Daniel and Kelly’s Extraordinary Universe - Was the interstellar visitor oumuamua natural or artificial?

Episode Date: October 12, 2023

Daniel and Jorge talk about the claims that 'Oumuamua might have been alien space junk.See omnystudio.com/listener for privacy information.

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I like having visitors at my university and visitors at home, sure. I like people. You like people? How about aliens? I would love if aliens sent us a message or an object or came to visit. They're welcome to have dinner at my house. What about the university? If aliens came, I would be a superstar at the university.

Wait, you would be the star or the aliens would be the star? I think the aliens would probably grab the headline more than the receiving professor. Yeah, probably. And we'd have lots of great questions for them. But then, what would you feed them for dinner if they came to your house? Probably some engineers. Ouch. Wait, you would do that.

The cooking, that's pretty dark, man. I would do a lot for alien answers, yeah. Oh, boy. Remind me never to go visit your house. You never know if you're coming for dinner or if you are dinner. Definitely not staying for dinner. cartoonist and the author of Oliver's great big universe. Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine, and I would love to get my

hands on anything alien, ideas, objects, visitors. Anything alien? That sounds a little not safe for work. Like you would put your hands on any part of the alien? I think any part of alien would be safe for work. You know, it's all in the interest of science. I guess. I guess it depends on what kind of worker you are. If you are looking to unravel the mystery, of the cosmos, then yeah, it's all up for grabs. I see. You might have to like pat some backs or something, shake some hands or tentacles, perhaps. You know, there's a lot of people on campus here who literally get their hands a lot dirtier than I ever do. I'm pretty sure everybody in the world gets their hand dirtier than a physicist.

I mean, I guess you do get chalk dust on your hands, kind of, or dry eraser dust on your fingers. We once had to unbox a thousand computers that all arrived from Dell the same day. and set them all up. But I'm not sure what kind of dirt we got on our hands that day. Yeah, yeah, that doesn't sound like a working class dust there. But anyways, welcome to our podcast. Daniel and Jorge explained the universe, a production of iHeard Radio. In which we treat the entire universe as safe for work.

We think everything about the universe is beautiful and wonderful. Nothing should be censored. And all of its secrets should be revealed to us. We would love to unravel them for ourselves, but we'd also love to get some tips from aliens about what's, going on out there in deep space. That's right. It is a beautiful universe, and we are all visitors in it, at least for the time that we are in this universe. So we like to give you a little bit of a tour of what we know

and what we found out about all the cool spots and all of the great places to see in this great cosmos. And most of the things we know about the cosmos come from seeing, come from receiving photons from outer edges of the galaxy or from other galaxies, from using that to build the mental model in our minds of how the universe is built. But sometimes we also get stuff from other parts of the universe. We get tiny little protons that might have flowed from other parts of the galaxy. We get dust from all over. Sometimes we might even get rocks and other stuff.

Yeah, well, although small rocks are okay to get here on Earth, right? From the deaths of space, big rocks are a problem. It depends a little bit on how they arrive. If they fly by and let us study them, then that's all right. But yeah, if they impact in the Pacific and cause a mile. a high tsunami, then yes, that's a problem. You like day visitors, not like overnight visitors. I mean, hey, come into orbit, right?

Then we can study you for years. That'd be awesome. Whoa, is that possible? Could like a rock come and suddenly we get a new moon? Absolutely. As we talked about on our episode about how moons are formed, some moons in the solar system were captured as they flew by. So it's certainly possible for us to catch some weird object from another solar system

and have it become part of ours. an adopted planet or moon. Wow, it's like a visitor that never leaves. It becomes part of our family, man. We don't discriminate. But could it crash into our moon? Like, if we catch it, could it maybe run into our current moon? That would be a problem, right?

That would be a problem if it, like, disintegrated the moon and that debris then rained down on the surface of the Earth. Yeah. You seem to be in kind of a cataclysmic mood today. I mean, mostly we're just looking at this stuff and learning about the universe. Well, you know, apparently if I go visit you, I might end up as dinner. So I got to, you know, think of the worst case scenario, apparently in this podcast. I got to watch out.

You do got to pay attention. That's true. But it is a wonderful universe to visit and to live in and to study and to explore. And as Daniel said, sometimes we get visitors from the far reaches of space. And recently, we got an extra special and extra rare kind of visitor. That's right. In 2017, a strange rock came through the solar system. We called it Omuamua.

It was a big surprise to everyone. and an exceptional opportunity to learn something about the rest of the galaxy to actually look at a chunk from another solar system. Wait, I feel like you're maybe pre-biasing this a little bit. How do we know it was a rock? Do we know it was a rock? I guess I'm not speaking technically when I say a rock. I just mean a chunk of something.

A chunk of stuff. Yes, it was a thing. How about that? And it has maybe one of the coolest names in astronomy, oh, muamua. What's the origin of that name, Daniel? That's right. It was discovered by a telescope in Hawaii, and so they called it Omulamua, which means messenger from afar in one of the Hawaiian languages. Whoa. It's like email, space email, or like space UPS driver. Does your email come in at 27 kilometers per second? I think it comes a little faster than that, doesn't it? How it takes me to read it, though? That's a different question.

That's right. And we talked about this object shortly after it arrived and all the controversy it stirred up because there were some. some weird things about this object. It was weirdly shaped. It was sort of glittery in a strange way. It was a surprise that we even saw it. And since then, even more controversy has been stirred up. Yeah, there's a big controversy about its origins and whether or not it's natural. As a today on the podcast, we'll be tackling the question.

Was the interstellar visitor Oumuamua natural or artificial? And by artificial, we mean alien. Oh, I thought you just meant like, not organic. Like not good to eat? Yeah, like it has aspartame or something. Yeah, you got to cut down on your artificial space junk, man. It's not good for your diet. Yeah, yeah.

Come to my house, we serve you purely organic engineers. Oh, my goodness. Free range. Free range. Free range. You seem to be making that joke a little too much. But this is a really fun question because getting a chunk of stuff from another solar system is a way to see what's out there, right?

It's like a core sample of the rest of the universe, something we very rarely get to see because we're on this little island of the solar system, this little patch of land that we've been able to explore with our probes. Well, it might be a core sample of perhaps alien technology or something, right? That is the big question about Oumuua. Was it natural? Is it like just a rock that's naturally floating out there in space? or could it be some sort of device or a spaceship or something made by an alien civilization?

That's the big question. And when this thing came to the solar system, a bunch of astronomers looked at it and studied it and debated it, of course. And one astronomer in particular has made a lot of hay about it. Avi Loeb, a professor at Harvard, wrote a book called Extraterrestrial, the first sign of intelligent life. Whoa. This, of course, made a big splash and was a bestseller and got a lot of people talking. The sort of mainstream community astronomer didn't take it very seriously. And Professor Lopez complained somewhat that his arguments have not been addressed by sort of mainstream astronomy.

