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SPEAKER: This is a production of Cornell University.
CHARLES JERMY: Welcome to the third of the Summer Session lecture series. My name is Charles Jermy, and I'm Associate Dean in the School of Continuing Education and Summer Sessions. We're happy to be here tonight.
We're also grateful to Dean Kathryn Boor for the use of this hall. It is a very generous gesture by the College of Agriculture and Life Sciences.
[APPLAUSE]
Jonathan I. Lunine is the David C. Duncan professor in the Physical Sciences at Cornell and the Director of the Cornell Center for Astrophysics and planetary Science, the author co-author of four books, and author of three-- well, co-author of 300 papers. He is at the forefront of research into how planets form and evolve, what processes establish and maintain habitability, and what kinds of exotic environments, such as methane lakes, might host the kind of chemistry sophisticated enough to be called life.
His work includes the analysis of brown dwarfs, gas giants, and planetary satellites. Within this solar system, bodies with potential organic chemistry and prebiotic conditions, particularly Saturn's moon Titan, have been subjects of his investigations. He pursues his research interests both through theoretical modeling and participation in spacecraft missions.
Jonathan also serves as the David Baltimore Distinguished Visiting Scientist at NASA's Jet Propulsion Laboratory. He works within interdisciplinary-- as an interdisciplinary scientist on the Cassini mission to Saturn, and he is co-investigator on the Juno mission launched in 2011 to Jupiter and on the near-infrared spectrometer under development for the Europa Multiple Flyby Mission He is on the Science Team for the James Webb Space Telescope, focusing on the characterization of extrasolar planets and the Kuiper belt objects.
Jonathan is currently principal investigator for a proposed mission to look for signs of life in Saturn's moon En--
JONATHAN LUNINE: Enceladus.
--Enceladus, and he has contributed to concept studies for a wide range of a and extra planetary missions. Jonathan is a physics graduate of the University of Rochester and he has a Master's and A PhD degree in Planetary Science from the California Institute of Technology.
He's a member of the National Academy of Sciences, and he has chaired or participated in a number of advisory and strategic planning committees for the Academy and for NASA. And he's here tonight-- Jonathan Lunine.
[APPLAUSE]
The Big Bang Theory and the Priest Who Fathered It.
JONATHAN LUNINE: Well, thank you, Charles. It's really a pleasure to be here tonight. Let me start with two stories.
The first story is that in my parish-- I'm a practicing Catholic-- I gave a talk on another Catholic scientist. And one of the high school students-- it was a youth group-- came up to me afterwards, and she said, I really appreciated your talk because my boyfriend told me that I couldn't be a scientist if I believed in God. And I said, well, he's wrong. She became a history major. But anyway, I was clearly very inspiring to her, but her boyfriend was wrong.
The other story is I'm taking a hike one day with a group, and this young fellow, who learned about my background, came up to me and said, so Catholic, scientist-- how does that work? And initially, I wanted to say, it works very well, thank you. But I thought he'd think I was being sarcastic. So I explained about all the Catholic scientists.
So this talk is a kind of a formalized version of those experiences. And this is the right place to do this because some of you may know that Andrew Dickson White, our very first president wrote a treatise entitled "A History of the Warfare of Science with Theology in Christendom" in 1896 which is actually a very good read. I kid you not.
I mean, it goes very fast. It almost reads like a supermarket novel because it's very dramatically written. And it's not really what you expect because at the end he decides that science and religion together each have their place and have to work together. What he was railing against was orthodoxy and dogma that was impeding the progress of science over the ages, and superstition, and so on.
But it's fair to say that in the last 10 years or so the whole discussion about science and religion has taken a much more bitter turn. And now I'm getting serious because this is an issue that I think is beginning to affect in much the same way that the polarization between Democrats and Republicans is affecting the ability of our government to function. It's affecting the ability of people to have a dialogue with each other.
So let me give you a very quick example. This is a quote from a book-- The Nature of Space and Time, 1996. This is Stephen Hawking the famous scientist in a debate with Roger Penrose. And at one point Stephen Hawking-- who's been hectored by Penrose about Schrodinger's cat, and it's important whether it's alive or dead or not-- says, "I don't demand that a theory correspond to reality because I don't know what reality is. I'm concerned-- all I'm concerned with is that the theory should predict the results of measurements." And that's an excellent description of how science is done.
But now let's fast forward 14 years later, and Hawking has written a popular book with another physicist called The Grand Design, in which they say, "What is the nature of reality? Where did all this come from? Did the universe need a creator? Traditionally, these are questions for philosophy but philosophy is dead." Scientists have become the bearers of the torch of discovery in our quest for knowledge."
I think you can see the difference in how the role of science is circumscribed in the first quote versus the second one. And if you, in fact, look at some analyzes of the way that scientists are regarded in society-- this is from a paper by Austin Hughes, who's a biochemist at South Carolina, passed away a few years ago-- he pointed out, "There's a growing tendency to treat as scientific anything that scientists say or believe."
And by the way, that means everything I say tonight you will all believe, right? But this is a serious problem because scientists will say a lot of things out of school that are not part of their background and training. And some of that includes things like science and religion are so incompatible that we either have to get rid of religion or we have to somehow wall it off.
So what I want to do is profile a remarkable scientist who was a Catholic priest, Georges Lemaitre, who I think provides a very effective argument against that line-- if I can call that line-- of reasoning. And it also provides a very, very interesting and at times almost comical look into the way that priority and credit is given in science for major discoveries. He was a Belgian mathematician physicist who is now finally again widely credited with being essentially the inventor of the Big Bang model of the formation of the universe.
So a very brief biography-- he was born at the very end of the 19th century in Charleroi, Belgium, went to a Jesuit high school. He then volunteered at the outbreak of World War I and served in the infantry in the Battle of [INAUDIBLE] and then went into artillery and was discharged in 1919. He then went-- he then actually went and got a Master's degree in math at the University of Louvain, 1920 in Belgium.
After that, he fulfilled what had been his childhood intention, which was to become a priest. He was ordained in 1923. And he was able then after his ordination to get both time and funding to pursue research abroad. He went first to Cambridge, England and worked with the famous cosmologist Arthur Eddington.
He then moved on to Cambridge, Massachusetts and worked with Shapley at Harvard College. Harvard College at the time didn't award PhDs. Some of us think that they really don't award them today either, but they really didn't award-- Harvard didn't award them back then. Sorry, if anyone's a Harvard grad, I was just kidding.
So he had to go across town to MIT to actually get his PhD which he got in 1927. He then went back immediately to Belgium and became a professor, which is where he did his career until he retired in 1964 and died in 1966.
Among his prizes he won the Francqui Prize-- and I apologize for anyone who's francophone here. My French is terrible, but I'm doing the best I can. I can tell you that that prize-- for which he was nominated by Albert Einstein-- at the time was actually the second most lucrative scientific prize after the Nobel Prize. And then in 1953, he was the first recipient of the Eddington Medal of the Royal Astronomical Society.
Now despite all these awards, remarkably, he was forgotten in the '80s-- '70s and '80s. He died in 1966. And if you look at astronomy textbooks and accounts of the Big Bang model-- for example, Stephen Hawking's book A Brief History of Time he's nowhere to be found. And he was rediscovered in the late '80s and '90s. And there was this almost tidal wave of articles talking about things that he had done that people realize that they had forgotten he had done during his career.
