Planetary Radio: Space Exploration, Astronomy and Science - Twenty organic molecules found in an ancient Martian rock

Episode Date: May 20, 2026

NASA's Curiosity rover has been exploring Mars' Gale Crater for over a decade. A new analysis of samples collected there reveals something remarkable: more than 20 different organic molecules preserved in ancient rock, including the first detection of a nitrogen-bearing heterocycle on Mars, a type of molecule that's a precursor to compounds essential for life as we know it. While these molecules aren't evidence of life, they tell us that the chemical building blocks for life were present in ancient Martian environments. In this episode, we talk with Amy Williams, an astrobiologist and associate professor at the University of Florida, about what this discovery means for our understanding of Mars' habitability. Then, Planetary Society Chief Scientist Bruce Betts joins us for What's Up, where we compare the results to samples collected from asteroid Bennu. Discover more at: https://www.planetary.org/planetary-radio/2026-diverse-organics-gale-crater-marsSee omnystudio.com/listener for privacy information.

More than 20 organic molecules preserved in ancient Martian rock for three and a half billion years. This week on Planetary Radio. I'm Sarah Al-Ahmad of the Planetary Society, with more of the human adventure across our solar system and beyond. Today we're talking with Amy Williams, astrobiologists at the University of Florida, and longtime member of the Curiosity rover science team. We'll speak about a landmark experiment that revealed more than 20 diverse organic molecules in ancient Martian rock. rock. Then we'll check in with Bruce Betts, chief scientist of the Planetary Society for What's Up and our weekly random space fact. If you love Planetary Radio, I want to stay informed

about the latest space discoveries, make sure you hit that subscribe button on your favorite podcasting platform. By subscribing, you'll never miss an episode filled with new and awe-inspiring ways to know the cosmos and our place within it. NASA's Curiosity rover landed in Gail Crater on Mars in 2012. For more than a decade, it's been making extraordinary. discoveries about the red planet's ancient past. Today we're going to be talking about a paper that just came out. It's called Diverse Organic Molecules on Mars revealed by the first Sam-T-M-A-H experiment. This is a result that's been years in the making.

As I've said, Curiosity found more than 20 different organic molecules in a single rock sample. That includes the first detection of a nitrogen-bearing heterocycle on Mars. That's a type of molecule that serves as a building block for DNA, and other compounds that life depends on. At least, life as we know it. Joining us is Dr. Amy Williams. She's an astrobiologist and associate professor at the University of Florida. You may remember her from her appearance on planetary radio back in August of 2023. She joined us to talk about the Mars Life Explorer mission concept and the search for extant life on the red planet. Amy studies the formation and preservation of biosignatures

in extreme environments here on Earth. She uses that work to inform the search for life and habitability on other worlds, like Mars and Celadus and Europa. She's a science team member on both the Curiosity and Perseverance Rovers. And she's the lead author on this new paper, which was released on April 21st in the journal Nature Communications. Hey, Amy, welcome back. Hey, thanks so much for having me back.

I'm always down to talk about, you know, life on Mars, the detection of organics, but I have to tell you this story about how I encountered this paper because I think it's really funny. I was recently in Washington, D.C. for the Planetary Society's Day of Action. We go up there with a bunch of advocates and we talk to Congress. And I was flying out, but it occurred to me, I want to go see the Smithsonian Air and Space Museum one more time before I leave. So I was standing in line that morning and the person behind me in line, we got into a conversation. It was a woman and her husband and their two children, and she asked me if I had heard about this story. And I had been so distracted by everything going on with Artemis and our Day of Action that I hadn't caught it, but after

looking it up, the paper had literally just come out the day before. And it's wild to me that this got so much press coverage, even in a single day that a random person I just met had figured this out. So I just wanted to share that. I thought that was so cool. I am honored. And I mean, I think it speaks to like the reach of what we're doing as a community, right? That like, I mean, obviously we don't know who these folks were. Hopefully they are, you know, interested, science-minded, you know, just folks who care about what we're doing in planetary science. And so, I mean, this makes my absolute day to hear.

So thank you for sharing it. And then thanks for tracking me down to get to talk about this paper. Well, if they're listening out there, this one's for them because they taught me something. I hadn't heard about it yet. I was like, are you talking about the. the detection of potential biosignatures and the Sapphire Canyon sample. There's so much amazing Mars science that's been going on since we last spoke. Yes, absolutely.

But this is a whole new thing. So your team's paper is called diverse organic molecules on Mars, revealed by the first Sam TMAH experiment. So even in the title, there's a lot to unpack. Oh, yeah. Right? So why don't we start at the very beginning? Like, what is a TMAH experiment?