You mean he claimed that the Omoa was a sign that there are aliens out there. And now he's saying that people aren't taking him seriously. Yeah, that's exactly right. Well, as usual, we were wondering how many of our listeners out there had heard of Omuamua and had thought about whether it was natural or artificial. So I'm actually visiting UC Riverside this week. so I took the opportunity to walk around campus here at Uzi Riverside and asked people if they had heard of Omuamua

and if they thought it was natural or artificial. So think about it for a second. Have you heard of Oumuua Mua before? And do you think it could be a sign of aliens? Here's what people had to say. All right. So do you think Omuamua was natural or artificial? Natural.

Why is that? I don't know. Have you heard of the object Omuamua, the interstellar comet that came through the solar system five years ago no no okay great do you have an opinion about whether it was a natural object like a comet from another solar system or an artificial object like an alien craft maybe natural maybe natural okay great oh no what's that you never heard about it is this object that came through our solar system no okay great do you think it's more likely to be a natural object or

alien space junk more like a natural object natural object natural object how come Because there's no evidence now we find an alien, right? So it's more like a natural object. How did you do your opinion? Yeah, more or less the same natural object seems more likely. Absolutely a natural object. All right, first of all, not a lot of name recognition, it seems. At least not in Riverside.

I was even walking around the physics department at Riverside, hoping to get people who had thought about this stuff. Maybe you weren't pronouncing it right. Probably not, yeah. And you were attaching it to a dinner invitation, which is a problem now that you have a reputation. I'm staying away from the engineering buildings on every campus from now on. Yeah, it sounds like the engineers should stay away from you. But yeah, not a lot of recognition.

Although some people have heard of it and they seem to think it's natural. They do seem to think it's natural. I mean, it's a fascinating object. And there are some things about it that are weird that can teach us about like what's out there in the universe. I think the evidence for it being actually alien is quite a reach. that kind of thing you might put in a best-selling book that you want to sell a lot of copies of but not something that would really stand up to peer review. I see.

I mean, if a physics professor writes a book about aliens, that's obviously just a big money grab, right? I think it depends on the claims you put in that book. And so on the episode today, we wanted to dig deep into what's going on with Omuamua. Is it natural? Is it artificial? What do we know about it? What can we say? Well, let's dig into it then.

Daniel, what is this object and when was it first spotted? So it's definitely from another solar system. We spotted it first on October 18th, 2017 by the Pan Stars Telescope. This is a really awesome telescope. It's in Hawaii. It's actually two of them. Each of them are almost two meters in diameter. And they're on the summit of Haleakala on the island of Maui.

And their job is basically to look for stuff that might hit the Earth. They're taking pictures of the night sky all the time. And they're looking for changes. It's looking for stuff that's moving. It's part of this search for near-Earth objects to see whether there are things out there that are moving that might, of course, hit the Earth. Well, that's pretty cool.

It's like a watch guard almost for the entire planet. It's a full-time. It's doing that full-time. It's doing that full-time. It's pretty awesome. This is sort of a newer effort by NASA. It really was kicked off after Comets Shoemaker Levy in the 90s when we saw, wow, things in the solar system

really can impact comets and cause huge fireballs. We better put some more money on this. So in the last 20 or 30 years, NASA and some international partners have really dedicated some resources to looking for near-earth objects. And they see a lot of them and they've cataloged all the big ones and we know mostly what's out there. But sometimes they see something strange. And in 2017, they saw this object moving in a way that they could tell it was not coming from inside of our solar system. Interesting.

So it's just out there looking at this night sky all the time and it records if something changes. Now, how did they know that it was coming from outside the solar system? Because of where he was coming from, it entered from above the plane of the solar system. The whole solar system is basically flat. Everything's orbiting in a plane that's determined by the north-south pole of the sun. But this thing was sort of coming in from above the plane from the direction of the constellation Lira and passed really close to the sun, actually within the orbit of Mercury and then out the other side. I guess the question is, you know, if you look at the night sky and you see a streak, it's kind of hard to tell in 3D where it is or where it's going or, you know, in exactly what direction.

just because you're getting just a 2D view of it, how did they figure out where in the solar system it was going? You can reconstruct its 3D trajectory. First of all, we have two of these cameras. We have a slightly binocular view. But then also as it gets brighter and dimmer, you can figure out sort of its radial velocity. And they can measure its velocity across our view

just by seeing how the points of light are moving. So they can end up with a 3D trajectory and then backtrack and say, where could this thing have come from in order to give us this path? No, I think you said that they saw a streak, not just the little point flying through space. Yeah, most of the stuff in the solar system is moving, and it's moving fast, but it's not moving that fast. So on this camera, it usually just registers as a pixel.

Like light from the sun hits it, bounces off, and it comes into the telescope in Hawaii, and it makes a bright pixel. We say, okay, there's something there. But this was moving so fast, 26 kilometers per second relative to our solar system that actually made a streak. It was like multiple pixels across. Whoa. And so, and I guess they didn't just see it once. They could track this thing, right? They could track this thing, exactly.

but by the time they saw it, it was already on its way out of the solar system. Like it made its closest approach to the sun and then came closer and closer to the earth. And by the time we saw it on the earth, it was already sort of like on its way out of the solar system. So then we could just sort of like watch it from behind as it left. And then it got dimmer and dimmer and dimmer. So we only had a few weeks to gather data about this thing. Well, wait, wait. Why didn't we see it before?

We saw it when it came close to the earth. And that's the easiest time to see it. Before that, it was either like coming from the sun, which makes it impossible. to see it, or it was too dark. The object itself was too dark, because I guess it wasn't glowing by itself. It was just reflecting light. Exactly. You need to be sort of lucky with the arrangement of the sun and the object and the earth to even

see these things, right? Because you need light from the sun to hit it and then bounce off and hit the earth. As you say, it's not glowing. It doesn't have fusion. It's just a big chunk of stuff. It has to reflect light to us from the sun. And lots of spots on its trajectory to be basically invisible. Well, scientists notice some weird things about it that make them think that, hmm, I wonder

if this thing is natural or of alien origin. So let's dig into what those odd things about it were and talk about whether it is a message from aliens. But first, let's take a quick break. Imagine that you're on an airplane and all of a sudden you hear this. Attention passengers. The pilot is having an emergency

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Apple Podcasts, or wherever you get your podcast. All right, we're talking about visitors. to our solar system in 2017, we got one that we seemed a little fishy, called Omuamua. It definitely was a lot of fun to look at and to think about. All right. So we saw this in our telescopes looking for asteroids out there in space. And there was something a little bit different about its trajectory. It seemed to be coming definitely from outside the solar system.

