NOVA; To the Moon; Interview with Gerald J. Wasserburg, Professor of Geology and Geophysics, Emeritus, on the John D. MacArthur chair at the California Institute of Technology, part 1 of 3

I said there were two different Apollo's, there were three different Apollo's. There's the Greek God Apollo, who was quite a formidable character. The other gods didn't easily meet in his presence, they couldn't quite handle him. There is the Apollo, which is the achievement of this nation and of people in the world as a whole, in landing for the first time on another planet. And then there's the Apollo, which represents science. And these are really very, very different critters. Let's talk about the site selection, okay. Let's talk about, after 11, you said there's extreme importance to collect samples from a variety of sites. Did we go to enough sites? No, we did not go to enough sites. The problem was that we probably couldn't. And there are problems of grave danger, for example.

I always felt we should land in a highland site. But the site selection was a very interesting and amusing thing for which I have very bad feelings. This everybody had believed this result that there would be young lunar rocks. And so even up to Apollo 17, there were some rather chagrin individuals when the age of Apollo 17 was not very different from that of Apollo 11, or 12, or 15, or 16. And people were looking for young volcanoes. But there weren't any young volcanoes. Somebody turned off the burner three billion years ago. So what was the problem with the site selection? Was it too risky? Was it? One is extremely important to land in the highlands, but those are not easy landing sites. To land on the backside would have been enormously important because it is a great, big crater. 800 kilometers across, which is covered as a big bite of the backside of the moon. But that places the spacecraft out of a direct line of vision and communication with the earth.

Which non-trivial thing, and the poles would have been extremely important to find out what is the positive in the poles. So I think the problem of highland samples is in the oxenile basin, our major issues, which require them. And the highlands are the things with the very oldest material in it. Other places we could have gotten that we didn't go that frustrated you? No, I think the sampling really was, when it was all over, was pretty good. I think there were specific details, which were very hard to accomplish. But if one looks at the information that has come out, the site selection almost didn't make any difference. That is, people went to sites for reasons which had nothing to do with what was true and followed up pursuing fandoms of what they imagined from their geologic maps. But the results were that the impact debris has shown a showered material from vast different areas.

And some of the sites like the 14 and the 16 site really brought back distinctly remarkably different material than the other ones. And so the moon provided, I think, with some general good judgment in sampling sites and enormous variety of material. So what did we learn? How old is the moon? Well, moon. How old is the moon? That's, we're arguing about that now. The moon is about, more or less, exactly as far as we know, the same age of the earth, which is about 100 million years younger than the solar system. So it appears that the moon and the earth have a funny relationship, which had been guessed before by Laplace, I think, and that they were formed as later planets were. And currently the major ideas are that the moon was formed by an impact of a other planet about the size of Mars, hitting what was then the proto-worth and blasting everything

out, leading behind what's left of the earth and the moon without an iron core. And now there are new evidence from the beautiful work that Lee and Holiday did, which showed that in fact some of these projectiles are even preserved inside of the moon today. And that is now found out from the lunar samples collected from the Apollo missions looked at nowadays, which are now changing our views of what major impacts are like and the evolution of both the earth and the moon. What does it mean that the moon is layered in not uniform? What does that tell us? It's a basic geology thing here. When things started, there's Harold Yuri, because of the mean, at the moment of inertia of the moon and the mean density, had believed that the moon had accumulated as more or less cold object and was a passive object just preserving early solar system history. From the results that Turkavitch got with surveyor and then the spectacular results that came

from the Apollo missions became clear that the moon at A had really been melted. The melts were not all triggered by impacts, but they were due to internal heat source and things had to be moved from the interior of the moon to the outside of the moon. The moon has debris in the surface which formed very rapidly by melting of the moon early and this then continued for about 800 million years a little bit more than that now. Which mission do you think gave us the most best data science wise for you? Which mission gave us the best science data? I don't think that's a good question. I think the biggest mission was 11 and the reason it gave us the most science data is we were the most ignorant. The questions that we asked at 12, 13, 14, 13 we did too well with the samples, well that's another story, but the remaining missions now had a basis for addressing the questions. If you just had one and you did your homework which was the case of Apollo 11, then that

set the stage for what the issues were. What was the significance of the basaltic rocks from 11? Well the significance of the basaltic rocks were basically confirmed that there were melts formed inside the moon which made basalts which is kind of straightforward more or less and that these objects were not old and not young. They were much older typically than the oldest rocks you find in the earth that is 3.8 billion year old rock on the earth is not a common object and the moon gets standard. I would change the question and try to make the following statement. When we had, we as a scientist of a community not to meet with you and me or Grandville Turner or any particular individual, but we as a community had these materials. We were then faced with a different game than had ever been done before and we how can