Oh, excellent. Yes. So as you know, the NASA and NASA affiliate folks like myself, we love our acronyms. So we're going to, we can break down some of these. Tm.M.A.H stands for the name of a chemical, which is tetramethyl ammonium hydroxide. So you can think of it as basically just a chemical that we are reacting with drilled samples that curiosity collects and, you know, performing an experiment that gives us new information about organics on Mars. Is it an acid or a base? Like what kind of chemical is this? It's actually very basic. It's very alkaline. It is this, you basically dissolve this salt in methanol, which is an organic solvent. And we sent 500 microliters, which when you say microliter, it doesn't sound like a lot, but it's actually a ton of this chemical in actually two of the 74 sample cups that flew on the Sam instrument on Curiosity. And so there's a decent amount of this chemical on board to perform this experiment exactly two times. And so there was a lot of, I don't want to say pressure, but we really wanted to get this right. We wanted to pick the right location and perform the experiment to get as much good data out of basically this, you know,

one or two shot experiment that we were ever going to get on Mars with this mission. See, that's what I was wondering about because, I mean, bases are pretty corrosive. And this has been up there with curiosity since it landed in 2012. The rover itself is already way past its expected kind of operational lifetime. So the fact that you're doing the experiment now, and this is the first time, made me really curious about why now? What was the timing element? Well, embarrassingly for me, I have to say that we did this experiment in 2020.

So it was eight years after we landed. And it has now been six years since we performed the experiment that the data were able to be published. So I'll say that we waited eight years to do the experiment. first because we, for a while, if you recall, the drill was not functioning nominally on board curiosity. And so the amazing engineers at JPL had to basically reconfigure how the drill functions. And so once we brought drilling back online, you know, we had all these incredible data from climbing up onto Mount Sharp. We were past the Vera Rubin Ridge, which was this iron oxide bearing sort of really like resistant layer. And then we moved into what we were calling the

clay bearing unit. And we were getting all these really exciting results from Sam about the presence of organic matter there. And we always knew we needed this experiment to be in just the right place to hopefully get as much data as possible. And so we finally got to that point in 2020. We knew enough about the clay bearing unit. We were able to pick a location to perform the experiment. And then, you know, with the results, you want to be as robust in your interpretation as possible. And so we spent a lot of time testing the different molecules that we thought that we had seen with the experiment, testing it on basically the flight spare instrument or pieces of the instrument that are on the ground here on Earth. And so just wanted to make sure that we had our identifications right.

So science takes a long time. This one took a little longer than, you know, we would have hoped. But, hey, it's out there now. We're so excited to share these results. And these are really exciting results. There's just a wealth of organic compounds that you guys detected. How many different organics did you find? So we've been generally saying more than 20, a couple of the ones that are identified.

We know our sort of background products that we would expect from the SAM instrument. You know, like you said, we've been operating on Mars for more than 13 years now. And so we are getting to the point that we need to pay attention to what's in the background, basically, of our instrument. So what kind of rock sample did you put into this? And why was that one special enough that it deserved that? kind of TMAH experiment? So we did a lot of work on the ground in the years leading up to the experiment, testing

TMAH and how it reacted with different kinds of terrestrial rocks. We wanted to get a rock that should contain a bunch of organic matter, and it turns out that minerals that form clays are the ones that are best at basically binding organic matter to their mineral surfaces. And so we wanted to find a rock that had a lot of clay in it, a muds, would have been ideal. We ended up with a sandstone with a lot of clay in it for this particular location. And we actually did this awesome sort of survey of the clay bearing unit. We ended up naming it Glenn Torridan. So we did this amazing survey of this whole unit and found certain strata

seemed to have more organics present than other strata. And so we actually, at the end of exploring the clay bearing unit, we were almost ready to actually keep moving up slope into the sulfate-bearing unit, we made a pitch to the team and said, look, we need to detour, kind of back down a ways to this particular layer in this unit. We think it's going to have the diversity of organics we're hoping for. And so we, in part lucked out, but we were also able to apply the things that we learned on the ground to pick the right area to do this. And so the rock, we ended up naming the drill target, Mary Anning, after the English paleontologists and fossil collector. I think it's really cool to have, you know, a first of its kind experiment performed on Mars and then be able to sort of name the location after really extraordinary woman in history who was really a trailblazer in paleontology.

Yeah, having Marianne near Vera Rubin on Mars. I mean, that's just cool. Oh, it's awesome. Yeah, it means a lot just, you know, on that personal as well as professional level to be able to honor some of these extraordinary women. So you found this really cool rock. You did TMAH experiments on it. How does the base release materials from this rock in a way that our classic kind of heating experiments don't? Yeah, a good way to think of this is the way the SAM instrument works is, as you're right, we take these powdered rock samples and we heat them up in our oven. And that can release the volatile materials. So the organics, it can tell us about inorganic gas phases as well. and what we're able to do is when you just heat the sample, it's sort of like taking a sledgehammer to a wall. You're getting all the parts,

which you might have bits and pieces of things, and you don't really know how it goes back together quite in the same way that you do if you do an experiment with TMAH. So TMAH is really good at breaking down more complex organic matter. It basically like cleaves it apart in predictable ways and it adds a little chemical, what we call a functional group, but just imagine a little tiny molecule onto the end of some of these bigger molecules

to make them detectable to the SAM instrument. Otherwise, they just wouldn't be detectable and we kind of miss them in our scans. And so when you use TMAH, it's sort of like instead of taking a sledgehammer to the wall, you're taking it apart by brick because then you know how to put it back together. So that's the way that I tell people to kind of think about these experiments. It gives us new insight into the same organic matter that was present there. We just happened to carefully pick a location that we expected to have a lot of organic matter, and it did. So how reliably can we tell that these organic compounds are what we think they are based on the fact that we're altering them with something like TMAH?