So I'm going to outline those for you. Before I do that, I need to give you a brief introduction to general relativity and cosmology. Now I'm not a cosmologist, but I did actually take general relativity at CalTech with Richard Feynman, who's very famous, but he doesn't do general relativity either. He was standing in for Kip Thorne who was on sabbatical. And so some of us commented that he should have filled out the form that said he was experimenting with human subjects because it was a very interesting course. But I'm going to do my best.
So I really want to focus then on the state of cosmology at the time to give you a flavor for what Lemaitre actually did. So in 1917, 100 years ago, Einstein published his general theory of relativity, which was the theory of gravitation which essentially said that bodies warp space-time. They do so in such a way that we get this illusion of attraction. Bodies attract each other, and light actually will be bent as well.
And so these were very, very different from the prevailing theories at the time of gravity as a force. But they were, in fact, validated very early on. So the top figure there is just an artist's illustration. The usual thing of visualizing space as a rubber sheet with the Earth as the mass distorting space and a satellite orbiting around it.
So in four-dimensional space time, which is what you have to work in, light, for example, will move along what's called a geodetic, which could be the shortest or longest distance but usually think of it as the shortest. But in space, that light is not traveling in a straight line. It's bent, and it's bent essentially along those features that you see, the way the rubber sheet is bent.
And we know that happens because we can actually see it now. So the bottom figure is an image from Hubble. The bright brown thing in the center is a foreground galaxy, and there's a background galaxy, which if there were no general relativistic effects, you wouldn't be able to see because it would be blocked by the foreground. But what the mass of the foreground galaxy is doing is that it's bending the light from the background galaxy much the same way that a lens would refract light and focus it toward you.
And so this ring is actually the image of the background galaxy-- this is called an Einstein ring-- which is nearly perfectly aligned with the observer and this galaxy here. So you get a nearly perfect ring.
So this is the background. This is the light from the background galaxy bent by the mass, the distorting effects on space, of the mass of the foreground galaxy. Now this was-- actually, couldn't do that at the time. General relativity was tested in other ways that I won't go into now, but it was clearly-- it was clearly working.
Now at the same time in the late 19-teens, the other issue that came up was the question of how big the universe was, and astronomers were able to take better and better pictures of things like this. This is an old photo of the Andromeda Galaxy. But before 1920, there was still a discussion about whether that object and other things that were all called nebulae-- Latin for clouds-- were inside our own Milky Way galaxy or were, in fact, other galaxies like ours.
And so the question of the whole scale of the universe depended critically on this. Was the universe essentially just the extent of our own galaxy which is this assemblage of stars and clouds of gas and dust orbiting around a common center? Was that the universe? Or were there other island universes-- what we now call galaxies-- and were we seeing them as these various condensations here?
At the time Einstein published, that was not known. And it was also further assumed that the universe was static, had been that way forever, was unmoving. Without galaxies that we now know are flying away from each other, there was no way to imagine that the universe was a dynamic place.
So the first thing that Einstein did in his papers was to try to put together a model of the universe using general relativity. And he immediately ran into trouble because when you put matter into this space-time framework, it's going to distort space-time in such a way that space-time will collapse on itself. And the only way, in the case of a static universe, to stop that from happening-- which is what Einstein assumed is that it was static-- is to introduce an extra term into his equations that's called the cosmological constant.
You'll see where that goes. It's sort of a piece of geometry that you tack on to the geometry of space-time that provides an equivalent of a repulsive force and holds the universe up. Einstein didn't like it, but he didn't know any other way to do it.
Now around the time that he published this, a Dutch astronomer Willem de Sitter, who had understood general relativity and began working on solutions, published a different solution to the problem of collapse in which he postulated four-dimensional space-time, satisfied the field equations of general relativity, and had absolutely no matter in it whatsoever which made it easy because then it wouldn't collapse. The problem is evidently there's matter in the universe so this was a very idealized model.
The argument was maybe the universe was very dilute, and you could just put a little bit of matter in it. And what was interesting is that when you put a little bit of matter into that de Sitter universe, it tended to all fly apart.
So those were the prevailing models up until 1920. And in the early 1920s, a Russian mathematician, Alexander Friedmann came up with a completely different alternative. He assumed that the universe was dynamic, that space and time were moving.
And so he published a number of solutions to Einstein's equations-- which included collapsing universes and expanding universes with a positive curvature like a ball, a negative curvature like a sphere-- like a saddle, and so on and so forth-- but which didn't require a cosmological constant because he assumed that space and time were actually expanding. And so he could put matter into that universe and not have the universe collapse on itself, at least in his expanding universe solutions.
Friedmann published this work. Einstein was aware of it, but almost no one else was. He died in 1925. He became ill and then passed away, and he had never actually had contact with astronomers who were beginning to determine the actual scale of the universe and beginning to find that the galaxies actually were moving apart from each other.
So Freidmann's solutions were not known to Lemaitre when he, in 1925 and 1927, also published expanding universe solutions. And in his case, what he realized in reading de Sitter solution, was that de Sitter had violated one of the assumptions you must always make in these universe models, which is there's no special place in the universe.
The universe is homogeneous and isotropic-- that's the assumption-- and every place is just the same as every other. There's no center. Think of a surface of a balloon as the universe, OK? There is no center.
So he had made a mistake essentially, and Lemaitre found that when he transformed coordinates in the de Sitter model, he came up with a universe that had no center and was actually expanding. And so you come upon an expanding universe model, but more than that, Lemaitre by then was already in the United States, and he was interacting with astronomers who had data on distances to galaxies and also the recession or the spreading apart of galaxies.
And Lemaitre's big insight was that in this model that he had put together for the universe, this expanding universe model, that it should be expanding in a uniform way such that the farther away a galaxy is, the faster it should be moving away from us. And in fact, it should be just a linear dependence. The recession velocity of the galaxy from point of view of any observer at all should just be proportional to the distance to that galaxy.
So that's all in the 1927 paper. But I want to take a very brief detour and just briefly tell you how it is that distances and velocities are measured in the cosmos.
So distances are measured using a variety of techniques that when put together are often called the cosmic distance ladder, And that arises from the fact that the techniques that you can use to determine the distance to astronomical objects that are relatively close to us are different from the techniques that you have to use for ones that are farther away. And generally the ones that are closer are the more reliable techniques.
And so if you can overlap these techniques, you can essentially build a ladder that gets you out from our solar system to the nearest stars to the rest of the galaxy to other galaxies. And if this were a class in astronomy here at Cornell, we'd go through each of these techniques, but we only have 45 minutes so not going to do that.
But Edwin Hubble, who was one of these American astronomers, was measuring distances using a technique involving variable stars that had periods of fluctuation that turn out to be directly related to how intrinsically bright they are. And so from the period of their fluctuation, you could tell their intrinsic brightness. By measuring their apparent brightness, you get their distance.
These are called cepheid variables, and that's what he was using. That's how he determined that Andromeda is a galaxy outside the Milky Way and not part of our galaxy. So distances to about 40 galaxies were measured by 1927.
And there is also an opportunity to determine the velocities of these galaxies relative to us, and that involves using the spectra of galaxies. The spectrum of an object is the distribution of light as a function of wave length or color.
So if you imagine that this is a spectrum where we've just marked the red part as being the longer wavelengths and the blue part as the shorter wavelengths, luminous objects like stars-- which are the dominant component of galaxies that you can observe at least-- they will have characteristic features where the light is either dimmed or brightened at certain wavelengths that are determined by what elements are present in those stars, and therefore, what energy of light these elements are absorbing.
