Planetary Radio: Space Exploration, Astronomy and Science - Giving Mysterious Venus the Love (and Science) She Deserves

Episode Date: August 15, 2018

We have so much to learn about Venus, says JPL scientist Sue Smrekar.  What we learn will help us understand our own world and Mars.  Sue joins us this week to make a great case for a new Venus orbiter. The Parker Solar Probe has begun its exciting journey to “touch the Sun.” Our MaryLiz Bender talks with mission leaders before and after the launch. Bruce Betts and Mat Kaplan have two great space trivia contests to wrap up right after they take us on another What’s Up tour of the solar system and back through the history of space exploration.  Learn more at:   http://www.planetary.org/multimedia/planetary-radio/show/2018/0815-2018-sue-smrekar-venus-parker-solar-probe-launch.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Hey Venus, we haven't forgotten you little sister, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. It is our sister planet, after all. Or is it? That's one of the questions we'll ask Sue Schmecker of JPL. Or is it? That's one of the questions we'll ask Sue Schmecker of JPL. Sue has been lobbying for a new mission to Second Rock for years, and she makes a good case. We've got two space trivia contests to wrap up with Bruce Betts, along with lots of other good stuff about our universe, in this week's What's Up installment. We start with something new and different.

The Parker Solar Probe was successfully launched in the very early hours of Sunday, August 12th. Our Mary Luz Bender was there, but she began her coverage of the mission a few days before. The Parker Solar Probe is on a daring mission to touch the sun. Passing as close as 6 million kilometers, it will pass through our star's corona, which extends to about 8 million kilometers. That's far closer than any previous spacecraft and means it will pass through our star's corona, which extends to about 8 million kilometers. That's far closer than any previous spacecraft, and means it will have to withstand intense radiation and temperatures reaching over 1,300 degrees Celsius. That's 2,500 degrees Fahrenheit. With Parker Solar Probe, it's a voyage of discovery.

We're going to go into the last major region of the solar system to ever be explored by a spacecraft. That's the Parker Solar Probe project scientist Nikki Fox. She's been working on the mission for eight years and is anxious to start getting data back once we reach the sun in just a few short months. And we are going to go and better understand the workings of a star. Our star, it's the one in our backyard. It's really the only one we can go and study right now. But the applications are huge. Everything is driven by the sun in our solar system. Betsy Congdon led the team that developed the spacecraft's heat shield.

It will have to protect the spacecraft and its instruments from that horribly harsh environment near the sun. One of the amazing things about being a part of this mission is the textbooks will look differently in 10 years. We will have an understanding of a sun we don't have now, and that's incredible to be a part of such an important feat. The Parker Solar Probe is the first spacecraft to be named after a living human being. Eugene Parker is now 91 years old. In 1958, he wrote an extraordinary paper that was widely shunned by the scientific community,

but later made him the father of heliophysics. It talked about how the atmosphere of our star was continually accelerating and moving out, bathing all of the planets, and in fact, actually shaping our solar system. It was met with a lot of controversy, but it turned out that he was right. A few years later, a spacecraft in the solar wind actually saw what he was predicting. Nikki Fox has spent some time with Dr. Parker. I actually did have the honor of introducing him to the spacecraft. You know, I said, Parker, meet Parker. And he was very touched for him to be here with us at the launch site and seeing his legacy going off to really prove his theories or maybe

to find out that it's something completely different. But it's really important for us that he's with us to enjoy this journey. Launching big scientific missions like this is nerve wracking. After three launch slips, I wondered how they were feeling about this launch day. You know, I got a message on Sunday saying, oh, you know, she's ready. She's in flight configuration. She's buttoned up. The doors are closed. And I, you know, I was I was I'm getting emotional now. I was very emotional there. The excitement is incredible. The excitement mounts every day. We were out on the pad this morning with the sunrise to see the rocket and have a team picture. And I think several of us were wiping away a few tears. On the other hand, Betsy seemed surprisingly relaxed.

I was at the pad when we closed the doors and said goodbye. It's kind of like, wow, we're never going to see her again. She's off. A lot of people kind of talk about it like it's an end, but it's in a beginning. And that's what's exciting. It's like this momentum building towards the real event, which is actually taking the science. That's why we did everything that we did to get to this moment. Nikki had a final message for her team and all other teams involved in building momentum for this mission. I would actually just like to take a moment to thank the entire team. There are thousands and thousands and thousands of people who have poured their heart and soul into this mission really over the last six decades. For this particular incarnation, it's certainly a decade, but there have been many other

studies and many other attempts to fly this mission. For all of the engineers, the scientists, the managers, the city blocks that it takes to be able to put this mission, you know, we're flying it for everybody. It carries the name of Gene Parker, who inspired us to do this amazing mission. But there's a little piece of every single one of those people launching with the spacecraft. Five, four, three, two, one, zero. Liftoff of the mighty Delta IV heavy rocket with NASA's Parker Solar Probe, a daring mission to shed light on the mysteries of our closest star, the sun. It was just a few days later and moments after the successful launch of the Parker Solar Probe that I found a thrilled and glowing Nikki Fox. Congratulations on a successful launch. How do you feel?

