 And it's one o'clock on Tuesday, February the 1st, and you must be watching Science at Soast. I'm your host, Pete McGinnis-Marc, and for those of you watching the show in Hawaii, Gunghi Fat Choi, it's Chinese New Year, no less. This particular show is all about presenting research topics from the School of Ocean Earth Science and Technology, that's Soast here at the University of Hawaii at Manawa. And the whole objective of the course is to basically show what the students are doing in terms of their research. And hopefully we're getting a great diversity of topics. Last week we heard about ocean colour, and today our guest, Mali Chukov, is going to be telling us all about the regolith or the soil on the moon. So Mali, welcome. It's great to have you here, and we're really interested in some lunar studies. But first off, just tell us a little bit about yourself. You're a graduate student, as I understand. Yeah, I'm Mali Chertok. I'm a second year graduate student. I work with Paul Lucy here at the Kauai Institute of Geophysics and Planetology. And you are doing a PhD, and I understand that you're sort of just starting to put together research topics. All students have to get through comprehensive exams, and then they can focus in on research. And your particular area of research is on the moon. And in particular, you're talking about something called the regolith, and that's the theme of today's program. So Mali, where should we start? I think probably the first slide might be a good introduction. So Michael, if we can see the first slide, tell us a little bit. Why are we seeing both the ancient moon on the left-hand side and today's moon on the right-hand side? Yeah, absolutely. So something I'd like to sort of go into before we start is that the lunar soil is not like the soil we have here on Earth. The soil on Earth is sort of formed by original processes like wind and water, but the lunar regolith is different. The moon is an airless body, meaning it has no atmosphere. And so the regolith develops rather differently there. Regal means blanket and lith means rock. So it's not acting like the soils we have here where there's like layers of organics and horizons. Very much get like this fine powdery substance of the surface. So what we're looking at here is ancient lunar eruptions on the moon. And what happens is these eruptions get buried by regolith. And so actually we're not able to see these moribus salts, which is the dark parts of the moon that we see on the right and the moon today. Those are all covered by regolith. And of course, the image on the left is an artist's foundation. When we're thinking about the ancient moon, that's way before people on Earth or even the dinosaurs, right? We're looking way back early in the formation of the solar system would be my guess. Yeah, absolutely. So the moon formed about four and a half billion years ago. And so what we're seeing in that image is this like notion of late stage volcanism on the moon that occurred between four billion years ago and had a flux until about three billion years ago. And then, but there's been some volcanism since about until about one billion years ago. And that's billion with a B. And I understand that, you know, on Earth, Hawaii of course, Kauai is only five million years old, and probably the ancient continents on Earth, perhaps less than half the age of this ancient volcanism on the moon. So that we're looking really far back in time, correct. Exactly. We're looking really far back in time. The regular shields these things. So I think scientists sometimes find it a little annoying because you can't really see below it. But the regular this is sort of this fantastic timekeeper. It doesn't really keep track of time in a constant way it sort of keeps track of time in terms of the energy of solar system. So there was an impact flux billions of years ago at this point and there's still one but it's less so. So the regular develops because meteorites are barred the surface and grind things up kind of like a mortar and pestle. The impact flux you're talking about is the number of projectiles, you know, comments or asteroids that happen to hit the surface of the moon in any given unit of time. Right, exactly. And the moon has seen four and a half billion years of the solar systems history. And it's preserved in these impactors. So the regular is developing as these impacts hit the surface and grind things up and mix it and build it up. But what's really interesting is that the regular is sensitive to the energy of the universe. So when there were more impactors when the solar system was young, the regular felt really quickly. But now it's developing quite slowly. And in the right hand image of that first slide. We're looking at the near side of the moon. The dark areas you said are young ish volcanic flows. And right lighter lunar highlands and then those little pinpoints with sort of rays coming out from them. That's presumably an example of the meteorite impacts that you're talking about. Yeah, exactly. So these Mare units, the dark parts of the moon, you can see they're pretty circular. So there's from huge impacts and Mare lava's infill these basins. And it does an excellent job of preserving this. So these rate craters that you were pointing out are actually sample like these impacts are sampling below the subservice and exposing rocks at the surface. And they are of all different sizes, right. If that big circular dark patch, which I believe is Mario Imbian is over 1000 miles across. Some of the bigger things you can see from earth might still be 10s of miles across and they go really down