NASA's Curious Universe - How NASA Found the Ingredients For Life on an Asteroid

Episode Date: January 29, 2025

How did life begin? It’s one of science’s biggest questions, but it’s impossible to answer on Earth, where ancient clues have been buried by the planet’s shifting surface. Instead, scientists are looking beyond our own planet, to asteroids like Bennu, a distant fragment of a lost world. In 2023, NASA’s OSIRIS-REx spacecraft collected a sample of Bennu’s surface and brought it back to Earth. Ever since, scientists have been hard at work studying the fragments of asteroid Bennu. Now, they’re ready to reveal the results—our best look yet at a time capsule from the early solar system that once fostered the ingredients for life. 

Hey, space nerds, this is NASA's curious universe. I'm your host, Patty Boyd, and today, we are diving into some of the biggest unanswered questions in science. How did we get here? How did life start on Earth? Some of the answers could come from asteroids in our own solar system. So NASA sent a spacecraft called Osiris Rex to sample one, an asteroid called Benu. In the 16 months since NASA scientists cracked open the sample canister, they've been carefully studying the rocks within.

And now, finally, they're sharing some exciting results. In new research, the Osiris Rex team reveals Benu, carries organic molecules, the building blocks of life. We're going to talk about all of this with Jose Aponte. He's an astrochemist who works with the Osiris Rex team. He is one of the few people. who gets to get up close and personal with Benu. Jose, welcome to Curious Universe.

Thank you, buddy. So how did you first get interested in space and in studying asteroids like Benu? Wow, that's a difficult question to answer. I'm a chemist by training, so I got my bachelor's in chemistry. And I didn't know anything about space. I didn't have actually curiosity about space at all through my undergrad and later graduate schools studies.

So I'm originally from Peru, and that's where I obtained my Bachelor's degree in chemistry, and then I came to the States to pursue my PhD in organic chemistry. And so I saw this ad that they were looking for an astrobiologist to analyze organic compounds in meteorites. And so I was trained to analyze organic compounds in terrestrial samples. I mean, I didn't know anything about asteroids or meteorite, but I found it really interesting. So I applied for that position, and that's where my journey at NASA started. That's so cool. Was that the first time you had heard the word astrobiology, or did you have some sense of what that meant?

For sure, I didn't. I actually, I had to be honest, at first, the very first time that I read that word, I thought it was kind of fake. I had to go to Wikipedia and search it. And, you know, after reading about it, I thought, wow, this is the craziest most exciting thing ever. Totally. Very cool. So tell us a little bit about this asteroid Benu. What does it look like today?

Where is it in the solar system? So Asteroon, it's a small object in the solar system that is sort of between the Earth and Mars. And it's a rubble pile type of asteroid, which means that you can think of a bunch of different rocks that were put together. and they aggregated into this body. And this mission, OREX, will help us understand how that rubble pile was formed and where it originally was created and what it contains inside. Great. So before we get on to Benu and what we're learning from Benu, can you just sort of walk us through like the life story of Benu? When did that rubble pile actually come together?

And where do we think it was at that point in time? like what was its journey from the beginning of our solar system to where we are today? And how do we know that? Okay. So that's a question that we didn't know before we went to Beno. So it's a question that we are starting to answer only now that we are analyzing the samples. Because we are discovering several organic compounds and several actually elements and salts and minerals that can only be formed in a place in the solar system where,

the type of compounds can solidify. We typically call that the snow line. It's where water in the solar system kind of freezes. Can you just remind us where the snow line is between our favorite planets? Is it Jupiter to Saturn sort of in there? Well, before Jupiter. Okay, so somewhere between Mars and Jupiter is where the snow line is. Yeah. Okay.

And so if it goes farther inside the solar system, it becomes vapor, and so it will escape to the formation of a solid. of a solid body, right? So based on the materials that we've seen in Benu so far, we tend to think that Benu is a daughter fragment of a bigger body that at some point was orbiting behind the snowline, meaning farther out in the solar system. But the curious thing is that Benu is inside the solar system.

So that means that something happened, where this initial parent body that was living in the outer part of the solar system somehow first got destroyed into several pieces and second, those pieces somehow ended up in the inner part of the solar system. That's so cool. So it's basically got the secrets of the early solar system and the outskirts of the solar system locked in there. And now it's close enough that we can talk about what's in there.