So you might get a pattern that looks something like this. Here's a dark line, another, another, and so on. This is obviously simplified. Now if that galaxy is moving away or toward you, if there's relative motion, then the wavelength of light will be either stretched out or it will be compressed. And if the galaxy's moving away from you, the light is stretched, that is what's called a red shift. If it's an actual motion of the two objects, it's a Doppler shift. And what that does is it uniformly takes this pattern of lines and it shifts the whole pattern toward the red end of the spectrum.
And so the extent of this shift is just proportional to the velocity normalized by the speed of light. And so in that way, it's possible to determine how quickly galaxies are moving toward or away from the Earth.
But there is an ambiguity. You can have galaxies that are actually moving in space or as Lemaitre realized, you could have space itself expanding because his solutions to Einstein's equations had an expanding universe. And in that case, the source of the wavelength shift is a little bit different.
So here's a simple experiment. Here's a balloon I'm holding. I've put two dots representing two galaxies. Here's light of a given wavelength that's propagating from one galaxy to another. And the wavelength is given [INAUDIBLE] distance from one crest to another crest, and I've drawn that as a blue line.
And then I inflated the balloon a bit, and I took another picture, and you can see my thumb is the same size here. And now if you imagine that the surface of the balloon is the universe-- and yes, it's only two dimensions, but let's think in two dimensions for the moment because it's very hard to do this in four dimensions. I'd have to have a four-dimensional balloon that I'm inflating with a three-dimensional surface. But I'm not a magician.
What you can see on the surface representing the expanded space is that now the wavelength of light has been stretched out just by the expansion of space. And the wavelength now is given by the red line, and if you compare the red and the blue line, you can obviously see that the wavelength has become greater, and so the light is redshifted. And again, Lemaitre knew that in his model, the velocity of a receding galaxy is going to be proportional to the distance away from us-- linearly proportional.
So he published this relationship in 1927, but the canonical story in astronomy is that this speed-distance relationship-- that the speed of the galaxy is just equal to the distance to the galaxy times the proportionality constant-- was first arrived and published by Edwin Hubble, the astronomer who was measuring the distances.
And indeed, Hubble did publish this. He published it in 1929 in the proceedings of the National Academy of Sciences and became famous for it. H became known as the Hubble constant, this became known as Hubble's Law, and this became known many decades later as Hubble Space Telescope. But this is two years after Lemaitre published his article. So what's going on?
Well, what's going on is that Lemaitre published in a Belgian journal in French, which not many astronomers, who were mostly in England and the United States, read at the time. And so he sent copies of this article to Einstein and to Eddington, his former adviser, but not many other people. And so this article was basically ignored, even though it clearly contained Hubble's Law in it as you'll see.
So as the Harvard astronomer Robert Kirshner wrote in Physics Today, "Lemaitre seems to have been severely underrated" because he wrote in a language that was not used by most astronomers-- especially in the United States where all the observational work was going on-- and he published in a rather obscure journal.
Now that would be the end of the story, except for a mistake that his former adviser Eddington made. So in 1930, three years after Lemaitre published his article, Eddington gave a talk in which he said he had discovered this expanding universe solution that was a correction to the de Sitter model.
And Lemaitre was not in the audience, but a student who was there wrote to Lemaitre and said, my boss has just republished you. This is your model. And Lemaitre then wrote to Eddington-- these are the two of them on a cruise actually, on a boat. So this is Lemaitre here and this is Eddington.
Lemaitre wrote to Eddington saying, I made these investigations two years ago. Now this happens. You know, I've been republished, and I've accidentally republished other people. But Eddington had gotten a copy of this paper from Lemaitre and evidently had read it quickly and forgotten about it.
Now we all know today that many scientists would hem and haw and say, well, gee I'm sorry, but you know that's the way it goes. That's not what Eddington did. What Eddington did was actually remarkable. He was very chagrined, and he contacted the editor of a prominent English language journal-- Monthly Notices of the Royal Society-- and arranged to have Lemaitre's 1927 paper republished in English with a statement that actually it had priority over what he had done.
Lesson for all you advisers out there, like me. OK. So that's the happy ending to the story. There's the paper, and it clearly says it was republished from the annals of the Scientific Society of Brussels, and it gives the date. And so Lemaitre would get priority, except for one thing.
The key portion of the 1927 paper in French that had the Hubble relation was missing from that article. And this is the part in French that says using the 42 nebulas, galaxies, taken from the list of Hubble-- this is Lemaitre's words, Hubble got the distance-- and Stromberg-- Stromberg got the recession velocity-- and taking account of the proper motion of the sun, which you have to, one finds a distance, a mean distance, of 0.95 million parsecs-- parsec is about 3 and 1/4 light years, ask me after the talk why we use that-- and a radial velocity, a recessional velocity, of 600 kilometers per second. And therefore, he derives proportionality constant to the relation that he has elsewhere in the paper.
And so it's definitely there. So why isn't it in the English language version? Up until 2011, this was a cottage industry for conspiracy theorists, the same ones who work on Amelia Earhart apparently. But it wasn't a conspiracy. One idea was that Hubble had deliberately intervened to get that part out of the English translation so that he would maintain priority, but that's not what happened.
2011, Mario Livio, an astronomer at the Hubble Space-- the Space Telescope Science Institute, excuse me, interested in history, wanted to solve this problem, went into the archives of the Monthly Notices, found the correspondence between the editor and Eddington and Lemaitre, and found that Lemaitre had made the edit himself. He had taken it out of the paper.
Now why would he do that? I mean, this guy isn't a priest. He's a saint, right? He did it because he kind of was a saint. He realized that by 1930 the data that he had used in 1927 was really obsolete. It was 40 objects, and if you actually plot the data on the velocity and the distance, it doesn't really look like a straight line. It just had a lot of error in it.
By the time Hubble did his 1929 paper, the data were much better and Hubble could actually show a linear relationship. Lemaitre knew it had to be a linear relationship because he had created this universe that he had embedded these galaxies in, and so he just took the mean distance and the mean velocity and divided one by the other and got the Hubble constant. But he couldn't show that it was actually, in the real universe, a linear relationship.
And so what he says to the editor of Monthly Notices-- who has the wonderful last name of Smart which is good for an astronomy journal-- he said, "I did not find it advisable to reprint the provisional discussion of radial velocities, recessional velocities, which is clearly of no current interest."
And he also establishes that he was the one who did this. He said, "I made this translation as exact as I can." And so he just felt it was obsolete, and there is no point in republishing, which pretty good.
So if you compare his Hubble constant with Hubble's Hubble's constant-- this is a plot of the Hubble Constant determined in different years from Lemaitre to today-- Lemaitre and Hubble are not too far apart. Hubble later had a determination with more generous error bars that agreed with Lemaitre.
These are all going down with time, and after 1980, you see there are an enormous number of determinations that finally settle on one number. That proportionality constant gives you the age of the universe. And the smaller the number, the greater the age of the universe. So these early numbers implied a universe that was not all that old, about 2 billion years old. We now know the universe is 13.8 billion years old from much, much better data.
But here's the other irony. Hubble gets credit for the Hubble constant, and his name is plastered on the telescope. But he didn't believe in the expanding universe. In fact he didn't understand general relativity. He was interested in the data, but he didn't believe in these models of the expanding universe which he couldn't evaluate himself.
He thought the galaxies were moving apart in a fixed universe, there were other things he thought, but to the end of his days, he never accepted the expanding universe. But he gets credit for it. You see textbooks that say Hubble figured out the universe was expanding.