to small sizes. Yeah, so there's some huge impacts that happened a very long time ago at this point, we really only see these smaller ones at this point. But the moon does an excellent job of recording these impacts like on earth, for example, we have a lot of erosional processes and plate tectonic and it wipes the surface clean every so often. So the moon is a super great natural laboratory for studying cratering. I believe in the next slide you've got an example we've actually seen just how thick, perhaps this lunar regular this can be if we go on to the second slide. Talk us through what we're seeing here Mali. Yeah, so this is the Apollo 15 landing site at Hadley real. What you're seeing on the left is an astronaut who is at the site probably taking measurements but on the right you're seeing these mar a lava flow deposits and on top of those deposits are is the regular that's been developing since it's in placement or since it's uncalled. Okay. And for further detail I think in the left hand slide that little rectangular black box shows where the more detailed image was taken. And so what we're looking at, it looks like a river valley, but you just said the moon doesn't have an atmosphere so what exactly is the astronaut standing in front of. I think it's a crater if I'm not mistaken right. Okay, well I thought you knew it's Hadley will. I know you're taking a course in lunar volcanism so maybe you've not seen that already. But yes, you're seeing the age of what was once a very active lava channel so that's, that's the idea and it's about 700 meters across and 300 meters deep I think at that stage but yeah. So that gives us a really good understanding that this layer of fragmented rock or regular as built up over an extended period of time. Maybe you can just help us better understand how does the rock get broken up that there's a particular sequence of events during an meteorite impact isn't there. Right exactly so. An impactor strikes the moon. Next slide, please. There we go. One through six. Right. What are we seeing here. Yeah, so we're seeing an impactor strike the lunar surface, and it's excavating material that excavated material is super interesting for what we want to understand about the lunar subsurface. The impactors have this super unique ability where they are able to sample below the regular and excavated material that we wouldn't otherwise see onto its ejected blanket. So if you follow the 12345 up until six you'll see this purple on the edge of the crater and that's the ejected blanket that contains really interesting information about the lava flows that were once under the that are under the regular now. And of course, you know, students can take whole courses in impact cratering mechanics as it's called. Any idea how fast these projectiles are hitting the surface of the moon or, you know, what their main processes are with them, you may not have taken classes yet on this. I'm just interested to know. I mean at this point I think it's kilometers per second. It's really high velocity impacts. The way I like to think about things that end up in the ejecta blanket is if I was a great picture which I'm not, I could throw a rock at a parking lot surface and let's say the parking lot is gravel. I could throw a rock and eject it onto the blanket pretty onto the impact blanket pretty well. But if it was like a asphalt surface and I was also a great picture and I was throwing this rock at the surface. It might just like crack it up a little bit. And so what we see in the ejected blanket is highly dependent on the strength of the subsurface. So, which type of material would be further if it hits a solid surface or if it hits a very fine dusty surface. Well, any ideas. Yeah, so I think if it's more unconsolidated like that gravelly surface I was talking about. I think things would be from further but also I think there'd be just more rocks in the ejecta blanket but if we were striking something more than something that like the asphalt parking lot, it would be much harder to break up and eject rocks. The impact would have to have a lot of energy. We saw on that original slide that the ejecta from some of these craters may extend tens or hundreds of kilometers away from the parent crater. And this ejecta blanket that you're talking about which is helping to form the regular isn't just right by the crater rim. It's going right way way out doesn't it. Yeah, yeah. Sorry. In that first image we were seeing we saw, I think that was Tycho, which is super bright raid and I mean it extends latitudes north and south so it's usually basically craters that sort of have a more confined ejecta blanket but this one is quite big. And Tycho is quite a young crater by lunar standards so it's fairly well preserved. Now, how do you study the regular? Jimmer in Apollo 15 could actually walk up and touch it but a graduate student in her studies, do you do laboratory work, computer simulation, how do you study the regular? So here on earth it's really easy. We see young lava flows such as those on the big island and we can look at those using satellite imagery a lot of the times are aerial imagery. But for the older flows we can just walk right up to them and and easily access them collect samples, but we really only have like six data sets in some ways to work with six Apollo landing sites. So we're really confined by the fact that we don't have a lot of what we call ground truth data. What I use is aerial imagery I use the lunar reconnaissance orbiter which I think is one of the slides I have. Yes, the next slide number four. There we go. All right. Tell us, it says it's