Oral History Transcript — Dr. Allan Sandage
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Allan Sandage; May 16, 1974
ABSTRACT: In this interview, Allan Sandage discusses his career and the history of the Hale Observatories. Topics discussed include: astronomy; cosmology; Mount Wilson Observatory; Palomar Observatory; Edwin Hubble; Walter Baade; Rudolph Minkowski; expanding universe; Fritz Zwicky; red shift; Willem de Sitter; Friedmann solutions; Milton Humason; stellar evolution; H-R diagram; Martin Schwarzschild; Hermann Bondi; virial theorem; James Stokley; Aldous Huxley's "Young Archimedes"; University of Miami; California Institute of Technology; Richard Feynman; service in the Navy; Richard C. Tolman; Jesse Greenstein; Morton Roberts; Crab nebula; photometry; S. Chandrasekhar; Mario Schoenberg; quasars; Thomas Matthews; Owens Valley Radio Observatory; globular clusters; Cepheids; J. P. Ostriker; black holes; JŠnos Bolyai; W. K. Clifford; Knut Lundmark; Ralph Kronig; Wolfgang Pauli; George Uhlenbeck; Las Campanas Observatory.
Wright: This is an interview with Dr. Allan R. Sandage, by Paul Wright on May 16, 1974, at the offices of the Hale Observatories, 813 Santa Barbara St., Pasadena, California 91106.
I have read a little bit about your early interest in astronomy as a child Ė something to the effect that you had disturbed the neighbors at three oíclock in the morning with your activities in the back yard.
Sandage: Where did you read that?
Wright: In the Scientific American Ė a little biographical sketch. I think it would be very interesting if you would relate some other little anecdotes like that.
Sandage: Yes, but thatís really not want you want. You donít have a biography of me. What you really want, somehow, is the history of this observatory and what it means to cosmology. Maybe we can get into this personal business a little later. The crucial thrust of what has happened in cosmology was a series of discoveries fifty years ago. I am a very interim character, interim in the following sense, that when I first came to what is now called the Hale Observatories, and used to be just the Mt. Wilson Observatory, and then Palomar came into the scene. All these people like Hubble, especially, and Baade Minkowski were here, and these guys were the ones that established the whole framework upon which we are understanding science now, in which astronomy really has been set, and any observational cosmologist at the present time cannot expect to discover anything as fundamental as was laid down in the 1930-1940s, so really thatís where the story is, the history of this place in the last forty years, starting ten years ago. Now, Iíll be willing certainly, during the course of the afternoon, to tell you a little bit about my work, but thatís probably not the way you want to start off.
Wright: Well, I think that we almost have to depend on the written record for things that went on in the 1930s.
Sandage: Well, what is the written record now? How much does the public really understand? Well, you as an historian, can you trust Macaulay for example in History Of England, or can you trust Ė oh who am I grasping for Ė Toynbee in his statements about the Catholic church for the Protestant church or the Reformation, because every historian has to stand someplace —
Wright: Has an axe to grind —
Sandage: Yes, in a sense, thatís right, thatís right. Itís an opinion situation, where science is not opinion, and youíre asking me for really an historical account of cosmology which is my opinion, and Ė well, maybe what you say is absolutely right. There is a written record, but that written record is also distorted. You canít really believe everything you read, and thatís true in science too. There are some great super salesmen in science, and some guys that have the answer that didnít write it down, and every era has those, and so you as an historian must really somehow weight what your own personal viewpoint is, so you say the written record is clear in cosmology. Well, it is, but let me then ask you what you think the history of cosmology has been?
Wright: Wel1, I would say this, that perhaps Helen Wright's book has delineated to some extent the life of Hale, which has been very crucial to the history of cosmology.
Wright: But unfortunately most of those people who were involved areno longer with us.
Sandage: That's right.
Wright: And so I think it —- perhaps some kind of recording of an interviewwith George Ellery Hale would have been very informative.
Sandage: Or with Hubble.
Or with Baade, or with Humason — these guys may beÖ
Wright: I know that Hummiston only recently passed away.
Sandage: Passed away, that's right. So that I came to the observatory at a very interesting juncture. It was after the second World War and the fundamental discoveries had been made in the previous twenty years, and they were not really — or the people were not really — had not really recovered from those discoveries, in a sense. They were so epoch-making, so incredibly important seen from the view of the last sixty centuries, that when you're making them, and when you come to a place — when that's happened, there's not been enough time to stand back and assess what had happened. But now it's coming to the point that one can assess what happened in the 1930's and 1940', or 1920's — late 1920's in this field of cosmology, and I think that what's going to happen is that the historians four or five hundred years from now are going to view what happened from 1915 to 1940 in Southern California., in Pasadena, in the same way that they viewed what happened on the island off the Danish coast at Tycho Brahe and what happened with Keple in Prague, and what happened with Newton sitting under the apple tree. Within a period of a hundred years, the whole of science or mechanics which developed into physics started in that time, three hundred years ago, and the same thing now has just passed in cosmology and this is where it all — all really happened, so itís really very strange for you to come and ask right off what I did, because nobody can do what Hubble did. Hubble found the universe — he found the universe. You know what that means? That means he for the first time understood what the large scale structure of matter was. Galaxies exist, instead of everything in a — in the Milky Way. He not only found the universe, but he found what the constituents were. He found they were galaxies. How did he do that? After showing that Andromeda was an island universe, was a galaxy, he then looked at all the other white nebulae, and he counted these things, and he found by counts to successive limits of magnitudes that, by golly, they increased at six-tenths times the apparent magnitude, the logarithm of the number per square degree increased at six-tenths times the apparent magnitude, and only things that are uniformly distributed in space would do that, so in one fell swoop he showed in 1934, which was ten years after he discovered galaxies, that these things were distributed uniformly to the limit of what could be observed. But thatís not anything what he did yet. He found that the whole schema was in a state of expansion. Now thatís something, isnít it? So what could we do beyond that?
Wright: Can I interject a question at this point? Would you say that Zwickyís interpretation, or I should say, lack of interpretation of the red shift as being a genuine Doppler recession was, was what would you say, sort of a conservative reaction against a radical new idea the way the universe is structured?
Sandage: Thatís a very interesting point. For people here at the observatory, no one really had taken Zwicky seriously at all, and I think that essentially was the case until more development in physics in terms of neutron stars and super-novae came along. Thereís no question about Zwickyís role in those areas, but the questioning of the expansion of the universe by ad hoc theories which have nothing in the realm of really deep physical theory — now by deep physical theory I mean a theory that inter-connects with other things, and one really knows when you have theory and when you have speculation — I mean you as a physicist know the difference between speculation and what it really means to write the Newtonís equation and solve for the motion of a simple pendulum, or write Lagrange Equations down for a more complicated system. Thatís really real. Thatís the way the world is put together, and so you go to various lower levels of speculation from those really very deeply connected things, and Zwickyís ideas and other peopleís ideas of tired lights, of all sorts of things like drag of light. Theyíre just statements of the same problem without anything behind them really. So no working astronomer every takes speculations like that seriously. They may get in the public press, but thatís not science. That may be the beginning of science from which one can develop, but no one has really developed anything for twenty or thirty years from those ideas.
Wright: So what you would be saying would really perhaps Zwicky had a subjective prejudice against the idea of expansion and this is what led him to formulate the ad hoc hypothesis?
Sandage: Well, itís terribly difficult, in fact impossible to know what motivates anybody. I mean youíre asking for motivations. All one can really read, and you as historian must appreciate this more than anybody, what somebody says, and you know whether they say it with a twinkly in their eye and are leading you on, or whether they really, really believe what it is that theyíre saying. (laugh). And I think that the speculative ideas just may be the beginning of science, but theyíre not science. Theyíre just no science. So, itís still quite true that thereís no true fundamental proof that the red shift is a Doppler motion, but every test as if it were a Doppler motion has checked out right, but that still doesnít mean there may not be an unknown principle of chemistry or biology, but thatís not what scientists do in the laboratory.
WL The reason why I asked the question was not to test your, test your interpretations of the red shift, but more to get at the motivational questions, because in the history of science, as you say, certainly all you have is a record that you can look at, but one of the more fascinating aspects of the history of science is to try and speculate, upon the motivation that led people to do the things that they did.
Sandage: Well, O.K., O.K. Motivation — there are two levels of motivation. One level is, you do things you think other people are interested in Ė Now do you that because if you think youíre successful, somehow itís a game for you. Now most people donít say that, but I really believe that no scientist or no creative person works in a vacuum. Beethoven probably would not have composed anything if he knew he were the only person on the face of the earth, so there are all kinds of questions like that that everybody asks themselves, but the other really strong reason you do something and spend your life doing it, is a deep motivation out of fascination, and I think thatís a stronger one although it occurs Monday, Wednesday and Friday, and this coupling with what other people think maybe occurs in some people one day a week or maybe one day a month, or maybe seven days a week, but you ask now what motivated Zwicky. Well, I donít know what motivated Zwicky. I donít know what motivated Hubble, except Hubble has something real that he could test, and it proved to be correct, and for every lead in that direction there are a thousand leads that go astray. So he was not only lucky, he was intuitive. He was very, very aware of the power he had from the telescopes and he used that in a way nobody else has every used it.
Wright: I did not intend by asking that question in any way to deprecate Hubbleís contribution. The reason I raised the motivational issue is that many debates in the history of science professional hinge upon why somebody did or did not do a particular thing at a time.
Sandage: Yeh, Well, generally you do the thing that you think you can do, at any given moment. Thereís a time thatís ripe in almost all science for certain crucial and often not crucial experiments and you do what you think you can at the moment. As science progresses and a person progresses, so that Hubble in 1920 could surely not have found the expansion of the universe. The time wasnít ripe, and also the observations werenít there. But you mean it in a slightly different way. You may mean it the way James Dewy Watson did, with Krick the D.N.A. when Rosie Franklin, or whatever her name was, was doing the same thing and there certainly was some pressure — some race involved, and the race for priority just canít be denied among scientists no matter what they say, priority does motivate a large amount that is done, but thatís not so bad in a certain sense if you really believe that the good thing is the final goal. Socrates may have wanted to impress all the people in the village square, and he sure did that, but because of that weíve got those magnificent dialogues. So, I think itís bad to pass judgment on that aspect.
Wright: You made one remark there that perhaps got more at what I had initially intended by my questions. You made the remark that at the observatories at the time, when Hubble announced his results, and presumable they were fairly well-known amongst the staff prior to their publication.
Sandage: Yes, thatís right.
Wright: Zwicky's criticisms over the last years concerning alternate explanations of more conservative approaches amongst the professionals have not been taken seriously. That is, they themselves did not start new trains of investigation from a number of other sources. They were not seeds by which new directions were made. Thatís not to say I think there were not tensions over the public criticisms of the prior work, but you have to also realize that an awful lot of people were actually looking for this same effect that Hubble found. Now, why were they looking for it?
Sandage: You know from your reading that there had been predictions by de Sitter on what's called the so-called de Sitter effect, and Hubble did not really understand that he had found the expansion of the universe. I mean, itís quite clear if you look in detail at the proceedings of the National Academy of Sciences, Volume 15, in 1929 that the final paragraph of that discovery paper which has been taken to be the discovery of the expansion of the universe, says, in effect, it is not clear what the true nature of this relation is. It may be — now he may not have been this explicit, but the essence is —- it may be merely a tangent relation to a more general form than a linear one. Now why did he say that? He said that because de Sitter had predicted that the red shift should go as the square of the distance. In other words, a parabolic relation. Now you know that if you sample a parabola very close to the vertex and put a tangent line so that, you can get a linear relation, so what Hubble implied was we may be observing only a very small distance out and we may be getting the tangent to a more general R2 relations, and then he makes the explicit statement this may in fact be the de Sitter effect. Well, it clearly was not the de Sitter effect, and in fact in 1931 or 32 de Sitter himself said that what I had explained in 1917 and 1925, or whenever it was, is now merely only of academic interest, and one really has found the Friedmanís solutions for the expanding universe which is linear and a whole new concept had nothing to do with this strange mathematical thing that had been postulated by de Sitter.
