Planetary Radio: Space Exploration, Astronomy and Science - Starchaser: Extraordinary Astronomer Jay Pasachoff

Episode Date: June 5, 2019

Jay Pasachoff visits Planetary Society headquarters for a conversation about the latest edition of his and Alex Filippenko’s monumental textbook The Cosmos.  But that’s just the start of a discussion that explores solar astronomy, art and science, the history of astronomy and Jay’s nearly 60-year history of total solar eclipse observations.  The Planetary Society’s LightSail 2 may look like LightSail 1, but Jason Davis tells us there are important differences between these spacecraft, beginning with their missions. What’s Up brings another opportunity to win Alan Stern’s great book, Chasing New Horizons in the space trivia contest.  You can learn more about all of this week’s topics at:  http://www.planetary.org/multimedia/planetary-radio/show/2019/0529-2019-jay-pasachoff.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Extraordinary astronomer, author, and eclipse chaser, Jay Pasikoff, 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. As you'll hear, Jay Pasikoff doesn't like the term Eclipse Chaser. His alternatives for that title are part of our wonderful conversation with him that will touch on art, poetry, mysteries of the universe, and the history of civilization. Jay also makes a cameo appearance in this week's What's Up segment with Bruce Betts. You might win a copy of Chasing New Horizons in the Space Trivia Contest. Why is the launch of a second LightSail spacecraft so important to the Planetary Society?

That's just one of the questions answered by the Society's Jason Davis in our opening segment. Jason, you already wrote last week, that was your May 30 entry in the Planetary Society blog, LightSail 2 arrives in Florida, that our spacecraft is at its final destination, at least before it takes off for Earth orbit. And it's, what, inside the Prox-1 carrier now? Yeah, it's already inside the spacecraft. It's been there since it was

integrated back in New Mexico with the Air Force Research Lab. And then they shipped them both as an integrated unit down to Florida. So presumably at some point very soon, it'll get attached to the launch vehicle. From there, it's launch time. So it's coming up fast. And as far as we know, that launch date is still set for June 22nd? Yes. And we have a time now, 1130 in the evening. So it's going to be a night launch for the Falcon Heavy.

You and I will be there watching and that really will be spectacular. Yes. Yeah. That should be something to see. You have this new piece, which is out today as this program is published on the Planetary Society website, that being June 5th. And it talks about the differences between LightSail 1 and LightSail 2, which I guess we've gotten a lot of questions about. Yeah, we wrote this just to have something to refer to because we do get this question a lot. What are the differences between the two spacecraft? You know, they're very similar. And from the outside, they look almost alike. But there are

some key differences. So that's why we wanted to publish this ahead of the launch. Now, the big difference is nothing internal to the spacecraft. It's just where it's going, which we've talked about on the show before. But just very briefly, we're going into a higher orbit this time. Why is that? Yeah. So atmospheric drag is still a pretty dominating force in low Earth orbit. The International Space Station, which is about 500 kilometers, has to raise its orbit every now and then with thrusters because it's slowly being dragged down. So we need to go to a higher orbit where the thrust from solar sailing can overcome that. And that generally, you can barely overcome it around 700 kilometers. We're going to about 720

kilometers, and that should just be enough to where we can make a measurable change in the orbit from solar sailing. We'll be able to sail on the light of the sun for the first time, at least for a Planetary Society spacecraft. I know there are software upgrades as well, based on what we learned from LightSail 1, but let's go on to a couple of hardware improvements, including the presence this time of a momentum wheel. I still like to call them reaction wheels, maybe as a tribute to Isaac Newton. Yeah, yeah, exactly. The right-hand rule where you curl your fingers in the direction something's spinning, and then you point your thumb up, and that's the direction of the force that's imparted.

At least, I think I have that right. I'm obviously not a physicist here. But I like that. Yeah, yeah. Bigger spacecraft use sets of these to do all of their attitude control, meaning to turn around in space. And they spin one of these things up and it actually rotates the spacecraft in a certain direction. Light sail doesn't need three momentum wheels because it's a smaller spacecraft. So it uses these little torque rod things to do its turning. But when it turns its solar sail back and forth, that is a pretty big force required to do that when the sail is out.

So it needs a single momentum wheel to do that. It makes two 90 degree turns each orbit using that momentum wheel. So the first spacecraft did not have one of those installed because we didn't need one, but the second one definitely does. So that's one of the big differences in hardware between the two spacecraft. So we'll be keeping that momentum wheel pretty busy, it sounds like, if it has to do this twice every, what, 90 minutes or so, I assume. Yeah, exactly. And the torque rods we talked about before, they're just so cool.

Using the Earth's magnetic field to adjust the position or at least the orientation of your spacecraft. Really, what is cooler than that? Yeah, yeah. It's like a magical free form of attitude control. It's pretty mind-blowing. And I didn't even know about these until I started learning about the LightSail mission several years ago. Actually, I just heard people that have been following Starlink spacecrafts that SpaceX launched, they use torque rods for some of their orbital changes or rather attitude control changes as well. So yeah, these are pretty common. It's a pretty neat concept.

I'll be darned. I didn't know that about LightSail until recently either. And I sure didn't know it about those new first in that constellation from SpaceX. All right, finally, we have these little reflectors on LightSail 2 that were not on LightSail 1. And they mean that we have this much in common with that Beresheet spacecraft that the folks in Israel sent to the moon. And who knows, those mirrors may still be in little pieces somewhere on the moon. Why are they there on LightSail 2? Basically, when you want to find the distance to something really precisely, you can shoot a laser at it. And when the reflection comes back, you measure how long it took for the reflection to come back. And that will give you a distance

estimate because we know the speed of light is a universal constant. Beresheet had them because we were going to use them as kind of a navigation system in orbit. They were actually retroreflectors left by the Apollo missions on the surface of the moon that we can still, to this day, shoot from Earth and tell how far the distance is between the Earth and the moon. Beresheet had one because, you know, NASA is really interested in going to the moon and they need to kind of build up a navigation system for when spacecraft are in orbit. So orbiting spacecraft can zap these things and tell how close they are to the surface, essentially. And that's what we're going to do with light sail. We're going to be able to zap it from the ground and determine exactly where it is in space. Now, that's really important for light sail because we're trying to measure the change in its orbit from solar sailing. So we need really precise orbital measurements, and that's one way we're going to do it.

