Planetary Radio: Space Exploration, Astronomy and Science - Is ‘Oumuamua a Piece of a Pluto-Like Planet? And Ingenuity’s First Flight on Mars

Episode Date: April 21, 2021

We begin with a thrilling recap of the successful first flight of NASA’s Ingenuity helicopter on Mars. Then we meet two researchers who have come up with a fascinating explanation for the first interstellar object discovered as it passed through our solar system. Rock out with Planetary Society chief scientist Bruce Betts as we discover the ‘80s band that made a hit out of the first Space Shuttle flight. Discover more at https://www.planetary.org/planetary-radio/steven-desch-alan-jackson-oumuamuaSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Ultimatr data confirms that Ingenuity has performed its first flight, the first flight of a powered aircraft on another planet. Welcome. I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. That was the scene in a room at the Jet Propulsion Lab very, very early on Monday, April 19th, as the Mars Helicopter Ingenuity team learned that its years of work had led to a successful flight on the Red Planet. More Ingenuity coverage is minutes away. We'll also sit down with two researchers who believe they have found a better explanation, a purely natural explanation, for that interstellar visitor called Oumuamua.

for that interstellar visitor called Oumuamua. Later we'll join Bruce Betts for an especially fun What's Up and your chance to win the Mars Pocket Atlas. Another region of Mars tops the April 16 edition of the Downlink. It's a Mars Odyssey orbiter false-color image of the planet's polar cap that reveals ice among dunes that look like loosely woven fabric. You can see it and much more at planetary.org slash downlink, including these stories. The gigantic multi-layered sun shield on the James Webb Space Telescope has been neatly folded away, much like how we packed the thin sail of our tiny light sail spacecraft, though on a far larger scale,

that shield won't unfold again till the JWST is in space. OSIRIS-REx has made its final close pass over Bennu. It will depart the asteroid on May 10th, heading for its climactic sample return to Earth in the fall of 2023. And Blue Origin ran another flawless test of its new Shepard spacecraft. The capsule was boarded by a test crew that exited before launch. It was a run-through of the upcoming mission that may finally take passengers on a suborbital flight. Godspeed, folks. It's Friday, April 9th. NASA and JPL have decided that Ingenuity will attempt the first flight of a heavier-than-air aircraft in two days. Project Manager Mimi Ong, who was my guest back in

2019, is on stage to share her thoughts and hopes. You'll first hear Mimi in this very compressed clip, followed by NASA Associate Administrator for Science, Thomas Zurbuchen. And then a question from a reporter who was caught up in the excitement. Well, the moment that our team has been waiting for is almost here. Each world gets only one first flight. So as Thomas mentioned, the Wright brothers achieved the first flight on Earth. Ingenuity is poised to go for being the first for Mars. It's going to be a flight experiment.

Flight experiments are as old as flying, right? So the Wright brothers' first successful controlled flight, powered controlled flight, was a flight experiment. You know, we have to test to advance. And that is what building first-of-a-kind systems and flight experiments are flight experiment. You know, we have to test to advance. And that is what building first-of-a-kind systems and flight experiments are all about. Design, test, learn from the design, adjust the design, test, repeat until success. Same with ingenuity, Mars helicopter. We started with the fundamental question, really serious question of, is it really possible, whether it's possible to fly a helicopter on Mars? And it's challenging for many different reasons.

Most important of all, the atmosphere at Mars is extremely thin, right? It's 1% compared to the atmosphere we have on Earth. And it is very cold at night. The vehicle we send there has to survive cold nights on its own. It has to charge itself. And the winds are new to us. On top of it all, this flight experiment that we are performing at Mars has to be operated from back here on Earth. We demonstrated first full flight controlled, controlled flight, power flight in our chamber in 2016. We went on to then develop the full up model that is needed for the system to need to fly a test

at Mars and as we call it the engineering development model we demonstrated full success test flight. We flew it successfully in our chamber in 2018 and then we built ingenuity which we flew in our chamber in 2019 so this is the result so this little four pound vehicle the vehicle that you're seeing is four pound has been surviving on its own the cold nights the temperatures there get down to minus 90 degrees centigrade, like minus 130 degrees Fahrenheit. It's been surviving its own. It has been successfully charging, it's recharging its battery during the day. It has been communicating to a space station that resides on the rover, ultimately exchanging information with us, and we have fully confirmed that

it has enough energy and power to perform this flight at Mars. And the flight at Mars is high power. Peak powers exceed 350 watts. And the last time Ingenuity flew was here at JPL in the 25-foot chamber with us, with our team. And at that time we said, you know, next time Ingenuity flies, it will be at Mars. Please join us. Regardless, we will learn whether it's success, failure, interim. But one thing is for sure, we have done

everything we can. And if we don't make that first attempt, for sure, we will not make progress forward. I just want to go back to Sojourner and remind everybody that Zojourner also was a tech demonstration, a tech demonstration by the way without which we could not imagine perseverance, we could not imagine more sample return which was really pioneered with this and for me you know what Zojourner did exactly what Mimi just said which is if you want aggressively punch out the space in which it can operate, taking risks, excessively larger risks, and the month of ingenuity will really be a demonstration of the capability that is there and leading to the very success, I think, in the long run that Sojourner has, a success that at the time of Sojourner, of course, was not imagined that we

