A Journey to Bridge Math and the Cosmos
By CLAUDIA DREIFUS |

**C**AMBRIDGE,
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.

Advertisement

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.

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

**Petters**. 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.

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

**Petters**. 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.

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

**Petters**. 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."

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

**Petters**. 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.

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

**Petters**. 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.

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

**Petters**. 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.

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

**Petters**. Oh, yes. You know, I didn't really understand
race as a concept until I came to America, when strangers on the
street called the "n" word at me. In Belize, I grew
up my preteen years without being demeaned, and yet, once I got
here, with all the opportunities I enjoyed, I've suffered from
racism too.

I've gone to professional receptions and been mistaken for a waiter. I was at a certain prestigious institution, at a reception welcoming new students, and I was the only one of color there. When I walked into the room everyone turned around and stared at me.

I walked over to the nearest table of people that looked my age and introduced myself. To make conversation, I asked someone how one got to a certain office in the building. "Make a left, or you can tie a rope to the ceiling and swing over to the other side," this person answered.

When this happened, I went back in my mind to the whites I met in Belize, who'd treated me fairly. I said to myself, "Everyone is not like this person." If I had grown up in the U.S., where you get bombarded by this stuff from childhood on, maybe I wouldn't have had it within myself to go on. That's why I think we need affirmative action. Racism injures people and unfairly holds them back.

**NYT**. Less than 1 percent of mathematics Ph.D.'s are
African-American. Is there anything that can be done about that?

**Petters**. I feel that people like me and others can provide
a powerful role model because we give young people an opportunity
to see someone like them doing this kind of work. And they see
that we're happy, not bitter, full of energy, planted in a solid
place. That's powerful.

Every year during Black History Month I get about a hundred e-mails from kids doing projects. They ask about what it is like to have a career in math. I answer them all - just like David Blackwell, who is one of the top African-American mathematicians in the country - once answered my letter.

At a senior level, I am involved with the Conference for African-American Researchers in the Mathematical Sciences. We have an annual meeting where mathematicians and students come together in a nurturing setting. Role models are crucial.

**NYT**. What difference does it make who teaches general
relativity? If ever there was a raceless subject, wouldn't this
be it?

**Petters**. Well, the classroom experience is not completely
raceless. I know of cases where certain white professors ask minority
students, "Are you sure you belong in this course?"
and show shock when such students excel in their advanced courses.
It makes a difference for minority students to see a person like
them teaching such courses.

**NYT**. Your specialty within mathematical physics is "gravitational
lensing." What exactly is that?

**Petters**. Gravitational lensing is when gravity in space
acts as a lens. This phenomenon produces cosmic mirages that carry
signatures about the nature of dark matter, black holes and the
age of the universe. My current research develops the mathematical
infrastructure and tools for addressing these issues.

You see, in 1936 Einstein wrote a short essay where he studied a star lensing another. If the background star is off the line of sight, you'll see two images. If it's on the line of sight, it'll appear as a ring. You could then ask the question, Well, what if the lens is not just one star, two stars, what if it's a whole galaxy of stars, billions of stars? Or what, if it's collections of galaxies?

In order to tackle something like that you have to lay a mathematical infrastructure to pose such questions and to develop a set of tools by which you could address the multiple imaging. I am the co-author of a book where we laid out an entire mathematical foundation for the subject of gravitational lensing, in a sense abstracting out of Einstein's essay.

**NYT**. When you make your calculations about what the
universe is like, is that a way of putting yourself into a place
that is race-free?

**Petters**. Yes, it's the place where I can be with God.
I am a person of faith, have been since childhood. When I do my
work, I feel blessed with existence, blessed with life, and I
can take refuge from human foibles.

article by Claudia Dreifus. from May 27, 2003 New York Times