Sir

I read with sadness about the passing of Victor Weisskopf (Nature 417, 396; 2002). Twelve years ago, in San Juan, Puerto Rico, I was sitting next to an empty seat on a plane, wondering which of the many oversized people with too much carry-on baggage I would have to put up with for the flight to Boston. An elderly man sat down next to me and we began chatting: it was Weisskopf.

For five glorious hours I — who as a teenager had wanted to be an astronomer before I realized that my mathematical abilities were woefully inadequate to the task — plied Weisskopf with questions about physics and cosmology. In his turn, he posed penetrating questions about my own field of large-whale biology.

Weisskopf had all the hallmarks of a great scientist. He was ungrudgingly generous with his own vast knowledge and happy to share his insights with an interested stranger; and he was insatiably curious about everything in the world around him, whether or not relevant to his own work.

The unique and fortunate nature of my experience that day was not lost on me. After all, how often does one get the opportunity to ask one's seatmate, “So, do you think that general relativity and quantum theory will be unified in the foreseeable future?” and have the expectation of an informed reply?

The answer, by the way, was “No”.