A Conversation with Dr. Robert Jastrow

by Robert Jastrow

GCMI: Why did you become a scientist?

DR. JASTROW: I thought it was beautiful. I was particuarly impressed by the beautiful diagrams of voltages and currents and magnetism. When I was a senior in high school, I came into a program IBM had set up for science minded students in which they provided support for students to do research. I had gotten interested in something I had read about the Skinner box. And so I built my own Skinner box and nearly electrocuted a number of rats.

When I entered Columbia that fall, I went to see Skinner, who was a professor of psychology and offered my services He said, "That's fine, delighted to have you, the first thing you have to do is learn calculus." So I registered in calculus and I thought it was the most beautiful thing I'd ever see. And that led me to register in turn for physics.

GCMI: Discuss some of your most important work in physics.

DR. JASTROW: I went to the Institute for Advanced Study in Princeton at the invitation of Robert Oppenheimer, and in that atmosphere the emphasis was on neutrons and protons and nuclear physics and particle physics and nuclear forces. We had a visitor one day, who gave a seminar on the results of an experiment in which protons and neutrons were made to bounce off one another, so-called neutron/proton scattering experiment.

What he reported was this: It's known that neutrons and protons attract one another. When you fire a proton at a neutron, or vice versa, there should be some deflection it in their course, but it goes on through and comes out the other side, only moderately changed. What was happening here was that sometimes the neutrons and protons bounced right back at one another as if they hit a brick wall.

So I got up in the question period and I said, "Maybe the reason is that inside the nuclear force of attraction, which holds nuclei together, there's a very strong short-range force of repulsion, like a little hard sphere inside this attractive Jell-O. And when the neutrons and protons hit this strong force of repulsion, they bounce back as if they've hit a billiard ball." That, of course, violated basic ideas on the theory of relativity, or at least so it seemed to people at that time, because it selected the space dimension in a way that didn't fit into the four-dimensional continuum of Einstein's ideas.

I'll never forget, Oppenheimer got up, he liked to needle the young fellows and he said, very dryly, "Thank you so much for, we are grateful for every tiny scrap of help we can get." But I ignored his needle and pursued my idea, and actually calculated the scattering of neutrons by protons. I showed that it fit the data very well. Oppenheimer read my paper for the Physical Review and took back his criticisms. This work became a permanent element of the literature of physics.

GCMI: How did you get involved with NASA?

DR. JASTROW: I was working on the Vanguard Project at the Naval Research Lab trying to figure out a quick and easy way of determining where satellites would come down when they re-entered the atmosphere. In the meantime Kruschev, as a part of the Cold War, claimed that the rocket casing of Sputnik had come down in Alaska and we had it and he wanted it. I went to a meeting in Moscow and presented results which showed from the last radar sightings on the height of this thing that it had actually come down somewhere in an arc between Siberia and China. And this drew the attention of people who, unbeknownst to me, were at that very moment planning to set up a U.S. space agency. They asked me to join NASA. Which I did, the month it was formed, that was October, 1958.

GCMI: When you started at NASA, was there a clear vision as to what it was going to do?

DR. JASTROW: Yes. I help set up a lunar exploration committee with Harold Uri and others. NASA was already thinking about landing on the moon.

GCMI: At the time did you consider this a desirable and achievable goal?

DR. JASTROW: The moon, as I wrote in a magazine article, was the Rosetta Stone of the solar system. On the earth, everything that happened in the past has worn away. But the moon is geologically dead, has no atmosphere to speak of, and it preserves everything that has fallen on its surface throughout the history of the solar system; it's all lying there waiting for us to read it. So the moon was uniquely valuable; we all knew that.

GCMI: What did we actually get out of going to the moon in terms of science?

DR. JASTROW: We learned when the new moon was formed, which is a date for the age of the solar system, and we learned that early on there was an episode of flooding by lava that created these great dark blotches on the face of the moon and make up the facial features. And in that way we confirmed similar episodes must have happened on the earth, except because of its larger bulk the Earth would have retained its heat so it's still volcanically active today. And we also learned something about the primordial substances that made up the planets.

I had no illusions that we were going to the moon for the science. The main point was to refute what some were thinking, "The U.S. is on the way downhill, and it can't match the Soviet's technological achievements'." The science was just icing on the cake.

GCMI: What was to be the next step if things that stayed on as aggressive track?