could be sitting here with Perseverance there on Mars sample return. Can you only imagine what will happen after this month of ingenuity just two decades from now or one decade from now? Up next on the phone line is Matt Kaplan from Planetary Radio. Hi, everyone. Thank you for this. Really thrilled, looking forward to Sunday. Going back to Thomas' comment about Dragonfly, that maybe Mars and Titan don't have a lot in common, but Mimi, I'm wondering if you are trading information with those folks, and I'm sure they have high hopes

for your success. Oh, yes. In fact, Michael Rikskevich, who leads the space division in APL, where Dragonfly is being developed, Michael Rikskevich was our independent review team chair throughout the lifetime of Ingenuity Mars Helicopter Development over the years. So, yes, and, you, while the dragonfly is flying in the thicker atmosphere, right, so it's a different kind of vehicle, it's heavier. At Mars, it's all about being light and, you know, more autonomous, and it's a different kind of challenge. However,

where we can learn from each other is with being the first rotorcraft in a flying vehicle on another planet or in in the case you know that around a moon with atmosphere but not at Earth it has been a challenge at Amy uh described and I think and describe more how do you test this vehicle right so you have the fundamental models yes you spin you generate lift and control fast enough you can fly easier said than done right how do we go about testing it and we've had incremental uh steps in how do you spin it how do you you know measure the force check the torque cancellation i think that methodology that we've had to invent in parallel to inventing a first aerial vehicle for a planetary exploration that will be very much applicable. And Michael Rikskevich is very familiar and I'm sure will be interacting further as they go into the V&V phase.

We've had initial conversations as well. That first flight was not to happen on Sunday. A software anomaly was soon remedied, though, and the team was ready to try again in the early hours of Monday morning. and the team was ready to try again in the early hours of Monday morning, key members of the team, including Mimi, sat in front of their laptop computers at a ring of tables. It is reporting having performed spin-up, take-off, climb, hover, descent, landing, touchdown, and spin down.

And altimeter data confirms that Ingenuity has performed its first flight, the first flight of a powered aircraft on another planet. So the image we're looking at on the screen is the image from our onboard navigation camera showing us hovering above the surface of Mars. How incredible! And that's its shadow, right, Taryn? Yes, that's its shadow. So the onboard navigation camera points straight down, so we're seeing its shadow right now. I can just hear Mimi in the background, this is real, this is real!

It's so amazing. Yeah, everyone's really feeling it now. So we're gonna wait for the perseverance rover image Well, I got to tear up the contingency speech, which I never practiced, but I was going to read. But I'm lucky for you, I have a much shorter speed for success. We can now say that human beings have flown a rotorcraft on another planet. Later that morning, an exhausted but very happy team heard acting NASA Administrator Steve Jerzyk begin a post-flight briefing. After Steve, we'll let Mimi close our coverage. I make a trip to JPL about once every year, and they'd always take me over to Mimi's

lab, the Mars Helicopter Lab, and Mimi would tell me what they've accomplished and all the challenges they've had and what they've had to overcome. And her just excitement and enthusiasm for making this happen was infectious. I think her leadership, along with the talent of the team, made me believe that they could do it. And they did. So, again, congratulations. Our team has been working over six years, some even longer, towards the dream of experimenting the first ever flight at Mars and this morning our dream came true. If we can play this video, taking off, goosebumps, it looks just the way we had tested in our test chamber, space simulation simulator chamber here, absolutely beautiful flight. I don't think I can ever stop watching it over and over again and lands unforgettable day unforgettable day and you know it's all

about the team to start with really you know our team across JPL Ames Langley with our industrial partners Air Environment Qualcomm Solero Lockheed others we were a team I mean just a strong team and during this morning with our industrial partners, AeroVironment, Qualcomm, Solero, Lockheed, others. We were a team. I mean, just a strong team. And during this morning downlink, I did say that we had many friends who contributed to our success, okay, and including Perseverance rover team and many, many others. And some of them are far away now. And again, as Thomas mentioned Jacob Jacob Benziel I'm sure you were watching our first flight

from the Jacob Overlook so we're thinking about you Jacob so with that this early morning flight what it means for our mission success Mars Helicopter Ingenuity Technology Demonstration Project has three goals in align with NASA's agency level objectives. So the first is to show on Earth that it is possible to fly power control flight at Mars. We did that before we were launched. And then the second goal was to actually fly at Mars. We have done it! This is the first time I've been able to say we've done it. And the third goal is to get data back that will inform engineers that are going to design, that are designing future generations of Mars helicopters. And we have done that too, and we're going to continue.

So beyond this first flight, over the next coming days, we have up to four flights planned and increasingly difficult flights, challenging flights. And we are going to continually push all the way to the limit of this rotorcraft. We really want to push the rotorcraft flights to the limit and really learn and get information back from that. As you may have heard, Ingenuity carried a tiny piece of fabric from the Wright Flyer that crossed the sands of Kitty Hawk in 1903. Congratulations to everyone who contributed to this magnificent achievement of the 21st century. When we return, we'll talk with two researchers who have come up with an entirely natural, yet utterly fascinating explanation for that interstellar interloper called Oumuamua.

See you in a minute. Where did we come from? Are we alone in the cosmos? These are the questions at the core of our existence, and the secrets of the universe are out there, waiting to be discovered. But to find them, we have to go into space. We have to explore. This endeavor unites us. Space exploration truly brings out the best in us. Encouraging people from all walks of life to work together, to achieve a common goal, to know the cosmos and our place within it. This is why the Planetary Society exists.