That's a really good question. So, I mean, we've been using TMAH in terrestrial experiments, like it has nothing to do with planning for planetary missions for I think probably decades at this point. So we know what to expect. We know how the molecules are going to react with the TMAH. And when they when they break down or where they're going to cleave, it's pretty well known. So well known in fact that we ran the experiment. We kind of thought, you know, a lot of this material kind of looks like what you might see from a meteorite. So if you imagine meteorites raining down on the surface of Mars or of Earth in our ancient past, that kind of material is one of the potential sources for organic matter on Mars.

And so we actually perform the TMH experiment with a meteorite, the Murchison meteorite, to understand, okay, how similar are the distribution of organics that we're seeing from our Mars experiment and from this meteorite? And it turns out a bunch of the molecules that we saw on Mars are actually pretty consistent with what we saw in Murchison. So we've been thinking that what we actually did was break apart ancient preserved carbon or organic matter that might at least be partially derived from meteorites that rained down on Mars more than three and a half billion years ago. So it's reconstructing, I think, so many processes in the ancient past on Mars and gives us this really cool suite of organic some of the molecules which we've never seen before on Mars. That's so cool. because I know that you found a lot of aromatic hydrocarbons and things like that.

And it's not like these can't be made inorganically, right? We've seen them in gas clouds and space and things like that. But the fact that we can then think, like maybe these were formed in space, formed these meteorites and then rain down on Mars is just so cool and tells us so much about the history of our solar system and its connection to the broader area around us. Absolutely. You know, I think sometimes people are like, well, why can't we say it's indigenous to Mars? like this organic matter. And we can't say completely that some of it isn't, right? But when you look at

sort of the character of the suite of organics that we released with this experiment, it's the most parsimonious interpretation to say, at least some of these look very meteoritic to us. But the excitement, of course, is always like, how complex of a molecule can you get to maybe say something more specific about its origin? Of course, curiosity is a not a life detection mission. It's a mission meant to characterize habitability or environments where life would have wanted to live in the ancient past if it was there. And I think that we have accomplished that profusely with this mission, right? We've identified so many environments, including Mary Anning, which contained this organic matter that if you think about it, you know, raining down on Mars more than three and a half billion years ago, it's the same kind of stuff that was basically the feedstock for the origin of life on Earth. That was what was raining down on Mars as well.

And so even if that organic matter isn't telling us about, you know, know, a potential ecological, biological, whatever ecosystem on Mars, it does tell us that so many of the building blocks for what we know life to be on Earth, we're also present on Mars in the ancient past. Well, you mentioned this is like 3.5 billion years ago is about the timeline that we're thinking here. Is that because of the age of Gail Crater, or did you do some dating process on the rock itself that tells us how old this sample is? Unfortunately, no, we don't have the ability to do radiogenic dating in that way with really any current missions right now. And so what we, we have to do a little bit of hand-waving and here's how we do it. We have an idea roughly for

when Gail Crater might have formed and then we have an idea for when water started to dry up on Mars. We will put big error bars on this, but we often point at about, you know, three and a half to four billion years ago. If we had samples from Mars that were returned to, to our terrestrial laboratories, we would actually be able to perform the type of radiogenic dating that we need to say exactly how old some of these rocks are. But without that information,

we can take our best guess that the rocks that we sampled for this experiment were clearly laid down by flowing water in Gale Crater in the ancient past. And we assume, based on like crater counting and how we are sort of building up our story of the strata of rocks on Mars, that if water stopped flowing roughly three

a half billion years ago, we are going to lean into this being maybe three and a half billion year old material. It could be older, it could be a little bit younger, but it's still, you know, giving us an insight into rocks that for the most part, we don't have very many rocks of this age left on Earth. And so seeing something like this on Mars not only gives us insight into, you know, this ancient Martian environment, but it gives us a sense for what very early Earth might have been like as well. It gives us sort of insight into planets basically in their infancy. I love the imagery, too, of these potential meteorites falling down on Mars, encountering water, and then being flowed into this rock and then it encapsulated for all of this time. It says to me that,

you know, this is just a really great place to look for these kinds of organics. It's almost like a little time capsule situation. And that's one of the reasons I think Gil Crater was so appealing to us from the very beginning. You know, it presented this suite of environments, this transition from a wet planet to a dry planet, at least in the regional scale with Gail Crater. There's so many cool things to explore. And we're still exploring this stuff today, which is like what blows my mind. I don't think I got to talk to the audience last time about this, but I started working with curiosity before we ever launched as a graduate student.

And so I've had the opportunity to sort of grow up with this mission and see it, make all of these extraordinary discoveries. And the fact that we are still moving through, you know, we just finished up working in the boxwork area, which is where we have this sort of preserved subterranean groundwater system. We are, you know, moving toward what we call the yardangs, which are these aeolian or wind-sculpted features that I remember seeing from orbital images. And I remember seeing the first time we looked up at Mount Sharp and took our first images from the crater floor and thinking, you're never going to get all the way up there.

And man, we are pretty doggone close now. So just, you know, it's a good reminder. like we did this experiment six years ago, but like we are still doing extraordinary science with an extended mission. I think we're in our fifth extended mission now. I mean, we just, we just keep going. It's amazing how much longevity these craft have had. You know, they're consistently, so many of these rovers and spacecraft are living far beyond their expected lifetimes. I'm so glad that, you know, it's still going in the vein of opportunity. I'm hoping it makes it to at least 15 years. I know. Yeah.