DR. JASTROW: I think we would have set up a interferometer on the moon and started doing astronomy. It's an excellent place to do astronomy. Much better than doing it in space.

GCMI: If you were running NASA today, what?given the resources available?would you do?

DR. JASTROW: I would put a lot of effort into developing a low-cost launch technology with the commercial sector. NASA's predecessor organization, the NACA, did much to develop the technology that made the commercial aircraft industry possible. It has been a major contribution to our economy, both directly and indirectly. Now we need low-cost launch capability.

GCMI: Let's move on to your current work in astronomy. You direct the Mount Wilson Observatory in Pasadena, California. How can you see anything when you are near an urban area?

DR. JASTROW: The smog actually is very beneficial because it results from a temperature structure in the atmosphere that keeps most of the turbulence of the atmosphere below the level of telescopes. Above it, the air is still and quiet.

Now, very recently we have taken advantage of the smooth air over Mount Wilson to build a device based on Star-Wars technology which collects the rays of light that have been scattered somewhat on passing through the atmosphere and straightens them out and produces an image as sharp as if the whole hundred-ton telescope were in space. It's called adaptive optics, and we are getting the sharpest telescope images that have ever been obtained in the history of astronomy with this device.

Another device, which is nearly finished, does the same thing but with the addition of a laser beam that creates an artificial star wherever you want to have an object you want to look at. So if you're looking at a very faint distant object, you can use this laser star to figure out what the atmosphere is doing, apply the corrections to the light that's creating the nearby image of the faint distant galaxy, and in this way you can extend the range of your vision out to cosmological limits once more.

GCMI: Let's discuss some of your writings. You worked with your mother on two books about immigrant life in New York City.

DR. JASTROW: It was a great deal of fun. I look back on that time in New York City regretfully. The values were different then and it was nice to write about that.

GCMI: Of your science books which is your favorite?

DR. JASTROW: The Enchanted Loom, the story of how the brain evolved by strictly Darwinian mechanisms. That this should happen out of inanimate matter is extraordinary, a fascinating story. And it has implications for intelligent life in the universe also.

GCMI: Which are?

DR. JASTROW: Which are that if it happened that way here, could it happen elsewhere? There are arguments that it's a rare event, but I think there are counter-arguments that are stronger.

GCMI: You've written that the Big Bang is at least consistent with the idea of a creator or a first cause.

DR. JASTROW: The theoretical cosmologists are very active inventing various exotic ideas for a non-deist first cause, and that means, of course, the possibility of the creator. I'm an agnostic because I see the thrust of the discoveries toward the idea of a first cause, but everything else I know about humankind and the universe tells me that it could have happened without an overarching plan. And yet, when you step back and look at the whole picture that seems hard to believe. So as I've said in a number of places, I'm just stuck in the middle.

GCMI: Well, one of the reasons that some people argue that the Big Bang suggests a first cause is that the series of events leading to life are so complex as to be impossible to imagine without a creator, the so-called anthropic principle.

DR. JASTROW: The probability of any particular link in the chain occurring is small. But the number of alternate possibilities that would lead to approximately the same result is unlimited. So you take zero and multiply by infinity, you can get a finite number. And I believe that's what happened. That there should be a chain of events leading precisely to you and me sitting here today has essentially vanishing probability, but the larger aspects of the picture involve many different pathways, and adding them all up together the probability is not small.

GCMI: That matter should come together in a way to create carbon is nearly miraculous, isn't it?

DR. JASTROW: But if that didn't happen, something else could have happened. We have what's called carbon-chemistry chauvinism in our outlook, and we shouldn't be misled by that. It's true that if you change the nuclear force a little bit you get different outcomes that would seem to preclude the kind of universe we live in, but I think that's also flawed reasoning because we now know that of the four great forces of nature: the nuclear force, so-called weak force, electricity, and gravity, three of them are now known to be manifestations of one single force. The only one that hasn't been brought into this unity now, so far, is gravity. And that may in the future be brought in as well.

There's a lingering uneasiness in my mind, however, as to whether we have unearthed the true meaning of all this. We step back and look at the whole thing, you feel impelled to ask, "What is the purpose of it all?" Here's this extraordinary phenomenon of life and intelligence unfolding out of these beginnings, and it's a very progressive picture and moves from point to point in those upward, if you will, and onward, and you wonder if that really doesn't call for the existence of some entity that's watching over the situation, and nurturing it. And as I said earlier, I'm standing in the middle.