Letter from Thomas Gold to Dr Gordon Pettengill, Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts Congratulates him on his election to the National Academy. States it has finally sunk in that Pettengill's work on planetary radar is important. States he is free to choose the section in the Academy with which he wishes to be associated; Gold hopes that it would be geophysics, which will best represent Pettengill's interests and contains most of his colleagues whose interests overlap with his. 1 May 1979