Our mission is to give you the power to advance space science and exploration. With your support, we sponsor innovative space technologies, inspire curious minds, and advocate for our future in space. We are the Planetary Society. Join us. What was Oumuamua? That was the question I discussed with Harvard professor Avi Loeb not long ago. Avi's hypothesis regarding that very strange object caused a good deal of controversy, but he believed it was the best fit for the

available data. Stephen Desch and Alan Jackson are scientists in the School of Earth and Space Exploration at Arizona State University. They have published a pair of papers that detail a very different explanation, one that doesn't rely on an alien intelligence. When I read about their work, I knew it was a story we should bring to Planetary Radio, so I was delighted to join them in the recent virtual conversation you're about to hear. Guys, congratulations on a publication last month of these two papers in the Journal of Geophysical Research. Alan,

I saw that you were lead author for the first one and Steve, that you took that position for the second. Sounds like you got a good partnership going here. Oh, yeah, we're quite a team. I like working with Steve a lot. It's been great fun. Let me tell you how delighted my colleagues at the Planetary Society were when I told them that I would be talking to you about your recent publications. Because it was only last January that I had Avi Loeb, your colleague at Harvard

University, on the show. And while I enjoyed his book, Extraterrestrial, very much, I had some serious doubts about some of his conclusions. And maybe we'll talk a little bit more about that. Did you guys get to read a little bit about that? And what were your thoughts about his hypothesis regarding Oumuamua? Steve? Well, I have not read the book. I have read some of the papers that have been posted on the archive preprint server and the published paper as well. And so I'm aware that they find natural explanations dissatisfying, at least the ones they were aware of or had thought of at the time that they were publishing these things. And so feeling that they had exhausted all the possible natural explanations, they were ready to move on to some more complicated, less simple, less Occam's razor sort of explanations. Wes Occam's razor sort of explanation. We weren't quite ready to go that far to make that leap yet. And we were convinced that there had to be some sort of natural explanation. And we pursued that.

And you may have found that as we will explore in moments. Alan, did you want to add anything? No, I think Steve covered it quite well. Similarly, I have not had a chance to read Avi Loeb's book. I have read the papers that he's written on the subject. But yes, I think Steve summed up our opinions quite well. So like I said, the hypothesis that you guys have come up with, much more comfortable, much more natural. And you took into account a lot of factors which you seem to have found a quite logical and natural explanation for. Maybe, Steve, if you could start, take us through a little bit of what the true nature, as you guys see it, of Oumuamua seems to be. The true nature, that's a loaded term these days.

I think we have to be very careful about making sure our language is precise and adhering to the scientific method. Certainly, though, yeah, we feel that this is a simple natural model that is consistent with all of the data that we have in hand for this object. And it's a very interesting object because it passed through the solar system in 2017, came by the Earth. We only got observations for a few months, and now we will never see it again, not that particular one. And so there's a well-defined data set. We know

everything we're going to know about it, and can we explain it? And our hypothesis is that it is basically a piece of nitrogen ice, just like the ice that we observe on the surface of Pluto. So just to put it very bluntly, if you were to take a piece of Pluto's surface, that is tens of meters, less than 100 meters in size, and throw it through the solar system in the way that this object came in, it would behave and look and act just exactly like a moon would. So to us, that shows a lot of consistency. Alan can talk about those things. And they were in the first paper that he led. And in the second paper I led, we talked about the likelihood that fragments of a Pluto-like

exoplanet could have encountered our solar system. So, Alan, how do we explain the odd shape? I mean, originally, and in all those very popular, probably too popular artist concepts, we saw Oumuamua as this long cigar-shaped thing. And it turns out that that probably wasn't terribly accurate. But how did it, I mean, it didn't start out looking like an interstellar pancake, right? According to your hypothesis? Yes, no, that's right. The distinction between

the cigar shape and the pancake shape, they're difficult to disentangle just because all we have is just the light curve observations. All we have from the observations of Oumuamua is just how the brightness changed. We don't actually have resolved observations that could directly show us the shape so in terms of how the light curve changes the cigar shape and the pancake shape give you kind of similar things which is why there was that kind of initial which one is it but yeah so in terms of how it got to that kind of extreme shape because whether it's cigar shaped or pancake shaped, that's not something that we see in the solar system. So how it got to that kind of extreme shape is much the same way that if you have a bar of soap, and you've been using it in your shower for quite a long time, you know, it starts off as a fairly chunky object. And in the end,

you're left with this annoying little sliver that you're not quite sure what to do with. And it's exactly the same kind of process that as you're removing material off the surface of it, it gradually becomes a more extremely elongated object. I was hoping you'd use your bar of soap analogy, which I have seen elsewhere. analogy, which I have seen elsewhere. What was it that changed the aspect ratio, if you will, of this object as it, you know, set out from its original solar system somewhere far out there across the Milky Way? And did that process accelerate when it got to our neighborhood? Yeah. So the way that it works is, you know, so if you have an object and you're just kind of eroding it uniformly on the surface so like in interstellar space it would have been being eroded by cosmic rays which would be uniform

on all sides in any case you're just removing kind of thin onion shell layers from the surface of the object you can kind of imagine if you have a layer that's the same thickness all the way around and the object is slightly thinner in one direction than the other if you're taking the same amount off then that's proportionately more of the smaller dimension than it is of the bigger one so the smaller dimension the the aspect ratio between the two increases you know so that would have been happening very slowly and gradually as it passed through its dust base just through this slow erosive action of cosmic rays but yes then when it got to the solar system you started getting the thermal sublimation as a

