Planetary Radio: Space Exploration, Astronomy and Science - Celebrating Astronomy Day with the Giant Magellan Telescope

Episode Date: October 10, 2018

Happy Astronomy Day, October 13, 2018!  We salute humankind’s long history of stargazing by checking in on what will be our planet’s largest telescope. Patrick McCarthy is an astronomer and a leader of the Giant Magellan Telescope project. He returns with a report on the instrument’s status, followed by a fascinating tour of the GMT facility. The MASCOT spacecraft has successfully completed its brief mission at asteroid Ryugu. Emily Lakdawalla provides an overview. And the space trivia contest has returned to What’s Up. See pics of our GMT visit and learn much more at: http://www.planetary.org/multimedia/planetary-radio/show/2018/1010-2018-patrick-mccarthy-gmt.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Going big for Astronomy Day, 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. Happy Astronomy Day, everyone. We'll celebrate humankind's 10,000 years of watching the skies with an update on what will be the biggest telescope ever built by far. Join me for a conversation with Patrick McCarthy of the Giant Magellan Telescope Organization and a tour of its headquarters. We'll also check in with Bruce

Betts. The chief scientist is in Washington, D.C. this week for a conference about the stuff that solar sails are made of. Emily Lakdawalla is the Planetary Society's senior editor and planetary evangelist. Emily, welcome back from New Zealand. I hope you are dealing well with the remnants of that massive dose of jet lag. Tell us about this latest touchdown on the asteroid called Ryugu. Yes, we had the success of the German-built mascot lander last week. It was really cool. It's such a tiny little robot. It's 30 centimeters square by 10 centimeters tall.

They call these hoppers or even rovers sometimes, but they're really just bricks that have little flywheels inside that allow it to reorient itself on the surface. The lander took 30 minutes to descend. It landed on the surface. They had a little bit of trouble initially getting its instruments in the right orientation because the asteroid is so dark that mascot sensors were having trouble figuring out the difference between the asteroid surface and space and figure out which direction was up. But with a little help from Earth, they finally got that figured out, and they managed three hops before the battery ran out after 17 hours of operation. Yeah, no solar panels on this little guy. That darkness is a very interesting issue because you would not know it from the images that have been returned so far.

Images, some of which contain these, well, they're calling them white spots, but are they really? No, they're not. And that's something I need to keep reminding people. The photos that we take of these objects in space, you expose the photos for as long as they need to be exposed for you to get a clear picture. they need to be exposed for you to get a clear picture. And so that means that surfaces that would be very dark, if you viewed them next to a white surface, you can actually see lots and lots of detail just because there aren't any white surfaces in the picture. But if you put asteroid Ryugu next to a bright object, like say Enceladus or Europa, it would just be this, it would be a black hole, you really wouldn't be able to see anything at all. And so in the pictures that we do have where you can see details and often these what

look like white specks, they're just the brightest bits of the asteroid. They could be quite a bit lighter than the rest of the black asteroid, but they're still, they may only have reflectances around eight or 9% as opposed to the 100% reflectance surface of, say, Enceladus. Listeners can take a look at some of these images from both Mascot and Hayabusa 2. Taken as Mascot descended to the surface, there was something so awe-inspiring about one spacecraft taking pictures of another doing something groundbreaking, literally groundbreaking, I guess. They are in your blog entry for October 5th. And I'm also going to remind folks that back in July, we talked to Hans-Jörg Dietes of the DLR, the German Aerospace Agency, about this little spacecraft. So are we still waiting for more data to come back from

MASCA? Yes, the data link between Hayabusa 2 and Earth right now is pretty slow because the distance between the spacecraft and Earth is pretty high. And so there's still data aboard the spacecraft, at least there was at the end of last week, that's going to take a while to relay. And then it'll take a while for the scientists aboard the mascot mission to actually understand everything that they've seen. So stay tuned for news to be trickling out of this mission over the next year or more to come. Thank you, Emily, and welcome back once again. That's Emily Lakdawalla, Senior Editor for the Planetary Society, with her head in and above the clouds at all times to our benefit.

If all goes well, we are less than six years away from the dawn of a new age of ground-based astronomy. Construction of the Giant Magellan Telescope has already begun on a mountaintop above Chile's Atacama Desert. In honor of Astronomy Day on October 13th, I sat down once again with Patrick McCarthy, Vice President for Operations and External Relations at the Giant Magellan Telescope Organization headquarters

in Pasadena, California. Stick around after this week's What's Up segment for a tour and a fascinating behind-the-scenes look at how it is being designed and built. Patrick, I want to welcome you back to Planetary Radio, but really I should be thanking you for hosting us again at the new headquarters of the GMTO, the Giant Magellan Telescope Organization. Well, technically, we're just a GMTO corporation. So for now, we're using organization, but we're looking forward to the time when it's the Giant Magellan Telescope Observatory.

I love that. I have to admit, it's not quite the Carnegie Institute's historical significance, but it sure looks like it's a more efficient, more productive space for you folks. Yes, it's much more appropriate as an engineering building, but there is a lot of history here. This was a NASA operations center in the 70s and 80s where they did some of their Mars operations. So when we moved in here, there's all kinds of photos of people at those old consoles with headsets and dials and

wheels and looking very NASA-like. So there's good bones and good history in this building. Yeah, that's quite a legacy. I'm glad to hear that. You have 12 partners now behind this project. Very impressive. Yeah, we're very happy to have Arizona State as our new partner. It's nice to have the whole state of Arizona on board. But Arizona State's a real up-and-coming powerhouse, particularly in planetary science. It's the new Center for Space and Science Exploration. They're doing this asteroid return mission. A lot of fascinating stuff going on there. Plus, one of my old friends, Professor Roger Windhorst, is a well-known cosmologist

and member of the James Webb Space Telescope Definition Team. So it's a great connection across all the science that we want to do with GMT. It's a great match with Arizona State. Have you run into our president, president of the Planetary Society, Jim Bell? Yes, I have. In fact, he helped us with the review some years ago. So we certainly know Jim and are delighted to have him here in Pasadena. He's a great guy.