I am over the moon, over the sun. It was an incredible launch. It was so beautiful. The weather was perfect. We could see stars. We could see Venus. Up she went, and it was just spectacular. I was standing right behind Gene Parker the whole time and able to watch his look of just pure joy on his face.

It was incredible. Here's to the beginning of a new era in heliophysics and a better understanding of our entire universe. For Planetary Radio, I'm Mary Liz Bender, Ad Astra. Sue Schmrickar is a principal scientist at the Jet Propulsion Lab. It's not that she's exclusively devoted to that cloud-enshrouded world. She is deputy principal investigator for Mars InSight, the geophysics lander that will touch down on the Red Planet in November,

and she has been part of many other missions around our solar neighborhood. But Venus is never far from her thoughts or her research. She co-chaired the Venus Exploration Analysis Group for a couple of years, and as you'll hear, she has proposed exciting Venus orbiters that would have revealed the planet's mysteries as never before. Sue joined me a few days ago at Planetary Society headquarters. Sue, welcome to the Planetary Society, first of all.

Now, I'll throw this at you because on your tour, I encouraged you to sign Bill Nye's Wall of Space Celebrities, which you certainly qualify for. And what did you put on that wall? I drew a picture of the symbols for Earth and Venus holding hands. And that we need to go back. Yes, absolutely. All right. We're going to talk a lot about that. I'm old enough that when I was a kid, there were still coming out with books about the solar system that had artist concepts of Venus as this lush tropical jungle. And if anybody wants to see this on screen, the film that was made of Ray Bradbury's

Illustrated Man, one of the sequences is supposed to be on Venus. Then, of course, people like you and Carl Sagan had to come along and ruin all that and tell us that it's hotter than an oven. Even with that, do you think it's still fair to call Venus the sister of Earth? You think it's still fair to call Venus the sister of Earth? Absolutely. You know, we don't know when Venus lost oceans. We know it had oceans once upon a time. It could have been as recently as a billion years ago. So Venus was likely the first habitable planet.

Beating Mars. Yes, absolutely. Wow. And then on a very different path, but ending up in the same place as Mars, right? Where, well, who knows? The jury's still out. We may talk about that discovery of that lake that we have talked about just a week or two ago on this show. But as a place where life could certainly have existed, but not very likely anymore on Venus, right? Well, certainly the surface is 460 Celsius, 860 Fahrenheit.

Yeah, not too much life on the surface. There are those out there that talk about the possibility of life in the clouds where it's pretty temperate. No evidence of that, but theory says it's possible. And it's above the sulfuric acid rain too, right? Right, right. I guess I wasn't going to bring it up until later, but what do you think of these plans to do more to explore the atmosphere above what you normally look at on Venus or would like to, these proposals to send a balloon? Balloons would be super interesting. I mean, there have been so many exciting mission concepts developed to study different aspects of Venus.

I mean, Venus is one of the few planets in our solar system that has this enormous dynamic atmosphere. You know, the super rotation at the top of the atmosphere, this unknown UV absorber. It has so many mysteries about the atmosphere. And balloons are one of the ways we could address dynamics of the atmosphere. Venus Express has discovered these huge so-called gravity waves. They're really buoyancy waves in the atmosphere that are like 10,000 kilometers. So there are so many things about the dynamics of the atmosphere that we still don't know, and balloons would be ideal for that.

Not to be confused with the LIGO gravity waves. Absolutely. Yeah. Okay. So much more that we should be learning there. And yet, proposals for Venus missions, a couple of which you've made, and I think you've been part of more, haven't gotten a whole lot of love from NASA for a long, long time. I mean, I think Magellan, right, the last U.S. mission, that terrific radar orbiter. But it went out of business 24 years ago. Venus Express finished up four years ago. We've only had a couple of

sort of short flyby visits since then, right? I mean, why? Why doesn't Venus get a little bit more love? Well, you know, there's a Sky and Telescope article coming out in September, and people talk a little bit about this. And one has to get inside the head of the selecting official to really understand what goes into those decisions. And sometimes, you know, what comes out in the statements isn't the full picture. Generally speaking, there's been a big focus on where can humans go? What about extant life?

So I think that's, you know, been something that's been a challenge for Venus. But, you know, I was talking to an astrobiologist yesterday who's super excited about Venus. And she points out that, you know, the search for extant life is only one aspect of understanding habitability. You know, you asked me about Venus and Earth, can we call them twins? Well, they started out as twins. So to really understand how Earth evolved, how Earth became and remained habitable, if we can cannot explain how our twin went down the wrong path, then we don't really understand the conditions of habitability. Let's cover right up front, learning more about Mars as well, because you are, of course,

the deputy PI for the InSight mission. We are all very excited about that landing set for November 26th. We've kind of had geologists on Mars in the past, but this will be real geophysics, right? Is it going to help us not just learn about Mars, but about our own planet and Venus? Absolutely. Really, the goal of our mission is to understand how rocky planets evolve in their very early phases. evolve in their very early phases. All planets that are rocky, they start out molten from that incredible heat of particles smashing in together. What happens right after that phase