result of sunlight taking over from that process and that sped up a lot almost all of kind of the change that we see to get it to the extreme aspect ratio that it was when we observed it happened very close to pericenter when it went closest to the sun, because it got closer to the sun than Mercury. One of the surprising things is how much mass has to be lost. 95% of the mass has to be lost in order to get it to that very, very flat pancake shape that it's referred to be. And that is a surprising amount of mass loss, but not when you consider that it's made out of nitrogen ice, which is stable on the surface of Pluto, but not closer to the sun. It tends to sublimate at temperatures 25 to 50 Kelvin, depending. And yet it was closer to the sun than Mercury. So once you see it in that light, that you have a chunk of Pluto that is inside the hottest

or at least the closest planet to the sun, then it's going to lose mass like crazy. What a shame that we couldn't point the radar at Goldstone or the late lamented Arecibo dish at this object and get more back from it than just that light curve that you talked about, Alan. And I wonder if one or both of you could say something about why Oumuamua's albedo or its reflectivity is one of the most important pieces of this puzzle. Because we don't have the kind of absolute shape, again, we don't have the absolute size. And so the way you convert kind of brightness into a size is by knowing how reflective the object is. If you don't have any kind of intrinsic expectation for what that albedo, what that reflectivity is going to be,

then you have to either make an assumption, which the previous assumption was that the albedo was similar to solar system asteroids, which when people thought, well, it looked like an asteroid, then that was a logical assumption to make. But then, so when we were thinking, well, okay, maybe it's some kind of slightly more unusual thing, like a piece of nitrogen ice, then, well, what albedo should we expect that to be? We're not sure. So what we did was we let that just be a free parameter. And once we'd gone through the calculations, we saw what albedo fit with the rest of the observations. And it turned out rather neatly that the albedo that worked was the same albedo that you observe for the surface of Pluto. Steve, it strikes me that this was one same albedo that you observe for the surface of Pluto.

Steve, it strikes me that this was one of those great aha moments in science. It was. I remember when we had this conversation online because, of course, pandemic. So we were in different cities, even though we usually would be down the hall from each other. But we were having one of these late night chats back and forth about what the albedo should be. And we realized that there were actually two solutions. And one of them was a high albedo solution that just exactly fit an albedo of 63% or something, an albedo that just exactly matched with the nitrogen ison Pluto is. And we realized everything fit together. It was a great moment. Alan Stern of the New Horizons Mission, frequent guest on this show, and it only now occurs to me how useful it was to have that close flyby of that planet or dwarf planet, take your pick,

so that you could realize you had a very close analogy in terms of this structure or this material. Absolutely. I think that the exploration of our own solar system and the understanding of what happened to our solar system is absolutely critical for all of this. It's certainly true that we have had ground-based observations of Pluto and had inferred already that it was mostly nitrogen ice. But the remote sensing and the flyby photos all paint this really vivid picture of how nitrogen glaciers are actually flowing across the surface. They give us an idea of how the nitrogen came out from inside the planet onto the surface

and how much nitrogen ice there probably was in the past. All of that was super critical to shaping our thinking. Do we have an idea of the mechanism that might have launched Oumuamua on its journey across this corner of the galaxy? Yeah, it's two steps. There's the ejection from the planet and then there's the ejection from the solar system. I think that a lot of people misinterpret our work to think we're doing it all in one step. But that's not how it would work in our own solar system. Did you want to cover those, Alan? history of our solar system, we believe Neptune and Uranus were originally quite a lot closer to the sun. So the giant planets were in a more kind of compact configuration. And then at some point in the history of the solar system that changed, there was some kind of instability that stirred them up and Neptune migrated outwards. In that process, it migrated outwards into the primordial Kuiper Belt and swept

away most of what was originally there. The Kuiper Belt that we see today is only something like one thousandth of what was originally there. At some point in the early history of the solar system, there were probably a few thousand objects like Pluto, whereas now there's only a couple. As you can kind of imagine, if you're throwing thousands of Pluto-sized objects around, some of them are going to crash into one another. In spectacular fashion, no doubt. Indeed, yes. Yeah. So we calculated all of the impacts that would have happened onto the surfaces of these actually thousands of Pluto-sized objects and determined the total amount of mass that would have been ejected as collisional fragments. It adds up to something

close to a tenth of an Earth mass, which is quite a lot of mass. I mean, it's like a Mars mass of fragments, but it's actually a very small fraction of the total mass that was in the primordial Kuiper Belt. So these fragments were flying all over the place. It was a very messy environment. Like the comets that were ejected by Jupiter, mostly, some of them being placed in the Oort cloud, and a larger fraction being ejected from the solar system altogether. These collisional fragments also would have been ejected from our solar system. And if other solar systems were doing

the same thing, then they also would have ejected collisional fragments of ice from the surfaces of these Pluto's, which would have been largely N2 ice. What can we infer, if anything, from the speed at which Oumuamua passed through our solar system and possibly also the vector it was on, the direction it was coming from? Do we know how long it may have taken to travel here and where it may have come from, Alan? Yes. So we have some kind of rough estimates on the basis of what speed it approached the solar system at. The stars and the sun are all orbiting the center of the galaxy, but on top of that, there's kind of these random motions. So if you average out all of those random motions to

just kind of get the orbital motion, you get what's called the local standard of rest. Relative to that, the sun is moving at about 20 to 30 kilometers per second. Oumuamua, when it approached the solar system, approached the solar system at about, I think it was 28 kilometers per second, but most of that was because of the motion of the sun. In some sense, the solar system crashed into it rather than it coming into us. It was almost standing still. Yes.