LightSail 1 had a few of those small mirrors on it, but for LightSail 2, they wanted to make sure that we get that signal back and added a cluster of mirrors on the bottom of it. So that should be enough to get that return signal and tell where it is. More extreme coolness, bouncing a laser off of a solar sail. Almost a little preview of how light sails may be driven outside the solar system someday by much more powerful lasers, we should note. Jason, thank you.

I sure look forward to joining you in Florida on and even a little bit before June 22nd for that launch. Yep, sounds fun. I will see you there. That's Jason Davis, our embedded reporter with the LightSail project, also the digital editor for the Planetary Society. When I learned that Jay Pasachoff would be back in Pasadena, I hoped I'd have another opportunity to sit down with this astronomer and astrophysicist who has witnessed eclipses around the world for nearly 60 years. As you'll hear, Jay has contributed much more than good science to society. We'll talk about his first love, solar astronomy, before we move to his love of astronomy's long history and its ties to artistic endeavor.

Sharing his passion has always, always been part of his work. Jay Pascoff, welcome back to Planetary Radio. It's great to have you here in the Planetary Society studio for a conversation. Well, I'm really glad to see your new studio. And I've known a lot of people at the Planetary Society for many years, going back to when I was a Harvard undergraduate and Carl Sagan was assistant professor there. And I've met Bruce and Bill, and it's a very great pleasure to be here with you. Bruce Murray, Bill Nye, I bet you've run into Lou Friedman too. Can't miss Lou.

You mentioned to me when we saw that nice portrait of your former professor outside, and I didn't realize that he had been at Harvard before he went to Cornell. Yes, he was very inventive then. I remember being with him at some party at night, and there was some little game being played where you imagined a room, and most people said, all right, it's a six-by-nine room, and we have a library or something. But he added extra dimensions to the room when he gave his answer. So even then, he was a very inventive fellow. answer. So even then, he was a very inventive fellow. Yeah, and lucky for Cornell, they were the ones who gave him tenure, and he spent the rest of his career there. My understanding was he was a little too inventive for the Harvard Astronomy Department at that time, and they weren't sure he was going to settle down and do grinding astronomy. He was interested in too many other things, so they didn't give him tenure. Lucky for us, he never did settle down that way. Well, the last thing he said to me when I visited him at Cornell is that he said,

Jay, we ought to see each other more often. So I remember that, but unfortunately, he died too young. That's a lovely tribute, though. You and another one of my contemporary science astronomy heroes, Alex Filipenko, are about to publish the fifth edition of the Cosmos Astronomy in the New Millennium. I'm reaching over for the paperback copy that you brought in, and even the paperback is so heavy, I have to strain a little bit. It's already being called the best written introductory astronomy textbook on the market, but then you've been out there for a long time. astronomy textbook on the market, but then you've been out there for a long time.

This has been the first formal introduction to astronomy for countless students. Congrats, first of all, on this pending publication. Scheduled for June 30th, right? Well, we have the first copies. They've been printed, and they're just on a boat coming from China at the moment where the books were printed, but they were edited mainly in the United Kingdom. And you told me that this is maybe the only copy currently in the United States. Well, Alex has a copy too. So I think maybe there are two copies in the United States, but it's expensive to bring things by air and the bulk come by sea. But we're really very, very pleased with it. There is so much new stuff, new stuff in every chapter.

And the history of the book, and even before Alex joined me for auditions back, NASA once made a study of how their space projects were covered in the general public by looking at all the editions of my book that had been out up to that time. That's a nice compliment. It's only been six years since the fourth edition. I guess a lot has happened since then, right? What do you think are some of the highlights? Well, we've put the eclipse of 2017 on the cover, and there's a lot about the sun and the sunspot cycle as it goes up and down, at the moment very down, and discoveries with spacecraft that are being made about the sun, so we keep advancing that. There are certainly new things of interest in the planetary sciences. Curiosity is roaming around. We have the latest pictures from Curiosity.

around. We have the latest pictures from Curiosity. Cassini has spiraled into Saturn, and we have some great images and discussions of that. At the last minute, after it was all closed, I ran the Pluto chapter by Alan Stern, and he said, wait a minute, there's some newer stuff. So in fact, we went out to him and Crookshank and a few other people at the last minute. And the publisher really was getting angry with me for all the last minute things we were doing after closing. But we have a lot of statements about what the latest ideas about Pluto are. And we did get in a picture of Ultima Thule, which you and I were together at the flyby on January 1st. New Year's Eve, yeah. Yes.

