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James De Buizer Talks About SOFIA’s New Zealand Observations

Season 1Jul 6, 2018

A conversation with James De Buizer, the science planning and instrument support manager for the Stratospheric Observatory for Infrared Astronomy or SOFIA.

James De Buizer

James De Buizer

A conversation with James De Buizer, the science planning and instrument support manager for the Stratospheric Observatory for Infrared Astronomy or SOFIA.

Transcript

Abby Tabor:Welcome to NASA in Silicon Valley episode 98. This week we’re talking with Jim De Buizer about SOFIA, our flying telescope that is currently studying the southern skies from Christchurch, New Zealand. Jim is the science planning and instrument support manager for SOFIA. He explains why SOFIA goes to New Zealand and tells us about some of the exciting observations the team has planned while they are there.

Now let’s listen to our conversation with Jim De Buizer.

Music

Host (Abby Tabor): So Jim, welcome, I’m excited to hear about your work with SOFIA. Who or what is SOFIA to start us off?

Jim De Buizer: Well SOFIA is the Stratospheric Observatory For Infrared Astronomy and it’s a heavily modified Boeing 747 aircraft that they have modified to put a 20-ton telescope in the back.

Host: Oh, wow. 20 tons.

Jim De Buizer: Right. So we fly this telescope at very high altitudes and I’ll get to in a minute why were you fly at high altitudes.

Host: Yeah.

Jim De Buizer: And then once we get up there, we open up a door on the side of the fuselage of the plane, it’s kind of like a rolling garage door and we peer out. And it’s about a 2.7-meter diameter telescope, which means the hole in the side of the plane is about 10 feet by 16 feet.

Host: Yeah, wow. So-

Jim De Buizer: So a rather large hole on the side of the plane, but it’s aerodynamically stable and it stays up and we observe space from high altitudes.

Host: Yeah. So when you say heavily modified plane to carry a telescope, you’re not kidding huh?

Jim De Buizer: That’s… That’s right.

Host: All right.

Jim De Buizer: So we find those high altitude because we’re interested in observing the infrared part of the electromagnetic spectrum and that’s beyond what your eye can see. It’s what we perceive as heat with our senses, and so we’re trying to look at the heat signatures of objects in space that don’t give off their own light.

Host: Okay. So it’s like the images you see with certain cameras, right? That show like the body and the hot spots on the body or-

Jim De Buizer: That’s correct. That’s correct.

Host: That kinda thing, yeah.

Jim De Buizer: The thing about the atmosphere is it absorbs infrared light-

Host: Oh, okay.

Jim De Buizer: That’s coming from space in the water vapor in the atmosphere.

Host: So you can’t see that down here. You have to get up above it.

Jim De Buizer: So you can’t see it from the ground.

Host: Yeah, okay.

Jim De Buizer: Right. So when we fly into the atmosphere, when we fly into the stratosphere, we fly above 99.9% of the atmospheric water vapor.

Host: Oh, great. Okay.

Jim De Buizer: So that gives a clear, unobstructed view of a large range of infrared wavelengths that are not able to be observed from the ground.

Host: Very cool. So that’s SOFIA.

Jim De Buizer: That’s SOFIA.

Host: And what makes SOFIA special. How did you end up working on this? Where did you come from originally?

Jim De Buizer: Well I got my PhD at University of Florida in 2000 in astronomy, and right after that I ended up taking a job in the foothills of the Chilean Andes-

Host: Oh, wow.

Jim De Buizer: Cerro Tololo Inter-American observatory. I was there for about four years and then got hired by another observatory called Gemini Observatory, which is a eight meter telescope that’s run by the U.S. Along the way I’ve always been involved in astronomical instrumentation. So I’ve been working on mid-infrared instruments my entire career from the time I was a graduate student working in the lab.

Host: I see.

Jim De Buizer: So I was involved at the level of working at these observatories, working on their instruments, helping astronomers take their data. And that’s why SOFIA said, “Hey, you know, We’re going to be flying our first light flight within about a year. Our first instrument is going to be a infrared camera, just like the one you’re using, or you’re working with, that Gemini. How about you come and help us get the first light?”

Host: Very cool.

Jim De Buizer: So I moved to California and had been based here at NASA Ames for about the last 10 years. And worked with the University of Cornell team that built the first light instrument for SOFIA to get it on the plane, get it working, get it, we get it commissioned on the telescope and get the telescope working and playing nicely with it. And I was involved in the first light science and it was very exciting time.

Host: Okay. So you’ve been on SOFIA from the start?

Jim De Buizer: Yes. I’ve been on it for a long time-

Host: Very cool.

Jim De Buizer: And I’ve transitioned a few years ago into science operations management and that’s kinda where I am now.