Yeah, I guess it would be sort of a bittersweet milestone to surpass opportunities lifetime on Mars. But, I mean, if you want to talk about expected duration versus extended mission, opportunity, still holds that award. And I think we'll for a very long time. What are some of the organic compounds that you actually found in this sample? And do we find a lot of these on Earth? We must. I mean, we're covered in organics, right? We certainly are, yeah.

And so these are all, like, I would say relatively simple molecules. So as you were describing before, they're what we call aromatic hydrocarbons, many of them. So what does that mean? Hydrocarbons mean that you have carbons bound to each other and they have other molecules, often hydrogens on them. And when you have an aromatic, those carbon molecules have actually bound themselves into a ring structure. So like five or six carbons all bound together in a circle, basically. So we see those types of molecules, sometimes a single ring, which we call a benzene,

sometimes a double ring, which we call a naphthalene. These have a bunch of sort of functional groups on them, which make us think that they broke off of a larger macromolecular thing. So that means like a larger chunk of organic matter. That would be pretty consistent with the kind of stuff that we know would have been delivered by meteorites. But some of the molecules that are not just carbon and, Hydrogen, one of these is a molecule called benzothiophen. If you think back to your root words like

thio, that means sulfur. So the benzothiophene is actually two of these carbon ring structures bound together and they have a sulfur molecule mixed in there. Now, benzothiothine is really cool because it does form in the modern. It forms on Earth as well. But we know that some of this from meteorites actually formed very early on as our solar system was sort of condensing out. And so I like to think, you know, there's the chance that maybe this is some of the original benzothiophine that condensed out from our solar system on meteorites and rained down on Mars. Who knows if that's truly the case.

But the fact that you're sampling this really ancient material from our solar system, I think just ties even more greatly into sort of the really, like, lovely deep time ecosystem that you see forming between meteorites and plus. planetary bodies forming and and as those planetary bodies evolve. I just find all of this to be like this like really beautiful musical little like dance that the organics are doing. They're just living their organics life, but I find it to be this gorgeous thing. One of the other molecules that people were really excited to chat about with this discovery is something called a nitrogen heterocycle. So I'm not using a molecule name because we aren't quite sure which molecule it is. It's probably

related to what we would call an endol. And so this is, if you, if you picture those carbon rings, it's a two ring structure. And instead of the sulfur being in the ring, there's a nitrogen in the ring. That's really exciting because these types of molecules like endos are actually some of the precursor molecules that eventually build up to making DNA, which I think most people are familiar with is bringing the genetic material that drives all life on Earth as we know it. So it's not that we found DNA. It's not that we found evidence for life, but we did find those building blocks for sort of the key molecules that we know life requires, at least on Earth. And so this is the first time we've seen a molecule like that, a nitrogen heterocycle on Mars. And so I think with

each of these discoveries, we're just expanding sort of the library of things that we recognize are or were present on Mars that could have fed into a habitable environment, maybe even having the building blocks for life as we know at present at the same time that life was originating on Earth. So it's a really, I think it's a really exciting discovery feeding into our understanding of the habitability of Mars in the ancient past. I love that we're doing this kind of experiment because it's the first time we've seen that kind of thing on Mars, but we now, because of our sample return missions, have found the precursors of things like RNA on asteroids like Benu. So the fact that these kinds of chemicals are just strewn about our solar system and probably

strewn about the entire galaxy and beyond just says so much about the potential for habitability on worlds that I think we're only beginning to try to unpack. I absolutely agree. It's really exciting to see the things that we expect to see, but we haven't seen yet. And every time you have just that, sometimes it feels incremental. You're just like slightly pushing forward the boundary of our knowledge. but that's how you do science. And that's especially how you do science on planetary missions.

I've been so excited to see our sample return from Benu giving us this insight into these building blocks for life. And we see that in situ on asteroids, now we're seeing it present and preserved on major planetary bodies. I think you're right. I think it's everywhere. And the fact that it's been preserved on Mars for this long is also really impressive. because that suggests that more complex organic matter is capable of being preserved in the

relatively near subsurface of Mars. There was a while where we thought that the radiation environment, which is incredibly harsh, would be destroying everything to a certain depth. And while that is, that is true, it is still a really harsh radiation environment, we're starting to recognize that perhaps when you have these larger organic matter deposits, that they are actually able to resist some of that radiation degradation or at least able to preserve enough that when we roll up and do an experiment, we're actually able to see it. It's interesting that you point out the degradation of these chemicals because of radiation, because I know I've read papers about the formation of these chemicals in space and how radiation

can actually contribute to the creation of them. How does that work? It's always a balance of building up or polymerizing and breaking down or degrading. It really depends on the environment that you're in, whether you have oxidants. I think part of the reason we were able to discover what we did in the Marianne sample is that you had that organic matter bound within those clay minerals. That provides some additional protection on top of this being more complex and what we call recalcitrant organic matter. That's going to be a little more resistant to degradation.