So how big of a deal is it to have a sample from Benu? We already have material from asteroids in the form of meteorites that have landed on Earth, right? Benu is in other space and their vacuum and they're really cold conditions. And so anything like that that crosses our atmosphere that is full of water, full of organic matter in the air, it's going to be just different. It's going to start decomposing. Actually, that's something that not many people realize is that what we see, in meteorites today, we first don't have a context of like when it will come unless you see

it fall and then you pick it up, but that's kind of rare. But if you collect meteorites in Antarctica, for example, those meters could have been sitting on the ice for thousands of years and you don't know, right? And then so you don't know where it exactly came from, like they come from the inner solar system, that it come from the other solar system, what is the part and body of it? Like, they come from a planet, from a moon. So it's just random. You assume that, you know, it's...

Right. But you don't know for sure. So we have so many questions about those meteorites about their origin story. And, of course, a contamination that you can escape. You can really not escape from the... of contamination on the Earth. Like, it's just impossible. So here we've got a pristine sample of an object whose history is very well known to us compared to those.

Right. That is so cool. So it took Osiris Rex seven years to bring a sample from Benu to Earth. That's a long time to wait. So when you first got your hands on the sample, can you set the scene for me? Like, what was that like? I'm a little bit different, I guess, from everybody else. I thought I was going to be super excited.

But then when the moment comes and you have to handle the material and you have it in your hands, you got to be really careful. So you got to take the emotions out of it. You got to focus on what you're doing. You got to be careful with each step that you take. And so my approach is like thinking, this is not valuable. I mean, not that I'm going to throw it away. Let it fall in the floor or something. But, you know, be methodical about it and not so, I guess, passionate or nervous about it.

Besides, there was a delay on the delivery of the samples. Okay. So it sounds like your anticipation phase was like waiting for things to get here. But then once the job was here and to do it, you go in a work mode. You're going to just get the job done. I even told my wife, like, by the end of 2023, I prepared her. Hey, through the Christmas holidays, I'm going to be working. I'm going to be an analyzing venue.

and so there's no vacations for us. But I guess, yeah, it is what it is. So you're talking about the samples from Benu and having them delivered here to Goddard and when you're about to work on it. And I'm trying to imagine what that looks like. So are you like in a clean room, in a bunny suit, like touching rocks with gloves

or are the samples different than that? No, absolutely. We have what we call a clean room. It's a cleanish room. I mean, it's not under vacuum or anything, but yes, we have to gown up, put in a hair nest, a mask in the face, gloves, and then covering the shoes. And so we get into this room where the atmosphere is cleaner. And then we have special chambers that blow clean air. there's a positive flow.

So things cannot come in that chamber. Things only go out, right? And so that's where we place the samples. And so far, it's been great. What does the sample look like? So, yeah, the samples, I mean, they are really dark. They look like charcoal, literally. You wouldn't be able to distinguish, like, naked eye,

Like, is this charcoal or is this meteorite or Benu? You wouldn't be able to tell. But, so, okay, so we get the samples in what we call the Eagle containers. So the Eagle containers are these sort of metal tubes that are sealed under nitrogen gas inside a special facility unit where they curate Beno. And so they weigh the sample there inside those nitrogen gas chambers. And then they shipped them to a Sierra Goddard. And then we open those containers in this clean room that I was telling you about. And hopefully by that time the sample has not absorbed any of the earth water.

And it remains as pristine as possible. And so that's where maybe if we need to crash it, we crash it. That's where the fun starts. So can you give us a sense of how long did it take to start doing these measurements in the lab? Is this something that was like a day? You had to, you know. No. I mean, it sounds like, oh yeah, you get the sample and you do the analysis, right? No, the development of the methodology is very laborious because you're working with

these mineral rocks that contain trace amounts of organic materials. And just think that your fingerprint will contain thousands more times more organics than the actual rock that you're analyzing. Wow. So the sensitivity of your instruments have to be tuned for that low concentration. So the challenges that we face are contamination and the limits of detections. And usually the methodology to investigate these species in our lab could take any time from six months to maybe a couple of years. Wow.

And then even then, when we think that we are ready to finally analyze a sample, once you test it in an unknown material that you don't know what the mineralogy. of this, of it, you know, you don't know its composition. Maybe your method will be completely useless. All these reasons to be so methodical, so careful, so much preparation going into these measurements. So now, okay, let's go to the moment where you're finally like starting to gather the data from the sample. And this is sort of the big reveal for this sample. So what did you find? So our first paper in organic compounds is led by my colleague Danny Glavin.

and it mainly focuses on the analysis of amino acids, although several other families of organic compounds are also being presented. That includes species that are important for the organs of life. And to make a cell, you need a cell wall. And that cell wall is made of what we call carboxilic acids. Those compounds have been found in Benu. Then inside the cell, you'll have proteins. And proteins are made of amino acids, which we have found in Beno.