In communicating extraterrestrial intelligence, there's new tries that have been made to sending a message out. But maybe the biggest thing as of this week is the question of how well the universe is. So – and Alex Filippenko, my co-author, was the only guy who was on both of the Nobel Prize teams for the acceleration of the expansion of the universe. the chapter about the Hubble expansion of the universe and whether there was a real discrepancy between the value for the age of the universe, the speed of expansion that we get from the Planck spacecraft, and the value we get from supernova observations. But it's a big thing now. There's a new article by Adam Rees there, and I'm at the Carnegie Observatories on sabbatical this semester from Williams College, and I see Barry Medore there, who's working with his wife, Wendy Friedman, on their values, which are now significantly differing from the Planck value, which requires a model to update the structure at the very early universe to what's going on now. So somewhere there's a problem, and it's looking more and more as though it's a serious problem. Challenging everything we had come to believe, or at least accept in theory, about our universe,

since that Planck constant is so basic to how we understand the universe. The Hubble constant. The Hubble constant, I'm sorry. I was thinking of the Planck length, so basic to how we understand the universe. The Hubble constant. The Hubble constant, I'm sorry. I was thinking of the Planck length, right? Of course, yes. Doesn't that just make this business that you're in that much more exciting? Well, sure, it's very exciting. And the Hubble constant, when Hubble was doing it, was in the 500s.

And then when I started doing my book some decades ago, there was a discrepancy between Sandage and Taman here in Pasadena with a value of about 100 and de Vogeler from the University of Texas at 50 or maybe vice versa, I think. But then there was a fight between 100 and 50. And now we're fighting between 74 and 68. So there's and precision is down to plus or minus less than two. So there have been tremendous advances, and we're talking about some details. And now that we're in this detail,

we can really test some fundamental ideas about the universe and how it evolved. I got another one that I think, I'm pretty sure made it into this new edition of the book, and that is the detection of gravity waves. Oh, certainly. There's a lot about LIGO. I was very glad to be here at Caltech on sabbatical when the LIGO announcements were made, and I watched from the auditorium at the astronomy building, astrophysics building at Caltech, which incidentally, for those of you who are spectral nerds, it's at 1218 East California Boulevard, and 1218 is the wavelength of the Lyman-Alpha line of hydrogen. So that's why they chose that. So anyway, there's a lot about LIGO, and I've been to the sites in Livingston, Louisiana,

and in Hanford, Washington. But when I left that wonderful press conference and comments that were being made that day, they gave us coffee cups and bumper stickers. So I was really sorry I hadn't hung around the print shop a couple of days in advance and they were making things to get a little advance notice. I have actually had to move some of the discussion of LIGO and the gravitational waves from the neutron star chapter, where it had been with supernovae, and move it into the black hole chapter, because then first we had the merging black holes. Actually, I've been working on the LIGO interest for decades, because I did a book called Invitation

to Physics with Richard Wolfson around 1980. And I visited Rainer Weiss at MIT at that time, and he showed me some of the equipment that was interesting, but he didn't really convey to me, or maybe I didn't understand, that the discovery was going to be decades off. I thought this was going to actually find the stuff at the time. Anyway, my wife and I went up from a meeting of the American Geophysical Union a year or so ago for my second visit to LIGO in Louisiana. And I found out why it's in Louisiana, because they wanted it as far as possible from Hanford, Washington. So first they looked in the East Coast. So first they looked in the East Coast, but it turns out that the waves of the Atlantic Ocean hitting the shore on the East Coast of the United States are so strong that the vibration would have been a problem.

And by moving it nearer to the Gulf Coast, the waves on the Gulf Coast aren't as strong, and it is an hour or two inland also. You know, we have talked about the exquisite sensitivity of those detectors, and apparently it's only getting better. I understand that they're online now, and they're getting a couple of events a week. Wow. It would have been enough to see the confirmation of these gravity waves that had been predicted so long ago by we-know-who Albert, so long ago by we-know-who, Albert. But does this also mean that someday you may be adding a chapter to the cosmos about gravity-based astronomy? Well, I certainly hope so. In fact, when I came out with my first edition before Alex came on,

there was a chapter on the outer planets. And then the next year NASA went by Jupiter, and the next year, Saturn, and I kept adding chapters. So now there's a chapter on Jupiter, and a chapter on Saturn, and a chapter on Uranus and Neptune. So I do like to keep up and expand on these things, and it's just been wonderful to follow the progress of astronomy in this time. More of our very special conversation with Jay Pasikoff is coming up. This is Planetary Radio. Forty years ago, my professor, Carl Sagan, shared his dream of exploring the cosmos with solar sails. The Planetary Society's LightSail 2 will soon become

the first small spacecraft to be propelled only by the light of the sun. I'm Bill Nye, and I'll be there as a rocket carries our craft into orbit. Tens of thousands of members have made this day possible. Already part of our LightSail team? Thank you. It's never too late to join us. Learn how at planetary.org slash join. What's new in solar astronomy? The Parker Solar Probe is going from NASA up close to the sun, and it's doing it in a gradual way, in a series of ellipses that gets closer and closer. So from my point of view as a

solar astronomer who studies eclipses, I've been trying to figure out the lines of sight that would intersect the kinds of matter around the sun that the solar probe is in at any given time. But we are able to get improved observations of the solar corona. And right now, I'm busy in getting ready for the July 2nd total solar eclipse that we're going to observe from Chile. that we're going to observe from Chile. I was very pleased over the last month and then technically, definitely yesterday, to get the confirmation of a grant from the National Science Foundation for three more years of my scientific study of the eclipse with my students from Williams College and colleagues from around the world. We will be in Chile on the center line, and four of the people will be at the top of Cerro Tololo at the observatory there at 7,500 feet. The corona is just different every time.

