The value of an outstanding mentor

James Van Allen was a truly remarkable teacher, working in a gentle but persistent way. His most powerful tool was his use of the carefully phrased question. It invariably caused us students to go away and think critically about the issue and to come up with our own solutions. If we made wrong assumptions or arrived at wrong conclusions, he would gently steer us in the right direction.

Many of us have expressed our admiration for Van Allen’s willingness to turn students loose on such important projects and to give us great freedom in carrying them forward. His guidance provided just the right amount of direction to advance our skills and understanding of the work, but at the same time to keep us from getting into too much trouble. Only with later widening experience did I come to appreciate the immensity of the risks he took with us.

Although we all made our individual contributions toward the State University of Iowa Physics Department’s rise to leadership in the new branch of research, it was Van who provided much of the vision, gained a major portion of the outside programmatic and financial support, and had the most to lose if we failed.

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I visited with Van only a few weeks before he died, and we talked of many things. One of our topics was the discovery of the Van Allen Radiation Belts.

Van had posed a question to me a few months earlier: “Would we have discovered the radiation belts with Explorer I alone, if we had not had the onboard-recorded data from Explorer III?” We exchanged independent written responses before the visit. In his response, he asked further, “Would we have concluded that our detector on Explorer I was hopelessly erratic and despaired of getting any credible data? Or would we have persisted in reading and compiling the data, recognized the dead time problem, and made the radiation belt discovery? If so, how long would this process have taken?”

Van asserted that we would have organized enough Explorer I data so that we would have discovered the high intensity of geomagnetically trapped energetic particles, but he did not speculate further. My response was that we would have made the discovery, but that it would have taken longer. I further speculated that we would likely still have made the announcement before the Soviets, but posited that the trapped radiation announcement would have been less dramatic and have had less impact on jump­starting an energetic space research and exploration program.

He also asked during our visit, “Do you know that a detailed description of how the proximity fuse worked has never been written?” It is remarkable but typical that, even as he lay in his bed near the end of his life, his writing pad was on his bedside table, and he had begun drafting a paper on that subject.

Van was a truly remarkable person, and I was indeed fortunate to have had him as a mentor and friend