And in fact, if you go to an article in the Los Angeles Times from 1941, here he is again refuting, with more observations, the expanding universe. And furthermore, the LA Times calls him a savant, which is pretty good for California. There's usually an adjective in front of that, but that's not what they meant in that case.
So the official biography of Hubble from the American Physics Soci-- Physical Society is somewhat kind to him. It says Hubble didn't discuss the implications, perhaps preferring to leave the interpretation to theorists because he couldn't do the theory. Now he deserves an enormous amount of credit-- that's certainly true-- but he doesn't deserve the credit for determining the universe was expanding.
However, Lemaitre, by this point, had all the pieces together. He knew what the implications were, he knew the universe wasn't static, he knew it wasn't infinite in time. He knew that his Hubble constant meant that some time in the past the universe was in a highly-compressed, ultra-dense state, and that that was the start of it.
And so in 1931, thankfully now in an English language journal which was widely, read he published a very short letter. This is a letter to Nature-- today letters to Nature are three pages long, but back in 1931, people were pithier-- in which he described the model of the start of the universe as what he called the primeval atom, which is where all the matter was condensed into a single, gigantic atom, he called it.
All the matter in the universe, and space and time on top of it was all compressed. It was maybe like that or maybe like that. And then something happened. In his case, he said radioactive decay occurred, and the pieces began to split apart and the universe began to expand.
Now today we know that's not what happened. This is kind of a cold start to the expansion. We know that it was some sort of inflation and explosion that led to an extremely hot start, but this is the basic idea. And he was the first to put it together. And he didn't call it the Big Bang. His detractors later called it the Big Bang to lampoon him, but this really was his model.
OK. Now Lemaitre went on to do many other things. He realized, because he was someone who was interested in the data as well as the theory, he realized that geologists were finding ages for the Earth that were greater than the age of the universe. And that couldn't be so he began to play around with his cosmology models, and he stuck back into the model the cosmological constant that Einstein so hated.
And by doing that, he was able to get a-- he was able to stretch out the expansion of the universe in a way that actually looks a little bit like the expansion we understand today. He got this very rapid early period that today we would call inflation, the universe slows down, and then the cosmological constant kicks in, and the expansion picks up.
Today we would say dark energy kicks in about halfway through the history of the universe and accelerates the cosmos. We know that's happening.
But Lemaitre went even further. He wasn't satisfied with making the cosmological constant just a geometric fudge factor. So here is a very terse way of writing the field equations of general relativity. This is a geometric term. I have these labels here actually. You didn't realize are going to be equations in this talk.
So this is the geometry. This is the curvature of space-time. On the right side of the equation is a term that gives you the matter-energy content of space-time. And these little subscripts tell you that these are all tensors, which are like vectors but even more nightmarish. There sort of vectors of vectors.
And then here's another geometric term to which there is this factor called the cosmological constant. But you don't have to make that thing a geometric fudge factor. You can actually put that on the other side of the equation and call it some kind of extra energy, a vacuum energy, that causes things to be repelled, an intrinsic energy of space. Einstein didn't do that, but Lemaitre did.
And in 1933, he published-- now in the proceedings of the National Academy of Sciences-- a paper in which he interprets the cosmological constant as a vacuum energy and more, he realized, there must be a negative pressure, a pressure that causes things not to squeeze in but go out associated with that vacuum energy.
And as Kirshner pointed out a year ago, this interpretation of the cosmological constant is almost shockingly modern. Those are Kirshner's words. That's more or less what we say today about the origin of the acceleration in the universe-- that there's a dark energy, that it's a vacuum energy, that it's a negative pressure, that it's not a geometric factor. And Lemaitre figured this out in 1933.
So he should be famous, right? What's interesting though is that his other profession of priest kind of got in the way in a way that he couldn't imagine it would get in the way. He was very careful to point out that this beginning of time was not necessarily-- or even wasn't period-- God setting of the flash paper for the universe to begin.
He said this is a physical process, the beginning of everything, the beginning of reality, the booting up of the matrix if you're a Wachowski Sisters fan. You know, we can't study that. That's out of the realm of science.
But no one really listened to him, and this highly placed official within the Soviet, the USSR, writes, "The reactionary scientist, Lemaitre, Milne, and others made use of the redshift to strengthen religious views on the structure of the universe. Falsifiers of science wants to revive the fairy tale of the origin of the world from nothing."
Hopefully, he was a better politician than a scientist. But this was the kind of thing that was going around, that because Lemaitre was a priest, he had put together a model in which the universe had a beginning. And there were a number of scientists who not only didn't like that but pointed out that there was actually no evidence for this primeval atom. And among those three scientists-- and here's another Cornell connection-- were Fred Hoyle, a famous British astrophysicist, Hermann Bondi, and Thomas Gold.
Thomas Gold-- they're shown here in 1961-- Tommy Gold founded the modern department of astronomy, was the founding director of the Center for Radio Physics and Space Research which I direct today under a different name. Brilliant guy, great ideas. The three of them got together-- it is claimed-- in a movie theater and after watching a movie which had a plot in which things kept kind of going around and around back to the beginning again figured out that they could do a cosmology model in which nothing changed.
The universe was infinitely old, would be infinitely old forever, and the way to avoid the problem of this expansion going on forever and diluting the universe into nothing, into a de Sitter space, they would just postulate that matter is spontaneously created here and there to keep the density, matter density of the universe, constant. This was called the "steady state" model, and it was published in 1948 in two papers-- Gold and Bondi and then Fred Hoyle separately.
It would seem ridiculous to claim that something could just pop into existence, but you only need one hydrogen atom every cubic cent-- cubic meter every billion years or so. So if I wait here for a billion years, maybe I'll see a hydrogen atom pop into view.
So you can't observe it. It's unobservable. So this model works.
[LAUGHTER]
It really does, OK? Now Gold and Bondi pushed this model because they didn't see any observations that confirmed the primeval data model. But Hoyle pushed it because of that reason, and it's really quite anti-religious. He said, "the Catholics and Communists both argue by dogma." That's one of his quotes. And he was a colorful character, great speaker, had a radio show on the BBC.
And one of the things he said on his radio show was that the "steady state" model was created in part as a response to a religious bias toward creation. And here he uses the term Big Bang to pejoratively refer to the primeval atom model. Now he couldn't be talking about all scientists. He must have been talking about Lemaitre, and in fact, when Lemaitre would come into a conference where Hoyle was that, Hoyle would turn to the person next to him and say, look, there's the Big Bang man.
So this was a sarcastic term, and Hoyle admits here that there was a certain amount of philosophy connected with inventing this. But Lemaitre asserted instead that as far as he could see the his model remained entirely outside of any metaphysical or religious question. An atheist could adopt the Big Bang model just as well as a believer could.
Now that would have been all. Everything would have been fine. There would have been this argument. Eventually, the Big Bang model was in fact proved by observations, and Lemaitre would have been lauded and so forth, except that the Pope ruined everything.
Pope always ruins everything. OK. So Pope Pius XII was really interested in science, and he actually would go observing at the telescopes of the Vatican astronomers. And he gave a talk to the Pontifical Academy of Sciences, which is the Vatican's Science Academy, to which Lemaitre had been elected in 1939.
He gives this talk in 1951-- three years after the "steady state" model was published-- in which he basically says that present day science has demonstrated the contingency of the universe because it has a finite time scale and a beginning associated with it. And therefore, he says creation took place and therefore, there is a creator, and therefore, God exists.