And scientists think at least at the time they thought or they considered the possibility that it might be from an alien civilization or something. What were some of the things that made people think, hmm, this is maybe just an asteroid? So first of all, it seemed to have a weird shape. Like a lot of the asteroids in our solar system are mostly spherical, like they're round-ish. This thing either was really, really long and thin. A lot of the artistic depictions of it draw it sort of like a cigar,

or it was sort of flat like a pancake. So that's thing number one that makes it kind of weird. But could we actually see its shape or isn't it so far away? You basically just see a dot? Yeah, we can't see its shape directly. You're right. But we could deduce its shape by how it's spinning and how its brightness changes. So if it's not a sphere, then as it spins, you might reflect more or less light off the larger or smaller surfaces that it's presenting.

So they have to deduce its shape from how it's spinning, which is why we're not sure if it's a cigar or a pancake. We just know it's not very spherical. Wait, so if it was spherical, then it would just look like a constant dot of light in the sky, right? But this wasn't a constant dot of light. It was not a constant dot of light, exactly. What was it? The light varied really dramatically, like by factors of 10, which made them think that maybe it was really long and thin. And sometimes you were seeing the long side of it.

And sometimes it was really narrow and you were just reflecting light off the tip. But definitely was not a sphere because otherwise, as you say, it would give you a constant signal. So it was like blinking or just kind of fading in and out? It was more fading in and out. Never totally disappear. If you look at the light curve, you see it varies over a very wide range. In what time scale? Like every hour, every second?

More like hours, exactly. We only have a few weeks of data of this thing, but it was spinning pretty fast. I think it was also tumbling, like it wasn't only spinning along one axis. It was like spinning in two different ways at the same time. But at least we think it was spinning, right? We don't actually know because you just see a pixel of light, right? Yeah, exactly. This is all reconstruction.

But there was a bunch of stuff about it which seemed kind of weird. There was the shape. There was how it moved. It seemed to move in a way that wasn't just gravity. It seemed like it got a little boost as it was leased. in the solar system, which made people think, like, ooh, maybe it's an alien spaceship or maybe it's a light sail or these things that like gathers photons from stars to pick up acceleration. So that was Avi Loeb's suggestion that this might be a discarded alien light sail that fell

through our solar system. And it's also kind of rare to get stuff from that direction, right? Like we don't get a lot of comets or asteroids from our asteroid build. Well, we don't know how rare it is, right? We sort of turned on this eyeball to the universe fairly recently, and seeing one sort of new either means that we're very, very lucky, or it means that there may be more common than initial calculations suggest. It could be that space is filled with chunks, little bits from other solar systems, and it's not that unusual to see one. All right, there were some weird things about it that made people that wonder about this, but one professor in particular sort of seemed to have gone all in on it. That's right.

Jason Wright, a professor at Penn State, wrote a. detailed blog post, responding point by point to all the claims made in Avi Loeb's book. And I thought it would be a good idea to chat with him about all these ideas and what he thought Omoomua might actually have been. Okay, so then just to be clear, you spoke to Jason Wright, who's arguing against the book written by Loeb, who argued that Omoomua was of not just extraterrestrial origin, which it is, because it's not from Earth, but that it's a sign of intelligent life. Yeah, that's right.

Loeb is making some pretty outlandish claims in his book, and he's also complaining that nobody's taking him seriously. So Jason Wright decided to take it seriously and address all the claims and say what we know and what we don't know. And of course, nobody knows for sure what this thing was, but we should be careful about the claims we make. All right. Well, here's Daniel's interview with Professor Jason Wright. Great, so then it's my pleasure to introduce to the podcast, Professor Jason Wright. He's professor of astronomy and astrophysics at Penn State. He's a member of the Center for Exoplanets and Habitable Worlds, and amazingly, he's the director of the Penn State Extraterrestrial Intelligence Center, which sounds like a lot of fun. Jason, welcome to the podcast. Thanks. Good to be here. As director of the Extraterrestrial Intelligence Center, do you get first access to the alien bodies to interrogate them and ask them questions?

No, no. Thank goodness. That's definitely outside the purview of what we do here at the P. SETI Center. So, yeah, I can't have no information on that score for you. All right. Well, I do want to ask you questions about things you're actually an expert in. And I was very excited to talk to you because this blog post you wrote where you did a point-by-point analysis of the claims made in Avilob's book about the possible extraterrestrial or alien nature of Omuamua. So I'd love to ask you first to briefly run down. What are the evidence for the anomalies or the sort of five categories he lays out and then dig into them with you? Yeah. So Oumu was definitely interstellar. We know that for sure. And it was definitely very strange. But when we say it's strange, what we mean is we kind of had a sense for roughly what comets look like in general. And we thought when we saw one come from interstellar space, it would more or less look like the comets that orbit the sun. And the main reason is that the comets that orbit the sun that come from the orc cloud very far out. They're basically in interstellar space. There's not a big difference between the space and the

cloud in between the stars. And so we didn't expect it to be so different from typical comets. There's a big caveat with that, though, which is that Omuamua was extremely small. And we don't generally detect comets that small in the solar system, just because being so small, they reflect hardly any light and they're very hard to see. We have very few examples of any objects in the solar system that small orbiting the sun, which means we don't actually have a basis to compare to. So when we say it's strange, it's really strange compared to expectations, not necessarily strange with respect to ordinary comets in the solar system of that size. So the first thing that was really strange about it is that its brightness varied a lot.

And that has been interpreted to mean that it must not be round, which is perfectly reasonable for something of that size. You have to be quite large, like a large asteroid, to be round. But it was really extreme. I mean, the brightness variations indicated that the axis ratios had to be something like 5 to 1 or maybe even as high as 10 to 1. And the shape was kind of unclear. We say this because if it were just that part of the surface was dark and part of it was highly reflective, that can only change the brightness so much as it rotates.

And the brightness variations are highly irregular. So that suggests it's either like flat like a pancake or long like a cigar and that it's tumbling doing this kind of uncontrolled rotation. And sometimes we see the thin end of Omuamua, and that's when it's hardly reflecting any light towards us, and that's when it gets very dark. So when you say brightness, you're not talking about this thing glowing, obviously, right? It's reflecting light from the sun. That's right. All objects are going to reflect light from the sun. And if it's shaped like a pancake, and as it's tumbling, then when we see the whole pancake sort of face on, then it's reflecting a lot more sunlight, and it'll appear bright. But then if we see it,

it edge on will hardly see any sunlight reflected. We can try to infer the shape, but it's a really inexact science. It's an unconstrained problem. And so it's possible at something like a 10 to one long cigar, like in a lot of the imagery you might have seen online. There was an artist's picture of it being almost needle-like. But I think most planetary scientists think it's probably more like a flat pancake, maybe six times wider than it is thick. If it were shaped like a round rock then a sphere, then as the sphere spins, we always see the same size. So the only way that the brightness would vary is if part of it was reflective and part of it was not. Now, that's normal. Things have dark areas and bright areas on them. But we would see it change in exactly the

same pattern, every rotation. And there's only so much variation that you can get from that sort of surface brightness changing. When you see this kind of very irregular, very strong brightness variations, that's most naturally explained by a strange shape. So imagine you had like a piece of charcoal and half of it was dipped in white paint. So, you know, if you illuminated it, it looked like black and white, but it was perfectly spherical and it's spinning. You're saying that we would see a regular variation in the brightness. We would see it bright and dark and bright and dark.