Maybe there'll be some eruptions. There were some a couple of eclipses ago that we could study. At this last eclipse, where we have these wonderful observations from Oregon, and we compare it with observations made at other places across the country. We can measure velocities in the corona and how quickly things change. We do see the temperature of the corona change over the solar activity cycle, what matches the sunspot cycle and at solar minimum the corona is a little a little cooler. We monitor that especially with some spectral lines from iron. In particular, back in 1869, a spectral line was discovered in the corona from iron that has lost 13 of its normal 26 electrons, and it had to be a million degrees to do that,

though it took till around 1940 for that to be figured out. And then there's another spectral line from iron 10, which is nine times ionized iron, so that's a little cooler. We can see the ratio of those two intensities change from solar maximum to solar minimum. I work with a very talented instrumentationalist, Aris Bulgaris from Thessaloniki in Greece, who has now modified a special filter that we borrowed from the Big Bear Solar Observatory here in California. And he's able to change the wavelength to match argon-10. That's nine times ionized argon, and that gives us an image of the corona in yet another temperature region. So we'll be trying that out for the first time from Cerro Tololo on July 2nd. I wish I was going to be there with you.

I thought I might be able to make it, but it's not going to happen. So have a typically wonderful time down there. Are we closing in on understanding the great mysteries about the sun, like why the corona is so incredibly hot. Well, what I like to say is that problem has been solved. And I've been saying for a while, the problem has been solved in 12 different ways by 12 different people. But actually, then I went to a meeting six months ago, and the speaker, Steve Cranmer from Boulder, gave a list of 19 different people who are different theories. So we're sure it has something to do with the magnetic field on the sun, which example, or what kind of little flares called

nanoflares might be doing it. It's something that we can test a bit. And one of my sets of eclipse observations that we made in 2017, together with a colleague from MIT, Mike Person, who had one of our filters in that coronal iron 14 line and iron 10 line, so-called coronal green line and red line, we observed several times a second. And the predictions of some of those theories are different, whether they're short periods or longer periods or no periods, if it's just those nanoflares going off all the time. So some of what we're doing at Eclipses is testing the theories that have been advanced and trying to distinguish among them.

You obviously have an endless, literally endless fascination with our star. I guess that's fair. It started back in high school when I was a member of the Amateur Astronomers Association in New York, although I am about to go next month to the 65th reunion of my sixth grade class from PS114 in the Bronx. And when we started having reunions for the 25th, they said, Jay, you're the only one who's followed through with his original plan, idea. So I have a validation that I really was interested, mainly from the Hayden Planetarium in New York, I guess, in astronomy all that time. And I found a picture from high school with a telescope I had built. When I went to Harvard

as a freshman, Professor Donald Menzel, the director of the observatory, was a distinguished astronomer who had observed many eclipses and studied the solar chromosphere especially, and he was giving a freshman seminar, the first in a series of freshman seminars that Harvard was trying to use to bring senior professors together with the elementary students. And it just happened that two weeks after we started my freshman year, there was a total eclipse of the sun that began over Massachusetts. And he borrowed an airplane, a DC-3 from Northeast Airlines, neither of which is in service at the moment, and took our freshman seminar along with a few friends aloft and started me off on solar astronomy or eclipse astronomy. What a great start.

You know, I have to ask, how many total eclipses have you observed now? Do you have any idea? Well, there are people who keep track. Bill Kramer has a website at eclipse-chasers.com. It does show, and I do have a list, this will be my 35th total solar eclipse that's coming up and my 71st solar eclipse, including the annulars and partials. Did you tell me once that you don't like being called an eclipse chaser? Well, the eclipses go at thousands of miles

across the earth. So I'm an eclipse preceder. And some people might say an eclipse enthusiast and my friend glenn schneider from the university of arizona has used the word umber file oh i like that yeah so i do like that there are some people who object to putting a latin root together with a greek root but as an umber file we've worked together on several things and i've sent him a lens to take on the eclipse flight that he has been navigating for out of Easter Island, and they are able to keep up with this totality for more than eight minutes, which is probably going to be the longest ever for an eclipse aside from that one Concorde flight in 1973. I remember reading about that.

Didn't they put a window in the fuselage of a Concorde? Well, it was a problem because, well, also, if you want to be competitive, as I am, did the people who were on that flight for 70 minutes actually see the Eclipsa where they just locked up in this tube, in this metal tube, with a few glances out if they could look through some instrument for a short time, which is basically what happened. I see.

But for that eclipse to be the seven-minute-long eclipse on the ground that it was, the sun had to be high in the sky. That had to be almost noon. So there were no windows there. They had to take this model Concorde, this experimental model Concorde, which was fortunately going to be retired. And they did put some quartz windows right in the top. And some instruments looked at that. And it flew from off the coast of Africa and landed in Chad. I did hear that they didn't have enough fuel for a go-round when they reached Chad. But the plane is actually now on display at Le Bourget Airport in France,

north of Paris, where there's an exhibit about that Eclipse flight, and there's an air and space museum. One of my most successful Eclipse events was was at the eclipse of 1970 in Mexico, where I went to an Indian village, Miwatlaan, south of Oaxaca, with Professor Menzel. And by that time, I was a postdoctoral fellow, no more just a freshman. And we had some very elaborate equipment at that time. And I've been contacted by some people from Oaxaca who are now arranging a 50th anniversary exhibition of related things there. And we had an extra geographic article at that time and we got some very interesting observations.

We did so well in that eclipse in 1970 that we decided to look ahead for the longest possible eclipse, which was this 1973 one that was going to be up to seven minutes and four seconds long. But at that time, there were not computer screens at which you could press buttons. So I got a map from National Geographic, and we pasted it on Professor Menzel's door. And I got latitude and longitude and plotted a path. And then I looked right in the middle for the longest place, and I looked for the nearest place to that, and it said Timbuktu. I hadn't even known that Timbuktu was a real place at that time.