So relative to that local standard of rest, Oumuamua was only moving at about nine kilometers per second. So quite a bit slower than the sun. If you kind of look at stars, that random motion relative to the local standard of rest isn't constant over time. It slowly increases as stars get older and they have more encounters with other stars that kind of gradually puffs them up a bit in terms of their velocities.

On the basis of the fact that it had a relatively low speed, you can say it was no more than about 2 billion years old. So no more than about half the age of the solar system. In terms of direction, I think it was coming from roughly the direction of Vega, but that's because that's the direction the sun is moving in. Because it's relatively young, then this was a more speculative thing we suggested that perhaps it originated in the perseus arm because there are lots of young stars there and like we said young stars would be moving slower relative to the this random motion and that would have meant that it was traveling for about half a billion years which kind of made sense right yeah it was coming from the direction of Vega, but coming from much further away than Vega, presumably. And it has been traveling for an

unknown amount of time. How long it's been traveling depends on how much you think we understand the erosion by cosmic rays while it's in the interstellar medium. Also, what we think its original shape must have been as it left its solar system. And because those things are not well known, I think we have to call this part speculative. But it would be a typical age, we think, to be traveling through the galaxy for about a half a billion years. And given the speed it was coming at the solar system with,

with respect to local standard of rest, this would mean it would have come from the next spiral arm over, which is the Perseus spiral arm. And that definitely makes sense because it has to come from the young solar system based on the fact that it has a low velocity with respect to this local standard of rest, but also the instabilities that are required to eject these objects probably only happen very early on in solar systems history,

if ours is any kind. I'm blown away. In spite of how immature our understanding of these objects and the mechanics behind them are, at how much we are still able to infer in the way that you guys have. Regarding that speed of Oumuamua, one of the questions that I asked Avi Loeb in January, you know, of course, his hypothesis was that it's a light sail, that it was probably propelled

by giant lasers or something else that would have moved it up to a substantial portion of the speed of light, one would think. My question for Avi was, well, then why is it going so slowly? And frankly, he didn't have a great answer for that. And your hypothesis, your theory seems to coincide much better with what we've observed. Thank you. Yes, I mean, that is something that that issue with the point of light cells is you want to accelerate it to a significant fraction of the speed of light. Yeah, that is an issue that I have thought about with Avi's idea myself. It gets into these questions about the scientific method and Occam's razor. And of course, it could be a light sail in principle. We should probably look at some of the

implications of that. For example, was it directed towards us and functioning and keeping the same face towards the sun? No, apparently not if it was tumbling. So if it was not functioning, how many of these objects are just randomly flying through space? Either way, you either have to explain the tumbling or by invoking an incredibly large number of such objects. And these are testable, I suppose. I'm not sure exactly how, but you quickly get into these questions of what are the motives of aliens? Can we get into their heads? And there was an amusing article in Zuckerman, I believe, UCLA, arguing that it couldn't be artificial because no self-respecting alien would build such a thing.

Which is also, I guess, a defensible position. But you can see we quickly get into territory where you can't test things because we simply can't get into the psychology of aliens. So let's try to exhaust all the natural explanations and see if we can find one that makes sense. And it doesn't mean that there are no alien artifacts. It certainly means we should probably try to imagine the simpler explanation first. Extraordinary claims, extraordinary evidence, right? I just think it's freaking cool. There's like a piece of an exoplanet that has passed through our solar system.

And it's, to me, a little bit of a shame that that's overshadowed by, oh, it's not aliens. What a shame that that's overshadowed by, oh, it's not aliens. I think it's a pretty profound discovery and a really cool object. Getting into the aliens' heads, that's assuming they have heads. Do you expect, now that we know that they're out there, that we will find more interstellar visitors like Oumuamua, and should we make a point of watching for them? Alan? Yes. I mean, I think it's always the kind of the case that once you found the first one,

then you look for them more and then you find them more frequently. And I mean, from that perspective, we are kind of well-placed to do that. So the Vera Rubin Observatory in Chile, it was originally supposed to be coming online later this year i imagine they've been slightly delayed because of pandemic but you know so sometime in the next year or so the virarubin observatory should be coming online and what the purpose of the virarubin observatory is is to to find astronomical transients so objects that change on short timecales, things like stellar objects passing through the solar system. You can kind of think of it as being like a super version of the Pan-STARRS observatory that discovered Oumuamua in the first place. So we expect that Vera Rubin

should find a lot more of these kinds of objects, which will then let us kind of look at them in a more statistical way and test the ideas that we and others have had for it. And it should be noted, of course, there was a second interstellar object, the comet Borisov, that was discovered the following year. To my knowledge, those are the only two, but it does suggest that maybe not every year, but with current technology at least, but every 10 years or something

in that window, we should expect another visitor. We're very keen to get at the statistics of this. One of the things that our papers tend to predict is that these collisional fragments like the muamua are probably not the many a year sort of number. It's probably going to be a somewhat rare event. It maybe depends on the survey capabilities, but I wouldn't be too upset if we found one every 10 years. I think that would be a sort of expected outcome.

But we should definitely look for them because these are samples of exoplanets that are brought to our doorstep and made available for close study if we can just get a little closer to them. And in this regard, the comet intercept mission concept from ESA and the other mission concepts we developed in the U.S. to actually be on the ready. And when you see an interstellar object do a high velocity trajectory to intercept it

and take close-up pictures and spectra and all this, that would be just an invaluable data set. So I'm looking forward to this eventuality. Very, very exciting option for the future. Something to look forward to. And sure, yeah, Borisov and Oumuamua, two data points, not a whole lot to base things on. Do you think that you're going to continue to follow these objects as we hopefully discover more of them?