Right. You see almost a sinusoidal variation. And only if you happen to be at that special orientation that you got it completely white or completely black once a rotation, would those brightness variations be, you know, 10 to 1 or something extremely strong? And so you're saying that what we saw were huge variations in the brightness and the pattern was kind of irregular, meaning that we're not like seeing the same side of it over and over? Is that what you mean by tumbling? That is what I mean by tumbling. So when something just spins, then every single rotation, it comes back to the same orientation, like the earth spinning

or something like that. But if you take an irregularly shaped object, in the classic example, here is something like a chalkboard eraser or a whiteboard eraser. If you try to spin it lengthwise, you'll find it won't uniformly spin. It'll start doing this very strange, irregular, almost kind of random flipping in the air in all these different directions. And that's called tumbling. And when that happens, you do not see this regular brightness variation. And so Omuamua is definitely tumbling. And what that means is it's very hard to model because it's almost a random variation. And that's why it's so frustratingly difficult to figure out what its actual shape is. So does tumbling just mean spinning on more than one axis at the same time?

That's right. That's a good way of thinking about it. Basically, the axis of rotation sort of changes with respect to the shape of the object. And it's not regular. This object is so small and so far away that it's just a point of light. And so everything about it, we have to infer from that light. We can watch it change its brightness. And so try and figure out what shapes would do that. we can also look at how bright it is at different wavelengths,

and that helps us infer what the surface might be made of based on what light gets reflected and what light gets absorbed. So we're looking at a single pixel in a telescope and just watching you get darker and brighter. And from that, we have this crazy artist impression with all these like crags and nooks and all these vinkles on it. That's exactly right. That's crazy artists.

It really helps to imagine yourself there. It really helps give you physical intuition for what, going on. And so I think it's a really valuable exercise for us to imagine what these things might look like. But we always have to bring with that the caveat that we have filled in way more details than we actually know. And sometimes that can be frustrating when communicating to the public, trying to convey we're sure about this. But these other details I'm showing you are just complete fiction and could easily be wrong, like the crags, right, the little shapes on that long black cigar shape. Especially in exoplanet science, I feel like they're often showing us

essentially fantasy data. You know, this is what an artist thinks this planet looks like, when really the image we have is a single pixel. Every planet around another star we've ever detected. We've only gotten, you know, information from just a point. Sometimes that point is just the star, and we can infer it's there, and in a few cases we can actually image the planet. But by that, we just mean we see the star in one part of the image

and this little dot that's the planet and another part of the image. Exoplanets have a really special place in the imagination of the world because unlike, you know, a nebula or a supernova or a gamma ray burst, a planet feels like a place, you know, that we could in principle visit and in science fiction where, you know, we do go and visit. And so the reason people are interested is it's like what would it be like if you were there. You want to imagine what it's like if you were there. It's one of the things that made planetary exploration so compelling when we started to visit Venus and Mars and Jupiter and Saturn is that we actually sent robots.

there. And we will even say, we've been to Jupiter, right? Okay, we have not been to Jupiter. But we've got great pictures that make us feel like we've been to Jupiter. And so that's why you get these like NASA Exoplanet Travel Bureau posters, right, where they're like advertising, come to this planet and they, you know, all the cool stuff and these very retro style. Those are really popular and those are really fun for that reason. And it makes exoplanets a lot of fun to study. All right, but we're not selling Omuamua as a tourist destination. We wanted to understand the shape of it because we had sort of a deeper question, right? Which was like, is this thing weird or unusual? And so you were saying that the initial idea was that it was long and thin, sort of like

10 times longer than it is thin. But now we have another idea that maybe it's flat like a pancake. How can both of those be consistent with the light variation? Right. And I think that's because it's tumbling. And so we don't actually know what its orientation was because it's kind of this random orientation. And the data are really sparse. You know, we don't get to, point the Hubble Space telescope at it constantly and follow its brightness all the time. Only the largest telescopes because it was so small could make accurate brightness measurements. On the ground, you can only do it during the day and when you're allowed to use the telescope. So you end up with this very sparse data set where you only know its brightness.

You know, for a few times, maybe you get a bunch of measurements over the course of a couple days and then nothing for a month. And so you're trying to infer the shape from very limited information. And it just turns out there are multiple different shapes that plausibly could do that, depending on exactly how it's tumbling, which is random and can't be predicted. And so then the shape is important to this larger question of like, what is it? Because the argument is made that like long, thin things are weird and unusual and therefore might be alien.

Is that the idea? So obvious point was that if you look at the most extreme models that fit the data, Some of them said the access ratio was 10 to 1 to 1. And, you know, we could also fit it with something only 5 to 1 to 1, and we could also fit it with pancakes. But that was like the strangest and most extreme value that people published as a possibility. And he really grabbed onto that. And he argued that that's far beyond the access ratio that we see in any object in the solar system.

And so that automatically puts it in this, you know, that looks unnatural, that looks weird, that's something else kind of category. And so that's when all these caveats come in. This is a very small object. We have very few examples of such small objects. But interestingly, the objects in the solar system that do have extreme access ratio, it's like five to five to one or something, are also among the very smallest things in the solar system. So it's very possible that very small objects often have these kinds of access ratio.

And, you know, it's not like we can't, you know, come up with reasons why that might be. if you take a bar of soap and a bar of soap sitting there in your shower every time you take a shower the soap loses soap and it kind of loses soap from all sides it doesn't just become a smaller rectangular prism with every shower it becomes flatter and flatter and thinner and thinner until it's just like you know this little wafer and so whenever you erode something evenly on all sides that's sort of naturally what happens if you start kind of you know pancake-shaped you'll end up extremely pancake-shaped. So if this object is made of ices of some sort,

some very, you know, cold stuff like water ice or carbon dioxide ice or nitrogen ice or something like that, then as that ice sublimates away, it would be very natural for it to end up having an access ratio like that. That makes sense. That could be what's going on, but we have access to so few objects of this size. It's just a story, but it's plausible.

It makes sense. The strangest thing about it is probably its orbit. So we caught it pretty late in the game. It had already come in from interstellar space. It had whipped around the sun. It was on its way out when it was discovered. It happened to come very close to Earth then. And then as it left the solar system, because it was the first time we'd seen such an object,

it was tracked pretty carefully by the Hubble Space Telescope and other telescopes on Earth. And as we tracked its orbit, it did not follow the orbit you would expect from just, Newtonian gravity, the orbits that the planets follow around the sun. It seemed to be getting some sort of a push away from the sun that made it slow down less than you would think on its way out. So that's called a non-gravitational acceleration. It's not usually seen in large objects like planets because what could push a planet around other than gravity. Comets, on the other hand, tend to have this a lot. And that's because as they get close to the sun, the ice is on their surfaces melt, they come off in these big jets, and then from the rocket effect of that gas escaping

the surface of the comet, the comet will react and move the other way. And so comets sort of propel themselves by all of that gas coming off of their surface. So just so that I understand, you're saying if you dropped like an inner rock, rock that didn't have any rockets, wasn't the spaceship, had no way to apply a force, we could predict very precisely how it would move in the sun, the gravitational field. If it's a big enough rock that other things can't push it around, That's right. It's going to follow a very well-defined curve. If you take an astronomy class, you know, it's got to be a circle, an ellipse, or a parabola or hyperbola. These are the conic sections. They're the solutions to Newton's equations for two objects that are gravitationally attracted to each other.