You said all of Arizona because you've got the University of Arizona as well, right? That's correct. Still cranking out those mirrors. Absolutely. And cranking is the right word because it's really going fast now. Sometimes you spend a lot of time thinking and preparing and testing and learning, and then it all clicks. And we're happy to say that on mirror number two, they're going much faster than they expected. It's really going outstandingly well. So I think they've really made a breakthrough in the polishing of these off-axis mirrors using state-of-the-art computer-controlled polishing, and they can really converge much faster now.

So we're excited. In fact, we're the only work going on in the mirror lab now. They're working on mirrors number two, three, four, and five. And we had to move mirror one out of the lab just to make space. And as soon as two is done early next year, it's going out of the lab as well to make space for more work. So we're working 24-7 there at the mirror lab, and they're just hitting it out of the park.

So these are all in the polishing process. What's happening? Are you still spinning glass to give them their basic shape? Right. Well, we did the last spin in November of 2017 for mirror number five. And the problem right now is if we made another mirror, we don't have room to even take it off the floor. So we've really got to work through other parts of the production line. It's like an assembly line, and you can't keep putting things on the input side until you have them rolling off the finishing line. And we're getting close now to rolling

off mirror number two, and then we can think about the others. The good news is we have all the glass for mirror number six in a warehouse in Tucson, and all the glass for mirror number seven. So we've got everything we need to keep finishing all the mirrors. I'm kind of charmed by this thought of an assembly line for some of the biggest mirrors, big pieces of glass ever made, maybe that will ever be made. I think in our lifetime, they may be the biggest pieces of optical glass ever made. But you hit on an interesting point. When you think assembly line, you don't necessarily think precision, but that's what these are. These are large, but still very precise optics. And as I like to say, as you get closer to the end, you spend much less time polishing and much more time thinking.

And thinking and an assembly line don't go together. But in fact, it's still the same linear process where you work on multiple mirrors at a time. It's just at the end, it becomes a little bit of art and not entirely science. For anybody in the audience who may not have heard our previous conversations, or maybe the GMT is new to them, you mentioned that these mirrors, except for one of them, they're off-center. What did you mean by that, and why is that so key to the design of this telescope? Right. The idea is we'd love to just make one giant mirror 25 meters in diameter,

but we don't think we can make that. And even if we could, how would you ever get it to the mountaintop? It would probably fracture under its own weight. If you tried to lift it, it'd be very difficult to transport. So what we do is we take this parent surface, it's a 25 meter diameter parabola roughly, and kind of cut it out like with biscuit cutters around the edge to make it out of seven smaller mirrors. As a result is all the mirrors except the one in the middle are off on the curved sides of the bowl. And so they have their center of symmetry, their axis, not only off center from that piece of glass, but actually outside the piece of glass itself.

So they have this funny off axis shape. It's kind of like the shape of a potato chip, that it's got a saddle-like structure. And the challenge then is how do you polish this off-axis structure to the precision you need for an optical instrument, when normally we polish optics by rotating them and using their natural symmetry. So we had to unlearn a lot of things and learn a lot of new things. But as I say, we think we have a handle on that now, and we're on our second mirror that's just a very short period of time away from meeting all of its specs. How long does it take from the time you pour the glass in that spinning oven to the time you have a finished mirror? Actually, I guess because you're now getting better at it,

how long do you think it will take from start to finish for the mirrors to come? Right. It takes about four to five years, but you made a very interesting statement that kind of reflects a bit of the history. We don't actually pour the glass into the mold, which is how it used to be done, right? For the Palomar mirror, they would melt the glass in a big furnace, ladle it out, and they had these people in these, you know, flash suits and flame protectors pushing this ladle of molten glass over to pour it in the mold and then go get another one. It turns out that had its limitations, and you couldn't make an eight-meter mirror that way. So we put the glass in the mold while it's still room temperature and melt it in place. Key breakthrough. I misstated because there is a great image on the website, which we will link to from this week's show page at planetary.org

slash radio, which has like three guys on a platform and they're looking down at all these beautiful chunks of optical glass. Yes. It's 20 tons of glass handmade in Japan in small batches in these clay pots and then broken up, inspected, and then loaded in roughly five pound pieces into the mold. And that takes a couple of days. So to go back to your bigger question, how long does it take? It takes about four or five years because the first step of building the mold takes a better part of a year. Melting the glass doesn't take long, but it needs about five months to anneal. It has to cool slowly so you don't build strains into the glass. Then there's a fair amount of handling and cleaning and inspection, preparing the back surface, which has to be very

smooth to relieve stresses, attaching a bunch of hardware. That takes another year. And then when you're ready to start working on the mirror side, the front, the part that really matters, that takes about two years. There's about six or eight months of grinding the rough shape, some measuring, and then the actual polishing and figuring. And that polishing and figuring takes about 18 months. And mostly because as you get closer and closer, you spend time thinking more about where to rub on the glass. Because the founder of the Mirror Lab likes to say, Professor Roger Aindle, it's easy to take glass off. We don't know how to put it back on.

So you go slow. That's like Michelangelo sculpting a piece of marble. Exactly. I have one of my favorite T-shirts at home I got at the Palomar Observatory, and it has on the back that beautiful pattern of the 200-inch mirror for the Hale telescope. If I look at the back of one of your mirrors, is it going to look anything like that? It's like that taken

to an extreme. So the Palomar mirror that's lightweighted was a breakthrough. If you go up to Mount Wilson and you look at the 100-inch mirror, it's one solid piece of glass. It looks like, you know, Coke bottle glass. It's full of bubbles and structure, and it's extremely massive. The Palomar guys made the breakthrough of thinking, if we pour the glass into a mold that has structure that looks kind of like a waffle iron, you'll create voids and empty spaces in the back that will lightweight the mirror, but yet still make it mechanically rigid and stiff. So what the Arizona mirrors are is taking that same concept to an extreme