Wright: This was contemporaneous with Einsteinís rejection of the cosmological term.
Sandage: Well, I think the coupling between the observers and the theoreticians was particularly poor in those times. I think the observers didn't really know what the theoreticians were surely saying, and the theoreticians surely didnít have any idea what the real world was like, so I think what happened was two parallel streams started and then suddenly by some really marvelous thing the two met within the observatories in 1930, some eight months after Hubble had announced the linear velocity-distance relationship, and Hubble didnít know what he had. I mean — thatís a terrible thing to say, but throughout Hubbleís whole life — and you can understand by reading his papers — he clearly wanted to sit on both sides of the fence. He clearly says ďWell, the true expansion explanation has a lot of difficulties to it, and if thereís not true expansion but some unknown law of physics then the relation should be this way, and it itís true expansion then they should be another way, and he always discussed those two possibilities and he came with the limited observations available at that time to the conclusion. It is not real expansion, is not real expansion, and as late as 1953 in his George Darwin lecture you can see both these parallel things discussed. So he did not make that jump that I think all modern youngsters, and Iím a youngster in this respect, will do. We are really radical compared to Hubble in the statement that my golly the observations themselves are the manifestation of the prediction of Friedman. The Hubble time or the Hubble constant has now been shown to be ten times less than what Hubble said. It means the universe is ten times bigger, it means that time is ten times longer, and it agrees now with the age of the evolving stars which has been understood in the last fifteen years. So it all makes a coherent picture agreeing with Friedmanís models through a singularity and a creation event. OK, Hubble would never have said that, and Baade would have said you guys are wasting your time, he said cosmology in this way is nonsense. Why did he say that? Well, he said that for what you were getting at. He didn't get any time on the hundred inch telescope because it was all taken up by Hubble and Humason, Humason getting the red shifts and Hubble getting the magnitudes, so the amount of time — dark time when the moon was down was minimal, and I think he reacted against that although Baade was a great man, But no great men are — well all great men are human. All people are human in that sense, and Hubble — or Baade to the very end, and I was his Ph.D. student, I was Baadeís Ph.D. student, said Hubbleís pristine approach to this, his one-directed approach is going to fall. What you have to do is go my way to the contents of ga1axies to understand their ages. Now he didn't say it quite that clearly either (laughter), but he was a cosmologist —, but he wanted to do a bigger picture and now what's really happened is the following: In the 1960's or late 1950's, you guys know from your reading that a second revolution took place, and that was the understanding of the evolution of the stars. I don't know if you appreciate that, but that was the thing from 1950 to 1965, or 1962, before these blessed quasars came, and quasars just changed the whole direction of the thrust in a wrong way, in really a wrong way because the theory of stellar evolution and the formation of the stars, their ageing, their age dating, the explanation of the H-R diagram was a product of 1950 to 1962.
It was centered in two different places. It was centered on the east coast with the theoreticians with Martin Schwarzchild and it was centered out here with the getting of the H-R diagrams for the old systems, and that then has merged into the Hubble approach of the galaxies and the understanding of the stellar content of the galaxies, understanding how old the galaxies are of themselves and in showing that this age of the galaxies is the same as the expansion age of the universe. So, now one can understand these two big streams as if the first book of Genesis were right. Now, when I say that — yeh, yeh, yeh —
Wright: Could I just say one word?
Sandage: Yeh. That's going to be misinterpreted by all you people that are now listening to this tape in the library (laughter) because I don't really mean it.
Wright: There's another thing that comes to mind in the late fifties — this period where you are talking about the rapid expansion of theories of stellar evolution on a larger scale looking at it on the galactic scale. Wasn't this time when there was considerable debate — continuing debate over/problem of clusters of galaxies and the difference between the so-called ďnumber mass viral theory mass of clusters? What influence is your perception of this as having had on this the development of cosmology from the point of view of stellar evolution?
Sandage: None whatsoever.
Wright: This was sort of a tangential thing off on the side?
Sandage: Yeh, there still is a problem as to why the observations give what they do, and the observations generally must be right although (laughter). We could talk all afternoon about that. You know Bondi who is a pure theoretician, has a theorem, and his theorem is a great one. He says when a theory is confronted with observations and the theory does not agree with the observation, what do you do? In the history of science you always distrust the theory, but that's not true. You must distrust the observations.
Wright: There are historians of science who I think would modify that view. As a matter of fact there's a fellow at Columbia who is now re-doing many of the classic experiments and has discovered that the claims of accuracy on previous experiments have been over estimated by an order of magnitude or so on numerous occasions.
Sandage: Well, this is known as Bondiís theorem, and when Bondiís theorem first came upon the scene in 1952 most observers, of course, thought that that was wrong. There surely is interplay between theory and observation. If somebody were to say "well, I just observed I dropped a ball, or I let loose a ball and it went up, why now in the history of Newton's law you knew that that observation had to be wrong, so that's in that sense Bondiís theorem is right in the presence of well documented theory. Well, so this business of the virial masses that youíre talking about we probably donít know the mass to light rations, we probably donít know the masses of the galaxies yet. It's a problem which is not solved, but that problem in itself is tangential to the question of the expansion of the universe, is tangential to the evolution of stars and outside the realm of age dating the clusters of galaxies themselves. So, I guess the covering for the whole story, the covering for the whole piece is really the expansion of the universe per se, and the little nitty details of how stars are formed , how galaxies are formed are fascinating, but they are just pieces of this larger picture. Well, O.K., O.K. To really understand this larger picture/as to how the world as we now see it came into being, you have to understand those details. All I'm really saying is that one whole area of this detail was not understood in 1945, is completely understood in 1965 and that has got to be the story of the first few years of the two hundred inch. The story of the hundred inch on Mt. Wilson was the discover of expansion, but I think the whole understanding of the diagram and the whole understanding of stellar evolution of age dating of the stars took place in fifteen years, and that's not generally appreciated. NOW, those two streams have merged, and astronomers are now talking about the problems of, well, what happens when you look back out in space five billion light years distance. You're seeing galaxies as they were five million years ago. What happened to their stellar content? What happened to the light? Well, you don't know that until you know something about how the stars that they contained evolve, and you couldn't do that at all in 1945, but that turns out to be the crucial question now to understand the meaning of the measurements of the red shift of elliptical galaxies of large red shift which in itself tells you something about the whole deceleration, the whole history of expansion, whether expansion is slowing down so fast it's going to stop and contraction begin or whether we only live once like the beer-ads say, "you only go around once," and so you have the Schlitz and the anti-Schlitz astronomers, and some people think no, you can go around more than once. I donít know, I have been on both sides of that fence. I think the universe is slowing down and I think the thrust of what I have tried to do with telescope has shown, I think, that there is a deceleration, but how fast a deceleration depends on stellar evolution and look back time of elliptical galaxies, and thatís an unsolved problem.
Wright: If we could try and get back to your childhood (laughter). I think it would be of interest to others if you could tell a little bit about what prompted you to have an interest in astronomy. Was it a fascination with looking out at the stars at night?
Sandage: I don't know, that's kind of like — there's no analogy. I don't know what to say. How did you become interested in books? How did you become interested in girls? How did you become interested in the world around you?
Wright: Are you saying it happened very early?
Wright: Well that's interesting too because I have talked to some others — other people and they became interested in astronomy after they had graduated from college and were seeking out something to do.
Sandage: Well, I can remember, I think, when it was quite clear that I had to be an astronomer and that was when I was in the third grade that I knew I had to be an astronomer, and how that came about I guess I don't really — cannot reconstruct but it was in Philadelphia and the Franklin Institute which is like the Museum of Science and Industry was present, and I would go down there every Saturday and would spend the whole day, and a childhood friend was also interested in astronomy had a telescope and we'd visit the Planetarium two times every Saturday and we'd see the same show twice. It was like sitting through the movies. I sat through the movies twice too. (laughter). And there was a guy by the name of James Stokely who's still alive, strange enough, — no, it's not so strange, but he's still so very-active, and he's in the Midwest. But he was the planetarium director at the Planetarium in Philadelphia. From that and from this friend who had a telescope somehow it all came together and so science was a way. I guess it came upon me somehow that science was a way to find absolute truth. How as you — as one becomes a scientist maybe science is just as on great quicksand as you historians are. It's not quite clear. Einstein said God is not capricious. Well, I think that's really true because the laws of physics are reproducible all the time when if you have an event, and you as an historian and you as an historian describe those two events you get completely different descriptions according to the way you're hooked up with the way or your view of society and the way those events have occurred in a particular time and a particular place. Well, science is not quite like that. Science is more — well, you know what I'm trying to say — more absolute, more independent of the existence of human beings if you like. The moon doesn't care what happens on the earth, Watergate and all the rest can just go on and the moon's going to tool around the earth and its distance is going to increase as the tides slow the earth down independent of any of the caprices of man, and I guess itís this absolute, absolute validity; somehow of science which is a very how to but it is a very comforting feeling. You may be alone, but you're alone in a tremendously rational world. The world of science is absolutely rational, and no matter what you think about, or what I think about, it's going to go ahead. Does that make any sense?
Wright: Yes, yes.
Sandage: So, in a sense the existence of human beings is interesting. Thatís where one gets all one's pleasure. No, no (laughter) that's not true either. Your friends are great, but mystery of it all is why itís so regular and why you can do something in a. positive way by sitting down and thinking, or by sitting down and making observations. The physicist when he throws something from his machine will get a positive answer that's the same today, yesterday, today and tomorrow — the same yesterday, today and tomorrow, and that's something.
Wright: Just for the record, you were born in Iowa and you moved to Philadelphia.
Sandage: No, moved to Oxford, Ohio, and my father was on the faculty of Miami University in Oxford, and he went for two years Ė 1936 to 37 to Philadelphia, and then we moved back to Oxford so Ė a Midwest background all the way; conservative Midwest and all that means (laughter). You guys are laughing. Why?
Wright: We're from conservative Orange County.
Sandage: Orange County? Both boys out of Orange County? (Laughter)
Wright: You guys must have moved in from some place. Whereabouts?
Unknown: New York
Wright: Well I'm a native Californian. I've spent most of my life in South San Gabriel.
Sandage: I see
Wright: I understand you live in San Gabriel —
Sandage: Well it's in the county area, just below Huntington Drive, so we're unincorporated; have no mayor or no politics to worry about. No local politics. (Laughter) Somehow, well, I guess I find science to be the most stable thing there is. It's what the universe is made like, and if you want to say well, O.K. that's — that's — well, I hate to use the word religion because everybody has a different view of religion, but it's something stable in a changing world, and especially the stuff out there in astronomy is stable, and the earth could disappear and the stars wouldn't care. (Laugh) The universe would go on expanding.
Wright: What reaction did your family have toward your interest in astronomy?
Sandage: Oh, I think they — it kept me off the streets. Oh that's a flippant answer. Astronomers are harmless in a certain sense, but also I guess I really feel astronomers are very important in the long range history of the human experience. You ask what stands out from 1600 on, and the great peaks in human thought have something to do with the uncovering of the real world. One understands Galileo. One understands Kepler. One understands Newton, and the astronomer has — or the deepest questions that anybody asks are related to astronomy somehow. But that's not why I got into it. I guess I got into it because it was the fascinating solution to almost impossible problems. Could you answer the question if your life depended on it, and somebody came up to you and said, "Look, something's going to happen to you unless you can tell me within a year what the mass of the sun is." Now, every human being before 1700 would have been killed (laughter) because nobody knew how to determine the mass of the sun, or just the distance to the moon. That's an unsolvable problem. But now we know the distance to the moon to two centimeters. How do we know that? And you can see the distance of the moon changing with time. I mean, it actually changes. That two centimeter is close enough measuring now so you can see the secular change of the moon from the earth. Well, O.K. O.K. Just given the problem you can have a tube to sight along. You have a clock which is a sand machine. You know, you know, a three minute egg machine, but it was bigger than three minute eggs in 1600. And you have a way to measure angles. Can you tell me the distance to the moon? Not only in 1600, but that problem was solved in principle by Archimedes, and that solution is beautiful, just beautiful. Have you ever read the story?