And so one way to find out if something is an alien ship, for example, is to see, is it moving under thrust? Basically, is it firing some engines? Like the space shuttle or our ships don't obviously move just in gravitational orbits, right? Right. There's actually two reasons you would expect an artificial object to do this. Interestingly, one of the first claims of an alien spaceship in the solar system was under very similar reasoning. It was by Yosef Schlofsky, who was a Soviet astronomer, who co-wrote a book with Carl Sagan on Life in the Universe. And in that book, he described the difficulties in getting the orbit of Phobos, the moon of Mars. People were trying to predict where the moon would be, and it just wouldn't be where it was supposed to be, and trying to figure out what the problem was.

Now, the problem was probably just bad data at the time. It was a very faint object to see back then. But one possibility, Schlafsky pointed out, was that it was hollow. Now, why would being hollow mean it doesn't follow a normal lunar orbit? The reason is that the sun's radiation actually carries with it a little bit of momentum. When the solar photons hit you, they're kind of gently nudging you away from the sun. is an incredibly weak effect. You'll never notice just standing there. But if you have a light enough object, like a pebble orbiting the sun, this actually matters. And it will make that pebbles

orbit around the sun a little different than you'd otherwise expect. And so Shklovsky's suggestion was that despite being, you know, very large, many kilometers across, that Phobos was actually hollow. And so that photon pressure from the sun was enough because it hardly weighed anything because it wasn't solid rock to alter its orbit. This didn't really go anywhere. I think in the end they figured out it really is just a rock, but it was an early example of this. And so the same thing could be happening, Avi argues, to Omuamua,

that if it's actually not a big lump of rock, but it's very thin or it's hollow or something like that, then the pressure from the solar photons will push it away from the sun much the way that we saw it getting pushed away from the sun. So the argument was, you know, it could be a comet, and that's what we're seeing, or Avi says it could be highly reflective and hardly weigh anything, and that would do it too. Basically, if it's an alien light sail. Right. So Avi works on a project called Breakthrough Star Shot, and the idea is to build spacecraft that can travel interstellar distances to actually go and visit a nearby star system.

And the method that Breakthrough Star Shot proposes is to build a light sail. So you have a very small spacecraft and you attach it to a highly reflective sail, and then you shoot a powerful laser at the sail, and that powerful laser will then, through radiation pressure, accelerate it to extremely high speeds if it's low enough mass. So his suggestion was that this might be the method that aliens around the galaxy use to propel their spacecraft, and then once you get going, you know, those sails, perhaps they get discarded or perhaps something hits them and they fall off. But his argument is that the galaxy could be littered with the detritus of all of these launches. And if that's the case, then we might expect now and then one of these sails to come, you know, through the solar system. And you'll be able to tell it's a sail because when light hits it, it pushes it very easily. It has a very large surface area for its mass. And the whole, you know, it was designed so that photons could push it around.

And then wouldn't you be able to predict very specifically how that would move through our solar system? Like it should get a bigger push when it's closer. to the sun and a smaller push when it's further away? Did Oumuua follow that kind of trajectory? Again, we only caught it on the way out, not on the way in, so we don't have the complete orbit for Oumuuma. But from what we could tell, the acceleration it felt, the non-gravitational acceleration,

was entirely away from the sun. So that is consistent with solar photons pushing on it. It's also consistent with a comet. Now, there was just a little while ago a study that looked at what if you had a sail, what, you know, would it really all be just pushing away from the sun? So we don't know, you know, how a sail would fold, what it would be made of, you know, what degrees of freedom it has, what its shape would be, you know, alien solar sails, who knows? So they just started with a simple toy model to see, you know, roughly what we might expect. So they just said, okay, it's a rigid sheet.

Let's just take a rigid sheet, let it get pushed by sunlight, throw it to the sun, and see what happens to it. Oh, and they made it tumble. They didn't have it always present the same face to the sun because we know Ouluamua was tumbling. And what they found was that most of the time, the sheet is not directly pointed at the sun, which means when the light reflects off of it, the push is not directly away from the sun,

but off to the side at some angle, depending on how it's oriented. And so as it flutters, as it tumbles, the push it receives from the sun will keep changing directions, but it will often be lateral. It's not entirely a way. And they found that for their model anyway, that was inconsistent with the orbit of Omuamua. And so you can't rule out any possible solar sail or whatnot.

But they said if it's really thin and tumbling and its radiation pressure, you probably would have seen lateral acceleration, so it's probably not a light sail. So it would have zigzagged more if it was a light sail? Something like that. I don't know the details about whether it would have a preferential direction to the side. It probably depends on exactly how it's being pushed. Now, Avi's big argument for why it needed to be radiation pressure and not commentary outgassing is that Amuamua never showed a coma.

Most comets, when they get close to the sun, they start evaporating their ices, and that forms a cloud that reflects a lot of sunlight, and they get bright, and then some of that cloud goes out of the back, and that's their tail. Umuamua never showed evidence of a coma. In addition, we looked carefully to see if we could detect any gases around it, and the spitzer space telescope couldn't find any. And so to Avi, this is pretty conclusive that it's not a comet, that it was not outgassing, and it must have been reflection. And if it's reflection, it must have been low mass, which means it must be artificial. Now, a lot of planetary scientists

objected to this. It could be made of a strange kind of ice. After all, this is an interstellar comet. It's the first one we've seen. Who knows, you know, what's common out there. So my colleague Steve Desh has proposed that it is made of nitrogen ice. We know nitrogen ice exists. The surface of Pluto has big regions that's just nitrogen ice. And here, I mean, if you get, you know, the air you're breathing cold enough, you know, first you'll get the liquid nitrogen. And then if you get that liquid nitrogen, much, much colder, it'll turn solid. And that's what I'm talking about.