Of course, it's a name that you use for things that are really too far away, which is also what Ultima Thule, incidentally, I discovered was used. It's something been in use for a couple of thousand years for something in the far, far north. Very appropriate. Very, very appropriate. So anyway, so Professor Menzel and I went to Timbuktu, or we went to Agadez first in Niger adjacent. And then we saw whether we could mount an expedition about an hour north of Agadez or an hour north of Timbuktu. He actually didn't come on the second

part of the trip. And we decided that we actually couldn't manage all the equipment we needed at seven minutes and four seconds. So he went to Mauritania, where there was six minutes and I think 20 seconds. And I went with the National Science Foundation team to Kenya, where we had over five minutes, but a better chance of clearer skies. And that was a major effort with a coordinated push by the U.S. National Science Foundation. So August 21st, 2017, I know where I was. I was in Carbondale, Illinois at Southern Illinois University in front of 16,000 people looking up at the only cloud in the sky that blocked most of totality. Where were you? And since this was obviously much more accessible than Timbuktu, for an observation like that, not just where were you, but what do you bring with you?

you bring with you? Well, first of all, I rely on my friend and colleague Jay Anderson, Canadian retired meteorologist who looks at 20 years of statistics of cloudiness from satellites. And he and I are actually redoing the Peterson Field Guide to the Atmosphere. And now for Houghton Mifflin Hartford. Another series of books that you've also done a regular contributor to. Well, I've done the Peterson Field Guide to the Stars and Planets. Yeah, that's yours. I took over from Professor Menzel, who did the first edition, and this is now the fourth edition. And this new 16th printing has some images from the eclipse in Illinois, in Oregon. Illinois, in Oregon.

But in any case, the best weather seemed to be clearest. Predictions seemed to be for Oregon. And we looked around to see where to go. And I noticed that there was a city in Oregon called Salem that I didn't know anything about that was right in the path. And then I wrote the professor of astronomy there, who was very hospitable. He said, come take a look. And then I saw that somebody I knew from graduate school had actually given a talk there recently. And it turned out he was Frank Bash, from Texas. He was an alumnus. Then I discovered that the president of Willamette University is, in fact, a pulsar astronomer, Steve Thorsett. So they were very hospitable.

And I went out there and we went and looked around and we decided we could observe from a balcony outside the math and computer science building where we would have some security, we would have some internet and some electricity. And in fact, later that day, I got an email from Glenn Schneider, my friend and colleague, who said, I was looking at Google Earth, and it looks like there's a balcony that you might go take a look at. And so even from

Google Earth, that turned out to be the spot. And in any case, we had a big group there. I now travel often with a travel group of tourists in addition to my scientific team and my students. And so we had a lot of arrangements there. I like to be able to sleep in the zone of totality so we don't have to worry about traffic and getting there on the morning of the eclipse. Which was a problem in Illinois, I can tell you. Well, and so we could walk over to our site. One of my colleagues at Williams College, who worked with us on a planetarium, drove a truck across the country for us with a lot of our equipment. So it was easier to get the equipment there than it is for Chile. We actually have shipped equipment this week from Williams College to my colleague David Slisky in Philadelphia, who is transshipping to the Kitt Peak National Observatory in Arizona,

because they will be packaging it with other equipment that goes to Chile, getting it through customs for us to go to the Cerro Tololo Inter-American Observatory. So we're already organized for the equipment there. But in 2017, we were able to just take a truck with a lot of telescopes and cameras and tracking mounts. You've been doing this for so long. Is it as exciting, as thrilling as the first one that you saw all those years ago? Oh, it gets more exciting now. They're just so fabulous.

And I keep trying to explain to people how beautiful they are and how important it is to get in the zone of totality. Yeah, you're not alone. So one of the examples I've given is imagine you go down to Yankee Stadium, after all, I'm from the Bronx, and you go down and you buy a ticket. And then you go home and somebody says, where have you been? You say, I went to Yankee Stadium. Well, that's a correct statement, but you missed the game. So to go to a partial eclipse is like going to the ticket booth, but not seeing the game. And then last month, I was at the National Museum of American History in Washington, DC. And you know what they have there? They have a 1920s ticket booth from Yankee Stadium.

How appropriate. I can tell you that one of our parting gifts for our now executive director emeritus, Lou Friedman, were a couple of seats from Yankee Stadium when he retired from his job here at the Society. Yes, Lou and I have reminisced together. So a fellow Yankees fan, let me turn away from eclipses for a bit, though not too far away. Where does astronomy stand among the sciences? There's an old joke when you're on a plane and you don't know if you want to talk to the person next to you on the plane for the six or ten hour flight.

And if you want to talk, you say you're an astronomer. And if you want to be kind of quiet and no questions, you say you're an astrophysicist. So astronomy very justifiably has a wonderful place in the public image. I don't have to tell you here at the Planetary Society about that. but the people are very interested in not only the planets, but also the universe beyond, and the things that have just been found over the last few years, not to mention the decades before or the century before, have just been fabulously interesting and continue to be interesting with the new planetary launches and Mars, another Mars launch next year from, well, several from different countries.

That's right, yes. Well, all this LIGO stuff and neutron stars and not to mention the black holes merging, there's just stuff across the board. has been the 100th anniversary of the eclipse that took place on May 29th, 1919. It was not long after World War I. And during the war, this strange German scientist, Albert Einstein, had an idea that advanced his earlier special theory of relativity that didn't include gravity, and he worked on an idea that did include gravity, a general theory of relativity. There was one young German scientist, Erwin Finley Freundlich, who went in 1914 to Crimea to try to observe it, and just as he got to the Russian border, World War I broke out, and he was interned,

and his equipment was seized, and they didn't observe that eclipse in 1914, which was a good thing in the history of science and the philosophy of science, because Einstein didn't yet have his final idea for what had to be in his theory. And when he kept working on it, a couple of years later, he actually doubled the prediction. And there's a very nice letter between Einstein and George Ellery Hale here in Pasadena, asking Hale if they could test this at an eclipse. And the idea is that when starlight comes near the sun, if it's near enough, it would be warped. It would be deflected by the warp in space caused by the mass of the sun. And then when you're looking back on your line of sight, the stars would appear to be slightly deflected. And in 1919, there was an eclipse with the sun in the Hyades, a star cluster. so there'd be a number of stars to test this on

if they could get these good observations. And Arthur Eddington, an English scientist, worked on this especially, and he ran an expedition to the island of Principe, which is now in the country, Sao Tome and Principe, it's off what's now Gabon, where we were for an eclipse in 2013.