Host: Okay. And we wanna get to that, how do you plan the science.

Jim De Buizer: Yes. Another interesting topic.

Host: Yes. So we have Kassandra also from the SOFIA team here in the studio. You work on communications for SOFIA. Do you know all the backstories of your scientists like Jim?

Kassandra: I know some of them.

Host: Yeah.

Kassandra: I can’t say I know all of them. So I’m learning more about them every day.

Host: Yeah, it’s great to get to know the people.

Kassandra: Yeah. I’ve seen that first light image, it’s Jupiter. It was I believe the first thing that SOFIA observed and it’s really cool to hear the backstory of how the image came to be.

Host: Yeah, right. Did you think you’d end up Jim working in things like this? Were you a kid who played with telescopes and?

Jim De Buizer: Yeah. So as a child, I was always very interested in science and I grew up in a rather poor family. But my parents always for birthdays or Christmas ended up being able to get me a secondhand chemistry set or-

Host: Nice.

Jim De Buizer: Telescope or a microscope or something like that. You know?

Host: Yeah.

Jim De Buizer: And so they fed my science and I was always as a tween teen outside in the backyard with telescopes looking at things and I was – I really liked it. So yeah, I always kinda had an idea that I was going to be a scientist. I didn’t really know what direction it was going to go.

Host: Yeah. Yeah. But nobody was surprised when you went to work for NASA?

Jim De Buizer: I don’t think so.

Host: So have you flown on SOFIA then? Is that part of your job?

Jim De Buizer:Right. So I’ve – I’ve flown more than 50 missions on SOFIA.

Host: Wow.

Jim De Buizer: And I was on the vast majority of the first flight – the first several flights where we got the first light images and first science. And I was involved in reducing and analyzing and publishing that data, a lot of our imagery that Kassandra was talking about came from – coming off the plane, sleeping for two hours then frantically trying to create nice looking images to release-

Host: Wow.

Jim De Buizer: To everybody. So-

Host: Quick turnaround.

Jim De Buizer: Yeah.

Host: All right. What is it like up there that went to either of you, ’cause Kassandra, you’ve flown on SOFIA right?

Kassandra: Yeah. In some ways it’s similar to a commercial aircraft. It’s pressurized, you can walk around, there’s a seatbelt sign if it’s bumpy. In other ways it’s completely different. There’s all these computer stations to control the telescope-

Host: Okay.

Kassandra: And the instrument and guide cameras so you can see the star is that we’re looking at or planets or whatever it is that night. So it’s fascinating. It’s also a lot louder, colder.

Host: Oh yeah.

Kassandra: Yeah.

Host: Less climate control.

Kassandra: Well some of the instruments and maybe Jim can talk a little bit more about this, they need to be cold-

Host: Okay. I see.

Kassandra: So they keep the cabin cool, just to help keep the instruments cold.

Jim De Buizer: From the perspective astronomer, the plane is very similar to the control room of any other telescope I’ve worked at. I mean it has all the basic components. So after takeoff once you finally start like getting into the groove of taking data, it seems very, very familiar and you kind of forget that you’re on a plane until-

Host:Oh, really?

Jim De Buizer: As Kassandra said, you have turbulence and the pilot tells you to sit down and put on your seatbelt.

Host: Yeah.

Kassandra: We tend to fly through smooth airspace intentionally.

Host:Oh, okay. Right.

Kassandra: But sometimes it’s unavoidable.

Host: Yeah.

Kassandra:They tell us to sit down.

Host: Like any flight, I guess. Yeah.

Kassandra: Yeah.

Host: Is that part of your job Jim actually, to decide where the plane flies to do the science it needs to do?

Jim De Buizer: Yeah. So part of the science planning is to try to decide how we can get the most science inflight. And SOFIA is a telescope that is open access, which means astronomers around the world can apply to get their favorite targets observed-

Host: Oh, okay.

Jim De Buizer: And get data for whatever project they want. It’s a competitive thing. We get a lot more proposals for time than we can ever accept. And then it’s the plan – It’s the job of the science planning to basically find out how to efficiently create flights to get the most science for those astronomers.

Host: Oh, yeah.

Jim De Buizer: And it’s complicated by the fact that the observatory moves. It’s complicated by the fact that the observatory has a telescope that only looks at one side of the plane. This 10 by 16 foot hole I was telling you about-

Host: Right.

Jim De Buizer: Is off the left side of the plane. So that telescope has some movement up and down. It can move from about 30 degrees above the horizon to about 60 degrees above the horizon.

Host: Okay.

Jim De Buizer: But if I’m looking at target in the east and suddenly I want to look at something in the south, you have to turn the entire plane-

Host: Yeah.