of lightweighting the mirrors to about 85% empty space. So there's a top surface that's about two inches thick and a back plate that's about two inches thick and then ribs that are about three quarters of an inch thick and the rest of it is empty space. So it's structured kind of like a honeycomb. It's very stiff but very lightweight. Sticking with telescopes like the Hale telescope, the 200 inch, that was, you know, the biggest on the planet for so many years. It occurs to me, as we're talking, that you have more in common, or the GMT has more in common, with that kind of classical observatory than many of the other newer telescopes, like the Keck, who use many, many, many mirrors, and they're thin, right? They're deformable. That's right. I think it was the Arizona team that realized in making

the multiple mirror telescope that also use these very lightweight mirrors that there's great advantage to the basic Hale concept of using the borosilicate glass that you can then mold into complex shapes. It has the challenge that it has non-zero thermal expansion, so you have to control the temperature. But by lightweighting it, you also reduce the thermal mass, and you can control its temperature very accurately. And one of the key reasons you want to control the temperature is not just the shape of the mirror,

but you want the air in the mirror to have exactly the same temperature because there's always air sitting right above that mirror. And if it's too hot, or the mirror is too hot, you'll get what we call seeing. You'll get image distortions right in front of the mirror. And that's something we really want to avoid. The other technology, both for the Keck telescope and the Gemini telescopes, they use glass ceramic composites to make a material that has essentially zero thermal expansion, but it can't be molded into complex shapes. So they're solid slabs. And since you don't want to make a very, very thick mirror that way, they make the slabs relatively thin, which means they're

floppy and they need a lot of active control to maintain their shape. And that's okay. Active optics was the big breakthrough that made the eight meter telescope successful. And we need active control in our mirrors as well. But the Arizona team thought that if we make them as stiff as we can and as lightweight as we can, we're way ahead of that problem. And I think that's turned out very well. And the Magellan telescopes and the Large Binocular Telescope make spectacularly good images because the optics are good and we know how to control them. And there are more terrific images on your website of laser beams coming out of this artist concept. So clearly there's active adaptive optics underway here. How do you do that if you've got, if you're working with rigid mirrors? Ah, well, yes. What you'd love to have is a telescope with an adaptive primary mirror, but no one's figured out how to do that yet.

So you have to put an adaptive or deformable mirror somewhere in your system, and there's a couple of different approaches. One approach is to reimage the overall telescope beam onto a small mirror that's deformable, and people are now using mirrors that are based on the same technology in liquid crystal displays, these micro-mirror arrays that are very small, lithographically made, solid-state devices. That has some advantages. It has some drawbacks. In the case of the GMT, we want to follow the path blazed by the multiple-mirror telescope,

the LBT, and now Magellan, is to use the secondary mirror. The second reflection in the system is the deformable element. And those mirrors are only one meter across. is to use the secondary mirror. The second reflection in the system is the deformable element. And those mirrors are only one meter across. So what we'll do is we'll make mirrors that are one meter in diameter but only about two millimeters thin, and we'll push and pull on them with voice coil actuators, just like the actuators in your headphones. It will deform the mirror 500 to 1,000 times a second

at a level that will cancel the distortions in the Earth's atmosphere. I think of it as the optical analog to your noise-canceling headphones. Because your noise-canceling headphones, they sense the thing you don't want, which is the noise. They put that same wavefront into the diaphragm, but exactly out of phase, and they cancel. So we'll use the lasers to measure the distorted optical path through the atmosphere, put that same wavefront distortion into our adaptive mirror, but exactly out of phase, and it will cancel and produce an image with the same sharpness as if you were above the atmosphere. But the challenge compared to, say,

your noise-canceling headphones is we have to do this to the precision of light rather than sound, much, much harder, and we have to change that shape every 500 to 1,000 times a second. So that's where it gets challenging. And the laser beams, we have those so they provide us enough signal so we can sense the atmosphere on those very short timescales. And these lasers, I'm going to get this wrong, I'm sure, but they are at a wavelength that they actually make that, what, artificial star at one layer in the atmosphere,

and you can use that to create the deformations that you need? Yes. There's two approaches to the laser guide stars. The one uses what we call Rayleigh scattering, which is ordinary scattering that you see in a flashlight beam or a laser pointer you go out at night, just from aerosols in the atmosphere. And the problem is that samples many different heights. The new technology is called sodium laser guide stars. So you have, as you say, light that's tuned to a resonant transition in sodium atoms. And up about 90 miles up in the atmosphere, there's a thin layer of ionized sodium that, believe it or not, comes from meteors that impact the earth and they explode and vaporize. And for a while, the sodium is floating up there. The laser beam hits those sodium atoms,

they get excited and they reflect that light back down to us. And they make this little beam of sodium light, kind of a yellowish light that we use as our guide star. What a nice gift from rocks from space. It is. And fortunately, every year that gift comes again. Not at Christmas, but in August when the Perseid meteors come, they replenish this sodium layer. And so you have to worry about where you are in the cycle. By around June and July, the signal's getting a little weaker. By August when the Perseids come, you've kind of replenished that layer again. I'll be thinking of you next time I'm out watching the Perseids in the desert somewhere around here. You know, I've had enough invitations from you and your folks.

I still hope to make it out there to the lab in Tucson to see that big oven sometime. Yeah. Well, we'll let you know when the next casting comes or when we move the next mirror out of the lab. That's also something interesting to see, how they handle that delicate but very massive and large piece of glass. So we do that process very carefully. Take us down to Chile, to the Atacama Desert. Talk about what's going on there. You're moving Earth.

Yes, we are finally making some real progress on building the observatory as just preparing the infrastructure. So in 2012, after many years of testing and building on decades of experience at Las Campanas, we leveled the top of the mountain to produce the platform for the observatory. We spent some time doing geotechnical testing where you drill deep core samples, you send those out for analysis to make sure the rock is solid, that we understand its properties. We did a little more testing of the atmosphere. But earlier this year, about July, we started the excavation, both for the telescope itself, for the telescope pier, the concrete pier that it will sit on,

and the foundations for the enclosure that will protect the telescope during the day. And this is some pretty difficult work because by taking off the top nine meters of the mountain, there's nothing there but solid rock. And so you've got to break that rock up and dig, in essence, a pit that's about three meters deep with very clean walls. And then we need to dig an annulus for the enclosure that's about two to three meters deep and several meters wide. So they're making great progress up there. And from my point of view, one of the really nice things is they're not using any explosives, no dynamite, nothing that could put fractures into the rock that could basically weaken the overall structural integrity of the underlying mountain. They're doing it all with hammers, pneumatic drills, in a somewhat slow fashion but very delicate and careful.