Yes, I certainly hope so. As and when we find the next one, obviously one of the things we would like to do, if it looks similar to Oumuamua, is to try and detect the nitrogen gas that it must have been producing you know so if a muamua is indeed a piece of nitrogen ice then it should have been releasing nitrogen gas it's just that we weren't expecting to look for that so we didn't see it but if you're expecting to look for it then you can go and look for it. Yeah, to be specific, you need to observe in a very specific wavelength band that is not typical. Very blue up into the ultraviolet and only in that way is it possible to find it.

Otherwise, it's an invisible gas. As you know from Earth. I'm looking through some right now. As we get close to wrapping up, I don't want to ignore the other portions of your careers, the work that you guys are doing. Steve, I'll start with you. I read that you are also working on ways,

like a lot of people, to find signs of life across the galaxy or at least our corner of it. Can you say something about this NASA study that you lead? Yeah, and I've been leading this project at ASU for six years. It's wrapping up now, unfortunately, but it's funded by the Nexus for Exoplanetary System Science by NASA. And this institution funds various universities and institutions to devise strategies for looking for life in the universe. Astrobiology is a major focus of NASA. And it's insulting to hear somebody claim that scientists aren't open-minded to

the possibility of life in the universe, or aren't trying very hard. We are trying very hard to figure this out. One of the main problems is that we will probably find signs of life around another planet by atmospheric transmission spectroscopy by seeing what light is absorbed by a terrestrial planet's atmosphere as it passes in front of its star. And this will tell us the composition of the atmosphere. But that alone is not sufficient information. We think it is because we see on Earth, we have oxygen in the atmosphere. And oxygen is made by photosynthesis. So if we see oxygen, that should mean life. But it's really not that simple. There are a lot of false positives. And that's a lesson that a lot of people working in the field of astrobiology have taken to heart

that it's not enough to come up with an idea that if we look for this, maybe we'll find it. And maybe that would mean life the same as it does here. You have to imagine all of the other alternative possibilities. And in our case, we were funded to study the geochemical cycles on terrestrial planets with very different chemical compositions and imagine what are sort of the false positives that could give you oxygen or methane in its atmosphere without life. And that's a lesson we take forward. And I think other scientists should too, that, you know, it's not just enough to imagine the

one plausible thing. You have to also eliminate all the other things. You remind me of the ongoing discussions regarding the presence or non-presence of phosphine in the atmosphere of Venus. And we go back to Occam's razor again, don't we? It's a lesson we must learn repeatedly. I know from having spoken to Steve and the other people involved with the project at ASU a lot over the last few years, one of the really difficult things

that kind of perhaps you don't think about initially is that finding something on Earth that hasn't been affected by life is really difficult. And so it's kind of difficult to find something that doesn't have life to compare with. Life finds a way. Steve, I also read that much closer to home, you are doing some thinking and perhaps some work related to climate change. Can you say something about that?

Right. And this is one of those unfortunate situations where I'm not funded to do it. So it's a hobby in a sense, but there isn't really a funding mechanism for geoengineering. And I'm not advocating geoengineering per se, but I am advocating that we need to think about ways

that we can actually intervene in the climate because we are anyway, and we're not going to stop. And so we need to have a plan for the case that's coming very soon where climate change will spiral out of control too quickly and there'll be a clamor to do something about it. And so in a paper in 2016, we demonstrated through a sort of thought experiment that it would be feasible to help reconstitute the sea ice in the Arctic by pumping water, basically, and helping it freeze. Just a thought experiment showing that the numbers are big, you know, dollar amounts are in the hundreds of billions of dollars, but it is a feasible thing. And so why don't we study this and think about it more? Because this is a place where climate change is happening more quickly than anywhere else and where these sort of mitigation efforts might have the biggest lever on.

What you've just described, Steve, this approach, I know that you're familiar with the author Kim Stanley Robinson. And in his most recent novel, Ministry for the Future, where he addresses climate change and how we're going to deal with it, I think what you are describing regarding generating more Arctic ice is something that he includes in the book. I wasn't aware of that book, and I'm really pleased to hear you tell me about it. I've read his other books, including the Climate Change Trilogy, and I respect his opinion a lot. I'm keen to see what he says about it.

I recommend the book very highly. Alan, I think up front I described this as the golden age or the beginning of a golden age of exoplanet research. And that seems to be where your focus is. Would you agree? Yes, I think that's a reasonable description. Yes. And I kind of started off more in exoplanets and have shifted a little bit more into the solar system since then. But yes, I still think about both of them a lot. So what else are you up to in your research when you're not coming up with explanations for interstellar visitors? One of the other things that I work on quite a lot is debris disks.

Obviously, we can see planets around other stars, but we can also see analogs to our asteroid belt and Kuiper belt. And this is kind of one of the reasons why Oumuamua was kind of exciting to me, because we see things that look like our Kuiper belt around other stars quite a lot. They're actually a lot easier to see than planets, because you can kind of imagine if you take a small amount of flour and throw it into the air, you can see it very easily, even though there's a tiny amount of mass there. And it works the same thing with a disk of debris. It's a lot less mass than a planet, but it's in much finer pieces. So you can see it a lot easier.

