CAMBRIDGE, Mass. — Dr. Arlie O. Petters grew up in a quiet corner of Belize, far from the intellectual centers of mathematics and physics and unaware of many of his career possibilities.

Today, as a United States citizen and the Martin Luther King Jr. visiting professor of physics at the Massachusetts Institute of Technology, Dr. Petters, 39, is building a career bridging the fields of abstract mathematics and astrophysics.

He received his bachelor's and master's degrees from Hunter College in New York and his Ph.D. from M.I.T., studying at Princeton and later teaching there. Now, he is on leave from his post in the mathematics department at Duke.

His book, "Singularity Theory and Gravitational Lensing," written with Dr. Harold Levine and Dr. Joachim Wambsganss, develops a mathematical theory of gravitational lensing, a phenomenon in space that distorts perceptions of stars and galaxies.

On a warm spring afternoon, at his M.I.T. office, Dr. Petters detailed the journey that brought him from the magic realism of rural Central America to the magical realities of cosmology and mathematics.

Q. As a child growing up in Central America, did you look up at the stars and ask big questions about them?

A. Yes, I did exactly that. My town, Dangriga, had no more than 3,000 people and barely any electricity. I studied under a kerosene lamp. There were barely any books.

At night, I'd look up at those stars and for some reason they captured me deeply inside. I'd ask questions like how did the stars get there, what were they? They twinkled; what was that, really? And the vast expanse of it all begged all kinds of philosophical questions.

Q. As a child, did you even know of anyone who was an astronomer?

A. No one around me had studied beyond high school. I had a cousin who did go to high school, and I viewed him as the smartest person around. I used to bug him with my queries. In the context of a poor rural community, you don't know where to take your inquisitiveness. You have to go after your ideas on your own.

Although I knew no astronomers, I knew artists and did art. There were artists in my town that made things for the tourists. What linked art with the cosmos and mathematics was, I discovered, that the same feeling you get when doing art comes when you solve mathematical problems related to the cosmos. With time, I realized that mathematics wasn't just calculating, but a powerful way of thinking.

Q. Without anyone to guide you, how did you work out a career path?

A. I was fortunate to meet people from outside of Belize. We had Peace Corps people teaching in our high school. From one of them I learned about physics, our solar system, galaxies and the universe. He was the first person to say to me, "It's O.K. to think about these things intuitively, but you also have to get a grip on your ideas in a scientific way. You need the language of mathematics to shape and process ideas to make predictions."

Q. How did a teacher's good advice lead to a career in mathematics?

A. I was raised by my grandparents because my mother had immigrated to New York. She married a U.S. citizen, and I joined them when I was 13. New York was like a candy store of knowledge. I was amazed by the amount of knowledge that exists in this country, just limitless.

I went to Canarsie High School in Brooklyn, which had courses for students like me who were obsessed with science and math. Seeing how math impacts the scientific process and vice versa inspired me to pursue mathematical physics. After Canarsie, I attended Hunter College.

Q. Were you in Hunter's special science program for minority students?

A. Yes, though not at first. It was interesting how that came about. I had a lot of tough personal problems at home. My stepfather and I did not get along. (We have since made up.) It came to a point where I couldn't take the situation anymore, and I left home. I was essentially on the streets of Brooklyn.

This occurred in my first year at Hunter College. And I remember reading a poster about this Minority Access to Research Careers, MARC, fellowship, which is sponsored by the N.I.H. This must have been like May or so. They had already selected the recipients for the next year.

I approached the head of the program, Jim Wyche, and said to him: "I've left home, I have no money, I'm bumming around, living in different places. My grandmother wants me to immediately return to Belize. Would you consider me for the fellowship this late?"

He spoke to people. Within like two weeks, I had the fellowship and he'd found housing for me at the Hunter dorm. Without that — without what now would be called affirmative action — someone like me would have ended up back in a field in Belize picking citrus.

Q. You've clearly benefited from affirmative action. Do you support the concept?

A. Passionately. I believe that minorities and white females have truly benefited from affirmative action. I think you could even broaden it for economically disadvantaged whites.

Q. Astrophysics is obviously a meritocracy. Nonetheless, have colleagues sometimes held your affirmative action background against you?