But they'll be done by about the end of this year. And they only started in July. So it's really going along at a great pace. You've been down there, haven't you? Yes. I've been there too. I was almost twice as high at the ALMA radio telescope array. And you're going to be at, what is it, about 8,500 feet or 2,600 meters?

Yeah. Which is pretty high. Pretty high. But the ALMA side is spectacular, but I like having oxygen. Oxygen is good because I don't think as well as I used to, and when I don't have oxygen, I really don't think very well at all. So when you go to the very high sites, you have to be prepared for your own personal safety, for the safety of the people you're working with,

and you have to take precautions to make sure that the decision-making is really properly done. And for ALMA, they do all the decision-making, the hard work at the lower elevations. Yes. So for optical astronomy, though, 8,000 feet is a good place to be. We're above much of the atmosphere, but not all of it. We can still work very effectively. We think it's a great site. I've been going there for 30 years.

I just love being there. My only complaint is it's a long trip. I've been going there for 30 years. I just love being there. My only complaint is it's a long trip. Yeah, but a beautiful, beautiful place. Wonderful. They did give us little cans of oxygen that we had to take a hit off of every couple of minutes. Otherwise, you were getting pretty slap happy and maybe worse. Was that the key part of the decision in picking the Las Campanas site that you did? No, the main consideration was

that we had about 40 years of experience because the challenge in picking a good astronomical site, well, you know a few things. You want it to be dark, so you want it to be free of light pollution, but really you want good weather, stable weather, good airflow. And if you take a, you know, if you survey, say, a half a dozen sites for three years, you'll pick the one site that had three really good years of weather. And so people have learned that by making site selections on the basis of just a few years of data, you tend to pick the statistical outliers. So at Las Campanas, having 40 years of experience, we knew the weather patterns were stable. We knew the light pollution was not going to become a problem.

We knew the seeing was outstanding, and we had multiple years of data. And that gave us the confidence if we're going to build something to last for 50 years, we want to put it in the right place. And there's nothing like having 40 years of experience to make that decision. Before we started recording, we were talking about seismic issues. And without going into detail, you have good reason to know how serious those can be. This is not the most seismically stable spot, but you're satisfied with it. Yeah, but to step back and take a bigger perspective, we like to put observatories on tall mountains. Tall mountains are typically young mountains. And I like to remind people that mountains come from volcanoes and from plate

tectonics, and you kind of have two choices. You can have earthquakes or volcanoes, or you could have both if you really like them both. The place we are in Chile doesn't have any volcanoes, but it is seismically very active as the two plates collide that created the Andes. We know that we will encounter a magnitude 8 earthquake at some point during the lifetime of the observatory, just from the historical records there. So we have to build the observatory. So first of all, that in any seismic event, we will not injure any of our personnel or visitors. But we also want to make sure we don't damage the telescope,

and most importantly, that we don't damage the delicate optics. So we've done a great deal of design work to understand the implications. We've put seismic isolators into the telescope itself, and so we feel now that we are ready to deal with pretty much whatever comes in the point of seismic events. And we are targeting a nominal return period, as they call it in the seismic world, of 1,500 years. And I think that's a pretty good period of time to base the baseline. Not bad. Yeah. How far off are we from first light, from seeing this beautiful structure

with laser beams shooting out of it. Well, you know, the project manager keeps a schedule. There's always risks associated with that. But right now, we expect that we'll have the telescope inside the dome and some of the mirrors sitting in a warehouse next to the telescope in 2024. We probably won't have all seven, but I'm pretty confident that once we have a telescope and we have some mirrors, we'll put some of those mirrors in the telescope, see how it works.

We'll have the world's largest telescope at that time. I'm sure the astronomers, like myself, will want to do some science. So we're hoping that we'll do engineering and then scientific first light in that 2024, maybe 2025 timeframe. 2020 is something that always sounded like a long way away to me, but it's not so long any now. This is late 2018, so 2024 doesn't seem that far away, really. So clearly, you don't need the whole set of mirrors to start doing science. That's right. We think if we put four mirrors in, it'll be the largest telescope in the world by a long shot. We'll be able to exercise the control system, align the mirrors, do all the basic

functions. You won't have all the capability. First of all, you won't have all the sensitivity, but when it comes time to doing adaptive optics, you really like to have that full mirror array because the primary mirrors kind of key off each other and they tune up together. So that really will work better, but we could do even that with a subset of the mirrors. So that really will work better. But we could do even that with a subset of the mirrors. Speaking of science, even this far out from this telescope, starting to gather enormous amounts of light, are there preparations underway for how that science will be conducted and managed?

There is. There's a bit of thinking going into the vexing question of how you decide whose project gets on the telescope, which is always complex. But ultimately, it comes down to a peer review process. And we always want to say that anyone who's got a good idea can take her or his proposal to the review process and see that it gets a fair hearing and that the best ideas always get on the telescope. But now we're going through a process in the U.S. called the Decadal Survey of Astronomy and Astrophysics, which we do every 10 years. That's the name, Decadal Survey.

And one of the things we're thinking about is enlisting the full community of U.S. astronomers to come forward with their best ideas for big projects. What are the really big things you'd want to do that you couldn't do, say, in an hour or a night necessarily, but you might need 10 nights or 50 nights to address the big questions like, is there life on other planets? What is the nature of dark matter? How did the first elements form? When did first light occur?