Wright: Sand Reconer (?).
Sandage: Almost, almost. But that isnít what I was going to say. I was going to say have you ever read the short story by Aldous Huxley called ďThe Young Archimedes?Ē
Wright: No, I have not.
Sandage: O.K. There's a little boy six years old whoís found on the sand in some Mediterranean spa — watering place in 1920, drawing a right triangle and saying "Ha, the square of an hypotenuse is equal to the square of the sum of the sides, and he rediscovered for himself six years old, what Pythagoras did, and it goes through the whole business of what his thought was, and it shows how his life was destroyed by not understanding in a sensitive way what that little boy was doing — by his parents not understanding in a sensitive way. Well, that's really, really how nature grabs some people, and that's how it grabbed Pythagoras, and that's how it grabbed Archimedes and how it grabs all astronomers, because astronomy is the science of the impossible. You just can't do these things. The only link you've got with the universe is of light and from that beam of light you can find out everything. You can find out when formed, you can find the temperature of the stars, you can find the diameters of all the stars. That's miraculous, just miraculous. Youíre going to change from being historians (laughter) of science and understanding how from binary stars you can find the mass, the diameters and all the rest. So I think thatís what drives people, the beauty of what theyíre doing, the interest in solving problems. Well, weíre diverging.
Wright: Itís an interesting diversion.
Sandage: Well, anyway, I think you won't talk to any scientist, that is not excited in doing something new, not because necessarily it's new, that's certainly isn't — and what his colleagues think. That's really not the reason that drives most people. It's a curiosity. It's a tremendous curiosity to wrench from nature what you didn't know before, and the rest just dissolves, somehow, just disappears. It's gotta be this curiosity, you've got to like what you're doing, and I think all scientists like what they're doing.
Wright: According to the record, you went to Miami University for your undergraduate work. What were your impressions of some of your courses?
Sandage: Well, I was completely ill prepared. This was during the second world war and I didn't graduate from high school. I never was a senior in high school. I never had a physics course in my life. So I took physics at Miami University and it was the toughest thing I'd ever done, until the next course in physics which was at Miami, which is the toughest thing I ever did until the next course in physics which was at Cal Tech, which was beyond belief difficult. So, I was at Miami for two years, and in those two years learned something about the way you've got to act to do science. Now how do you act? You've got to solve the problems. You've got to do something to solve the problems. I didn't have a clue the first three months what to do to understand to solve those problems. I had a very understanding professor who was the greatest man in the world — but two or three. I mean he was amongst the two or three people in the world. His name was Ray Edwards and he nurtured about a hundred and fifty people through their Ph.D. finally in physics and through a whole series of — well, the students were frightened of him at first because his standards were so high. He never gave any sympathy — well he gave a lot of sympathy, but he expected you to really to work very hard, and the feeling what the nature of science is in rigor and self- discipline came through to all the students exceedingly well, and he was a great man. So there at Miami University Edwards did that and the head of the Mathematics department did that. He was the astronomer. Well, it was just a great experience.
Wright: So you did take some astronomy courses at Miami.
Sandage: No, I never had an astronomy course in my life until I came to graduate school at Cal Tech. I mean, one knew the astronomy. You just knew the astronomy and I think anybody who wants to be need not take astronomy courses. It you're really going to be successful at astronomy, you just know it. So one knows the difference between sidereal time, synodic time, mean solar time, and all the seven motions, or how many there are, so it is just part of you. Feynman. You ought to interview Feynman. He says, you got to train yourself to think like an electron, if you can think like an electron, you can go through all those slits. So, I never graduated from Miami. I went into the navy during the War and came back and went to Illinois, and there you understood what it meant to be a professional. Miami was a small liberal arts college and Illinois was a big place where there were a hundred and fifty undergraduate majors in physics, you know, and either you made the grade or you didn't. I went in when I was a junior and told Professor Becker "I can't solve your problems in mechanics. What do I do?Ē He said "You think. You sit down and you think." And so I tried that and finally it seemed to work a little bit, but — well, it was hard, somehow, and I did get through. I got through O.K. and got a letter of recommendation to Cal Tech by the head of the physics department and was among the first to come out to Cal Tech in astronomy.
Wright: So you got your bachelorís degree in physics?
Sandage: In physics. That's right.
Wright: This is really not on the subject of astronomy, but could you tell us a little about the social and political climate of Miami University?
Sandage: Oh you know that was in 1946. That was before you were born. (laughter) Social and political climate. I think that the folding time for the change of social institutions is now like five years, and I think that I was raised at the end of what might be called the second Victorian era. You know what that means if you're almost as old as I am. That means that when you went to the university teachers were not only supposed to teach, but they were babysitters. You know, the girls had to be in at 8:00 o'clock at night, and it was a whole new world, a whole different world. Rather it was an old, old world, but different, so I don't know what you mean by social climate. It was a climate where dissent was unthinkable. I mean I never would have thought of doing anything that my teachers said I couldn't do, somehow, so conformity was really a strong word. It was just like home in those days. You never talked back to your parents. I never talked back to my parents.
Wright: Did the atmosphere change to Illinois. You said this was when you first made contact with professionalism as opposed to the other —
Sandage: I guess I didn't really mean that. Miami was a great place also for students. I guess I was always interested in what Lawrence Kubis said and Ann Row about the making of a scientist, and I was interested in the making of a scientist in the way that it pertained to my own history. I think that itís true, that many scientists are shy, that many scientists are more at home with ideas than with people. Not thatís not quite — thatís surely not true of a lot of people. I mean for every one like that you probably have one or two of the opposite. Lawrence, from what I understand, was very good with people, and what drove him was different than what drove Oppenheimer. I guess Iíd say I was shy. I guess I say I still am, and I think that Iím more at ease with the impersonal things of the universe than I am with people. That's changed in the last ten years a great deal from what it was as an undergraduate, but I felt comfortable, somehow, in the positive world of equations where you knew. You had a test whether you were right or whether you were wrong. It'd better be. The world of social science — I don't believe that's science. I believe it's a world of opinion. Now that doesn't mean that's it's not fascinating to read the thoughts of opinionated people in past times of the whole history of social change is made by opinionated people, by Voltaire, by Burke, by all these people, and that's a very strong thing in
the way societies go, but it has nothing to do whatsoever with the development of science in the renaissance period. It may have something to do with the way science is funded now. Science has changed a lot now since the war, and guys like Lawrence were successful for two reasons. One that they were good scientists but one, that they were really good salesmen as well. They couldn't be shy. O. K., you asked what it was like at Illinois or at Miami. I think most people in the physics options Ė the hard science options were shyer — were not the social types on the campus, but I think that's true today as well. If you look at Cal Tech and the type of people at Cal tech you have some social activists. The head of the student body was a really good physicist, Joe Rhodes, five years ago, and he became a radical element — went through Cal Tech however. You canít stereotype people. I was more at ease with books than with people. That was not what you were asking exactly.
Wright: I was just wondering what you did when you were in the Navy.
Sandage: I went to school and was an electronics technician, and could repair radar and knew all about vacuum tubes, and all that good sort of stuff.
Wright: That sort of strikes a ring — has a similar ring because that was exactly the same thing I did.
Sandage: Where'd you go?
Wright: I was on an ocean-going mine sweeper repairing the radar which never worked. (laughter)
Sandage: Where'd you go? It worked after you got on the mine sweeper.Where'd you go to school?
Wright: Well, that was actually after I went to school. I was in the Naval Reserve and went on active duty.
Sandage: Oh I see. You didn't go through the Navy program.
Wright: No, no. Actually I got training in electronics at a Naval Reserve unit in Pasadena.
Sandage: Oh my heavens. On Green Street.
Wright: No, it's on Paloma.
Sandage: Yes, yes, yes. Out near Sierra Madre.
Wright: Right beside Victory Park.
Sandage: Thatís right. How about that? Very good. (laughter) Well, things change because you knew about transistors when you were in.
Wright: No, it was all vacuum tubes.
Sandage: Was it? Well good. You and I could get along because I only understand vacuum tubes theory. O.K. Well, and then I grew to hate electronics, so I came out of the Navy with a vast knowledge of electronics which I will not apply unless it's absolutely necessary (laughter)in all that I do, and it really is quite necessary, you know. So that is the frustrating part of astronomy, doing electronics. (laugh)
Wright: It has helped you out in your subsequent work, though.
Sandage: Oh sure. Sure, I mean all the measurements of the faint galaxies are photo-electric measurements. I haven't designed or built the equipment. I think probably I could if I put my mind to it, but just don't like it (laughter). Oh dear.
Wright: When would you say you really made your decision you wanted to be an astronomer?
Sandage: When I was eight years old.
Wright: It really was?
Sandage: Of course. (laughter) No, no. That's a true statement. I knew I had to be a scientist somehow. I don't know why I knew it or how I came to know it, but I was just oriented that way forever, just forever and my old man told me "You know you go this way and you'll burn yourself out when you're thirty. It happened when I was (laughter) thirty-five, forty, forty-five, but we're still going (laughter). Oh dear you want to come back some other time and finish this?
Wright: Really did your family actually support you — your aspirations, or was it on your own?
Sandage: Oh, I think they asked whether that was really the right thing to do. Nobody had ever seen an astronomer around Oxford, Ohio, but they were neutral I guess you'd say. No, not really neutral — they were encouraging — they were not discouraging, and they let me have rather complete freedom at Miami University.
Wright: You said your father was a professor at Miami University.
Wright: What was his field?
Sandage: He taught in the business school, so science was a little bit foreign to his thinking, but he had a tremendous amount of self-discipline. Somehow that feeling of self-discipline came over to me as a child, and it came over to me by picking the dandelions out of the lawn, and Saturday work and all kinds of tasks and chores that had to be done for the family, and I guess I developed a work ethic very quickly which I think is important. I guess I'm trying to teach my boys that too, and it's really very hard in this modern age to do that, —
Wright: With all the other interruptions.
Sandage: Not the interruptions, but the feeling I guess of maybe you don't have to work very hard. No, I don't know. I don't think many people believe that they are captain of their own soul and masters of their own fate, and that came to me very early and whatever happens to me is my own business. I can make it happen, and it won't just come. So that feeling of self-discipline somehow was engendered in me by my father, and it was engendered in me I guess because he had to work very hard. He was raised on an Iowa farm where you had to walk to school and you had to take — hitch up the horses And go down mud roads and so on an so forth. No electricity. Stuff that most people don't understand anymore. You know this country is really extremely young. I can remember going to my grandfather's farm in Iowa without any electricity, without any running water inside. A cistern and a pump. Now that was only thirty years ago, or forty years ago, but you tell a young person that and they can't imagine being alive before television was invented. So the work ethic and the self-discipline is something that doesn't come naturally any more. I guess it called to me from the day I was born. Environment, not from genetics (laughter).
Wright: Well, at Cal Tech in the curriculum that you were in, you must have had some professors that impressed you. Could you relate some anecdotes?
