Meet 3I/Atlas, An Object From Another Solar System

The third interstellar object ever observed is in our neighborhood—for now. And, asteroid Bennu could contain dust from far-off solar systems.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

  WNYC is supported by Bear. Science is about asking questions, testing, trying again. It's not easy, but it's relentless. It evolves, and that's why science delivers. Learn more at sciencedelivers.com.

• 0:14Ira Flatow?

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• 0:30Flora Lichtman?

  Hi, I'm Flora Lichtman, and you are listening to Science Friday.

• 0:37Flora Lichtman?

  Today in the show, a space bonanza, starting with a strange visitor from another solar system.

• 0:46Speaker 03

  We put all hands on deck, basically, to make sure that we were ready to observe this object, pointing every telescope that could possibly detect it as frequently as we possibly can.

• 1:00Flora Lichtman?

  Attention Earthlings, our solar system has a visitor. Earlier this summer, astronomers discovered something odd whizzing past Jupiter, an interstellar object, an object from another solar system. Scientists named it Three Eye Atlas. It's only the third interstellar object that we have ever observed, and it's not going to be with us for long. It's due to leave our solar system by the end of the year. So the race is on to learn as much as we can about it before it leaves us behind. Here to help us get to know Atlas is Dr. Stephanie Mylum. She's an astrochemist at NASA and a project scientist for the James Webb Space Telescope. Stephanie, welcome to Science Friday.

• 1:42Speaker 03

  Thanks so much for having me.

• 1:44Flora Lichtman?

  Tell us about when you first met this object. When was it spotted?

• 1:51Speaker 03

  I first met this object in the middle of the summer, and I received a whole slew of emails the Fourth of July weekend, which nobody was checking their email, of course.

• 2:03Flora Lichtman?

  Of course.

• 2:04Speaker 03

  From my team. And saying that this new interstellar object had been discovered and we needed to activate our program on the James Webb Space Telescope to do a comprehensive study of what it's made of and hopefully disentangle some of the origins of these objects.

• 2:24Flora Lichtman?

  Okay, so you got word that there was this interstellar object and basically you were like, it's go time?

• 2:30Speaker 03

  Right, so the principal investigator of the program, Martin, is a very close colleague of mine I've been working with for goodness, 15 years now. And he was completely offline. He was hiking in the middle of the woods, I believe in Maine. So I'm trying to call him, I'm Facebook messaging him, I'm calling his wife.

• 2:57Flora Lichtman?

  You know it's desperate when you're Facebook messaging.

• 3:01Speaker 03

  And nobody could get ahold of him. So we contacted the observatory and we said that we are planning to trigger and we kind of, well, basically went behind his back and pulled the trigger on this. And so, so he comes back and we put, we put all hands on deck basically to make sure that we were ready to observe this object, pointing every telescope that could possibly detect it and look at it as frequently as we possibly can. And so we were coming down to the wire that we were going to have to observe this object with the James Webb Space Telescope now, or it's basically getting in a part of the

• 3:46Speaker 03

  orbit where we won't be able to access it with any telescopes.

• 3:50Flora Lichtman?

  Okay, so you're marshaling all these telescopes to look at it. Why is this such a big deal? I mean, I can hear in your voice it's a big deal. Why is it such a big deal?

• 3:59Speaker 03

  So this is only the third interstellar object that we are... That we know of that has come into our solar system. The first interstellar object was called Amuamua. It was one I. So I means interstellar. The number before the I is the number of objects. So one I, Amuamua, was the first interstellar object. We know Amuamua on this show. We've been following the Amuamua drama on this.

• 4:30Speaker 03

  Two I Borisov was the second one. And it was more comet looking than Amuamua was. But that was in sort of 2019. The James Webb Space Telescope had not launched. And so we used all the telescopes we possibly could on the ground. But the capability, the sensitivity and the wavelength coverage that we have with the James Webb Space Telescope, we knew was just going to open up a whole new plethora of information about these kinds of objects. And basically, it's designed to do these kinds of studies. I argue with the galaxy people all the time. I try to convince them that comets and interstellar objects is where JWST needs to focus.

• 5:15Speaker 03

  Okay, so what is Atlas? So Atlas is what we believe to be an interstellar comet. And we call it a comet because it's active, which means it's emitting gas and ice and dust. So that when you see pictures of it, so the Hubble Space Telescope has imaged it, it's fuzzy. It looks like a comet. It has a tail.

• 5:40Speaker 03

  And that means it's sublimating or the ice is actually basically vaporizing on this object as it comes closer to our star, the Sun. Tell us a little more, what's this comet made of? So we confirmed that there was definitely water, but not a whole lot compared to the amount of carbon monoxide and compared to the amount of carbon dioxide. There was so much of it. This was a huge finding for us. We've never seen so much carbon dioxide compared to water. So there's a lot of carbon dioxide. As this object comes closer to the sun,

• 6:23Speaker 03

  it's going to start sublimating more and more. And so whenever we get to observe this object again later on this year, it might change that abundance ratio in ways that we we don't know yet. So we're anxious and excited to see how that changes.