Jim De Buizer: In order to point to that. So that means we’re flying in one direction for somewhere between 40 minutes to three hours usually, is how long we stay on a single target observing, analyzing it, and then we have to turn onto a new leg. And then we have to try to figure out how to put all these legs together so that we take off where we – or we land where we took off-

Host: Oh, right.

Jim De Buizer: Which is at the Armstrong Flight Research center, so.

Host: Here in California. Yeah.

Jim De Buizer: Here in southern California. Yeah. So it’s a complicated issue and it requires a fair amount of computation, a fair amount of manual labor – but we do it and it’s a-

Host: Yeah.

Jim De Buizer: It’s a very interesting process.

Host: So what could be a typical path and how does that line up with the science that you could do? Is there a typical-

Jim De Buizer: There is no – I wouldn’t say there’s any typical path. We can’t fly over Mexico, we’re not cleared to do so, but we can fly over Canada. So we typically… I’d say if there’s a typical thing, we typically fly either east to go over the continental U.S. or west into the Pacific. Now, one of the reasons – Well we’ll get to this in a second about New Zealand, but in the summers in the U.S., flying over the central Midwest of the United States, you have a lot of thunderheads, you have a lot of a storm clouds type situations-

Host: Yeah.

Kassandra: Turbulence.

Jim De Buizer: And we get a ton of turbulence.

Host: Okay.

Jim De Buizer: And so we often – Often these cloud heads can be so high that they can actually be in our way and air traffic control will route us around it, which means we have to stop observing objects in order to be safe. That’s one of the reasons why we go to the south, go to the New Zealand during our summer, is that a down there in New Zealand, it’s not summer.

Host: Right.

Jim De Buizer: And they don’t have the same kind of a weather issues-

Host: Okay.

Jim De Buizer: That we have here.

Host: So it’s better for SOFIA to fly in the winter, wherever that may be.

Jim De Buizer: Yes, there is multiple reasons why it’s better in the winter, the air is drier. In the winter, your skin gets chapped and stuff-

Host: Yep.

Jim De Buizer: Because they can’t hold as much moisture. So the air is drier and that’s good for infrared astronomy.

Host: Right.

Jim De Buizer: As I said-

Host: That was the whole point. Right?

Jim De Buizer: The whole point is to get above the water vapor, so.

Host: Right, exactly. So you guys are about to leave for New Zealand, aren’t you?

Kassandra: We are. At the end of May, we will be heading down. I think actually SOFIA might officially leave in early June, but some of us go down a bit early to be ready.

Host: Yeah.

Kassandra: Yeah.

Host: What’s it like down there, because people here in New Zealand and we all think, “Oh, so lucky.” But you guys are hard at work under kind of extreme conditions, aren’t you?

Kassandra: Yeah. Well it’s very dark, which is another good thing for SOFIA. We fly at night, so we have really long nights. Cold, dry. The nice thing about New Zealand though is it’s very cold and dry where we fly, but on the ground it’s actually a pretty moderate climate considering it’s winter because there’s such a close proximity to the ocean. So that keeps everything pretty moderated considering how far south we actually are.

Kassandra: And we’re operating out of a commercial airport. It’s tech… We are at the U.S. Antarctic programs facility and it’s shared – like the runway with Christchurch International Airport, it’s connected. So the U.S. Antarctic facility is kind of off to the side, but we end up taxing out next to all the commercial planes.

Host: Oh yeah, that’s really-

Kassandra: So that’s really different from what we offer – how we operate here, where we kind of have our own NASA facility out in Palmdale. So sometimes I think from what I’ve seen in the past, is there a time where we really need to take off ’cause our flights are our planned down to the minute or even sometimes the second.

Host: Oh, wow.

Kassandra: And they want us to take off maybe a few minutes early because if we wait then a commercial airplane is gonna taxi out and we’ll get stuck behind them and then we’re too late.

Host: Oh, wow.

Kassandra: Is that right, Jim?

Jim De Buizer: That’s right.

Kassandra: Yeah. So that’s kind of an interesting factor that gets-

Jim De Buizer: Yeah.

Kassandra: We have to account for in New Zealand that we don’t have to.

Host: Interesting.

Kassandra: Yeah.

Host: So that just shows how many details you guys have to think about. So it’s really precisely timed these flights.

Jim De Buizer: Yeah. If we get off ground track from the outset like that by more than a handful of minutes, we can be chasing our objects all – losing time on our objects all night long, just because of the-

Host:Oh, yeah.

Jim De Buizer: The nature of the – the way the sky turns and how long targets are up and how long they’re available to us and-

Host: Right.

Jim De Buizer: Yeah, it’s very important that we take off on time.

Host: I see.

Kassandra: Right. Because if we take off – If we’re off time, then the object could be too high or too low in the sky for us to see. Is that right?