when there's enough material coming together to melt a planet? Very early on, in kind of a blink of a planet's age, tens of millions of years, it forms these layers. Every rocky body that's big enough has a core, a mantle, and a crust. We know very little about how that happened. Venus and Earth, their surfaces are so young that their crust is likely all recycled, you know, from that very early phase. The moon, which is the body that we've learned the most about this process of differentiation from, is tiny compared to Earth. The pressure at the center of the moon is something like the pressure at 300 miles down within the Earth. So in terms of what minerals form,

the pressure and temperatures and so forth, it's not representative of the full range of what we have on a big planet. You know, you look up at the sky, you see that beautiful white reflecting surface, that anorthosite, that feldspar that formed in these very early rapid differentiation phase when that new crust formed, that's not what it would have formed on the Earth. Going to Mars, which is a body that is closer in size to the Earth, to Venus, to Mercury, we'll be able to get a much better idea about that early process. What are the phase transitions that we can see in the interior of Mars? How big is the core?

Just learning about how big the core is tells us so much about the composition, because when you have that transition from the core to the mantle, there's only a certain range of compositions that can make that transition at that depth. Is the jury still out? And if it is, I'm sure Insight will help us answer the question about whether Mars is geologically, geophysically dead. There are different sources of quakes. You know, in terms of pure geologic activity, of course, most of Mars' geologic activity

happened in the first billion or so years. But there is a little bit of volcanism that's still geologically recent, you know, within a million, 10 million years. Blink of an eye. Yeah, yesterday. That's not very far from where we're going to be landing, maybe about 1,000 kilometers.

So we hope to see quakes from that system of faults that's nearby, from whatever's driving that volcanism. And really what's driving it is a mystery. The lithosphere, we think, is very thick. How does that volcanism occur? So we hope to get better insight into what's really causing that volcanism today. And this is why you're sending that exquisitely sensitive seismograph. Right, right.

And in addition to that kind of activity, planets cool with time. You know, we sent a seismometer to the moon, and we see evidence of that process of cooling of the planet, which causes it to contract and activate faults. So we expect to see some quakes driven by those kind of processes as well. I said seismograph. I should have said seismometer, right? Yeah, the graph is... No paper tape coming out. No, no. But, you know, Bruce Bannert, the PI for InSight, he does have a model of one of the lunar seismometers, which included a graph. I mean, it was a test model, but yeah.

Fascinating. I would have asked him about that if I'd known about that at the time. Speaking of dead planets, Venus, we've been told, I mean, it went from this lush tropical jungle to being a completely dead surface, not just devoid of life, but devoid of any activity, geophysical activity. Is this one of those myths that you told me a while back that you like to talk about? Yeah, well, you know, as we said, we haven't launched a mission to study the surface of Venus in about 30 years. And so much of the work that came out right after that mission, Magellan, has gone into textbooks and has sort of, in a way, kind of atrophied. This idea that Venus is geologically dead comes from a couple of observations about its impact craters. You know,

we use impact craters to tell us about the age of the surface. All over the solar system. Absolutely. And Venus has about a thousand impact craters, tiny number. Mars has hundreds of thousands of craters. There's some factors you have to consider, but it's a similar amount as to what we'd expect on Earth, you know, if we kind of extrapolate from land to the oceans and so forth. So in the same ballpark. What's really interesting about those craters is that they appear to be randomly distributed. So that suggests areas that aren't particularly younger or older.

And further, with the data we have, it seems like many of them are not modified. So you would expect if geologic processes were kind of in equilibrium with geologic processes, then a bunch of craters would be modified. And so these two observations of random distribution and very little volcanic flooding or deformation by faulting led to this idea that Venus catastrophically resurfaced. And then the impact craters were put down. And it's a fascinating idea from a geodynamical standpoint, how do you make that happen? From the standpoint of dumping a global layer, a kilometer thick of volcanism on the surface, that would cause huge climatic variations, you know, hundreds of degrees. So it's a captivating idea, but it's only one hypothesis. And in fact, recent studies have kind of shifted to being more consistent with ongoing geologic activity rather than catastrophic.

Ongoing, as in perhaps current day? You can fit a model that has resurfacing, say a volcanic patch, that's say within hundreds to a thousand kilometers in size, that's at an equilibrium rate. And that will also produce this random distribution of craters. When you say an equilibrium rate, it's just kind of spewing on a regular basis? Okay. Yeah, yeah. So as opposed to having this one massive event that filled up, that erased the surface previously. Instead, you can have a little volcanism here, a little volcanism there, and over the last perhaps 500 million years, you get the same effect as if you had a catastrophic event.

The reason it's so easy to fit many models is that there are so few craters. And then when you fold in geologic evidence, it's actually more consistent with ongoing volcanism. On Venus, we have these gigantic parabolas that form when a big impact crater forms. Basically, they're wind-blown, fine-grained material. And they extend up to about as much as 2,000 kilometers. Wow. Are these like dunes? Well, they're part of what's called the extended ejector blanket.

So it's basically when an impact crater hits, it spews fine-grained material up into the atmosphere. And because of Venus's super dense energetic atmosphere, that stuff gets lofted up pretty high into the atmosphere. And then the wind just carries it down out to about 2,000 kilometers. We haven't actually seen it be reworked into dunes, probably because the particles are too big. Oh, I see. Everybody listening to this show knows that the mantra at Mars used to be, follow the water.