And a second team led by another English scientist, Cromelin, went to Brazil. The Astronomer Royal, Frank Dyson, was the one who really coordinated the reduction of data when it was all over. data when it was all over. When the results were released in November 1919 at a joint meeting of the Royal Society and the Royal Astronomical Society, it confirmed Einstein's results, and Einstein became famous the world over with headlines and papers all over the world. Now, in recent years, there's been some doubts raised as to whether Eddington fudged the results a bit in choosing which cameras to use or not, because one of the cameras was out of focus, for example, and do you use those results or not? But this has now been carefully looked at, including in a new book by Dan Kennefic, and the result comes out fine. And Dyson was really in charge, not Eddington. And Dyson was opposed more

than favored. But the result really does back Einstein and has since 1919. And there have been endless tests of general theory of relativity. Since then, Albert stands up pretty well through all of these. And of course, now the detection of gravity waves. It really does make for quite a history. Do you think you could make the argument that astronomy may have been the first science? We may not have thought of it as science when our hominid precursors here, those who preceded us, were looking up at the stars, but certainly they were fascinated by the sky. Oh, yes. Astronomy has been very important. And in fact, to go back to my eclipse theme, you get an image of what we call a pinhole camera,

but that's just really any hole with something shining through. And the sun is round, so you don't notice that there's an image of the sun below a hole. But when the sun is partially eclipsed, then you see the crescent or the dip out of the sun. So the idea is a couple of thousand years ago, somebody noticed this imaging at an eclipse of the sun. And that eventually led to a pinhole camera and a camera obscura. And, of course, led then to photography and TV. So astronomy is at the basis of everything. You know, I never put those together, that series of developments, but it makes perfect sense.

Your love of astronomy's history has led you and your wife to the collection of a pretty amazing personal library. Who are some of the astronomers whose works you've collected? Well, when I was in college, I was scared to go in the Red Book Library at Harvard College. Pretty amazing personal library. Who are some of the astronomers whose works you've collected? Well, when I was in college, I was scared to go in the rare book library at Harvard College, the Houghton Library. But when I started getting some royalties from my textbook, I decided to see if I could get some books by the people who I mentioned in the textbook. So those are going to be the mainline astronomers like Galileo and Copernicus, et cetera. So I asked the librarian of the Rare Book Library at Williams College if I wanted to buy a book by somebody like Galileo, what would I do? And he said, well, we don't have any money, but Mr. Chapin has said that the library used to buy books from somebody in New York, or I called that dealer. And I said, if I wanted to buy a book by somebody

like Galileo, what would I do? The response was, well, I have a book from Galileo here. Why don't you come down to New York and see it? So that was the first book I got. And we're not talking about reprints here. We're talking about an original... This is the 1632 book, The Dialogo, which got Galileo in his final trouble that got him into house arrest, and that's what got my book collection started. And then I had known at Harvard from even my undergraduate years the astronomer Owen Gingrich, who got interested in Copernicus's anniversary year in checking on Copernicus books. And then a few years later, I asked him if I wanted to get

a Copernicus De Rufus Ionibus from 1543, what would I do? And he looked around the world with his connections and helped me get Copernicus at that time. So I have a few dozen books, but they are from the major people, particularly fond of the books by Galileo and Kepler and, of course, the Copernicus. So just as you were once afraid to go into the rare books collection, I would have the same fear. If you had brought one of these with you, I wouldn't want to touch it. Not just because I would be afraid that it would dissolve under my fingers and you'd never forgive me, but because of what that represents in the history of civilization. Well, one of the nice things of being at Williams College is we really are centered at our students. And I did now twice give a rare books course with a dozen students in the room. And we pulled out a bunch of these original things each of the dozen sessions each semester. So the students really do get to play around with the books. These are pretty

sturdy books. They had much better quality paper back then than we have now. So you can touch them. I invite you to come and see us in fact in Williamstown, I'd be glad to show you some books. Oh, I will take you up on that someday. I'm going to come forward several hundred years now. I love Walt Whitman, but that's in spite of him writing the poem called When I Heard the Learned Astronomer. I'm sure you're familiar with the poem. Well, there are two things wrong with Whitman. One is he's from Brooklyn and I'm from the Bronx.

So right away, there's a problem there. But I actually wrote somewhere a response to that poem. I very much object to when I heard the learned astronomer, because he makes the point from his point of view that all the calculations take away from the enjoyment of the sky. And for me and many people like me, knowing in more detail what the sky is like really adds enjoyment. So there's a riposte to Whitman's poem. The analogy that I always draw, and this is taking us in a direction that I was hoping to go, is that if you go into an art gallery, a famous art museum, the National Gallery, or whatever, the Huntington here in town where you're headed after our conversation, don't you get a lot more out of that art when you know about the life of the artist and you have someone who has studied that work talk to you

about the composition and what this object might have meant to the artist. Isn't it the same with science? I certainly think so, and I like to learn more about the details of what the paints are or what the background is. My wife and I went to hear the pianist Lang Lang on Sunday play with the LA Philharmonic. And we went to the session before in which the principal violist played on actually a viola that they brought from Germany that had been in the orchestra that Beethoven used. But we learned something about the pieces and the background. So I certainly do think we benefit from these things. The Whitman poem is not the only poem I object to. There's this annoying poem, Twinkle, Twinkle, Little Star, How I Wonder What You Are.