Sandage: They all did, because they could all solve all the problems, and that's not a joking matter. I had a terribly hard time at Cal Tech because there were a lot of people that could solve all the problems. I think two things at Cal Tech. Cal Tech was the most difficult experience I've ever gone through, but it was also the most exciting experience because, somehow every single day you could see the inter-relations of mathematics, physics, chemistry and little flashes of lightning or great thunder claps of understanding would come every day. It was tremendously exciting. It wasn't just to get through. It was the way the world was put together. I can't describe it — it was a mystical experience, but also an exceedingly difficult experience, and I guess the five years I spent there I'll never forget, as long as I live, but I can't remember anything about it. (laugh) Those two may not make any sense put together, but it was beyond belief an experience.
Wright: Do you recall any anecdotes about some of your lab work?
Sandage: I said I can't remember anything about it. (laughter) Well, everybody was a character. Everybody was a person bigger than life, and of course he was bigger than life for all the students. Now, I think the greatest shock was the day I arrived when a man was cleaning out his office who'd just gotten a Ph.D. and he was a student of Tolman. Now Tolman was a very important character in the whole history of cosmology. He was the one theoretician that understood, from 1928 to 1935, what Hubble had done and what the significance of it all was. So he was a very important man on the campus in a lot of ways. He was professor of theoretical physics and his student — well he'd just died three months before I got there — and this student was cleaning out his office and he said ďAh-hah, youíre a new astronomy student, huh?Ē And so, he took me in and then he started to tell me how hard Cal Tech was going to be and at the end of what he said it was impossible for anybody but that man himself to have gotten through — to listen to what he had to say. But he was right. He was absolutely correct; so that was the beginning and it never let up from that time until the Ph.D. five years later, but I guess the highlights were being able as a student to go up and observe with the two hundred inch telescope for Hubble within nine months of it going into operation — the worldís biggest telescope, the hope for astronomy that had been in everybodyís mind since 1930, and to be able as a student — second year graduate student — to go up and actually make the observations so the first observations were made by me — that is my first observation on the telescope was in November, 1950. Letís see — and, that was I guess one year during the time that the telescope had been in operation, 1949 — maybe it was in April, 1950.
Wright: I guess it was dedicated in 1948.
Sandage: No it was dedicated in November — oh, I don't know when the dedication was.
Wright: I mean the public dedication.
Sandage: That's right, but first routine observations were made in November, 1949, and I — oh, no, this was not that early. I went up in September 25, 1951. Now that was not long after it went into operation — that was eighteen months after it went into operation, and then I've been up there ever since. So that opportunity to use that telescope, to see what the universe is like I guess was the greatest experience Ė almost, the greatest I've ever had — almost the greatest experience, but what I think was the greatest experience were the times later when results came out that you either expected or didn't expect with that telescope from a long series of speculations or observations which led to same ideas.
Wright: Well, prior to Baadeís work on the Population II stars, the Hubble constant was in conflict with certain geological data. Do you recall any of your professors perceptions of this time scale paradox?
Sandage: No, that was really never discussed. What happened in the early days at Cal Tech was the astronomers were essentially physicists. There was essentially no cosmology taught. Well, there was no cosmology taught at all, and it's really [???] youíre questionís very interesting because the Hubble constant itself by Hubble in 1935 — Baade never said that he changed the scale of the universe. What Baade said was only that he changed the distance to the Andromeda Nebula by changing the zero point period-luminosity relationship by a magnitude and a half. Now itís all these guys in the public press office that started this business of saying, ďWell, you change the distant to the Andromeda nebula by a factor of two. That changes the whole universe by a factor of two.Ē Well thatís nonsense, absolute nonsense, and subsequently it has been shown that there were progressive errors in all the other steps out beyond the Local Group where you really get the true expansion so that what we now say is the Hubble constant is ten times less — not two, — but ten times less. That has nothing to say whether Baade was right or wrong. Baade was absolutely right in changing the distance to the Andromeda but that has nothing to do with the rate of expansion of the universe. So that's how it came into the public press somehow that the distance to the Andromeda nebula had changed the whole structure of the universe and it just isn't so. It just isn't so. So, what really was the case in 1952 — before 1952 — was that the Hubble age was about two billion years. That was shorter than the age of the crust of the earth even when the scale of the universe was changed to factor of three and only got up to six billion years, but then the age of the oldest stars got up to thirteen billion years, so there was still a discrepancy. So what the current situation is, is that the Hubble constant is now ten times what Hubble said it was. Instead of 1.8 billion it's 18 billion. The age of the oldest stars is thirteen billion. There's no conflict whatsoever. In fact the ratio of those gives the slowing down rate of the universe. You can tell it's not slowing down fast enough to come to a halt, and it's only happened once. But none of that was known in '52. So you say what climate was in '52 at Cal Tech. That cosmology was something that was just not discussed very much. It was the concern of Greenstein who was the first chairman of the department and the only astronomer there in the first four years, was to tell the students about stellar atmospheres, how to interpret spectral lines in the spectra of stars, something about stellar interiors, how the stars evolved — not evolved, that hadn't been understood at that time, but at least the stellar interiors and something about interstellar matter, so the whole field of cosmology was not a subject until maybe ten years ago. Hubble was the only one working in cosmology until about ten years ago. Well, Hubble died in 1953 but it's become a modern subject only quite recently. It's not quite true what I say because the steady state theory care — when was it —
Sandage: '48? Yes, what I say isn't quite true, but it hadn't grasped — it hadn't become the dominant field of astronomy that it has now. It was the H-R diagram and stellar evolution.
Wright: There must have been some reaction to Baade's work among the graduate students and some of the professors.
Sandage: Well I think they all understood that it meant really the change in the calibration of the distances and the distance to M31, so yes, it was understood what had happened and there was some excitement but that didnít change ll the professors and all the students to go in one direction. Most of the theses, if you look at the subjects at Cal Tech in those early days were not connected with cosmology. Almost all the work in the physics department which was centered on Fowler connected with high energy astrophysics, was centered again about questions of stellar evolution. I mean how did the nuclear reactions go, what were the reaction rates or the carbon cycle to proceed, so the whole of the work in Kellogg Radiation Lab was concerned with stellar evolution. So, as I say, that era really was the time when stellar evolution was predominant, and it was the discovery of quasars which led the whole pack off in another direction, unfortunately.
Wright: Well, the red shift was a key to, in Hubbleís work, and Zwicky had contrary views to this —. Do you know of any personal animosity between Zwicky and Hubble as the result of this?
Sandage: Hubble was really rather withdrawn from personal conflict. He was really above that. I think that the personal conflicts, or disagreements in questions of priority were not serious ones at that time. Hubble had a very universal view of things. I don't think Zwicky bothered him at all. Zwicky bothered Baade very much and van Maanen bothered Hubble in the early days, but I think that really everyone discounted Zwicky on the campus for many, many years. You come back to Zwicky often, but I think he was a rather minor influence, either positive or negative. He did what he did, and had his views about priority and had his views about the way the world went, but he was almost alone, so that the great thrust of the work was he was not in the main stream of the way the other astronomers were thrusting. Now that's not quite true of the last five years of his life where a lot of other subjects were coming up that Zwicky had made comments about.
Wright: Pygmy stars?
Sandage: No, I think the pygmies never became — that is, I believe there are no such things as pygmies, and the question of scientific proof comes in and what is taken as proof, what is a passing beautiful experiment, what is speculation comes in. Astronomy is very hard because you can't touch the things — work with, but I think that Fritz Zwicky was more of an interesting person to the outside people than an influence in the way that the work went here. Now that's not — it may be a prejudiced view. You know that he and I didn't get on very well, but —
Wright: I wasn't aware of that.
Sandage: Well, I really believe that he did not have the self-discipline himself to plug all the holes. It's terribly easy to talk and terribly difficult to get something right, and I think he just would not work hard enough to plug all of the different routes that he'd opened up. I mean that he said were passible. Now he said almost everything about everything, so some of the things had to be correct, but the style of the way somebody does something characterizes that person. Zwicky's style was completely different that Baade's style, completely different than Hubble's style and clearly different than classical people in history of science, like Rieman and all the other people he mentioned. And sometimes those people are successful, but very, very rarely. I think if you were to put Tycho on a modern stage, he would be like Zwicky in his demeanor and his feeling toward other people. Actually there was a very successful man. Now maybe Zwicky was successful also, but it just happened that Zwicky was not in — historically — in the stream that had very much to do with the work or the thrust from 1930 to 1965. That is my viewpoint.
Wright: Do you have some reminiscences of Baade?
Sandage: Oh a lot of them, yeh. (laughter) He was a very interesting man, and he had tremendous numbers of stories about all kinds of people, and he loved to joke about people. He was the only one that observed with coat and tie in the mountain — on the mountain. A lot of people did in the early days, but he overlapped the young people and he didn't understand the slovenly attitudes on the mountain. He could tell stories about everybody and everything and there was always a grain of truth but he always manufactured or increased the story of course for the impact, and it was largely jokes on him and jokes on his friends. He would never talk about his enemies, and I think he was liked by a tremendous number of people. He and Zwicky didn't like each other at all, but he was — he never took citizenship. He was a German citizen. You know during the war with the blackout in Los Angeles he had a lot of time on the hundred inch. That's when he resolved M3l — he was a supremely good observer. He never — he published very little, but he always had a hypothesis about what he was doing and that way of thinking, I think, permeated the first two or three years of the graduate school at Cal Tech because many students came up and talked with him, and many students overlapped with him on the mountain, so he was a great influence in that way, but he never formally taught. But he would tell you all about astronomy for hours at a time. I think what the ideas of stellar evolution which came from a number of people, talking like this — he had some, Schwarzchild had some, the observations were made by others — the interpretation by others, and Baade's Population concept was crucial to this whole thing and again he didn't quite understand what he had in terms of age dating and the various generations of stars at first. That developed. But he was certain that there were two different types of objects, but that came as early as '38 when Hubble and he collaborated on the only paper they ever collaborated on and that's the dwarf galaxies, Scultur and Fornax where they — where the hundred inch went way down to the South — minus 38į — and photographed what had been discovered by Shapley, the first dwarfs spheroidal galaxies in the local group, and they could actually resolve in the stars what later became what Baade did resolve in M3l much more distant, and he then did not make the correspondence because there were globular clusters also imbedded in the envelope of these dwarf galaxies, and the global cluster stars resolved at the same level as the atmospheric stars in these two galaxies. And right there he should have snapped — his mind should have snapped open and said "By golly, we know the form of the H-R diagram." Well it didn't really come until almost after the war, that correspondence. He had resolved M31 in 1941 but the understanding of that didn't come until later, and it really came about the same time that the calculations were made of the lower part of main sequence and the mapping of stars off to the right. Those two ideas melded together and then it was quite clear that what Baade had found was an age differential. The oldest stars created in our galaxy compared with the young stars that are being formed all the time. So this interpretation in terms of ages was not immediately done by Baade but the whole of the population concept was the beginning of that stellar evolution.
I guess I would say to you that the thing I'm proudest of in what I've done is some connection with that business of stellar evolution, and that came about because I was not only Baade's student but I was Schwarzchild's student in Princeton for six months in between the time that I was doing my thesis. I broke and I went to Princeton and it was that time that I understood from him what the nature of the mapping of the stars on the main sequence was, and for fifteen years after that the only subject I ever worked in was stellar evolution, and you don't know that. Most people don't know that, but half of the total number of papers I have written are on this business of the evolution of the stars and I consider that to be a much more solid piece of work than the cosmology. Cosmology is just beginning I think, and I would hope one to the same state that stellar evolution is now, but it's really just now beginning, and the public feels that cosmology is more important for somehow it's thought that I work in cosmology, but thatís not true. Iím a stellar evolutionist. Does that surprise you?
Wright: Well not exactly. But I guess — I have read a few popular articles about it and they muddied the waters a bit.