Now Lemaitre is in the audience, and he was steamed for two reasons. One is this directly associates his model with the book of Genesis. And the other is that for whatever reason the Pope didn't even mention his name when he talked about this model. Now you know he had to suck it up as far as the second aspect went, but as far as the first one went, he realized he had a huge problem.
And when the next year it turned out that Pope Pius XII was scheduled to give the opening address at the International Astronomical Union conference in Rome-- which is a huge number of astronomers-- and Lemaitre realized the Pope is going to say exactly the same thing. It's obvious.
He actually flew to Rome, he met with the Director of the Vatican Observatory and the Cardinal Secretary of State, and they actually talked the Pope down. Basically, making the point that this would create a whole ruckus in the scientific community that would contaminate the model essentially. So the Pope didn't mention the primeval atom hypothesis again to his credit.
But the damage was done, and Lemaitre's reputation as a priest somewhat contaminated people's reception of the Big Bang model. Lemaitre also by that point was in his mid 40s. And usually physicists, mathematical physicists, don't continue doing their most brilliant work. I apologize for anyone who is doing their most brilliant work in their 50s. I'm not. They usually stop.
And Lemaitre also was not so interested in the direction that the research was going to try to find observational evidence for the Big Bang. It was going in the direction of particle physics. George Gamow, for example, Robert Dicke other very well-known physicists.
That wasn't Lemaitre's thing. So he became-- he had become very interested in numerical computing. He put together a top notch center of numerical computation at Louvain. The US Air Force actually approached him with a lot of money and wanted him to work for them. He decided not to do that. And that's what he did for the rest of his career.
And in the 1960s, one of the predictions of the revised Big Bang model was that this enormously high-temperature explosion as it's redshifted away from everything-- because everything is moving away from everything else in this uniformly expanding space-- would appear to us today as a kind of a uniform radiation at a temperature of just three degrees above absolute zero. And there's nothing in the "steady state" model that would give you that.
So in 1965, two radio astronomers-- actually two radio engineers, I should say-- Penzias and Wilson-- with a radio telescope that they built in New Jersey picked up the signal and within six to eight months astronomers realized that this was the echo of the Big Bang-- cosmic microwave background radiation. By the time they did, Lemaitre was on his deathbed dying of cancer. He was literally informed by friends a few days before his death that astronomers had agreed that this was the confirmation of the Big Bang.
Bondi and Gold admitted that the "steady state" model had to be withdrawn. Hoyle never did. And Lemaitre died knowing that he was right, which is fantastic because most of us don't get to do that. Really must be a saint.
OK. So that's the story. Now I want to spend the last 10 minutes talking about his views on religion and science, how they interact, and then try to wrap up.
So again, Lemaitre did not see his model as a window into God setting off the expansion of the universe. He explicitly drew a contrast to what he called the natural beginning, drew a contrast between that and what he-- essentially, this was very lyrical, this action of God, this flick-- as Pascal called it, flick of the finger-- by which God would have put the world in motion.
Lemaitre said this isn't it. Whatever that is is hidden. And in fact, Lemaitre believe that throughout his career. If you actually go to the one of the original manuscripts of the 1931 Nature letter which is in the collection in Louvain, there's an extra paragraph at the end of the manuscript with a pen mark drawn through it. That paragraph does not appear in the published paper.
And what it says is, "I think that everyone who believes in a supreme being believes also that God is essentially hidden and may be glad to see how present physics provides a veil hiding the creation." Now he obviously didn't send this to Nature in that form. But he was thinking about sending it to Nature, and he wanted to make the point as he has said later on in interviews that you cannot see God in the beginning of the Big Bang.
And that indeed as he says later, the beginning and creation are two different things. Creation can be-- creation of everything from nothing. Ex nihilo creatio, which is the equivalent of the matrix booting up. And Thomas Aquinas said this is happening all the time instantaneously everywhere. Reality is being held up by the creator at each moment. That's different from saying that the creator turned the switch on the universe, and Lemaitre wanted to make sure that those two things were distinguished.
And indeed Lemaitre metro went on to say that he wasn't a concordance-- Concordist. He didn't believe that one should mix one's science and one's faith, but he was very clear that he could pursue both without any sort of conflict.
He said, "There are two ways of arriving at the truth. I decided to follow them both. Nothing in my working life has caused me to change that opinion. I have no conflict to reconcile. Science has not shaken my faith in religion, and religion has never caused me to question the conclusions I reached by scientific methods." He is very clear on that.
But on the other hand, his optimism that one can understand the universe was motivated by his belief in God. And this is a serious question. How is it that we can actually comprehend the universe? He accepted evolution. No question about it. So our brains evolved to hunt game and build fires and live in caves and do a little bit of advance planning for which cave you're going to go to and that sort of thing.
Why is it that that brain can do quantum mechanics and comprehend the entirety of the universe? Einstein expressed that as the eternal mystery of the world is it's comprehensibility. What Lemaitre said was that, "both the scientist-believer and the scientist-nonbeliever are attempting at decoding the palimpsest of nature--" that's that the clues, the echoes left behind-- "but the believer has an advantage of knowing that the riddle possesses a solution, that its degree of difficulty is presumably measurable with the present and future capacities of humanity."
So this is a very dramatic statement, which is that either humans were designed to be able to comprehend the universe or the universe was designed to be comprehensible to humans. You could say that this is simply a strong form of the notion that there are natural laws, and those natural laws operate and are fixed and allow the universe to be comprehensible.
He's actually saying a little bit more than that. And scientists today, like Hawking, would say-- in fact, Hawking said, there's nothing the human mind can't understand. But that's an assertion. He doesn't explain why that's the case. Why should we evolve a mind for which nothing is incomprehensible? That statement to me is incomprehensible. So I guess we didn't evolve our minds.
Lemaitre was not a literalist. He was not a fundamentalist in the sense of believing literally in the Bible and in the inerrancy of the Bible. He said, "The writers of the Bible were illuminated on the question of the salvation of humankind, but on all other questions, they were as wise or as ignorant as their own generation."
Elsewhere he says that if Saint Paul needed to understand quantum mechanics to reveal the purpose of Jesus on Earth, he would have known quantum mechanics. But he didn't have to, and he didn't know it. So the point is that the writers of the Bible lived in their time and place and understood the physical world as everyone else understood it at the time. And so the fact that they were wrong about the physical world has nothing to do with the validity of the Bible. He said that it's utterly unimportant that there are errors of historic and scientific fact in the Bible.
And then finally this was rather remarkable. This is a picture of Lemaitre near the end of his life in his computing facility. He talks about determinism and whether the universe is pre-determined in some way. And he says that the "beginning of the universe is simple, indivisible, indifferentiable--" that's his primeval atom.
"The world differentiates as it evolves. It does not consist in the spinning out. It does not consist in the decoding of a recording." The future is not recorded in the universe. He says instead, "It consists in a song, each note of which is new and unpredictable. The world made itself and made itself randomly."
So that's a pretty definitive statement and one might say unexpected for a Catholic priest but not unexpected for Lemaitre. And this, of course, contrasts with Einstein's famous statement that God does not play dice with the universe. Lemaitre embraced quantum mechanics fully.
So to summarize, Lemaitre was a pioneer in cosmology. His contributions, until recently, were not well appreciated. They've been unearthed mostly by historians and interested astronomers. He inferred what's called the Hubble relationship, he invented the Big Bang model, he expressed the cosmological constant as what we would now call it-- dark energy-- and he played around with inflation. In fact, Alan Guth, the inventor of modern inflation theory said that he was shocked to see these papers and that Lemaitre had anticipated him.