But when we are looking at one of these Kuiper belt analogs, all we're seeing is kind of the very small dust particles, you know, like 100 micron kind of size. And all we can do in terms of thinking about what larger things like Pluto kind of size things that might be there is to make inferences, sometimes based on the structure of the disk. But then with Oumuamua, we can actually kind of directly say, yeah, okay, this came from one of them. So that was kind of really exciting for me and that connected those two pieces of work. It's kind of connected to what, you know, Steve, you were saying about the comet interceptor kind of mission, if, you know, as and when we have another one say okay

we found all of these extrasolar planets most of them are very long way away i mean you know even alpha centauri it's 4.2 light years away we're not going to get there for thousands of years if we wanted to send something there so you know observing an exoplanet up close is not going to happen in the lifetime of western civilization never mind our lifetimes. But when we have a piece of an extrasolar planet come through the solar system, then we actually can do close-up observations of a piece of an extrasolar planet in our own lifetimes. And that's kind of amazing. Steve, I think, again, I'm getting evidence of why you guys have forged such a great partnership.

It's really great. Yeah. Having exoplanets and planetary science all in the same package and we each bring something to the table. for joining me on Planetary Radio, but also for this work, which has given us, as you pointed out, a much more natural explanation for Oumuamua, that first ever discovered interstellar visitor to our solar neighborhood. Good hunting. And I wish you the greatest of success in all this other work that you have underway as we keep working to understand our universe better and better.

Thank you. It's a real pleasure to be here. Astrophysicist Stephen Desch and astronomer planetary scientist Alan Jackson of Arizona State University. We've got links to their work and much more on this week's episode page at planetary.org slash radio. I'll be right back for a good time with Bruce Betts. Time for What's Up on Planetary Radio. Here is the chief scientist of the Planetary Society, Dr. Bruce Betts. Welcome back. Thank you, Matt. Good to be back. How are you doing? I'm doing great. I had so many wonderful birthday wishes that came in from listeners. Thank you, everybody. It was a great birthday. That's amazing. How'd they know it was your birthday? I told them. Good call. I embarrassed you, if it's possible for you to be

embarrassed. It's true. I didn't. You told them about my birthday. Indeed. I was just joshing. Night sky. Let's talk about it. In the evening, Mars hanging out, hanging in there in the southwest in the early evening, looking like a kind of fairly sort of bright red star, still hanging out in a triangle with Aldebaran and Betelgeuse, the brighter red stars right now. In the pre-dawn, we've got Jupiter looking really bright, and Jupiter and Saturn are now pretty darn easy to see. They're up high enough in the east in the pre-dawn, and they will be

hanging out with the moon on May 4th. We move on to this week in space history. It was 1990. 1990 the Hubble Space Telescope was deployed. They just put out a release like a day or two ago with new data. It's just amazing. It's an antique. You know, I think I saw one of them on Antiques

Roadshow. Somebody just had one in their garage. They didn't have room. They had room just had one in their garage. They didn't have room. They had room for nothing else in their garage. Finally got it out, got it to the... Oh, this looks like an antique Hubble Space Telescope. It was originally built...

Oh, okay. Let's move on. On to... Well, that was lovely, on. On to Space Fact! Space Fact! Well, that was lovely, but I just can't resist listening one more time to that great barbershop quartet. Oh yeah, that's better. Space Fact!

Random Space Fact! So Const constellations, the official IAU ADA-approved constellations, a lot of them, particularly for us in the Northern Hemisphere, we get used to ones that are mythologically named, typically Greek mythology. You go to the Southern Hemisphere, you find some that interestingly, thanks to

Nicolas Louis de Lecal, which I butchered because I don't know how to speak French, he named a number of constellations from his observing time in South Africa and he named them primarily after tools.

So we got the air pump, the chisel, the furnace. Of course, we've got them with fancy names, Antlia, Calum, Fornax, pendulum clock, microscope, compass, telescope. So it's really a different feel in that neck of the woods. That's a lot less romantic, if you ask me. Look, the air pump is just looking beautiful tonight.

Not as nice as Pixis, the compass. Yeah. I like that better actually. Yes. Okay. That wasn't very good. There you have it. We'll come back for a little fun and constellations in the trivia contest.

But first we have big fun in the trivia contest. I asked you what famous band was so moved by viewing the launch of STS-1, the first space shuttle launch, that they wrote a song about it. How'd we do, Matt? You're a big fan of this band, aren't you? I am a fan. I am definitely a fan. You're going to recognize these lyrics quoted for us by Michael Kessball in Germany.

Not our winner, but still, excitement so thick you could cut it with a knife. Technology high on the leading edge of life. You want to identify that song? That is Countdown by the band Rush. The Canadian band Rush. That is going to become more significant as we continue to talk about this. A couple of people mentioned the great Kate Bush, whose song Hello Earth also uses some of the STS-1 comms link audio, which was interesting. I did not know that, even though I'm a fan of Kate Bush. Here's our winner, Kathy Koons in Florida. She said, yep, yeah, it was Rush.

She says, sorry, I don't have a poem to talk about Rush and their song Countdown. That's okay, Kathy, we don't mind. She says that we enjoy listening to your show each week on WMFE in Orlando. And yes, I am a member of the Planetary Society. Kathy, we thank you for that. And we also will be happy to send you a copy of Mars and the Movies, a history by Thomas Kent Miller, that very authoritative, very comprehensive book, which has every movie ever set on the red planet. And a few that weren't necessarily set on the red planet, but still involve Martians of one kind or another.