Jim De Buizer:Yeah, it could be rising or setting, which means it will go below that… There’s elevation limits that I told you-

Host: Yeah.

Jim De Buizer: The telescopes are capable of doing.

Host: So Kassandra, you said something earlier about, different things you see in the southern hemisphere. Can you remind us how that works? What’s different than there?

Kassandra: Well it’s, you can see different stars, in a different part of the sky. The Southern Cross is very high in sky, the farther south you go. We can’t see that here.

Host: That constellation, yeah.

Kassandra: But things like the North Star, can’t see that down there. We can also see other galaxies, satellite galaxies to ours, the Large and Small Magellanic Clouds

Host: That makes sense.

Kassandra: We do observations of those frequently from New Zealand.

Host: All right. Cool.

Jim De Buizer: Yeah, being somebody who grew up looking at the sky with a telescope in his backyard in the U.S., and then having lived in Chile for almost a decade, I really feel that the people who live in the Northern Hemisphere got really jipped.

Host: Ah, really.

Jim De Buizer: There is some miraculous objects in the southern skies that you can see with your naked eyes, that you can’t see in the Northern Hemisphere. Kassandra alluded to a couple of them. I think one of the most fascinating things, and I used to spend time on the summit in Chile outside just staring up at them, the Magellanic Clouds are just amazing.

Host: What are they again?

Jim De Buizer: These are two galaxies that are actually galaxies that are in orbit around our own galaxy. I think the vast majority of people who live in the Northern Hemisphere don’t even realize that we are these satellites that constantly in rotation around our own galaxy, because they don’t see them in the Northern Hemisphere. They’re our closest galactic neighbors. In terms of people who want to study galaxies, you can’t do anything better than these really, really close galaxies that are going around our own galaxy.

Host: yeah

Jim De Buizer: Now when I say they’re going around our own galaxy, you can’t see them moving. They take hundreds of millions of years to go around our galaxy. But they are gravitationally bound to our galaxy, and they are maybe about a tenth of the mass of our own galaxy. Sorry, I mean a hundredth the mass of our own galaxy, and about tenth the size. But they’re really interesting environments. You can see them with your naked eyes. They look like clouds, in the sky.

Host: That’s cool. I never felt bad about my life until now for being –

Kassandra: Realizing we’re missing out on so much.

Host:Man.

Jim De Buizer: And then the other thing is the Galactic Center of our galaxy is – In the Northern Hemisphere, it gets barely above the horizon. It can be hard to see, especially if you live in an area where there’s city lights that make the horizon glow. In the Southern Hemisphere, the Galactic Center goes right above- over your head. It’s this view of the sky where it’s almost bisected in half by the Milky Way, this gorgeous line of stars. Then you have the really dark coal sack where there’s no stars, that you can see with your eyes, where the center of the galaxy is, right above your head. It’s absolutely gorgeous.

Host: Amazing. You know I was in Chile not too long ago and I was waiting to see something like this, but it was the full moon. I missed it.

Kassandra: Oh, so it was too bright to see the stars.

Host: Yeah. So can you see things like this in Christchurch, where SOFIA flies from?

Kassandra: Well it’s a city, so there is some light pollution. But if you go out into the country, like far out away from the city, you can see a spectacular sky. SOFIA ends up flying quite often very far south, towards the south pole, and we’re over the ocean. It’s very dark, and just put your face against the window on SOFIA, and look out. Yeah.

Host:You must see as many stars as a person could possibly see anywhere.

Jim De Buizer:Actually, the problem becomes with if you’re looking with your eyes, not science instruments. But if you’re looking with your eyes, we go so far south towards the Antarctic Circle that we get very bright aurora –

Host:Oh, no way.

Jim De Buizer: – that fill the entire sky. It’ll make it very difficult to actually see the stars.

Host: Man, that’s such a problem.

Kassandra: They are beautiful though. We don’t observe aurora, but it’s a nice little side show for us.

Host:Side show. Exactly. Oh, that’s fascinating.

Host: You just mentioned instruments. You said there are different instruments on different flights of SOFIA, right? How do they choose what’s gonna fly?

Jim De Buizer: That’s right. That folds into this science planning. Once we know the observations that we want to take for the astronomers for the year, we try to use our computer models to find out what times of the year are best for observing objects in that pool of targets. We can only have one instrument on the telescope at a time. By doing this complex calculation, we can find out when’s best to put each instrument on.

Jim De Buizer: And for the southern deployment to New Zealand, we have chosen two instruments. The GREAT instrument, which is a German spectrometer that observes it far infrared wavelengths, and we have the HAWC+ instrument, which is a far infrared polarimeter.

Host: Polarimeter.

Jim De Buizer: Yeah.

Host: What’s that?