Lemaitre's publication of what came to be called the Hubble relation two years before Hubble did but not getting the credit for it is an example of what's called Stigler's law of eponymy, which states that a discovery is almost never made after-- never called after it's discovered.
OK. So the Pythagorean theorem wasn't first worked out by Pythagoras In fact, Stigler himself, who is an economist, pointed out that he didn't invent this law. It was invented by somebody else, but he decided to name it after himself to make his point.
[LAUGHTER]
So Lemaitre regarded science and religion as two paths to the truth that a single individual could pursue without conflict. You don't have to not believe in God to be a scientist. And if you believe in God, it doesn't mean that you don't believe in the findings of science or can engage in them.
He regarded his primeval atom as a natural beginning to the cosmos as he put it, distinct from this creation out of nothing-- ex nihilo creatio. He regarded the latter as something as a philosophical question that cannot be settled by physical or astronomical considerations in complete contradiction to what Hawking and Mlodinow said in the introduction to their book.
So we'll see who is right, but I actually suspect-- I'm betting with Lemaitre personally. So he was a world class scientist without being an adherent to scientism, which is the notion that science is the only valid route to knowledge. He was deeply religious. He was not a fundamentalist though.
He actively experienced both World Wars. He fought in the First World War, and he watched his [INAUDIBLE] in his apartment when it was bombed by the Allies because they confused the university with the train station. And he survived and had the presence of mind to go back to his wrecked apartment the next day and play his piano which was still OK, but it had been riddled with shrapnel.
The other professors were so shocked they couldn't teach anymore. There were two of them in particular who suffered from post-traumatic stress disorder. He cared deeply for his students, his colleagues, and his science. And this is a quote from his acceptance speech of the Francqui prize.
I like what a New York Times writer said in 1933 that the notion that science and religion can co-exist in a single individual is demonstrated not because Lemaitre was a Catholic priest-- you wouldn't believe it because he was a Catholic priest, you wouldn't believe it because he was a world class scientist-- but you would believe it because he was both. So thank you very, very much. And I'm happy to take questions.
[APPLAUSE]
Yes?
AUDIENCE: John Wheeler's The Universe as Home for Man-- was he influenced at all by [INAUDIBLE]?
JOHNATHAN LUNINE: I don't know if he was. But yeah, there are some similar thoughts in that. That's true. Wheeler wrote that in the '70s. Is that right? Or '80s I think?
AUDIENCE: It would've been before the '80s.
JOHNATHAN LUNINE: Before the [INAUDIBLE]-- yeah. You know, it was at a time when people hadn't really dug out Lemaitre's papers and talks so I suspect he was not in contact with that. Yes?
AUDIENCE: [INAUDIBLE]
JOHNATHAN LUNINE: Thank you. OK. So the parsec instead of the light year is the unit of distance that astronomers use. And it is about 3 and 1/4 light years. Now the light year is the distance the light travels in one year in a vacuum. So it has to do with the speed of light.
The parsec comes from a way of determining distance by looking at the shift of stars in the sky. So as the Earth orbits around the sun, it orbits, it makes a circle with a diameter of about 300 million kilometers, the stars that are closest in the sky to us-- if you're looking at the background-- they tend to shift back and forth a lot as the Earth moves around orbit relative to the background stars. In the same way that if you put your finger in front of your head and you move your head back and forth, your finger is moving a lot more than the background because of just the angular shift is greater for-- appears greater for near objects.
So the parsec is a distance unit. It corresponds to the distance that a star would be at if it shifted an angular distance by what's called one arc second as the Earth goes around in its orbit. And one arc second is 1/3,600 of a degree. There's 60 minutes in a degree and 60 seconds in a minute. So that's one second of arc.
So if you have a star that shifts by one arc second, 1/3,600 of a degree in the sky as you observe it over the year just due to the angular change, it's 3.26 light years away. Now there isn't actually any star this 3.26 light years away. The closest star is four light years away.
So it doesn't quite do an arcsecond. It's just a little bit less than that. But it's set by the diameter of the Earth's orbit and by this angular effect. And astronomers like it better because it connects directly with this way of determining distances to the stars called parallax. Plus it makes us look more erudite because we wouldn't use what the science fiction books or movies use, which is the light year. No, we talk in light years too. Thank you for that question. Yes?
AUDIENCE: Are you familiar with the experiment [INAUDIBLE]?
JONATHAN LUNINE: Right. So we're talking now about quantum mechanics, right?
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: Yeah. Right. So this is so--
AUDIENCE: Could you repeat--?
JONATHAN LUNINE: Yeah, absolutely. So am I familiar with the pilot wave theory? So the pilot wave theory is one way of interpreting the results of quantum mechanics. And this talk was all about general relativity. So I'm not going to talk about quantum mechanics because I didn't take quantum mechanics from Feynman. I took general relativity.
But there's this problem, right? This measurement problem where the whole framework of quantum mechanics is designed to tell you about probabilities, probabilities that particles might be here and there and so forth. When you actually observe a particle, the thing that is used to determine the probability, the wave function, collapses. And you have a definite point or a definite measurement.
And the question is how does that work because up until that point particles may be in different places, moving at different speeds with a certain indefiniteness that we can actually never reduce to zero. So one possibility is that these particles are every place all at once. Another is that model actually is just a mathematical model and the particles don't really exist until you observe them or you can't predict where they are.
And the pilot wave model says that the particle is actually a particle, but it's sending out some kind of a wave of some kind that interacts with other particles. And that is this sort of quantum incoherence that you're actually seeing. And that's-- is that essentially what the model says?
AUDIENCE: [INAUDIBLE] the experiment with a [INAUDIBLE] And they were able to take that and basically [INAUDIBLE]
JONATHAN LUNINE: OK. OK. So I'm not familiar with that specific experiment, but I think it still implies just what I said, which is that's an interpretation of quantum mechanics where the particle is not a particle and a wave at the same time. The particle is just a particle, but it's emitting this wave that interacts with other particles.
And so it's not clear to me which model of quantum mechanics is right, but I don't like that model because I like the cool idea that a particle is not just a particle, but it's a wave at the same time. And so that interpretation which I think is the Copenhagen interpretation. I prefer that but only for aesthetic reasons. All I can say. Yes?
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: No, we need a bigger--
AUDIENCE: [INAUDIBLE] we need an infinite number of [INAUDIBLE]
JONATHAN LUNINE: Well, so there are-- yes, so there are other particles that are predicted in particle physics and also in models of what happened early in the Big Bang that are so massive that they're not accessible to the energy range of the particle accelerators that we have today.
And so the Large Hadron Collider is not the end of the story. Now you know, whether we can keep building particle accelerators that will be able to create bigger and more massive and therefore, more energetic particles, that's a very interesting question.
I mean, we obviously can't go back to infinity, but we probably can build bigger particle accelerators certainly. The LHC can't be the end. The Superconducting Super Collider, which was canceled, was a significantly larger accelerator that would have gone to significantly to higher energies than the LHC. And it was canceled in the 1980s by Congress. Yes?
AUDIENCE: [INAUDIBLE] let's get back to religion and science. How might we find a way to through the media and otherwise gain greater faith in science?
JONATHAN LUNINE: Well, I think we probably have so much faith in science that we need to-- we don't need more faith and science. We need to understand how science works, and what it actually what its limitations actually are. So I think that most people who read about scientific discoveries don't appreciate the uncertainty in a lot of what we find and the sort of-- I don't want to call it a random walk-- but this tortuous walk toward understanding the world more and more.