One of the other things about Gail Crater, you know, we, I think, mention every once in a while and then we kind of carry on with whatever science we're talking about, but Gale Crater was filled in with sediments at one point. So Mount Sharp in the center of Gale is five kilometers tall. I mean, this is a pretty big mound of sediments. And that entire crater was filled all the way up to its rim at some point in the past and then eroded back down by aeolian or wind abrasion. And so we have to picture that, you know, the water was flowing, the rocks were depositing, the organic matter was getting preserved, and then all of that was buried underneath a stack of basically rocks sediment for some period of time. Again, if we had some

samples back, we might be able to constrain that time frame better, but I think that in part may have led to some of the preservation of these organics, because it's not like they've been sitting at the surface for three and a half billion years. They actually had some additional sort of geologic protection for a while. That's even better reason while Gail Crater is such a great location for doing this kind of science. That's amazing. Out of this experiment, could you tell the relative abundances of the different chemical compounds? For some of them, we were able to get estimates. I mean, we're still dealing with like pico moles of material. It's still very lean. Some of the molecules, like that nitrogen heterocycle, we were quite refined in being able to extract the spectra from the original

like SAM data to be able to get at those kinds of details. But for some of the more abundant molecules like the benzothiophen and naphthalene, we were able to get some constraints. But it's all in line with what we've kind of been seeing on Mars when any time that the SAM instrument has seen organic matter. So it's still lean, but we are still lean. But we are saying. seeing sort of different character that tells us there are sort of these different repositories of organic, some that are maybe a little bit more free or available to be seen with the Sam instrument and some that are coming from this more complex what we call macromolecular carbon. You mentioned the spectra of this material just a little bit ago.

Classically, I think a lot of people, when they think about curiosity, they think about like zap the rocks, look at the spectra, that kind of thing. a even more complex analysis on this sample using gas chromatography and mass spectrometry, which I had to learn more about in order to understand how this sample was analyzed. Can you tell us a little bit about how this process works? And we might have to break it down. So what is gas chromatography? Yeah, we can break it down into the two components of the SAM instrument. It actually has more than this, but we won't worry about that right now. So gas chromatography is when you take a sample and you somehow get it in the gas form.

In our case, we're heating it in our oven. And so when you get it into a gas form, you can actually flow it into a little tiny, basically capillary column. This thing is 30 meters long and, oh gosh, 0.25 microns in the interior diameter. So it's incredibly thin and super long column. And so what you do is you move

those gas molecules through the column and the basically think of it as the chunkier molecules, the larger ones are going to move more slowly than the smaller molecules. And so you end up separating, that's the chromatography part, separating the molecules out based on their mass. And so as they move through the column, at the very end of the column, they get to the mass spec. So this is a way of ionizing those gases so that you can detect the molecule. And so, So the smaller molecules will come out first, and then the larger molecules will follow. And so that is the combination of separating out the molecules and sort of what time they get to the mass spec tells you one part of their identity.

And then the actual masses that are represented in the mass spectrometer tell you the other half of their identity. And so we get both of those pieces of information back, but then we have to do a bunch of bench top experiments here on Earth to confirm what we're seeing. So if you have a molecule that has, like there's a lot of molecules that can have very similar mass spectra, but some of them are going to take much longer to get through that column than others. And so it's actually us testing those molecules and seeing when they come out of the column that helps us refine their identity. We'll be right back with the rest of my interview with Amy Williams after the short break.

Hi y'all, Lovar Burton here. Through my roles on Star Trek and Reading Rainbow, I have seen generations of curious minds inspired by the strange new worlds explored in books and on television. I know how important it is to encourage that curiosity in a young explorer's life. That's why I'm excited to share with you a new program from my friends at the Planetary Society. It's called the Planetary Academy and anyone can join. Designed for ages 5 through 9 by Bill Nye and the curriculum experts at the Planetary Society, the Planetary Academy is a special membership subscription for kids and families who love space. Members get quarterly mailed packages that take them on learning adventures through the many worlds of our solar system and beyond.

Each package includes images and factoids, hands-on activities, experiments and games, and special surprises. A lifelong passion for space, science, and discovery starts when we're young. Give the gift of the cosmos to the explorer in your life. I was wondering, too, as I was reading this, how do you figure out what might be left-over remnants from Earth or other parts? of the machine itself. And so much of this paper is about trying to disentangle all the things that could be misleading within the data. And part of that is the instrument itself.

So you did these kind of like dry runs, basically like control runs on this experiment. How does that work? So the, like I mentioned before, there are only two cups on board, this, you know, 74 cup instrument that had the reagent in it. And so we had the choice of you could use one. of these cups and do a total, like an actual instrument blank where you are running that that reagent through the column and seeing, you know, basically cleaning it out, seeing what your background is, and then doing the experiment. But that means we would only have one experiment

from flying TMAH. And so we had to make the hard decision to do what we called a dry run, which is sending the instrument through all the paces that it would and seeing what the background looks like in what the mass spec is basically reading that's in our in our columns and our lines that organic background that we know is present and then then running the sample with with tmah h and basically doing a comparison between what's there when you when you use the exact same program same temperatures everything versus what's there when you react the sample with the chemical so you know that is part of the challenge of doing stuff remotely or on fly because sometimes you only have one chance to do something.

So don't mess it up. And if you do mess it up, all right, what data can you still get from this, right? Still making this a useful experiment. We got really lucky. We were able to bypass a lot of the, I think, the trips that we could have run into along this experiment. We actually were planning to perform this using two. There's six gas chromatography columns on board Sam.