NASA's lunar reconnaissance orbiter and there's two hours. Can you explain to us what the hours point to. Yeah, absolutely so NASA's lunar reconnaissance orbiter launched in I think 2009. And it's been orbiting the moon, it does great things. I use the camera called Elbrock. And I use that to count craters. And so that's how I identify my craters. There's another instrument on there that is a thermal imaging imager so it uses. It's called diviner. And so what we do with diviner is it makes thermal measurements of the surface. And it's actually able to detect rocks super well rocks retain their heat into the lunar night. So we can really easily identify these rocks versus these soils and constrain them and figure out how many rocks there are in a given pixel. I always hear the analogy that it's like you've got some calls in a barbecue and you heat up the barbecue. And then if you try and take the calls out they take an awful long time to cool down is that the equivalent of what you're telling us that diviner can measure. Okay, absolutely. And is it measuring the heat or the color or what where where do you get the information about how hot the rock is. It's measuring the heat and so actually what it's measuring is the in some ways the thermal inertia of the rock so how well the rock retains its heat and so it's able to make those measurements. And tell me how many for example how many rocks there are per pixel. And on the next slide I think we've got what looks like a garishly colored image with a crater in the middle. And then there's some images on the right inside. Explain to the viewers what exactly we're looking at here. So this is a very rocky crater and so this is the rock abundance data set, and it's overlaying on top of a, basically the cameras data set. And so what we're seeing is what diviner sees. So diviner. I'm able to find these anomalously rocky craters using diviner and I overlay these garish colors on top of the craters and the ejecta blankets and so what it's showing is that diviner accurately shows us that there are rocks in the ejecta when it says it has a high rock abundance value. Okay, and viewers might just be able to see on the right hand image that detailed our picture of the moon. There are some little blocks there. Roughly how large would one of those rocks be. If you can see it in the image, is it a few inches or is it a couple feet or 10 feet, do you know. It's probably a couple of meters. That's six to eight feet something like that. Something like that. Yeah, okay. That's absolutely cool. So if you've got this, you're developing this technique to find where the rocks are on the moon. That could be quite useful in the future I'm thinking, is it going to be useful where astronauts might land on the surface we're sending astronauts to the moon say in 2025 or 26. These boulders are big enough they might actually affect some of the landing sites wouldn't they. That's absolutely true and so diviner helps us choose these landing sites. We don't want to land in a boulder field. Not a good idea even the old strong didn't do that with Apollo 11 so it is part of your research then geared towards you that these future missions to the moon or is that a potential career development for you. I hope so I mean I would love to be a part of a mission in any way it can be eventually. But yeah these types of data sets would be really helpful and also create like, when you're looking at rock abundance you want to pick some pick a location that is super interesting and so when there's rocks in the ejecta actually might want to land sort of close by but not in the boulder field, you can collect actual rocks. Otherwise you're just on top of regular and then you're just looking at the fine grain stuff. An immediate question in my mind would be, so does all of the moon look the same, or do you find different areas with different rock abundances. Yeah, so part of my interest is in sensing different types of lava flows on the moon. And so we can do this by looking at the rock abundance in the ejecta and we're sort of trying to confine this mechanical strength of what's going on with these lava flows that are live beneath the regular. And so what we're seeing, and we have our final slide for that is, there's a huge difference between like Mario humor, which is super rocky you can see that has a lot of those garishly covered colored craters and then Mario and Taurus which is super barely rocky. So, and each one of those images that there's a scale bar in the bottom right so that's about 30 miles or 50 kilometers and they generally look blue. And if I remember the previous slide, blue means no rocks. Right exactly blue and then no rocks. Yeah, and then yellow and red means lots of rocks. Okay, so why, why do these two parts of the moon, which are both ancient lava flows. Why do they look different. Yeah, so that's what we're trying to understand and we have some ideas. So, for example, Mario humor, which is much rockier. Let's compare it to that gravel parking lot that we talked about earlier. So, maybe it's more unconsolidated, maybe there were a lot of bubbles in the flow and it's really foamy so impactors don't have to spend a lot of energy breaking up the rock then eject it because already quite weak. And then maybe marina Taurus is super confident. And so we're striking that asphalt parking lot where it's really hard to eject rock. But there's also something else that we need to consider and that's the thickness of the right list. Impactors can't actually reach the bottom of the regular then they won't eject rocks. But in the mara regions, it were pretty well can