• 6:40Flora Lichtman?

  Is is what it's made of, does that relate to its journey or where it comes from?

• 6:46Speaker 03

  Yeah, we, well, that's what we're trying to find out. What we believe of small bodies, both in our solar system as well as in other planetary systems. And small bodies include everything from asteroids and meteors to comets to trans-Neptunian objects. We think these are sort of the cookie crumbs left of when planets form in a given planetary system. And so it tells us about the conditions that our solar system formed from, the chemistry, and how much of that is actually preserved versus totally cooked.

• 7:25Speaker 03

  Are we seeing, you know, burnt cookie crumbs? Are we seeing fresh chocolate chips? What what do we got? So getting access to these interstellar objects tells us something about how another planetary system formed.

• 7:40Speaker 03

  And that's what's really cool because we want to see if they look like the same cookie crumbs as our solar systems.

• 7:47Flora Lichtman?

  That's fascinating.

• 7:48Speaker 03

  Yeah, and if so, that means that that planetary system potentially had the same chemistry that formed its planets that we had here forming our planets, meaning the organic chemistry or prebiotic chemistry might be ubiquitous in other stellar systems.

• 8:07Flora Lichtman?

  And does it look like the objects in in our solar system? Or is it too soon to tell?

• 8:13Speaker 03

  That's the hard part. So the only way we see these kinds of carbon dioxide to water ratios in other planetary systems is when these objects would form way, way, way far away from their star in an area where there's hardly any exposure to radiation. So it's mostly just dust grains that are just collecting any gas in its vicinity and creating these icy grains, comets.

• 8:38Flora Lichtman?

  Yeah, it's like a peephole into, you know, another place in time, it seems like.

• 8:44Speaker 03

  Exactly.

• 8:45Flora Lichtman?

  Do we know how long this comet has been traveling for?

• 8:49Speaker 03

  Well, we don't really know how long. We expect the object to be anywhere from three to 11 billion years old, which is a considerable age. And they expect that it's actually from the thick disk of our Milky Way, so sort of closer in towards the center of our galaxy.

• 9:08Flora Lichtman?

  And when does it leave? How much more time do you have with it?

• 9:11Speaker 03

  So we don't have a lot of time, but that's okay. We're used to this. Comets come and go as well. So we're used to these sort of shorter time spans of a couple of months to really focus on the object and get as much information as we possibly can.

• 9:25Flora Lichtman?

  So I guess no sleep till 2026.

• 9:28Speaker 03

  No vacations for Martin and yeah.

• 9:34Flora Lichtman?

  Stephanie, thank you so much for joining me today.

• 9:37Speaker 03

  Thank you so much for having me and I'm really looking forward to what we figure out about this object in the future.

• 9:43Flora Lichtman?

  Dr. Stephanie Mylum, an astrochemist at NASA and a project scientist for the James Webb Space Telescope.

• 9:54Flora Lichtman?

  Up next, Bennu, the near-Earth asteroid we all know and love, also seems to have some family ties to a solar system far, far away.

• 10:05Speaker 04

  What we're talking about here is what were the baby photos like, right? And now we're starting to piece together what's happened since then to sort of adulthood, which is where we are now.

• 10:19Speaker 00

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• 12:45Flora Lichtman?

  Back in 2018, the spacecraft Osiris Rex rendezvous with Benu, and after a long journey, brought samples of dust and rock from the asteroid back to Earth. For the past two years or so, researchers have been analyzing those space pebbles, trying to tease out details about Benu's origins and what it tells us about our solar system. And it turns out that Benu may have some secrets to share from outside our solar system, too, because findings just published indicate that the samples contain bits of stardust that are older than the solar system itself. Joining me now to talk about that is Dr. Jessica Barnes, an associate professor in the Lunar and Planetary Laboratory at the University of Arizona.

• 13:30Flora Lichtman?

  Jess, welcome to Science Friday.

• 13:31Speaker 04

  Thanks for having me.

• 13:33Flora Lichtman?

  So what did you find?

• 13:34Speaker 04

  Yeah, so we looked at a range of different samples from the returned material. And some of the investigators were studying, or specifically looking for, stardust. We know from meteorites that are analogous to Benu and other carbonaceous asteroids, we know that those materials are likely to contain stardust.

• 13:56Flora Lichtman?

  And when you say stardust, are we talking about bits of exploded stars?

• 14:02Speaker 04

  Exactly. So either stars that, prior to our solar system, went supernova, so exploded, or other grains that were formed in kind of star outflows. And, believe it or not, once you know what you're looking for, they're pretty easy to spot in samples like these. They really pop out like a sore thumb. They're very, what we call isotopically anomalous. And so they look isotopically very different to anything from our solar system.

• 14:32Flora Lichtman?

  And when you say they're isotopically anomalous, is there a way to explain what that means?

• 14:37Speaker 04

  Yeah, so what we mean by that is different elements can have multiple isotopes of themselves. So the element is the same, but the number of neutrons in the nucleus is different. And so we end up with different isotopes. As an example, oxygen has three stable isotopes: oxygen-16, 17, and 18. And when we're looking at these stardust grains, or looking for them, we're really looking for ratios of...

