >> Yeah, yeah, cuz you're getting that same slice right? >> time. >> every time. And you're thinking that

1:06:50there's not a lot of circulation because this thing is so tidally locked, right? Um Right. >> like the the thing isn't like revolving underneath where where there's like mixing and stuff going on. Right. Um so, you would expect that the atmosphere Right. >> the atmospheric signature >> Right. >> should be static. Right. Okay? This is not. So, what's happening here? And it turns out that the star itself is pretty volatile. Okay. Okay? And so, when it's like if the star has, let's say, like a sunspot on it >> Yeah. at some point. >> Yeah. And then I do a transit versus when the star is just like a normal star. Doesn't have a flare. Uh yeah. Then you're going to get these different the the the initial background

1:07:32radiation has signatures >> that then are getting confounded by the thing in front, right? And that's why this thing required two papers. I see. Okay. >> So, the first paper, which is by Espinoza and the colleagues, um that one was trying to mitigate something called stellar contamination. Okay? That's the idea of Okay, how do we model the starlight Right. and try to get a clean spectrum It's it's basically we want to remove the the star's radiation effects. Like how do we get rid of that noise to get just the planet's atmosphere >> Just yeah. barcode. And so, that was um the Espinoza paper. Then there's the uh

1:08:15Glidden paper. And that one does a detailed analysis of the spectrum that comes out of the Espinoza paper. Uh so so so okay, so someone created a model to get rid of the radiation. >> paper. Yeah, yeah. And then there's a there's a paper about Okay, now that we now that the tech- cuz the technique like already like the you know, to do this Yeah, yeah. required so much stuff that they're like, this needs to be its own thing. >> Yeah, yeah, yeah, yeah. I need a first author on this. All right. >> I love I love research. >> put get make me a minor author on the other one, but this one, I got a career TO THINK ABOUT. SO, BUT IT IT'S a it's a really cool it's a really cool way of doing things. They did this again, it's a probabilistic framework. They did this

1:08:55thing called um Gaussian processes. Mhm. Which is basically like it's a probabilistic solution where what you're doing is you're like varying all these functions on all the things that the stars could be and like what you're seeing and then you try to match. And then you try to get like a sort of single combined decontaminated transmission spectrum >> Right, right. >> out, right? Of that TRAPPIST-1e. So, the idea is we were originally just getting a this like initial barcode that included the contamination >> Yeah, from the star just doing weird stuff. So now we have like a remixed barcode. Yeah, to try to get that static atmosphere out. Just the atmosphere. Out of those four transits. So if it's like

1:09:36we wanted a we wanted a you know it's like a rap song. It's like no features. Yeah. This is J. Cole album. Yeah. Yeah. J. Cole, no no features. >> No features. Exactly. But you're giving me Yeah. We got we got we got Young Thug. We got Drake. We got all these other people here and I just want J. Cole. I just want J. Cole. So once they got J. Cole then the J. Cole went to the Glidden team and then they're the ones who are like, "Okay, this is what J. Cole's like." Yeah. Right. Right. Right. Right. Right. Right. Right. Okay. Yep. Okay. Yeah. So so the Glidden team then gets this atmosphere out which is this decontaminated spectrum and from that they do some analysis. So again they're going to do the same thing where they have this atmospheric evasion retrieval where they're going to try and fit all these atmospheres. One of the other cool things they did was actually one of them

1:10:17is this model agnostic. So before even involving the model and like trying to fit like all these different models, they just did like a a fundamental physics type of thing which is like let's try to figure out how big the molecules are. Okay. In atomic units. Atomic units are basically like one proton, one neutron, okay? So like hydrogen would have a molecular weight of two. Mhm. Because there's one proton, one proton, H2, right? Oxygen would have a molecular weight of 32. Because it's 16 and 16. Eight protons, eight neutrons, eight protons, eight neutrons to make the O2 molecule. Mhm. CO2 would be even more. That would be 32 plus 12 which is 44.

1:11:0144 right? So you one can figure out the molecular weight >> Yes. of that atmosphere by modeling the height of the atmosphere, okay? Because if the dominant gas, let's say the dominant gas is of some molecular weight um the higher the molecular weight, the lower the atmosphere is going to be because it's heavier, right? Also we know the temperature, right? The the higher the temperature, the higher the atmosphere is going to be because there's going to be more energy for it to go Yep. higher. Also the the higher gravity is, the lower the atmosphere is. But the gravity we can kind of tell based on the density metrics to be like, "Okay, it's about you know 60% of

1:11:41Earth." Um temperature we can tell based on um it's distance from the thing. So we can say it's 250 Kelvin. Yes. And then the height we can tell by looking at the the way that this transit works. Right. Right. Right. By the way that the transit works. And so now we can fit the molecular species. And they found that the the lower bound on the molec- molecular weight is about nine molecular units. Okay. Crucially that means it can't be hydrogen. Okay. And that's huge. >> Okay. Okay? If it's night if it's not a hydrogen dominated atmosphere that's a very good thing because that means you've got higher pressures. Mhm. >> greenhouse effects going on,

1:12:22>> Right. right? And you've already just from fundamental physics ruled out that there's probably not hydrogen there. So it's not like one of these Jupiters, >> Yeah. Yeah. Yeah. Yeah. Jupiter's just like all hydrogen effectively. Right. Right. >> Like a and a bunch of helium I guess. >> That's so clever. It's a nice one, right? I thought that was cool. >> No, that's really and and again it's it's sometimes I just I keep coming back to this point every time we talk about these these experimental designs is like sometimes it's just about reframing the problem set. >> Yeah. Right? It's not necessarily that you need the new shiny thing. Yeah. Sometimes you have the data and you just need to kind of come at it at a different entry point and then your follow-ons cuz now I know you're going to continue. So now