And so that process is now being organized. There's about 250 or more astronomers around the U.S. collecting together ideas and crafting some of these big visions that we might use the GMT to address. And that process will sort of play out over the next 18 months or so. What are the challenges, the scientific mysteries, that not just the GMT but this whole new class of terrestrial telescopes are hoping to find answers for? And I'll give you one up front because, of course, we're the Planetary Society, and that's finding those other worlds and maybe those signs of life that you just mentioned.

Yeah. Surprisingly enough, the big questions have been around forever. Where are we? Where did we come from? Where are we going? And perhaps most importantly, are we? Where did we come from? Where are we going? And perhaps most importantly, are we going there alone? And in my lifetime, my career, I've seen this incredible explosion and development of exoplanets, science planets beyond the solar system, and it changes on such an amazing timescale. But there are reasons now to believe that this whole question of are we alone is now a scientific question,

not a philosophical question or a science fiction question. And we know there's this extraordinary effort to search for intelligent life through communications, through SETI and so on. But there's a more basic approach to ask, can we find the chemical signatures of life? So I like to think that there's people out there who are listening for life. We want to go out and smell, which might seem odd, but what we want to do is ask, is if you came in and looked at the Earth's atmosphere and knew nothing else about the Earth, could you detect that there was life here just from the atmosphere chemistry? And the answer is very clearly yes, because 20% of the Earth's atmosphere is oxygen. And if there wasn't something replenishing in that all the time, namely photosynthesis,

everything on the surface of the Earth would rust and all the oxygen would go away in just a period of a few thousand years. So there are planets now that we know of that are like the Earth or a little larger, that are in that zone, the Goldilocks zone, where it's not too hot so that all the water vaporizes or too cold so that everything turns to ice. But in this just right zone, biology might occur. And as those planets pass in front of their parent star, some of the light is blocked by the rocks and so on in the planet. But if there's an atmosphere, the light goes through that atmosphere and some of it is absorbed by

molecules. Those molecules could be carbon dioxide or carbon monoxide or ozone, also diatomic oxygen. What we want to use the GMT for is to look for those signatures because right now it's simply too hard to do with the telescopes we have. They just don't have the sensitivity. But the next generation big telescopes should be able to do that. And the Webb Space Telescope has a key role to play in this in that it will find which planets have water in their atmosphere. Because we can do that from the ground,

but it's really hard to distinguish the water in our own atmosphere from the water in other planets because the water in our atmosphere makes it opaque at many wavelengths. So it makes it a little challenging. The Webb will be great at that. Because it's an infrared telescope. Because it's infrared and it's above the atmosphere. So it doesn't look through any water. But it won't have the finesse needed to do the oxygen problem.

So we think that's really the domain of the extremely large telescopes. And that's part of why we want to be on the sky first. And part of why we're building our first instrument to exactly address that question. Can we find the oxygen? But it's not alone. You mentioned dark matter, dark energy. I'm thinking University of Texas, Austin, one of your partners, McDonald Observatory. I've been there, and that's something they are hot on the trail of. Absolutely. They have a great experiment there to measure the sound waves,

in essence, in the early universe. So we have this kind of embarrassing problem in astronomy in that we don't know what most of the world and the universe is made of. You know, 96% of the stuff, we don't really know what it is. We know that there's the dark matter that responds to gravity and drives the structure formation in the universe. It drives this formation of galaxy clusters and galaxies and large-scale structures that we see. But we don't really know what it is from a fundamental physics point of view. We know a lot about what it's not. And then there's this dark energy that permeates everywhere and is driving the acceleration of the universe, the acceleration

of the expansion, and we know very little about that. So the GMT, the James Webb Space Telescope, experiments to look at the cosmic microwave background, many of them will address these physics questions through astrophysics by trying to understand the nature of these fundamental physics through their impact or their imprint on the universe. And these are big questions. Not only where do we come from and where we're going, but what the heck is all this stuff?

And how do we, this 4%, fit into all of that? What else? What have we missed among these great questions? Oh, well, we've missed an enormous amount. We've learned just recently that there are giant sort of 20, 50, 60 solar mass black holes crashing into each other, making gravitational waves. That's a bit of a mystery of how those objects formed and got close enough and didn't blow themselves apart in the process. We now know that there are emerging neutron stars that make gold and platinum and many elements, but we don't know how often and where, what kind of environment. So there's a whole new world of what we call multi-messenger astronomy. Yes, I was glad you mentioned it.

So there's an old, becoming an old astronomer, we think of astronomy as electromagnetic radiation that comes from the stars and from gas. But now we can see this gravitational signatures, which at their peak are the most luminous, the most energetic phenomena in the universe. And we're starting to now combine particle physics in astronomy and that we can identify astrophysical sources of neutrinos and cosmic rays. And this question of where the cosmic rays come from is a fascinating one. I think astronomers are now finally starting to crack that, and it's really quite an astonishing result. You paint a thrilling picture of the future. Even with 12 partners, this is an expensive

proposition, even spread among those 12 partners. Are the resources in place now to get this Are the resources in place now to get this working? Well, these projects have many challenges. There's technical challenges. There's social challenges. There's coordination and organization. And, of course, there's a financial part that goes with it. And we haven't solved all of those financial problems just like we haven't solved all the engineering problems.

We're confident that we have a path. We have a lot of resources in hand. That's what's led us to make all these mirrors and level the site and do the excavation. And we're about to sign a contract to build the telescope steel structure here. But we haven't gotten quite to the finish line yet. But we feel that we're making progress. We're building excitement. And that in some sense, the best way to generate success is to accomplish success. And if we all waited until we had every last dollar and everything worked out before you started, we'd have never started. So we have some work to do there. We're always looking for additional partners.

