If one is called upon to name the true pioneers of SETI, there are only three: Frank Drake, Giuseppe Cocconi, and Philip Morrison. Morrison died in his sleep on April 22, at the age of 89.

It was while he was at Cornell University, in the late 1950s, that Morrison, together with his physicist colleague Cocconi, made the fundamental calculation that justified a search for signals from other worlds. He was motivated to do this while considering the generation and detection of gamma rays, and whether these types of particles could be used to send signals across interstellar distances. While this seemed possible, it occurred to the two researchers that radio might be a better communication medium (Morrison had acquired a crystal set at a very early age for listening to the broadcasts from KDKA, the country's first commercial radio station, in his home town of Pittsburgh, Pennsylvania. Morrison soon became an avid radio amateur.)

The physicists wrote up their calculations showing that radio technology, even at the level current nearly a half-century ago, was easily capable of sending information across light-years of distance. They speculated that, since advanced societies might be making their presence known with such emissions, a search for signals should be made by radio astronomers. This result appeared in an article the two physicists wrote in 1959 for the British journal, Nature - and that became the undisputed seminal paper in the history of modern SETI research.

A year later, Frank Drake spent several weeks using a radio antenna in West Virgina in the first deliberate search for the type of signals hypothesized by Cocconi and Morrison. "We started the search program without knowing of their work, although we had made the same sort of calculations," notes Drake. "Nevertheless, this idea was a highly speculative concept, and it was very good to see that Phil Morrison, one of the world's leading physicists, was of the same mind."

Morrison soon joined the MIT faculty, where he continued to be involved with the SETI enterprise, helping to facilitate meetings and publications on the subject. While never a major component of his research, his insights and creativity continued to supply important input to this field. As an example, when the NASA SETI program was inaugurated at Arecibo, Puerto Rico in 1992, Morrison gave a review talk on the subject that was remarkable for the breadth and freshness of its ideas.

Many will be familiar with Morrison from his popular book Nothing is Too Wonderful to be True, as well as the many book reviews he and his wife Phylis wrote for Scientific American. He also narrated the well-known short film by the Eames brothers, Powers of Ten and, together with Phylis, authored a book of the same title.

It is with regret that the SETI Institute notes the passing of an extraordinarily talented scientist, and one who laid the foundation for what has become such an earnest, exciting and promising enterprise.