Well, we found the water. Should we be following the water on Venus? Absolutely. So, you know, of course, there's no water at the surface of Venus. There's a tiny bit of water in the atmosphere. But it is possible, perhaps probable, that water could still be spewing as a gas from volcanoes. The pressure is 90 bars, so almost 100 times that on the surface of the Earth. It's hard to get gas to come out of rocks. You have to have quite a quantity. Some calculations have been done, in fact, by Lori Glaze,

to look at what would it take to get water to come out of a volcano. From her estimates of how volcanoes erupt and spew gas, it would take about four percent interior water, which is similar to water content in some lavas on Earth. So it's possible that water is still being added to the atmosphere of Venus. Again, this is one of these ideas that's sort of shifted in the last 25 years since we first got data from Magellan. You know, I and other people have published papers saying, oh, you know, we don't have plate tectonics on Venus because its interior is dry. And at that time, we thought most water came late from comets. We've had so much data from all kinds of bodies across the solar system that have, are at least starting, and in my opinion, have shifted this paradigm to the fact that planets form with the majority of the volatiles that they have. Basically, you know, the chondritic material

that forms rocky bodies carries that water and other volatiles that they have. Basically, the chondritic material that forms rocky bodies carries that water and other volatiles with it. In fact, we've had argon isotope data for Venus since the early days of exploration. That data suggests that Venus has lost less of its volatiles than Earth. We think Venus has outgassed about 50%, whereas Earth has outgassed about 75%. Wow.

So we think it's maybe deeper down than on Earth. And we learn more about how water is stored in the mantle of the Earth. It seems like every few months I see a new article about how a given mineral can store water in the interior of the Earth. So it's hard to really understand what's going on even on our own planet, but there's more and more reason to think that it's wetter inside the Earth than we thought before. Similarly, there's no reason to think that the interior of Venus doesn't still harbor water, and maybe in that rare, mighty burst of volcanism could actually spew it out into the atmosphere. This is exciting stuff. But so much of this is based on just extrapolation from old data now. I mean, what can we do, absent a mission, and we'll come back to that as well,

to help us understand what's going on on Venus? I mean, I'm thinking in particular of some work that you did with a couple of colleagues where you basically simulated Venus here on Earth. Yeah. What we were looking at is how does subduction start? So subduction is part of plate tectonics on Earth. It's where one plate is thrust under the other, as we have, you know, off the coast of Oregon and Washington. About this time, 50 years ago,

the theory of plate tectonics was coming into general acceptance. And one of the things that Earth scientists are really intrigued by is trying to understand how does Earth, how did Earth and how does any planet transition from a single plate, which all planets start out with, to plate tectonics? And so a number of theories have been put forward. One of the leading ones is that a hot mantle plume like Hawaii, where stuff comes up from the core and pushes up the strong outer part, the lithosphere, and creates volcanism, those plumes can actually lead to subduction. Define subduction a little bit better. Okay, so on Earth we have plate tectonics, and those plates are made up of what's called lithosphere,

the strong outer part of our planet where quakes form and so forth. They deform brittly. Subduction is where one plate, it goes into the mantle. Basically, it can either be pushed into the mantle by lateral motion of a plate, or it can simply sink into the mantle because they're actually more dense. And it's a shame people can't see your hands. We don't have pictures. But it's actually a layer can just be, as it's moving, it's just pushing it under another layer, another plate. Right, right. You know, when you're starting plate tectonics, you don't have that lateral motion of plates, right? The first step is actually to break the plates into smaller

plates. That way they have the ability to move around. And we think that subduction is really that process that allows plates to start breaking apart. These plumes can push the lithosphere up and crack them. You know, we have false form like that we think have led to plates breaking up on the surface of the earth, like in Africa and different places.

And so the plates get broken by the plumes pushing up on them and heating them from below, making them weaker. The volcanism, and sometimes it's massive volcanism like Siza Deccan Traps or the Columbia River Flood Basalts. When a plume first hits, you get massive, massive amounts of volcanism. That can cause another load on the surface. And between the load of that volcanism and the weight of the plate itself, because it's cold, it's actually more dense than the mantle below, they can start to sink. Okay. Yeah. I met Anne Devay at this conference, and she was actually modeling in her laboratory plate tectonics. And, you know, computer simulations can do many fabulous things, but laboratory experiments really can describe very accurately material behavior between these strong outer plates and what's going on in the mantle where it's convecting. She's done tremendous work in that area. And she had an example of plume-induced subduction. And it's incredible the similarity between what she sees in the lab and what we see on Venus. So she's actually doing this in a tank with a material that involves nanoparticles? Yeah. She's been

working with material scientists for decades, actually, to get just the right behavior in a material to simulate what's going on in a planet. Basically, you know, planets behave viscously. They flow like in the mantle. They behave plastically, so it kind of has a squishy deformation. And they behave brittly. On the Earth, when new plates form at mid-ocean ridges, hot materials coming up and making new crust at mid-ocean ridges, they start to cool as that plate moves away. And as that plate moves away, the cooling induces fracturing.