We're looking for people who are excited about science, cosmology, life elsewhere in the universe who want to be part of the team. So we're looking for those who want to help us succeed. Very much in the tradition of that great astronomer, George Ellery Hale, who spent so much of his time trying to find the resources he'd need to build the next great telescope. Yeah, if he'd only left us an instruction set, if he'd only said, here's how you do it, here's my secret, that would have been really helpful because, boy, was he good at it. He really was extraordinary. I said you represent a whole new class of telescopes, and there are at least a couple of great examples that are going to be the sisters of the GMT, and they're making some progress. But I just wonder if you have any thoughts about the troubles that particularly the TMT, the 30-meter telescope, has gone through

and how you feel about the fact that that instrument has effectively been blocked, at least so far. We all hope that there will be some kind of solution found. Yeah, well, we certainly hope that they, and are confident they will achieve ultimate success. We think it's very important to have an extremely large telescope in the Northern Hemisphere. There are unique objects in the sky that can only be seen from the Northern sites. And we love the idea of having a telescope in the North and in the South that has U.S. involvement so people can do their science anywhere in the sky or use all-sky science. As I said, when you build these big projects, there's a whole host of challenges. There's the technical challenges, which turns out are really not the hardest.

There's social issues that you have to work through. There's financial and business issues. They seem to have taken a careful and deliberate approach to this. We think the best thing we can do to help them is to stay out of it and just emphasize how important it is for astronomy that they ultimately succeed. And we wish them the very best and look forward to working with them. You and I have been talking about this for some years now. How long have you been part of this project? Oh, I think we must be on about 15 years or so. But I think one of the things you learn

from big science projects, and you can look back at the Hubble Space Telescope, even the Webb, is the time from when the idea first starts to grow, and it started to grow amongst those people who had built the 8-meter telescopes, to when you're ready to start building and cutting metal is very long. And when you're going to do something that's billion-dollar scale and should last for decades, you probably want to spend a lot of time thinking about it. But you have to be an optimist when you start. If you didn't have some belief you could get there soon and faster than you really can, most people probably would never start. So it's a natural phenomenon at the beginning. You're very enthusiastic.

You tend to underestimate some of the challenges. And then you bring in a professional team that manages it and gets you where you're on the right path. And we now have that team and that structure. And that's why we're in this beautiful building, to have room for 100 or plus people to do all that work, to make it the actual vision that was started in Carnegie and Tucson and various places 15 years ago, now taking shape in Chile and in factories around the world. So similar, so many parallels to the stories that I've heard from many, many principal investigators for planetary science missions, rovers and trips to Pluto. There's a quote from you on the GMT website that I really love. Do you know it offhand or should I read it to you?

You better read it. Okay. It won't be a surprise, I think. The essence of our species is to explore, to find new answers and new meaning for who we are. Is that what drives you? Yes, I think so. It's a desire to be part of something bigger than you can do as an individual and to just, the way I like it is, you spend your life hanging around here, you ought to know where in the heck you are. Everybody, you know, it goes back to the early explorers.

They wanted to know what are the boundaries of the world? What is out there? Where do we live? And how does it all work? And I think that's a life well spent if you can make some contribution to that. Great talking to you again. I look forward to yet another update, making it to that

lab. And someday I'd love to climb that mountain. Come down to Chile with us. Love to have you. Patrick McCarthy of the Giant Magellan Telescope. Stay with us for that tour of the GMT offices and some very cool demonstrations. That's coming right after we visit with Bruce. Time for What's Up on Planetary Radio. Bruce Betts is the chief scientist of the Planetary Society. We find him this time in his Washington, D.C. hotel room, and you are there for what? I am here for one of the most complicated named workshops I've ever attended, the metamaterial films for in-space propulsion by radiation pressure incubator. That really is. So the stuff you might make light sails out of.

Exactly. So coming from the solar sail side and it's bringing together solar sail people, and it's actually hosted by the Optical Society. So it brings together experts in exotic optical materials that you could make a whole different kind of solar sail out of, so-called metamaterials with weird properties. Sounds like fun. I'm glad you could take time to talk to us in what's getting to be pretty late evening there. And tell us what's up in the night sky. By the way, we're hearing proof of the usual thing you get from hotels' so-called high-speed Internet, so the audio may not be the greatest. But it's good enough to tell us what's up in the night sky. Jupiter low in the west in the early evening, and then Saturn in the southwest.

Mars still looking bright but dimming pretty fast but still brighter than most stars looking reddish in the south and the moon will be hanging out next to Mars on the 17th and 18th so that'll make a lovely little combination. We move on to this week in space history. It's the 50th anniversary, the first of several we will have for Apollo human spaceflight missions. It's the 50th anniversary of the Apollo 7 mission, Earth Orbiter. We're going to have some spiffy coverage of those Apollo anniversaries, including I think we're going to have some pretty pictures from Apollo 7, some groovy pictures. All right, we move to random space fact. A long-distance random space fact.

Apollo 7, I may have mentioned that. It was the first Apollo mission to carry humans into space, the first three-person American space mission, and the first to include a live TV broadcast from an American spacecraft. So I lost count. What is that, four firsts? There were more. There were three or four, and there were ones involving food and I don't know. We'll come back to that later. All right, let's go on to the trivia contest. Are we answering something this week, Matt? Indeed we are. It's next week that we will not be answering anything, but I think you've got

something for us this time about a rocket. Yeah, I asked you how many total launches were there of Delta II rockets. How'd we do? This is so interesting. We got a typical, very nice response, How did we do? This is so interesting. We got a typical, very nice response. And most people said 156 launches. That included this week's winner, David Hoven of Boynton Beach, Florida. Boynton Beach is just a little bit too far south, I think, for him to have enjoyed any of those launches unless he drove north 100 miles or so. David indeed said 156 with only one failure

and one partial failure. Now, we did have some people who said it was really 155, but I think this is the difference between ULA counting what they called missions, which were successful, and launches, which included that one complete failure. I don't know. Does that sound reasonable? Sounds reasonable. And as we discussed together, we would have accepted either. Very good then. David, congratulations. You are going to get a Planetary Radio t-shirt from the Planetary Society Chop Shop store. That's at chopshopstore.com. Planetary Society Chop Shop Store, that's at chopshopstore.com, and a 200-point itelescope.net astronomy account from that worldwide network of terrific telescopes, operated on a non-profit basis, 200 points worth a couple hundred bucks. Here are some of the other responses we got from

Mark Little in Londonderry, Northern Ireland. The first Delta II was launched on Valentine's Day, 1989. Coincidentally, the song Straight Up by Paula Abdul was number one on the U.S. charts. And Mark was hoping that you would sing a few verses to us, but maybe next time. Okay. Laura Dodd in Eureka, California. She says that one failure, which was in 1997, didn't harm any people, though several cars were destroyed. She adds that must have made for some interesting insurance claims. Tony Knutson in Stewartville, Minnesota, accounting for inflation if you spread the cost of all those launches over the entire U.S. population, comes to about $53, just slightly more than a membership to the Planetary Society.