Anyway, that's going to come your way, Kathy. Congratulations. I got a bunch of other stuff. Nick Bell in Indiana had to go find my old tape of it, I guess a cassette, and then realized he had nothing to play it on. Yeah, it's a bummer. Charlie Killam in New Hampshire. I apologize for not responding as a poet. You know, that was the week that we had our little poetry festival, I believe, from listeners. It's really not required, just for future reference. He says he's not a poet. He's an engineer. Oh, like those are

mutually exclusive, Charlie? Yeah, actually. Yeah, they actually are. They are. By the way, I love this album. He says, I've always been a space geek in the fact that all the members of the band hold PhDs. It's true. They're honorary PhDs. They were awarded by a university in Ontario, Canada. They're a great band. They're very talented in ways far beyond my ability to comprehend, but meh. Robert Cohane, Massachusetts.

I guess we could say the first major Canadian contribution to the space shuttle, since the Canadarm didn't fly until STS-2. Ooh, nice trivia. Nice random space fact. Robert Klain in Arizona. If you play Mars Party by the Amoeba People backwards, he swears he hears them say, turn me on, Mars helicopter. I'm not sure what that has to do with STS-1 or Rush, but I thought I was entertained by it. And of course, the Amoeba People,

that's the house band of Planetary Radio. He goes on to ask, weren't you and Bruce in a rock band in the old days? He said, I thought for sure I saw you guys at Woodstock. That would have been so wrong for me to be at Woodstock at so many levels. Even I was not old enough to be in a band at Woodstock. I was, though, a roadie for Country Joe and the Fish. You are just an enigma wrapped in a conundrum, wrapped in a joke.

Wrapped in a fish. Jenny Marie King in Colorado. She got it right, of course, Countdown by Rush, proving that my claim that nerds and rock and roll go together like Bruce Betts and weird noises met with the highest respect. Really? Like Bruce Betts and weird noises. The song contains samples of Bob Crippen and John Young speaking to Mission Control. She says that during Ingenuity's pre-flight briefing at JPL, she was surprised and pleased to hear Mr. Matt Kaplan call in to ask a question as if he's a normal human rather than the king of planetary radio. I like to, you know, put on commoner clothes and mix with the peasants now

and then, Jenny. Yeah. You should see his usual clothes. This goes on and on. There were so many good ones. Martin Hajoski in Texas says it's also possible the three other songs in that same Rush album could have planetary radio associations. Matt Kaplan as the analog kid, Bruce Betts as the digital man, and Casey Dreyer as New World man. New World Man. I got a poem for you from Dave Fairchild, our poet laureate. The band was there the day the shuttle was supposed to fly, the countdown scrub. They had to rush to make their airport time. They played in San Antonio,

then flew back full of life where rush felt the excitement. You could cut it with a knife. Nice. And there's one more. You got that one? I do. I'll first I'll comment that indeed, apparently because the launch delay, they had to go play a concert and and then fly back in time for the launch, which they did because they're into it. Here is a poem from Gene Lewin in Washington. Inspiration comes in many forms

and moves a mortal's soul. Sometimes it's captured in a song. This time, it was rock and roll. Lifeson, Pert, and Geddy Lee used rhythm to convey the launch of the first STS they witnessed on that day. Audio from the crew is heard.

Countdown to the dragon's flames brings to life this awesome force, and Rush is the crew is heard. Countdown to the Dragon's Flames brings to life this awesome force, and Rush is the band's name. Nicely done. You and Gene, you're a good team. We go way back. Let's go way forward. What do you got for next time?

Way forward back to constellations. What is the only IAU constellation, so one of the 88 official constellations. What is the only IAU constellation, one of the 88 official constellations, whose name is derived from a geographical feature on Earth? A feature, a place on Earth, the only one derived from it. Go to planetary.org slash radio contest. It's a little tricky, but I have faith. I do too. And if you want to satisfy our faith in you, you need to get us that response by Wednesday, April 28th at 8 a.m. Pacific time to enter in this round of the Space Trivia Quiz. And we will once again give away this gorgeous Mars Pocket Atlas assembled, edited by Henrik Hargitay, also from Europlanet, the Central European hub. It is gorgeous.

It is just the most amazing little publication. I believe that Henrik will include a little overlay with the nation or state or whatever that you're from that is to scale. And you can lay it over the maps of Mars in the beautiful Mars pocket Atlas. We're done. All right, everybody go out there, look up in the night sky and think about what tool you would name a constellation after.

Actually, how about household appliance? Thank you. And good night. I would choose a microwave oven because it could actually be detected by a radio telescope. The microwave oven constellation. could actually be detected by a radio telescope. The microwave oven constellation. There you go.

It has a modern feel to it. I was thinking more of something that slices, dices, chops, and smashes. But a microwave oven is a very nerdly, wonderful answer. Thank you. Thank you. Did Popeil make microwave ovens? I don't think so. That you. Thank you. Did Popeil make microwave ovens? I don't think so. That's Bruce Betts.

He's the chief scientist of the Planetary Society. He joins us every week here for What's Up? I couldn't think of a funny, what's a funny kitchen appliance? Blender. Blender was the first thing that came to mind. Blender was, that was the first thing that came to my mind. But I was thinking something, wow, all three of us thought blender first. But I was thinking something that Ron Papil would sell.

Oh, the George Foreman Grill. That great barbershop quartet, they call themselves Soundwave. Planetary Radio is produced by the Planetary Society in Pasadena, California, and it's made possible by its members. Naturally, you can begin to understand their nature at planetary.org slash join. Mark Hilverdes, our associate producer, Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser at Astro.