Sandage: Popular articles don't mean anything. I mean that's what the writer that wrote those has thought, I don't mean that exactly.
Wright: I know you've given a few comments about Hubble, but would you care to give some additional reminiscences about him?
Sandage: Well, he was a very difficult man to know. I think he was — I only knew him at that very late — at the very last of his life. I met him first in 1950. He wrote this marvelous book called "The Realm of the NebulaeĒ in 1936. I read that when I was a little boy and thought I had to work in that field somehow, and I think it was the case that most people at Cal Tech were kind of frightened that he would come up here. There was a division then as there is now between this place and Cal Tech, and Hubble stayed up here. Greenstein had some contact with Hubble, but not very much. Fowler had some contact with Hubble, but not very much. He was a great god that was sitting at Santa Barbara Street, and he was a great god. He was the greatest astronomer since Newton. That's come in retrospect. It wasn't clear at all at that time. A prophet in his own country is without honor. Hubble really was without honor, in those days. Nobody really understood the importance of what heíd done, or not many people had. So, I guess that summer that I met him, he outlined what I was to do and I did it, and in August I was sitting in the basement of this building — of 1950, August of 1950 — and I was asking Minkowski when Hubble was coming back, and at that moment a phone call — the phone rang in the basement and Minkowski answered the phone and he came back and said "He may never come back because heíd just that moment had this massive heart attack. So I only knew him for maybe two months or three months before he went in the hospital for about a year and then he was OK for two years after that. It was that period that I got to know him really very well, and I think we became good friends as much as a sixty-two year old person and twenty-three shy person could do. I think that by that time my idea of what was crucial in science about clarity, about rigor, about lack of speculation, about it's useless to try to impress other people — you've got to impress nature — I donít mean it exactly that way, but it doesnít matter in debates who is right or wrong because natureís always right, and you just have to wait and get more observations or more data, and all these controversies are crazy, just crazy because the advance of science is going to change that. Well, I had those ideas already formulated by that time, so we were both very conservative I guess you would have to say, even at that time. Iím not conservative — Iím very conservative in science, and I still am, and I dislike those people that donít go out and try to prove what they say somehow, and I — thatís the rigor of the Riemann approach or the Faraday or the Hardy approach in pure mathematics, but I guess Hubble and I got along. I donít think Hubble would have gotten along with people now like Carl Sagan. He may be a very good astronomer but he speculates all the time for example. So, I guess — well, he was a very impressive man, a very impressive man. A very withdrawn man. I mean youíd never joke with him. Youíd go in and it was like talking with God. Well, Iíve never talked with God (laughter) donít know really how it would be. Make any sense?
Sandage: All right. Whereas Baade was completely different. I mean youíd go in to Baade, and heíd tell you a million jokes and a million stories, and — about people. He was just interested in people, and Hubble wasn't interested in people. No, that's not true either.
Wright: I understand that he did give a number of public lectures and things like that.
Sandage: Yes, yes. But — how to say it? I can't say it exactly. He would give a public lecture which would be all the difference between — no, I can't mention any names, but, yeh — you just wouldnít. Well, you'd go to be educated instead of be amused.
Wright: Could I interject one thing here? One or the things on these tapes is that you can reserve and have them not made public for a stipulated length of time, you know, so if you —
Sandage: Oh, sixty years.
Unknown: Yeh, if there's something on the tape —
Sandage: (laughter) The whole thing! (laughter)
Unknown: Well hopefully not quite that extreme.
Sandage: Yeh, yeh, O.K., O.K.
Unknown: So it is confidential. Those parts which you might like to keep confidential can be kept confidential for any length of time you stipulate.
Sandage: Yeh, O.K. Well, I appreciate that, but I guess I'd say that Hubble was an impressive man, and Baade was an amusing man. Well, that doesn't mean anything. I have visions in my mind what these two guys are and I'm sure it doesn't come over, but you'd like to be with Baade to drink beer and you'd like to be with Hubble in the presence of God. So those two donít normally occur at the same time. (laugh) That's the only way I can put it.
Wright: Would this account, perhaps, to some extent for the fact that Baade and Hubble did not interact very much?
Sandage: I think their styles were different. Yes, their styles really were different, so — I think that they respected each other, but they wouldn't go in and talk with each other of an afternoon. I think everybody's style's different and I guess — I guess there's no really right style. No, no — I don't believe that, but most people believe thereís no really right style. The only right style for me is rigor, Riemann, and Einstein. The rigor like those guys had, like a pure mathematician. Baade was much more intuitive and Hubble was — well, Hubble was very strange. Hubble was very intuitive also and he could get the correct answers off the lousiest plates. Baade's plates were superb, mostly unmeasured, and so their styles were different and they were both great astronomers.
Unknown: So during the 50's and 60's you worked principally in stellar evolution.
Sandage: Oh yes, that's right. My thesis was "The Main Sequence of Globular Clusters," and with the two hundred inch one got very faint magnitudes, got to the turn-off point, and the turn-off point in globular clusters was found before the explanation was found, so I showed Baade and Schwarzchild the diagrams of M-3 where the — this is the halo globular cluster M-3 — where the turn-off was made, and I was then about two weeks later invited back to Princeton to work with Schwarzchild who was following up ideas of Chandrasekar and Schoenberg on the evolution of the star after it reached a crucial phase when it burned five and ten percent of its helium and Schwarzchild was remarkable. I worked there as his assistant, but I didn't assist him. He didn't need any assistance at all. So I learned from him for five months, and out of that came my first and only theoretical — deeply theoretical session of my life in school, in a sense of being connected with a pure theoretician, and out of that flowed all of the ideas of the mapping off the main sequence, and then I came back here and applied those ideas to nature, to the explanation of the galactic clusters, and put them in a sequence where the turn-off points are shown graphically, and that's the thing that's shown in all the text books. Well, that was the product first of my thesis; second of the insights of Schwarzchild and the tremendous, wonderful father instinct of Schwarzchild with a green young guy who didn't know how to integrate differential equations or anything else numerically and from that came twenty years of work. So, I looked upon four or five guys as very important, and Schwarzchild is certainly one of the very important influences, as is Greenstein, as is Hubble, as is Baade, as is this guy at Miami, this first physics teacher at Miami.
Wright: Well, I would like to try and get at some of the perceptions of your professors in regard to several different points, and I was just wondering, prior to the optical identification of Taurus ďAĒ with the Crab Nebula, do you recall any of your perceptions of your professors in regard to the distances to these radio sources?
Sandage: Well, Cal Tech was a very isolated place astronomically at that time. Almost all their research was being done here, and the interaction between the research astronomers and the students and the one professor — only one professor down here — and that was Jesse Greenstein — was almost nil. The interaction between the campus and here was almost nil, so when the attempts to make the radio identifications — the optical identifications of radio sources was going on, the students were really out of it. Us students were so terribly busy just trying to pass the courses, and research was something you did, maybe, sometime in the far distant future. And if you saw some guy who was doing research, well, you never talked with him because he was too busy doing things, so there was not very much of a group atmosphere, at least with the students at that time. Now it's changed, but we were the first group of graduate students. By, we,
I mean there was Helmut Apt, who is now the editor of The Astrophysical Journal, there's Morton Roberts who is now one of the chief radio astronomers at Greenbank, there was some people in physics that later became astronomers, and one or two people now that are not around anymore of the first year people. Greenstein was the only one down there in Robinson Hall. He taught every course there was, and he didn't have time to do — to couple up here and see what was going on in radio astronomy. So, when those things came we learned about it by reading the journals like everybody else (laughter) Isn't that awful? So, it may seem like a tremendous break through — well, wasn't the Crab nebulae identified elsewhere but here? I think the Crab nebula was identified by Bolton and Standly and Slee the first three or four that were identified, and maybe M87 was another Virgo ďAĒ was another early one but the real optical identification of radio sources didn't begin until the radio astronomers got much better positions and this paper by Baade and Minkowski formed the watershed of the early attempts, and then there was hardly anything for five years after that, and then everything started to flood after that when radio astronomers got better positions, so we were out of all of that down at the Institute.
Wright: So there really wasnít any interaction at all — or, you really have no perceptions at all of what your — what Jesse Greensteinís perceptions — or what was happening here at the Hale Observatories and what was happening at Cal Tech?
Sandage: No. The only way I knew was by being a summer assistant up here and then listening to Hubble about his visions as to what the two hundred inch would have to do in cosmology. But it was interesting because when I would bring plates down as a graduate student after observing for Hubble, I'd of course go to my office at Cal Tech, as a graduate student, and what would happen would be that Greenstein would come in, and all the other graduate students would come in and look at the plates of these marvelous galaxies before I'd bring them up and turn them over to Hubble.
Unknown: What was Hubble's vision of what the two hundred inch would have to do in its later years?
Sandage: Well he wrote an outline for the first twenty years of work in extra-galactic research with the two hundred inch, and at that time the distance scale was being changed to Andromeda, by Baade, and Hubble just couldnít stand this. I mean he just was very upset about it and was trying to find arguments why and where those distances were wrong, and I wrote one and only paper with Hubble. I'm very proud that I did write something with Hubble, and it was about variable stars, and there I put in two sets of numbers; one on the old — his old distances to M31, and one on Baadeís, and it was only because of the way that paper was worded, and I wrote the paper, that Hubble accepted it as if this were not certain. Yet a lot of work had to be done. The reason that I bring that up in my mind that shows what the flux or the state, of things — the flux of ideas in early 1953, because that's when this paper was written. Hubble — did not believe any of the distance changes. Baade had just begun to announce the results and they were not commonly accepted. But that was all an internal situation here and this was the fountainhead. This was the Godhead for all of that astronomy, this building that you're in, and Cal Tech had no tradition whatsoever in astronomy at that time because they never had an astronomy department. They were primarily a small physics school or science school and suddenly they had thrust upon them the two hundred inch telescope. Well, all of the experience in astronomy was here and the reason they had it was because Rockefeller would not give his money to a Carnegie institution, and that's true. So the only way that the Mt. Wilson people who got the two hundred inch concept — Hale was Mt. Wilson — could do the two hundred inch was to have that gift be given to a neutral intermediate party, and that was Cal Tech. So, all this time on the construction of the two hundred inch, the plans were all done here, the machine shop was at Cal Tech, the building was at Cal Tech, engineers sat at Cal Tech, the astronomers sat here and then only when it was just about ready to go into operation did they bring Greenstein out in Sept., 1948 the first astronomy department started in 1948. The two hundred inch went into operation in November,
1949 and since then he's built that place into the best school for astronomy in the world, and we're now two groups; a very strong group down here. Hubble, Brade, Minkowski had died —
Unknown: But Hubble's idea was that the 200 inch should be used to vindicate his work.
Sandage: No, no. No, no, no. Not to vindicate but he always said that his work was a reconnaissance, and to really do the very difficult very jobs precise photometry detailed work in the galaxies, to calibrate the indicators, and to get the real distance scale. So he outlined, really, how to do more than just the pioneering, pushing of the barriers aside, so when I say he was upset, I don't really mean that. He realized that it had to be changed, but he was — sorry he didn't do it.
Wright: Getting back to your paper on the original — I guess your thesis on the open and globular clusters and the turn off from the H-R diagram from the main sequence. Could you comment on the importance of astronomy in general and cosmology in particular for this work.
Sandage: (laughter) Well I think I've done that already. (laughter) No, what I really mean by that — what the impact of your question is, I guess is — did that have anything to do at all with the understanding of stellar evolution. Well I guess turn-off of the main sequence was Chandrasekhar and Schoenberg predicted, and what Schwarzchild predicted, so it was the opening up of the detailed way in which to age date. Now, one had to have the theory of how much mass was burned, so you had to — one had to do a stellar interior calculation. That's what Schwarzchild did; that's what Chandrasekhar had done before.