I don't know, should I have included that? Yeah, I think that's about right for a basic membership. Dave Fairchild, our poet laureate, the Delta II rocket was launched into space for 155 shots with only two misses. I'd say that the rate is about at the highest of spots. For 29 years, it would soar through the sky till it ended in 2018. And just for the record, our poor Lottie Williams was hit by some Delta debris. That was the woman you mentioned last week. One more I can't resist from Craig Balog. the woman you mentioned last week. One more I can't resist from Craig Balog. He says,

two of those successful launches occurred back in 2003 to send Mars Exploration Rover Spirit and Opportunity on their way to Mars. Fingers crossed Oppy wakes up and calls home soon. I went to go see one of those launches. Had to leave Florida as usual after it was delayed and missed it. All right, I move on to the next question. It's Apollo 7 all the time. What rocket launched the Apollo 7 crew? Go to planetary.org slash radio contest. You have until the 17th. That would be October 17 at 8 a.m. Pacific time to get us your answer and win yourself maybe a Planetary Radio t-shirt, an itelescope.net astronomy account, and

as promised at the end of last week's show, a signed copy of the Penguin Book of Outer Space Exploration. NASA and the incredible story of human spaceflight. This is that latest book from John Logsdon. He edited it, wrote all these little connecting essays. It has all those original

documents that trace the history of human spaceflight, at least in the United States. Fascinating, terrific little book. All right, everybody, go out there, look up at the night sky and think about Pepper. Thank you and good night. the night sky and think about Pepper. Thank you and good night. Achoo! He's the salt to my pepper. That's Bruce Betts, the chief scientist of the Planetary Society, who joins us every week here on What's Up. Okay, let's go back to the big new headquarters for the Giant Magellan Telescope as it comes together. It's time for a brief tour of that sprawling facility. Hi, my name is David Schwartz. I work on the integrated modeling team at Giant Magellan Telescope. I've been working on this project for a couple years, and it's just been really

exciting to see it develop and to hopefully get to see it be built in the next couple years. And you know how you got stuck having a microphone stuck in your face today? It's because I saw your cool shirt while we were riding the gold line, the train that runs through Pasadena. As I was coming to my office and you were going to yours. Yeah, that's true. We were both commuters, lovers of public transit in Pasadena. You're going to show us around a little bit? Well, yeah.

First, we actually got a virtual reality version of our telescope set up in here. And we use this for outreach right now. And it actually has a really good amount of detail. And yeah, maybe you could try it on so you can see what it's going to look like when it's up on the mountain in Chile. I'd love to. You're sitting there with the headset. We'll give it a shot. And obviously, this is a completely interactive, but a real physical model that have you built in all of the dynamic characteristics of the structure and so on? We have, but not in this model. That's part of Dave's work. So we've just flown inside the telescope structure now, and I'm looking down at those beautiful big

mirrors that are actually coming together in Arizona. This is spectacular. And there's a little human in a hard hat to give us an idea of the scale. That is spectacular. I can look right up at what the telescope is looking at. It's a little bit of a cloudy day here in northern Chile. You should introduce yourself as you give me this little virtual tour. I am Patricio Schurter. I'm a mechanical engineer here. Is this a particularly exciting project to be involved with? Absolutely. I've worked in telescopes all my work life, previous generation of large telescopes,

and now being involved in the next generation of large telescopes to extremely large telescopes. It's really exciting. Go actually go in the telescope, which is what I'm doing right now. Yeah, we're diving right through the telescope itself, this massive steel and concrete structure. And so here we are now looking at, which mirror is that? That is the tertiary mirror. And if you could go in a little bit. I'm leaning down, almost hit my head on the table, and I'm looking under the mirror now. Yes. At actuators, it looks like.

Yes. If you look up, you will see the secondary mirror, right? Oh, yes. Not surprisingly, seven secondary mirrors, one for each of the primaries. Exactly. Beautiful, beautiful stuff, folks. All right. Thank you for the virtual tour.

Where are we headed now? Now we're heading to our prototyping lab where we're working on the actuators that will hold up the gigantic M1 mirrors. The primary mirrors? Yes, the primary mirrors. So they're each 17 metric tons, and they're floated on a bed of pneumatic actuators,

so it's like they're sitting on an airbed. But there's also a hexapod of stiff actuators that they use to control the position at an extremely fine level, and they're testing that right before our eyes. You know, I only expected to see a bunch of cubicles, workstations here. I did not know that there would be physical work underway. Hi, everybody. We're from the Planetary Society and Planetary Radio, and so Dave has given us a little tour.

What we have in front of us, it's an actuator. It's made of steel? Right, yeah. About five feet long, and it's relatively narrow inside a text fixture. We'll try and get a shot of it, and we'll put a photo up on this week's show page, planetary.org slash radio, so the people, if it's okay to take pictures. Oh, absolutely. Great, thank you. Some places we go, they don't like that.

Oh, it's a telescope. Yeah, what is your name? My name's Tony Hebert. What's your job here? I'm doing the hard points, basically taking it to a functional state. So we have a prototype here. We're basically going to test it against our requirements to make sure that it performs the way it needs to in order to position the mirror. And then once we test it, we're going to build six of them,

and then we're going to put them into a test cell that will integrate all the rest of the hardware and then actually put a mirror on it and then test it with a mirror on it. Six of these per mirror, per each of the primary mirrors? Exactly, six per mirror. I think we're going to have a total of 52 total hard points in the telescope, and they're all going to act together to position the mirrors. When you say you're going to put a mirror on six of these to continue the testing at some point, are you talking about one of the real mirrors? One of the real mirrors. Yeah, for fingers crossed.