we maximize the inferences to be drawn from the materials. And that was the magic of Apollo. We had gone on from saying, I will date a rock or I will tell you this about the composition of this. To relating these observations some of the deepest questions of planetary evolution. And that really is what came out of Apollo that suddenly one didn't simply say, have a date honey. Then he said, now you must do this to the planet and then you have to do this to the solar system and these rules which we really had in the back of our minds are now useful and valuable tools in the most important way. I remember a phone call after Apollo 11. I get a phone call from Harold Clayton Eury, my thesis sponsor and hero. And we're not supposed to say anything about what we have. He said, I understand you've got an age on the lunar soil. We had one little while with some powder and we picked one little crystal out of that powder.

Not much bigger than a big salt crystal from a salt shaker. And I said, well, either the moon is very, very old or the rocks in the moon are very, very old or the moon has no alkali elements in it. Well, he liked the first story. He didn't like the second story. The second story was the one that was true. So we then began to generalize things in a fashion which we had never done before and all of us as a community began to do that and the conclusions were firm. They were robust. And are basically the tools by which we approach how solar systems are made. Now planets are made now. That's different. Great. Yeah. I'm going to take one. Earth takes three. In the old days, and even today, you had the problem of hot moon or cold moon. Cold moon was the case that Harold Eury had promulgated of you as an object, accumulated from debris, made the small planet the moon, and it was cold. And basically, nothing has happened to it.

There are other people who said, no, if you have a planet and you get it hot, then it's going to be continuously active with volcanoes and all sorts of activity, just like we have on the Earth. And that was the issue was immediately addressed when we went to the moon and got samples back. Well, the answer was neither of the above. Maybe it wasn't, certainly, absolutely was not cold. And it was hot, but it cooled off. And then we were faced with new dilemmas, namely, how do you take a planet-sized object, have it hot and active doing all these things, making volcanoes and differentiating and melting and moving material up and sinking some stuff down, and cooled it off. And that was the controversy, the basic question, then, was not hot or cold. They may live forever and keep churning, churning like the Earth does, or be cold and do nothing. As most meteorites appear to do, now we have a dynamical planet with a characteristic lifetime, and it's that now which requires addressing as to how you get something hot

and then you turn it off. Great. I don't know all that. That's good. Yeah, that was good. Take one. How many verses on manned? A lot of people said, what a waste of money. Well, it depends. I mean, man versus un-piloted versus un-piloted, since now we have female astronauts, just like Caltech used to be in all boy school, but it isn't. And that's a good thing for intellectual reasons. The was before Apollo started, when it was being first considered, several of us wrote

a telegram to the President of the United States pointing out that the scientific returns could be accomplished at much lower price and more efficiently be by doing it unmanned. But if you think of the two Apollo's which I described before, not the Greek God, but Apollo as an enormous human accomplishment in the broad sense, that requires a human presence. The scientific thing does not, in my opinion, require a human presence. And it is the balance between these two, which one has to look at. I've written several documents on the subject and I would say the following thing. First, we should send robotic vehicles where people cannot function well. And we should send people where people can function well.

In space for the most part, people cannot function except as part of robotic human interactive relationships. There is no fresh air in empty space, whereas they're shielding from the cosmic bombardments. So the question of piloted versus unpiloted robotics, I think that the major advances can be made using robotic systems for exploring much of the solar system. That we get tied up in imagining the human presence going out, such as the program that a previous administration had brought forward of man-based on Mars, which was a presidential announcement, where the costs are enormously high, they're all spent on Earth, but that you place humans in the position where they, in fact, really cannot properly function. But on the moon, was it useful to have observers up there, people collecting samples?

Honestly, no, you need devices making observations, and there are many things that we should return by the incredible sensitivity and acuity of the astronauts about which I can do nothing but applaud. But if you back off and ask a priori, is it really required to have a human being make that decision? The answer is, in some cases, yes, but in many cases, no. All right. It's going to make you the unpopularist could be, but that's... What did Apollo teach us about the Earth? What did the work we did on the moon teach us about the Earth? That's really my kind of... If we now look at what we do in the Earth's sciences in trying to understand the Earth, and look at the technologies and intellectual approaches that were developed for Apollo, we'll find that that, which goes on on the Earth today, is, in fact, a direct, not indirect, an absolutely direct consequence of the skills developed from the Apollo missions.