And we were planning to use two specific ones. And one of them got clogged right before. the experiment. And so we had to pivot in pretty real time to using a new column that we hadn't used before. And in the end, we got fabulous data from it. But it's all sort of that you have to be ready to respond in pretty real time to changes or, you know, curveballs that Mars likes to throw at us. Right. Plus, I know this was a few years ago, but you also have to deal with the fact that some things within this instrument itself might degrade over time. And I know a lot of this paper was dedicated to talking about specifically the TNX trap. Can you talk a little bit about what that is

and why that was such a like a thing that you really needed to analyze in order to get this experiment right? Yeah. So if you picture how this this gas chromatograph mass spectrometer works, one of the things that you can have on it is what we call a hydrocarbon trap. So basically a way to let some of the other molecules that you're not interested in flow through the system, but to trap the molecules you're interested in so that you can then re-release them to analyze them, you get much better data that way. And so one of the trapping materials is something that we call TNX. It's a kind of resin. When we release the molecules from that trap, you heat it up to do it, right? So heat is the way to kind of mobilize these gases through the SAM system. When you keep heating up TNX over and over and over again to, you know, not even a very elevated temperature, you can start to have some,

degradation products. And so those are things that we expect to see. And we've seen previous experiments. But, you know, when you put a new chemical on there, we had to basically figure out which molecules might have come from the TNACS reacting and which ones were actually the molecules that we had tracked and released from the sample. So yeah, we spent a lot of time kind of figuring out what's likely to have come from the TNACS trap. And there's a couple of molecules, very simple little things, but those that we just need to be aware, you know, we've seen them another SAM experiments. Some of them probably or may come from TNX, but then a lot of the molecules we saw with the TMH experiment, there's really not a good way to explain how they could have come from the TNX.

So it's all about being, I think, responsible with how we report the data, identifying what are the possible things that could have caused us, you know, trouble or giving us a background signal. and then just trying to be very reasonable and robust in our interpretations of what we think is orthogenic, you know, is indigenous to Mars to the sample. Yeah, it takes a lot to separate out all of this data. But in the end, I mean, we've been talking a little bit about like the age of this rover and how that might contribute to degradation. But it also means that we have a wealth of information on how this instrument works and everything that's been going into it. So maybe in the end, it's a little bit of a double-edged sort. it can help you as well. Yeah, yeah, absolutely. You know, we've been characterizing the background for

years now. We've done so many different kinds of SAM experiments that we have a wealth of data to work from. So we can feel pretty confident in the identifications that we've made for this study. Well, we talked a little bit about how radiation in the environment could alter these rocks and, you know, potentially change these aromatic hydrocarbons. But what about the thermal history of this area? Like, things have changed a lot on Mars since these were deposited. They have, but I think when you consider it in sort of a geologic standpoint, it hasn't been all that dramatic. So there's always the thought that if you bury rocks on Earth, let's say, if you bury rocks to a certain depth, then they can thermally mature. There's a big discussion about whether, like, how deep would you have to bury rocks on Mars in order to have a comparable type of what we call diogen?

And so we're not thinking that these rocks have experienced that level of alteration. There's definitely diagenetic fluids that have moved through Gale Crater and Mount Sharp throughout sort of the time frame that water was active on Mars. But that would be more like fluid interactions and less so that they've been thermally matured and sort of the way that we think of it on Earth. So that's actually something that we feel like we can say it's not going to be that big of an impact. Maybe even having the colder temperatures of Mars being a cold, dry desert now, perhaps that actually improves preservation of these organics over deep time. Well, meteorites might be a way that this material came down to Mars. But what are some other abiotic explanations for how these were created?

So there are definitely geologic processes that are capable of generating organics. We often think about sort of these abiotic processes at like hydrothermal systems or in like serpentinizing environments. In the Marianning area, we didn't really have evidence for serpentinites. You know, we have had regions that seem to have experienced some hydrothermalism, but not necessarily where we were at Marianning. But, you know, these clay minerals are really good at. at preserving organics that may have come from other places. So it's not to say that there couldn't be a geologic component to these organics that we saw, but you just have to expand sort of your assumptions about where the organics may have come from. So yeah, there's sort of the two

types of abiotic ways to make organic carbon are geologically or on meteorites. And who knows? I don't want to speculate too much, but we don't know. how habitable Mars was in the past, right? So who knows what other biologic processes could have led to this, but that's just something we don't know anything about. Yeah. And fortunately, because of the nature of the sort of the size of the organics and what they look like, you can't really say that anything was biologic. And of course, you know, I keep arguing. I feel like I'm the most pessimistic astrobiologists, but we need extraordinary evidence to support an extraordinary claim molecules like this, they can be formed biologically, but they can readily be formed

abiotically as well. And so I think it's so important for us to have, if we're going to ever claim having evidence for ancient life on Mars, I think we need to have some really robust data and something that has maybe like corresponding lines of evidence that come together and make us feel confident in a claim that is that extraordinary. For now, I'm very satisfied to think, you know, this stuff looks like the building blocks for life. You know, at least we're answering some of those habitability questions on Mars and, you know, we can leave the search for life to perseverance, Rosalind Franklin, maybe one day some iteration of Mars Life Explorer will fly. So I can always be hopeful for our upcoming, actually, astrobiology focused missions.