No, there's going to be a lot of functional testing and proofing out of the cell with a dummy mirror. It's just a piece of steel. And once we're sure that everything is functioning properly, then we'll put the mirror on. What kind of precision do you have to achieve with an actuator like this? About plus or minus 200 nanometers. Pretty precise. Yeah, if you breathe on it, it'll move.

What a great mechanical challenge. It's exciting. Yeah, yeah. If you breathe on it, it'll move. What a great mechanical challenge. It's exciting. It's fun. We're headed toward your workstation now? We have people of so many different expertise. We have astronomers here, it's scientists, and we also have mechanical engineers

and systems engineers, and I can just walk over to any desk I want and ask for something I need at any time. It's really fun. It is really a dream job for me, I'll be honest. When I look for joy in my career, I like to have challenging problems. I really like math. I've generally been able to find that,

but I also want to work on something that I know is going to have a lasting impact. And a project like this that I know is going to be around for 50 years and assist generations of astronomers with making discoveries, it's just amazing for me. We have these beautiful windows that look out actually to Mount Wilson. It's covered by clouds today, but you can see the peak where so many amazing telescope discoveries were made about 100 years ago. And so you always feel that connection to the past when you're here.

So we're at Dave's workstation now, his portion of this big office, and that is one beautiful animation once again. I usually am very happy to be an audio-only medium, but not this time. Tell us what we're looking at here. Let's back up a little bit. One of the main challenges with designing a ground telescope is that you have to contend with the atmospheric distortion. I think most people have experienced when they look at asphalt on a hot day,

you can see the mirroring that happens. And that is just terrible for telescopes. And so you want the stablest air possible. And what we found in other telescopes, other ground telescopes, is that the enclosure that the telescope sits in is actually terrible. It heats up during the day. That heat causes these turbulences that causes the images of the star to move around, which is terrible for image quality. So what we really want to do is try to optimize the enclosure design to make that air as steady as possible.

But this is really a great example of what modeling can do for you. We reached out to Boeing and RWDI to do a computational fluid dynamics simulation, and that's what we see here. And it's what we're watching on the left-hand side. We're seeing streamlines that come in over the mountain. That's the wind coming in toward the observatory, right? Exactly. We're modeling a predominant wind out of the east, and you can see how it flows around the telescope. And you get really valuable information out of this. There's a layer of warm air around the ground, and you can see how that warm air gets kicked up into the telescope field of view.

You can see all sorts of turbulences on, we mentioned the necklace vortex, and you can see that kind of at the bottom and you have this spinning vortex that goes around the bottom of the telescope. Yeah, it's gorgeous. It's this, the lower portion of the wind hitting the observatory that really does become a vortex. And what do the different colors represent? It's the speed. And so what you're seeing is just like when you go around, when air goes around an airplane wing, it speeds up as you go around something. You're seeing that here. And so as it goes around the base of the enclosure, the air speeds up. You can see behind the telescope that the air is going a little bit slower down. Speaking of airplane wings,

You can see behind the telescope that the air is going a little bit slower down. Speaking of airplane wings, airfoils, I see a lot of curved surfaces. Is that partly what you're coming up with here, the optimum shape for not just the entire building, but these individual portions of the structure that will surround the telescope? Absolutely. We use these models to do trade studies. Is it important to make sure all these surfaces are curved? How much of an impact does it have? Because there's always this cost versus performance tradeoff, and these models help tremendously. We do use wind tunnel prototypes as well.

We'll build 3D models, and that helps test and validate this, but these computer simulations are just incredibly valuable. How much data are we talking about here? This has got to be a pretty complex and taxing model, if you're the computer that this is running on. Absolutely. A lot of these models take weeks to run. They generate terabytes of data. And so despite all the advances we've had in computers and data storage, these still push the limits. These really are gorgeous. I mean, they ought to be in a gallery someplace. But I hope that we can share at least some of these on the show page. Me too. I'm sure we'll find a way to do it. So you mentioned wind tunnels,

and that you do some physical testing of models. And how good is this science or art of modeling that we're looking at now? I mean, how important is it still to build something in the real world, even if it's a scale model, and see how it behaves and how close it comes to the model. We still rely heavily on what happens in the real world. Models are absolutely fantastic for trade studies, but if you don't take it to the real world and compare your model against it, if you don't do these wind tunnel studies, it's often hard to have a lot of confidence. And we still are always trying to tie things back into the real world. And that's one of the things when we think about the future of modeling is trying to reduce those error bars to the point where we don't have to spend as much cost on testing and prototyping.

That we can just trust our models and design from there and be confident. And that's where I see things going in the future. But it sounds like already at this level of sophistication, you're eliminating a lot of the uncertainty that you would have had, let's say, if you were designing the Palomar telescope back in the 1940s and 50s. Absolutely, yeah. It's amazing. It's so amazing what they were able to achieve

100 years ago when they're just amazing engineers that they didn't have these tools. They learned from generations before them and they built in a ton of extra margin. They made extremely robust designs because after all the effort, things had to work. But now, since we're able to do these complicated computer simulations, we can make more efficient designs. We can do just more amazing science. It's going to be, we were told, maybe, if all goes well, 2024, before even a good portion of this telescope starts to do science. You think you're still going to be here then?

And what's that going to feel like when first light is achieved? Oh, my gosh. I really hope to be around. I'll still be, whatever happens, I'm still going to be a huge fan of the Giant Intelligent Telescope program. And, yeah, it'll feel amazing just to see those first images, see all of our hard work pay off. It's just going to be amazing when you think it's going to be image quality 10 times more than Hubble

and the sensitivity to photons 100 times more. We're going to see things that we've never seen before. Exciting stuff. Thank you, Dave. I'm really glad I ran into you on that train. Yeah, me too. This is so cool that I get to share this with you and your audience. I'm really pleased. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its members who watch the skies. Mary Liz Benders, our associate producer, Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser.

I'm Matt Kaplan. Ad Astra.