Jim De Buizer: So a polarimeter is a specialized type of instrument that can analyze the light in a way that gives you information on what is happening in the magnetic fields in an object, so their orientation, their structure.

Host:Do you visualize a magnetic field? Do you see a magnetic fied?

Jim De Buizer: You can actually see a magnetic field once you’ve analyzed the data from a polarimeter.

Jim De Buizer: That’s one of the reasons why we’re bringing HAWC+ down to the Southern Hemisphere. These wavelengths that we’re looking at with HAWC+, this is our first opportunity to ever look at them with a polarimeter.

Host: Those wavelengths, those particular wavelength of light or some particular source?

Jim De Buizer: Those wavelengths. Yeah.

Jim De Buizer: Right. Well, it’s our first chance to observe targets that we want to understand the magnetic fields around, including the Galactic Center, star forming regions that we can see from the Southern Hemisphere, and this is our opportunity to do that with HAWC+.

Host:What will you learn by knowing about the magnetic fields about the Galactic Center? What will that tell you?

Jim De Buizer: In the Galactic Center, there’s a interesting interplay in terms of things are spiraling into the black hole in the center of our galaxy. But there’s also supernova that have gone off, that have cleared out areas, but is also star formation. All that in some way, is either affected or directed by the magnetic fields. And so by understanding what the magnetic field orientations and geometries are, we might be able to understand those processes more.

Host: Oh cool. Neat. Then the other instrument, GREAT, you said.

Jim De Buizer: Yes. So GREAT is a spectrometer.

Host: Yeah, what are you looking at?

Jim De Buizer:That’s a way of analyzing light form a object to find out what its chemistry, what it’s made out of, and also what the dynamics of the materials is in a target. What I mean by that is, we might look at a far off star with the spectrometer, and find that it has a circumstellar disc around it because we can see emission from it from molecules that we expect to be in circumstellar discs, and we can actually also see them rotating around the star. So we can get chemistry and we can get dynamics from an instrument like GREAT, just by analyzing the light.

Host: Wow. There’s so much information in light. That always gets me.

Kassandra: Yeah. I’ve seen an image, and it was a periodic table. Each element had its own, what they call spectral lines. Basically it’s own light fingerprint. That’s what GREAT’s analyzing, right Jim?

Jim De Buizer:That’s right.

Kassandra: Yup. It can tell you what molecule’s there, how fast is it moving, and in what direction.

Host: Yeah. Wow. What are you looking at with that exactly?

Jim De Buizer: So with GREAT, the targets are similar. We want to look at the Galactic Center. We want to study the actual material spiraling into the black hole and see, you know, how it’s doing that, what its structure and its orientation is, as it spirals into the central black hole of our galaxy.

Host: Is that why HAWC+ and GREAT are the two instruments on this deployment? Are they working together to answer questions about the same targets?

Jim De Buizer: In this regard, with the galactic center, it will be a nice complement to each other to have GREAT and HAWC+, where one is looking at the chemistry and dynamics, and the other one is looking at the magnetic fields that will give us a very complete picture of what’s going on in the Galactic Center.

Host: Neat.

Kassandra: I think we’re also have plans to make a new map of 30 Doradus, or the Tarantula Nebula, is that right?

Jim De Buizer: Right. These Magellanic Clouds are the Large Magellanic Cloud and the Small Magellanic Cloud. In the Large Magellanic cloud, there is a very active star forming region called 30 Doradus, which is also known as the Tarantula Nebula. This is a site of a lot of ongoing star formation. Astronomers are interested in this region in particular because the Magellanic Clouds have what we call a very low metallicity environment. What do we mean by that?

Jim De Buizer: At the beginning of the universe, almost all the universe was hydrogen and helium. It took the formation of that helium and hydrogen into stars. And inside those stars, different processes created oxygen, and carbon, and nitrogen, and heavier, and heavier, and heavier elements that all happen in the processes in the bowels of stars basically. And when stars die, they blow that material over, and it gets incorporated into the next generation of stars, and then the next generation of stars. So with every passage of a population or a generation of stars, we get more enrichment out of the interstellar medium. That goes into the next population of stars.

Jim De Buizer: So the Milky Way has a certain metallicity. The Magellanic Clouds have a much lower metallicity. By studying star formation in the Magellanic Clouds, we can actually study them as a proxy for what star formation was like in the early universe, when the metallicities were naturally in all the universe, much lower.

Host: Okay. Before those elements built up.

Jim De Buizer: Before they built up and really enriched the interstellar medium like they have in the Milky Way. This is a way of, we study the Large Magellanic Clouds and the star formation within it. We study the star formation within our own Milky Way and we try to compare how do those environments affect how stars form, and how they affect the next generation of stars. Which is really, really cool.