• 15:04Speaker 04

  One of these isotopes over one of the other isotopes, an example being oxygen 18 over oxygen 16. We're looking at that ratio and that ratio is very different to anything we see in our solar system. So we literally map the sample to look for these little hotspots that indicate where we have these pre-solar materials.

• 15:26Flora Lichtman?

  Can you tell which stars they came from or which areas of the universe they came from?

• 15:32Speaker 04

  I mean, that would be amazing. At the moment, no, not really. What we can do, though, is we have observations of stars, we have models that tell us what to expect from different star types, so big, small, whether they go through a supernova event where they explode. They will encode in the dust that forms during those events, they will encode different signatures. And so what we do is we piece together what we see in the sample with what we know from those models and observations to say what types of stars they they might have come from, those grains. We can't tell you exactly which star these bits of stardust came from.

• 16:11Flora Lichtman?

  Does this revise or expand our thinking about Benu's birth?

• 16:17Speaker 04

  It contributes to it. We were expecting to see these materials in Benu. I think one of the biggest surprises was the abundance of other types of these original components. So these would be the building blocks to Benu's parent asteroid, or its ancestor, if you like. Because Benu right now is a near Earth asteroid, but it didn't always look like it does today. It was once part of a much larger object. And that object accreted or assembled from what we now know are pieces of solid material from all across our solar system. So that's one of the big surprises that we find is that some of these original components are in much higher abundances in Benu than we previously expected.

• 17:02Speaker 04

  And so we find much more or higher abundances of material that we think formed close to our sun. And also material that we think, organic material that we think formed very far out in our solar system, or even formed in interstellar space. That was one of the big key takeaways from our paper is that we think Benu's parent body formed in the outer parts of our solar system.

• 17:26Flora Lichtman?

  What a long life Bennu has had.

• 17:28Speaker 04

  Oh, yes, very complex, and we're just starting to tease out all the history. It's like going through someone's life record, right? What we're talking about here is what were the baby photos like? And now we're starting to piece together, you know, what's happened since then to sort of adulthood, which is where we are now.

• 17:47Flora Lichtman?

  Bennu baby photos, I love that. I mean, it seems like you're finding out things that you can only find out with actual samples. Do you see this as an argument for going there?

• 17:59Speaker 04

  Absolutely. Some of the things that we find, most notably earlier this year, there were reports, a new report of salts from asteroid Bennu. I mean, those types of measurements or findings can't be done on meteorite samples. Yes, we're finding here and there evidence of some of those minerals in the meteorite record, but it's not, it's been affected by terrestrial alteration because just of the nature of meteorites, they have to fall through Earth's atmosphere to be recovered. And so some of the findings we're making are only possible because we've been there. And further to that, we're able to put what we're finding in the laboratory, across multiple labs across the world, we're able to put that in context because we've been to the asteroid.

• 18:44Speaker 04

  We've seen what the asteroid itself looks like, and that really helps us to put into context our measurements.

• 18:52Flora Lichtman?

  What's next for you?

• 18:54Speaker 04

  For me, we're going to keep looking at these samples. We have a lot of work left to do. One of the things I'm most excited about the team, hopefully soon submitting and then later on showing off to the world is, you know, in the studies that have just been published, we're kind of giving you a snapshot of, you know, what did Bennu's parent body look like? What are those baby photos? What was its adolescence like? That's the aqueous or hydrothermal alteration story of how fluids were operating on the parent asteroid. And then how Bennu's surface has been affected by being in space, its exposure to cosmic rays and high energetic particles.

• 19:36Speaker 04

  Like, when did all of these things happen?

• 19:39Flora Lichtman?

  So this is like Bennu's full astronomical ancestry is what you're trying to figure out.

• 19:43Speaker 04

  Exactly. From, from its birth at the beginning of our solar system, you know, it's one of these bodies that was forming right at the beginning of our solar system, accreting and assembling from the original materials in our solar system, some materials from outside of our solar system. It's recording dynamic transport throughout the solar system to the edges where we think its parent body was forming, all the way through to, you know, material being delivered to its surface today by interaction with the solar wind. And it's, it's whole entire history, which is a history we just can't get, like on Earth, we can't even get our initial history of Earth's surface

• 20:27Speaker 04

  because the crust has been destroyed over billions of years, that initial crust. So this is a huge lifespan that we're able to look at by looking at these samples.

• 20:38Flora Lichtman?

  I am here for this intergenerational family drama. Thank you, Jess. Please come back and tell us when you find out.

• 20:45Speaker 04

  Will do. Thank you.

• 20:46Flora Lichtman?

  Dr. Jessica Barnes is an associate professor in the Lunar and Planetary Laboratory at the University of Arizona.

• 20:56Flora Lichtman?

  Thanks for listening. Don't forget to rate and review us wherever you listen. It really does help us get the word out and get the show in front of new listeners. Today's episode was produced by Rasha Aridi and Charles Bergquist. I'm Flora Lichtman. Thanks for listening.