Subrahmanyan Chandrasekhar was a famous astrophysicist. He won the Nobel prize in physics in 1983, for work that led to the concept of black holes. The whole December 2010 issue of Physics Today was devoted to Chandrasekhar, marking the centenary of his birth.
There is a fascinating interview with Chandrasekhar which appears at the back of the biography, Chandra by K. C. Wali. Here are a few extracts:
SC: In fact, I consider myself an atheist. But I have a feeling of disappointment because the hope for contentment and a peaceful outlook on life as the result of pursuing a goal has remained largely unfulfilled.
KW: What? I don't understand. You mean, single–minded pursuit of science, understanding parts of nature and comprehending nature with such enormous success still leaves you with a feeling of discontentment?
SC: I don't really have a sense of fulfillment. All I have done seems to not be very much.
KW: Don't you think that is common to everybody.
SC: Well that may be, but the fact that other people experience it doesn't change the fact that one is experiencing it. It doesn't become less personal on that account.
SC: What is true in my own personal case is that I simply don't have that sense of harmony which I'd hoped for when I was young. I've persevered in science for over fifty years. The time I've devoted to other things is miniscule.This contradicts the view of another atheist scientist (and Physics Nobel Laureate) Steven Weinberg who suggested the only meaning that can be found is in doing science. (See this earlier post).
The above interview features in a talk Scientists and their Gods by Fritz Schaefer.