And this material that she has in the away, the cooling induces fracturing. And this material that she has in the lab, it does all of these things. Basically, when you expose it to air, it starts to become more solid and it dries out. And so the drying out process is like cooling, and it forms this lithosphere. And it sounds a little bit like what we have been seeing to the despair of a lot of people on the big island of Hawaii. There we're seeing it in miniature where this, the magma comes up and we see it crust over and crack apart. Yeah, absolutely. Hawaii is no longer a nascent plume. You know, we see that tail of material that's formed the other islands, you know, as the Pacific plate has moved across.

So that is not what we call a plume head because it's more like the plume tail. And so, you know, we see perhaps a dozen or so places around the earth where we think plume heads have hit the lithosphere. Like I was saying, the Deccan Traps and Columbia River flood basalt. So it's that amazing amount of volcanism that forms initially, we think. I would love to have seen or to see this work underway in the laboratory.

I've spent decades studying these features called corona on Venus. They're very enigmatic. studying these features called corona on Venus. They're very enigmatic. They are more or less circular features that have a whole slew of topographic shapes. Some of them are high, some of them are low. Many, many of them have these, they're like rims on the outside.

And there have been different models of how those formed. But in some of the largest ones, they form these rims and trenches that make like a, not a complete 360 degree circle around the outside, but just like a partial arc. People have actually proposed these to be subduction zones in the past. after the Magellan mission there were a number of papers written about subduction zones on Venus including by Dan McKenzie one of the founders of plate tectonics on the earth but these places also

have characteristics of plumes and people were like, nah it's not a subduction zone, it's got to be a plume and it's because of the work that earth scientists are doing to try to understand how does plate tectonics start that this theory of plume-induced subduction has developed, both with the work that Anne's doing in the lab and people have modeled it numerically.

And so what we see in the lab that completely explains what we see on Venus that hadn't really been explained before are these partial arcs. And now I really wish I could use my hands because it's a little bit hard to explain. But if you want to try this at home, if you take a piece of paper and you punch a pencil through it, you know, what you'll see are little flaps. Yeah. The lithosphere behaves like those flaps because it's brittle. behaves like those flaps because it's brittle. You know, it's not a viscously deforming material that can just smoothly sink with the lithosphere down into the mantle. But when the plume comes up,

it cracks the lithosphere. And then as the lithosphere tries to sink underneath the weight of the volcanism, it rips into flaps. What Anne sees in the lab is that you get these partial arcs where they form where they start to bend and they form a trench like a subduction zone and you don't get the full like circular trench because if you think about you know sort of a brittle material it it has a hard time bending around an arc sure. And so that it really explains some of the features that we see. And you said these are called coronae. Is there anything like them on the surface of Earth? No, no. And that's one of the mysteries. And I think that is likely a result of the fact that Earth's lithosphere today is cold and relatively thick. On Venus, because of its

massive greenhouse atmosphere, you know, I mean, because it's closer to the sun, it would be like 50 Celsius warmer than Earth. But because of its greenhouse, it's 500 Celsius warmer than the Earth. And so that makes its lithosphere thinner and more deformable. So that's one possible reason why we don't see these corona on earth. It may also have to do with the convection processes inside the planet. Some of them are quite small, and it's maybe that the temperature state or the layering inside Venus could be somewhat different. But it could just be the behavior with response to the lithosphere. It could be that these things are actually out there, but it could just be the behavior with response to the lithosphere. It could be that these things are actually out there, but we don't see them because our

lithosphere is too strong. But we don't know. If NASA came to you and said, Sue, we apologize. It's definitely time. What would you send to Venus? I mean, we have Akatsuki there now. Yes. Is it any help at all with any of this? Akatsuki and Venus Express do have, well, Venus Express had, you know, one micron spectrometers. The one on Venus Express was actually designed for the Rosetta mission in Europe. But then it was rebuilt and flown to Venus. Not exactly designed for that purpose. But amazingly, it was able to see the surface around one micron, basically see the surface brightness temperature. And it's a spectrometer.

So you're looking at light, but you're looking at the components of that light. Right, right. And so that's the thermal part of the spectrum. What we were able to do is derive surface emissivity. Emissivity is basically how a material gives off heat. Iron-rich rocks, which like basalt is blacker, tend to give off more heat than other types of rocks. It's really in that one micron region. It's really sensitive to the iron content.