And we also have to recognize that some of the things that pass for scientific hypotheses are really not hypotheses. The statement that this is one universe in a multiverse. Until there is a way to actually test that, which nobody has offered, is actually more of a philosophical statement than anything else.
And what's crucial is to make sure that people understand what the limitations of science are. Now that doesn't mean we can approach the multiverse philosophically. It just may mean that we have to either find a way to sample the multiverse-- although, I'm skeptical that we can do that because if the physical laws are different in different universes in the multiverse, then how do you know what you're looking at, and they're supposed to be isolated from each other-- or we have to admit that we come up against a wall of some kind.
So I think there are really two problems. One is the one I just articulated, but now I see the point of your question. There are people who dismiss science and will say that one very common quote you hear is that scientists are wrong as much of the time as everybody else is in order to basically try to refute evolution or global warming or whatever.
So that is a problem, and I think part of the solution to that is to better teach people how the scientific method works. That yeah, scientists actually are wrong about as much of the time as other people are. But they're wrong in a way that you can actually test and then correct
I mean, that's the whole point of science is that science is a kind of extreme form of common sense where you postulate something that you can test. And if it's wrong, you learn from that what the right alternative hypothesis must be or another hypothesis that might be wrong. You move from that one to another one and so forth.
That's what we really have to teach-- not that scientists have a special channel to the truth, which I think is really the problem. So I think I've achieved an answer to your question through the scientific method by a random walk looking at you and the person behind you and seeing which of my statements created a nod and which created a shake. So done it Thank you. Perfect.
[APPLAUSE]
I feel like that horse that could add and subtract. What was he called? Clever Hans? And actually, it turned out that there were people planted in the audience who would make these very subtle body movements that Hans was picking up so he knew when he was right. He knew when to stop clapping his hoof. Yes?
AUDIENCE: Back to the earlier question [INAUDIBLE]. So is the universe [INAUDIBLE] Can we go back to Lord Kelvin that said all of science is understood except for two, small [INAUDIBLE], right?
JONATHAN LUNINE: Right. And there was a cosmologist in the '50s who said that we at that point understood-- I think he said 63% of the universe or something like that. So those are very naive comments. So what's understandable is the global properties of our universe and its overall evolution and what happened at significant stages.
Whether we can ever know whether the Big Bang was a singular event or whether it was part of some sort of cyclic process-- there are models like that-- or whether in fact, it's part of a process where universes bud off of other universes, I can only quote Michael Turner, who is an astrophysicist at Chicago, who said, "These problems may be the kind that are so tough that we actually won't get the answer for three or four centuries. He actually said that.
But I think as scientists, you have to be an optimist. You know, you can't say this problem is too difficult. You have to try to work out some sort of a test. And in the case of modern cosmology, one of the things we have to find a test for is whether at the very finest scales everything-- particles, so forth-- are actually manifestations of these very, very tiny strings. Superstring theory.
That hasn't been accomplished yet, but that's something that has to be worked on because that actually ties into the question of whether the Big Bang was singular or whether in fact we passed through it from another stage and so forth. So I'm an optimist, but that doesn't mean I will stand here and say we will understand everything someday in the finite future. But we have to try.
Yes? In the back? There was a hand up. Yeah.
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: No, he says that that was the beginning and he said that there is no way to actually know where that came from. And so one of the extensions, I guess you could say, of the Big Bang model in recent years has been, first of all, to try to remove the idea that this was a singularity, something that was so dense and compressed that physical laws don't apply. But rather to think of it as just an altered end state that still can be studied with physical laws and then ask whether there's some way to see whether in fact this is a continuation of some other universe in the past or part of a process of universes that bud, that sort of thing.
You know, right now these ideas really are all kind of at the level of untestable hypotheses or almost philosophy. I don't quite want to say that, but it may be that someone will figure out a way-- studying the cosmic microwave background radiation, looking at the very fine scales.
And if our universe is actually a four-dimensional space-time structure within a five-dimensional space, which is one proposal, and other universes actually run into ours, that maybe one reason why the Big Bang occurred. You might actually see that if there are patterns in the microwave background radiation that would result from that kind of collision.
That would be really fantastic, and I'm sure Lemaitre would have been thrilled to be a part of that. If somebody said instead that they would be able to figure out why reality actually exists, why is there something rather than nothing, he would say-- and I would agree with him-- that that's a philosophical question.
Because everything we're talking about-- this universe, alternate universes, multiverses, brains and bulks and five-dimensional space-- all that is physical stuff. The question of why reality, why there is something rather than nothing, is a different question.
And there are some astrophysicists who don't understand that and have written books saying, for example, that we know that you can start a Big Bang with a fluctuation in vacuum energy starting from a zero state. Because that zero state is nothing, we have now solved the problem of how you get something from nothing.
That's not the same thing. The vacuum energy, the vacuum state, is something. It's just a different thing. And so it's a different question. Let's see. Yeah, go ahead.
AUDIENCE: You've given a real clear presentation that covers [INAUDIBLE] reputation or rehabilitation [INAUDIBLE]. Are physics books being-- is there a movement to revise [INAUDIBLE]?
JONATHAN LUNINE: So of course, physicists, in general, aren't historians. But his name is appearing in books more. And for example, as I mentioned Hawking, in the Brief History of Time, doesn't mention Lemaitre at all. I mean, he's not in there in any way at all.
And then in his more recent book, which I quoted-- and I forget which book I quoted-- but it was from about 10 years later, he actually says that Lemaitre was the person who first thought of the Big Bang model. So it is actually creeping back in, and you do see it now much more on the web and in astronomy textbooks.
So I think he is getting due credit. What I would like to see actually is to have the cosmological constant, or dark energy, named after him because he did pioneering work in that. And I don't have the time to pursue that, but it would be nice to see that happen. Yes?
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: Which aesthetic preference? The quantum mechanics one? The Copenhagen? You know, I'm not a quantum mechanician. I did get a good grade in quantum mechanics, but I actually-- I really don't work in that field. So I have to say that I look on the discussion of those models as any interested, intelligent reader would.
And so I don't-- there's nothing deeper that I can say except that my understanding is that the pilot wave model doesn't actually explain all of the experimental data. It run [AUDIO OUT]. I hadn't heard of that particular experiment that this gentleman was describing. But my understanding was that it doesn't actually explain all the data.
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: I did. That's true. Because it's much simpler to think that particles described by wave functions really are entities that at times will exhibit particle properties and at other times, depending on the conditions, will exhibit wave properties rather than imagining that particles run around the universe with little wave tails coming out of them.
That's the part that I think is hard to swallow, but I could be wrong. And as I said, it's not a field that I work in so-- and when I learned quantum mechanics, the pilot wave model had not been proposed yet. So that may be part of the bias. Yes, way in the back.
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: In this field, yeah. So people actually traveled quite a bit. There were conferences in Europe, regular conferences. There were conferences also in the US. Lemaitre himself was an unusually heavy traveler. He actually went to California, Pasadena, and at the time that Einstein was there and met with Einstein in the early '30s. They also met in some other physics conferences.
There's a famous series of conferences called the Solvay Conferences that began, let's see, it would have been right after-- right at the end of World War I-- that brought physicists together. And then all of that came to an end with World War II. Communications were really cut off, and people couldn't travel.