And then to make life, you make RNA and DNA. And those are made of nucleobases, amino acids, and sugars. So we have the amino acids. We have found the nucleobases. Wow. So, and to make all of those compounds, you need other starting materials called aldeheism ketones. And we have also found them in Benu. Wow.

So all of those species will be described in this paper. What does this news mean for the field of astrobiology? How big a deal is it? I mean, it's a huge deal for astrobiology. It confirms all the, I mean, you say, oh, yeah, all those compounds have been seen in meter rates. But what about if all those meters were actually contamination? Right. Right.

We need to know that. So now we do. And then we are confirming that the chemical inventory of the early solar system was really big, very large, and that the molecules survive and impacts on the earth, that they could seed organics on the early earth, that we could be descending from the water in yellow body, by all means, could be coming from one of those asteroids that actually impacted the early earth.

Right. And that's, I mean, when you really think about it, that's deep stuff, right? Totally. So these asteroids like Beno, we're delivering water and compounds to the early Earth. So this is really, the astrobiologists are going to have a field day with this as well, right? It's putting lots of things that are big question marks now, kind of making the guardrails.

If I tell them, hey, this is, these are the compass that were available. How can you make a cell out of this? Wow. What would it take? What minerals? What water level? What pH? What can you do with this inventory?

Yeah. Right? Give me life. I know this. We're getting there, right? We're really narrowing down the space. of where we start asking those questions and pushing forward. So that's super exciting.

So talk a little bit more about those organics. So what is that telling us? How do we think they got there? Well, before the solar system formed, we know that there was a cloud because we see clouds everywhere through our galaxy and through the universe. So we see different clouds that later collapse into what will become eventually a solar system. But that cloud, what it contains is dust, ice, and all the elements that you can think of in the predict table. Right.

So they are already there. And so there is a lot of radiation that is happening in that environment. Right. From the young star, from the baby star. Right. So then while that cloud starts collapsing and forming a disk where in the middle, you'll have the sun and orbiting around there, you'll have the planets and moons. Through all that process, all these chemicals, all these elements are interacting with each other in this heavily radiated environment.

And there are impacts providing heat. And there is elements that provide heat through radioactive decay. And so there are different conditions that will propel the synthesis of larger molecules. So that's how we think that species like amino acids are initially formed in the early solar system from the cloud. Right. Right. But then when the solar system is finally formed, those processes start fade in a way, right? Because now you have a more stable system.

Right. But if you, for example, keep having liquid water and annexation. of heat, that the composition of those initial molecules that were formed from the cloud will start happening. So they will start decomposing now, not forming, but decomposing. So there will be a balance between what is made in the cloud or in the proto-solar system and what is made once the solar system is finally formed. And then those compounds will be either delivered to the earth or, well,

stay in space forever. Right. Right. Right. Those that are impacted and delivered to the earth will again be modified and more synthesis and distraction will happen. Right. So you're talking about at this period in the early solar system where we have all these

ingredients that were important for life to develop here on Earth and we had good conditions for them to be captured in Benu and staying there for so long. What does that mean for the larger solar system in life? Is it possible that Benu could have developed life on wherever it? It wasn't its parent planet, or was there, like, life being seeded throughout our early solar system all at the same time? Well, that's a very difficult question to answer. Like, are the organic compounds on the Earth and on Venus similar to those, for example, on Mars, on some other solar system bodies that are rocky, like a series, for example, a dwarf planet, or some of the moons of Jupiter, right? And if that is the case, if they are the same or if organics are different, if light could evolve, would it be similar to ours or not, right?

And that is a question that we cannot answer yet. Right. Because we have not been exposed to a different type of life. And the chemistry will change depending on the physical chemical conditions of the environment. Okay. Right. And the availability of the starting materials. Right.

So that is a question that we are trying to answer through what we call the study of biosignatures. Right. So even on the earth, like when we dig for dinosaurs or fossils or oil, right, that is organic matter that has been destroyed and decomposed. And that organic matter somehow resembles that of the organic matter that is present in meteorites. Right. So imagine that, you know, we wouldn't know what life is or what life looks like in the earth. And we were able to analyze those two different rocks, one that is coming from the dinosaur juice. And one that is coming from the asteroid.

How would you differentiate? How would you know which one was coming from life and which one was coming from known life if they are so similar? Wow. Yeah. Right. So those are techniques and results that we need. We are only now kind of trying to answer. Actually, in the last two years, this question of how to differentiate living residues of organic matter to non-living residues of organic matter.

It's been a topic that is really growing a lot. It's going to be such an important question for us. If you go to, say, Enceladus or Europa and you analyze the surface, And you don't see any of the organic matter that you see on the Earth. And you don't see any of the, well, a different distribution of the organic matter that you see on Earth. And there's a different distribution of the organic matter that you see meteorite. Right. Would you say, hey, there's no life here?