Somebody out there now is thinking, aha, blackbody radiation. Yes. Not quite, but related. So what we were able to see on the surface, and this covered about 25% of the surface in good high signal-to-noise or reasonable signal-to-noise, we saw a number of locations where volcanic flows have a different emissivity than the surrounding material. We interpreted that for several reasons as recent volcanism. Basically, you know, if you've ever had the thrill of seeing flows erupt in Hawaii and other basaltic areas, they have this gorgeous metallic silver sheen when

they first erupt and crust over. Within hours, that silver color is gone. Basically, the atmosphere starts chemically interacting right away with that new rock. The same thing goes on in Venus. We don't know all the processes. We don't know the exact composition of the lower atmosphere. We can make predictions about what minerals would form when that new material is spewed out onto the surface. And we've made measurements of emissivity under Venus conditions. flows. We don't know how long it takes to go from fresh to weathered, but we see fresh flows. This is how we've interpreted it. And in fact, those flows so far have only been seen above mantle hotspots, which we knew of from Magellan gravity data. So, you know, we have reason to think that that's an active area from past data. This data from Venus Express suggests that it's chemically different, and stratigraphically those flows tend to be the youngest. So from these various lines of evidence, we believe that those are evidence of recent flows. And Akitsuki is also trying to find evidence of these types of flows as

well. I got to get to the big island someday. Okay, so tantalizing data, what would you send? It has been my dream to understand the difference between the evolution of Venus and Earth, and what that tells us about rocky planet evolution, about what to look for for exoplanets in terms of are we finding planets like Earth, planets like Venus. So I would send a mission to do high-resolution topography as well as radar imaging. And radar imaging, we've learned so much from, but it has its limitations on Venus because you need to have a difference from one body to the next in order to see it. So we could have two adjacent flows that are different in age and so forth, but we may not be able to distinguish the difference between them in radar.

When Magellan was sent 30 years ago, it was a fabulous data set, but we can do orders of magnitude better than that now. And topography is really a fabulous tool for studying a planet that we think is tectonically active. You know, we could map out the surface of the planet and really be able to see what's going on in these areas where, you know, from the radar, we can't really see much of anything going on. You know, and we could tell, have all of these impact craters been flooded by volcanism or not? We could see the topographic difference in craters that are more shallow.

A lot of them have radar smooth material in there. We're not sure if that's aeolian fill or sand that's blown in or volcanism. If we had the topography, we could see if these so-called dark-floored craters are actually topographically filled by volcanism, say, and that's actually 80% of the craters. If that is the case, the average age on the surface of Venus is more like 150 million years. Huh, pretty young. Yes, exceedingly young.

And we could use the same radar to look for active deformation. We could look at, we could observe these places that are believed to be subduction zones and actually see motion of the crust on Venus. And we would also take a spectrometer designed for the purpose of observing Venus. And we could see, you know, many more channels at much higher signal to noise, map the whole planet. You know, we've only seen this data for a small fraction of the planet so far. answer questions like, are these huge plateaus we see actually granitic, like our continents on the Earth? You know, continents on the Earth form when basalt melts in the presence of water. You know, Venus once had water. Are these remnants of that time when water was common on Venus near the surface. So, you know, there are

so many questions I would love to answer. And we can do so much now from orbit, you know, that we, I mean, there are fabulous things you can learn by going to the surface, but I would love to see us be able to do, you know, modern day global reconnaissance of the surface of Venus, and then really send landers to the most exciting places. So just to emphasize, a piece of the Holy Grail would be having something on orbit that could do kind of equivalent to what Mars Reconnaissance Orbiter has done, where it flies over a spot, and then it flies over again and says, oh my gosh, that changed. Yeah, I mean, there are a lot of parallels with data sets from Mars. I mean, we would do what MOLA, the laser altimeter, has done for topography. We would do sort of what the

context imager has done in terms of giving us global pictures. The mission I would love to send is aimed at getting a global view of Venus. So we would get high-resolution imaging. We would get the topography. We would get composition for the globe for the first time in multi-channels. And we would be the first mission to actually be able to detect active deformation on another planet, as well as active volcanism. We could use the same spectrometer to actually look for active volcanism, but it's hard to see because lava flows crust over really rapidly. So you have to get lucky. You have to see it within the first one or two weeks of it being active.

So we would look, but we would have to get lucky. I regret to say you proposed twice. You had a discovery program mission, didn't get funded. You reworked that into a new frontiers, a cheaper mission, didn't get funded. But you weren't alone. I mean, there were a whole slew of Venus proposals, and they all got ignored. What's it going to take? Well, that's an excellent question. and I wish I knew the answer. But, you know, I continue to talk about Venus, and more and more young scientists are really enthralled with the story of Venus and how it diverged from Earth. Exoplanet people want to know more about Venus.

They want to be able to apply models of how Earth has evolved. Hopefully we'll learn more about the atmospheres of exoplanets. But right now and into the future, what we have is information about their density, their mass, their distance from the sun. We have to be able to understand how the solid body is likely to be related to the atmosphere and to how rocky planets evolve so exoplanet people are excited about venus earth scientists everywhere that i talk to are excited about venus they they want to know what we can learn about the evolution of rocky bodies of how subduction start, plate tectonics might start. So, you know, I hope that we'll have a critical mass to really get the attention of all the right people.