impactors can almost always excavate rocks, especially the more large the larger ones because the regular there's only about two meters or I think that's the height of a basketball player to like five meters which is the height of a giraffe. Now understand offline you told me that you're doing some computer modeling of lava flows is that intended to sort of understand how they might break up if hit by a projectile or where's that research taking you. Yeah, so if we can't exactly see the differences from the surface of these lava flows, maybe we can actually just can find their strengths. And so something I'm going to work on is modeling these types of things like, how does any flow react to impact versus something that is more like Poehoes but like really competent and doesn't have a lot of cracks and vessels. So, so that that's an aspect of your research coming up in the next few years what where do you see this particular type of investigation going and, you know, is you know a good place to do this kind of work. As a graduate student hopefully you're hoping to graduate soon and get a job. Yeah, training you well or what's your impression. Absolutely I as much as I love it here I don't want to stay here forever I want to get out into the workforce. So I. There's a lot of great mentorship opportunities here it's going to really take an advantage of we have excellent postdoc Emily Costello who's been an excellent mentor to me and she studies the regular mixing model and she looks at the development of the regular on the moon. We also have Shwylee, who works on constraining volatiles on the moon and so there's so many different things happening at so as to so I have a lot of, it's not difficult to find a mentor I would say. And you know the advice is Stoke Paul Lucy right to right recently won the Carl Sagan young investigator or something like that from NASA so it sounds like you're in good hands and so future jobs but what kind of thing would you be interested in if you move to the mainland or go international what what what's the goal. Absolutely for me first things first and that's to get a postdoc when I'm done. Okay. So postdoc and then I really hope to work on the mission in some capacity and so I hope that this research will propel me into that. Okay. Are there new missions coming along. Yeah, absolutely there's lots of exciting things. There's Viper just going to the lunar poles and it should be should be really interesting. And then I know offline there are other faculty members at UH are proposing to go to other parts of the moon with robotic explorers and of course the astronauts will probably go to the south part of the moon. Perhaps in four or five years time so that sounds really quite exciting. Would you have to work for NASA or university or are there commercial firms you might be looking at the job opportunities. Absolutely yeah there's some commercial options out there. I would just be excited to be a part of anything. So I think that it would be good to get that experience. Background. You know companies like Blue Origin and SpaceX are going to be sending their own landers to the moon in the next two or three years for example and it sounds like if someone like yourself can tell them that hey you know this is an area which is relatively bold or free. Then it's safe to land so that's that's sort of thing which might be really valuable so it's good to hear that UH is actually training you in an exciting field that may indeed provide a job for you which is good. Absolutely yeah. Good well anything else that you'd like to tell us. You're doing this computer modeling you're doing working with Divina. Yeah what classes do you have to take in order to learn about this research. Yeah so last semester I took a lava flow and rheology class and this semester I'm taking a lunar volcanism class. I'm really immersing myself into this volcanology aspect that I'm hoping will take me quite far. So I my degree I have a bachelor's in geology so I have a strong background in rocks but I don't exactly know how they work on planets on other planets so I think that being here has been really instrumental towards my development as a scientist. And I know there are problems with COVID doing into island travel but have you been to the big island to see the current eruption. I have actually yeah so we were on the big island in October for my lava flow and rheology class and we got to see the lava lake. It's really incredible. Can you actually tell the professor or the other students hey this is what you would expect to see on the moon with the same kind of geologic processes I presume Hawaii is a good analog to the moon but I should ask you if you think that's the case. I absolutely is I mean there's so many different volcanic features on earth and different types of volcanism on the big island alone so there has to be lots of different things that are happening on the moon as well. It's just on the big island and presumably it's a lot younger. Well my we're almost out of time. I want to thank you again. I know it's a challenge for any graduate student to come on the show and get quizzed by a professor. But it's really been interesting to hear about the studies of the lunar regular as well as some aspects of volcanism on the moon so thank you again for being willing to come on the show. Can we just remind the audience you have been watching ThinkPack Hawaii's Science at Soast. I've been your host Pete McGinnis Mark and please join us again next week where we'll have some other interesting aspect of research being conducted that you actually know. So until then goodbye for now.