Host: It certainly is.

Kassandra: Yeah. So we’re getting to how the universe started, how stars like our sun formed. We’re studying how new large stars are forming, and that can tell us how stars like our sun form, or other smaller mass stars in some cases.

Jim De Buizer: Yeah, was star formation more efficient when metallicities were a lot lower? Did massive star formation have the same effects on the feedback on the environment as in our own galaxy?

Host:Yeah. So you understand better how these systems form, where they might be going, perhaps?

Jim De Buizer: And star formation in general.

Host: Yeah. So you’ve mentioned star formation, we’ve talked about black holes. Other exciting things that seem really different, one from the other, and all super interesting. That’s what I find fascinating about this work. You guys do so much different science.

Jim De Buizer: We haven’t even talked about one of the coolest things that is not visible with your naked eye in the Southern Hemisphere, but is the brightest infrared object in all of the sky, that isn’t a solar system object.

Host:What is that? What is it?

Jim De Buizer: That’s the object called Eta Carinae. And so Eta Carinae is this very, very super massive binary star that is old. The primary of most massive star, of the binary, is about 200 times the mass of our sun. Its companion is about somewhere between 30 and 80 times the mass of our sun.

Host:Oh wow. They’re huge.

Jim De Buizer: They’re both, super, super huge. The primary is getting very, very late in its life where the thermonuclear energy in its core is not very efficient anymore, and it’s puffing up, so that its outer layers are just barely being held on by gravity.

Jim De Buizer: Stars stay together between two forces, gravity pulling the material down and heat energy trying to puff it up. These stars like this one are so unstable that they actually erupt where something will happen inside the star, and the outer layers of the star will basically explode and fly off.

Host:Oh wow. Is that anything like the sun does with solar flares, or something?

Jim De Buizer: Much, much larger scale though. The primary star, which I told, is about 200 solar masses now, lost about 30 solar masses of material in one eruptive event in the 1800s.

Host: Oh wow.

Jim De Buizer: It became so bright from that eruption that people could see it as the second brightest star in the sky, in the 1800s. And over the course of weeks, it started fading away, and faded away from being a visible star altogether. But since then the material has grown and expanded. The outer layers of that star have ballooned out, they’ve cooled down, larger molecules have condensed out of that material, dust has condensed out of that material. And now it’s this huge nebula that is so bright, and being heated by this very, very hot massive star that we see it as this super, super bright thing in the sky.

Host: Wow.

Jim De Buizer: And since 1940 it’s started getting brighter and brighter, and so it’s an interesting target for us. What we’re specifically going to do on this flight series down in New Zealand when we observe Eta Car is, we’re going to look for signs of eruptions that happened prior to this great eruption in the 1800s. There are very thin shells of material that have come off of the star in earlier epochs, and by looking at those shells we’re looking basically back in time at earlier events and with GREAT we can look at the chemistry in these shells.

Jim De Buizer: And by looking at the different shells we can see how the chemistry of these shells evolve over time, how the dust forms out of it, how the denser molecules coalesce out of that material that came off of the star.

Host: That’s crazy. It sounds like you’re describing the thinnest little eggshell of dust, how far away around another star? And you’re able to see that and learn from it. That’s crazy. Awesome. So that’s super far away, right? Do you have SOFIA studying anything in the solar system closer to home?

Jim De Buizer: Eta Car is about 7500 light years away. So, yeah it’s in our own galaxy. Or some of the Magellanic clouds, they’re more like 200,000 light years away.

Host: Oh wow.

Jim De Buizer: But those are our closes satellite galaxies. Andromeda, which is our closest galaxy that’s a big galaxy like our own, is something like 2.5 million light years away. So if you want to come closer to home we do have probably the closest object that we’re going to be observing is Titan, which is a moon of Saturn. And what’s going to be cool about this is we’re going to observe Titan in what we call an occultation. An occultation is an event that’s kind of like an eclipse. It’s when a body in our solar system moves in front of a star and sort of extinguishes the light from that star. We can learn a lot about an object from it moving in front of a star. If we have something like an asteroid that doesn’t have an atmosphere at all, when the edge of the asteroid reaches that star, the star’s light winks out completely and just kind of drops immediately.

Jim De Buizer: If we look at an object like Titan, where it has an atmosphere, as the outer edges of the atmosphere start to go in front of the star the light gets scattered out of the path of light that’s coming to you, and so it gets dimmer, and dimmer, and dimmer as it goes into the deeper and deeper parts of the atmosphere. So rather than having a quick drop off of light, light slowly declines. And so we study that decline of the light and that tells us a lot about, one, how high the atmosphere is, and how thick the atmosphere is.

Host: Right, right.