Well, the fact that you found these in this specific location doesn't surprise me a whole lot. It sounds like these rocks were well preserved, but you only did this experiment in one location. So we have no idea how prevalent these chemicals are on Mars at large. And now I'm wondering what we could do, if we could bring a sample of this rock or even samples like the ones that Perseverance has been caching, what we might be able to do to piece apart how many different organics are in these rocks if we could bring them into an Earth lab versus using the experiments on a rover, which are, you know, they're wonderful, but they're limited because of their size and what we can send to another world.

No, it's totally true. And I'll tell you what I'm finding more exciting. The more that I'm digging into, not only like, you know, the work that I've done and that the SAM team has done, but actually across Mars, what I think we're starting to recognize is that there is evidence for this more complex organic matter, what we call macro molecular carbon. So we've actually had hints of it in different locations in Gale Crater. So we've seen other features in SAM data that have made us say, man, that really looks like it might be coming from some. something more complex, a larger kind of organic matter deposit. This experiment is specifically designed to break apart macromolecular carbon.

And so getting the data back from that was like a really strong confirmation that we've been seeing macromolecular carbon. And then we also have evidence for it actually with the Perseverance Rover. Several of the locations that we've explored using the Sherlock instrument has shown us with the Ramon spectra, the presence of these peaks that are associated with macromolecular carbon. So now we have different instruments on different missions and different locations coming up with similar explanations for the organic matter that we're seeing on Mars. So I think you're right. I think that there is more macromolecular carbon in the relatively shallow subsurface of Mars and that there is more preservation than we had initially maybe, I think, rightfully anticipated. And the fact that

we're detecting these kinds of compounds on space rocks and in space clouds. Just, I know I've said it already, but that is absolutely startling, that the ingredients for life are just all over the place and just sitting in this preserved rock from 3.5 billion years ago. Yep. Yep. I think that it probably speaks to, I think it gives us more context for the origin of life on Earth, that these molecules are pretty prevalent.

It's probably very, I guess I would say. say like energetically favorable, likely to occur reactions, those chemical reactions that kind of kickstarted in origin for life on Earth. And I mean, it makes sense to me that these same molecules are going to be present at least throughout our inner solar system and probably throughout our full solar system. Well, when last we spoke about finding life on Mars, you told me that it was kind of like a childhood dream of yours. And this isn't definitive evidence of life on Mars, right? Clearly not. Correct.

Not at all. But this is one more step in that story of us trying to understand whether or not it was even possible. And this is a really exciting step. I mean, the wealth of the different compounds in this sample just absolutely blew my mind. Like, how surprised were you when you did this analysis to see how much of that revealed itself? I would say that I wasn't surprised, but I was very pleasantly relieved maybe because This is what I anticipated and I really hoped for. And so it was definitely a relief to say, okay, we made the right choice with the sample that we collected this from.

And the experiment worked the way it was supposed to. So, I mean, the spectro were so complex with this particular experiment. You know, we picked apart as much of it as I think we reasonably could. We're trying to get these data published for the community to be able to use. But I think that there's more work that we can do to search for, of maybe smaller peaks of molecules that are less well represented, but to just get some more information out of just this single experiment. I think that there's so much more we can keep doing with just one experiment. And you're right, like each step here is an important,

an important step on the path to addressing the question of whether there was ever a life on Mars. Sometimes again, it feels incremental. But remember, you know, to make these extraordinary claims, let's have the best basis, the best evidence that we can to build up to an extraordinary claim in the future. And I think this study is one of those that can hopefully lead us in that direction one day. And it's just years in the making. This took a lot of time and a lot of planning. This is your team, but it's also the thousands of people that worked on the spacecraft and sending it out there, all the people that worked on the science before. This is one of those things that that literally has taken decades and decades of human ingenuity and love to accomplish.

So I'm just so excited about this kind of result. It tells us so much about ourselves and about Mars. And I'm just so happy for your team. Thank you. Thank you so much. And yeah, it's a huge shout out to everyone who came up with the concept of having the Mars Science Lab to those who built it to all the instrument teams that contributed and the scientists and engineers that operate that mission today.

I mean, they're extraordinary people doing extraordinary. work on Mars. And I just feel so honored to have this little spot to be able to highlight the amazing work that they're doing. Well, thanks for coming back on our show and telling us all about this. And I hope that those people in the line at the Smithsonian get a chance to listen to this so they can learn more about the result that they were so excited to share with me. Yes. And thank you so much to those folks for telling Sarah about this because I love any excuse to get to chat the planetary radio. Thanks so much, Amy. Good luck in your future research. Thank you.

What Amy's work really highlights is just how patient planetary science has to be. An experiment performed in 2020, analyzed for six years, revealing chemistry that's been preserved for three and a half billion years. And yet there's still so much more that we can learn about Mars's ancient past. The good news is that this kind of experiment doesn't end with curiosity. The TMAH experiment that revealed all of these molecules is also planned to be on board the European in space agency's Rosalind Franklin Rover. NASA recently selected a Falcon Heavy to launch that mission in late 2028, though the mission is currently facing uncertainty due to proposed NASA budget cuts. If and when Rosalind Franklin launches, we'll be able to do a similar experiment on a different

part of the planet and see if that organic richness is widespread across Mars or unique to Gail Crater. And it's not just Mars. The Dragonfly Octopter, which is going to be headed to Titan, Saturn's largest moon, is also going to be carrying a TMAH experiment, along with a wealth of instruments designed to detect organic molecules in that world's unique chemistry. Dragonfly is also launching in 2028, so that's going to be a really big year for planetary science. Altogether, these experiments could reveal whether the basic building blocks for life are as common across our solar system as we're beginning to suspect. But we're just going to have to be patient for the results as any good planetary scientist would.