We are with you on this at the Planetary Society. We have also noted that, you know, we have had a strong focus elsewhere in the solar system, but that there is much for us to learn at Venus. I certainly hope that this orbiter that you is much for us to learn at Venus. I certainly hope that this orbiter that you would like to get out there will happen. You already said there is a role for a lander. Do you see a time when we will once again go down to the surface of Venus,

which a lot of people don't realize has been done, was done several times by the old Soviet Union, and even once, what, for a few hours, I think, by a Pioneer probe that the U.S. sent. How important is it we get down to the surface, and do you think we'll be able to pull that off and maybe stick around for more than a few days before that spacecraft succumbs to that hell down there? Yeah, well, certainly it would be fabulous

to have landers on the surface. There are many questions we could address. Basically today, we could send a lander that could last for hours, but have much more sophisticated instrumentation than was done 25, 30 years ago. That in itself is worthwhile doing very soon. And, you know, we'd like to have information about the composition of the lower atmosphere as well. And then in terms of longer term missions, people are definitely working on technologies to make that happen, particularly high temperature electronics that could survive without cooling on the surface. And there's been a lot of progress, you know, I think there's much more work

to be done, but people do have concepts for very small landers that could last maybe up to a month. You know, we'd love to have a seismic network on Venus someday. You know, I think that's not imminent, but it's definitely an important scientific objective that people are working towards. I remember asking Bruce Banner when he was in your chair, the one you're in right now, wouldn't you like to send three InSight spacecraft to land on Mars? He said, of course, because then we could triangulate on stuff. Certainly seems like it would make sense to send a sophisticated orbiter before we go down to the surface again.

That is certainly how I see things. And just a little piece of historic trivia. In the very first call for Discovery missions, these new class of competed missions, some years ago, I was actually part of a mission concept led by Ellen Stofan, who has just taken the role as director of Air and Space Museum. Recently interviewed her right there, standing in the museum. Oh, very good. Excellent, excellent.

She put in a proposal to do seismology on Venus. Those were optimistic, heady days, and, you know, I think the proposal was about 15 pages as opposed to about the 150 pages that we put in now. But it's a very important scientific objective. Keep it up, Sue. Love to see this happen, all of us here at the Planetary Society would. And I'm sure that anybody who wasn't aware of how undead Venus actually is and how many mysteries are waiting there for us,

after hearing you talk about them, it probably feels the same way. Thank you for sharing all of this. My pleasure. Planetary scientist Sue Schmecker of JPL. Time again for What's Up on Planetary Radio. So the chief scientist for the Planetary Society is here in spirit, if not in person. That's Bruce Betts. He joins us every week to do this segment.

How are you? Hunky-dory, spiffy, keen, swell. How are you, Matt? I'm good. Part of the reason I'm good is we get so much nice mail from listeners, far more than we can read. Alicia Leach in beautiful Sausalito, California says, Because what's up? I was able to point out Jupiter, Venus, and Mars to my friends while camping in the Sierra this summer. Thanks for all you do, Beton Kaplan. Yay. And then this one, which may be the finest service we have ever provided with the show, Dominic Turley in Saskatoon, Canada. He listens to the podcast in the gym on Wednesdays. Wednesdays is ab workout night. So the show helps take my mind off of

the suffering. Funny, I think it just brings suffering to most people. Only my segment, just to be clear. We're here to alleviate suffering. So, all right. Take our minds off of our everyday troubles with

the ab workout and take us to the sky. Listen to me and I will remove all of your pain. I feel better already. You know what? Hey, did you check out any Perseids this last week? No, but I'm going to tonight because people will hear about this on the radio show before long. I'm going to an occultation of Pluto that ought to also be a good place to see what's left of the meteor shower. Okay. What?

Our friend Frank Marchese, the great astronomer, works mostly out of the SETI Institute. He is down in my area, the San Diego County area, and is going up into the mountains to observe this occultation of Pluto. It's going to occult a star. And I guess they're going to check out Pluto's atmosphere, what there is of it. And I'll tell you more after it happens. Well, there should be leftover Perseids. Those listening to this show might get some leftover Perseids. It's starting to thin out, meteors.

But there are always some meteors up there. But you can check out for a little bit longer the four planets I keep getting all excited about every week in the early evening sky, because, you know, it just, it doesn't happen that often. And we got going from west to east about starting, start half hour, 45 minutes after sunset, you got bright Mars. It's a little dimmer, but not a lot. It's still really bright and brighter than everything else up there except the moon. And then you come over to Saturn, yellowish Saturn, as you head towards the east. And then bright Jupiter.

And then super bright Venus that will be getting lower over the coming weeks. But it's good. Check it out. Check it out, Matt, when you're in the mountains. I will. And it really is spectacular. This week in space history, 1975, Viking 1 was launched. 1977, Voyager 2 was launched.

We move on to random space. That had kind of an alien quality. How do you know? So my word for it. So we just had the launch of the Parker Solar Probe, NASA's spacecraft to go touch the sun. Kind of, sort of. It'll fly through the corona much, much closer than any spacecraft has ever gone to the sun. It'll approach to within eight, well, a little less than nine solar radii from the sun.

Still really long ways, but not when you're flying by a big, giant ball of thermonuclear fusion. And we'll come back to that in the trivia contest. Ooh, ooh, ooh, ooh, ooh. Foreshadowing. Speaking of trivia contests, we've got two to get to the answers of, right? Right, Matt? We do because, you know, we allowed people to have an extra week for the contest that we announced on July 25th. And so both of those came due last week on August 8th, and we were going to go through the answers now. So we'll start with the oldest one, and I

asked you, when will be the next Mars close approach when Mars is closer to Earth than in 2018's close approach? How'd we do, Matt? A variety of answers to this, because I guess different sources had different answers, but the preponderance, the majority, said what we got from Ertan Yuzak in Phoenix, Arizona. He's a first-time winner. He says next closest approach that will be closer than the current one, the one we just had, will be in September of 2035. Does that jibe with your knowledge? That is definitely correct. All right, Airtown, congratulations. We are going to send you that Planetary Radio t-shirt and a 200-point itelescope.net astronomy account. Interesting, one date that was given by a lot of people, not really a date, a year, 2287. Ah, I remember it well.