Jim De Buizer: And the interesting thing about Titan is, Titan is thought to have seasons just like the Earth has seasons. And they would like to know does the thickness of the atmosphere, does the height of the atmosphere of Titan change as a function of the seasons?

Host: Oh, okay.

Jim De Buizer: And so that’s one of the things that we’ll be doing – this occultation experiment on Titan.

Host: Yeah, like an eclipse?

Jim De Buizer: It’s like an eclipse.

Host: It’s Titan eclipsing some distant star that you’ll choose, right?

Jim De Buizer: Yeah, but it’s actually — unlike an eclipse of say the moon. When there’s a lunar eclipse you see it basically over most of the earth. And when you have a solar eclipse you see it over a very small path of totality, right?

Host: Right. Like we saw last summer, right? Yeah.

Jim De Buizer: So for Titan, which is a much smaller body, and it’s eclipsing this star. You can imagine that the path of totality of Titan is very, very tiny. So we’re talking you know hundreds of miles – dot, that is going across the surface of the earth at close to 100,000 miles per hour. And so we’re in SOFIA flying at Mach .85, which is about a little less than 600 miles per hour, and we have to try to intercept that shadow as it’s crossing the face of the earth. And we have successfully done it with Pluto. We’ve successfully done it with Triton. We have successfully with a Kuiper Belt object called MU69, which was only thought to be 30 kilometers wide, which is a very, very tiny target.

Host: That is crazy. How big can that shadow be when it reaches us?

Jim De Buizer: Very, very small.

Kassandra: We had what? Like two second for MU69. The New Horizons target.

Jim De Buizer: For MU69 totality was one and a half seconds, yes.

Host: Oh, my gosh! So, you can’t afford to miss any fraction of that?

Jim De Buizer: No, you can’t miss it.

Host: Wow.

Kassandra: And ideally with any of these shadows, but particularly when it’s bigger, we want to be in the center, right? Like we don’t want to catch the edge, so that further complicates the timing.

Jim De Buizer: If you get it right in the center then you also get the best idea of what the diameter of the target is, or how big the atmosphere is. If you’re off center then you’re bisecting it only through part way, so you’re not getting the size of the object, or you’re not getting the full height of the atmosphere.

Host: I see. Yeah.

Kassandra: But that’s the bonus of being on SOFIA is that we’re moving, and they work to calculate where the center is, and then we fly through it.

Host: Fly right through it? Right.

Jim De Buizer: Yeah, we have a satellite phone onboard the plane, and there will be people who are actually taking data up until moments before the occultation event, and feeding us updated calculations of where that shadow is going to be on Earth.

Host: Oh, really?

Jim De Buizer: And we have to, in real time, work with the pilots to correct our course and try to intercept the shadow when we can.

Host: Oh, my gosh.

Kassandra: Yeah, and there’s winds. And so the winds can slow you down, and then they can start speeding you up. And so one of our mission directors is sort of monitoring our planned path, and then where we’re supposed be, and working with the pilots like, “Oh, we’re getting ahead of our plan. Oh, we’re behind it.” And so they kind of adjust our speed to keep us right on to the second, and get that center of the shadow.

Host: Is it really hectic in these final moments just before totality? Calculating? Quickly changing?

Jim De Buizer: Yes, it’s a high pressure situation for sure.

Host: Yeah. How exciting.

Kassandra: Yeah. I was on the MU69 flight sharing some updates on social media. And I was listening into the pilots, and the mission director, and the scientists, and this debate over, “We’re too slow.” “Now, we’re too fast.” We have to get there, you know, at the second because, I think with Pluto we had, what? 90 seconds?

Jim De Buizer: About 100 seconds of totality with Pluto, that’s right.

Kassandra: So, it was a larger object, larger shadow. But MU69 was so small that was had a very small window of time. But Titan’s big so it should be a little less nerve wracking. It’s not one second.

Host: A little more leeway there?

Kassandra: Yeah. Do you know how many seconds we have for Titan, Jim?

Jim De Buizer:I don’t actually know. No.

Kassandra: Okay. I would imagine it’s-

Jim De Buizer: It’s going to be of the order of Pluto.

Host:100 whole seconds. What are you going to do with all the downtime?

Kassandra: It’ll be a luxury.

Host: Right? Totally. That’s so cool. Wow.

Jim De Buizer: The other thing that we have in The Southern Hemisphere, that we’ll try to observe, is Supernova 1987A. This is a supernova that went off in 1987, hence the name. But it was in a large Magellanic cloud, and so it’s one of the closest supernovas that have gone off in our lifetime. And what’s great about it is, because the large Magellanic clouds are so close we are watching the evolution of the supernova remnant, this material that got blown off of the star in the supernova, we’re watching the evolution of it happen over the last several decades, and SOFIA is going to contribute to that study. It’s been monitoring it for several years now, but they’re also going to try to observe it on this New Zealand trip as well. And so it’s really cool because you can watch the dust forming out of the ejecta, you can watch it moving out in sort of this shock front in all directions, this sort of circular shock front. It’s hitting previous material that existed in the surroundings, and it’s lighting up like fireworks in the places where it’s hitting the surrounding clumps and stuff in the medium.