The actual quantitative age dating of the stars depends on where that turn-off comes, and that could only come from observation. So the observations, I think, I was involved in it some way, and the theory Schwarzchild was involved, was the father of, and a combination of those gave the first age dating of the globular clusters, and to me that seemed important because it was then the comparison of that with that Hubble time which said something about not only our galaxy but the whole universe — when the whole universe began. And it's that comparison which has driven for twenty-three years the trying to get better numbers. Ages of the oldest stars and the Hubble constant, and thatís all Iíve done in twenty-five years. Just really try to get those two numbers better. So whether it had anything to do with astronomy, it changed my life in some fundamental way.
Wright: Your work — your original work on M-100 and some of Arpís work on the Small Magellanic cloud came up with a correction of 2.3 magnitudes on the Hubble distance module for the galaxy of the Local Group.
Now this data resulted in a revision of the Hubble constant to seventy-five kilometers per second per megaparsec.
Sandage: That was a guess.
In 1958 all that was done there was try to correct Hubble's input parameters without making any new observations, so that seventy five which has gone into the literature as a constant — you know as a real value — was just a guess, and you read that 1958 paper, and it says that there's no new data going in here. It's just an attempt to correct the input parameters, and only, only right now have we finished making the new observations, and by we, I mean the Swiss guy whoís been associated with this problem now for six years, and myself in trying to relate all of the stuff from the two hundred inch from 1950 have now gone through a series of eight steps, and it's taken us about nine years to do that, and six papers have been written, and none of them have come out yet. But the Hubble constant now is based on new data, not the correction of old data in the literature but on new data, and that stuff hasn't come out yet. And that's a factor of ten. That's five magnitudes — five magnitudes is a factor of a hundred in luminosity which in distance then means a factor of ten.
Wright: Well, according to some reading I did, you're credited with Thomas Matthews of isolation of quasi-stellar objects. Can you relate how you came to seek optical identification of these?
Sandage: Yeh. That was the end of the watershed, [???], a period from Baade-Minkowskiís paper in 1955 or '56 where they did all that they could possibly do on optical identifications, then they were very unsuccessful except for a few cases, and it was quite frustrating. Things then happened in the radio astronomy so that uncertainties of three or four degrees on the sky, uncertainties came down to something like ten minutes of are, and at that very interesting moment of convolution — confluence, confluence of optical astronomers and radio astronomers, other astronomers wanting to know what they were — well, everybody wanted to know what they were — but radio astronomers coming up with positions, that a cooperative effort was made to try to identify again — start again, anew the whole question of optical identification, and so Matthews picked out a list of objects that was known from interferometry to have small angular diameter, and gave — and obtained the positions at Owens Valley Radio Observatory, which had just begun, and I went through that list and started to take photographs, and there were some galaxies which were identified, but lo and behold 3-C-48 was the best case, and I remember that case extremely well because Tom said — well, in September I got the plates and turned them over to Tom and he said in the middle of September — Well, there's something very strange here. There's only one object in that box and it's obviously a star, so I went up in October to the two hundred inch and got spectra — no I got photometry first, and it had colors like nothing else, and I got spectra the next night and took the photometry and put the spectrogram on, and the spectra like nothing else, and we didn't know what it was. This was 1960. In the meantime we found three others so we had the first four identifications of quasars and we waited three years first before publishing it and saying we didn't understand the red shift and the spectrum and so we thought they were stars in our own galaxy, but for three years, 1960 to í63, those four object sat isolated by themselves and it was Maarten Schmidt then came with the brightest so, in a sense we did isolate them, but we didn't find their nature really. Their absolutely peculiar nature was found only in '63, and I was not involved in any way. That's not quite true. I took the direct plate upon which Maarten Schmidt identified 3C273 but I've said several times that I think thatís a diversion — quasars were a diversion because it prevented one from going straight on the Hubble constant and the ages of the stars and the globular cluster problem. But, I now think, I guess, that the quasars are the means by which we can see the edge of the world, and what do I mean by that? I mean quasars you cannot find red shifts greater than about three — no, about 3.6 or 3.7 — that's about 3. What does that mean? The bigger the red shift, the further out in space you're looking. A red shift of 3 takes you back ninety-one percent of the time it takes light to go from the creation event to us. Now if there's no red shifts larger than three, 3.5, that means in the nine percent of the time of the world — the universe between zero and — between 100% and 91% there was only radiation in the world, and only somewhat later have the galaxies formed, and we're seeing the time when galaxies first began to form, so maybe with quasar — you can find that time in the history of the world, before which there was any matter present. Now that would be tremendous, and quasars being clearly the most distant things — that is, there's a controversy as you know, but it's a crazy controversy. Quasars are nuclei of galaxies. They are the cosmological red shifts and we are looking back through space ninety-one percent of the to the creation of the event. Now that's really grasping scientifically something really fantastic about the history of creation. Now that's not speculation, I mean that's science. That's within the realm of science, so maybe quasars themselves will have something to say about these fundamental things in creation, about creation.
Unknown: Would you feel that somehow this was sort of tangential to —
Sandage: Not now. I did for about ten years, but not now because if one really can use them to —
Unknown: — isolate the time of information of galaxies.
Sandage: That's right. It's in the same single-minded approach to the inquiry into the creation events that the Hubble constant and the deceleration process and the age of the oldest stars, the age of the chemical elements is. So these great questions for the first time are open to mankind, and I think that's incredible.
Unknown: You just mentioned in passing the controversy that's arisen over the distances of the quasars and you mentioned that in your opinion this was perhaps a spurious controversy. Could you elaborate on that?
It is so popular in the press.
Sandage: Yeh, again it's a question whether there's a theory or whether this is speculation. It is of the same type as the tired light theory, with nothing within the whole framework of physics as we know it, to predict it or once having speculated on it, to go further — than only the statement. You have no way that the red shifts can be produced except by same mystical, unknown law of physics. Well, that's not science, so in the same way one says, "Oh, well, the red shift is so strange, let's invent something that isn't quite so strange — tired light, or something else — some momentum-less collision between photons and particles." By that I mean if now the light interacts with particles and loses energy in that interaction, it can't continue in the line. It has to be scattered slightly. There's no interaction that doesn't transfer some energy and some momentum and scattering. If that were the case, the distant galaxies would be blurred and would be bigger because the light is scattered. Well that's not true. They're just as sharp as the nearby ones, so there's no interaction in the light path. Well, O.K. then one abandons that type of theory, but then you always say, "There must be some other unknown explanation." Well, that's revealed religion if you like. That's faith without science. So, until these guys come up with an explanation of the red shift — first of all they don't have any scientific ground to stand on — unless there are consequences of the red shift which are so overwhelming in themselves, but there are no consequences that are so overwhelming in themselves.
Unknown: Does this really tie up with the explanation — the tired light explanation of the red shift though even if the word tired light explanation they would presumably be at cosmological distances.
Sandage: No. I meant that it was an analogous situation. It has nothing really to do with it.
Unknown: Was the impression that I got — this is purportedly ďobservedĒ opinion.
Sandage: The quasars as centers of galaxies was an idea first proposed about 1969 and in connection with the end galaxies which are — have many quasars in the center and you can see the outline structure of the parent galaxy, and then Kristian showed that the objects which were really quasars had themselves, those with low red shifts and therefore close by us, cosmologically, you can see with sufficiently detailed photographs the galaxy underneath. This third thing by Oke and Gunn which is really confirmation of the first two, shows it in what is an end galaxy. Thatís not quasar, BL Lacertae, is not a quasar. But that type of evidence is becoming more and more common and it is — even without that it was quite convincing, to me, that the quasars were cosmological distances just because of the relation in the Hubble diagram and the apparent magnitude red shift relation, and that could only be understood if quasars were composite sources, quasar in the center of a galaxy, the composite being the galaxy light and the nuclei of the quasar.
Wright: You proposed a series of tests for the Hale telescope to discriminate various world models to determine observationally the deceleration constant 90. Would you care to comment on the success then and since?
Sandage: Well, as of now it's been a failure, and although a tremendous amount of effort has gone into that, and I would say that about six years of working time for me went into trying to make those observations — the observations are all right but again it's a question of what happens to the light in the six billion years from the most distant galaxies to us in the light travel time.
We observe the nearby galaxies almost as they are today, but the distant ones we observe them as they were when light left, and that's about six billion years ago. What's happened in the meantime to the evolution of the stars, again we get back to evolution, so here's where the confluence of this whole train of evolution and the cosmological problem now come together, and until we solve this question of a change of luminosity or candle power of the elliptical galaxies and the light travel time, I don't know how to correct my observations for this evolutionary effect. So, as of now we don't have an answer via that route, but in the meantime by going that route we've learned a tremendous amount about the galaxies themselves. We know that the first rank elliptical in a cluster is a tremendously stable standard candle. Now why is that? We know that from Cluster 1 to Cluster 2 to Cluster 3, the first rank member is the same luminosity to within ten percent — no, no to within a sigma of 30%. Now God has made the galaxies all of one kind, all of one kind. Not quite as good as saying all the electrons have precisely the same mass and charge. That's an amazing thing in itself that the electrons are all identical, protons are all identical. Most elliptical galaxies are 1012 solar masses, — are 1012 solar masses to within Ī20%. Isnít that amazing? Beehives of stars, where the beehive canít grow bigger than a certain value. Now that's got to mean something which we don't understand now, but it's got to mean something about the evolution or formation of galaxies. That's come out of this work. So, the work toward 90 and the cosmic model was the motivation, but we haven't gotten there yet, and I think there's another way to get 90 or the deceleration. Not this classical way that was described in 1960.
Wright: The interpretation of the red shift to the apparent luminosity of galaxies due to the decelerization of the expanding universe, could you comment on this relative to the missing mass problem and cosmological red shifts in general.
Sandage: Yes, well, the red shift is — the phenomenon of red shift in first order is independent of deceleration. The deceleration only comes about by the whole universe acting on itself. Its own self gravity slows it down. O.K. How do we find that? We can't measure the red shift of the galaxy now and wait ten years and measure its red shift because it doesnít slow down enough. You can calculate that a galaxy will only change by ten kilometers a second in its red shift at a red shift of a thousand kilometers a second if you wait a million years, so you make an observation now, wait a million years from now and it'll change by ten kilometers a second out of a thousand. So you can't do it that way. Well, how do you do it? You look back in time and see what the expansion was a long time ago. How do you do that? You look out in space so far that the light took a tremendous amount of time to reach us, so you're sampling the universe at different cosmic times as you sample at different distances. Well, by combining all that stuff, you can see how much it's slowing down. Well, O.K. This evolutionary correction comes in, so your question was really whether the red shift phenomenon itself is related to the deceleration and it's independent. The red shift itself is independent of deceleration. The deceleration depends only on the total amount of mass in the universe. Well, my value for the deceleration without any correction, for evolution, the deceleration is too great. It would require too much mass in the universe from what's observed, so there's two ways around. There's either missing mass, which nobody can find or my value of the deceleration wrong. Now I think it's wrong. I think my value's wrong. I think it's wrong because in the six billion years that it's taken light to come, these things have changed, the absolute luminosity, so we don't know the distance. They're not at the distance we think they are. O.K. There's another way around that, and we've recently got the deceleration parameter by a whole new method, and that method is to compare the Hubble constant, the Hubble which is not 18 billion years with the age of the globular clusters — again the age of the globular clusters which is thirteen billion — fourteen billion years plus one billion for the clusters to form — so that's nineteen billion compared to fifteen billion. The difference is the rate the universe has slowed down, and that doesn't allow much slowing down. You can account for almost all the slow-down from the amount of mass that you can see, so almost no discrepancy now exists. I think that's the solution, but again it's related to stellar evolution and the age of the oldest start in the globular cluster. So that's why I think that this development 1950 is one of the central ones. You've got ten more pages there don't you?