This is so cold that it's solid nitrogen ice. And that actually fits the data very well if it's a chunk of nitrogen ice. So we're talking about a chunk of nitrogen ice coming through the solar system, and then the sun is heating it up and the nitrogen boils off. that's effectively like a little rocket. So the comet is getting non-gravitational acceleration because it's pushing out all those nitrogen atoms, and that's effectively how a rocket works. So it's like a natural rocket on the back of a comet. That's what you're saying? That's exactly right. And that's how all comets work. The question was, with this apparent comment,

why didn't we see all of this dust and gas around it? And so the answer needs to be, it's a very clean comet. It doesn't have a lot of dust to blow off. And the gas must be something we didn't look for like nitrogen. There's another suggestion that it might be a hydrogen ice, which would be pretty exotic. We don't know that hydrogen ice can even exist in space, but it's a possibility, and that might also fit the data pretty well. So these are kind of out there explanations. We haven't seen something like that in the solar system, or at least we haven't obviously seen something like that in the solar system. There are so-called dark comets. These are clearly comets. They're clearly outgassing because we see these non-gravitational accelerations, but they don't have

Comey. They don't have tails, and it's hard to find the gas around them. And so it could just be that these dark comets weren't really recognized as being important and interesting and characteristic of the first thing we'd have come through the solar system. So you're saying there are other examples in our solar system of non-gravitational acceleration without obvious outgassing with no tail. So this kind of thing we've seen it before. Yes. Yes. Yes. We've discovered many more of them recently. I think Oumuua has spurred a lot of interest in them. But yes, there are examples like that.

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Now it's a personal mission. I wouldn't have to go to any more funerals, you know. I got blown up on a React mission. I ended up having amputation below the knee of my right leg. and a traumatic brain injury because I landed on my head. Welcome to Season 2 of the Good Stuff. Listen to the Good Stuff podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. A foot washed up a shoe with some bones in it.

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You didn't have to audition? No, I didn't audition. I haven't auditioned in, like, over 25 years. Oh, wow. That's a real G-T. talk right there. Oh, yeah. We've got some of the biggest actors, musicians, content creators, and culture shifters

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But the whole pretending and code, you know, it takes a toll on you. Listen to the new season of Grasas Has Come Again as part of My Cultura Podcast Network on the IHart Radio app, Apple Podcasts, or wherever you get your podcast. That's sort of my other question is one line. of argument you're making is this thing is small and weird and it might just seem weird because we haven't seen the small stuff in our solar system and so when we compare it to the big stuff it seems weird but then why did we see oh muamua if the small stuff in our solar system is hard for us to see why did we even see oh muamua well one thing it's very hard to see very small objects

so it's not surprising it took a long time to find something that's small secondly it's got to get very close to earth things orbiting the sun sort of have preferential orbits. There are certain places we find them. And they tend not to come very close to Earth because anything that comes close to Earth will feel Earth's gravity and get perturbed and then it won't be in that orbit anymore. And after five billion years, you know, all those things will have been cleared out. So you need something on a strange temporary orbit that's not going to last long that comes by, gets deflected by the Earth and it's gone. So interstellar objects don't care about that. They just go where they go. If they get perturbed, they get perturbed. Because,

you know, they're not going to be around for long anyway. doesn't matter. So it's not that surprising that we don't see these very small objects super close to Earth if they're orbiting the sun. But I think the real answer is just they're hard to find. You've got to get incredibly lucky. And for the reason I just said, you're more likely to get lucky apparently with these interstellar ones. And for Amuamuah, there's a detail that I never understood, which relates specifically to that, which is that we only saw it after it was moving away from us. Why didn't we see it when it was closer to us? Isn't that when it would have been easiest? No, no, we did see it when it was closest to the Earth, or not long

after it was closest to the Earth. The in and out of the solar system has to do with where it was with respect to the Sun. So as it approached the Sun, it was pretty far away from Earth. I don't remember the exact orbit. It may have even been in the same direction as the Sun from Earth's perspective, in which case you'd have no hope to see it during the day. And it was only on its way out that it was both close to the Earth and visible at night. And then we got very lucky with its discovery in the PanStars survey. So its closest approach to the sun was before it came by the Earth,

which is when we spotted it. So one lesson from Omulamua might be, hey, there's a bunch of interesting tiny stuff in our solar system. We should understand it better so that when tiny stuff from other solar systems comes through, we have more context. Is that the message?

I think that's very important. I think all of this discussion on Amulamua has really made these objects perhaps seem more interesting and spurred a lot of interest in them because it doesn't seem right that the very first interstellar object we see would be something that has no analogs in our own solar system. And we're very interested in these interstellar objects because we have very few examples of material that's not from our own solar

system. In principle, these things probably formed when the planets in other stellar systems were forming. And those are hard to study because they're very far away. But if little bits of stuff gets flung out of those and comes here to Earth and just, you know, sort of lands in our lap. That's a great way to study these other systems. Not that we can tell exactly which system it came from. But, you know, in principle, just in general, to see what other fragments of planets from other solar systems might be like is super interesting. So another topic that people mentioned a lot when Omu Mua was discovered was that it seemed

surprising that we found one so quickly. As soon as we turned on this telescope, very shortly afterwards, we found this weird object. objects which people expected to be very, very rare. I remember reading this argument that for us to see one so quickly, basically every star in the Milky Way would have to have and eject like 10 to 15 objects during its lifetime for us to so quickly see one. What's the understanding now is now do we understand that wow, really stars are creating lots of these stellar debris and flinging around the solar system? So first of all, we didn't detect Oumuua as soon as possible. The PanStar survey has been going on for over 10 years. It's just very hard.

hard to detect something this small. You have to really get lucky that you just happen to catch it when it's close to Earth. So it's not that we found one as soon as we started looking. Rather, when people calculated how many of these things they expected there to be in the galaxy, it was thought that these surveys wouldn't get lucky enough to see one. But remember, these guesses are based on our understanding of planet formation for which we've never had a physical sample. A lot of these models are just trying to understand what's going on inside of these protoplanetary nebula where you can't really see what's going on, especially objects of this size. Those estimates really strongly depend on how many things there are at different sizes. So generally, you know,

there's going to be a lot of big rocks orbiting a star and then more medium rocks and then lots and lots of little tiny ones. And the total number of rocks strongly depends on how sort of steep that relationship is. So for every one rock that's a kilometer across, how many are 100 meters across? Is it 10 times as many? Is it 20 times as many? Is it 200 times as many? And so on all the way down to the size of Omuamua. And that's really unknown. We just don't know how many little objects there should be. So the number that get ejected per star required for us to have seen one is a little on the high end of what we expected. But it's not completely outrageous. and that number also depends on how reflective and shiny they are.

This object seems to be extremely reflective, like it's pure ice. That makes the smaller ones much easier to detect than those previous estimates would have guessed. I see. So even just by getting one or two objects, we can infer something about the broader population of zillions and zillions of objects. That's really fascinating. Right. Yeah.

In order for us to have seen one by now, there must have been a lot. And I should point out, we now have two. There's also common Borisov. So shortly after a Muamua, a second comet, interstellar comet, was discovered. And it actually looks a lot like we expected interstellar comets to look. So I don't know, whether that makes Omuamua weirder or more ordinary. It kind of goes both ways. It means that, yes, it's not weird that we found a muamua, we found Borosov too.