1:13:03that we know that like it it creates a different context by which you're then analyzing all the other downstream Yeah. steps in the process. >> Exactly. Yeah. Yeah. So now you can now you can start simulating atmospheres that don't have hydrogen, right? >> Right. Which removes a whole And so then you So what they did was they simulated a bunch of atmospheres. What they're figuring out is there's probably also a not not a lot of CO2. Okay. Okay? Um which means that it's not like Mars or Venus. Venus and Mars are basically all CO2. Um So this one's not like Venus or Mars. They say at this point what they're saying is it's either it's got no atmosphere and we're seeing just noise Mhm. or it's got an atmosphere, not

1:13:46hydrogen, not CO2, but perhaps a lot of nitrogen kind of like the Earth. Also kind of like Titan. Right. And it's got signatures of a lot of methane. Mhm. We don't see a lot of oxygen I don't think. Okay. Okay? Um so there's no like photosynthesis going on which kind of makes sense. I mean the star It's a very low Yeah. So dim. >> Yeah. Yeah. Yeah. Um It's not a big enough power source. Yeah. Yeah. I mean if if if it was doing photosynthesis perhaps it's doing a much different kind of photosynthesis because the spectrum of the star is so different from the sun's right? >> Sure. Um but nitrogen and methane which is kind of like Titan Mhm. which is very exciting because Titan is also a candidate for Mhm. um you know potential life. Tantalizing science.

1:14:27>> Tantalizing science, right? Yeah. And so it also gives credence to like perhaps studying Titan a bit more, right? To see if if if worlds like Titan are very common in the galaxy, then studying Titan more is going to give us more clues into how this would work, right? >> Um And Titan's closer. The point is that it's closer we can do more there and then we can extrapolate what we learn from that to them farther Exactly. Yeah. Yeah. And so that's the that's the whole idea. I mean they're they're looking forward to more transits in the future and actually what they're going to do that's kind of really cool is they're going to see what a transit on the B planet looks like because the B

1:15:07planet doesn't have any atmosphere. We know that for sure, right? And so then if if we can figure out what what a transit for B looks like and just like get a bunch of that data, then we can model the star transiting a bare rock >> Mhm. really well and then we can have an even better idea on what the transit on the E planet would look like, right? And then and then we get better data, better signal to noise, better model fitting, >> Mhm. higher confidence on whatever's out there. I love we need to do alien week like shark week on pod. >> Yeah. I just >> Every once in a while whenever there's something cool like we got to do it. >> that literally >> was cool, right? Mars was the Mars story

1:15:49is very cool. >> This week we had not only this hint of atmosphere on Earth-size exoplanets which came out two days ago on September we also had the NASA announce a totally separate, totally different context for for Mars. Um And All four stories are American. Yeah. Look Look you can't avoid us. >> avoid us, right? The Mars story is is obviously the Perseverance rover and JPL and then the other three papers all James Webb, baby. >> which again, you know, this is why we need to continue to fund science if you want aliens. We have to fund >> Yeah. the fundamental research.

1:16:30>> Yeah. Even if the aliens are looking at us right? And and we give up on science >> Yeah. Yeah. They're going to be like They're going to be like, "Ah man, they almost had us." >> had us. They almost had us. And so to do a real quick quick recap, we started off with the massive breaking news of strongest strongest evidence yet of biosignatures on Mars announced by NASA, huge press conference, all the things. We then compare that to the April story in the BBC out of Cambridge uh which had follow-on papers from Oxford University, University of Chicago um and lastly the Caltech UCLA combo about strongest evidence yet of life on a distant planet

1:17:11which we we sort of broke down why they've now pivoted to saying maybe it's a water world. >> Yeah. And we ended with another follow-up on how we are trying to understand the atmospheres on exoplanets which is on the path to basically being able to identify what targets really make sense for us to look for life. Um Very informative. Very clarifying. Um I I just I I I wish we got this kind of clarity in the articles Yeah. that most people read. Yeah. >> if you are watching this and this was super helpful, please share it with your friends >> do. who might be interested in this

1:17:52subject because again like understanding like what are we actually saying Yeah. when we say what is the evidence? Yeah. >> What is a biosignature? >> that hard to understand. >> No, it's not. Right? It's like if if you like go through it and you know like just go through step by step. It's like, "Okay, this is the data that we collected. This is why we think that data says what we think it says, >> Right. right? And these are the limitations. These are what we can do next." It's like not it's not that crazy difficult to understand the logical steps required to conclude >> things. Get to get to the conclusion. Yeah. Um We're looking for five sigma significance plus. >> Yeah. Um and I'll just do a quick

1:18:33uh housekeeping uh the just response has been unbelievable to the show. Yeah. Uh we really appreciate everyone. If you've watched all the way to this part of the show, that means you're true fan. We really appreciate you. We have we are literally one of the fastest growing science podcasts on the planet. >> Yeah, it's unbelievable to us. >> It's it's gone global. Um Just continue to add your comments, add your questions, add your clarifications. You can always find all of our episodes anywhere you like to listen to your podcast on YouTube, Spotify, Apple. We post clips all over our socials on Instagram and TikTok and Facebook and X. So you can find us where you want to. I

1:19:14as always am your host Lester Nare joined as always by one of the smartest people I know, our co-host and resident PhD, Krishna Choudhary. This is from First Principles, an amazing emergency pod. Uh, we'll be back next week for regularly scheduled programming. Appreciate you guys. Peace.