Wright: No I don't. (Laughter)
Wright: You touched on the controversy I guess you'd say between Zwicky and yourself concerning the pygmy stars with — Was there any correlation made with neutron stars?
Sandage: Well, what Zwicky said was that a new class of stars exist, between white dwarfs and neutron stars.
Between white dwarfs and neutron stars, and he quoted examples. Now all Eggen and I did to take those specific examples which were his first candidates for neurons — for pygmies, and show that they were ordinary stars, so the results that he quoted were not were not established — well established observations. All we did was do an observation, a piece of data.
Wright: The globular cluster NGC 7006 you came up with some anomalous color magnitudes —
Sandage: (Laughter) You've sure been reading the literature (Laughter) My goodness. (Laughter) That's great. You know all of astronomy. (Laughter) Now what about 7006?
Wright: Anyway this anomalousÖ
Sandage: Color magnitude diagram.
Wright: Color magnitude diagram was due to a low metal abundance — I mean that was the reason it seemed to be anomalous. Could you comment on the significance of this relative to the helium abundance problem?
Sandage: Yes. Well it's not quite that way. It's been known for a long time that globular clusters are low in metals, and that was shown when the first color magnitude diagrams were done. That was shown in a globular cluster — NGC 40 — oh I don't even remember it 'cause I did it. Merle Walker and I found that in a distant globular cluster there was an ultra violet excess in the light from the stars and we interpreted this in terms of a low metal abundance following work that was done by Nancy Roman. So, it had been known that the globular clusters were down in metals. The anomaly in 7006 was that the metal abundance themselves — itself, could not be the only parameter that varied along the horizontal branch because it just didn't work, so there was another parameter which we speculated was the difference in helium abundance, but that may indeed not be correct. What I think the observation did open up was that there was in addition to the metal abundance and the age another parameter, and by metal abundance one really means the iron to hydrogen abundance. And now a lot of work's been done by people at Yale using the 200 inch, and I guess Yale has been the principal place with McClure thinking that it's — and Hardwicke in Victoria, in Canada — thinking it's the oxygen and nitrogen ratio. I guess the significance 7006 was that it merely opened up the other parameter aspect for the chemical composition of the stars and globular clusters, and so the chemical history of the galaxies may be more complicated — not only more complicated — than we had thought. So this was just an initial observation which still hasn't been explained showing that game sort of a third parameter is necessary.
Wright: Well, another NGC candidate, 2403 — you had quite a bit of data on variables on this cluster in the M-8l group.
Wright: Indicated that there was same red super giants that might be used for distance indicators. I just wondered what the significance of these red super giants might be for distance moduli and time scales.
Sandage: Yeh. 2403 was the first galaxy that cepheids were found outside the local group, end it was started in 1951 with the two hundred inch. Observations were started then. It was finally worked up in 1968 by Tomlin and myself and the red super giants are present and all of the same absolute magnitude no matter what the parent galaxy is — the absolute magnitude of the parent galaxy. Now we thought that was true in '68, and it's almost certainly true from the calibrations that have now been done. Relative to this new work on the Hubble constant, so we've used this fact just as a fact to get the distance now beyond 2403 to M-l01 which is another giant spiral, but it gets a step now beyond. There's a local group M-1 group and now a step beyond, a 101 group, but theoretical explanation of this is still not understood so what it is that the main sequence termination points to make all the red super giants the same absolute magnitude we just don't know, but the theoretical problem and some ideas, but — that is, people have some ideas but they haven't worked them out yet.
Wright: Well, we've already talked a little bit about the helium abundance. You prepared another paper on M-3, and 13 and 15 — M92
Sandage: And M-2.
Wright: — on reddening and age difference. Could you comment on how it might have impact on the helium abundance?
Sandage: Yeh, yeh. It's not really the helium abundance per se. I guess people look upon papers in much different ways, and as the author I look upon it in much different ways from the people who read that paper, and that means that the English wasn't clear or the science wasn't clear or both.
Wright: Or maybe the person —
Sandage: No, no, no, no, no. You're not the — I mean many people have thought that paper says a lot that I didn't think it said. What I think it says is that all globular clusters are the same age. These clusters — isn't that amazing? All of these things, all of these clusters which are in the halo of our galaxy are of the same age. Now how can that be? That says something about how our galaxy came into being. Well this is the observational paper — take the observations, age dates, take the difference in the age between those clusters, and it has something to do with the way the galaxy was formed, and these observations plus others of high velocity stars would suggest the galaxy formed by collapse, and that they're all the same age, the oldest stars are all formed like a direct delta function, and if we can age date that you have something about the creation, so that age turns out about fourteen or so — about fourteen million or so. So that's what I thought the significance of that paper was, but also the helium abundance was about the same which is interesting from the big bang standpoint because helium is made out of the big bang and it should be the same in almost every environment. Well, helium abundance in the globular clusters which are the oldest things in the galaxy are about the same — is about the same as in the youngest population one stars. Now the way to get the helium abundance was discovered by Christie at Cal Tech, who is now the provost at Cal Tech but he did this magnificent thing on RR Lyrae stars and showed that the character of those stars depends on helium abundance, and one just applied his ideas to the observations. That's what came out.
Wright: In another paper you wrote about the intrinsic flattening of ESO and spiral galaxies. Can you find implications of the possibilities of galactic evolution?
Sandage: Well we tried to draw it in there, and that's — in that paper, and that paper's had a lot of criticism on the outside, and I think the critics are probably right. I feel that paper is still
O.K. (laughter) I think (laughter). The conclusion about the amount of hydrogen in the disk left over from the collapse determining the Hubble time may or may not be right. That's the point of contention, and I think that's a side issue in that paper, but maybe it wasn't. At least that part seems to be wrong. Maybe the whole thing's wrong, but I don't think so. Well, I don't know, I don't know, maybe — I think the observations are right, and I think that the percentage of elliptical galaxies in the various classes are O.K. and that was one of the thrusts of that paper, but I think the vast conclusions are always suspect, and we tried to draw vast conclusions in that paper and that is undoubtedly wrong.
Wright: Well, you did some a continuation of some of Baadeís work on the Local Group galaxy IC 1613.
Sandage: I was just really a reporter there because Baade died and hadnít worked up his material so it was just prepared for publication.
Wright: But you estimated the dimensions of the galaxy made up of the populations I and the population II stars.
Wright: Can you comment on the implications for stellar evolution from those findings?
Sandage: Well, itís Baadeís old story, and it really is the story of Baade, that in the Local Group where you can see a lot about the stellar content, all of the galaxies seem to have this background sheath of old stars. The same stars, the globular cluster type stars that he isolated for population II, resolved in M31, that I did my these on in the globular clusters, that is age dated as the oldest component, and what he found in IC 1613 was regardless of the recent star formation which you can see over the whole of the face, there is this uniform background sheet of the population II which from the type of resolution he could tell how bright they were and therefore we could age date. And that is guess what age that is, that is the same age fourteen billion years. The same sheet thatís present in the Large Magellanic Cloud, the shame sheet is present in the Small Magellanic Cloud, it is present in our Galaxy. You can see it in the RR Lyrae stars perpendicular to the plane. It is present in Andromeda, it is present in M33, and it is present in this galaxy IC 1613. So something happened of a crucial nature. Most things came into being at that initial burst of star formation, so I think what Baade opened up couples directly up with what Hubble did and although we said earlier that Baade thought what Hubble did was a mistake and that way to get at it was another way, whatís now happened again is that these two divergent thoughts have again come together. The evolution and the background population II have come together with the expansion of the universe to say something fundamental about something fundamental about some early event in the history of the world. Those guys were not so far apart as they thought they were.
Wright: From scattering models for galactic halos, do you feel that the models could be consistent with Ostrikerís hypothesis for the missing mass?
Sandage: Well, I donít understand Jerryís hypothesis. What one normally needs for the missing mass is a factor of thirty to fifty, and Ostriker is talking about factors of three, so what heís saying is that disk galaxies are unstable, dynamically Ė the only way you can stabilize them is by making a whole bunch of stuff in the halo. That is a theoretical statement. He says O.K., Iím so convinced of that result that ipso facto all galaxies must have big halos. Letís go out and observe them. Well, they were just here four months ago, and nobody know the result. So, first of all one doesnít know whether itís true. Secondly, one doesnít know whether the theoryís right although those guys are really good. You believe Ostriker before you disbelieve him just because he is Ostriker, but still if all he needs is the factor of three to stabilize the disk, thatís a long way from the missing mess. But he claims he can get the whole missing mass, and I donít know the difference in the way Iím thinking of what he says and what he believes, but heís a good — a very good man, so I donít know.
Wright: Your scattering results donít indicate the presence of these large labs?
Sandage: I guess I donít know what you mean by scattering results now.
Wright: You wrote a recent paper, I believe I just read the abstract I am not familiar with the entire paper. It was a study of the scattered light from the environment of galaxies.
Sandage: No, that wasnít me. No, I donít think so. Maybe my ghost writer (laughter)
Wright: Very certainly you are correct.
Sandage: (Laughter) But you donít believe it. You just donít believe it.
Wright: Perhaps I misread the abstract. Yes, Astrophysical Journal 15 August, 1972.
Sandage: Whatís the title of the paper?
Wright: Linear Polarization of the Hydrogen Alpha Emission Line.
Sandage: Ah, in the halo of M82, with Visvanathan. Thatís a very peculiar galaxy. O.K. Thatís the scattering of an exploding galaxy of electrons up in the halo, but thatís not what Ostriker is talking about. Heís talking about stars.
Sandage: And M82 is like nothing else in the universe.
Wright: So — so one would not expect —
Sandage: No. No one doesnít say anything about normal galaxies from anything you observe is M82. Thatís a whole different kettle of fish. Thatís an amazing result; thatís an amazing galaxy, but that has nothing to do really with the missing mass.
Wright: In the popular press and also is some journal articles thereís discussions about black holes as being an issue of interest. Would you care to characterize to comment on what you consider to be the really hot issues in cosmology today? What Iím saying is that black holes are not necessarily or — you may not think that they are a hot issue today.
Sandage: Yes, they are a hot issue all right. Black holes are interesting in two different ways. Theyíre interesting as a detail in the whole of the enveloping structure of the world. By that I mean the x-ray sources are interesting because theyíre physical things, but the little, little cross-word puzzles somehow, of the way matter has put itself and together and gives interesting things. And stars are interesting too, but thatís what most astronomers, in fact that is what all astronomers study sometime or other, but itís got to be related to some bigger — bigger thing. Well, black holes are interesting just in the same way stars are interesting in that aspect, but they are also interesting because it is real, then it says something very strong about Einsteinís theory being right, and if Einsteinís theory is not right, then we donít know very much about the large scale structure of the world because in — if you like, the universe is a black hole. You calculate the Schwarzchild radius of the universe — it is the Hubble radius. No light can get out of the universe. Now, thatís why it canít get out of the universe. Oneís heard the statement that lightís confined to the universe and you canít see out. Well, thatís the reason why you canít see out, because weíre inside the black hole — a black hole — the whole universe doesnít exist? Well, thatís a Berkeleyite type assertion. No, no, thatís not why theyíre interesting. Theyíre interesting because they would say something about the validity of what we all take to be the most precise description of the large scale structure of the world and if thatís wrong then weíre wrong. You know the greatest generalizations of science have almost always historically been incorrect. Only the very, very few that we now believe from history books have risen pristine out of all the muck. And what is that? Newtonís law of gravity. The way you calculate elliptical orbits, Keplerian orbits, the Lagrangian Equations, the Maxwell equations are only the latest attempts of an enormous number of failures, but those are failures too in a certain sense. In a certain sense the historians of science are doing a bad thing by picking out one or two people and one or two ideas when itís just — just a whole — the whole flow of things that are right which prove that theyíre right by — by just their actions. I canít explain what I guess I mean, but the fate of history on whether — no, no, Maxwell was certainly a great man, and Newton was certainly a great man that you guys donít recognize somehow. Have you ever heard of — only recently has Bolyai been understood to be in the same class as Lobachevsky and Riemann in non-Euclidean geometry. But oneís hardly ever heard of Clifford.