On the other hand, Borosov doesn't look like a muamu. So there's at least two different kinds of these comets, apparently. And in the context of the question of like, is this a natural object or an alien object, it's not implausible, you're saying, that there could be enormous numbers of these bits and pieces of other solar systems floating around, rainy down on us occasionally. It's in fact quite expected. Like, we know that the planet formation process kicks out the building blocks of planets, little asteroids, little comets. We know that that happens. And we still see that in the solar system because Jupiter knocked a lot of these things during planet formation out of the solar system.

We know that because some small fraction of those things that kicked out of the solar system didn't quite make it. They got far from the sun. They slowed down, slow down from the sun's gravity, and the sun just barely held on to them. And now they orbit the sun in the orc cloud and occasionally come and visit us as long period comments. And so, you know, you can tell from the number of comets that come in how many didn't get fully ejected. And from that, tried to extrapolate to how many must have successfully been ejected. And it's a lot. But in comparison, for us to see, for example, a piece of alien junk,

it would mean that the galaxy has to be, like, overflowing with alien junk, right? Like, if we're seeing a light sale, that would suggest that there are, like, 10 to the 15 alien junk light sails out there as well. So, Audi's hypothesis is that it is very common to launch large numbers of spacecraft with light sails and that the galaxy is just filled with the litter from all of these space launches all the time. So, yeah, you have to imagine. in sort of a pan-galactic technology that's sending ships from star to star all the time. Wow. Well, that is a large hypothesis to consider. Let's also talk about the velocity of this

object. I understand that it had sort of unusual or unexpected speed as it entered the solar system. Right. So there's a big caveat, which is that we don't know how it entered the solar system because that depends on the amount of non-gravitational acceleration that it experienced and it depends on how much mass it lost so under the ice models we i think we favor most it lost something like 90% of its mass as it warmed up and got near the sun which means it experienced a lot of non-gravitational acceleration before we even saw it but we don't really know how much that big error bars on that. So it could have been a huge bar of soap as it approached the solar system and then we just saw a little sliver after it got melted by the sun. That's exactly right. That

could very easily be what happened. And with big uncertainties like that, it's hard to extrapolate backwards and get an accurate reading on how it came in. Now, if we do our best and say, you know, where did it probably come from, then the direction it came from is kind of interesting. It's basically exactly the direction the sun is headed through the galaxy. And the speed it came in at is basically exactly the speed of the sun through the galaxy, which means it was basically from the galaxy's perspective sitting still. It wasn't moving at all. We ran into it. And that's very interesting. And so some people have tried to hypothesize what that could mean. We suspect that this thing was kicked out of a young stellar system when its planets were forming. So a new star that had been

born, say, millions of years ago or something like that. And stars form out of clouds of gas, and clouds of gas typically are kind of stationary in the galaxy. So everything orbits the galaxy, and if you just sort of look at the velocity on average of all this stuff orbiting, that's what I mean by standing still. That's what we call the local standard of rest. And that's the orbit you would just expect stuff to take if it hadn't been pushed around gravitationally by things. So gas tends to be in that kind of an orbit. The stars it forms tend to be in that kind of orbit. And the stuff that gets ejected from those young stars tend to be in that kind of an orbit. The sun is over four billion years. In those four and a half billion years, it's had close encounters with stars, it's gone by

giant molecular clouds, it's gotten perturbed and bumped around. And now its orbit is kind of wonky. It kind of bobs up and down and in and out, and it has this velocity. And it's that velocity that we saw reflected back at us from Omuamua. So the story that makes sense, but again, big error bars, is that a nearby cloud of gas formed a star millions of years ago in this special velocity frame, in this kind of orbit around the galaxy. That star kicked out Omuamua. Omuamua has very low velocity with respect to that star because it just barely escaped. and then whack, the sun came and plowed right into it. So it all kind of hangs together.

And the sort of more sensationalist view is that it's like a buoy. It's some sort of like it's at rest with respect to the galaxy to serve as like a navigational beacon or something. Right. And so Avi sees this special velocity. It says, what are the odds that it would have that velocity? And we're like, well, you know, pretty good if it's a young object because that's the velocity young objects has. It's never mind. Lots of things going different velocities.

Why would it be special? So then he dreams up a reason why aliens might want to put an object in that particular reference frame. And so he suggested it was like a buoy, that it sits there for some purpose at that velocity. And then I guess the sun came along and knocked it out and now it's, you know, headed off in some other direction. I mean, I guess, I don't know why they would do that. It also doesn't seem consistent with it being a light sail. If it's just a discarded light sail, that's not a buoy. That's just a piece of litter.

Or maybe the thing that got launched was a buoy, and it's, I don't really understand. Anyway, you know, you can always dream up some reason aliens might make something have a particular character, but I'm not sure for Omuamua, we have one story that explains all of these characters. So then to wrap up, Omuamu is definitely an interesting object, right? It had a sort of unusual shape, maybe some unusual reflectivity, fascinating acceleration, tells us something maybe about the population of these things in our solar system and in other solar systems, the velocity of stuff. But all in all, what is your best hypothesis? Is it that it's some chunk of nitrogen or hydrogen ice that the sun basically plowed into? Yeah. So with the caveat that I'm not a planetary scientist.

Like I got into this because people were asking me as the director of the Penn State Extrrestrial Intelligence Center what I thought of claims that might be a spacecraft. And so in addressing those claims, you know, I had to learn from the planetary science community what was weird about it, what wasn't weird about it. And so, you know, I worked with two planetary scientists, Sean Raymond and Steve Desh, who taught me a lot about these things and about what we do and don't know about Omuamua, and we thought about all of the different suggestions that have been made. So I basically reflect what they as experts tell me sounds most reasonable, and that is that it's a chunk of ice, that it's a comet that has some weird kind of ice. And that's really interesting. Steve's preferred hypothesis is that it's nitrogen ice, and he's worked really hard to show that that that fits all the data very well and is a plausible substance.

Other people like hydrogen. And, you know, there also might be ideas that just we haven't come up with yet. It could be that when we finally get a close look at one of these things, we're surprised. Oh, of course. That's why Omoa-Mu-Mua looked like that. Tell me what your thoughts are about the sort of role of these crazy hypotheses in science. You know, Avey makes a lot of noise about being like Galileo, you know, that his ideas aren't being taken seriously, et cetera.

Tell me, do you think it's useful for us to entertain these crazy ideas? What do you think about, is the comments he's made in public about this versus the comments he's made in sort of more academic settings? I think it's really important that we constantly challenge conventional wisdom, especially in areas where we have very little data, like small objects around the sun or interstellar comets. And I think it's very easy for us to feel like we've got everything figured out and then be blind when data showing us that we're wrong comes along and rejecting it. And it's like, oh, well, that's an extraordinary hypothesis that we could have been wrong. But for the most part, I think scientists are really eager to be the one that makes that big surprising discovery. We tend to be very open-minded about this stuff. And, you know, when this started coming through, science fiction had already primed us to think it might be an alien spacecraft.