Jim De Buizer: And it’s just a very cool thing to be able to witness because supernovae are usually very, very far away. They’re usually in external galaxies very, very far away and so we don’t have this kind of ability to see them in this kind of detail. And so we’re very lucky to be living at a time where one just went off and we have the instrumentation to resolve — to see the structure, to see it at this kind of resolution and watch it change.

Host: Yeah.

Kassandra: Because we observed this supernova last year as well, right?

Jim De Buizer: I think we’ve observed it every year we’ve gone down to New Zealand so far. With different instruments, but –

Host: Yeah. So you get to see it changing?

Jim De Buizer: Yeah, you get to see it changing. And I’m part of one of those programs where we have been monitoring it for a couple of decades now. And you watch how it all changes as a function of time, and it’s very cool.

Host: Yeah. That is really cool because I think of a lot of astronomy as like static, you know? Because I see photos of celestial objects, whatever. But to think they’re out there changing, there might be seasons on Titan and you can observe that. That’s very cool.

Jim De Buizer: That’s another strength of SOFIA. I talked about how you have to get above the atmosphere in order to see these wavelengths. Prior to SOFIA, and a couple of other small airborne missions, mostly infrared has been explored through satellites. And satellites have a very limited lifetime because of cryogens. They need cryogens to keep their instruments cold.

Kassandra: It’s like liquid helium, liquid nitrogen, right?

Jim De Buizer: That’s right. And we didn’t actually talk about that. We have cryogens on our instruments as well. If we’re trying to see the heat signatures of things in space our instruments need to have as little heat coming from them as possible in order to see those heat signatures.

Host: Oh, of course.

Jim De Buizer: So we cool them to just a few degrees, or sometimes milli Kelvin above absolute zero.

Host: Oh, wow. That’s possible?

Jim De Buizer: Yes. Yes, fractions of a degree above absolute zero in order to see these heat signatures. So those satellite missions in the past have run out of cryogens after three or four years, and then they can’t observe in the infrared anymore. So, not a lot of study had been done in these wavelengths in terms of variability over time of astronomical objects. SOFIA has a 20 year planned mission, and with that we’re able to observe objects for a very long time period compared to what has been available in the past. And so, yes, one of the great things that we can do is look at time variable phenomenon in the far infrared, which is something that has not really been explored very much.

Host: That is really cool about SOFIA. You guys can switch out the instruments, you can add the cryogens to keep them cool, you can go home for repairs if you need to.

Kassandra: Yeah, and we can make new instruments, design new ones based on new technologies designed specifically to observe different types of phenomena like HAWC+ and magnetic fields.

Host: Yeah, how cool. So how long are you guys going to be down in New Zealand?

Kassandra: The aircraft and observatory will be operating for about six weeks, June and July. Most of July.

Host:Yeah, quite a while. You can do a lot of science in that time, right?

Kassandra: Yeah. And one of the really cool things I think about the Titan observations is, we were talking about Cassini, the spacecraft that was at Saturn, now it’s over. You know, it had its big finale. And now we’re left with trying to observe and monitor Saturn and its moons from Earth, so the occultation method that SOFIA is very unique at being able to do, is one of the only ways to continue to monitor and learn more about these seasonal changes that Jim was talking about.

Host: Yeah, and keep going, building on Cassini data, huh?

Kassandra: Yeah.

Host: Very cool. So that’s something you’re excited for this summer?

Kassandra: Yeah. It will be very exciting.

Host: Good. Well, come back and tell us what you find.

Kassandra: Yeah, we’d love to.

Jim De Buizer: Sure.

Host:Thanks, guys.

Kassandra: Yeah.

Host: Thanks for joining us.

Kassandra: Thanks, Jim.

Jim De Buizer: Thank you.

Host: You’ve been listening to the NASA in Silicon Valley Podcast. If you have any questions, on Twitter, we’re @NASAAmes and we’re using #NASASiliconValley. Remember we are a NASA podcast, but we aren’t the only NASA podcast, so don’t forget to check out our friends at “Houston We Have a Podcast,” and there’s also “Gravity Assist” and “This Week at NASA.” If you’re a music fan, don’t forget to check out “Third Rock Radio.” The best way to capture all of the content is to subscribe to our omnibus RSS feed called “NASACasts” or visit the NASA app on iOS, Android or anywhere you find your apps.

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