But so I've got a version, Twinkle, Twinkle, Little Star, Now We Know Just What You Are. And then some other people have written alternative versions also. So that's a poem that could be updated too. This has taken us in a direction I wanted to go. And I did not know that you would be bringing this other book, which is not quite out yet. And I read a little bit about online. Cosmos, the Art and Science of the Universe by Jay Pasachoff. And your collaborator on this one, Roberta Olson.

We were just looking through it a little bit before we started recording. This is an absolutely gorgeous book. And as listeners know, I love it when it's possible for us to bring science together with art on this program. Sure looks like that's what you were up to here. I've now been working with Roberta Olson for quite a while. She is a professor emerita of art history. She was at Wheaton College at the time, and now she's at the New York Historical Society, and we were brought together by Hallease Comet. She actually had been teaching art history and was talking about an image by Giotto of the Star of Bethlehem, and she noticed it had a tail. And so that was the discovery that it was Halley's Comet in the Giotto.

And, in fact, the European Space Agency asked her permission, I understand, to name their mission to Halley's Comet Giotto. Yes. It wasn't really her permission to give. So in any case, she came to Williams College to give a lecture in 1985, just before the main part of Halley's Comet. And we realized that we had similar lectures, except the last part of hers was art and the last part of mine was science. So we worked together all this time. We had grants in the 90s from the Getty Foundation to work especially on comets in British art. And we had a grant from the National

Endowment for the Humanities to go to Nuremberg to see the originals of the Nuremberg Chronicle, the drawings, the so-called exemplars. And we've written a number of papers and spoken at meetings over the years. And finally, we decided it was time for our magnum opus. So we have 10 chapters on different astronomical topics, comets or meteors or sun or moon, history of photography, galaxies. And so we were able to work with this very nice publisher, Reaction Books. We have some 300-plus photographs of artworkss mainly a few astronomical photographs too and we're really very pleased with the way it came out i'll say it again it is absolutely gorgeous i don't know whether it is more an art book or a science book and i guess that's a good thing yes yeah that's good anyway this is one i mean i get a lot of books i want this one but you said again

this is the only copy in the country? If I had more than one copy in the country, I would give it to you. We'll see if we can get one later from your publisher. Who is the publisher of this one, by the way? It's called Reaction Books, which is a London publisher. It's distributed in the United States by the University of Chicago Press. And Cambridge University Press is once again- The textbook is Cambridge University Press. And just to have a URL that's easy to remember at solacorona.com,

I have a link to various books that I've done. You've received so many awards, more than we have time to mention here. The last major one, at least that I read about, maybe there's something else that wasn't documented. Two years ago, you received the 2017 Richtmeier Memorial Award from the American Association of Physics Teachers, quoting now, for outstanding contributions to physics and effectively communicating those contributions to physics educators. You continue to serve and take leadership positions on all sorts of bodies within all of science, working in formal and informal science education. Why have you devoted so much of your life to writing and other ways of sharing this love? I mean, you could have just gone off and, you know, published a paper now and then about what you were learning about the sun,

but you've done so much more. It's just a matter of doing what's been interesting. I've always been interested in communicating what we've been doing. In fact, when I was a graduate student, I spent time as a non-resident tutor at Kirkland House at Harvard College working with undergraduates. And as I recall, I was in fact called in at one time by the director of the observatory, the chairman of the department at the time, and why wasn't I devoting 100% of my time to my thesis. But I did write an article on the sun for volume one, number one, issue number one of Astronomy Magazine, for example. And then at one point, the later chairman of the astronomy department thought of me when there was

a job at Williams College that came up. So I've been very fortunate to be able to do what I have liked most to do and that's involved not only doing some research on astronomy but also in talking to people about it and taking students with me on expeditions. Interesting that you have that in common with your former professor at Harvard, Carl Sagan, that both of you at one point or another got in a little bit of trouble for being a little distracted and going, as they saw it, too far afield from your field. There's another astronomer you've mentioned a couple of times, and because you have returned to Pasadena, I just want to get your thoughts about that pioneer who also liked to share his

love, George Ellery Hale, who had such a huge role, not just in astronomy, but in this region. Yes. Hale not only founded, but for a while was called the Hale Observatories, and now the Mount Wilson part run together with the Magellan Telescope in South America. It's not called by that name anymore. But Hale built a laboratory in Pasadena, now called the Hale Solar Laboratory, in the 1930s and did observations from there when he was no longer able to go up Mount Wilson. In his home, right? Well, no, actually, he lived elsewhere, I discovered. The current owners live on that property, but that house was built later. Hale actually lived elsewhere and had this laboratory

adjacent to the Huntington Library. It was at Huntington property. Hale convinced Huntington to come here, and Hale played a role in founding the National Academy of Sciences, based in Washington, and a role in the International Solar Union, which morphed into the International Astronomical Union. So Hale was a big figure in doing that. And his grandson, Sam Hale, who's an old friend of mine, is now the head of the Mount Wilson Association, which is bringing Mount Wilson to the public. In fact, my wife and I are going to a concert in the 100-inch dome in a couple of weeks. And an artist has put a set of prisms on the 150-foot solar tower that puts a solar spectrum down to Pasadena, and he can direct it to various places, even quite further afield.

No kidding. We're within sight of Mount Wilson. We could arrange that on a clear day. Let's see if we can do that here in the parking lot at the Planetary Society. You have given me very good reason to make another pilgrimage up the hill here in the parking lot at the Planetary Society. You have given me very good reason to make another pilgrimage up the hill here from the Planetary Society to Mount Wilson, one of my favorite spots on Earth. I am so glad, though, that you were able to come here to our headquarters, Jay. Thank you for doing this.