Wright: W. K. C. Clifford?
Sandage: Yeah. Itís pre-dated Einstein, I mean whose ever heard — well, you have, yes.
Wright: Historians of Science.
Wright: They only make it into the professional literature and not into the more general types of literature itself. Clifford is a very — a very interesting person. Pierson did some work in a similar vein, too.
Wright: Yeah. Heís more well-known for his work in biology curiously enough. He came up with a theory of — a theory of gravitation called the ether squirt theory which in many respects resembles Einsteinís approach to gravitation.
Sandage: Sure. Well, and also unless one does a really mountainous piece of work like Einstein surely did, the general level of understanding just goes up by small perturbations, but it still continues to go up, and so the predecessors of an idea are almost impossible to trace, and then thereís a tendency to ascribe it all to one person. Now, certainly Newton was one of a kind, but one really doesnít know about Hooke, Boyle, and Gay-Lussae and all these guys that have their names on equations in physics books. Who knows that may not have been Joe Schmo around the corner.
Unknown: Newton made some tremendous contributions with many of the ideas which are routinely attributed to him were extent at the time. For example the conception of inertia formulated by Descartes several decades previous to Newton. Youíre right aside from pedantic professional literature there are a lot of people in the history of science who go wanting.
Sandage: So, all these ideas in astronomy, for example, cosmology — current ideas are the result of an awful lot of people, and I guess I would consider myself to be a moderately effective engineer in the sense that I can take the things that are extant, thought that are going around, and apply them in some concrete way with the worldís biggest telescope, and so very -Ė very little I think is original in the way that Hubbleís really was. Hubble was an original man. But even that is a product of his own writing in ďThe Realm of the NebulaeĒ and of the historians that have now written, because he had a lot of predecessors that almost were there as well, and he — he makes a very — if you read the ďRealm of the NebulaeĒ carefully you will see that he tries to show that his predecessors really were not quite as close as they were. Now his predecessors really were not quite as close as they were. Now that is an unfair thing, but his criticisms of his predecessors, before he really had made it were interesting. Were really interesting. But thereís no question about it, he was really a fantastic man. But so was Lundmark, he almost had the expansion. But Lundmark had the distance of the Andromeda Nebula. He really had that. Curtis understood the nature of galaxies. I think Hubbleís great thing was that he codified things in a stylish way that everybody could understand at the time. So the style is as important as the ideas, I think, in the acceptance of things. And a stylish man is more successful than an original man often.
The second thing Iím proudest of, if you want some statement like that, is a paper that was written with Lynden Bell and Eggen called ďObservational Evidence from the Notion of Old Stars That the Galaxy Collapsed.Ē Now this paper takes stars that you know are old, because theyíre related to globular clusters and we know how to age date the globular clusters, and finds the parameter of the galactic orbits. O.K. A star will not change its galactic orbit in its lifetime because it doesnít interact with anything. So, the ellipticity of the orbit is the ellipticity it had at the time of formation. You can show that the oldest stars are moving on highly plunging orbits toward the center of the galaxy. Young stars are moving on circular orbits confined in the place. Also old stars are low in metal abundance. Young stars are not. So isnít it curious that the metal abundance of a star is related uniquely to the ellipticity of its orbit. Now thatís got to say something about the whole history of the galaxy, and it does say something very fundamental about the whole history. So not only can we age date creation and find the oldest stars but we can see exactly what happened in the formation of our galaxy by studying the motion of the stars and understanding chemical evolution of the galaxies. Isnít that wonderful?! Thatís wonderful?! How you have a spiral formed after the first 107 years of its lifetime, out the whole 1010 years of it is going and the tidaling inter-actions of some passing galaxy — some passing galaxy will set up — set up oscillations in the disc, and those oscillations are then self-contained in a plasmic way and go through the whole density —
Wright: Uh-huh. So in other words what youíre saying that the spiral wave theory will only work for a galaxy which initially is a disc.
Sandage: Well, which initially has gas and dust, because —
Wright: The disc must form before the waves can be set up and give you the spiral of the spiral structure.
Sandage: Ellipticals have no — no green gas nor free dust. Thatís another interesting point that it all the materials has been formed into stars but the thing that is perturbed which causes the compression is the gas, not the stars, so the new star formation forms in the spiral arm at the point where the things compress upon one another by the action of the spiral waves which is triggered by the — by some passing influence, so what he says is right is out of elliptical galaxies.
Wright: Well, this next question is rather a mean question, but Iíll say it anyway. Do you foresee any observational evidence that might drastically change the world models in the future?
Sandage: Yes, I think the world models are a figment of our imagination, and I think that cosmology is on a much different place than knowledge or understanding of stars or knowledge and understanding of the processes of star evolution or even stellar content and digital scales to galaxies. I think the whole world model bit is in a pre — not pre-scientific, but thatís the next phase that we havenít gotten to, so I think an awful lot of things can happen. I think itís true to say that a cosmologist will never be believed unless he becomes a cosmologist very late in his scientific career and has done something of a rigorous nature before, — and I donít know weíve really gotten very far.
Wright: In Otto Struveís book ďAstronomy of Twentieth CenturyĒ he quotes you as saying "the modern history of astronomy will be one of the great stimuli for students who of late just do not read the literature either current or ten years old." I know that you don't normally see students, but could you verify the accuracy of that quotation?
Sandage: (Laughter) Well by verifying the accurate, if you ask did I say that or did I write it — yes, I said it and then I wrote it, but — but whether itís true in the truth of the statements —
Wright: Well I was thinking first, sort of a two pronged question I guess youíd say —
Sandage: I know what you mean. Yeh, thatís an accurate quotation.
Wright: Well, then, — uh —
Sandage: I donít know — what Iíd say now —. I was terribly young when I said that, and maybe I didnít read the literature — at that time, but I think the students are tremendously smart these days, and whether theyíre smart just because they are smart — or they know whatís going on. They know whatís going on a lot more than the people that are working in narrow research fields. Now maybe they have to be to get by, but the students are better now than they were twenty-years ago. Thatís really quite clear — and no, I donít think that the students know anything about population I and II. They donít know anything about what astronomy was like twenty years ago, and astronomy was much different twenty years ago that it is now. So — so in that sense I donít think they have any appreciation of the cultural shock that theyíre helping to create or science is going through, so, so in a sense — well you guys donít either. So, I think you guys canít write the history of science. I mean I think itís got to be a scientist going through that period to somehow think itís got to be a scientist going through that period to somehow reminisce the way science was. Not reminisce by talking into a thing but by writing, somehow. Weíve got an enormous number of papers up in the attic — letters of the whole history of the observatory, but I think if some outside person were to come in and try to do something it wouldnít work. Itíd have to be somebody that lived through that period to understand really what Baade was saying, to understand really — really the ignorance before, and the understanding after some event.
Wright: Itís a pity, I think, that Dr. Richardson has — he is — has an interest in writing, but he doesnít have an interest — well, I donít know him that well, but he is more interested in writing novels than he is in writing histories of astronomy.
Sandage: Thatís right, thatís right. But, the whole — well — you canít understand what a beautiful opera it was, if you like to put it that way, in the unfolding of just the understanding of the Hertzsprung-Russell diagram. The understanding of that diagram — really understanding, changed the whole face of astronomy to become a science. It caused the getting the main sequences to mean something deeper than just finding a relation. It said something fundamental about the formation of our galaxy, and that understanding came I think when I was learning, during my apprenticeship, and there was a terrible excitement in the air just like there was in physics when quantum mechanics were being discovered. That excitement for astronomers was so great because everything that they were taught in the way of isolated facts made some sense. It was the whole putting together of the final puzzle, and that was really incredible. You can write about it and say about it, but you donít know what it was like unless you were there. I donít know how to make people get there. They werenít there. Nobody listening to this was there (laughter) but thatís — thatís what happened in astronomy in this period like quantum mechanics.
Wright: You put your finger on one of the most difficult problems in history.
Sandage: Well somehow that feeling in quantum mechanics, but only — only students of science can understand the history of science on had to have a good solid scientific background, and preferably had actually done some science.
Wright: In order to have a feel for the discipline because it isnít in many respects like most other disciplines.
Sandage: And also to read the history of science and to appreciate it, I think youíve be got to be a scientist.
Wright: You certainly have to have scientific training. I donít see how it can be done otherwise.
Sandage: Yeh, yeh. Thereís a really interesting thing I read a little while ago this is clear off the subject. You know the guy who discovered the spin on the electrons?
Sandage: Yes, but they didnít really. The guy who did it was a guy by the name of Kunig, and he went to Pauli and said ďHey how about this?Ē And Paul said ďNo, it wonít work. Terrible, you know — an awful idea, (laughter) you sit.Ē (laughter) And the guy believed him, you know, and Kunig then wrote the history of this subject of ďGreat Historical Moments in the 20th Century Physics,Ē but that isnít quite the name of it, and he tells this story on himself but he really tells it against Pauli, of course, and the whole book is full of things like that.
Wright: As a matter of fact I understand that was the reason Muhlenbeck were not awarded the Nobel prize.
Sandage: No, is that right?
Wright: Because of Kunigís work and it was known that he had done.
Sandage: Yes, but he didnít believe it. He didnít publish it.
Wright: Pauli dissuaded him. Thereís an interesting point there too, because itís, as I understand it H-M after they submitted the paper sat down and did a calculation using classical radius of the electronics and discovered that if you looked at it as a classical particle that the surface velocity would exceed the velocity of light.
Sandage: Yes, yes.
Wright: They had second thoughts about withdrawing it. But it was too late.
Wright: And then decided well, you know, what the hell, weíll let it go.
Sandage: Gee whiz. Well, thatís kind of like Carl Anderson sending in the notice to the ďPhysical ReviewĒ about the discovery of the positrons and then he had second thoughts and actually, from my understanding, wrote and telephoned to have it withdrawn, but it was already set up and printed and on the stands.
Wright: I wonder if you care to comment on your current work in Chile?
Sandage: Ah hah. Thatís the greatest astronomical site in all the world.
Wright: Is this Carro-Toledo?
Sandage: No, this is the Campanas observatory of the Carnegie Institution Southern Observatory. We have started out Southern station and itís — Carnegie Institute started the station — forty inch, and thereís a picture of the forty inch. You can see the dome and its rough cement work. Itís called rustic Chilano, instead of modern finish, but itís a really great telescope, and now a hundred inch telescope is going into operation about the middle of 1975, and all of us here are trying to design the auxiliary instruments, and itís going to be of a unique design. Itís going to have twenty-inch plates. The field is going to be good over twenty inches, and itís going to have the depth of the two hundred inch because it has the same focal length. And the information capacity or rate, even though itís a hundred inch is going to be sixteen times greater than the two hundred inch for — for surveys. On axis itís four times less of course, because itís smaller. So thereís a lot of problems involved in that and the first thing I want to do is to — is to relate the zero points of the RR Lyrae stars with the classical cepheid and check those zero points. Now, the metal abundance of the Small Magellance Cloud is supposed to be smaller than the large. Does that have anything to do with the zero points Period-Lumpity relationship. It if does then everything we think we know about distances to galaxies goes up including the Hubble constant business that we just finished with [???] but thatís — thatís what we are going to do — and well, weíll see. So maybe we start all over again, and maybe — maybe even the time scales are wrong. But it keeps us off the streets (laughter). Itís a harmless activity. (laughter)