But first, let's check in with Dr. Bruce Betts for What's Up and our weekly random space fact. Hey, Bruce. Hi there, Sarah. Man, another really cool paper out of Mars. But also, I'm noting this as I'm having more conversations about samples and sample analysis. We're finding a lot of really cool organic stuff

just all over the solar system, the more that we're looking. Yeah, it's very, very common. and we care, sort of, because it's that life thing. You need, makes up life. So that's presumably why certain scientists get all excited when we find things lying around that use the scientific term organic, not to be confused with other uses, organic, more common in general usage. And in fact, organic. I'm sorry, I've given my little speech about organic and chemists.

It's a funny term. I mean, it's like stuff that uses carbon. and carbon is really flexible and does life, but like not everything that uses carbon. Like we don't like certain simple molecules. We're not in the mood for that. That's not an organic. And according to Wikipedia, one of the first sentences they state is basically not all scientists agree on what organics means. But we mean lots of carbon, especially in long chains and stuff.

So, yeah. And you know, Benu, with Osiris Rex, they found. In fact, as you said, we found wherever you look, you find these things. It's like, I mean, literally, it's under your fingernails. I think that was the really interesting thing about the Benny results, but even these ones from Mars, right? Like, and I don't know if I would ever say that at any other point in my life. I wish I had taken organic chemistry, the class that everyone in college dreads. Yeah, most people say I wish I had never had to take organic chemistry.

Exactly, but there's so much about this. you know, as you point out, organics can mean a lot of different things and only some of them are important to life. But the stuff that they found on Mars recently, it's all kind of like precursors of what we need for like nucleo bases and stuff like that. And the Benu samples similarly were just so complex. But we learned so much more about them because we could take them into a lab. So if you could like do an analysis of what's in these things, like how do the organics on Mars compared to what we're seeing and the samples that we've collected from asteroid Benu? Well, that's a simple question with a non-simple. answer. Well, first of all, you've got your polycyclic aromatic hydrocarbons. Always.

To say. And you got those in both places. And they're also in carbonaceous meteorites that were one of the pieces of evidence that later was not really considered evidence in ALH-84-O-1, the Mars meteorite was thought to have evidence of past life. So that's both places. You got sulfur-bearing stuff. You got all sorts of nitrogen-rich. good stuff and you said nucleobases. Benu has all five nucleobases. But the fact you got this stuff lying around being delivered by asteroids, popping up on all on different planets,

it certainly you got the pantry stocked. That's the real point. And it may help form life. Right. But you don't just need the ingredients, right? You need the right circumstances for life. We found that maybe these things exist out there, but finding a place where they can all percolate together to form something like cats and dogs and us is a whole other story. Because just because it has water, just because it has energy, like that, even that itself doesn't necessarily mean that you're going to build life there.

So I don't know. But it bodes well anyway. So anyway, shall we move on? So you drive. I drive. You drive. You drive. Yeah. Yeah, you know what a car is. If you took a car in space, which is only done in fast and furious movies and on SpaceX rockets, but you actually were, okay, this is a theoretical, if you drove a car straight to the sun from Earth, which also wouldn't work because of orbital dynamics, and you drove at freeway speeds, it would take you over 170 years to get to the sun.

Oh, my gosh, that's the worst road trip in existence. No. if you drove to Neptune, straight to Neptune, freeway speeds, no brakes, no stopping off at the local mark, no stopping for gas, it would take you 5,000 years to drive to Neptune. And I'm assuming it like, you know, freeway speeds are in the United States like 65 miles an hour, or are we speeding on our way there? Well, you probably are eventually because you get bored. I went with the, because we have 10 fingers and 10 toes, and I like the metric system,

I went with 100 kilometers per hour, which still uses hours, but we're stuck with hours in seconds that horrid system. So, yes, because it was easy, I used 100 kilometers per hour, so 62 miles per hour. Close enough. Yeah, probably, yeah, not speeding in most places. Well, I guess you just need to gather up all the snacks, which are, made of organics. We get the organic snacks.

We put them in the car. We'll drive to the sun. I think it's hard to find snacks that aren't organics in the chemistry form. I don't know, man. There's some candies in the United States that I would question. Yeah, I didn't really think that went through. So anyway, how about everybody go out there, look up the night's guy and think about my dog, jumping into the air to catch a frisbee because that's what we'll be doing shortly.

But don't worry, he's chewed the frisbee up. first, thank you, and good night. We've reached the end of this week's episode of Planetary Radio, but we'll be back next week with more space science and exploration. If you love the show, you can get Planetary Radio t-shirts at planetary.org slash shop, along with lots of other cool spacey merchandise. Help others discover the passion, beauty, and joy of space science and exploration by leaving your review and a rating on platforms like Apple Podcasts and Spotify.

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And until next week, Ad Astra I don't know.