For example, we have been worried about climate change in the Earth, and worried about the times where climate changes occur over a past, say, several hundred, few hundred thousand years. The techniques which we use to do this and the approaches are those which were developed for Apollo. What do you think about the findings today about finding water on the moon, and should we go back? I think the finding of water in the moon has still not been published in a fashion which has made it a fully defensible thing. I have to worry about how much hype and how much factor are in Jim Arnold and I have a bet, and if I'm wrong and he's right, which appears to be the case, I'll be glad to pay him off on that. I think that the lunar poles are an extremely important place to visit. With that, I have absolute and complete accord with him. The highlands, however, it seems to me, are the place and the backside of the moon are

a place which I would like very much to see us visit either robotically or with pilot missions. Why? I think that the question of where the older material is in the moon is quite critical. When we have the earth and the moon formed at the same time by one process, or at least disrupt the earth by a major planetary impact, we would like to find more and more direct evidence for that. There are things hidden in Apollo, such as the stuff that Tatsumoto worked on, the wonderful orange glass soil found by Jack Schmidt. That stuff's always been weird. It's disturbing. It showed that there were volatile, rich materials, uranium pour inside the moon, which was uranium rich. And we always kind of buried that under the rug. But the new discoveries by Leon Halliday saw that, in fact, this may be the relic of the original Mars-type body, Earth-impact.

I think that the hope of clarifying those issues would be very, very good reason to go back and find this old material. Terrific, we just touched briefly on Harold Yuri. What was Yuri's idea about the moon? Was he right? Oh, I don't ask you. I'd basically said he was wrong, but you want me to say something about Harold, sure. We're ready to say something else. Harold Clayton Yuri was one of my two thesis sponsors, Harold and Mark G. Ingraham. Harold was the person with an intellectuals and scientific and public stature that could focus on the origin of the solar system and the planets when all these astronomers were looking away at galaxies. He used the moon as a test ground for his models and said many things, which were quite correct, and many which were absolutely wrong.

But the intellectual vigor and insight and the formulation of the issues are the same problems we work on today, and I think that kind of a guidance principle from one person is an enormous compliment. The importance of those samples and how protective you are of the room, how important was to build a good room? This is the ending question. You spent a lot of your time on that. Why? Why? Why was it so important to get it right? When you are attempting to infer something very important about a strange and wonderful object, you are not interested in analyzing your toothpaste, the ashes that fell off from there. We are now in the process as a whole field, not just my colleagues and my students and myself, the whole field of making enormous discoveries on microscopic objects. And the problem is to disentangle that, which is local contamination from the intrinsic

thing, which we see there. Let me give you an extreme example. Many of us are now measuring individual grains of star dust. These are little grains much more than a human red blood corpuscle. Maybe take 10,000 of these grains to fill a red blood corpuscle, which came from another star before the solar system was made. Our problem is to disentangle that from all of the other debris which has been processed or contaminated. In the case of the moon samples, the effects to some extent could have been greatly diminished or obscured if they had been contaminated. And so when you really are trying to find out what is the true source of any problem or any character, the ability to eliminate human contamination or local contamination from the true answer which you want, which has to come from the material that came from that source. That's the key. It started this as an extreme example, because these are very small particles, with very exotic.

Did the astronauts contaminate the material when they were... Of course. Tell me that. Well, for example, one asked a question of what is the organic content of lunar material? Well, that's kind of hard. First place, there's almost none. And the organic material, like astronauts, is organic. What the boxes were clean for the LSRC's to put the lunar samples on. If you don't clean them the right way, you can use, for example, lard to polish the inside of the aluminum case, and that's a hell of a lot of organic material. It's about more than you'd find in 20 tons of lunar rot. So I think the real issue is that when you attempt to find out a class of problems, you have to avoid the contamination from things which are going to obscure the results. And that's the heart of the matter, and that's what one has to do. Let me ask you another question. How did you come up with the name, sorry? The lunatic asylum.

That was in this particle on science. And it was time to publish the results of the studies that my colleagues and students and I had done from Apollo 11. The question is, what should authorship be? Because you are only permitted for printed pages in the journal, independent of laboratory. Well, as the founder, director of the laboratory, I would start with W, for example, and I would be the senior author, and I would get the credit. But there are incredibly skilled, brilliant imaginative, hardworking people who had done all these things. And then you could put alphabetical, which is kind of not too swift. It doesn't look like anything either. And all of us were affected by the moon. And we were working in order to understand the moon. That was really an obsession which we planned and worked on for years before. And for, in fact, we're one of the few laboratories in the world that had actually planned to do this from the beginning in order to do the proper job. So we had to have a name, my machinist, Kurt Bowman, who was built the first spectrometer

here, which we designed to meet with Papandasas, he and I designed with him and with Emil Victor Niel, he put a sign on it, which he scribbled on this big bar, lunar tick.