Lemaitre himself tried to take his family, including cousins, and leave Belgium. And it was this rather heroic effort in which they were actually killing wild chickens along the road in order to eat. And they eventually were turned back. They couldn't leave. The Nazis were already in Belgium, and the borders were closed.
And he-- after the bombing-- so when the Germans, when the Nazis came in, food was very scarce it was apparently a very harsh life. And then toward the end of the war, the Allies bombed the university by accident, and so they had to find temporary housing.
So it was really-- in Belgium, it was a survival process for a number of years, and communication and scientific meetings just didn't happen. There were volumes of journals that weren't published. The journals published in the period of World War II were thinner, or they were missing volumes that just weren't published for that year.
So bottom line-- there's a lot of travel, a lot of communication, between the two World Wars-- mostly conferences, exchanges of letters, reading journals, of course, and hardbound copy. World War II shut a lot of that down, and then it started up again very, very quickly after the end of the war. You're welcome.
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: Oh yeah. Absolutely. Yes?
AUDIENCE: Forgive me for saying this-- did you write a book about him? I'm a little confused.
JONATHAN LUNINE: No. So--
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: Yes. Thank you for reminding me. This talk is based on my reading of some of his scientific papers and papers about Lemaitre are written by others. But there are two good books.
The first one by Farrell was published about 20 years ago and really was the first to kind of put together the story of what Lemaitre did in terms of cosmology and also his life as a priest. It's actually very short, an easy read. It leaves out a lot of stuff, but it tells the story.
This one by Lambert is actually an English translation of a book published in 2011. The English translation just came out. It's a long book, and it goes into great detail on Lemaitre's life and references a lot of papers, some of which I had found prior to actually buying this book-- because I don't read French so I didn't read the French version.
There are a couple of people. There's Luminet, there, of course, is Kirshner and others who have written a number of articles on Lemaitre. I gathered some of those. But if you want learn about his life, the quickest thing you can actually do is read the preface to the Lambert book-- the preface by Jim Peebles, who's a professor emeritus at Princeton, a cosmologist, is just beautiful.
It lays out a summary of the contributions that Lemaitre are made. But it doesn't tell about his life. And so the main book itself tells all about his life and is certainly a great read. If you don't have time to read 400 or 500 pages, this one is pretty decent.
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: Please. Yeah.
AUDIENCE: First off, I want to thank you because this is wonderful. I never knew about this before. You mentioned he was friends with Einstein or--?
JONATHAN LUNINE: No, they were-- he was a junior colleague of Einstein's. So when Einstein saw this work and they interacted first at a conference, he was impressed with the mathematical solution to the equations of relativity. But he really hated the idea that the universe was expanding so he told Lemaitre that the math was beautiful, but the physics he didn't think was very good.
AUDIENCE: Because I thought with his association with Einstein maybe his popularity would have been more elevated but--
JONATHAN LUNINE: Yeah. I mean, at the time, the people working in the field in the '20s and '30s knew Lemaitre very well, and he was actually quite popular. He was interviewed in the New York Times magazine. There was a New York Times-- separate New York Times article about him.
He was a popular figure, and everybody forgot about this after World War II. World War II came along and kind of erased that, and he was not all that well known through the '50s so--
AUDIENCE: Do you think it's because he was a priest?
JONATHAN LUNINE: Well, partly. One of the points that was made was that the general public was really shocked when they found out that this mathematical physicist who had invented this expanding universe model was also Catholic priest. They couldn't understand that. But I think that increased their fascination with him, not the other way around.
The reason he became obscure is that after World War II he didn't continue in cosmology. The figures who were doing all the work in cosmology in the '50s were really particle physicists. George Gamow, a famous Russian emigre, wrote a great book One Two Three Infinity, which I read as a kid.
My mother said the type is too small. You're going to ruin your eyes. And she was right.
And Robert Dicke, for example, and some others. They were all working on the problem of what would happen from the particle physics point of view during the early stages of the Big Bang. And Lemaitre was not interested in particle physics, and I think he also kind of got bruised by the whole interaction with the Pope and then with Fred Hoyle.
And he was also, as I said, by that point in his mid 40s, and he had done an awful lot of creative work. And people often in the middle of their life go off and do something else, and he did. And it was high-performance computing, high-performance for that time. And he set up this numerical computation center at Louvain and was well-known within that field for that. But he was no longer know famous from the cosmology point of view.
Another point is that a cosmologist pointed out to me, a colleague pointed out to me, that cosmology was actually not all that popular a field to the general public in the 1950s because Einstein died in the mid 50s. A lot of the work had been done in the 30s, and the discovery of the cosmic background radiation was 10 years away. And so it actually was not something that gathered a lot of the public's attention in the 1950s. So the combination of all those things pretty much plunged Lemaitre into obscurity.
AUDIENCE: It's interesting. I mean, has there been any interviews like going back in his time like [INAUDIBLE]? What brought him to that fascination to be a priest and to do what he was doing? And was he accepted? Did other priests shun him? The Pope, obviously, didn't help him. Was he supported by the church?
JONATHAN LUNINE: Well, yeah. I mean, he was supported by-- he was absolutely supported by the church. One thing I didn't have a chance to say is that he was actually named the President Of the Pontifical Academy of Sciences late in his life. He had been elected a member in 1939, but he then became the President of it. And that clearly required Vatican approval.
He was named a prelate-- P-R-E-L-A-T-E-- of the papal household in the early '60s. And so you have to be on the in with the Pope for that to happen.
In this longer biography, the only priest who had this real conflict with Lemaitre had to do with the house that at one period they were managing were foreign students-- mostly Chinese students were staying. And the two of them had this big disagreement about how to actually run that. I mean, this was a university student kind of thing, and eventually Lemaitre just got tired of it and let the other guy be the master of that house. That's the only one I know there was really that kind of conflict.
His conflict was with other scientists outside who did have a problem with the church, like Hoyle, and we're not shy about it. Any the other questions? Is Otherwise, we'll finish. One more, yes?
AUDIENCE: So I want go back to this gentleman's question about how do we change what's happening now with the jokers-- I mean, representatives in Congress. So you said 1933 was the interview with The New York Times. That's 84 years ago. How about an op-ed now talking about this understanding of the church or understanding of religion of the scientists? I think that that's--
JONATHAN LUNINE: Yeah. That would be interesting.
AUDIENCE: [INAUDIBLE]
JONATHAN LUNINE: Maybe get Kirshner to do it. That would be better. Then I wouldn't have to do it. I hadn't actually thought about that. That would be really-- no, I've got so many things to do. Yeah, we could talk about that. O-ed pieces are hard to-- actually, maybe I'd get Adam Frank at the University of Rochester to do it. He's really good.
But yes, that's an excellent idea. That's an excellent idea if we can get The New York Times to do it. Thank you.
[APPLAUSE]
SPEAKER: This has been a production of Cornell University on the web at cornell.edu.
Can science and religion be reconciled? Astronomy professor Jonathan Lunine offered his thoughts on the subject July 19, 2017 as part of the free summer events series sponsored by the School of Continuing Education and Summer Sessions.
Lunine, director of the Cornell Center for Astrophysics and Planetary Science, looks at the case of Georges Lemaitre, a Belgian scientist and Catholic priest who conceived the Big Bang model for the origin of the cosmos. As a man of the cloth, Lemaitre faced unique difficulties in defending the theory that he helped to formulate. In his talk, Lunine explores two questions raised by this piece of scientific history: who gets credit for what in scientific discoveries, and can a scientist be religious?