Can you? You can not, right? You can say, hey, it's just different. Right. But we don't know. So only by analyzing all of these different parts of the solar system. Right. And having a bigger database is that we are going to, is that we are going to be.

able to perhaps totally say, say no, there's no life there. Or, hey, yeah, perhaps it's a life that uses a different alphabet. Right. So it's basically helping us to refine our biosignatures and how we'll go after them and prune off some possibilities that aren't good or add some that would be, you know, wants to keep in mind. That's so cool. Can you tell us if there's anything that really surprised you about the Beno results

or that really excites you? Well, I guess from the organic standpoint, we are kind of surprised by the really high abundance of volatile species that it has, something that we don't see in meteorites. And we thought that meteorites were just simply depleted or these volatiles. And we thought that perhaps their parent bodies or other asteroids or other parent bodies in the solar system were also depleted. but also depleted of those volatiles. But by analyzing Venu, we now realize that perhaps it's a property that they lose when they go through the atmosphere. Wow. And we can only see in Venu because it has not been outer, right?

And it has conserved all these volatile species. And that are super important to create the building blocks of life. And yeah, that's really surprising. We were not expecting that. That's very cool. And so they give us an example of a volatile that you saw. Well, the word volatile will be different for different chemists in the organics realm. Okay.

It's molecules like carbon dioxide, carbon monoxide, ammonia. We see a high amount of ammonia. Yeah, those are volatile species that you don't typically see. You see in trace amounts in meteorites, but not like in Venu. So that was a really important and a surprising thing, right? Yeah, because, again, like those species could only survive if they were solidified at certain distance outside the solar system. Right. Or outside, I would say, I should say, the snow line.

Okay. Right. Like far from the air, far from where Benu is currently. So that tells us about the origins of Benu and the synthesis of those species. Can you just say a little bit on a person? level, what does it feel like to you to have all this information about Benu right now after years of waiting and years of work? Well, it's exciting.

It's also I feel really grateful and humbled by that experience, although I cannot enjoy it very much because I have to keep doing analysis, writing papers, writing proposals, and repeat. Take that moment, right, to kind of come outside of it and really. Yeah. I would say humbled about the prospects of doing all those analysis and having all that information firsthand. Yeah, I can't imagine, but I'm really... Like, the other day, there was a tour visit from people from the Congress, and they went to see a tiny fragment of venue. It was just a tiny, tiny frog, the size of like two millimeters.

Spec of dust. Right. But that same day, I was analyzing 200 milligrams of it. I had it like working and going through it. I, of course, didn't say anything to anybody. I didn't want an interruption. Right. But I was like inside of me, I was like, hey, I may not be that important, you know, like the congresspeople. But I have 200 grams of an asteroid in my hands right now. Right. So that's something that I enjoy, I guess. That's very cool. That's thought about it.

But it doesn't really matter. And also like just appreciating the value in that tiny little speck, right, of what you've got. That's so cool. So there's one question we always ask. What are you still curious about? Well, I'm curious about what we could find in other asteroids, in other examples that we could bring from Mars, from the moon, from other asteroids or comets or from moons in Jupiter. I am excited about the future, and I really hope that these techniques and methods that we have developed and applied so far could always get more improvement. And I hope that we are seeding what could maybe in 10, 20 years, we'll say, hey, other people smarter than me has used my techniques and make them better, right?

And that would be super, super exciting to me. I would feel great. Awesome. Jose, thank you so much for talking with us today. No problem. Thank you for having me here. That's Jose Aponte, an astrochemist at NASA. This is NASA's Curious Universe.

This episode was produced by Christian Elliott. Our executive producer is Katie Conan's. The Curious Universe team also includes Maddie Olson, Michaela Sosby, and Jacob Pinter. Christopher Kim is our show. artist. Our theme song was composed by Matt Russo and Andrew Santeguida of System Sounds. Special thanks today to the Osiris Rex science team and to video producer Dan Gallagher. If you're interested in reading more about the science results from Benu, go to

science.nets.com slash mission slash Osiris Rex. That's OSI-R-I-S-R-E-X. And if you can't get enough of asteroid science, check out our 2023 episode, special delivery from outer space. Our producers captured the nail-biting moment when the Osiris Rex spacecraft dropped its venue samples to Earth. As always, if you enjoyed this episode of NASA's Curious Universe, please let us know. Leave us a review, share the show with a friend. And remember, you can follow NASA's Curious Universe in your favorite podcast app to get a notification each time. and we post a new episode. This is an official NASA podcast.