Yeah, 2287 is when it will be closer than it was in 2003, which was the closest for tens of thousands of years. And the next time it will be closer than then is 2287. But the next time it will be closer than the 2018 close approach is 2035. And, of course, every 26 months it comes back to another close approach. But each of those will be getting farther away, then closer until we get to 2035. A number of fun responses from people, including Claude Plymate at the Big Bear Solar Observatory. He said, it's therefore no coincidence that the Planetary Society and others proposed

the first crewed orbital mission to Mars to leave in 2033, because I guess the alignment of the planets will be about right. Yeah, it's when you've got good opportunities and particularly favorable, closer Mars oppositions in 2033, 35, 37-ish. From Nathan Hunter, we hear from him a lot up in Vancouver, Washington. He says it's also in 2035 that Mark Watney will be stranded on Mars, and Cowboy Bebop's Jet Black will be born on Ganymede. Look it up. A related response. Daniel Kazard, who always sends us these great illustrations, customized illustrations based on

the contest, he's in the UK. If you squint, you might be able to make out Daniel and Elon Musk waving across the distance of just 35.4 million miles in 2035. That'll be a pretty good telescope and a pretty good trick. Dave Fairchild, our poet laureate. The Earth and Mars are pretty close. They're almost BFFs. They come about as close this year as they can ever get. So share a pizza pie with Mars. She's closer in the heaven than she will be until the date says 2287. So unfortunately, he had the wrong date, but it rhymes, so it works. It rhymed better that way. All right, let's go on to the next one. I asked you, what is the most abundant chemical element in the universe in terms of matter.

How do we do? We got a giant collective duh from our listeners on this one. Okay, Matt was wanting an easier contest. Maybe I went too far. No, I think it was just right. I think one like this is great now and then. It lets us, you know, it establishes a control group. That's what it does. Adam Kajokar. Adam Kajokar.

Adam Kajokar in Calgary, another of our Canadian listeners, he says, not surprisingly, it's hydrogen that makes up about 75% of the universe's mass. Of course, that's only if you don't include the dark matter. He means three quarters of listeners of this show, that means, are monotonic, tasteless, and highly combustible. They're listening to the show, so they're obviously tasteless. I'm not sure the other parts are valid. Thank you. Yeah, where is that? Wait a minute.

I got it right here. Okay. Adam, congratulations. He's a past winner, but it's been almost exactly two years since he last won the contest. He also is going to get a Planetary Radio t-shirt and a 200-point itelescope.net astronomy account. That's 74, 75% that we got from Adam. If you just talk about the baryonic matter, he says it's about 3.4%. So, you know, that's if you include the dark matter, whatever the heck that is. We got that from Mark Little in Northern Ireland. And finally, a poem.

Somebody trying to give our poet laureate a run for his money from John Jogerst in Navarre, Florida. Hydrogen is the simplest of all and came from collapsing inflatons in fields of flame. Some fused to make helium, an element new, and a few other metals came out of the stew, but the stars were required to make elements just like the oxygen and carbon in all of us. All this is nice, but elementary, my dear. What I want is that interstellar alcohol to put a kick in my beer. I'm glad you like it. I like that one too. We are ready now to go on. Back to the Parker Solar Probe. It's not easy to get to the sun, although you'd think it would be, but you got to bleed off a bunch of velocity or change your velocity vectors.

Never mind. Here's the question. How many Venus flybys are planned for the Parker Solar Probe to adjust its orbit so it gets closer and closer to the sun? Go to planetary.org slash radiocontest. And you have this time until the 22nd, August 22nd, at 8 a.m. Pacific time. And somebody out there who gets it right is going to win a Planetary Radio t-shirt. You can check them out at chopshopstore.com. That's where the Planetary Society store is at Chop Shop.

The 200-point itelescope.net account with all the great tools they make available. They just redid the basic tool you use to work with their worldwide network of telescopes, 200 points worth a couple hundred bucks. You can also give that, donate it to a school or a nonprofit if you choose. And we have another promo code for Distant Suns VR, the virtual reality version

of that long-proven astronomy program. It's only available for iOS, so for you iPhone, iPad users out there. It is terrific, and you can stick the iPhone in Google Cardboard or other VR viewing headwear and enjoy the universe that way as well. With that, I think we're done. All right, everybody, go out there, look up the night sky and make up your own knock-knock joke. Thank you and good night. Knock-knock. Who's there? Quark. Quark who? Charmed, I'm sure. That chuckle is from Bruce Batts, the chief scientist for the Planetary Society, who joins us every week here for What's Up.

Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its Venus-loving members. Mary Liz Bender is our associate producer. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan at Astro.