And may you enjoy many more years, not only of astronomy, but as a wonderful ambassador of science and astronomy. Well, thank you very much. You're very kind. And it's been my pleasure to know you for a while and to know the people at the Planetary Society, including Carl and Lou Friedman and other people who were involved, now Bill Nye, Bruce Murray earlier. It's just wonderful to have this gospel of astronomy spread so widely, and the Planetary Society is being very helpful in that. Amen to that. Thanks again, Jay. Time for What's Up on Planetary Radio.

So we are back with the chief scientist of the Planetary Society, Dr. Bruce Betts. Welcome back. Thank you, Matt. Bruce Betts. Welcome back. Thank you, Matt. Good to be back. How are you doing? Great. And you haven't heard it yet, but we had a good conversation with Jason Davis earlier in this week's show about the current status of LightSail and the difference between LightSail 1 and LightSail 2. So all good stuff as we lead up to that launch on, we hope, the 22nd. Jason, who? Ha, just kidding.

What's up? It's Focus on Jupiter Week because Jupiter is at opposition. So it's on the opposite side of the Earth from the Sun. So at its closest point, not that it varies hugely, but it's a good time to see it. It also means that it's rising in the east around sunset and setting in the west around dawn, and you can check it out looking like a super bright star in the east in the early evening. Saturn coming up a couple hours later in the east looking yellowish, but let's focus on Jupiter this week, shall we? All right.

I wish I could have focused on it. It's been so overcast here almost every night that I've missed out. Damn it, man. Would you fix those clouds? I can fix the clouds, Captain. All right. On to this week in space history. It was 1985 that the Soviet Vega 1 spacecraft released a lander and a balloon into Venus. So that was kind of groovy.

Vega 2 joined it shortly thereafter. And I know that there are still people who want to send balloons back to Venus, right? Oh, yeah. Oh, yeah. I think we're ready for Random Space Fact, and I do have a celebrity intro for you. Hi, Bruce. This is Jay Pasikoff. What's this week's Random Space Fact, please? Excellent. Thank you, Jay. We're going to fly a light sail. I don't know if you heard about that. Oh, wait. Yes, you did. It's a solar sail, and people often get

confused because we talk about solar sailing. They think we're sailing on the solar wind. We're not. We're sailing on light pressure, the photons pushing against the sail. But let's talk about the solar wind, shall we? Because it's kind of amazing. The solar wind reaches speeds of 250 to 750 kilometers per second. Wow. Per second. It's really zippy. It's even faster than light sail. Yeah. For now. For now. Well, for light sail, too, I'm pretty sure it's going to win.

So let's move on to the trivia contest. I asked you to name everyone who served as NASA administrator more than once. How'd we do, Matt? It doesn't take long to answer this one, because as most people figured, we've only had a couple of administrators who served twice. So see if this matches your research. They were Dr. James C. Fletcher, who served from 1971 into 1977, and then again, 86 to 89. So quite a separation there. And Dr. Alan Loveless, who served in 1977 and then again in 1981. Both of those times, Loveless was serving as acting administrator, while of course, James Fletcher, one of the better known NASA administrators who was a full-fledged not acting, but the real thing administrator.

There you go. That all sounds right. I call them Grovers. Obscure U.S. presidential reference. Oh, interesting. Grover Cleveland. There it is. I'm very happy to say that Matt Minter, a first-time winner, even though we've been hearing from him for years, very much like last week's winner, Mel Powell. Don't forget Mel. Matt, you are going to be the happy winner who gets a 200-point itelescope.net account, and a Planetary Society kick asteroid, rubber asteroid this week. Congratulations. And I said, don't forget Mel, because sure enough, Mel in Sherman Oaks, he submitted this.

Who knew NASA had such an accomplished drama department? So many acting administrators. Nah. drama department. So many acting administrators. And then he added, sorry, Dr. Betts, for the groan you'll unleash if Matt reads this one. It's my own personal permutation of a groan. We're ready for a new one. We're going to bore down into light sail spacecraft trivia. What is the name of the alloy that the light sail spacecraft booms are made of?

The booms that pull out the solar sail. They are made of a kind of a weird alloy or tell me what it's made of. But I'm looking for the name. Primarily go to planetary.org slash radio contest. It's not unobtainium, I don't think, right? Oh, dang it. Now I need a new question. That would help them deploy because they have an anti-gravity property that James Cameron,

never mind. You have until the 12th. That would be June 12th at 8 a.m. Pacific time, Wednesday the 12th, to get us this answer. And somebody is going to win. I can almost guarantee it. Somebody is going to win a 200-point itelescope.net account worth a couple hundred bucks on that non-profit worldwide network of telescopes. And we'll do a couple more of these, but we're getting near the end here for a while. Another chance to win yourself a Planetary Society rubber asteroid. And let us also throw in from that library of books that we have. It's Chasing New Horizons, the terrific book about the mission of New Horizons by Alan Stern and David Grinspoon. I think they've just come out with the paperback version of it.

And they sent us one of those. And that one can be yours if you win the contest this week. That's it. All right, everybody. Go out there, look up at the night sky and think about all the photons bouncing off your head. Thank you and good night. Not doing me any good, I'm afraid. I don't feel any thrust and it's not growing any hair.

So anyway, he's Bruce Betts. He's the chief scientist of the planet. Not doing me any good, I'm afraid. I don't feel any thrust, and it's not growing any hair, so... Anyway, he's Bruce Betts. He's the chief scientist of the Planetary Society, who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by our starry-eyed members. Mary Liz Bender is our associate producer. Josh Doyle composed our theme,

which was arranged and performed by Peter Schlosser. I'm Matt Kaplan, Ad Astra.