You know, there's this story by Arthur Clark rendezvous with Rama. And on Twitter, as soon as it, you know, was announced, we were joking. Like, oh, we've got to name it Rama. Maybe it's an alien spacecraft. Like, you know, this idea was out there. These kinds of challenges to our conventional thinking are important. And I think in general, they are appreciated by most scientists provided, you know, the level of certainty that's being conveyed here is appropriate.

You know, have we considered this? Have we ruled it out? Could it be? This is kind of weird. Wouldn't that be cool? You know, as long as you're acknowledging the weight of evidence that it's not from prior experience, I think it's fine. where I think Avi Rankles a lot of people is by, you know, claiming that, you know, his ideas

are being shot down, you know, just because they're radical and not because of the certainty he's conveying to the public and how likely it is. I mean, he wrote a whole book that, you know, it hedges a little, it's a little mealy mouth, but it's basically making the argument that it must be an alien spacecraft. And he makes statements in the media that, you know, it really needs to be artificial, when that's not true at all. And that's when people really start getting, you know, upset with a lot of obvious behavior. And then, you know, when he comes back and says we're just being closed-minded and we're just, this is just professional jealousy of all the attention he's getting, you know, that gets old really fast. Right. You wrote in your essay,

quote, Loeb's work is unambiguously counterproductive, alienating the community working on these problems and misinforming the public about the state of. of the field. And as somebody who works both in academia trying to understand sort of the cutting edge knowledge and interfacing with the public, I'm definitely sensitive to this question of like how we present our work to the public with all of its nuances and caveats and how that reflects the work being done sort of at the cutting edge. It's important to get that balance right. I agree with you. Yeah. And you know, to be clear, the problem isn't that he suggested it's an alien spacecraft, right? That's not counterproductive. That's fun. That's interesting.

we should be wondering, just like Shalovsky did, if we might be able to find alien spacecraft in the solar system. That'd be very cool. At least, we can show there aren't any. And, you know, that's something people have studied and talked about and, you know, is very appropriate. It's the, you know, my objection is to the level of certainty that he projects on the fact that this is one to the public, but also the way that he dismisses expertise of people who have studied this stuff their whole careers and gets angry at them for contradicting him. and just tells people that they're wrong and closed-minded and they don't know what they're talking about, even though they, you know, are the ones that have degrees in the field and have studied it for decades,

you know, and he's just coming into it for the first time. Right. And of course, every scientist would love if he was right. If we did discover aliens or a piece of alien junk, we'd all be jumping for joy. Something else you wrote in your essay, quote, there is little joy for debunking claims in science. I think it resonated with me also because, yeah, we would love to make this decision. discovery. But of course, we got to be cautious and we got to be careful, extraordinary claims and extraordinary evidence, as we've always said. Yeah, that's right. And it really is no fun

debunking claim. In the early days of planet discovery, when I was a graduate student, there were lots, you know, every time you found a planet, it was on the front page of the New York Times. And so there was a lot of incentive to fool yourself into thinking that some signal that you detected was a planet around another star. And so there were a lot of claims made that were clearly right, a lot that, you know, a little iffy and some that were just wishful thinking, unfortunately, on the part of the astronomers that made them. And we were always torn. Like, do we stop the work we're doing, finding these new planets to go and debunk this other claim and kind of clean up the mess and say, no, no, that one turned out not to be right. Because, you know,

that's no fun. No one likes being the party pooper. You know, that person isn't going to like you very much after you've done something like that. But also, you've better things to do, right? You have cool new planets to go fine and you only have so much time and so it is frustrating and you know it needs to be done when claims reach a certain level of attention that you know someone needs to come in and sort of spell out actually you know what we really think about it well thank you very much for taking the time to go through all these points and give us an understanding of what sort of the cutting edge science is on these questions and thank you very much for talking to us today very helpful and a lot of fun to learn about this what do you think the future holds for this field do you

think we'll see more of these things coming to our solar system and learn more about the sort of small dark objects in our own solar system and the rest of the galaxy? Yeah, I really do. The Ruben Observatory is coming online in just a few years, and it's going to perform this gigantic survey. It's going to image the entire southern sky every three days, basically. And it will have so much light collecting power, and it will survey so much of the sky at once, that it will probably find things like Omua Amua almost every year and that means we'll have a lot of these to study

and we'll be able to catch some of them on the way into the solar system and see how much mass they lose. We'll be able to see how many of them look like Omuamua, you know, and try and learn about their characteristics more generally. There are even plans which I just find amazing and wonderful

to launch spacecraft to go catch one of them. Now they're moving too fast to actually just straight up catch, but you could launch something that sort of lurks in the solar system. And when an opportune one comes on that it could intercept, could fly in the way and intercept it and get close up pictures and maybe even get a sample. Wow, that would be awesome. And I do still, of course, have some hope that maybe one of them is a piece of alien space junk. And that would be an incredible discovery. That would be pretty cool. I'd be very excited about that. All right. Well, thanks again very much for coming on the program today.

My pleasure. Thanks for having me. All right. That was a great interview. It's kind of interesting that Jason's job is also to look for extraterrestrial life. Yeah, he's definitely interested in this stuff. And like many of us, he wants to discover aliens, right? Nobody is out there debunking obvious claims because we don't want to believe in aliens. We all want to believe it. It would be the discovery of the millennium of history. But we also don't want to mislead the general public about something that was most likely just a chunk of ice.

And so in general, Jason thinks that it could all be explained. All of the weird things about Omuamua have. have a more non-alien explanation. Yeah, Jason thinks that this is actually teaching us something about solar systems. That Omuamua may not be that unusual and that there might be these chunks of ice out there in other solar systems and in ours. One of the big points in the book is that this thing looks different from the things in our solar system. But Jason points out that we're not great at seeing these things even in our solar system.

So it might be that there's a whole hidden ocean of these chunks of ice out there in our own cloud. We just didn't know about them. And so maybe Omuomu is not that unusual. It's just sort of telling us something about the world out there and our own backyard. Have we seen anything like it since? It's been now five years. Well, we have seen another interstellar object. 2i Borisov also came through our solar system a couple of years later. And people have started looking for Omuomua like objects in our solar system. And they've seen a few. They've seen some dark comets, these things that have non-gravitational acceleration without displaying any sort of tail or coma. So I think it really has cracked open the door for us understanding our own solar system a bit better. Or maybe the aliens are just sending us a bunch of messages. Or maybe we're a popular tourist destination. Or maybe we're just a dumping ground for alien junk. No, but the junk left, didn't it? Oh, that's true. Yeah. Maybe we're just a byway for alien junk towards the galactic dump. Well, I guess that would still be a pretty interesting discovery. Alien junk mail. That would be awesome and I look forward to the day. Aliens, please do send us your

junk. All right. Well, we hope you enjoyed that. Thanks for joining us. See you next time. Why are TSA rules so confusing? I'm Manny. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that. Why are you screaming?

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