New Scientific Discoveries

What do you see as important avenues of future research for a young astrophysicist? Are there certain areas where we're on the verge of important breakthroughs?

Oh, absolutely. Astronomy is on several thresholds for various substantial advances. It's been quite amazing in the last decade, perhaps the last two or three decades even, but, particularly [more recently]. It seems to be increasing in this potential, and our understanding, especially of cosmology -- the universe and its beginnings -- has been increasing substantially. It is driven, as is most science, by experiment. The theory is very important; theoretical work, which is what I do, is very important, but it doesn't drive the subject. We are trying always to understand observations or measurements or experiments. Of course, in creating models, we actually make predictions which then can be tested by other experiments. But still, the subject itself is driven by observations.

Big telescopes are being put together and designed and conceived, and if any of them get built (of course, they become very expensive), it's going to be a transforming thing, as far as astronomy is concerned. Some major questions will be answered.

Your first lecture was really interesting -- and I am not a technical person, so I must admit I couldn't follow everything -- but what was really interesting was the simplicity of taking the physics, and the step-by-step way in which you came to an understanding of the building blocks of the universe. That was what I drew from the lecture.

The lecture was more successful than I thought.

What was particularly intriguing was that you led us down a path that raised the question of positioning us in the future to understand all kinds of questions. For example, how human life came into being. Talk a little about that.

I was simply trying to put together a plausible account of how the universe must have evolved to the point where complex systems, complex molecules, were actually created. Life is the most complex of all the systems. So it seems to me that especially in this millennium, that question is the fundamental basic question that remains to be addressed in a serious way.

I was just striving to look for a simple explanation, a step-by-step explanation of how [the present universe] of complicated systems, in the beginning, was very simple; there were no constant entities. It was how we got from such an unpromising scenario to the present situation, and then settled to a sequence of steps, and no giant steps [at first] -- the giant step will be life itself. The other steps were more or less smooth and one could make sense of it. It was a progression that could well have happened.

Let's go back to this point about the future areas of research. Give us an example or two of places in these fields that are on the threshold of answering some very interesting questions.

That question is often asked, and the answers are usually wrong. So I'll give you my best answer, expecting that it will turn out to be something else that's really important.

But that's what science is about, right?

Yes, you have to make a decision and then you'll find out if it's right or not.

I think the two major areas in astrophysics are clear, so in some general sense, my answer is correct. One is cosmology. That is being driven by new telescopes, instruments in space which have a higher resolution, a greater frequency coverage, greater sensitivity, greater spectrum and special resolution. Those, married to the present theories, will answer some really significant questions.

Such as?

The universe is, of course, expanding, we're not arguing about that. But there is this presentation, or argument, or demonstration, perhaps, or evidence that suggests that the acceleration is increasing, that there is a repulsive force in the universe called dark energy, and we don't know what it is. We're on the edge of possibly finding out something significant about the origin of dark energy, and the origin of dark matter. There's also missing matter in the universe. So the two major questions are the source of the dark energy and the source of the missing matter. I think we are on the edge, at least, of learning substantially about those aspects.

The other [question] is this marvelous work on the extra-solar planets -- something over 100 extra-solar planets are now being found. To be able to compare them with the earth and with the solar system planets will be enormously exciting. We'll see. Maybe it's the question of life and how it began, this question of whether the conditions that are appropriate for life occur elsewhere or have occurred elsewhere; or are we unique? Maybe we'll be able to address that question once we have an array of objects, and we can start to make comparisons.

So, this exploration will continue of extra-solar planets and their properties. At the moment, an understanding of them [is limited]. The observation is just gross: "There they are; yes, they had been found, they are there." We know very little about their atmospheres; but that will change with their observational development.

I always say it's driven by observations, and it will [continue to] be. But those are, for me anyway, the two most interesting areas in astronomy.

In preparing for this interview, I read a press release from Harvard about a recent discovery, which I don't want to misrepresent, that you were involved with in working with antimatter.

Oh, did you?

Yes, yes. Help us understand the importance of that.

Only marginally important in astronomy. There is a question about matter and antimatter, and why it is that we seem to be made only of matter, and there's no evidence of antimatter. On Earth, we can make antimatter, at least temporarily, and so there are fundamental questions that could be answered if experiments could be done. [For example,] does antimatter weigh exactly the same as matter? If you take a proton, does it weigh the same as an antiproton? There are questions that can be answered by comparing antimatter and matter, and if they turn out to be different, other than just in their charge, then the fundamental assumptions underlying physics will have to be modified. This is a fundamental question of physics, and two fundamental principles would be tested by experiments comparing matter with antimatter. One simply wants to see -- are the properties of matter any different from those of antimatter? If they are, then physics at its most fundamental level will have to be modified.

I was interested in atomic molecular physics as such, independent of astronomy. So there's this interesting question: if you have antimatter, how would you know you have it? Its properties are the same as matter, so how can you tell the difference? So I was addressing that question: if I have antimatter and matter together, what might happen that will tell me, yes, I do have antimatter -- other than just annihilation? That was an interesting question.

Do you find yourself thinking about these problems even when you go home from work -- assuming you ever go from work? In other words, do insights, creative moments -- by that I mean not just discoveries, but definition of the problem -- come to you at all hours of the day?

That's a very good question, especially the distinction made between the discovery and definition of the problem. I would say, no. At home, I don't really discover. I don't remember ever just sitting there and something comes into my mind. But I do organize the material. I do focus it and quite often find myself putting it together in a slightly different way, and asking the question in a slightly different way -- not answering it, asking it, like I said, the difference [that you mentioned]. I answer the question when I'm at work, in my office, and if I'm walking around, yes, sometimes when I'm just walking around. Yes, one tends to think of this problem all the time.

What is that creative moment like? Not the big discovery, necessarily, but this shift in the focus, the reorganizing of the problem that must generate, then, a new set of activities and a new set of work.

It's very exciting, in fact, and drives one back to work and saying, "Oh, yes, yes, I must get back to this! Yes, maybe that will work." You have ideas, and when you work them out, you're going to find most of them fail. So to have a new idea, or even just a new description of the material of the idea, it's fun.

I gather in all areas of science, but especially in the areas that you cover, there's a synergy between the different subjects that you've mastered. I'm hearing you say that mathematics has been essential for what you do, and I assume new developments in mathematics, that physics itself, physics and chemistry, I gathered from your lecture, are very important. And then, obviously, astrophysics, and so on. So as we move along in our understanding of the world, there is really a great synergy that emerges from interdisciplinary work and your knowledge of these different disciplines. Is that fair?

Well, it's fair. It happens to be my style of research and my interests. I should say that the mathematics in my work isn't cutting-edge mathematics. It's the kind of mathematics that everybody should have. We are not using (except a few people, perhaps) very sophisticated mathematics; but fairly challenging, all the same. But the physics and chemistry are absolutely crucial to what one is trying to do, to understand these astronomical phenomena in terms of the physics and chemistry that we've learned on the earth. That is the purpose of it, to explain it in terms of familiar physics and chemistry. So we have to know the physics and chemistry; that's crucial.

Of course there are areas of astronomy where the requirements are different, perhaps. But still, to be effective, and even to be comfortable in talking about astronomical phenomena, you need to have a firm, secure basis in physics and chemistry.

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